Yield Loss — It's Not All Process Defects

摘要

Major yield detractors occur in various fab process steps as well as in design marginalises. But the test process itself can be a yield detractor, causing upwards of 5°/o of good product loss in some cases. Negative impact of test can go undetected no matter where you are on the yield curve. Although subtle issues in test can cause false rejections, yield loss from the test floor can be controlled. This article outlines a systematic approach to improving test yields, which involves: assuring the integrity of test data, the generation of test process rules, and detecting/eradicating errors in the hardware and software of test cells using test management software.