More Asian participation needed to develop global SEMI standards
08/01/1998
More Asian participation needed to develop global SEMI standards?
William A. Brown, W. Murray Bullis, Semiconductor Equipment and Materials International (Semi), Mountain View, California
The benefits of semiconductor industry standards are known in Asia. But Asian technologists outside of Japan have had a limited role in standards development. Recent outreach efforts by SEMI have sought to engage more of these individuals in the process. New enhancements to SEMI`s standards program, including video conferencing, will make regional participation easier and more productive.
This year is the 25th anniversary of the International Standards Program at Semiconductor Equipment and Materials International (SEMI). The program is a key element in the service offerings from SEMI, which is best known for its SEMICON exhibitions held around the world.
SEMI standards are voluntary technical agreements between suppliers and their customers, aimed at improving product quality, reliability, and interchangeability at a reasonable price. They are written specs, test methods, guides, terminology, practices, etc., for the materials, equipment, and services used in the worldwide semiconductor and flat panel display (FPD) industries. Several hundred standards are now in print with most having influence on industry operations.
SEMI provides the framework so that experts representing suppliers, users, and other interested groups can develop standards in a neutral environment. At the present time, over 3000 individuals around the world participate in the development of SEMI standards. However, despite the rapid semiconductor and FPD growth in the Asian Rim, outside of Japan, only about 3% of standards program membership is based in this region. In fact, all SEMI standards to date have been developed by committees organized in North America, Japan, and Europe (Fig.1).
This is not to say that SEMI standards have been invisible to technologists in Asia. They have seen them cited in equipment and materials quotations, heard about them at technical conferences, and used them in many of the functional areas related to semiconductor or FPD manufacturing. As we will discuss, SEMI standards have been highly beneficial in the development of these industries, but the most important benefits to individuals are in the development process itself.
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Figure 1. Worldwide SEMI standards membership.
Importance of SEMI standards
SEMI standards cover every aspect of semiconductor and FPD manufacturing, including substrates, chemicals, gases, equipment, factory communications, traceability, microlithography, facilities, and packaging. In addition, SEMI guidelines are also developed to cover safety-related issues.
The SEMI specification for the dimensions of silicon wafers (SEMI M1) was the first standard developed by the industry under SEMI auspices. This standard, introduced at the time the industry was beginning its transition to 75-mm wafers, has been continually updated during the intervening years. Its importance is illustrated by the statement in the 1994 National Technology Roadmap for Semiconductors that the industry must select the next wafer size following 200 mm, so resources will not be squandered on equipment for multiple wafer diameters, only one of which would be used in production [1]. This challenge led to the development of specs for 300-mm developmental, test, and prime wafers (SEMI M28, SEMI M8.12, and SEMI M1.15) during the past few years.
In 1980, SECS, the SEMI equipment communication standard (SEMI E4 ), was published. This standard defined a communication interface suitable for exchange of messages between semiconductor processing equipment and a host computer. This was followed a few years later by SECS-II (SEMI E5), which provides detailed message protocols. SEMI E5 forms the underpinning for present-day information and control systems in semiconductor factories. Subsequently, these standards were joined by many others, including GEM, the generic equipment model specification (SEMI E30), and HSMS, the high-speed messaging system standard (SEMI E37), that provide factory automation protocols.
Another widely used SEMI standard (SEMI E10) provides standardized definitions of terms that characterize reliability, availability, and maintainability (RAM) of semiconductor process equipment. This document has recently been joined by a new one that allows automated collection of the RAM data (SEMI E58). This capability will be very important for fully automated 300-mm wafer factories.
The well-known guideline (SEMI S2) for evaluating the safety aspects of semiconductor equipment during the design and development phase, revised in 1993, has been effectively applied by a number of semiconductor manufacturers who realized considerable reduction in cost and time of equipment installation by its application. Subsequently, its provisions have been written into the codes of a number of local jurisdictions in which IC factories are being constructed, thus aiding in assuring the safety of these factories for both workers and communities.
These and the other standards and safety guidelines developed within the SEMI standards program have proved to be of value to the global semiconductor industry through savings in tool set costs, standardized automation protocols, and improved clarity in materials specs. Now, with the very large costs anticipated to implement the transition to 300-mm wafers, the industry has recognized the importance of standardization of common elements to reduce unnecessary duplication and customization of equipment. There has been an unprecedented interest among semiconductor manufacturers in defining common requirements for new factories that will be required for 300-mm production. At the same time, the need to generate standards before processes are fully developed gives the standards community the opportunity to provide some of the necessary understanding.
For those who participate in the development of these standards, the personal benefits may exceed the value of the written document. Participants gain increased awareness of industry issues, broaden their personal networks, and realize the satisfaction of helping the industry achieve increased efficiency and economies. In addition, their companies benefit from state-of-the-art technical discussions.
Association expansion in Asia
SEMI has conducted trade shows and programs internationally since 1975, but it did not become an international trade association until the mid-80s when it opened offices in Europe and Japan. The Korean office opened in 1990, and offices later opened in Singapore (1993) and Taiwan (1995). These offices coordinated annual trade shows, technical programs, industry forecasting seminars, and other events in their local regions. They also distributed SEMI standards and fostered their use. Although a few individuals in these regions signed up to participate in the standards program, the level of participation has remained low.
The Peoples Republic of China has been involved with the use of SEMI standards since the late 1980s, when the China State Bureau of Technical Supervision (CSBTS) established the SEMI China Standards Committee (SCSC) to coordinate activities related to SEMI standards in China. CSBTS undertook the translation and distribution of SEMI standards to domestic factories and research institutes. The SCSC has concentrated on standards related to materials (i.e., silicon and gallium arsenide), chemicals and gases, and packaging. China has adopted, and in some cases adapted, SEMI standards in these areas for use as national standards to meet the specific needs of the Chinese semiconductor industry.
During the last decade, SEMI expanded its standards staff to support standards development work in North America, Japan, and Europe. Today, fourteen staff members in Mountain View support both the overall program functions and the North American document development, and eleven staff members in Tokyo support document development in Japan. There is also a standards coordinator for Europe in the Brussels office. Last year, a standards engineer for Korea was added to the Seoul office to help establish and support standards development work there. This was the first direct local support activity for SEMI Standards in Asia outside Japan.
Standards outreach in the Asian Rim
During the past several years, outreach efforts from SEMI`s Mountain View, CA, headquarters were initiated to increase awareness of the benefits of participation in standards development. The most effective mechanism for doing this is standards technical education programs (STEPs). These programs provide information about the development and application of SEMI standards presented by key participants in the process. Thus, they provide both insight into the process and examples of real applications, as well as face-to-face contact with active standards committee members.
Programs on equipment safety and chip traceability have been presented in connection with SEMICON test, assembly, and packaging in Singapore during the past few years. The first of these focused on SEMI S2 and the current activity to revise and extend the scope of this safety guideline to environmental as well as safety issues. The second considered the standards that would be needed to provide die traceability forward through packaging and back through front-end processing to the starting wafer. These programs elicited solid interest but gained only a few new participants in the program.
In Korea, similar results were obtained from two STEPs conducted in connection with SEMICON Korea earlier this year. These STEPs focused on factory communications and equipment safety. The first provided a general overview of the various SEMI factory communications standards and their applications. It also included discussions of the computer integrated manufacturing framework, based on work conducted at SEMATECH during the last few years and now being developed as a series of SEMI standards and other publications. The second concentrated on ways in which both equipment manufacturers and IC manufacturers have benefited from SEMI S2, and on the use and qualification of third-party evaluators called for in the guideline.
In connection with SEMICON Taiwan in 1997, two STEPs were conducted in Hsinchu Science Park, the concentration point for most semiconductor and FPD activity in Taiwan. One of these STEPs, organized by SEMI Japan, dealt with current developments in carrier and interface standards for 300-mm factories. These standards, developed in close coordination with I300I in the US and J300 in Japan, describe the kinematic couplings necessary to provide more accurate alignment of cassettes, pods, and boxes in 300-mm equipment-a 25- or 13-wafer cassette, a standard mechanical interface and box with separate cassette, a front-opening unified pod with integral cassette, a box opener-loader to tool standard, a cart-to-tool docking standard, and an equipment tool load-port located a fixed height above the factory floor (see Fig. 3 on p. S34). The second STEP dealt with the development and application of SEMI E10 and automated data collection, as well as current extensions of these principles to cluster tools. Again, there were many questions, but only limited interest in actually contributing to the development of SEMI standards.
Subsequent activity in cooperation with the Taiwan Semiconductor Industry Association included a seminar this past spring that detailed the various ways individuals and companies could participate in SEMI standards development activities.
How to participate
Any qualified individual associated with the semiconductor or FPD industries worldwide is entitled to participate in the SEMI International Standards Program. Although SEMI is an association of suppliers to these industries, the Standards Program has always been open to customers (i.e., "users") and other related organizations, as well as suppliers. SEMI charges no fees for participation in the program.
At present, the program consists of 21 global technical committees covering many aspects of semiconductor and FPD manufacturing (Fig. 2). These committees are responsible for developing the industry consensus leading to the publication of SEMI standards.
Each committee is comprised of one or more regional technical committees. At present, these regional committees are based in Europe, Japan, or North America. Committee members can participate in the activities of any of the regional committees.
Individuals become members of the technical committees by completing a membership application, available from any SEMI office. The application provides the contact information for SEMI to furnish meeting announcements and notices of upcoming events, meeting minutes, and other information. It also identifies the voting status of each member for ballot actions.
Technical committees establish task forces to develop draft documents. The direction of the industry can be influenced in task force and committee discussions; this is a key point where new technology is discussed. This is also the entry point for Asian members to represent their companys` interests. Members can participate in task forces and attend committee meetings (usually held concurrently with a SEMICON exhibition) either in person or by teleconference or video conference when such facilities are available.
Voting is the last step in the consensus-building process. After a committee reaches informal consensus in meetings, it issues a worldwide letter ballot to ensure that every voting member of the program can critique and comment on the document. To be successful, the balloted draft must meet specified requirements for return rate (based on the voting roster of the committee at the time the ballot is issued) and for minimum acceptance and maximum rejection rates (based on all valid votes received).
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Figure 2. SEMI standards organization.
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Figure 3. SEMI interface and automation standards. (Source: I300I)
Although individuals anywhere in the world can participate in the program separately, it is recommended that those having a common technical interest within a certain geographic area band together in an informal working group under the auspices of the local SEMI office. Group members can comment and vote on documents as individuals, but the group may be able to exert more influence by developing common positions that could be represented in task force discussions or committee meetings through the attendance of one or more group members.
When there are enough members with common interests in a region, formation of a regional technical committee may be proposed to the International Standards Committee, the governing body of the program. Two requirements for forming a regional technical committee are that there must be supplier members in the group, and a SEMI Standards Program staff member must be in attendance at all meetings of the committee.
The local SEMI staff will assist working groups in becoming regional technical committees in consultation with the program development staff in Mountain View. In addition to working on documents initiated elsewhere, regional technical committees may establish task forces, initiate documents, and authorize letter ballots.
Future directions
SEMI is working to improve access to its standards program through the use of the Internet, e-mail, and video conferencing for document development/distribution. Some task forces are using local web servers to post draft documents (with SEMI approval) for review and development.
Video-conferencing facilities have been established in SEMI`s Mountain View and Tokyo offices; this capability is being extended to other SEMI offices. Electronic distribution of meeting announcements, minutes, and surveys will be initiated during 1999, and electronic document development activity on the SEMI web site is planned for the following year.
Conclusion
Historically, the SEMI standards program has influenced the course of the semiconductor and FPD industries. This is even truer today as the 300-mm transition unfolds. Recent and pending program enhancements will make it easier for participation in the standards development process. Thus, it is most timely for regions with rapidly growing semiconductor and FPD activity, including all of Asia, to play a significant role in the development and utilization of SEMI standards. Asian technologists can continue to accept the results developed elsewhere in the industry or they can actively participate in the program to help shape future standards.
Acknowledgment
SEMI and SEMICON are registered trademarks of Semiconductor Equipment and Materials International.
References
1. The National Technology Roadmap for Semiconductors, Semiconductor Industry Association, 1994, updated, 1997.
WILLIAM A. BROWN received his BS in chemistry from Niagara University and his MS in metallurgical engineering from Rensselaer Polytechnic Institute. He has served in a variety of manufacturing and technical positions at IBM and other companies. Brown is manager of program development at SEMI International Standards Program, 805 E. Middlefield Rd., Mountain View, CA 94043; ph 415/964-5111, fax 415/967-5375.
W. MURRAY BULLIS received his PhD in physics from Massachusetts Institute of Technology. Since 1964, he has worked in silicon materials technology and metrology for semiconductor device and materials manufacturing at such companies as Siltec, Fairchild Research Lab, National Bureau of Standards, TI, and in his own consulting business. Bullis is VP for International Standards at SEMI.