Test Trends: Commercial Scan Compression Tools
About a dozen years ago, the world of test had reached an economic impasse: most digital designs had become sufficiently complex that standard scan testing techniques were no longer cost-effective. Because scan chains were too long, it was taking too much time to scan data through them when applying manufacturing tests. Moreover, even though at-speed testing had become essential for screening nanometer defects, many low-cost and legacy testers did not have the memory capacity to store all the data.
The emergence of commercial scan compression tools at that juncture changed the economics of test. Instead of connecting flops together into a few very long scan chains, they created hundreds of short chains connected to a compressor-decompressor (CODEC). Compression enabled substantial cost savings through test application time reduction (TATR) and test data volume reduction (TDVR). TATR lowered costs for semiconductor manufacturers testing parts in high volume because more parts could be tested in less time. TDVR reduced memory storage requirements to accommodate both stuck-at and at-speed tests to improve defect coverage.
Full article by Chris Allsup, EDN Network
About the Author
Roger Chu is the Marketing Coordinator at GSAmart, the leading GSA sales and marketing partner for technology companies.
