The quintessential tree-hugger, Seattle-mobile? A truly off-road capable cross-over? A luxo-wagon? What is this thing? Probably all of those.
The 2015 Subaru Outback is all-new and has grown up since the first day we laid our eyes on the somewhat ungainly, difficult-to-explain but likable tall wagon. Not only has it grown up, it's also become significantly pricier.
While there's a touch of sticker shock at first glance, you do get a lot of car for your money here. Bear with me.
It seems that Subaru is sticking with some old school stuff in the engine bay. The upper trims for the Outback feature the 3.6-litre 6-cylinder horizontally-opposed engine. Numbers aren't too exciting by today's standards. 256 horsepower at 6000 RPM and 247 lb.ft of torque at 4400 RPM. The boxer engine sends its thrills through a high-torque CVT (continuously-variable transmission) to all four corners via Subi's outstanding symmetrical all-wheel drive.
A relatively big displacement engine, shlepping a tall 3845 pound all-wheel drive wagon around isn't going to set any fuel economy records. The Outback is rated at 12 L/100 km (20 US mpg) in the city and 8.6 L/100 km (27 US mpg) on the highway. We ended up averaging averaged 12.4 L/100 km (19 US mpg) during our week, which is fine. The fuel tank holds 70 litres and thankfully the car takes regular fuel.
The combination of the 3.6-litre 6-cylinder and a well thought out CVT makes for a very responsive drivetrain and acceleration is brisk off the line. I found the CVT to be responsive in almost every situation, more so than the average automatic. I also found less mechanical noises and whining than I expected, and overall, there is nothing to complain about with this transmission. It is very well suited to the car.
If you care to manually shift "gears" via the steering wheel mounted paddles, you'll find a very convincing set of fake gear ratios, and the CVT is quicker than virtually any automatic when it comes to popping up or down into a new "gear".
The Outback feels expensive when you're driving – the car's ride is very well sorted out and most of the time it felt downright luxurious. Of course the vehicle is tall and it feels that way when you swing it into the curves. It leans into corners quite noticeably but retains good handling characteristics and confidence inspiring traction. Speaking of traction, the all-wheel drive is one of the most noticeable – even in the dry. In this case, that's a good thing. Somehow Subarus feel different in how they distribute the power, and every situation seems like it is 100% under control, including some very impressive grip on rain-soaked streets.
If you're headed onto the trails, the Outback's X-Mode will help you navigate things with the help of electronics, and there's even a hill descent mode. Road noise and engine noise are not really a big issue, but we really noticed the wind noise becoming intrusive at higher speeds. Too bad, because otherwise it's an excellent highway car.
Yes, it's still a tall wagon that sports SUV-beating ground clearance. The overall shape hasn't changed much, but there are plenty of refinements throughout. One of the first things I noticed is that Subaru took the plastic trim on the sides down a notch – you'll find less nods to Tupperware than ever before. The new grille looks great, and it's flanked by spiffy Xenon HID projector lights. Subaru must have paid close attention to the lights this time around, because in my opinion, even the tail lights look great.
This trim has beefy and handsome 18-inch rims which look as good in an urban setting as they do on a dirt trail.
Owing in part, I'm sure, to Subaru's granola-ey-Vancouver/Seattle-ish-outdoorsy demographic, the Outback sports a massive built-in roof rack system. It's totally integrated and appears to be very sturdy and is likely perfect for a variety of rack systems and attachments, allowing for the transport of bikes, kayaks, roof boxes, etc. I did not get to try it out though.
The exterior is well done, but the real surprise for this all-new Outback came inside. I sat down into the wagon and was nearly dumbfounded. Pictures don't do it justice. The materials are outstanding, especially for Subaru – there are plenty of soft, textured plastics, a very attractive matte-finish wood trim, perforated door panels and contrasting stitching. As a package, it makes for a beautiful interior and the fit and finish is very impressive. I couldn't help but take this interior as an assault on the near-luxury class. The Outback, in this trim, looks and feels very high end. My previous benchmark for Subaru interiors was the Forester – the new Outback is a measurable step up from there.
The space is airy enough, with good headroom but I missed the massive panoramic sunroof from the Forester – there's a standard-sized one here instead.
I found the power-adjustable and heated leather seats to be impressively comfortable. They were not as supportive as I'd like – but this car is clearly comfort oriented and I'm OK with that. Ahead of you is a great steering wheel that gets a bit busy with a ton of jobs to perform – buttons for media, the driver information screen, cruise control and the phone are found here, as well as the shift paddles. Two typical gauges sit in the bin, split by an excellent driver information screen. It's sharp, clean and very useful.
Another very pleasant surprise was at the top of the centre stack where I found the 7-inch Starlink screen, Subaru's excellent new infotainment system. They have done an outstanding job with the user interface in terms of organization and ease of use, and coupled with a sharp, responsive screen with smartphone-like pinch and swipe functions and a 100% reliable voice recognition engine, I would say this is one of the best systems in the industry right now. It's a fantastic way to manage your media, phone, navigation and vehicle information and is obviously the dawn of a new era for Subaru in this department. The 576 watt 12-speaker harman kardon system sounds pretty rockin' too. As you'd expect, there is a dual-zone automatic climate control.
This trim level gets a decent complement of driver assistance technology in the form of blind-spot monitoring, rear cross traffic alert and a rear view camera. I found a couple of strange omissions (especially at this price level) – no keyless entry and no push-button ignition. Frankly it felt strange to start a car this nice (and this expensive) with a key. Opt for the $1200 Technology package and you'll get these items as well as the EyeSight camera-based goodies like lane departure warning, adaptive cruise and pre-collision braking.
I normally don't nitpick too much, but I have to mention the clock. It's placed in the display strip for the climate control system, and because it's tiny and stuck among a bunch of other glowing numbers, I was never able to quickly find it. It requires a longer glance away from the road, and I always got irritated by that.
In the back are three seats, each with its own headrest. The heated seats are quite comfortable and they also recline, which is unusual for wagons. We found the rear seating roomy with good amounts of head room, leg room and foot room. Unfortunately the big centre tunnel squeezes the middle seating positing for foot space, but it remains usable for adults if necessary.
There's not much going on back there. Some adjustable air vents, two map pockets and a middle seatback that folds down to become an armrest with cupholders. No charging plug, which, in my opinion, is unforgivable at this price.
Subaru always does a good job at providing spaces for your everyday stuff. At the bottom of the centre stack (under an angled lid) sits a nice rubberized bin with two USB inputs and a 12V plug. There is a very useful space under the armrest, with another 12V plug and an organizer tray.
Pop the power lift gate (which is a contender for the slowest one of all time) and you'll be greeted by a spacious trunk. 1005 litres to start with. Drop the rear seats, which split 60/40 and can be folded using remote release latches in the trunk, and the space grows to a gargantuan 2075 litres. That's a lot. Subaru throws in a few thoughtful touches like cool bag hooks on the side, a 12V plug and a removable, retractable soft tonneau cover.
The 2015 Outback is simply stated the right vehicle for most people. Yes the looks are a bit subjective, although they shouldn't be. Yes, it's taller than most people think is necessary, but you'll be happy about that when you're clearing the snow and you're able to drive through a ditch or down a crazy dirt trail. It offers plenty of space, more luxury and tech than you might expect (in the higher trim levels anyway), performance aplenty and a level of refinement not seen in Subarus before.
The 3.6 is a good engine, but I'd really love to see the Forester XT's direct-injected turbocharged 2.0-litre available here. It's a wonderful match for the CVT and provides a delicious amount of oomph at low RPMS. I loved it in the Forester and I think most people wouldn't miss the 3.6 if they'd bring the turbo 4-cylinder over to the Outback.
WAF (Wife Acceptance Factor) was very high. She wasn't a huge fan of the Forester, but the Outback really resonated with her. My girl is a wagon fan, and the overall styling appealed to her, as did the fancy-shmancy interior. She loved driving it.
I'm a Subaru fan – that's all there's to it. And the Outback further cements that into place. I wouldn't hesitate to recommend the Outback to most people in North America – it's probably the right car for you, and you might not have realized it. And no, you don't have to drop 40 grand on it. They start at significantly lower prices, and you'll still get a bang-up car, regardless of which trim level you choose.
Great job on the new Outback, Subaru. Keep it up – you're knocking them out of the park in the last few years.
Disclosure: Vehicle was provided by Subaru Canada.


The District of Columbia Housing Authority, city officials, and community members cut the ribbon on the final building in the Highland Dwellings redevelopment.
The $70 million comprehensive gut rehabilitation project began in 2014 and completely refurbished the more than 200-unit complex in multiple phases. The final phase is the 24-unit senior building at 400 Atlantic Avenue, S.E.
"It was important to me that the last thing I did as Executive Director of the D.C. Housing Authority was to not only be in Ward 8, but to be here at Highland," said Adrianne Todman at the ceremony on May 19.
The project started with a simple $7 million stimulus grant for painting, but soon DCHA's Office of Capital Programs realized it would be better to completely redo the complex.
"Now Highland Dwellings is bringing a sense of vitality to this corridor," said Todman, who noted that the senior building is helping many former Highland Dwellings residents stay in the neighborhood.
Ward 8 Council member Trayon White cheered for his neighbors coming back. White was raised just three blocks away from the complex.
In addition to DCHA's funding, bond proceeds, and tax credit equity funding, the D.C. Housing Finance Agency invested $35.5 million into the project to make it possible.
He said, "The housing authority is one of the most prolific builders in this city" creating "safe, quality housing" for all D.C. residents.
The 24-unit senior building includes 10 units for the disabled and 3,000 square feet of commercial space or program space.


Oregon Tech's online degree program allows students to earn a Bachelor of Science in Operations Management (OM). The program prepares individuals for careers in many fields including production planning, inventory control, industrial engineering, production supervision and quality control.
Graduates typically work in manufacturing, manufacturing engineering, industrial engineering, production control, finance, and quality assurance departments.
Our program offers continuing education in your profession, advancement or new options in your career, and the bachelor's degree required for entry into master's degree programs. Many of our students go on to advanced degrees in a variety of business and operations management programs.
There are several options in the online OM degree. For the recent community college graduate with an Associate degree, Oregon Tech has a degree completion plan built upon the credits you have completed at the community college. Once those credits have been evaluated, an advisor will work closely with you to develop an individualized plan to complete your program requirements. The OM degree has a significant number of elective credits allowing you and your advisor to design a program that meets your personal and professional goals.
Another option is available for those who have earned few or no college or university transfer credits. Students can begin the program regardless of the number of credits they have earned.


Whether an employee is relocating for a short-term or a long-term assignment or travelling on a business trip, temporary housing is frequently required. In the case of long-term assignments, serviced apartments may typically be used to accommodate the relocating employee and the accompanying family until a permanent home has been identified.
IKAN's aim is to provide the highest standard of cost-effective and flexible temporary accommodations. The range of temporary housing options including serviced apartments and short-term rentals will suit any short-term living requirement.
Our relocation professionals will advise on the most suitable option for your relocating employees based on their individual preferences and requirements.
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text:
Diabetes Drug Might Also Help Treat Heart Disease
Diabetes Drug That Also Treats Obesity Could Make Billions
Drug that lowers blood sugar to combat type 2 diabetes 'also helps fight obesity and heart disease'
Diabetes Drug Can Now Be Used to Treat Obesity
Is it possible to catch diabetes? It sounds absurd, but that's what a reputable new study suggests. And it may be that other 'lifestyle' diseases such as joint pain and even obesity are contagious, too
How To Use Frozen Lemons To Treat Obesity, Diabetes, Tumors
Obesity Action Coalition Dear Doctor Can Bariatric Surgery Treat Type 2 Diabetes?
Broccoli Compound Lowers Risk of Obesity and Helps Treat Diabetes
Powerful new cancer drugs are saving lives, but can also ignite diabetes or other autoimmune conditions
Semaglutide is a compound that's already being developed as a treatment for diabetes, by Danish pharmaceutical company Novo Nordisk. According to a new study conducted by scientists from the University of Leeds, however, it may serve another valuable purpose – it could greatly aid the obese is losing weight.
The chemical structure of semaglutide is very similar to that of GLP-1, a naturally-occurring hormone that is thought to act on the appetite control centre in the hypothalamus region of the brain, reducing feelings of hunger. With that in mind, a team led by Prof. John Blundell was recruited by Novo Nordisk, to see if it could also be used as a weight-loss medication.
The study incorporated 28 test subjects, all of whom were clinically obese, with a body mass index range of 30 to 45 kg/m2. For 12 weeks, half of them received a weekly dose of semaglutide, while the other half were given a placebo – neither group knew which they were getting.
At the end of that period, they were invited to a testing center to have their body weight and body composition recorded, where they were given a lunch and evening meal. They were told to eat as much as they wanted in order to feel "pleasantly full." The amount that each person consumed was noted, along with their food-type preferences.
The whole 12-week process was then repeated, with the placebo group now receiving semaglutide and vice-versa.
It was found that when given the meals, the people receiving semaglutide ate considerably less than their placebo-taking counterparts, and showed less of a preference for high-fat foods. M Continue reading
Risk of Diabetic Ketoacidosis after Initiation of an SGLT2 Inhibitor
Inhibitors of sodium–glucose cotransporter 2 (SGLT2) decrease plasma glucose by blocking the reabsorption of glucose at the proximal tubule.1,2 Case reports have suggested that SGLT2 inhibitors may be associated with an increased risk of diabetic ketoacidosis, which led to a warning from the Food and Drug Administration (FDA) in May 2015.3,4 The objective of our study was to assess the risk of diabetic ketoacidosis after the initiation of an SGLT2 inhibitor.
Using a large claims database of commercially insured patients in the United States (Truven MarketScan), we identified a cohort of adult patients (≥18 years of age) who had newly started treatment with either an SGLT2 inhibitor or a dipeptidyl peptidase-4 (DPP4) inhibitor between April 1, 2013, and December 31, 2014 (before the FDA warning). DPP4 inhibitors were chosen as the comparator medication because they are similarly used as a second-line treatment for diabetes but have no known association with diabetic ketoacidosis. We excluded patients with human immunodeficiency virus infection, end-stage renal disease, cancer, type 1 diabetes, or past diabetic ketoacidosis. Our primary outcome was hospitalization for diabetic ketoacidosis (using the primary position code of the International Classification of Diseases, Ninth Revision) within 180 days after the initiation of an SGLT2 inhibitor or a DPP4 inhibitor. We censored data for patients at the time that they discontinued the initial medication, had the outcome, lost insurance coverage, or died.
We used 1:1 propensity-score matching to balance 46 char Continue reading
New diabetes research takes a page from the past with a drug from the 1950s | Miami Herald
Prior to Daniel Dyner having open-heart surgery four years ago, he appeared to be in great health.
He had just moved to Key Biscayne from Venezuela, where he spent his time sailing around the world on solo trips to places like Trinidad, the Mediterranean and the coast of Africa. He swam nearly a mile every day and kept a strict diet.
The 69-year-old Dyner was on the first lap of his daily swim in May 2013 when he "suddenly felt funny."
He immediately went to see Dr. Gervasio Lamas, his cardiologist at Mount Sinai Medical Center in Miami Beach.
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"I remember this so distinctly," said Dyner, now 73. "The guy said 'stop' and he ran over with two doctors. They said I had 24 hours to live."
Jose A. Iglesias [email protected]
The next morning, Dyner underwent open-heart surgery. After that, his sugar levels went "completely crazy."
Now, Dyner is part of Lamas' clinical trial at Mount Sinai, where Type 2 diabetics with a history of cardiac arrest might find a solution to their complications. The key? A drug developed in the 1950s.
To treat diabetes in new ways, South Florida physicians and researchers like Lamas and Dr. Camillo Ricordi, director of the Diabetes Research Institute at the University of Miami's Miller School of Medicine, are looking to the past for answers.
Both are testing alternative techniques in hopes of bringing unconventional diabetes treatments into the mainstream.
In Type 1 diabetes, which affects about 5 percen Continue reading
New Diabetes treatment available in Palm Beach Gardens
PALM BEACH GARDENS, Fla. —
A new diabetes treatment is being offered at the Nicklaus Children's Palm Beach Gardens Outpatient Center.
"With the new pump there's a lot of consistency and peace of mind and it just helps me live normally," said Colton Smith, a 16-year-old high school football player who has Type 1 diabetes and started treatment a few months ago.
The Medtronic MiniMed 670G system works by automatically measuring blood sugar, predicting when a rise or fall is going to occur, and continuously delivering precise doses of insulin. Eight patients at the center in Palm Beach Gardens are currently using it but medical staff said they'd like to add more.
"When our kids were growing up we had to go to Orlando or Miami and now they can do things here," said legendary golfer Jack Nicklaus. He and his wife Barbara said they are just happy to have the means to be able to help. Continue reading
Diabetes educator role boundaries in Australia: a documentary analysis
Diabetes educators provide self-management education for people living with diabetes to promote optimal health and wellbeing. Their national association is the Australian Diabetes Educators Association (ADEA), established in 1981. In Australia the diabetes educator workforce is a diverse, interdisciplinary entity, with nurses, podiatrists, dietitians and several other health professional groups recognised by ADEA as providers of diabetes education. Historically nurses have filled the diabetes educator role and anecdotally, nurses are perceived to have wider scope of practice when undertaking the diabetes educator role than the other professions eligible to practise diabetes education. The nature of the interprofessional role boundaries and differing scopes of practice of diabetes educators of various primary disciplines are poorly understood. Informed by a documentary analysis, this historical review explores the interprofessional evolution of the diabetes educator workforce in Australia and describes the major drivers shaping the role boundaries of diabetes educators from 1981 until 2017.
This documentary analysis was undertaken in the form of a literature review. STARLITE framework guided the searches for grey and peer reviewed literature. A timeline featuring the key events and changes in the diabetes educator workforce was developed. The timeline was analysed and emerging themes were identified as the major drivers of change within this faction of the health workforce.
This historical review illustrates that there have been drivers at the macro, meso Continue reading
Sugars found in tequila may protect against obesity, diabetes
Tequila shots may do more than lighten the mood at a party; the drink may be beneficial for your health as well. According to researchers from Mexico, natural sugars derived from the agave plant, called agavins, greatly protected a group of mice against diet-induced obesity and type 2 diabetes, MedPage Today reported. In a new study presented at the American Chemical Society (ACS) annual meeting i ...
Why High-Fat vs. Low-Fat Dairy May Be Better Suited for Those with Diabetes, Obesity, and Cardiovascular Disease
Diabetes, Cardiovascular Disease, Obesity and the High-Fat, Low-Fat Dairy Debate Penny Brooks is a Registered Dietitian, who at the age of 12 was diagnosed with prediabetes, which she reversed within a year. Based on her personal experience and expertise in nutrition, she discusses the health benefits of the full fat dairy option in the context of obesity, diabetes, and cardiovascular disease. ...
Asthma drug shows promise in treating obesity and diabetes
ANN ARBOR, Mich. -- After 12 weeks of taking an anti-inflammatory asthma drug, obese patients with type 2 diabetes (link is external) showed a clinically significant drop in blood glucose. The drug amlexanox, prescribed in Japan to treat asthma, appeared to free the metabolic system to burn more energy. A subset of patients had improved fatty liver disease and insulin sensitivity, a response seen ...
Type 2 diabetes breakthrough: Scientists create first pill that not only STOPS the condition in its tracks but also helps patients lose weight - and it could be available on the NHS within 3 years
Scientists have created a new pill that can halt type 2 diabetes in its tracks and help patients shed pounds from their waistlines, a major study has revealed. Results from a human trial of 632 patients found semaglutide allowed 71 per cent of them to shed pounds - it is believed this is the first type 2 diabetes pill to instigate weight loss. Researchers hope semaglutide will offer a better way t ...
Gene That Makes People Behave Like Idiots When Drunk Could Also Protect Against Diabetes
A genetic mutation that has been found to cause people to act outrageously when they're drunk also appears to lower the risk of certain metabolic disorders such as diabetes and obesity. Peculiarly, the mutation has so far only been found in Finnish people, and is thought to affect around 100,000 people in the Nordic country. The mutation in question inhibits the production of serotonin 2B recept ...
Why eating late at night will do more than just make you gain weight - it also raises risk of diabetes and heart disease, study reveals
There is a well-known link between eating late and weight gain - now new findings suggest it also increases your risk of diabetes and heart disease. A team of US researchers found eating later raises boosts glucose and insulin levels, which are implicated in diabetes. Late-night meals also raise cholesterol and triglycerides, a type of fat in your blood, both which can increase your risk of heart ...
Pill for diabetes that costs just £1.30 a day also cuts the risk of heart and kidney disease by 14%
A cheap anti-diabetes drug slashes the risk of heart attacks and kidney disease, a major study has found. Experts last night said the study, carried out among 10,000 patients in 30 countries, heralds a 'new era' in the treatment of type two diabetes. Canagliflozin, a pill taken once a day before breakfast, is designed to lower blood sugar levels and keep weight down. But the new study, present ...
Blood Pressure Drug Verapamil May Reverse Type 1 Diabetes; Human Trials To Begin Next Year
It's really expensive for pharmaceutical companies to develop a single new drug. According to Forbes, it can cost anywhere from $1.3 billion to $5 billion. Because of this, it makes drug companies very happy when they discover one of their drugs can be used for other health conditions — after all, more people treated means more money in executive's pockets. Well, a case like this was just di ...
Diabetes drug may help in leukaemia
A drug used to treat diabetes could help in the fight against blood cancer, early research in the journal Nature suggests. An international team of scientists gave the drug to patients with chronic myeloid leukaemia, alongside standard treatment. Those who received the combination therapy were more likely to be free of the disease for longer. Chronic myeloid leukaemia (CML) is a rare blood cancer. ...
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redpajama_set_name: RedPajamaCommonCrawl


Authored by akshjain.jain74 on Feb 11 2019, 2:10 PM.
akshjain.jain74 retitled this revision from config.txt: Add better documentation for ui.tweakdefault (issue6000) to config.txt: Add better documentation for ui.tweakdefault (issue6000) *** config.txt: Add better documentation for ui.tweakdefault (issue6000).
akshjain.jain74 retitled this revision from config.txt: Add better documentation for ui.tweakdefault (issue6000) *** config.txt: Add better documentation for ui.tweakdefault (issue6000) to config.txt: Add better documentation for ui.tweakdefault (issue6000).
akshjain.jain74 retitled this revision from config.txt: Add better documentation for ui.tweakdefault (issue6000) to tweakdefault: Add better documentation for ui.tweakdefault (issue6000).
Hi, thanks for the patch. This is adding just un required churn to help text.
As commented on the issue, I don't think we need anything more.


text:
Justia Patents Wrinkle RemoverUS Patent for Flux, solder paste, and method for forming solder bump Patent (Patent # 10,836,000)
Flux, solder paste, and method for forming solder bump
Sep 20, 2018 - TAMURA CORPORATION
A flux includes a rosin resin, an activator, a thixotropic agent, and a solvent. The solvent includes 30% by mass or more and 60% by mass or less monovalent alcohol with respect to a total mass amount of the flux. The monovalent alcohol has 18 or more and 24 or less of carbon atoms in one molecule.
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The present applications claims priority under 35 U.S.C. § 119 to Japanese Patent Application No. 2017-181824, filed Sep. 21, 2017 and Japanese Patent Application No. 2018-169221, filed Sep. 10, 2018. The contents of these applications are incorporated herein by reference in their entirety.
BACKGROUND Field of the Invention
The present invention relates to a flux, a solder paste, and a method for forming a solder bump.
Discussion of the Background
When electric components are joined to an electric circuit formed on a substrate such as a printed circuit board or a silicon wafer, a solder alloy is used as the joining material.
Examples of the joining using the solder alloy include a method of printing a solder paste composed of a solder alloy powder and a flux on a substrate, and a method of joining using solder bumps of a solder alloy formed on a substrate. The solder paste may be used for forming the solder bumps.
Common fluxes used in solder pastes are mainly comprised of a resin such as a rosin, and made by melting an activator and a thixotropic agent in a solvent. However, a solder paste using a prior art flux can cause voids in solder joints formed during reflowing after printing the solder paste on electrodes. These voids decrease joining properties and heat dissipation between the joint and the part to be joined such as a substrate and electronic components, and can decrease reliability of electronic devices and semiconductors.
In recent years, as a method for forming solder bumps using a solder paste, a dry film process is used. According to the process, firstly, a dry film is attached to a substrate having a certain electronic circuit or a certain electronic circuit and an insulating layer formed thereon, and the object is subjected to exposure and development according to a certain pattern. As a result of this, the portion of the resist component where solder bumps are to be formed (on the electrodes) on the dry film is removed, a dry film layer having a certain pattern is formed on the substrate, and a region (opening) surrounded by the dry film layer is formed. Subsequently, printing is carried out in such a manner that the solder paste is charged into the opening, and the object is reflowed as it is, thereby forming solder bumps. Furthermore, the dry film layer and the flux residue formed near the solder bumps are removed.
When solder bumps are formed using the dry film process, in comparison with other bump formation methods, a phenomenon of easy void occurrence in solder bumps and a phenomenon of missing bumps which is the loss of solder bumps from the substrate during removal of the flux residue, tend to occur.
The voids in solder bumps are likely caused by the flux component which has not been discharged after being taken into the molten solder alloy during reflowing. The cause of the missing bumps is also considered as follows: the molten solder alloy does not thoroughly spread to the bottom of the opening because of the decrease in flowability of the flux during reflowing, and the flux remains on the bottom to become a residue. These are caused by the increase in the viscosity of the flux and the decrease in flowability of the flux because of the vaporization of the solvent contained in the flux during reflowing.
When solder bumps are formed by the dry film method, the film thickness of the dry film layer forming the opening tends to be greater than the masks used in other methods. Therefore, in this case, the height from the surface of the dry film layer to the bottom of the opening (depth of the opening) increases, which hinders spread of the molten solder alloy to the bottom of the opening, and the flux easily accumulates on the bottom, which likely promotes the occurrence of missing bumps.
As a method for suppressing the occurrence of missing bumps, for example, disclosed is a solder paste which has a viscosity allowing feeding into an opening under a reduced pressure and charging into the opening at an atmospheric pressure, and includes a solvent for adjusting the viscosity and thixotropic ratio and having a boiling point of 240° C. or higher (see International Publication WO 2012/173059 A).
According to a first aspect of the present invention, a flux includes a rosin resin, an activator, a thixotropic agent, and a solvent. The solvent includes 30% by mass or more and 60% by mass or less monovalent alcohol with respect to a total mass amount of the flux. The monovalent alcohol has 18 or more and 24 or less of carbon atoms in one molecule.
According to a second aspect of the present invention, a solder paste includes a solder alloy powder and a flux. The flux includes, a rosin resin, an activator, a thixotropic agent, and a solvent. The solvent includes 30% by mass or more and 60% by mass or less monovalent alcohol with respect to a total mass amount of the flux. The monovalent alcohol has 18 or more and 24 or less of carbon atoms in one molecule.
According to a third aspect of the present invention, a method for forming a solder bump, includes providing an electrode and a first insulating layer on a substrate, providing a second insulating layer on the first insulating layer such that an opening is provided on the electrode, filling the opening with a solder paste including a solder alloy powder and a flux, the flux including a rosin resin, an activator, a thixotropic agent, and a solvent, the solvent including 30% by mass or more and 60% by mass or less monovalent alcohol with respect to a total mass amount of the flux, the monovalent alcohol having 18 or more and 24 or less of carbon atoms in one molecule, heating the substrate to form a flux residue after the opening is filled with the solder paste, and removing the flux residue and the second insulating layer to form the solder bump.
A more complete appreciation of the invention and many of the attendant advantages thereof will be readily obtained as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings.
FIG. 1 illustrates a temperature profile in a void test and a missing bump test on solder pastes according to Examples and Comparative Examples, and in a viscosity measurement after heating (reflowing) of fluxes according to the embodiment, Examples, and Comparative Examples; and
FIG. 2 is a schematic view of a substrate for forming solder bumps in the void test and the missing bump test of the solder paste according to Examples and Comparative Examples.
DESCRIPTION OF THE EMBODIMENTS
The embodiment(s) will now be described with reference to the accompanying drawings, wherein like reference numerals designate corresponding or identical elements throughout the various drawings.
One embodiment of the flux and solder paste of the present invention will be described below in detail.
The present invention will not be limited to the embodiment.
1. Flux
The flux according to the present embodiment includes a rosin resin, an activator, a thixotropic agent, and a solvent.
Examples of the rosin resin include rosin such as tall oil rosin, gum rosin, and wood rosin; and rosin derivatives such as hydrogenated rosin, polymerized rosin, unhomogenized rosin, acrylic modified rosin, maleic modified rosin, and formylated rosin.
Among these rosin resins, those having a softening point of 100° C. or lower are preferably used. By using rosin resins having a low softening point, flowability of the flux can be improved during heating (reflowing), which allows a solder alloy powder to easily precipitate and thereby suppressing effect of the occurrence of missing bumps is improved.
The loading of the rosin resin is preferably 25% by mass or more and 50% by mass or less, and more preferably 30% by mass or more and 40% by mass or less with reference to the total amount of the flux.
Examples of the activator include amine salts such as hydrohalide salts of organic amines (inorganic acid salts and organic acid salts), organic acids, organic acid salts, organic amine salts, and brominated halogen compounds. Specific examples include diethylamine salts, acid salts, succinic acid, adipic acid, sebacic acid, glutaric acid, diphenylguanidine hydrobromide, cyclohexyl amine hydrobromide, brominated triallyl isocyanurate, tris(2,3-dibromopropyl)isocyanurate, and poly-8,13-dimethyl-8,12-eicosadienedioic acid anhydride. Among them, poly-8,13-dimethyl-8,12-eicosadienedioic acid anhydride is preferably used as the activator. Poly-8,13-dimethyl-8,12-eicosadienedioic acid anhydride is in a liquid state at normal temperature and with excellent stability under high temperature because of long chain compound, and thereby suppressing effect of void occurrence and missing bump is improved.
They may be used alone or in combination of two or more.
The loading of the activator depends on the other component and the lead-free solder alloy to be used, but is commonly 20% by mass or less with reference to the total amount of the flux.
Examples of the thixotropic agent include hydrogenated castor oil, bisamide thixotropic agents (saturated fatty acid bisamide, unsaturated fatty acid bisamides, and aromatic bisamides), and dimethyldibenzylidene sorbitol. Among them, hydrogenated castor oil is particularly preferably used as the thixotropic agent. In comparison with other thixotropic agents, hydrogenated castor oil has low softening point, which allows flowability of the flux to be improved during heating (reflowing). Thus, a solder alloy powder can be easily precipitated and thereby suppressing effect of the occurrence of missing bumps is improved.
The loading of the thixotropic agent is preferably 3% by mass or more and 10% by mass or less, and more preferably 5% by mass or more and 8% by mass or less with reference to the total amount of the flux.
Examples of the solvent include alcohol-based, ethanol-based, acetone-based, toluene-based, xylene-based, ethyl acetate-based, ethyl cellosolve-based, butyl cellosolve-based, glycol ether-based, and ester-based ones. They may be used alone or in combination of two or more.
The flux according to the present embodiment preferably include, as the solvent, a monovalent alcohol having 18 or more and 24 or less carbon atoms in one molecule.
Such monovalent alcohol is resistant to volatilization even when the heating (reflowing) temperature is high. This reduces the volatilization amount of the solvent during heating (reflowing), and prevents the decrease in flowability of the flux. This hinders inclusion of the flux component in the solder alloy molten by heating (reflowing), and suppresses the occurrence of voids.
Also in the formation of solder bumps, the solder alloy molten on the bottom of the opening during heating (reflowing) easily flows, whereby the occurrence of missing bumps is suppressed. These effects are also achieved in the formation of solder bumps by the dry film process wherein the opening has a greater depth, and the occurrence of missing bumps can be suppressed even in in this process.
Another method for suppressing the decrease in flowability of the flux in heating (reflowing) is the use of an ester solvent having a high boiling point (the volatilization amount at high temperatures is small).
However, such ester solvents are often poorly soluble in other flux components such as an activator and a thixotropic agent. Therefore, these ester solvents have been commonly unuseful as a flux without being combined with other solvent having high solubility and a low boiling point.
However, the flux according to the present embodiment includes a monovalent alcohol having 18 or more and 24 or less carbon atoms in one molecule as the solvent, so that it does not necessarily requires the combination with other solvent having a low boiling point, and suppresses the decrease in flowability of the flux during heating (reflowing) even when used alone. However, combination of the monovalent alcohol and other solvent is not excluded, and they may be combined as necessary.
The carbon atoms contained in one molecule of the monovalent alcohol is preferably 18 or more and 20 or less.
The monovalent alcohol is preferably a branched alcohol or an unsaturated alcohol.
Examples of the monovalent alcohol include oleyl alcohol, isostearyl alcohol, isoeicosanol, 2-octyldodecanol, and 2-decyltetradecanol. Among them, oleyl alcohol, isostearyl alcohol, isoeicosanol, and especially 2-octyldodecanol, are preferably used. They may be used alone or in combination of two or more.
The loading of the solvent is preferably 30% by mass or more and 60% by mass or less, and even more preferably 40% by mass or more and 50% by mass or less with reference to the total amount of the flux.
The loading of the monovalent alcohol is preferably 30% by mass or more and 60% by mass or less, more preferably 35% by mass or more and 55% by mass or less, and even more preferably 40% by mass or more and 50% by mass or less with reference to the total amount of the flux. By keeping the loading of the monovalent alcohol within the aforementioned range, suppressing effect of void occurrence of solder bump is improved.
The flux according to the present embodiment may include an antioxidant for the purpose of preventing oxidation of the solder alloy powder.
Examples of the antioxidant include hindered phenol antioxidants, phenol antioxidants, bisphenol antioxidants, and polymer antioxidants. Among them, hindered phenol antioxidants are particularly preferably used.
The antioxidant will not be limited to them, and the loading is not particularly limited. The loading is commonly about 0.5% by mass to 5% by mass with reference to the total amount of the flux.
The flux according to the present embodiment may further include an additive such as a halogen, a delustering agent, or an anti-foaming agent. The loading of the additive is preferably 10% by mass or less, and even more preferably 5% by mass or less with reference to the total amount of the flux.
The flux according to the present embodiment preferably has a viscosity of 30 Pa·s or less after heating under the reflowing condition in which the temperature is risen from normal temperature to a peak temperature of 260° C. at a temperature rising rate of 2° C./second, and the temperature is decreased at a temperature decreasing rate of 2° C./second after reaching the peak temperature as shown in the temperature profile given in FIG. 1. Also, the viscosity of 25 Pa·s or less is preferable.
In the measurement of the viscosity, firstly, 4 g of the flux according to the present embodiment is placed in an aluminum petri dish, and the petri dish is placed on a gauze, and reflowed using a reflowing apparatus. The reflowing conditions are in accordance with the temperature profile (above reflowing condition) given in FIG. 1.
The flux after reflowing is returned to normal temperature, and its viscosity is measured using an E type viscometer. The viscosity was measured at a rotation speed of 10 rpm and a measurement temperature of 25° C.
2. Solder Paste
The solder paste according to the present embodiment can be prepared by mixing the flux according to the present embodiment and a solder alloy powder by a known method.
Examples of the solder alloy powder include combinations of Sn, Ag, Cu, Bi, Zn, In, Ga, Sb, Au, Pd, Ge, Ni, Cr, Al, P, In, and Pb. The alloy composition of the solder alloy powder is not particularly limited, as long as it will not impair the effect of the solder paste according to the present embodiment.
Typical examples of the solder alloy powder include lead free solder alloy powders such as Sn—Ag solder alloy, Sn—Ag—Cu solder alloy, Sn—Ag—Cu—In solder alloy, and Sn—Cu solder alloy, and lead-containing solder alloy powder may be used.
The loading of the solder alloy powder is preferably from 63% by mass to 93% by mass, more preferably from 84% by mass to 92% by mass, and particularly preferably from 86% by mass to 90% by mass with reference to the total amount of the solder paste.
3. Solder Joint
The solder joint formed using the solder paste according to the present embodiment is formed by, for example, the following method.
More specifically, the solder paste is printed on the substrate in the predetermined position, and an electronic component is mounted on the substrate in the predetermined position, and the object is reflowed, thereby forming the solder joint. The solder joint thus formed causes few void and has high reliability, and thus is suitably used for semiconductors and electronic devices.
4. Solder Bumps
The solder bumps formed using the solder paste according to the present embodiment are formed by, for example, the following method.
Firstly, electrodes and an insulating layer having a certain pattern are formed on a substrate. The insulating layer may be made by any method as long as it forms a layer including an insulating component and having a certain film thickness, such as a liquid solder resist or a dry film.
Subsequently, a metal mask corresponding to the pattern (the above of the electrodes is open) is placed on the substrate so as to be in contact with the insulating layer, and the solder paste is printed using a squeegee or the like so as to be charged into the open region on the electrodes. Thereafter, the substrate is placed in a reflowing apparatus, and reflowed according to a certain temperature profile. After reflowing, the flux component (flux residue) is removed from the substrate, thereby forming solder bumps.
The solder paste according to the present embodiment may form solder bumps by a dry film process. The method for forming solder bumps by the dry film process is, for example, as follows.
Firstly, an electrode part and an insulating layer having a certain pattern are formed on a substrate. The method for making the insulating layer is not particularly limited as long as it forms a layer including an insulating component and having a certain film thickness, such as a liquid solder resist or a dry film.
Subsequently, a dry film layer is formed on the insulating layer. The dry film layer is formed by attaching a dry film to the substrate in a certain range so as to be in contact with the insulating layer, and subjecting the object to exposure and development according to a certain pattern. More specifically, the exposure and development operations remove the resist component of the dry film in the area where solder bumps are formed (on the electrodes), and a dry film layer having a certain pattern is formed on the substrate. As a result of this, a region surrounded by the dry film layer (opening) is formed.
Then, printing is carried out in such a manner that the solder paste is charged into the opening using a squeegee or the like. Thereafter, the substrate is place in a reflowing apparatus, and reflowed according to a certain temperature profile. After the reflowing, the flux component (flux residue) and the dry film layer remaining on the substrate are removed, thereby forming solder bumps.
The solder bumps thus formed suppresses the decrease in flowability of the flux during reflowing of the solder paste, which suppresses the occurrence of voids in the solder bumps, and also suppresses the occurrence of missing bumps during solder bump formation.
The present embodiment will be described below in detail with reference to Examples and Comparative Examples. The present invention will not be limited to these examples.
Making of Flux
The components were mixed according to the composition and recipe given in Table 1, thus making the fluxes according to Examples 1 to 8 and Comparative Examples 1 to 7. In Table 1, the unit of the values concerning the compositions is % by mass, unless otherwise specified.
Subsequently, 12% by mass of the flux according to Examples 1 to 8 and Comparative Examples 1 to 7 and 88% by mass of the Sn-3Ag-0.5Cu solder alloy powder (powder particle size from 2 μm to 8 μm: IPC standard Type 8) are mixed, thereby obtaining the solder paste according to Examples 1 to 8 and Comparative Examples 1 to 7.
Comparative Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 Example 7 Example 8 Example 1 Rosin resin FORAL AX *1 16 16 16 16 16 16 16 13.5 16 HARITACK FG-90 *2 16 16 16 16 16 16 16 13.5 16 Activator Taic-6B *3 1 1 1 1 1 1 1 1 1 Glutaric acid 1 1 1 1 1 1 1 1 1 IPU-22AH *4 9 4 9 9 9 9 14 4 9 Thixotropic Hydrogenated 7 7 7 7 7 7 7 7 7 agent castor oil Solvent NJCOL 240A *5 50 NJCOL 200A *6 40 50 FINEOXOCOL 50 2000 *7 Isostearyl Alcohol 50 30 60 EX *8 Oleyl alcohol 50 (carbon atoms 18: unsaturated) NJCOL 160BR *9 Isotridecanol (carbon atoms 13: branched) 2-ethylhexyl 15 15 diglycol Octanediol DOS *10 50
Comparative Comparative Comparative Comparative Comparative Comparative Example 2 Example 3 Example 4 Example 5 Example 6 Example 7 Rosin resin FORAL AX *1 16 16 16 16 11 16 HARITACK FG-90 *2 16 16 16 16 11 16 Activator Taic-6B *3 1 1 1 1 1 1 Glutaric acid 1 1 1 1 1 1 IPU-22AH *4 9 9 9 14 4 9 Thixotropic Hydrogenated 7 7 7 7 7 7 agent castor oil Solvent NJCOL 240A *5 NJCOL 200A *6 FINEOXOCOL 2000 *7 Isostearyl Alcohol 25 65 EX *8 Oleyl alcohol (carbon atoms 18: unsaturated) NJCOL 160BR *9 50 Isotridecanol 50 (carbon atoms 13: branched) 2-ethylhexyl 50 20 diglycol Octanediol 50 DOS *10 *1: fully hydrogenated modified rosin (softening point 80° C.) Eastman Chemical Company NYSE *2: formylated rosin (softening point 85 to 95° C.) Harima Chemicals Inc. *3: tris(2,3-dibromopropyl) isocyanurate, Nippon Kasei Chemical Co., Ltd. *4: poly-8,13-dimethyl-8,12-eicosadienedioic acid anhydride, Okamura Oil Mill, Ltd. *5: 2-decyltetradecanol (carbon atoms 24: branched), New Japan Chemical Co., Ltd. *6: 2-octyldodecanol (carbon atoms 20: branched), New Japan Chemical Co., Ltd. *7: isoeicosanol (carbon atoms 20: branched), Nissan Chemical Industries, Ltd. *8: isostearyl alcohol (carbon atoms 18: branched), KOKYU ALCOHOL KOGYO CO., LTD. *9: 2-hexyldecanol (carbon atoms 16: branched), New Japan Chemical Co., Ltd. *10: bis(2-ethylhexyl) sebacate, DAIHACHI CHEMICAL INDUSTRY CO., LTD.
<Weight Reduction Rate>
The solvent components were measured for the weight reduction rate at 220° C.
The weight reduction rate was measured under the following conditions. More specifically, the weight reduction rate after heating 10 mg of the sample to 220° C. at a temperature rising rate of 10° C./min in an N2 (300 mL/min) atmosphere using a thermogravimetry/differential thermal analyzer (product name: STA7200RV, Hitachi, High-Technologies Corporation) was measured. The results are given in Table 2.
TABLE 2 Solvent Weight reduction rate (%)
NJCOL 240A −2 NJCOL 200A −7 FINEOXOCOL 2000 −17 Isostearyl Alcohol EX −15 Oleyl alcohol −11 (carbon atoms 18: unsaturated) NJCOL 160BR −32 Isotridecanol −100 (carbon atoms 13: branched) 2-ethylhexyl diglycol −100 DOS −1 Octanediol −100
<Void Test>
As illustrated in FIG. 2, electrodes 2, an insulating layer 3, a dry film layer 4, and an opening 5 are formed on a substrate 1. The substrate 1 having this structure is made by, for example, the following method.
Firstly, the electrodes 2 and the insulating layer 3 having a certain pattern were formed on the substrate 1 (size: 250 mm×75 mm). The insulating layer 3 may be made by any method as long as it forms a layer including an insulating component and having a certain film thickness, such as a liquid solder resist or a dry film. The diameter of the opening in the surface (top surface) of the insulating layer 3 was 85 μm.
Subsequently, the dry film layer 4 was formed on the insulating layer 3. The dry film layer 4 was formed by attaching a dry film (product name: WB-5040, Du Pont K.K.) to the substrate 1 in a certain range so as to be in contact with the insulating layer 3, and subjecting the object to exposure and development according to a certain pattern. More specifically, the exposure and development removed the portion of the resist component where solder bumps were to be formed (on the electrodes 2) on the dry film, thereby forming the dry film layer 4 having a certain pattern on the substrate 1. The height (thickness) of the dry film layer 4 was 38 μm and the width was 35 μm, the diameter of the opening in the surface (top surface) of the dry film layer 4 was 115 μm, and the pitch width (the distance from A to B in FIG. 2) was 150 μm. As a result of this, a region (opening 5) surrounded by the dry film layer 4 was formed.
Subsequently, using a urethane squeegee, the solder pastes according to Examples 1 to 8 and Comparative Examples 1 to 7 were printed on each of the substrates 1 so as to be charged into the opening 5. The number of printing was ten times in one direction.
Thereafter, the substrates 1 having the solder pastes printed thereon were placed in a reflowing apparatus (product name: TNP25-538EM, TAMURA Corporation), and reflowed according to the temperature profile given in FIG. 1 in a nitrogen atmosphere (oxygen concentration: 100 ppm or less) without preheating, at a peak temperature of 260° C. and a temperature rising rate and a temperature decreasing rate of 2° C./second. After the reflowing, the remaining portion of the flux component on each of the substrate 1 (flux residue) and the dry film layer 4 were removed, thereby forming solder bumps.
Subsequently, a flux (product name: BF-30, TAMURA Corporation) was applied to the solder bumps thus formed, reflowing was carried out under the same reflowing conditions as that for forming the solder bumps, thereby making the test substrates. The dry film layer 4 was removed using a peeling solution (product name: CLEANTHROUGH A-04: Kao Corporation) and by giving vibration for one minute using an ultrasonic cleaning apparatus (product name: ASU-3M, AS ONE Corporation). The number of pad provided on each of the substrate 1 was 7,200.
For the test substrates thus made, about 500 solder bumps were visually observed for voids using an X ray observation apparatus (product name: XD7600 Diamond, Nordson Dage), and measured for the maximum void diameter (%) and the average void diameter (%) occurred in these solder bumps, and the proportion of the solder bumps wherein those having a void diameter rate of 10% or more occurred (void occurrence rate (%)), and evaluated based on the following criteria. The results are given in Table 3.
Maximum void diameter (%)
⊙: Maximum void diameter is 0% or more and 20% or less
◯: Maximum void diameter is more than 20% and 25% or less
Δ: Maximum void diameter is more than 25% and 30% or less
×: maximum void diameter is more than 30%
Average void diameter (%)
◯: Average void diameter is 0% or more and 15% or less
Δ: Average void diameter is more than 15%
Void occurrence rate (%)
⊙⊙: Void occurrence rate is 0% or more 25% or less
⊙: Void occurrence rate is more than 25% and 35% or less
◯: Void occurrence rate is more than 35% and 45% or less
Δ: Void occurrence rate is more than 45% and 50% or less
×: void occurrence rate is more than 50%
<Missing Bump Test>
Each test substrate was made under the same conditions as the void test.
Each study substrate was measured for the number of solder bumps which caused missing bumps, and evaluated based on the following criteria. The results are given in Table 3.
◯: No missing bump (no occurrence)
×: missing bumps occurred
<Viscosity of Flux after Reflowing>
In the measurement of the viscosity, 4 g portions of the fluxes according to Examples 1 to 8 and Comparative Examples 1 to 7 was individually placed in aluminum petri dishes, and the petri dishes were place on a gauze, and reflowed using an reflowing apparatus (product name: TNP25-538EM, TAMURA Corporation). The reflowing conditions followed the temperature profile given in FIG. 1.
Each flux after reflowing was returned to normal temperature, and measured using an E type viscometer (product name: RE150U, Toki Sangyo Co., Ltd.). The viscosity was measured at a rotation speed of 10 rpm and a measurement temperature of 25° C. The viscosity thus measured was evaluated based on the following criteria. The results are given in Table 3.
⊙: 15 Pa·s or less
◯: More than 15 Pa·s and 25 Pa·s or less
Δ: More than 25 Pa·s and 30 Pa·s or less
×: more than 30 Pa·s
Comparative Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 Example 7 Example 8 Example 1 Maximum ◯ ⊙ ⊙ ⊙ ⊙ ◯ ◯ ⊙ Unmeasurable void diameter (%) Average ◯ ◯ ◯ ◯ ◯ ◯ ◯ ◯ void diameter (%) Void Δ ⊙⊙ ⊙⊙ ⊙ ◯ ◯ Δ Δ occurrence rate (%) Number of ◯ ◯ ◯ ◯ ◯ ◯ ◯ ◯ occurrence of missing bumps Flux ⊙ ⊙ ⊙ ◯ ⊙ ⊙ ◯ ⊙ viscosity (Pa · s) after reflow heating
Comparative Comparative Comparative Comparative Comparative Comparative Example 2 Example 3 Example 4 Example 5 Example 6 Example 7 Maximum Δ ◯ Δ ◯ ◯ X void diameter (%) Average ◯ ◯ ◯ ◯ ◯ ⊙ void diameter (%) Void X X X X X X occurrence rate (%) Number of ◯ X X ◯ ◯ X occurrence of missing bumps Flux Δ X X Δ ⊙ X viscosity (Pa · s) after reflow heating
As described above, the solder bumps formed using the solder paste according to Examples achieved good results in the void test (maximum void diameter, average void diameter, and void occurrence rate), indicating that they favorably suppressed the occurrence of missing bumps. Especially, the carbon atoms contained one molecule is 18 or more and 24 or less, and, above all, in Examples 2 to 6 wherein the loading of the monovalent alcohol having carbon atoms of 18 or more and 20 or less in one molecule is 40% by mass or more and 50% by mass or less, it is indicated that the suppressing effect of void occurrence can be improved.
On the other hand, Comparative Example 1 using the ester solvent having a low weight reduction rate at 220° C. was unuseful as a flux, because the other flux components did not thoroughly dissolve. Thus, for Comparative Examples 1, the results of each tests are given as "unmeasurable" since a flux and a solder paste were not able to be prepared.
Comparative Examples 2 to 4 and 7 using a solvent other than the monovalent alcohol having 18 or more and 24 or less carbon atoms in one molecule poorly suppressed the decrease in flowability during reflowing, so that their void occurrence rates in solder bumps were more than 50%, and the results in the other void test and/or missing bump test were inferior to those of the solder pastes according to Examples.
Furthermore, the void occurrence rates were more than 50% in Comparative Example 5 and Comparative Example 6 wherein the loadings of the monovalent alcohol having carbon atoms of 18 or more and 24 or less in one molecule were less than 30% by mass and more than 60% by mass, respectively, with reference to the total amount of the flux.
The present invention has the following structure for achieving the above-mentioned object.
(1) A flux according to the present embodiment includes a rosin resin, an activator, a thixotropic agent, and a solvent, wherein the solvent is a monovalent alcohol having 18 or more and 24 or less of carbon atoms in one molecule, and the loading of the monovalent alcohol is 30% by mass or more and 60% by mass or less with reference to the total amount of the flux.
(2) According to the configuration of the above (1), the carbon atoms contained in one molecule of the monovalent alcohol is 18 or more and 20 or less.
(3) According to the configuration of the above (1) or (2), the monovalent alcohol is a branched alcohol or an unsaturated alcohol.
(4) According to the configuration of any one of the above (1) to (3), wherein the monovalent alcohol is selected from at least one of oleyl alcohol, isostearyl alcohol, isoeicosanol, 2-octyldodecanol, or 2-decyltetradecanol.
(5) According to the configuration of any one of the above (1) to (4), the flux has a viscosity of 30 Pa·s or less after being heated under the reflowing condition in which the temperature is risen from normal temperature to a peak temperature of 260° C. at a temperature rising rate of 2° C./second, and the temperature is decreased at a temperature decreasing rate of 2° C./second after reaching the peak temperature.
(6) A solder paste according to the present embodiment includes the flux according to any one of the above (1) to (5), and a solder alloy powder.
(7) A method for forming a solder bump includes forming an electrode and a first insulating layer on a substrate, forming a second insulating layer on the first layer such that an opening is formed on the electrode, printing such that the opening on the electrode is filled with the solder paste according to the above (6), heating the substrate, on which the opening on the electrode is filled with the solder paste, to form a flux residue, and forming the solder bump by removing the flux residue and the second insulating layer.
The flux and the solder paste using the same of the present embodiment suppress the occurrence of voids in solder joints and solder bumps to be formed, and suppress the occurrence of missing bumps during formation of the solder bumps by suppressing the decrease in flowability of the flux during reflowing of the solder paste.
Obviously, numerous modifications and variations of the present invention are possible in light of the above teachings. It is therefore to be understood that within the scope of the appended claims, the invention may be practiced otherwise than as specifically described herein.
1. A flux comprising:
a rosin resin;
an activator;
a thixotropic agent; and
a solvent including 30% by mass or more and 60% by mass or less monovalent alcohol with respect to a total mass amount of the flux, the monovalent alcohol having 18 or more and 24 or less of carbon atoms in one molecule,
wherein the activator contains a poly-8,13-dimethyl-8,12-eicosadienedioic acid anhydride.
2. The flux according to claim 1, wherein the monovalent alcohol is at least one selected from the group consisting of oleyl alcohol, isostearyl alcohol, isoeicosanol, 2-octyldodecanol, and 2-decyltetradecanol.
3. The flux according to claim 1, wherein a viscosity of the flux is 30 Pa·s or less after the flux is heated under a reflow condition in which the temperature is risen to a peak temperature of 260° C. at a temperature-rising rate of 2° C./second and then the temperature is decreased at a temperature-decreasing rate of 2° C./second.
4. The flux according to claim 1, wherein the monovalent alcohol is a branched alcohol or an unsaturated alcohol.
6. The flux according to claim 1, wherein the carbon atoms contained in the one molecule of the monovalent alcohol is 18 or more and 20 or less.
10. The flux according to claim 9, wherein a viscosity of the flux is 30 Pa·s or less after the flux is heated under a reflow condition in which the temperature is risen to a peak temperature of 260° C. at a temperature-rising rate of 2° C./second and then the temperature is decreased at a temperature-decreasing rate of 2° C./second.
11. A solder paste comprising:
a solder alloy powder; and
a flux comprising: a rosin resin; an activator; a thixotropic agent; and a solvent including 30% by mass or more and 60% by mass or less monovalent alcohol with respect to a total mass amount of the flux, the monovalent alcohol having 18 or more and 24 or less of carbon atoms in one molecule,
12. The solder paste according to claim 11, wherein the monovalent alcohol is at least one selected from the group consisting of oleyl alcohol, isostearyl alcohol, isoeicosanol, 2-octyldodecanol, and 2-decyltetradecanol.
13. The solder paste according to claim 11, wherein the monovalent alcohol is a branched alcohol or an unsaturated alcohol.
15. The solder paste according to claim 11, wherein the carbon atoms contained in the one molecule of the monovalent alcohol is 18 or more and 20 or less.
19. A method for forming a solder bump, comprising:
providing an electrode and a first insulating layer on a substrate;
providing a second insulating layer on the first insulating layer such that an opening is provided on the electrode;
filling the opening with a solder paste including a solder alloy powder and a flux, the flux including a rosin resin, an activator, a thixotropic agent, and a solvent, the solvent including 30% by mass or more and 60% by mass or less monovalent alcohol with respect to a total mass amount of the flux, the monovalent alcohol having 18 or more and 24 or less of carbon atoms in one molecule, wherein the activator contains a poly-8,13-dimethyl-8,12-eicosadienedioic acid anhydride;
heating the substrate to form a flux residue after the opening is filled with the solder paste; and
removing the flux residue and the second insulating layer to form the solder bump.
20. The method according to claim 19, wherein the monovalent alcohol is at least one selected from the group consisting of oleyl alcohol, isostearyl alcohol, isoeicosanol, 2-octyldodecanol, and 2-decyltetradecanol.
20050203575 September 15, 2005 Carson
63-281794 November 1988 JP
08-019891 January 1996 JP
2007-44740 February 2007 JP
WO2012/173059 December 2012 JP
Japanese Office Action for corresponding JP Application No. 2018-169221, dated Oct. 23, 2019 (w/ machine translation).
Japanese Office Action for corresponding JP Application No. 2018-169221, dated May 26, 2020 (w/ machine translation).
Filed: Sep 20, 2018
Date of Patent: Nov 17, 2020
Assignee: TAMURA CORPORATION (Tokyo)
Inventors: Masanori Shibasaki (Iruma), Jun Sugimoto (Iruma), Isao Sakamoto (Iruma)
Primary Examiner: Weiping Zhu
Current U.S. Class: Wrinkle Remover (606/204.35)
International Classification: B23K 35/362 (20060101); H01L 23/00 (20060101); H05K 3/40 (20060101);


text:
Касте́к () — село у складі Жамбильського району Алматинської області Казахстану. Входить до складу Талапського сільського округу.

Село засновано 1859 року як укріплення на кордоні Старшого жузу та киргизьких племен.

Населення — 893 особи (2009; 899 в 1999).

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 На Вікімапії

Населені пункти Жамбильського району (Алматинська область)
Села Алматинської області

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