Protocol-aware ATE: Complement or competitor for structural testing?

Functional testing in production has been an enticing approach for many years because it is intuitively the way a function should be tested to ensure highest quality. For complex ICs, the tester hardware complexity, poor fault coverage, and lack of diagnosability of functional testing have led to its use primarily for design validation and characterization, and, in some cases, as a top-up test applied after all other tests. This in turn has reduced the need for these testers (reportedly this may account for ATE sales decreasing to 3% from 5% of silicon investment).