Get more from your test compression: VersaPoint test point technology

By Jeff Mayer – Mentor, A Siemens Business

Is your test pattern count running away with your profit margins?  Are you looking for higher compression levels out of your test implementation than you’re able to achieve with compression alone? 

There is no escaping the trends in the semiconductor industry that lead to increased IC test data volumes, longer test application times, and higher test costs. But, there are new strategies and technologies to manage these challenges to the bottom line. The latest boost to reducing test data sets is VersaPoint™ test point technology.

What is VersaPoint™? It is a new type of test point that allows users to target both ATPG pattern count reduction and LBIST test coverage improvements in a single test point insertion pass. Why is this important? Because of the rapid adoption, especially among mission-critical ICs used for automotive applications, of a Hybrid ATPG/logic built-in self-test (LBIST) strategy. The once-separate ATPG and LBIST technologies have merged to the point where compression IP is being re-used to apply BIST tests. The result is smaller test sets, higher fault coverage, and the integration of self-test required by the functional safety standard ISO 26262.

Test points are dedicated design structures used to improve the test results. Traditional LBIST test points improve results by addressing random pattern resistance in ICs. Mentor previously developed test points specifically for on-chip compression/ATPG, which reduces ATPG pattern count by 2-4X above what is achieved with on-chip compression alone.

However, if you have a Hybrid ATPG/LBIST methodology, don’t you also want a more efficient test point insertion strategy? That’s where VersaPoint™ test point technology comes in; it combines and improves upon previous test point algorithms.

Say you get 46X compression with Tessent TestKompress, why not go for an additional 2-4X on top of that, which is what we’ve seen in experiments using VersaPoint technology on industrial designs. VersaPoint™ test points work with Hybrid ATPG/LBIST with more efficiency than test points for either ATPG or LBIST separately. Test points that target both scan compression and BIST significantly cut test time and cost with no loss of coverage.

To learn a lot more about VersaPoint™ technology, download this new whitepaper, Improving Test Pattern Compression with Tessent VersaPoint Test Point Technology. This paper explains how VersaPoint™ test points work and includes experimental data from industrial designs demonstrating pattern count reduction with VersaPoint™ technology.

VersaPoint™ test points are currently in use at several large semiconductor companies as replacements for separate LBIST and ATPG test point insertion in Hybrid ATPG/LBIST testing strategies. All are finding the run-times of the newer algorithms are far faster than previous LBIST test point algorithms, providing savings of 20X on average.

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This article first appeared on the Siemens Digital Industries Software blog at https://blogs.sw.siemens.com/tessent/2017/12/01/get-more-from-your-test-compression-versapoint-test-point-technology/