Distribution-Controlled X-Identification for Effective Reduction of Launch-Induced IR-Drop in At-Speed Scan Testing

Kohei MIYASE  Kenji NODA  Hideaki ITO  Kazumi HATAYAMA  Takashi AIKYO  Yuta YAMATO  Hiroshi FURUKAWA  Xiaoqing WEN  Seiji KAJIHARA  

IEICE TRANSACTIONS on Information and Systems   Vol.E94-D   No.6   pp.1216-1226
Publication Date: 2011/06/01
Online ISSN: 1745-1361
DOI: 10.1587/transinf.E94.D.1216
Print ISSN: 0916-8532
Type of Manuscript: PAPER
Category: Dependable Computing
ATPG,  X-bit,  X-identification,  X-filling,  

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Test data modification based on test relaxation and X-filling is the preferred approach for reducing excessive IR-drop in at-speed scan testing to avoid test-induced yield loss. However, none of the existing test relaxation methods can control the distribution of identified don't care bits (X-bits), thus adversely affecting the effectiveness of IR-drop reduction. In this paper, we propose a novel test relaxation method, called Distribution-Controlled X-Identification (DC-XID), which controls the distribution of X-bits identified in a set of fully-specified test vectors for the purpose of effectively reducing IR-drop. Experiments on large industrial circuits demonstrate the effectiveness and practicality of the proposed method in reducing IR-drop, without lowering fault coverage, increasing test data volume and circuit size.