AC-Scan: Microprocessors are ready ... But where is the Infrastructure?

Functional vectors have been used by many in the industry to apply tests at-speed with the hope of targeting delay faults. However, there are many barriers to the widespread adoption of functional test vectors as the mainstream mechanism to target delay faults. First and foremost, functional vector generation is a largely manual effort and the costs of generating functional tests for stuck-at faults, leave alone delay defects, are prohibitively high. Second, unlike the predictability offered by scan test vectors, functional test coverage is highly unpredictable. Third, in a highvolume manufacturing environment where test time and volume is paramount, functional vectors may not offer the same time and space efficiency as scan vectors. Fourth, fault grading functional vectors for delay faults (even for stuck faults) is generally a gargantuan task.