Generally, the present disclosure relates to isolation of vibration frequency for Semiconductor tool pedestal/pad and raised floor system. The following description is intended to the reader for better understanding the various aspect of present disclosure. It should be understood that these statements are to be read in this light, and not as admissions of prior art.
As semiconductor chips are advancing to smaller nanometer size, the need for isolation of unwanted vibration frequency now takes a central position in fabrication facility design and operation. Low frequency vibration may affect production tools such as lithograph tools and, thereby, lower production yield rate in semiconductor fabrication. Foot traffic over raised floor systems, oscillating pumps, compressors, chillers and AHUs (air handling units) produce low vibration frequencies transmitted through building and clean room floor structure. Contributing to unwanted vibration frequencies, many lines and pipes from pumps, compressors, chiller attach to pedestal under these tools without vibration isolation support mounts. Due to cost and installation time, only critical semiconductor production tools are equipped with vibration controlled and/or active isolation or vibration dampening tool pedestals and pads; most tools relied on it's built in passive vibration isolation systems for vibration control.
Most semiconductor fabrication facilities are routinely remodeled, modified, repurposed multiple times to accommodate new technology due to enormous building cost and prolonged build time. Majority of the semiconductor facilities are remodeled facilities and are designed for previous equipment and vibration requirements, which were built 5, 10, 15 plus years ago.
New semiconductor tools have larger tool footprint, additional increase MEP lines accessed from below the tooling. To accommodate new semiconductor tools, height of raised floor system for the Process level or area has been increased; which many steel and aluminum members also increased in size and diameter. In many instances, areas, which were not designed with “waffle floors”, are raised even higher with elevated floor systems to meet cleanroom downdraft air movement specification. As floor or tool pedestal are raised higher, many hollow steel or aluminum member are used to keep the weight and cost to minimum.
Many semiconductor production support tools are capable of working and supporting new critical dimension production tools, such as lithography tools with or without modifications. New production tools have tighter vibration frequency requirements, which are equipped with designed specific vibration isolated tool pedestal and pads. However, new critical tools are usually operating in conjunction with older support tools with outdated vibration specifications. In many occasions, older tools only rely on its built-in passive vibration isolation systems, for vibration control. Economically, replacing all support tools with matching vibration specification for new key production tools is not feasible.
Improvement for isolation of vibration frequency transmitted through building structure is needed for better production yield rate. It must be economical, schedule driven and with minimal weight for ease of material handling and installation.
One particularly important platform for semiconductor device fabrication is the semiconductor tool pedestal, which provides a platform supporting the production equipment. The requirements for tool pedestal vary depending on the type. The structural requirements are stiffness, mass and vibration isolation mechanism. From the list of many different types of semiconductor production tool pedestals, the lithography tool pedestal has higher demand for requirements. As semiconductor chip node size decreases, list of tool pedestal requiring higher requirements for stiffness, isolation/reduction of vibration are increasing. Such tools are chemical-mechanical planarization (CMP) tool and analysis tool pedestal. In addition, other support tools pedestals are requiring higher level of stiffness and reduction/isolation of vibration requirements, due to fabrication production tool weight increase, and additional number and size of MEP access holes in the tool pedestals. Cost effective means to reduced/isolate vibration and ease of material handling and installation is needed.
Many older semiconductor production support pedestal tools still meet the design and strength requirements for supporting new critical production tools. New production tools have tighter requirements, such as stiffness, vibration isolation and increased electromagnetic interference (EMI) barrier. Rewiring and or retrofitting/additional shielding all EMI emitting electrical lines around EMI sensitive tools to meet new EMI tolerance requirements are not economically feasible.
Disturbance from EMI may degrade the performance of semiconductor processing tools, largely affecting production yield rate. For such reason, most of the modern semiconductor fabrication facilities prohibit the personal use of radio, mobile and other external EMI producing devices inside the FAB. All semiconductor processing tools are surrounded by power and communication data lines below the raised floor and tool pedestal system, producing certain level of EMI. Modern semiconductor production tools have improved insulation from EMI; however, as semiconductor industry is evolving continuously and gradually reducing the chip nodes sizes, improving EMI barrier becomes crucial to many key production tools.
In light of the above, a further need exists for providing a method and system for improved semiconductor processing equipment vibration isolation and reduction.
There is the need for a method and system for eliminating or substantially reducing low frequency vibrations which affect production tools such as lithograph tools by lowering production yield rate in semiconductor fabrication.
There is a further need for a method and system for reducing or preventing the effects of vibration sources, such as foot traffic over raised floor system, pumps, compressors, chillers and AHUs (air handling units) that produce low vibration frequencies transmitted through building and clean room floor structures.
A need exists for a method and system to allow semiconductor production tools having tighter vibration frequency requirements to operate effectively in conjunction with older support tools with outdated vibration specifications.
Furthermore, a need exists for the ability to avoid the enormous expense of replacing all old support tools with new ones having vibration specification matching new key production tools. That is, there is the need to eliminate or substantially reduce the considerations of vibration and noise control in equipment operation from decisions of how and when to replace older equipment.
In addition to the above concerns, there are concerns relating to the need for a method for improved semiconductor processing equipment tool pedestal/pad vibration isolation and reduction. The semiconductor industry is evolving continuously and gradually reducing the chip nodes sizes. The tool pedestal/pad (hereafter denoted as tool pedestal) for modern semiconductor FABs are required have very small tolerance to ambient vibration. Therefore, reduction and isolation of vibration of tool pedestal/pad is the key requirement for safe, reliable and uninterrupted operation of modern semiconductor FABs.
Vibration causes deflection and deflection causes damaging effect to the costly high-precision machine tools, which, in turn, reduces production yield rate. There is a need for a way to suppress the transmission of vibration from the supporting system to machine tools.
A further need exists for and improved the method for improved semiconductor processing equipment tool pedestal/pad vibration isolation and reduction presented that provides a cost-effective, easy-to-fabricate, easy-to-handle, and reliable solutions to vibration suppression and isolation for semiconductor FABs.