S/390 G5 CMOS microprocessor diagnostics

This paper describes the strategies and techniques used to diagnose failures in the IBM 600-MHz S/390® G5 (Generation 5) CMOS microprocessor and the associated cache chips. The complexity, density, cycle time, and technology issues related to the hardware, coupled with time-to-market requirements, have necessitated a quick diagnostic turnaround time. Beginning with the first prototype of the G5 microprocessor chip, intense chip diagnostics and physical failure analysis (PFA) have successfully identified the root causes of many failures, including process, design, and random manufacturing defects. In this paper, three different diagnostic techniques are described that have enabled the G5 to achieve its objective. An example is presented for each technique to demonstrate its effectiveness.