Fault diagnosis in scan-based BIST using both time and space information

Abstract

A new technique for diagnosis in a scan-based BIST environment is presented.i t allows non-adaptive identijkation of both the scan cells that capture errors (space information) as well as a subset of the failing test vectors (time information). Having both space and time information allows a faster and more precise diagnosis. Previous techniques for identifying the failing test vectors during BIST have been limited in the multiplicity of errors that can be handled andlor require a very large hardware overhead. The proposed approach, however, uses only two cycling registers at the output of the scan chain to accurately identify a subset of the failing BIST test vectors. This is accomplished using some novel pruning techniques that efficiently extract information ffom the signatures of the cycling registers. While not all the failing BIST test vectors can be ident$ed, results indicate that a significant number of them can be. This additional information can save a lot of time in failure analysis. r

Fault Diagnosis with Orthogonal Compactors in Scan-Based Designs

“…For instance, a hybrid compactor of [9] combined with a pruning technique has such an ability. A scheme based on Reed-Solomon codes and a programmable MISR [33] collects signatures during BIST sessions, repeated for each feedback polynomial.…”

An interval-based diagnosis scheme for identifying failing vectors in a scan-BIST environment

“…A direct comparison with related prior work [13] is difficult since we are using different test vector sets in this work. Moreover, the goal of [13] was to obtain a small (incomplete) set of true failing vectors.…”

“…Moreover, the goal of [13] was to obtain a small (incomplete) set of true failing vectors. Here, the primary objective is to retain all failing vectors in the candidate set.…”

“…These techniques suffer from the drawback of limitations on error multiplicity [8], diagnostic aliasing [9,10,11], and high overhead [10,12]. Recently, a method based on the combination of cycling registers and pruning techniques was proposed for failing vector identification [13]. While this approach is useful in narrowing down the set of candidate failing vectors, it suffers from the drawback that it does not identify all the failing vectors.…”

Diagnosis for scan-based BIST: reaching deep into the signatures

“…An alternative approach targets the identification of scan cells that capture incorrect information during test [9,6,3,2]. A limited set of efforts attacks both problems simultaneously, most notably [5].…”