Transitioning to 450 mm Wafers

Member companies of the International Sematech Manufacturing Initiative (ISMI) have reached a consensus on key concepts of a productivity improvement roadmap for moving the semiconductor industry toward 450 mm wafers.
 
ISMI's Guiding Principles for 300 mm Prime (300P), developed during several meetings this year and initially revealed at SEMICON Europa, are designed to minimize the cost and design challenges of 450 mm wafers, which ISMI's members see as inevitable for the industry.

"The Guiding Principles will be used as a foundation for gathering specifics on productivity designs, attributes and metrics to be pursued in today's 300 mm fabs, which will help pave the way to 450 mm implementations," said Scott Kramer, ISMI director.

Added Joe Draina, ISMI associate director, "300 Prime is a strategy for improving 300 mm productivity while bridging to eventual 450 mm manufacturing. This strategy draws on lessons learned from our industry's last conversion from 200 mm, and recognizes the importance of collaboration, consensus-building, and compromise among chipmakers and equipment suppliers."

Noting that 300P has attracted wide attention since ISMI introduced the concept in January, Kramer elaborated on the program's key concepts — 300P design and architecture must be forward-compatible with the 450 mm factory. Specifically, 300P productivity enhancements must be scaleable to 450 mm, with minimal changes in design and architecture; be tested and proven within a 300 mm setting; and demonstrate an acceptable return on investment.

Scenarios for 300P and 450 mm must be subjected to business modeling. Multiple-use manufacturing models need to be addressed, including high- and low-volume product mixes and multiple flexible lot sizes operating within acceptable cycle times.

300P developments will be an evolutionary process. Furthermore, some current 300 mm productivity improvements will be coordinated and deployed in 300P or 450 mm fabs.

"The introduction of 300P is designed to be an iterative and self-testing process that will generate immediate, mid-term and long-term benefits for the industry," Kramer said. "We see it as a gradual and affordable transition that is responsive to its participants and adaptable to their needs. As I've said before, this process is a marathon, not a sprint."

The latest version of the International Technology Roadmap for Semiconductors (ITRS) pulled in the introduction of 450 mm wafers from 2015 to 2012. Motivation for the newly indicated timing is driven chiefly by productivity enhancements suitable for keeping pace with Moore's Law. "Migration to the next diameter wafer has historically been occurring roughly on a 9-11 year cycle," noted the ITRS. "Accordingly, this means that to meet the newly stated timing, the industry is already several years behind schedule. Furthermore, a number of highly coordinated actions, such as setting standards, need to occur before any actual product/equipment development can be initiated. In contradistinction to even the 300 mm transition, which mainly focused on economic issues, the transition to 450 mm faces both enormous technical challenges and economic risk. Initially, the industry must adopt numerous interrelated standards, involving wafers, metrology, and processing equipment."

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