The virtues of collaboration in the extraordinarily complex and capital-intensive business of microelectronic technology development have been long recognized and are only becoming more important as transition to manufacturing on 450 mm wafers accelerates.
Industry Alignment on Cost and Time Savings in the 450 mm Transition
Jonathan Davis,1 Frank Robertson,2 Allen Ware3
1SEMI 2G450C 3M+W Group
The virtues of collaboration in the extraordinarily complex and capital–intensive business of microelectronic technology development have been long recognized and are only becoming more important as transition to manufacturing on 450 mm wafers accelerates.
Commercial wafer fabs are dependent on intricate synchronization and interoperability of hardware, software and other technology that is provided from numerous companies around the world. Both chipmakers and their suppliers benefit from coordinated planning activity. Consequently, the industry has developed many ways to achieve alignment and efficiency, including roadmaps, consortia–facilitated activity and standards development, to name just a few.
Formation of the Global 450mm Consortium (G450C), announced by Governor Andrew Cuomo in September 2011 and based at the College of Nanoscale Science and Engineering (CNSE) in Albany, N.Y. (Figure 1), provided a clearer sense of customer commitment to 450 mm development. It also represented significant opportunity to increase levels of collaboration as the semiconductor industry implements the capability to manufacture its products on larger wafers.
Figure 1. The G450C is based at the College of Nanscale Science and Engineering in Albany, N.Y.
By agreeing early in the transition on elements of chipmaking operations ranging from interoperable physical interfaces and components to streamlined methods for installation, the industry can save time and money. Another example of collaborative dialog is seen with the Facilities 450mm Consortium (F450C), a consortium formed in collaboration with G450C to focus on facilities and fab installation issues.
Standardization contributes to the efficiency of the industry in ways that provide significant benefits to all participants. A 2007 National Institute of Standards and Technology (NIST) study estimated $9.6 billion in benefits between 1996 and 2011 from standard test methods and software standards.
One of the most highly respected and effective platforms for semiconductor manufacturing technology collaboration occurs under the purview of SEMI Standards. This international consensus–based program was established in 1973, with clear procedures and attention to anti–trust, copyright and intellectual property sensitivities. To foster openness, transparency and inclusion, SEMI Standards activities are open to all interested parties, including chip manufacturers, suppliers, trade organizations and government agencies. Worldwide distribution of document drafts and ballots facilitates global consensus–building and helps achieve a common alignment toward complex technology development.
Standardization is strongly motivated by the need to establish consistent definitions and specifications that can be relied upon to function over time. However, standards are not static. They adapt and are revised as new learning occurs.
Over the past 40 years, all aspects of an automated fab have been addressed through a structure that includes thousands of industry volunteers, 23 global technical committees and 200 task forces. This formidable infrastructure has resulted in the current availability of more than 800 SEMI Standards and Safety Guidelines that are globally accessible through SEMIViews, a comprehensive online repository and document management tool.
Learning From the 300 mm Experience
At the last wafer size transition, a number of standards for physical interfaces and carriers were defined before prototypes were available, or in some cases before component concepts were firmed up. Despite good intentions to provide design frameworks, the lack of data on functionality, reliability and interoperability led to repeated modifications of the standards and an extended period before they were finalized.
Industry adoption of new standards depends on a critical mass of customer support and adequate implementation guidance (Figure 2). SEMI F107 for an Adaptor Plate was defined at 300 mm with the intent to enable pre–facilitating and rapid installation of fab equipment; it was not widely specified by customers, and suppliers did not generally ship the adaptor plates ahead of the tools to pre–install. The transition to 450 mm presents an opportunity to improve the implementation of templates for time and cost savings.
Figure 2. Industry adoption of new standards depends on a critical mass of customer support and adequate implementation guidance.
A major emphasis on environmental objectives and compliance with safety and ergonomics standards occurred during the 300 mm wafer transition. It resulted in increased attention to these elements during the design and certification of new tools. It is critical that these focus areas continue to be emphasized going forward. Compliance with SEMI EHS Guidelines, including S2 (EHS Guidelines for Semiconductor Manufacturing Equipment) and S8 (EHS Guidelines for Ergonomics Engineering) will again be a required part of demonstrations at G450C.
Even where international standards already exist, there is potential to improve compliance and implementation, and learning from pilot projects on new concepts may lead to new standards. Where standards are not yet established, consortial working groups help focus industry priories.
Collaboration on 450 mm Standards
Guided by customer requirements, SEMI Standards task forces are working on key issues such as the technical parameters for 450 mm silicon wafers, physical interfaces, carriers, assembly and packaging. To date, SEMI has 10 task forces working on 450 mm, and has published 15 450 mm standards with 16 more in the pipeline.
The Specification for Polished Single Crystal Silicon Wafers (SEMI M1–0812) was revised and published in August 2012. The new edition includes a significant addition of a 450 mm polished single–crystal silicon wafer specification and the guide for specifying 450 mm wafer for 32, 22 and 16 nm technology generations. Standardized parameters include edge profile, warp, conductivity, dopant and surface conditions.
Industry alignment on the dimensions for wafer thickness and carrier slot pitch was an early success for 450 mm. The agreement on 925 vs. 825 µm thickness, which was extrapolated from the recent diameter increase thickness trend, represented a compromise between customer drive for the thinnest and lowest–cost wafer possible and supplier concerns on robustness in handling. The 2 mm increase in wafer spacing to 12 mm balanced margin for gravitational sag and process–induced warpage with carrier volume and productivity. In both cases, significant test data was brought to bear on the industry's deliberations, and standards were set in a timely manner.
To ensure viable factory integration solutions up front, leading proponents of 450 mm worked with suppliers during early co–development of component prototypes and international standards to run many millions of cycles of individual and interoperating components (wafers, carriers, load ports, wafer handling robotics), feeding data requested by SEMI's volunteers into the engineering assessment for standards. The overall result was a reduction in the time to finalize the standards of about 60% compared with the equivalent duration for 300 mm.
Based on this proven effectiveness, the G450C program will use SEMI–standard wafers and carriers and verify compliance with a broad set of SEMI standards for physical interfaces and factory connectivity in 450 mm equipment demonstrations.
Figure 3. The time it took to finalize 450 mm standards was only 60% what it took for 300 mm standards.
Figure 4. A number of groups working on 450 mm have indentified key issues and are aligning on approaches to address them.
Further Standardization Opportunities
A number of groups working on 450 mm have identified key issues and are aligning on approaches to address them (Figure 4). Some equipment companies have provided insight on components for potential standardization while the F450C proposed a number of projects for consideration. G450C's Facilities Council and Standardization Working Group prioritized a short list from these opportunities for immediate action, and plans are being defined for rapid initiation.
Bringing 450 mm to reality is not only a daunting task from a technical and manufacturing standpoint, but as we consider the facility infrastructure it becomes apparent that merely scaling the new facility is not a practical option. The size of the 450 mm facility superstructure and related infrastructure consumption projections will simply exceed affordability realities or resource availability constraints.
These roadblocks can be addressed only through standardized solutions developed in collaboration with facility experts across the entire supply chain (Figure 5). M+W, as a leading design/builder of technical facilities, in consultation with G450C, has begun to coordinate with premier semiconductor facility companies around the globe to bring their collective expertise to bear on the most pressing facility issues. These collective companies form F450C.
Figure 5. Bringing 450 mm to reality will require not just a mere scaling of facilities.
Based on discussions to date, suppliers' and IC makers' priorities for pre–competitive cooperation include:
- Pilot projects: "hoist" survey; wet station utilities' actual use to minimize over–engineering; etcher consolidated points of use; and adaptor plate installation.
- Supplier requests for customer convergence: uniform safety sign–off; consistency of procurement documentation; reduced range of fab layout/equipment configurations.
- Materials conservation imperatives related to technology trends in timeframe of 450 mm (e.g., helium capture); pump idle mode.
Multiple parties are engaged in discussion of further standardization opportunities among global organizations. There is agreement between G450C and groups in Europe and Israel on harmonizing contamination requirements at both the tool and facility levels. SEMI regional working groups have also proposed further development of standards for predictive carrier logistics, secure recipe management and a recess for longer–stroke load port robot to enable higher wafer transport plane in 450 mm tool platforms. There is also industry–wide support for further detailing industry EHS best practices to help with sustainability.
Progress on the transition to 450 mm wafers is being made with a variety of collaborative engagements among consortia, standards bodies and industry representatives from the IC makers, and equipment and materials companies. Consortia activity will drive industry agreement on a focused set of early concepts that can be designed in to save time and money, and reduce risk, in developing and deploying 450 mm capability.
The SEMI Standards program allows companies to collaborate in a pre–competitive environment to codify specifications, definitions and guidelines that result in greater industry efficiency. Together, the industry will be learning from the past and looking to the future as the prospects of manufacturing semiconductors on 450 mm wafers gains momentum.
About the Authors
Jonathan Davis is global vice president of advocacy and a member of the Global Executive Team at SEMI. Davis has served at SEMI for more than 20 years in various management positions, including president of the Semiconductor Business Unit; president of SEMI North America; and executive vice president of global expositions, communications, marketing and EHS.
Frank Robertson is vice president and general manager, industry interface and program strategy at the Global 450mm Consortium (G450C). He began work on the 450 mm transition in 2005 while managing external programs for Intel, assuming his current position as an assignee at the founding of G450C in 2012. Prior to joining Intel in 2000, Robertson had been chief operating officer of International SEMATECH and general manager of I300I.
Allen Ware is vice president, program executive for the 450 mm consortium for M+W U.S. Inc. He joined M+W Group in September 2011, having previously worked at Intel as director, facilities materials & services. He is retired from the U.S. Army, where he served in a variety of Corps of Engineers assignments. n