Optimization of cell-aware ATPG results by manipulating library cells' defect detection matrices

Zhan Gao, Min Chun Hu, Joe Swenton, Santosh Malagi, Jos Huisken, Kees Goossens, Erik Jan Marinissen

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Abstract

Cell-aware test (CAT) explicitly targets defects inside library cells and therefore significantly reduces the number of test escapes compared to conventional automatic test pattern generation (ATPG) approaches that cover cell-internal defects only serendipitously. CAT consists of two steps, viz. (1) library characterization and (2) cell-aware ATPG. Defect detection matrices (DDMs) are used as the interface between both CAT steps; they record which cell-internal defects are detected by which cell-level test patterns. This paper proposes two algorithms that manipulate DDMs to optimize cell-aware ATPG results with respect to fault coverage, test pattern count, and compute time. Algorithm 1 identifies don't-care bits in cell patterns, such that the ATPG tool can exploit these during cell-to-chip expansion to increase fault coverage and reduce test-pattern count. Algorithm 2 selects, at cell level, a subset of preferential patterns that jointly provides maximal fault coverage at a minimized stimulus care-bit sum. To keep the ATPG compute time under control, we run cell-aware ATPG with the preferential patterns first, and a second ATPG run with the remaining patterns only if necessary. Selecting the preferential patterns maps onto a well-known N Phard problem, for which we derive an innovative heuristic that outperforms solutions in the literature. Experimental results on twelve circuits show average reductions of 43% of non-covered faults and 10% in chip-pattern count.

Original languageEnglish
Title of host publicationProceedings - 2019 IEEE International Test Conference in Asia, ITC-Asia 2019
Place of PublicationPiscataway
PublisherInstitute of Electrical and Electronics Engineers
Pages91-96
Number of pages6
ISBN (Electronic)978-1-7281-4718-5
DOIs
Publication statusPublished - 1 Sep 2019
Event3rd IEEE International Test Conference in Asia, ITC-Asia 2019 - Tokyo, Japan
Duration: 3 Sep 20195 Sep 2019

Conference

Conference3rd IEEE International Test Conference in Asia, ITC-Asia 2019
CountryJapan
CityTokyo
Period3/09/195/09/19

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Keywords

  • ATPG
  • Cell Aware
  • DDM
  • Don't Care
  • MinCover

Cite this

Gao, Z., Hu, M. C., Swenton, J., Malagi, S., Huisken, J., Goossens, K., & Marinissen, E. J. (2019). Optimization of cell-aware ATPG results by manipulating library cells' defect detection matrices. In Proceedings - 2019 IEEE International Test Conference in Asia, ITC-Asia 2019 (pp. 91-96). [8871851] Piscataway: Institute of Electrical and Electronics Engineers. https://doi.org/10.1109/ITC-Asia.2019.00029