Michael Gruver, Program Manager, IBM Engineering & Technology Solutions, gives his perspective on foundry customers and custom SOI design.
Michael Gruver: There are two primary areas that a customer should address if they intend to use IBM SOI technology.
The first is SOI-specific design education. SOI has electrical properties that must be accounted for such as the “history effect” and performance variations due to the “floating body” of the SOI transistor. IBM’s Engineering & Technology Services (E&TS) division offers a comprehensive set of education sessions to train individuals in the art of SOI design.
The second area is Tools & Methodology. As industry standard tools cannot directly simulate SOI floating body effects, IBM has a specialized simulator called POWERSPICE that also includes specific functions for analyzing the history effect. Static timing closure with SOI requires special handling. Other more obvious differences include specialized DRC (Design Rules Checking). Once again, IBM E&TS can work with clients to install and train them in the entire flow of tools used for custom SOI design.
ASN: Are there broader benefits beyond the straight performance boost that you tell your customers about that might make that investment worthwhile?
MG: SOI wafers are, in fact, more expensive than bulk. However, there are other variables that can offset this cost, such as smaller die sizes and less complex backend processes. This is especially the case for high-end chip designs where you are trying to gain the maximum frequency.
Of course all of these are trade-offs that need to be carefully understood and weighed. IBM E&TS has consulting services to help you with these decisions.