450 mm Polished Single Crystal Silicon Wafer Specification
By Kevin Nguyen, SEMI Standards
SEMI M1-1111 - Specification for Polished Single Crystal Silicon Wafers was revised and published in November 2011. The new edition includes a significant addition of a 450 mm polished single crystal polished wafer specification. Today, the specification requirements for 450 mm diameter wafers are much more extensive that those of previous smaller diameters. Standardized parameters include edge profile, warp, conductivity, dopant, and surface conditions.
To provide some context about history, SEMI M1 was originally published in 1980s. The first wafer specification was 50 mm (2 inch) or about the width of credit card. Over the years, wafers got larger and larger. In the early 1990s, the wafer size was increased to 200 mm (8 inch), and in 1997, the 300 mm (12 inch) wafer was standardized. A 300 mm wafer may yield 2.25 times more chips per wafer than an older 200 mm wafer. For 450 mm, 5 times more chips per wafer can be squeezed out of a wafer compared to that of 200 mm wafer, yet the process of making the chip takes about the same amount of time to go through the factory. More chips are produced per wafer, which in turns reduces the cost. Thus wafer manufacturers and users are moving ahead to formalize a specification for 450 mm wafer. The International Polished Wafer Task Force will continue to refine associated parameters to adapt to the dynamic semiconductor industry.
Despite the staggering cost of a 450 mm fab several announcements have been made recently. Intel announced that its D1X fab in Oregon will be 450 mm compatible (2013). TSMC announced a 450 mm pilot line by 2013-2014. IMEC and ISMI have well-established programs focused on the challenges posed by manufacturing with 450 mm wafers and the University of Albany's College of Nanoscale Science and Engineering (CNSE) is expanding facilities to encompass 450 program R&D. [Source: Perspective on 450mm]. Nevertheless, tool vendors are continuing to show 450 mm generation capability products and some device manufacturers are upgrading their fabs.
SEMI Standards task forces are working on encouraging the industry to collaborate 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 and has published twelve 450 mm standards with 10 more in the pipeline.
If you have any questions, or would like to participate in SEMI Standards activities for 450, contact your regional SEMI staff.
SEMI Standards Watch, March 2012