The Importance of Functional-Like Access for Memory Test

Memory test debug is a challenging problem due to a vast number of variable parameters that make it difficult to pinpoint root cause. Programmable built-in self-test (pBIST) solutions help overcome this problem by offering the ability to adjust algorithms on-the-fly for silicon debug and incorporate these tests into production. We present a case-study where the flexibility of the pBIST engine has been exploited for debugging customer returned failures. The enhanced capability of our pBIST debug environment has allowed for a powerful array of post-silicon user-configurable memory test debug techniques that provide instant feedback. Through our debug process we have discovered the critical need for tests to access embedded memories in ways similar to functional access modes to isolate design sensitivities, process sensitivities, and even new defect types.