Mentor tips plans for unified Si test, yield analysis
Mentor Graphics is launching what it calls a comprehensive test and yield analysis platform to help customers drill down through failure analysis data to better identify and fix defects, thus saving time and improving yields.
The plan combines Mentor's embedded compression and automatic test pattern generation (ATPG) technology with the built-in self-test (BIST) technology for memory and logic acquired with LogicVision in May 2009. The new product line, Tessent, incorporates a Diagnosis tool for automated scan test failure collection and diagnosis, and a new YieldInsight product to analyze/visualize and drill-down through large volumes of production test failure diagnosis data. Also included are silicon debug/characterization (LogicVision's SiliconInsight product) and layout-aware diagnosis (via Mentor's tools).
The Diagnosis software performs volume diagnosis of manufacturing test failures (based on FastScan or TestKompress scan patterns), providing information beyond single-device defect location to classify all major defect mechanisms, and uses layout information to identify physical features and cell types associated with a defect type (e.g., attributes ranging from via type to metal layer and failing scan cells). Diagnosis results are compared to expected distribution to help spot patterns in the failure diagnosis data that might point to systematic issues. Further analysis helps understand the impact of each systematic problem and select devices for physical failure analysis that clearly exhibit the identified problem.
As an example, the company described a customer performing signature analysis on failure diagnosis data indicated a systematic issue contributed to yield loss, further identified as a single defective via on Layer 5. A manufacturing process change was made to correct the issue and eliminate future yield excursions.
Going forward, Mentor's BIST offerings will be based on the former LogicVision platform, and test-pattern generation will be based on Mentor's TestKompress and FastScan platform; some of Mentor's former BIST products, and LogicVision's ATPG products, will be discontinued. Mentor said it will invest and develop mixed-signal BIST for Serdes and PLL testing as well as LogicVision's SiliconInsight line, and will seek to add more functionality to the Tessent line for "emerging challenges related to test." —J.M.