P A P E R    T I T L E
Economic Justification of a 6" GaAs Wafer Fab

A U T H O R  /  C R E D I T S
Jerry Gedaly
Raytheon Company
advance Device Center Andover, Massachusetts

A B S T R A C T
The demand for high speed Gallium Arsenide (GaAs) products has increased such that the technology is expanding beyond niche markets and is entering commodity markets. The ultimate acceptance of GaAs in commercial applications, however, depends upon its providing the lowest cost solution compared to other technologies.

To achieve lowest manufacturing costs, many GaAs companies have embraced the "Silicon Model", which continually increases wafer diameter. Over the last ten years, GaAs wafer sizes have increased at a rate equal to one-half the diameter of the typical silicon wafer. GaAs conversion to 6" is occurring simultaneously with Silicon conversion to 12" wafers.

Justification for conversion to a larger wafer size in a "moderate volume" GaAs fab is based upon economic arguments which consider Total Cost. To do this, the "arguments" are converted to algorithm-based cost models, which take into account existing conditions and predict future outcomes prior to expenditures.

The characteristics of the moderate volume Gallium Arsenide wafer fab include: low overall capital utilization, single points of failure, and low operator productivity. In spite of these disadvantages, the cost advantage of larger wafer sizes can be demonstrated. Modeling steers process, equipment, and staffing decisions that must be made to achieve optimal operating metrics.