ASIC jeopardy-diagnosing without a FAB

In IC diagnosis, failure information is used to isolate the defect to a small set of potential locations, then probing techniques are used to find the actual defect site. Our diagnosis problem is a lot more messy. By definition, the NTF (No Trouble Found) IC fails only at board or system test, making the use of standard IC level diagnostic tools impossible. Sun is fabless, so we do not know common failure modes, have no indication of process and yield history, and don´t have access to information that might give a clue as to the cause of failure. The result of diagnosis is an IC test that can detect the failing part, or an understanding of the root cause of the failure sufficient to correct the underlying problem. Since there are so many potential causes of NTFs, the best one can do is develop a set of suggestions for resolving them. Some things that seem to work, at least sometimes, are presented