On Statistical Estimation of Fault Efficiency for Path Delay Faults Based on Untestable Path Analysis

Masayasu FUKUNAGA  Seiji KAJIHARA  Sadami TAKEOKA  

Publication
IEICE TRANSACTIONS on Information and Systems   Vol.E88-D   No.7   pp.1671-1677
Publication Date: 2005/07/01
Online ISSN: 
DOI: 10.1093/ietisy/e88-d.7.1671
Print ISSN: 0916-8532
Type of Manuscript: PAPER
Category: Dependable Computing
Keyword: 
path delay fault,  untestable path,  potentially testable path,  fault efficiency,  

Full Text: PDF(252.5KB)>>
Buy this Article




Summary: 
We propose a method to estimate fault efficiency of test patterns for path delay faults. In path delay fault testing, fault coverage of test patterns is usually very low, because circuits have not only a lot of paths but also a lot of untestable paths. Although fault efficiency would be better metric to evaluate test patterns rather than fault coverage, it is too difficult to compute it exactly, if we do not compute the total number of untestable paths exactly. The proposed method samples a part of paths after untestable path analysis, and estimate fault efficiency based on the percentage of untestable paths in the sample paths. Through our experimental results, we show that the proposed method can accurately estimate fault efficiency of test patterns in a reasonable time. Also, since the accuracy of fault efficiency estimated with the proposed method depends on how to sample the paths, we look into the influence of path sampling methods to the accuracy in the experiments.