By Dr Mike Cooke
The International SEMATECH Manufacturing Initiative (ISMI) has launched a strategy to edge the semiconductor industry towards 450mm diameter wafers through piloting needed productivity enhancements on 300mm substrates. This comes at a time when Intel has been suggesting it might be looking to 450mm production around 2012 [e.g. presentation by Dr Mike Goldstein at Intel's 12th EMEA (Europe, Middle East, Africa) Academic Forum, Budapest, Hungary, 12-14 June 2007].

ISMI's existing 300mmPrime program will target productivity and cycle time improvements, and a new 450mm program will aim to drive down overall manufacturing costs. ISMI director Scott Kramer said the programs are designed for compatibility, with most cycle time improvements from 300mmPrime expected to be useful in 450 mm manufacturing.
"Our approach of converging 300mmPrime with 450mm aims to maximize efficiency and reduce the R&D burden on the industry, especially the supplier community," says Kramer.

The decision was based on nine months of intensive modeling of more than 130 full-factory, dynamic simulations and over 5000 hours of programming and analysis. These efforts asked if improvements from 300mmPrime alone could meet ISMI's goals of reducing manufacturing cost per area by 30% and cycle time by 50%. Tom Abell, manager of the 450mm program, reports: "The data shows that 300mmPrime has theoretical potential to achieve the targeted reduction in cycle time, but it does not sufficiently address our members' cost reduction needs. It appears that the key to significant wafer cost reduction can be found only in larger wafers."
According to Goldstein's presentation in June, meeting the cost reduction requirements of "Moore's Law", the industry benchmark for manufacturing and economic progress, requires an increase in wafer size every 4-5 generations (8-10 years?). The last step change (200mm to 300mm), however, took some 15 years to take place. Intel's 2012 proposal would give 12 years between the introductions of 300mm and 450mm, although 300mm had been mooted some years previous to 2000.

The revised ISMI 300mmPrime program will focus on areas that the models identified as having the greatest potential for reducing cycle time, including:
Reduction in first-wafer delay and set-up
Improvement in tool availability
Single wafer/mini-batch furnace process tools
The initiative's 450mm program will be organized this year and will pursue several goals in 2008, including:
Ensuring the availability of 450mm silicon wafers
Developing 450mm factory integration guidelines and standards
Creating a prototype test bed for 450mm factory integration
ISMI plans to immediately begin meetings with suppliers to discuss the implications and opportunities for 300mmPrime and 450mm. Additional steps will include continued development of next-generation factory guidelines and an update on detailed 450mm plans at the 4th ISMI Symposium on Manufacturing Effectiveness to be held 24-25 October 2007 in Austin, Texas.