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

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review


Test data modification based on test relaxation and Xfilling 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.

Original languageEnglish
Pages (from-to)1216-1226
Number of pages11
JournalIEICE Transactions on Information and Systems
Issue number6
Publication statusPublished - 2011 Jun
Externally publishedYes


  • ATPG
  • X-bit
  • X-filling
  • X-identification

ASJC Scopus subject areas

  • Software
  • Hardware and Architecture
  • Computer Vision and Pattern Recognition
  • Electrical and Electronic Engineering
  • Artificial Intelligence


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