Generating test sets for diagnosing scan chain failures

摘要

Embodiments of the disclosed technology comprise software-based techniques that can be used to improve scan chain test pattern generation and scan chain failure diagnosis resolution. For example, certain embodiments can be used to generate high quality chain diagnosis test patterns that are able to isolate a scan chain defect to a single scan cell. Such embodiments can be used to generate a “complete” test set—that is, a set of chain diagnosis test patterns that is able to isolate any scan chain defect in a faulty scan chain to a single scan cell.

主权项

1. One or more computer-readable storage media storing computer-executable instructions for causing a computer to perform a method, the method comprising:
performing a first test pattern generation technique targeting a fault caused by a possible defect at a scan cell N of a scan chain, the first test pattern generation technique being designed to generate a single test pattern for detecting the fault at the scan cell N; and performing a second test pattern generation technique targeting the fault if the first test pattern generation technique fails to generate the single test pattern, the second test pattern generation technique being designed to generate a plurality of test patterns that can be collectively used to differentiate the fault at the scan cell N from a fault at scan cell N−1 and its downstream scan cells.