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by Patrick McCully
A Bright Future For Hydro – Without Dams
From March 2010 World Rivers Review
A quiet revolution is underway in the world of hydropower. An emerging non-dam based hydro industry holds the promise of economically viable technologies that do not deplete resources or warm the planet, and do not wipe out species, ecosystems and cultures. With supportive policies from governments, non-dam hydro could become a key part of the world's energy mix over the coming decades, and could, as wind power already has, overtake big-dam hydro in terms of its share of new capacity additions.
A tidal turbine
Non-dam hydro comes in a diversity of forms. It includes all technologies to generate electricity using water without dams. The two sectors receiving the most attention are wave power and "hydrokinetic" turbines that capture energy from the flow of water in rivers, estuaries and ocean currents, and even irrigation canals and water supply and disposal pipes. (Hydrokinetic turbines are also referred to as "instream," "stream" or "free-flow" turbines. They should not be - but frequently are - confused with "run-of-river" hydropower which includes a dam, but usually not a large reservoir).
Not all non-dam hydro technologies may be benign and environmentally appropriate at all sites, but it appears likely that many of the technologies could be very low impact compared with dam-based hydro and other conventional generation technologies. While the output of river flow hydro will, like run-of-river dams, be reduced in dry seasons and droughts, tidal and ocean power is highly dependable and can help reduce the vulnerability of electrical grids to climate change.
Funding for R&D of non-dam hydro has been meager until very recently, but is now being rapidly ramped up from both public and private sources, especially in Europe and North America. "We're at the stage of needing to see which of these technologies works and whether they can be scaled up," said Neil Kermode of the European Marine Energy Centre, in a December interview with the BBC. "That requires steady investment. Look what the Danes did with wind: investments year after year paid off and now they earn billions in exports. There is huge potential - absolutely huge amounts of energy out there - in fact we don't know how much but it is epic."
Unconventional Potential
In January 2010, consulting firm Pike Energy published the most comprehensive assessment yet of global non-dam hydro potential and possible rate of deployment. Pike estimates that if the European Union and US continue to increase incentives for non-carbon energy, by 2025 the world could have installed 3,000 megawatts (MW) of river flow turbines, 4,000 MW of ocean current turbines, 57,000 MW of tidal stream turbines and 115,000 MW of wave energy. By comparison, current global installed large hydro capacity is around 770,000 MW.
It would be a heroic feat to achieve the Pike forecasts - it would mean adding in 15 years a quarter of what the big-hydro industry took more than a century to install. In any case, the numbers are necessarily speculative given that the technologies are only just being commercialized and the available resource is very poorly mapped. But the Pike estimate is an indicator of what could be done with each technology.
Hydrokinetic technologies include turbines that look just like underwater wind turbines built on the riverbed or hanging upside down from barges anchored in the river; barges with turbines like water wheels on old-fashioned paddle-steamers; "helical turbines" that look like the blades on a hand-pushed lawnmower; and, more experimentally, hollow cylinders placed horizontally across rivers that move up and down as the river flows past them.
Underwater turbine
There appear to be no significant engineering challenges to installing and operating free-flow turbines in rivers. Research and development efforts are focused on bringing down costs and ensuring that the turbines and associated facilities do not harm fish or other aquatic life. So far it appears that the environmental impacts of the technologies will be low, although as their use is scaled up it will be important that their cumulative impacts are carefully monitored and that they are sited to avoid environmentally sensitive areas and disruption to river navigation and recreation.
The drawback to river-flow technologies compared to conventional hydro is that the potential energy from a given volume of falling water, which is what is exploited by an old-fashioned dam-based plant, will always be far greater than the kinetic energy from flowing water. So the laws of physics dictate that non-dam systems can never extract as much energy from rivers as can dams.
The first river flow turbine to enter commercial operation in the US came fully on-line in August 2009. The small turbine, capable of producing just a tenth of a megawatt, and looking something like a household blower fan, hangs beneath a barge immediately downstream of a navigation dam on the Upper Mississippi River at Hastings, Minnesota. Initial monitoring reportedly shows that the turbine is almost completely safe for fish.
A 2007 report from the Electric Policy Research Institute (EPRI) estimates the US river hydrokinetic potential at 10,800 megawatts (around a sixth of the existing installed capacity at US big dams). A 2009 study for the National Hydropower Association by Navigant Consulting projected that with current incentives for renewables in place, 500 MW of hydrokinetic turbines could be installed in US rivers by 2025. With a clear policy commitment to this new energy source, 2,000 MW could be installed.
There is also a small, but useful, potential for "conduit hydro" - kinetic turbines installed in pipes and irrigation canals. The beauty of conduit hydro is that it has almost zero environmental impact. The California Energy Commission estimates that the state has the potential to generate 255 MW from existing pipelines and canals. In neighboring Nevada, wastewater from Las Vegas will soon be flowing through two 8 MW turbines on its way from a new treatment plant into the reservoir behind Hoover Dam.
Since 2005 the water piped down from a nearby mountain reservoir to supply Bogotá has flowed through a 13 MW hydro project. Areas with extensive canal irrigation networks such as the Indus valley in Pakistan and the plains of northern India should have considerable conduit-hydro potential.
A Sea Change
Worldwide, the bulk of hydrokinetic power potential - and investor interest - lies not in rivers and pipes, but in tidal streams and ocean currents. Navigant Consulting predicts that over the next 15 years the US could see the installation of 250 MW of ocean current power (all from the Gulf Stream flowing past the southern tip of Florida); and 400 MW of tidal stream power. With improved policies, three times more ocean current power could be exploited, and ten times more tidal power. Marine hydrokinetic power is particularly attractive as currents and tides are very predictable and reliable.
Extracting energy from the seas does pose unique challenges given the harshness of the ocean environment, the remoteness of some of the best sites, and the expense of building reliable infrastructure to bring power from the project to the shore. The potential for these technologies, however, is extremely high and the challenges are mostly ones that engineers are already familiar with in other contexts (e.g., installing and maintaining offshore oil platforms, and delivering power from offshore wind farms).
Seagen, the world's first commercial tidal stream turbine, was installed in 2008 near the narrow mouth of Strangford Lough, a coastal inlet in Northern Ireland. (It's an appropriate location for this first - Strangford Lough is also the site of the world's oldest excavated tidal mill, built by 8th century monks to grind their grain, showing the venerable history of tidal power technology). Seagen has a capacity of 1.2 MW, enough to power 1140 Ulster households.
Strangford Lough is legally recognized as an "Area of Outstanding Natural Beauty," and the impact of Seagen is being closely monitored. So far there have been no reports of significant harm to the marine environment, and as the structure is mostly submerged it has little scenic impact. The same technology is slated to be installed next in a 10.5 MW project off the coast of Wales, and the company behind it is now exploring the potential of the Bay of Fundy off Eastern Canada, site of possibly the world's most powerful tidal current.
Voith Hydro, one of the world's largest suppliers of conventional large hydro turbines, is testing a new tidal turbine design in Korean waters and is an investor in a plan to build "the world's first tidal current power park," a 600 MW project in Jeollanam-do Province.
While tidal current technology appears likely to be very low impact, the same is not true for the better-established tidal barrage schemes. A tidal barrage is essentially a low dam across an estuary. Tidal barrages can generate very large amounts of power, but can cause seriously harm estuarine ecosystems by changing their salinity and sediment flow patterns, blocking passage for fish and marine mammals, and flooding coastal mudflats which have major wildlife value, especially for shore birds.
The British government is currently studying options for a major barrage in the Severn estuary between England and Wales. One of the options under serious consideration is a 8,600 megawatt power plant that could supply more than 4% of total UK electricity generation. Most of the large UK environmental groups oppose this megaproject.
Wave of the future
Britain and Ireland have one of the world's biggest concentrations of wave power potential. The resource is sufficient to supply 16% of the UK's electricity. The UK Carbon Trust estimates that up to 2500 megawatts of wave power plants could be installed across Europe over the next decade. EPRI estimates that by 2025 the US will have installed 900 megawatts.
The world's first offshore wave farm to enter commercial operation is the Pelamis "sea snake." The initial Pelamis scheme, installed off the coast of Portugal in 2008, had three floating cylinders made of hinged segments, each with a capacity to generate 750 kW. The scheme, however, had a tragically short life. Its cylinders sprang leaks and had to be towed off for repairs only two months after its deployment.
The company behind Pelamis is now working on a second generation machine. In December 2009 they announced a joint venture with Swedish utility Vattenfall to build a wave project off the Shetland Islands in the North Sea, up to 20 megawatts in size.
Brazilians have a joke that theirs is the country of the future ... and always will be. For years, wave and tidal power similarly seemed to be on the verge of a breakthrough into the big league of power sources, but for technical and cost reasons failed to meet the promise. Today, concerns over climate change and a sharply rising tide of political support for renewables, coupled with steady technological progress and investor interest, mean that the future has finally arrived for the new hydropower.
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A primary plant cell wall network was computationally modeled using the finite element approach to study the hypothesis of hemicellulose (HC) tethering with the cellulose microfibrils (CMFs) as one of the major load-bearing mechanisms of the growing cell wall. A computational primary cell wall network fragment (10 × 10 μm) comprising typical compositions and properties of CMFs and HC was modeled with well-aligned CMFs. The tethering of HC to CMFs is modeled in accordance with the strength of the hydrogen bonding by implementing a specific load-bearing connection (i.e. the joint element). The introduction of the CMF-HC interaction to the computational cell wall network model is a key to the quantitative examination of the mechanical consequences of cell wall structure models, including the tethering HC model. When the cell wall network models with and without joint elements were compared, the hydrogen bond exhibited a significant contribution to the overall stiffness of the cell wall network fragment. When the cell wall network model was stretched 1% in the transverse direction, the tethering of CMF-HC via hydrogen bonds was not strong enough to maintain its integrity. When the cell wall network model was stretched 1% in the longitudinal direction, the tethering provided comparable strength to maintain its integrity. This substantial anisotropy suggests that the HC tethering with hydrogen bonds alone does not manifest sufficient energy to maintain the integrity of the cell wall during its growth (i.e. other mechanisms are present to ensure the cell wall shape).


Evaporation is one of the oldest PVD method ever used in coating technology especially the thermal evaporation that it consists mainly in transferring heat to a material in a vacuum environment (10-6 mbar or lower), so that the material get to the vapur phase and spread all over the chamber condensing on the surrounsing surfaces.
The heat is usually transferred applying a current to a metal crucible(usually named boat) that transfers the heat to the material that is inside by Joule Effect.
In the e-beam evaporation the heat transfer is given by an electron beam focused on the material to be melted; e-beam evaporation is selected in for high temperature melting materials.
In the e-gun evaporation the material "evaporation speed" (evaporation rate) should be kept stable to better seek a compromise between speed and film quality. To maintain an adequately constant deposition rate, it is necessary to control it in real time, and to use the measured one as a feedback for adjusting the e-beam current (higher currents correspond to higher rates).
In order to measure the evaporation rate a quartz microbalance is introduced as a controller. The device consists in a piezoelectric quartz crystal, vibrating at its background frequency. Specifically the oscillation frequency will drop as the crystal's mass is increased by the material being deposited on it. This correlation is used as a feedback towards the ebeam power supply to drive the current for regulating the rate.
The evaporated material diffuses into the deposition chamber following linear trajectories. This property imposes to handle n a well designed manner the substrates in order to expose them uniformely to the evaporation source. Typical substrate holders are rotating Domes (consisting in sections of a sphere) or Planetary carousels with double rotation.
In applications requiring a good adhesion and higher density coating, the evaporation system is also equipped with an Ion Gun. The Ion Gun is generating a plasma cone directed to the substrate. It can either be used for etching the substrate before the evaporation process (to improve the adhesion) or during it (for higher density).


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So What's Donald Trump Been Up To?
Whitney Kimball
PublishedFebruary 4, 2021
Photo: Win McNamee (Getty Images)
In the Federalist Papers in 1788, Alexander Hamilton forecast a grim future for former presidents stymied by term limits. Would they, now robbed of their presidential prospects, still be incentivized to "undertake extensive and arduous enterprises for the public benefit, requiring considerable time to mature and perfect them"? No—more likely they would loom around "wandering among the people like discontented ghosts, and sighing for a place which they were destined never more to possess."
In the case of Donald J. Trump, his post-term hobby of choice is, allegedly, writing out "insults and observations," and instructing other, not-yet-banned individuals to post them to Twitter. The Daily Beast reported on Monday:
But due to Twitter's banning of the @realDonaldTrump account following the Capitol riot that Trump instigated, he has not been able to personally trash [Republican Representative Liz] Cheney via his once widely read tweets. He has written out insults and observations, several of them about Cheney, but with no ability to tweet them himself, he has resorted to suggesting put-downs for others to use or post to their own Twitter, according to a person with direct knowledge of this new habit.
You know the guy has reams of material on Cheney and the nine other Republican representatives who voted in favor of impeaching him; he's got an encyclopedia of viciously demented racist conspiracy theories on tap courtesy of "star" ally Marjorie Taylor Greene.
It's dubious whether Trump has ever tried to undertake, or believed himself to be engaged in, "arduous enterprises for the public benefit" before or during his stay in the Oval. Rather than the office of the president, there's an argument to be made that Hamilton might instead have been describing the plight of the banned.
It's probably for the best that half the world isn't forced to care what pops into his head 30 times a day, though.
But if you were wondering, that's what he's up to: scrawling curses at Liz Cheney on Burger King wrappers, blowing through secret service members' burner accounts, sitting in the Big Chair behind a recreated Resolute Desk with a GHOSTWRITER FOR HIRE!!!! sign taped to it.
Gizmodo has reached out to Trump's team for further details on what he's been up to and will update the post if we hear back.

redpajama_set_name: RedPajamaCommonCrawl


combines the principle of ultraviolet UV with the principle of optics.
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gentle, clean water treatment device.
5, Suitable for beauty salons, home use.


Visit us to gain access to the most comprehensive C++ Beginners Guide. We have prepared this guide with the help of experts who has hands-on experience in working on C++. This easy to follow guide is the best tutorials available today to learn this program with enough examples.


Just a few minutes away from Raiatea's airport by shuttle boat, Taha'a "the Vanilla Island" has retained the charm of old-time Polynesia. The island is one giant colored and fragrant garden of which vanilla, the precious orchid, is the ruling princess. Taha'a produces more than 80% of the famous Tahitian vanilla, the favorite variety of true connoisseurs.
The huge lagoon of Taha'a possessed many motu, sandy islets on which you play Robinson Crusoe between dives. Prestigious hotels of exclusive luxury have chosen some of these isolated motu, perfect settings to fully taste the perfect calm of this authentic island.
An island with authentic charm: it is an untamed island with luxuriant vegetation, set in an emerald lagoon, ringed with idyllic motus.
Exotic tropical flora in splendid scented colorful gardens, with guided toursof vanilla plantations and tropical fruit during 4×4 safaris.
Discover the story of pearls on a guided tour of a family pearl farm.
A giant natural aquarium, the Tahaa lagoon is the place for magical dives where you can observe eels, gray sharks, napoleons, shoal of barracuda and amazing coral gardens.
Water activities: guided tours around the island in an outboard canoe; sumptuous picnics on a motu; feeding the rays and a visit to the dolphins; cruise onboard a yacht or catamaran in the crystalline waters of the lagoon.
Prestigious hotels offering exceptionally high standards of comfort combined with luxury, spaciousness and tradition. Refined cuisine and relaxing massages are offered in a charming setting.
Family hotels offer peace and a chance to discover the traditional way of life of the island's inhabitants.
Access by boat from Raiatea is ensured by regular daily shuttle speedboats.


Jesus, it's very comforting to know that you once said, "it is not the healthy who need a doctor but the sick." We confess that we are sick. Anxiety and anger weigh us down. Brokenness and bitterness paralyze our souls. Cynicism and criticism feel like givens. Our hearts, rarely at peace; our spirits, so easily crushed. Even when we laugh out loud there's this persistent unmistakable ache deep down that won't let us go. It's so easy to assume that even our times of rejoicing will somehow give way to grief.
We confess that we are sick. But as we do, we come to you, Jesus, master physician, suffering servant. You once declared, "a bruised reed I will not break and a smoldering wick I will not snuff out." What a relief! We beg you - heal our twisted, torn, always falling into temptation hearts. Bring life to these dry bones. Rescue us, redeem us and restore us, by your grace and for your glory. Amen.


LOUISVILLE, Ky. WDRB — A Louisville duo now holds a world record in bowling.
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both hope to set a further checklist quickly for probably the most finished video games bowled in 24 hours via a pair.
Reigning champion Jenny Wegner of Sweden holds the desirable section with 192, 300, 224, 227, 248 and 254 for a complete of 1."445 whereas Vanessa Timiter of Germany scored 1."389 on 230, 236, 225, 184, 227 and 237 for second.
Filipino kegler Jomar Jumapao is in nineteenth position in the men's division.
He submitted 1."237 on 202, 205, 208, 189, 233 and 200 – 196 pins at the back of match leader Arturo Estrada of Mexico, who posted 1,433 220, 247, 232, 226, 250 and 258.
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The top 24 gamers after 4 blocks will improve to the subsequent round.
The Philippines has 5 titles in the men's classification and two crowns within the ladies's class.
hall of Famer Paeng Nepomuceno dominated right here variants of the meet: 1976 in Tehran, Iran, 1980 in Jakarta, Indonesia, 1992 in Le Mans, France and 1996 in Belfast, Northern ireland, to grasp the Guinness World listing of profitable titles in three different many years.
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Christian Jan Suarez become the ultimate Filipino world champion, profitable in 2003 in Tegucigalpa, Honduras.
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Filipino Ruben Gonzales and American partner Hunter Reese have been booted out of competition within the doubles play of the 2017 Hyogo Noah ATP Challenger Tour on Tuesday in Kobe, Japan.
Gonzales and Reese misplaced to chinese Gong Mao-Xin and Taiwanese Peng Hsien-Yi, three-6, four-6, in the opening round.
The Davis Cup veteran will now proceed to India to compete in an additional ATP Challenger at the side of compatriot Francis Casey Alcantara.
Sivley talked about he has skilled a wide array of feelings when you consider that getting to know of his first-ever umpiring look on the Little League World collection.


In a church one morning, a preschooler left the pew to sit right in front of the pulpit, seeming to hang on every word of the Gospel in the way of people captivated by Jesus' preaching. Back in Jesus' time on Earth, a blind man's shouting to get His attention or the sight of Zacchaeus climbing a tree to see Him may have seemed childish to bystanders, and yet the Lord responded to both. In a parable of servants given gold coins to use in the master's absence, one servant hid the coin in fear of losing it. When we see ways to get closer to the Lord, do we let what other people might think or other fears get in the way of behaving as His children?


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Justia Patents Using Surface Acoustic WavesUS Patent Application for BOUNDARY ACOUSTIC WAVE ELEMENT, BOUNDARY ACOUSTIC WAVE DEVICE, AND MANUFACTURING METHODS FOR THE SAME Patent Application (Application #20090201102)
BOUNDARY ACOUSTIC WAVE ELEMENT, BOUNDARY ACOUSTIC WAVE DEVICE, AND MANUFACTURING METHODS FOR THE SAME
Apr 23, 2009 - Murata Manufacturing Co., Ltd.
A boundary acoustic wave element includes an IDT electrode arranged at the interface between a piezoelectric substance and a dielectric layer, a heat dissipation film is arranged on the outer side surface of the dielectric layer or on the outer side surface of a sound-absorbing film laminated on the outer side of the dielectric layer, the heat dissipation film is arranged to have a portion that overlaps the IDT electrode in plan view, and the heat dissipation film is connected to a bump provided on the outer side surface of the sound-absorbing film, and is connected to a via-hole conductor that extends through the sound-absorbing film. The boundary acoustic wave element and a boundary acoustic wave device are excellent in a heat dissipation property and hence can provide enhanced electric power resistance, without causing an increase in chip size and an increase in the area of the mounting space.
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The present invention relates to a boundary acoustic wave element and a boundary acoustic wave device which are used in resonators and band-pass filters, for example, and manufacturing methods for the same. More specifically, the present invention relates to a boundary acoustic wave element and a boundary acoustic wave device which are provided with a heat dissipation structure, and manufacturing methods for the same.
Recently, surface acoustic wave filter devices are widely used as band-pass filters in the RF stage of mobile telephones. High electric power resistance is significantly demanded for this type of band-pass filters.
Accordingly, Japanese Unexamined Patent Application Publication No. 2006-14096 proposes a structure which quickly releases heat generated when large electric power is applied to an IDT electrode, thereby suppressing migration of the IDT electrode and enhancing electric power resistance.
In a surface acoustic wave device described in Japanese Unexamined Patent Application Publication No. 2006-14096, a surface acoustic wave element is mounted on the upper surface of a circuit board, and the periphery of the surface acoustic wave element is sealed with molding resin. In the above-mentioned surface acoustic wave element, a functional electrode portion including the IDT electrode is formed on one principal surface of a piezoelectric substrate. A grounding annular electrode is formed so as to surround this functional electrode portion.
The above-mentioned surface acoustic wave element is mounted on the upper surface of the circuit board in such a way that its one principal surface side where the above-mentioned functional electrode portion and the grounding annular electrode are formed is opposed to the upper surface of the circuit board. The grounding annular electrode is electrically connected to a through-conductor provided so as to extend through the circuit board from the upper surface to the lower surface, and the through-conductor is electrically connected to a grounding conductor provided on the lower surface of the circuit board.
In this structure, the grounding annular electrode is electrically connected to a portion of the functional electrode portion including the IDT electrode which is connected to the ground potential. Therefore, heat generated in the IDT electrode is readily released to the exterior through the grounding annular electrode, the through-conductor, and the grounding conductor. Thus, an adverse influence due to heat is suppressed, making it possible to enhance electric power resistance.
Recently, on the other hand, boundary acoustic wave devices are attracting attention instead of surface acoustic wave devices. In surface acoustic wave devices, a space for vibrations of a portion where the IDT electrode is arranged must be provided within the package. In contrast, such a space can be omitted in the boundary acoustic wave devices. Thus, the boundary acoustic wave devices are small-sized.
FIG. 11 is a schematic front sectional view showing an example of a boundary acoustic wave device according to the related art.
A boundary acoustic wave element 501 has a piezoelectric substance 502. An IDT electrode 504, and reflectors 505 and 506 are formed on the upper surface of the piezoelectric substance 502. A dielectric substance 503 is laminated on the upper surface of the piezoelectric substance 502. That is, a functional electrode portion including the IDT electrode 504 is disposed at the interface between the piezoelectric substance 502 and the dielectric substance 503. A sound-absorbing layer 507 is provided on the dielectric substance 503. The sound-absorbing layer 507 is provided to absorb bulk waves that have propagated to the upper surface side of the dielectric substance 503, and suppresses unwanted spurious response.
In the case of the boundary acoustic wave element 501 as well, heat is generated in the functional electrode portion including the IDT electrode 504 when in actual use. Thus, there is a fear that migration of the IDT electrode or the like may occur due to this heat, causing electric power resistance to be decreased.
Therefore, it is considered desirable that the boundary acoustic wave element 501 also be provided with a heat dissipation structure such as one described in Japanese Unexamined Patent Application Publication No. 2006-14096.
However, in the case where the heat dissipation structure described in Japanese Unexamined Patent Application Publication No. 2006-14096 is adopted for the boundary acoustic wave element 1, the boundary acoustic wave element becomes large. Thus, the advantage of the boundary acoustic wave element, namely that it allows miniaturization, is greatly impaired. That is, in the heat dissipation structure described in Japanese Unexamined Patent Application Publication No. 2006-14096, the grounding annular electrode is arranged to surround the functional electrode portion including the IDT electrode. Accordingly, to provide a grounding annular electrode in the boundary acoustic wave element 501, naturally, on the upper surface of the piezoelectric substance 2, the grounding annular electrode must be formed in the peripheral region including the functional electrode portion such as the IDT electrode 504. Thus, the area of the above-mentioned boundary interface becomes large, that is, the plan area of the boundary acoustic wave element 501 becomes large, leading to an inevitable increase in mounting space.
In a case where the above-mentioned grounding annular electrode is provided in the boundary acoustic wave element 501, it is necessary to provide a connecting conductor for leading out the grounding annular electrode to the lower surface of the piezoelectric substance 502, or to the outer side surfaces of the dielectric substance 503 and sound-absorbing layer 507, which adds complexity to the structure of the boundary acoustic wave element 501 and also leads to high manufacturing cost.
Preferred embodiments of the present invention overcome the problems of the related art, and provide a boundary acoustic wave element equipped with a structure that makes it possible to quickly dissipate heat generated in an IDT electrode to enhance electric power resistance without enlarging a mounting space or mounting structure, and also provide a boundary acoustic wave device using the boundary acoustic wave element, and manufacturing methods for the same.
A boundary acoustic wave element according to a preferred embodiment of the present invention relates to a boundary acoustic wave element including a piezoelectric substance, a dielectric substance laminated on the piezoelectric substance, an IDT electrode disposed at an interface between the piezoelectric substance and the dielectric substance, and a sound-absorbing film provided on a surface of the dielectric substance opposite to the interface, the boundary acoustic wave element using a boundary acoustic wave that propagates along a boundary between the piezoelectric substance and the dielectric substance, characterized in that the boundary acoustic wave element further includes a heat dissipation pattern which is provided on an external surface of the dielectric substance or the sound-absorbing film and which has a portion that overlaps the IDT electrode in a plan view, the boundary acoustic wave element preferably further includes a bump provided on an outer side surface of the sound-absorbing film, and a via-hole conductor that extends through the sound-absorbing film and is electrically connected to the IDT electrode and the bump, and the bump and the heat dissipation pattern are connected to each other by the via-hole conductor. Preferably, the heat dissipation pattern is made of a metal or an alloy with a thermal conductivity of about 20 W/(m·K) or more, thereby making it possible to quickly dissipate heat generated in the IDT electrode.
Although the above-mentioned metal is not particularly limited, preferably, a metal selected from the group consisting of Al, Cu, Ni, and Cr, or an alloy mainly including the metal is used, for example. In that case, since these kinds of metal or alloy are superior in thermal conductivity, heat can be quickly dissipated.
In the boundary acoustic wave element according to a preferred embodiment of the present invention, a substantially center portion of the heat dissipation pattern is preferably connected to the via-hole conductor. In this case, since the portion of the heat dissipation pattern which is connected to the via-hole conductor is substantially the center portion of the heat dissipation pattern, the distance between the via-hole conductor and the farthest portion of the heat dissipation pattern becomes small, and heat is thus quickly dissipated. In this case, more preferably, a cross-sectional area of the via-hole conductor is set equal to or greater than a cross-sectional area of the IDT electrode. Thus, heat is quickly dissipated through the via-hole conductor.
A boundary acoustic wave device according to a preferred embodiment of the present invention includes the boundary acoustic wave element configured in accordance with another preferred embodiment of the present invention, a mounting substrate on which the boundary acoustic wave element is mounted, and a sealing resin that seals the boundary acoustic wave element mounted on the mounting substrate, and is characterized in that a thermal conductivity of the sealing resin is equal to or higher than about 0.8 W/(m·K).
A manufacturing method for a boundary acoustic wave element according to a preferred embodiment of the present invention includes the steps of: forming an IDT electrode on a mother piezoelectric substance; forming a dielectric layer to cover the IDT electrode; forming a sound-absorbing film on the heat dissipation pattern, on an upper surface of the dielectric layer; forming the heat dissipation pattern, which is shaped to have a portion that overlaps the IDT electrode in plan view, on the dielectric layer or the sound-absorbing film; forming an opening that extends through the sound-absorbing film; and cutting the mother piezoelectric substance into discrete boundary acoustic wave elements.
A manufacturing method for a boundary acoustic wave device according to a preferred embodiment of the present invention includes the steps of: preparing an assembly plate; forming a land arranged to mount a boundary acoustic wave element, on an upper surface of the assembly plate; mounting a plurality of the boundary acoustic wave elements by flip-chip bonding, so that the bump is joined to the land on the assembly plate; sealing the plurality of boundary acoustic wave elements mounted on the assembly plate with a sealing resin to form a plurality of resin-sealed members; detaching the resin-sealed members from the assembly plate; forming an opening in the resin-sealed members so as to expose a portion of the heat dissipation pattern; preparing a mounting substrate having in a mounting region an opening of substantially the same size as the opening in the resin-sealed members; joining the resin-sealed members onto the mounting substrate so that the opening in the resin-sealed members coincides with the opening in the mounting substrate coincides; and filling a conductive paste in the opening in the resin-sealed members and in the opening in the mounting substrate.
In a manufacturing method for a boundary acoustic wave device according to a preferred embodiment of the present invention, in the step of forming an opening in the resin-sealed members to expose a portion of the heat dissipation pattern, the opening is preferably formed so that a central portion of the heat dissipation pattern is exposed, and the opening in the mounting substrate is provided at a central portion of the mounting region. In this case, since a conductor formed by filling a conductive paste in the openings in the resin-sealed members and the mounting substrate is joined to the central portion of the heat dissipation pattern, heat can be dissipated more quickly.
In the boundary acoustic wave element according to a preferred embodiment of the present invention, in the laminate structure of the piezoelectric substance, the IDT electrode, the dielectric substance, and the sound-absorbing film, the heat dissipation pattern is provided on the outer side surface of the dielectric substance or the sound-absorbing film, the heat dissipation pattern has a portion that overlaps the IDT electrode in plan view, and the heat dissipation pattern is electrically connected to the bump by the via-hole conductor. Therefore, when heat generated in the IDT electrode is transmitted to the heat dissipation pattern, the heat can be quickly released to the bump through the via-hole conductor.
Thus, not only is heat released by the above-mentioned route passing through the IDT electrode, the via-hole conductor, and the bump, but heat is also released by a route passing through the heat dissipation pattern, the via-hole conductor, and the bump. Accordingly, the heat dissipation property is enhanced, thereby making it possible to enhance electric power resistance.
Moreover, the via-hole conductor and the bump provided on the above-mentioned sound-absorbing film are indispensable components for establishing electrical connection with the IDT electrode and the like, and since heat generated in the above-mentioned dissipation pattern can be released by using the via-hole conductor and the bumps that are such indispensable components, it is possible to enhance the heat dissipation property without causing an increase in chip size.
Thus, the structure of the boundary acoustic wave element is unlikely to become complex, and it is possible to provide a small-sized boundary acoustic wave element having an excellent heat dissipation property, without causing a significant increase in the cost of the boundary acoustic wave element.
In the boundary acoustic wave device according to a preferred embodiment of the present invention, the boundary acoustic wave element according to a preferred embodiment of the present invention is mounted on the mounting substrate, a sealing resin that seals the boundary acoustic wave element mounted on the mounting substrate is provided, and the thermal conductivity of the sealing resin is set to about 0.8 W/(m·K) or more. Thus, heat generated in the boundary acoustic wave element is quickly dissipated to the above-mentioned bump. At this time, the heat is quickly dissipated to the outer surface of the boundary acoustic wave device through the sealing resin in the periphery of the bump. Therefore, it is possible to provide a boundary acoustic wave device having an excellent heat dissipation property and excellent electric power resistance.
In a manufacturing method for a boundary acoustic wave element according to a preferred embodiment of the present invention, when forming an IDT electrode on a mother piezoelectric substance, forming a dielectric layer, and forming a sound-absorbing film on an upper surface of the dielectric layer, the boundary acoustic wave element according to a preferred embodiment of the present invention can be obtained simply by forming the heat dissipation pattern on the dielectric layer or on the sound-absorbing film, and cutting the mother dielectric substance member into discrete boundary acoustic wave elements. Therefore, it is possible to provide the boundary acoustic wave element according to a preferred embodiment of the present invention that is excellent in a heat dissipation property in a stable manner, without going through complicated steps.
In the manufacturing method for a boundary acoustic wave device according to a preferred embodiment of the present invention, the boundary acoustic wave device according to a preferred embodiment of the present invention can be obtained simply by forming a land on the assembly plate, mounting the boundary acoustic wave device by flip-chip bonding, sealing the boundary acoustic wave element with a sealing resin to form a resin-sealed member, detaching the resin-sealed member from the assembly plate, forming an opening in the resin-sealed member to expose a portion of the heat dissipation pattern, joining the resin-sealed member onto the mounting substrate so that the opening in the resin-sealed member is located at the opening in the mounting substrate, and filling a conductive paste in the openings of both the resin-sealed member and the mounting substrate. Therefore, it is possible to provide the boundary acoustic wave device having an excellent heat dissipation property in a stable manner, without causing an increase in chip size.
Other features, elements, steps, characteristics and advantages of the present invention will become more apparent from the following detailed description of preferred embodiments of the present invention with reference to the attached drawings.
FIG. 1 is a front sectional view of a boundary acoustic wave element according to a first preferred embodiment of the present invention.
FIGS. 2A and 2B are respectively a front sectional view of a boundary acoustic wave device according to the first preferred embodiment, and a sectional view taken along the line A-A in FIG. 2A.
FIG. 3 is a front sectional view of a boundary acoustic wave element according to a second preferred embodiment of the present invention.
FIGS. 4A and 4B are respectively a front sectional view of a boundary acoustic wave device according to the second preferred embodiment, and a sectional view taken along the line B-B in FIG. 4A.
FIGS. 5A and 5B are respectively a front sectional view of a boundary acoustic wave device according to a third preferred embodiment, and a sectional view taken along the line C-C in FIG. 5A.
FIGS. 6A to 6F are front sectional views showing an example of manufacturing method for a boundary acoustic wave device according to the third preferred embodiment of the present invention.
FIGS. 7A to 7F are front sectional views showing another example of manufacturing method for a boundary acoustic wave device according to the third preferred embodiment of the present invention.
FIGS. 8A and 8B are respectively a front sectional view of a boundary acoustic wave device according to a fourth preferred embodiment, and a sectional view taken along the line D-D in FIG. 8A.
FIG. 9 is a front sectional view of a boundary acoustic wave device according to a fifth preferred embodiment of the present invention.
FIG. 10 is a diagram showing variations in the highest temperature within a chip in a case where the thermal conductivity of a heat dissipation film is varied in the boundary acoustic wave device according to the first preferred embodiment of the present invention.
FIG. 11 is a front sectional view showing an example of a boundary acoustic wave device according to the related art.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
Hereinbelow, specific preferred embodiments of the present invention will be described with reference to the drawings to clarify the present invention.
FIG. 1 is a schematic front sectional view showing a boundary acoustic wave element according to a first preferred embodiment of the present invention.
A boundary acoustic wave element 1 has a piezoelectric substrate 2 as a piezoelectric substance. The piezoelectric substrate 2 is made of a piezoelectric single crystal such as LiNbO3, for example. However, the piezoelectric substrate 2 may be made of a piezoelectric material other than a piezoelectric single crystal.
A dielectric layer 3 is provided on one principal surface of the piezoelectric substrate 2. The dielectric layer 3 is made of SiO2 in this preferred embodiment. Electrode pads 5 and 6 are arranged at the interface between the piezoelectric substrate 2 and the dielectric layer 3. The IDT electrode 4 defines a functional electrode portion at the time when a boundary acoustic wave element is driven. A functional electrode portion indicates an electrode that functions to provide desired characteristics at the time when a boundary acoustic wave element is exited, and broadly includes an electrode portion that functions as a reflector, a capacitance, an inductance, or a resistor, other than the IDT electrode. The electrode pads 5 and 6 are electrically connected to a portion of the functional electrode portion which is connected to the ground potential.
The IDT electrode 4 and the electrode pads 5 and 6 are preferably formed by patterning a film made of a suitable metal or alloy on one principal surface of the piezoelectric substrate 2. In the boundary acoustic wave element 1, by exciting the IDT electrode 4, boundary acoustic waves are excited, and electrical characteristics using the boundary acoustic waves are extracted. The boundary acoustic waves propagate along the interface between the piezoelectric substrate 2 and the dielectric layer 3.
On the other hand, a sound-absorbing film 7 is laminated on the outer side surface of the dielectric layer 3. The sound-absorbing film 7 is made of a suitable material in which the sound velocities of longitudinal and transverse waves are lower than the sound velocities of longitudinal and transverse waves in the dielectric layer 3. Although not particularly limited, synthetic resin such as polyimide or epoxy resin, for example, can be suitably used as such a material. In this preferred embodiment, the sound-absorbing film 7 is preferably made of polyimide, for example.
Since the sound velocities of longitudinal and transverse waves in the sound-absorbing film 7 are lower than the sound velocities of longitudinal and transverse waves in the dielectric layer 3, in the sound-absorbing film 7, modes that become spurious response which have been propagated from the dielectric layer 3 side are attenuated, thereby making it possible to minimize a reflection of the modes that will be a spurious response toward the boundary between the piezoelectric substrate 2 and the dielectric layer 3. That is, by the sound-absorbing characteristics, undesired spurious responses are suppressed.
Via-hole conductors 8 and 9 are arranged to extend through the dielectric layer 3 and the sound-absorbing film 7. The via-hole conductors 8 and 9 can be made of a suitable metal such as solder, for example.
The via-hole conductors 8 and 9 are electrically connected to the electrode pads 5 and 6.
One of the unique features of this preferred embodiment is a heat dissipation pattern 10 on the outer surface of the dielectric layer 3. The heat dissipation pattern 10 is arranged on the outer surface of the dielectric layer 3, and is electrically connected to the via-hole conductors 8 and 9. The heat dissipation pattern 10 is made of a material including a metal or an alloy, for example, which has an excellent heat dissipation property. Al, Cu, or Ni, or an alloy of these is suitably used as such a material, for example, and examples of such an alloy include AlCu and NiCr, for example. These kinds of metal or alloy have high thermal conductivities of 20 W/m·K or more, and are thus excellent in a heat dissipation property as will be described later.
As seen in plan view of the boundary acoustic wave element 1, the heat dissipation pattern 10 partially overlaps the IDT electrode 4. That is, the heat dissipation pattern 10 is disposed below the functional electrode portion including the IDT electrode 4 of the boundary acoustic wave element 10.
While the grounding annular electrode described in Japanese Unexamined Patent Application Publication No. 2006-14096 described above is arranged to surround the functional electrode portion, the heat dissipation pattern 10 according to this preferred embodiment is provided at a position overlapping the functional electrode portion. Therefore, the heat dissipation pattern 10 can be formed without increasing the plan area of the boundary acoustic wave element 1. This makes it possible to enhance the heat dissipation property without causing an increase in the size of the boundary acoustic wave element 1, that is, without causing an increase in mounting space. The via-hole conductors 8 and 9 are electrically connected to bumps 11 and 12. That is, the bumps 11 and 12 are arranged on the via-hole conductors 8 and 9.
As mentioned above, the heat dissipation pattern 10 is preferably made of a material having excellent thermal conductivity, and is connected to the via-hole conductors 8 and 9. Upon exiting the boundary acoustic wave element 1, heat is generated in the IDT electrode 4. This heat is transmitted to the electrode pads 5 and 6 electrically connected to a portion of the functional electrode portion including the IDT electrode 4 which is connected to the ground potential. Since the via-hole conductors 8 and 9 are connected to the electrode pads 5 and 6, this heat is released toward the bumps 11 and 12 through the via-hole conductors 8 and 9.
Moreover, since the heat dissipation pattern 10 is arranged immediately below the IDT electrode 4, when heat generated in the IDT electrode 4 is transmitted to the heat dissipation pattern 10 through the dielectric layer 3, this heat is released to the bumps 11 and 12 through the via-hole conductors 8 and 9 from the heat dissipation pattern 10.
Therefore, heat generated in the IDT electrode 4 can be quickly dissipated through the above-mentioned two routes. This makes it possible to suppress migration and enhance electric power resistance.
Next, a description will be given of preferred embodiments of a manufacturing method for the boundary acoustic wave element 1, and a manufacturing method for a boundary acoustic wave device using the boundary acoustic wave element 1 and its structure.
In the manufacturing method for the boundary acoustic wave element 1, first, a piezoelectric substrate is prepared, and the IDT electrode 4 and the electrode pads 5 and 6 are formed by photolithography or the like on the mother piezoelectric substrate. Thereafter, the dielectric layer 3 is formed by depositing a SiO2 film on one principal surface of the piezoelectric substrate 2 that is a mother substrate. Next, a plurality of through-holes is formed on the dielectric layer 3 so that the electrode pads 5 and 6 are exposed. Thereafter, the heat dissipation pattern 10 is formed on the outer surface of the dielectric layer 3 by photolithography. Then, after forming the heat dissipation pattern 10, the sound-absorbing film 7 is formed by applying polyimide by spin coating or the like, for example.
Next, openings are formed in portions where the via-hole conductors 8 and 9 are to be formed by photolithography and etching. Then, the openings are plated with Ni and Au, for example, and a plated film as an under-bump metal layer is formed on the electrode pads 5 and 6 and the surface of the heat dissipation pattern 10 which is exposed through the openings. Thereafter, a conductive paste is filled in the openings, forming the via-hole conductors 8 and 9. The conductive paste consists of a suitable conductive paste such as a solder paste, for example. The via-hole conductors 8 and 9 are formed by the conductive paste to be dried and cured.
Thereafter, a conductive paste such as a solder paste is further applied onto the via-hole conductors 8 and 9, forming the bumps 11 and 12. Next, a structure in which a plurality of boundary acoustic wave elements obtained in the above-mentioned manner are put together on the mother piezoelectric substrate is cut into discrete boundary acoustic wave elements, thereby obtaining the boundary acoustic wave element 1 shown in FIG. 1.
In this preferred embodiment, a boundary acoustic wave device 21 shown in FIG. 2A is manufactured by using the boundary acoustic wave element 1 obtained as mentioned above.
In the boundary acoustic wave device 21, the boundary acoustic wave element 1 is mounted on a mounting substrate 22, and is sealed with a sealing resin 23.
In the manufacturing process, first, an assembly plate is prepared. Although not particularly limited, a plate-shaped member made of a hard material having excellent dimensional stability such as metal is preferably used as the assembly plate. A land arranged to mount the boundary acoustic wave element 1 is formed on the upper surface of this assembly plate. This land is located in correspondence to electrode lands provided on the mounting substrate 22. Then, the boundary acoustic wave element 1 is mounted by flip-chip bonding so as to be joined to the land on the assembly plate.
Thereafter, a plurality of the boundary acoustic wave elements 1 mounted on the assembly plate are sealed with the sealing resin 23. In this manner, a large number of resin-sealed members 24 are formed on the assembly plate from the boundary acoustic wave element 1 and the sealing resin 23 shown in FIG. 2A. The resin material forming the above-mentioned sealing resin 23 is not particularly limited as long as the material has an insulating property. As such a resin material, for example, a thermosetting resin composition including epoxy resin and a curing agent is preferably used.
Preferably, since an inorganic filler is superior in thermal conductivity to synthetic resin, it is desirable that an inorganic filler be contained in the above-mentioned thermosetting resin composition. As such an inorganic filler, carbon, silica, tungsten, or the like is preferably used, for example. When an inorganic filler is contained, it is possible to control the flowability in the thermosetting process performed by heating, and enhance the strength and dimensional stability of a cured product obtained after the curing. In addition, since the inorganic filler is excellent in thermal conductivity, the heat dissipation effect can be enhanced. That is, heat generated in the IDT electrode 4 can be dissipated to the exterior also from the sealing resin 23, thereby making it possible to further enhance a heat dissipation property.
Therefore, more preferably, it is desirable that the sealing resin 23 be formed by a thermosetting resin composition containing the above-mentioned inorganic filler, which is superior in thermal conductivity to synthetic resin, as much as possible, and it is desirable that the content of the inorganic filler be set high at, for example, about 80 weight percent or more, for example.
After a plurality of the resin-sealed members 24 are formed on the assembly plate as mentioned above, the resin-sealed members 24 are detached from the assembly plate. Thereafter, the resin-sealed members 24 are mounted on the mounting substrate 22 shown in FIG. 2A preferably by flip-chip bonding. The mounting substrate 22 has electrode lands 25 and 26 formed on its upper surface. The bumps 11 and 12 are joined to the electrode lands 25 and 26.
The mounting substrate 22 is provided with via-hole conductors 27 and 28. The via-hole conductors 27 and 28 extend through the mounting substrate 22, and are connected to the electrode lands 25 and 26 at their upper ends. The lower ends of the via-hole conductors 27 and 28 are joined to terminal electrodes 29 and 30. The terminal electrodes 29 and 39 are formed on the lower surface of the mounting substrate 22.
Therefore, the boundary acoustic wave device 21 can be handled as a small electronic chip component in which the boundary acoustic wave element 1 is resin-sealed.
FIG. 2B is a schematic sectional view of the portion taken along the arrow A-A line in FIG. 2A. In this drawing, the positional relationship between the heat dissipation pattern 10 and the IDT electrode 4 located above the heat dissipation pattern 10 is schematically shown. That is, the heat dissipation pattern 10 is located directly below the IDT electrode 4, and is provided in a region overlapping the IDT electrode 4. Therefore, it can be seen that heat radiated downwards from the IDT electrode 4 is quickly released from the heat dissipation pattern 10.
FIG. 3 is a front sectional view showing a boundary acoustic wave element according to a second preferred embodiment of the present invention. In a boundary acoustic wave element 31 according to the second preferred embodiment, the heat dissipation pattern 10 is not provided on the outer surface of the dielectric layer 3. Instead, the heat dissipation pattern 10 is provided on the outer side surface of the sound-absorbing film 7 that is provided on the outside of the dielectric layer 3, and an insulating layer 32 is further provided on the outer side of the heat dissipation pattern 10. Then, to electrically connect the electrode pads 5 and 6 and the via-hole conductors 8 and 9 to each other, electrode films 33 and 34 are formed within through-holes formed in the dielectric layer 3. A portion of the heat dissipation pattern 10 is laminated on the electrode films 33 and 34, and the via-hole conductors 8 and 9 are formed thereon. Otherwise, the boundary acoustic wave element 31 preferably has the same structure as the boundary acoustic wave element 1.
The above-mentioned insulating layer 32 is made of a suitable insulating material, and is formed by spin-coated synthetic resin such as polyimide, for example, in this preferred embodiment. The heat dissipation pattern 10 can be protected by providing the insulating layer 32 as described above. The insulating layer 32 may also be used as a solder resist when forming the via-hole conductors 8 and 9 and the bumps 11 and 12. That is, an insulating layer may be formed as a solder resist to be used for forming the via-hole conductors 8 and 9 and the bumps 11 and 12, and the insulating layer may be kept to be the insulating layer 32.
In the boundary acoustic wave element 31 according to this preferred embodiment as well, not only is the heat generated in the IDT electrode 4 be dissipated to the external from the electrode pads 5 and 6 through the electrode films 33 and 34 by the route of the via-hole conductors 8 and 9 and then the bumps 11 and 12, but since the heat dissipation pattern 10 is located directly below the IDT electrode 4, that is, to overlap the IDT electrode 4, and the heat dissipation pattern 10 is connected to the via-hole conductors 8 and 9, heat that has been transmitted to the heat dissipation pattern 10 from the IDT electrode 4 through the dielectric layer 3 is also quickly dissipated.
Therefore, according to the second preferred embodiment as well, a heat dissipation property can be enhanced, which in turn makes it possible to enhance electric power resistance.
FIGS. 4A and 4B are schematic front sectional views of a boundary acoustic wave device 35 using the boundary acoustic wave element 31 according to the second preferred embodiment. That is, as in the boundary acoustic wave device 21 shown in FIG. 2, by sealing the boundary acoustic wave element 31 with the sealing resin 24 on the mounting substrate 22, the boundary acoustic wave device 35 having excellent environmental resistance characteristics and a small chip size can be provided. FIG. 4B is a schematic plan sectional view taken along the line B-B in FIG. 4A. As is clear from FIG. 4B, in this preferred embodiment as well, the heat dissipation pattern 10 is located in a region overlapping the IDT electrode 4.
Next, referring to FIGS. 5A and 5B, the structure of and manufacturing method for a boundary acoustic wave device according to a third preferred embodiment of the present invention will be described.
In the third preferred embodiment, the boundary acoustic wave element 41 is prepared in the same manner as in the first preferred embodiment. Next, as shown in FIG. 5A, an opening 7a is defined in the sound-absorbing film 7 made of polyimide, below the heat dissipation pattern 10. The opening 7a is arranged directly below the IDT electrode 4. That is, as shown in the sectional view of FIG. 5B taken along the line C-C in FIG. 5A, the large opening 7a is substantially located at the central portion of the heat dissipation pattern 10.
The opening 7a can be formed by photolithography. It is desirable that the opening 7a have a size greater than the area of a single IDT electrode 4a. Thus, as will be described later, heat can be quickly released from the heat dissipation pattern 10 by a via-hole electrode described later which is formed in the opening 7a.
Next, the boundary acoustic wave element 1 is mounted on an unillustrated assembly plate made of metal. Lands made of Cu or the like are arranged on the surface of this assembly plate in advance, and the bumps 11 and 12 of the boundary acoustic wave element 1 are joined onto the lands.
Thereafter, the periphery of the boundary acoustic wave element 1 is sealed with the sealing resin 23, forming a resin-sealed member 24A. Next, the resin-sealed member 24A is stripped from the above-mentioned assembly plate. In this case, the electrode lands and the like on the assembly plate are transferred to the resin-sealed member 24A side. In this manner, a conductor made of Cu provided on the above-mentioned assembly plate is transferred to the resin-sealed member 24A side as a portion of the via-hole conductor 43, and electrode lands 44 and 45 are also transferred.
Thereafter, the resin-sealed member 24A may be mounted on a mounting substrate 22A. The mounting substrate 22A is of the same structure as the mounting substrate 22 shown in FIG. 2A, except that the electrode lands 25 and 26 are not provided since the electrode lands 44 and 45 are arranged on the resin-sealed member 24A side in advance, and that a conductor made of Cu is filled in the relatively large opening arranged to define the via-hole conductor 43. Therefore, the resin-sealed member 24A is mounted to the mounting substrate 24A in such a way that the opening 7a of the above-mentioned resin-sealed member 24A coincides with the relatively large opening that is provided at the center of the mounting region of the mounting substrate 24A and has the conductor made of Cu filled therein. Thus, the conductor portion made of Cu within the opening 7a, and the conductor portion made of Cu within the opening of the mounting substrate 22A are joined together, defining the via-hole conductor 43. In this manner, the boundary acoustic wave device 41 according to this preferred embodiment can be obtained.
In this preferred embodiment, since the above-mentioned via-hole conductor 43 is joined to substantially the center of the heat dissipation pattern 10, heat is quickly transmitted to the via-hole conductor 43 from various regions of the heat dissipation pattern 10. Therefore, the heat dissipation property can be further enhanced.
The formation of the opening arranged to define the via-hole conductor 43 can be done by various methods. These methods will be described with reference to FIGS. 6A to 7F.
In a method shown in FIGS. 6A to 6F, the periphery of the boundary acoustic wave element 1 is coated with a sealing resin 51. Thereafter, the electrode lands 44 and 45 are formed on the lower surface of the sealing resin 51. Next, as shown in FIG. 6B, the opening 7a is formed. The formation of the opening 7a can be performed by a suitable method such as a method using a laser device such as a carbon dioxide gas laser or an excimer laser, or etching, for example.
Next, the mounting substrate 22A shown in FIG. 6C made of a resin sheet which defines a mounting substrate is bonded. The mounting substrate 22A has an opening 22a that is continuous to the opening 7a, and openings 22b and 22c smaller than the opening 22a. The openings 22b and 22c are provided at positions that overlap the electrode lands 44 and 45.
Although a sheet made of a suitable synthetic resin material can be used as the resin sheet for forming the above-mentioned mounting substrate 22A, preferably, a resin sheet made of a thermosetting resin composition is preferably used. As such a thermosetting resin sheet, an epoxy resin-based resin composition is preferably used, and more preferably, a thermosetting resin composition containing the above-described inorganic filler having excellent thermal conductivity is used.
Next, as shown in FIG. 6D, a conductive paste is filled in the openings 22a and 22c by screen printing or the like from the lower surface side of the mounting substrate 22A.
Thereafter, a metal foil 46 made of a Cu foil or the like is bonded onto the entire lower surface of the mounting substrate 22A. Thereafter, the mounting substrate 22A and the filled conductive paste are heated for curing. In this manner, the metal foil 46 is electrically and mechanically joined to the heat dissipation pattern 10 via via-hole electrodes made of a cured conductive paste.
Next, patterning is performed on the metal foil 46 by photolithography and etching, forming terminal electrodes 29, 30, and 47. The terminal electrodes 29, 30, and 47 are electrically connected to the via-hole electrodes 27 and 28, and the via-hole electrode 43, respectively.
Normally, the steps from FIGS. 6A to 6F are performed in the mother substrate state. The mother substrate may be cut into discrete boundary acoustic wave elements by using a dicer or the like at the end, for example.
As a second method, as shown in FIG. 7A, after stripping the above-described assembly plate from the resin-sealed member, the assembly plate is bonded to the mounting substrate 22A made of a resin sheet. Next, the opening 22a though which the wiring pattern 10 is exposed, and the openings 22b and 22c through which the electrode lands 44 and 45 are exposed are formed in the lower surface of the mounting substrate 22A (see FIG. 7B).
When forming the opening 22a, the opening 22a is drilled so as to become continuous to the opening 7a formed in the sound-absorbing film 7 above, thereby exposing the heat dissipation pattern 10.
Next, as shown in FIG. 7C, a conductive film 48 made of a Cu-plated film is formed by wet plating, for example, from the lower surface side of the laminated member so as to reach the inner surfaces of the above-mentioned openings 22a to 22c. Thereafter, as shown in FIG. 7D, after forming the conductive film 48, synthetic resin pastes 48a to 48c are filled in the openings 22a to 22c. Instead of the synthetic resin pastes 48a to 48c, insulating pastes made of other insulating materials may be used. However, preferably, it is desirable that a conductive paste with a high thermal conductivity be filled in the opening 22a at the center instead of the resin paste 48a.
Next, the above-mentioned resin pastes 48a to 48c are cured by heating. Thereafter, as shown in FIG. 7E, a conductive film 49 preferably made of a Cu-plated film is formed on the lower surface of the laminated member, that is, on the entire lower surface of the mounting substrate 22A. Next, patterning is applied to the conductive film 49 by photolithography or the like, forming the terminal electrodes 29, 30, and 47. By repeating the above resin-sheet laminating step and terminal electrode forming method, a plurality of wiring layers may be formed via two or more insulating layers made of a resin sheet.
In the second method as well, the steps from FIGS. 7A to 7F may be performed in the mother substrate state, and the mother substrate may be cut into discrete boundary acoustic wave elements by using a dicer at the end.
The synthetic resin material forming the resin sheet used in the first and second methods mentioned above is preferably the same resin material as that of the sealing resin of the boundary acoustic wave device. In that case, the thermal expansion coefficient of the resin sheet and the thermal expansion coefficient of the sealing resin become the same, making it possible to suppress distortion, peeling, and the like due to temperature variations. Further, if the materials are the same, the adhesion between the two materials increases, and intrusion of moisture or the like is less likely to occur.
FIGS. 8A and 8B are respectively a schematic front sectional view of a boundary acoustic wave device according to a fourth preferred embodiment, and a sectional view taken along the line D-D in FIG. 8A.
In a boundary acoustic wave device 51 according to the fourth preferred embodiment, an under-bump metal layer 52 is provided at the center of the lower surface of the heat dissipation pattern 10. The under-bump metal layer 52 is made of a laminated metal film formed by plating Ni and Au to thicknesses of about 3 μm or more and about 0.05 μm or more, respectively, for example. Such an under-bump metal layer 52 is formed in advance, and a solder paste is applied onto the under-bump metal layer 52, forming a bump 53. On the other hand, an electrode land 54 to which the bump 53 is to be joined is formed on the upper surface of the mounting substrate 22, and the bump 53 is joined to the electrode land 54. Otherwise, the boundary acoustic wave device 51 preferably has the same structure as the boundary acoustic wave device 21.
In this preferred embodiment as well, the heat dissipation pattern 10 is located below the IDT electrode 4, and heat generated in the IDT electrode 4 is also dissipated by a route passing through the heat dissipation pattern 10. In particular, since the bump 53 is provided on the lower surface of the heat dissipation pattern 10 through the under-bump metal layer 52, and the bump 53 is joined to the electrode land 54 on the mounting substrate 22, heat from the heat dissipation pattern 10 is also released by a route passing through the bump 53. Therefore, the boundary acoustic wave device 51 having an even more superior heat dissipation property and, therefore, superior electric power resistance, can be provided.
The material forming the bump 53 is not limited to a solder paste, and other kinds of conductive paste may be used, for example.
In this preferred embodiment, as shown in FIG. 8B, the position at which the bump 53 is formed is substantially the center of the heat dissipation pattern 10, which also helps to quickly release heat from the heat dissipation pattern 10 to the bump 53.
FIG. 9 is a front sectional view showing a boundary acoustic wave device according to a fifth preferred embodiment. In a boundary acoustic wave device 61, the IDT electrode 4 and the electrode pads 5 and 6 are arranged on the upper surface of a piezoelectric substrate 62 defining a piezoelectric substance. The piezoelectric substrate 62 is made of the same material as that of the piezoelectric substrate shown in FIG. 1.
A dielectric layer 63 preferably made of SiO2 is laminated on the piezoelectric substrate 62 so as to cover the IDT electrode 4. The heat dissipation pattern 10 is laminated on the upper surface of the dielectric layer 63. Openings for exposing the electrode pads 5 and 6 are defined in the dielectric layer 63, and the heat dissipation pattern 10 reaches inside the openings as well. The heat dissipation pattern 10 is electrically connected to the electrode pads 5 and 6. On the other hand, a sound-absorbing film 64 is laminated on the dielectric layer 63. The sound-absorbing film 64 is made of the same material as that of the sound-absorbing film 7 according to the first preferred embodiment. In this preferred embodiment, the sound-absorbing film 64 is preferably made of polyimide, for example.
In the sound-absorbing film 64, a relatively large opening 64a is formed at the center. The sound-absorbing film 10 below is exposed by the opening 64a. On the other hand, through-holes 64b and 64c, which are continuous to the openings provided in the dielectric layer 63 described above, are provided separately from the opening 64a.
The piezoelectric substrate 62 is bonded to a base plate 65 through an adhesive layer 66. The base plate 65 is made of suitable synthetic resin, metal, or ceramic. Then, the piezoelectric substrate 62 is joined to the base plate 65, and resin-sealing is performed with a sealing resin 67 to cover a structure in which the IDT electrode 4, the electrode pads 5 and 6, the dielectric layer 63, and the sound-absorbing film 64 are formed, thus obtaining a resin-sealed member 68. In the resin-sealed member 68, openings 68a to 68c are arranged in the upper surface side. The opening 68a is provided at a position overlapping the opening 64a to expose the heat dissipation pattern 10 below. The openings 68b and 68c are provided at positions overlapping the through-holes 64b and 64c described above. The formation of such openings 64a to 64c can be performed by any suitable method such as a machining method using laser, or etching, for example.
Thereafter, a conductive paste is filled in the openings 68a to 68c, and cured. In this manner, a metal conductor 69 is formed. A protective film 70 made of an insulating material is formed on the entire surface of the metal conductor 69. Next, a plurality of openings is defined in the protective layer 70, and bumps 71 and 72 connected to the metal conductor 69 below are formed. In this manner, the boundary acoustic wave device 61 is obtained.
In the boundary acoustic wave device 61 according to this preferred embodiment, the heat dissipation pattern 10 is provided at a position overlapping the IDT electrode 4, and heat generated in the IDT electrode 4 is dissipated by a route passing through the heat dissipation pattern 10. In particular, since the metal conductor 69 is provided so as to contact the IDT electrode 4, heat generated in the IDT electrode 4 is more quickly transmitted to the bumps 71 and 72, and the heat dissipation property can be effectively enhanced.
In this preferred embodiment, no via-hole electrode is arranged at a position vertically overlapping the region where the IDT electrode 4 is arranged. Therefore, since the location of bumps does not affect the location of the IDT electrode 4, it is possible to increase the freedom of location of bumps in the boundary acoustic wave device, and also increase the freedom of design of the IDT electrode 4.
The material forming the protective film 70 is not particularly limited, and a suitable insulating material such as polyimide can be used, for example. Also, in the above-described preferred embodiments, the conductive material defining the electrodes and bumps is not particularly limited, and various kinds of metal or alloy can be used.
Next, the material defining the heat dissipation pattern 10 in the boundary acoustic wave device 21 shown in FIG. 2 was changed, and the thermal conductivity of the heat dissipation pattern 10 was varied, and variations in the highest temperature within the boundary acoustic wave device 21 at the time of actual use were obtained. The results are shown in FIG. 10. The individual materials defining the boundary acoustic wave device 21 and their thermal conductivities were set as follows.
Piezoelectric substrate 2: LiNbO3 with a thickness of 150 μm, and thermal conductivity is 2.93 (W/(m·K))
IDT electrode 4: made of Au, 1 μm in thickness, and thermal conductivity=315 (W/(m·K))
Dielectric layer 3: SiO2, 6 μm in thickness, and thermal conductivity=1.18 (W/(m·K))
Sound-absorbing film 7: 6 μm in thickness, made of polyimide, and thermal conductivity=0.15 (W/(m·K))
Sealing Resin 23: A high thermal conductivity resin material of 40 μm in thickness with a thermal conductivity of 0.9 (W/(m·K)) including silica as an inorganic filler mixed in epoxy resin
Mounting substrate 22: a glass epoxy substrate, 1000 μm in thickness, and thermal conductivity=0.3 (W/(m·K))
Diameter of via-hole conductors=40 μm, thermal conductivity is 3 to 5 (W/(m·K))
Solder bumps 11 and 12: 40 μm in projection height, and thermal conductivity=40 (W/(m·K))
The heat dissipation film 10 was set to a thickness of about 5 μm, was defined by the various kinds of metal or alloy mentioned below, and its thermal conductivity was varied. The heating value of the IDT electrode 4 was set to about 0.1 W, and the ambient temperature was set to about 25° C., for example. The plan shape of the boundary acoustic wave element 1 was set approximately to a 1.8×0.8 mm rectangle, and the plan shape of the bumps 11 and 12 was set approximately to a square whose one side is about 100 μm in length. The results are shown in FIG. 10.
As is clear from FIG. 10, it can be seen that the higher the thermal conductivity of the heat dissipation pattern 10, the lower the highest temperature within the chip. In particular, it can be seen that if the thermal conductivity of the material defining the heat dissipation film 10 is about 20 W/(m·K)) or higher, the temperature within the chip can be made sufficiently low.
While preferred embodiments of the present invention have been described above, it is to be understood that variations and modifications will be apparent to those skilled in the art without departing the scope and spirit of the present invention. The scope of the present invention, therefore, is to be determined solely by the following claims.
1. A boundary acoustic wave element comprising:
a piezoelectric substance;
a dielectric substance laminated on the piezoelectric substance;
an IDT electrode disposed at an interface between the piezoelectric substance and the dielectric substance;
a sound-absorbing film provided on a surface of the dielectric substance opposite to the interface;
a heat dissipation pattern that is arranged on an outer side surface of the dielectric substance or the sound-absorbing film and has a portion that overlaps the IDT electrode when seen in a plan view;
a bump provided on an outer side surface of the sound-absorbing film; and
a via-hole conductor that extends through the sound-absorbing film, and is electrically connected to the IDT electrode and the bump; wherein
the bump and the heat dissipation pattern are connected to each other by the via-hole conductor; and
the boundary acoustic wave element using a boundary acoustic wave that propagates along a boundary between the piezoelectric substance and the dielectric substance.
2. The boundary acoustic wave element according to claim 1, wherein the heat dissipation pattern is made of a metal or an alloy having a thermal conductivity of about 20 W/(m·K) or more.
3. The boundary acoustic wave element according to claim 2, wherein the metal is made of a metal selected from the group of Al, Cu, Ni, Cr, or an alloy mainly including the metal.
4. The boundary acoustic wave element according to claim 1, wherein a substantially center portion of the heat dissipation pattern is connected to the via-hole conductor.
5. The boundary acoustic wave element according to claim 4, wherein a cross-sectional area of the via-hole conductor is equal to or greater than a cross-sectional area of the IDT electrode.
6. A boundary acoustic wave device comprising:
the boundary acoustic wave element according to claim 1;
a mounting substrate on which the boundary acoustic wave element is mounted; and
a sealing resin arranged to seal the boundary acoustic wave element mounted on the mounting substrate; wherein
a thermal conductivity of the sealing resin is equal to or higher than about 0.8 W/(m·K).
7. A manufacturing method for a boundary acoustic wave element, comprising the steps of:
forming an IDT electrode on a mother piezoelectric substance;
forming a dielectric layer to cover the IDT electrode;
forming a sound-absorbing film on the heat dissipation pattern, on an upper surface of the dielectric layer;
forming the heat dissipation pattern, which is shaped to have a portion that overlaps the IDT electrode in plan view, on the dielectric layer or the sound-absorbing film;
forming an opening that extends through the sound-absorbing film; and
cutting the mother piezoelectric substance into discrete boundary acoustic wave elements.
8. A manufacturing method for a boundary acoustic wave device, comprising the steps of:
preparing an assembly plate;
forming a land arranged to mount a boundary acoustic wave element, on an upper surface of the assembly plate;
mounting a plurality of the boundary acoustic wave elements according to claim 1 by flip-chip bonding, so that the bump is joined to the land on the assembly plate;
sealing the plurality of boundary acoustic wave elements mounted on the assembly plate with a sealing resin to form a plurality of resin-sealed members;
detaching the resin-sealed members from the assembly plate;
forming an opening in the resin-sealed members to expose a portion of the heat dissipation pattern;
preparing a mounting substrate having in a mounting region an opening of substantially the same size as the opening in the resin-sealed members;
joining the resin-sealed members onto the mounting substrate so that the opening in the resin-sealed members coincides with the opening in the mounting substrate coincides; and
filling a conductive paste in the opening in the resin-sealed members and in the opening in the mounting substrate.
9. The manufacturing method for a boundary acoustic wave device according to claim 8, wherein:
in the step of forming an opening in the resin-sealed members to expose a portion of the heat dissipation pattern, the opening is formed so that a central portion of the heat dissipation pattern is exposed; and
the opening in the mounting substrate is provided at a central portion of the mounting region.
Applicant: Murata Manufacturing Co., Ltd. (Nagaokakyo-shi)
Inventor: Tetsuya Oda (Ishikawa-gun)
Current U.S. Class: Using Surface Acoustic Waves (333/193); Piezoelectric Device Making (29/25.35)
International Classification: H03H 9/64 (20060101); H01L 41/22 (20060101);


Recycling - Startup tips to help you succeed. Green your life today.
Recycling your waste is one of the absolute best ways to start greening your life, if you have been putting off doing so.
It saves the earth's resources by reusing materials. Recycling prevents dangerous chemicals from polluting rivers, soil and the air and reduces greenhouse gas emissions.
But there is something far more valuable and long lasting you will gain from recycling.
Recycling will change the way you think. Recycling will change how you choose and what you buy.
In the end, recycling will save you money.
Ready to give it a try? Here are some tips to get you started.
It might sound silly or obvious, but identify a space where all recycling has to go. Having a set space to take recycling to will immediately increase your chances at success.
Also remember: recycling is not just about sorting your waste. You also need to drop off recycled waste at a depot from where it can be processed. So ensure your space is somewhere you will remember to pick it up on your way out.
Collect waste in separate recycling containers. It can be anything from dedicated dustbins, to crates or used plastic shopping bags.
Try to set up containers in such a way that recycling gets deposited directly into the container that it is going to get disposed off in. So if you use a crate, line it with a plastic bag for easy pick up and go.
Word of advice: start with containers you already have in the house. Next, figure out how much recyclable waste your household generates and how often you dispose of recycled items. Once you have established quantities and schedule, you can invest in the right size and type of containers, if you need to.
Most things are easy to do … once. Doing it over and over again until it becomes a habit takes a little bit more effort.
So don't rush into it. Start with one (maximum two) items to recycle, for instance glass or paper. Only add more items once you have the habit properly formed and the details sorted.
Rome wasn't built in one day. Neither does your recycling effort have to be.
How do you decide which item to start recycle? Easy peasy.
Find the nearest, easiest recycling depot to your house and start with those materials.
Easy drop-off is half the battle won.
This can be a tricky one, depending on who you share your dwelling with. Recycling isn't difficult, but it requires commitment, and commitment, and more commitment.
Don't war. Don't blame. Don't shame.
Focus on the positives. Encourage. Celebrate small victories.
South Africans do not yet have a recycling culture or -laws, as some European and other countries, so it remains a largely voluntary act to recycle. And for voluntary acts you need volunteers.
Get it? Now get going. And if you mess up, don't fret. Reboot, simplify even more, and start again.


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The Playazo: is more than 2 kilometers long and a width of 50 meters, this beach is 1400 meters from the northern end and reserved for those practitioners of naturism. Vera is one of the places in the entire Spanish coastline with a big naturist tradition. It is ideal for surfing and sailing.
Puerto Rey: where the mouth of the Antas river forms a small lagoon which a large number and variety of birds use as a resting place on their migrations between Africa and Europe. It covers an area of over 2300 meters by 130 meters wide. It is an urban beach composed of darker sand and has lots of local amenities and services.


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Valuable Talk: Pandemic Can't Stop Tigist Reda from Serving Her Ethiopian Food to Chicago
December 2, 2020 at 7:00 am by Rebecca Holland
by Rebecca Holland
December 2, 2020 January 2, 2021 Filed under:
Tigist Reda
Tigist Reda, owner of Demera Ethiopian Restaurant, has been introducing Chicagoans to Ethiopian food and feeding repeat diners for thirteen years. That mission continues in 2020, but in a different form. Like most restaurants in Chicago and across the country, business is tough due to closures, and, one must assume, the hesitancy of many diners to sit down to dinner indoors alongside tables filled with strangers.
"It's been an interesting year," Reda says, "to say the least."
Reda is busier than ever with carryout orders while strategizing ways to get her food in front of diners. Reda hosted a pop-up in Bronzeville in August and September, where customers could order ahead of time and pick up their meals between 5pm and 7pm. This kind of outreach may be a useful approach to expanding the dining pool even in the future.
Through Let's Talk, a collaboration of women restaurateurs in Chicago, Reda participated in October's "Flavor," which presented four curated menus available for delivery on Tock. Demera's dishes were part of the "Savor the World" menu. Reda isn't sure what December will hold, but she anticipates more events, including a potential initiative around Black-owned restaurants, all of which could prove useful when the world changes.
"It has been awesome to collaborate with other women," says Reda of Let's Talk, which was founded by Vermilion owner Rohini Dey and includes chefs like Beverly Kim of Parachute and Wherewithall, Carrie Nahabedian of Brindille, Uzma Sharif of Chocolate Uzma, and Mary Aregoni of Saigon Sisters. The range of chefs and dining experiences suggests the broad appeal of Let's Talk. "We organize ourselves to help each other get through the winter months," she says.
Reda also hopes to forge collaborations with restaurateurs outside of Uptown, where Demera is based. A restaurant in Logan Square could serve her dishes, for example, and vice versa. This would not only be good for business, but it could expand dining options for consumers and expose more Chicagoans to Ethiopian food, and Reda sees an appetite for that.
If you haven't had Ethiopian food, it's one of Africa's more approachable cuisines, and the signature dish is a thin, flexible and soft "pancake" of teff, a traditional and gluten-free Ethiopian grass, mounted with colorful mounds of meat and vegetables, offering many textures and flavor combinations. Eating with the hands is typical in Ethiopia and other African countries, and although this may present a cultural barrier for Americans who don't usually eat—and don't know how to eat—without silverware, it's a fun experience. And if you don't find it so, silverware is available.
"Our clients used to be very young foodies, or people from the Ethiopian community," she says. "But now I see diverse diners, older people." Reda used to see older adults come in only with their grown children who wanted them to try her food. Now, she sees those in their sixties and seventies come in on their own or with friends. "People are becoming more comfortable with Ethiopian food. It's no longer so different, and people seem more willing to try things out," she says.
Since opening in 2007, Demera has become a Chicago staple, often cited as the best Ethiopian restaurant in Chicago and garnering rave reviews across review sites and in food publications.
Her customers have been loyal and supportive, ordering for carryout and delivery when they can. Prior to the pandemic, carryout was five percent of Demera's business. Now, it represents just about all of Demera's business, and this is a familiar story from many local restaurants. "Our food travels really well, and we've had families sending us pictures of them enjoying it at home, which is nice," says Reda, who grew up cooking with the women in her own family in Ethiopia.
Demera has a few outdoor tables, but with winter approaching they'll soon be put away for the season. And as supportive as customers want to be, there's only so long carryout can sustain a full-service restaurant. Reda says the main lesson she's learned over the years is the power of resilience. "So much has changed. The recession, harsh winters, and now this. You learn to work through it."
The capacity to overcome difficulties is testing every restaurant owner in the city in 2020. Reda, through will and partnerships with the women of Let's Talk, is doing everything she can to emerge not just in one piece, but more resilient and with a wider group of devoted diners than ever before.
Oh! What a Lovely Pandemic: What Doesn't Kill Us No one is going to say that the pandemic was a "good thing," but like war and other catastrophes, it's possible to see that some good has—and will—emerge from this international disaster.
Strategies for Staying Afloat: Amy Morton Positions Her Restaurants to Survive the Pandemic Amy Morton opened Aurora's Stolp Island Social on the last day of November, 2019, just down Galena street from the Copley and Paramount Theaters and near the Riverfront Playhouse. The idea was to create a restaurant that would provide the first half of the traditional "dinner and a show" date. Then…well, you know what happened.
Demera Ethiopian Restaurant
Uzma Sharif
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