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Incorporating the effect of delay variability in path based delay testing

Delay variability poses a formidable challenge in both design and test of nanometer
circuits. While process parameter variability is increasing with technology scaling, as circuits
are becoming more complex, the dynamic or vector dependent variability is also increasing
steadily. In this research, we develop solutions to incorporate the effect of delay variability
in delay testing. We focus on two different applications of delay testing.
In the first case, delay testing is used for testing the timing performance of a circuit
using path based fault models. We show that if dynamic delay variability is not accounted for
during the path selection phase, then it can result in targeting a wrong set of paths for test.
We have developed efficient techniques to model the effect of two different dynamic effects
namely multiple-input switching noise and coupling noise. The basic strategy to incorporate
the effect of dynamic delay variability is to estimate the maximum vector delay of a path
without being too pessimistic.
In the second case, the objective was to increase the defect coverage of reliability
defects in the presence of process variations. Such defects cause very small delay changes and hence can easily escape regular tests. We develop a circuit that facilitates accurate
control over the capture edge and thus enable faster than at-speed testing. We further
develop an efficient path selection algorithm that can select a path that detects the smallest
detectable defect at any node in the presence of process variations. / text

Identiferoai:union.ndltd.org:UTEXAS/oai:repositories.lib.utexas.edu:2152/6559
Date19 October 2009
CreatorsTayade, Rajeshwary G.
Source SetsUniversity of Texas
LanguageEnglish
Detected LanguageEnglish
Formatelectronic
RightsCopyright is held by the author. Presentation of this material on the Libraries' web site by University Libraries, The University of Texas at Austin was made possible under a limited license grant from the author who has retained all copyrights in the works.

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