Mentor Adds Yield Diagnostics to DFM Toolset

Aimed at allowing fast and accurate identification and isolation of yield-limiting defects, Mentor Graphics Corp. today unveiled the YieldAssist diagnostic tool, part of its design-for-test (DFT) product family.

Since accurate diagnosis of scan test failures is a critical element of failure

analysis, and is becoming vital for yield learning and yield improvement purposes as nanometer technologies continue to shrink, the tool was designed to take failure information directly from manufacturing test failures and feed it back to the manufacturing or design team to facilitate yield learning and eliminate manual analysis effort through the use of advanced diagnostics, the company explained.

Improving yield in the nanometer era requires solutions that span all aspects of the design to manufacturing flow, and as such, failing devices from the wafer sort phase of manufacturing test can provide a goldmine of information for yield and failure analysis engineers, Mentor said.

The YieldAssist tool allows semiconductor manufacturers to collect this information and identify systematic and random defects for failure analysis and yield improvement, along with providing a critical link back into the design process to improve design for manufacturability as well as for adaptively improving the quality of the manufacturing test itself and reducing defect per million rates.

The overall yield learning/monitoring strategy that YieldAssist facilitates addresses the three key areas needed for a complete solution; high quality test, effective defect isolation and rapid high-volume diagnosis.

Effective detection of all the subtle defects that occur in nanometer designs is the first step in yield improvement, the Wilsonville, Ore.-based company noted.

Manufacturing tests created with Mentor’s TestKompress or FastScan automatic test program generation tools provide the foundation for improving defect detection and diagnosis. Then, using the failure data from manufacturing test, YieldAssist isolates the cause of the failure and map it to defect suspects.

The tool then links to Mentor’s Calibre results viewing environment allows users to view suspected defects in the physical design layout view to further isolate problems down to a physical feature.

Rapid high-volume diagnosis in a production environment is allowed by the tools ability to directly read failure logs from compressed test patterns for effective failure diagnosis directly from production test data, avoiding the additional cost of rerunning special tests for diagnosis purposes only, as other tools require.

The YieldAssist tool is available now.