Sematech Expands its Role in Contamination Control
The government/industry-funded technology consortium, Sematech, has achieved important goals in semiconductor research that have also targeted contamination control.
By Harold D. Fitch
Redefining its role as the major U.S. consortium devoted to advancing semi conductor technology, Sematech (Austin, TX) is moving into its ninth year with an eye toward strategic partnerships with sister organizations in Europe and Japan. As it tries to build bridges overseas, Sematech is also becoming increasingly independent from the U.S. government, which has provided a large portion of its funding.
In 1987, Sematech was launched to keep the U.S. electronics industry competitive worldwide. The most serious competition was in manufacturing semiconductors and semiconductor fabrication equipment. Semiconductors were deemed the life blood of the commercial and military/aerospace electronics industries. The United States quickly re c ognized that staying on the cutting edge was pivotal to national defense. In 1987, the U.S. percentage of the worldwide semiconductor market had slipped to approximately 38 percent from over 50 percent in 1982. The Japanese share had increased from 28 percent to 44 percent in the same time frame (see figure 1). Clearly something had to be done and Sematech was born. Its mission is to solve the technical challenges required to keep the United States number one in the global semiconductor industry.
To understand Sematech`s goals, it`s important to examine the structure of Sematech, the Semiconductor Research Corp., Sematech Centers of Excellence and SEMI/Sematech. Many of the participants are also leaders in the contamination control field.
Sematech is made up of 11 member companies and the U.S. Department of Defense. The member companies are:
Advanced Micro Devices (Sunnyvale, CA)
American Telephone and Telegraph Co.(New York, NY)
AT&T Global Information Solutions (Dayton, OH)
Digital Equipment Corp. (Maynard, MA)
Hewlett-Packard Corp. (Palo Alto, CA)
Intel Corp. (Santa Clara, CA)
International Business Machines Corp. (Armonk, NY)
Motorola, Inc.(Schaumburg, IL)
National Semiconductor Corp. (Santa Clara, CA)
Rockwell International Corp. (Newport Beach, CA)
Texas Instruments Inc. (Dallas, TX)
To date, Sematech has been funded with $690 million from the U.S. government and a matching amount from its member companies. Each of the members` yearly contributions to Sematech are based on their annual corporate revenues.
Sematech has a physical facility located in Austin, TX, employing more than 800 employees. About 25 percent are assigned to Sematech from its member companies. The balance are direct hires, with about 35 percent from member companies, 20 percent from the semiconductor industry manufacturers, and the balance coming from other industries. The facility in Austin builds development semiconductors and evaluates semiconductor manufacturing equipment and processes. This is where much of the hands-on evaluation of manufacturing enhancements takes place.
To accomplish many of its goals, Sematech also has a cooperative effort with the Semiconductor Research Corporation (SRC), a joint activity of U.S. companies with government participation. SRC strengthens and maintains semiconductor research in U.S. universities and plans and implements basic research carried out by faculty and graduate students in university laboratories across the country. It also manages the Sematech Research Programs at Sematech Centers of Excellence (SCOEs) at various universities (see “Sematech Centers of Excellence”).
SCOEs direct research in specific areas of semiconductor manufacturing such as: contamination/defect assessment and control, lithography, single-wafer processing, metrology, multilevel metalization and interconnection, rapid yield learning, manufacturing processing, and x-ray lithography. The SCOE Program is administered by the Semiconductor Research Corporation.
SEMI/Sematech is an independent organization of over 140 U.S.-owned semiconductor equipment and material suppliers working together with Sematech to provide the communication link between semiconductor manufacturers and their suppliers. Its principal goal is to ensure that its members benefit from the Sematech initiative and meet the needs of the U.S. semiconductor industry.
Key accomplishments of the Sematech organization include:
Semiconductor yield model with defect goals and improvement time lines
Significant tool defect reduction
National roadmap for semiconductor technology
Contamination-free manufacturing (CFM) task force
Mini-environment task force
Optical enhancements of lithography
Chemical-mechanical planarization process development
Acid recycling
Contamination control is key in several of Sematech`s accomplishments. Yield learning is always heavily tied to contamination reduction. After device design testing and process debug and centering, defect reduction is usually the next most important step in climbing the yield curve. Tool defect reduction is also dependent on tool cleanliness targets to pinpoint and eliminate the cause of tool defects. The CFM task force is dedicated to contamination reduction. Finally, acid recycling depends extensively on removal of both dissolved and non-dissolved contamination to be a viable process.
Contamination control would have to be rated as moderately important in the national semiconductor roadmap and the chemical-mechanical planarization process. Therefore, seven of eight major Sematech accomplishments tie directly to contamination control. Lithography system enhancement, however, might not depend directly on contamination control, but its successful use in manufacturing is highly effected by contamination control.
One of the Sematech activities directly related to contamination control is the Contamination-Free Manufacturing Task Force. In 1990, the task force starting looking at the manufacturability of 0.35-micron semiconductors. The Task Force decided to focus heavily on contamination control issues, which they felt were major roadblocks to 0.35-micron manufacturing. In addition, the group generated a gap list of anything they felt needed to be implemented to achieve the 0.35-micron manufacturing ground rules. After 1-1/2 years, the final results provided guidelines for: clean equipment build; manufacturing support items; measurement and cleanliness; and contamination control management. In addition, the gap list targeted better measurement techniques, improved measurement equipment, cleaner chemicals, better filters, improved construction materials and many other items to hit the 0.35-micron goal.
CFM Task Force Chairwoman Carol Davis, who was on a two-year assignment to Sematech from IBM, says the effort was considered successful by the participants because “Task force members freely contributed their experience, technical information, as well as current problems and future concerns, and leading experts in the key areas were provided by member companies. Also, task force members worked as effective teams to generate guidelines that would further the science of contamination control and the CFM task force results were everyone`s primary concern, therefore, we all worked toward a common goal.”
“Working toward a common goal” was no coincidence, says Davis. In fact, its work was modeled after the successes of Dr. Tadahiro Ohmi and the Japanese members of the task force on similar projects. One of the important aspects of this approach is that suppliers can now concentrate on the needs of an industry as a whole and not get conflicting inputs from 15 or 20 separate customers. The task force proved that setting and achieving common goals for successfully enhancing technology was possible. Almost all of the gap list items, identified by the task force, have been accomplished within two years.
Another Sematech activity tied directly to contamination control is the mini-environment study. This activity is similar to the CFM task force with one major exception–its scope is worldwide. The European counterpart to Sematech, JESSI, is a partner in the project. Because mini-environments were fairly new to the marketplace when the mini-environment study began, the major effort was concentrated on measurements, data gathering, and the development of standards. Standards are extremely important for a wide-scale effort of international scope with a myriad of worldwide suppliers and customers. A coordinated joint standard helps avoid a hodgepodge of non-compatible requirements and hardware. When the effort is international in scope, it helps avoid the creation of unfair competitive elements. The mini-environment effort, in this case, was enhanced by the experience of the JESSI participants in multinational standards work and the sharing of experiences helped U.S. participants move up the learning curve quickly.
The mini-environment study was very successful and even led Sematech to reconsider part of its charter. Although the original scope was to serve members of the U.S. semiconductor industry, some areas and projects–where common advancement was in the best interest–were beyond the semiconductor industry, while other multinational projects were beneficial for everyone. The Sematech strategy now calls for global cooperation on standards, next wafer size, and environmental issues.
Future contamination control activities at Sematech continue to be under the direction of Dr. Venu Menon, manager of CFM activities, who says, “contamination control activities are now focusing on defect reduction in equipment, wafer environment control, monitoring wafer elimination, defect detection equipment, manufacturing research at Sandia National Laboratories, and materials and subsystems.”
Defect reduction in equipment continues to improve tool cleanliness targets, and provides an atmosphere of cooperation between suppliers and users on targets and standards. The wafer environment control provides a focus on wafer processing, while major efforts recently have been in mini-environments, this work can certainly encompass room enviro nments and micro-environments (clean environments within a tool which may or may not require a clean external environment).
Equipment for monitor wafer elimination and defect detection focuses on improved defect measurements on process wafers and in-process, rather than using expensive monitor wafer processing, which reduces manufacturing capacity and is very costly in high volume production. Research at Sandia National Laboratories will focus on contamination-free manufacturing improvements and will be jointly directed by Sematech and the department of energy. The materials and sub-system efforts will focus on materials science and its application to major systems and sub-systems like valves, switches, and plumbing.
Clearly, Sematech has been a joint government/industry activity. Last fall, Sematech announced it would become 100 percent industry-funded by 1997. Instead of receiving $180 million per year, funding will be reduced to $90 million per year from member companies. This has raised concern about the activities that will be provided by Sematech. Some Sematech observers say that because of the current success of Sematech and because of the establishment of the semiconductor technology council by Congress, the role of Sematech will continue to expand. They argue that while direct funds to Sematech will diminish, the actual funds that Sematech directs will greatly expand. Sematech may now be instrumental in guiding some of the billions of dollars that the government now spends in semiconductor research annually. The Sematech consortium can continue to help make this research more effective and more economical.n
Harold Fitch is president of Future Resource Development (Burlington, VT), a consulting firm that specializes in cleanroom education and problem-solving. He conducts international training seminars for CleanRooms` shows and seminars. He also writes the Cleanroom Management monthly column for CleanRooms magazine.
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U.S. and Japanese semiconductor marketshares are projected to be very far away from one another. By 1998, U.S. marketshare is projected to be below 25 percent, whereas Japanese marketshare is projected between 55 and 65 percent.
Sematech Centers of Excellence
Boston University
Carnegie Mellon University
Cornell University
Massachusetts Institute of Technology
North Carolina State University
Rensselaer Polytechnic Institute
Sandia National Laboratories
Stanford University
State University of New York
Texas A&M University
University of Arizona
University of California (Berkeley)
University of New Mexico
University of Texas (Austin)
University of Wisconsin (Madison)
University/Lab Research Participants
Arizona State University
Auburn University
Boston University
Cape Western Reserve University
Cornell University
Lehigh University
Massachusetts Institute of Technology
North Carolina State University
Northwestern University
Rutgers University
Sandia National Laboratory
University of California (LA, Berkeley, San Diego)
University of Florida
University of Illinois
University of New Mexico
University of North Texas
University of Washington
Development Contract Participants
ADE Corp.
American Telephone & Telegraph
Applied Materials
Asyst Technologies
Auto Soft Corp.
CFM Technologies Inc.
Consilium Associates Inc.
Dupont Photomasks Inc.
Eaton Corp.
Etec Systems Inc.
FSI International
Gasonics/IPC Inc.
Harris Semiconductors
Honeywell Inc.
Intel Corp.
International Business- Machines Corp.
ITP Systems Inc.
KLA Instruments
Lam Research Corp.
Louisiana Technical University
Martin Marietta (Energy Systems Div.)
Massachusetts Institute of Technology
Matric Integrated Systems Inc.
Metrologix Inc.
Micrion Corp.
Motorola
National Institute of Standards & Technology
National Semiconductor Corp.
Novellus Systems Inc.
Optical Specialties Inc.
Partnerwerks Inc.
Pennsylvania State University
Plasma & Materials- Technologies, Inc.
Prometrix Corp.
Quantronix
Relman Inc.
Research Triangle Institute
Rockwell International
Rodel Technologies Corp.
Rudolph Research Corp.
Sandia National Laboratory
SCI Systems
Semiconductor Research Corp.
Semitherm Inc.
Shipley Company Inc.
Silicon Valley Group Inc.
Sputtered Films Inc.
Systems Modeling Corp.
Technology Modeling- Associates
Texas A & M
Texas Instruments
University of Florida
Varian Associates
Weidlinger Associates
Wes Morris
Westech Systems Inc.
Wright, Williams & Kelley