Comparing functional and structural tests

This paper describes an experimental study to understand issues and requirements for structural-based testing using low cost testers, compared to functional-based testing using expensive testers. Several studies have been directed at the effectiveness of various test methods, but none explicitly addressed issues involved in attempting to replace functional vectors with scan vectors and none carried the experiment further by placing defective chips into systems and running system tests. This paper describes the results of such an experiment and offers insight into necessary requirements for reduction or elimination of functional tests.