Jedrzej Solecki

Low power programmable PRPG with enhanced fault coverage gradient

This paper describes a low power programmable generator capable of producing pseudorandom test patterns with desired toggling levels and enhanced fault coverage gradient compared to best-to-date BIST-based PRPGs. We introduce a method to automatically select several controls of the generator allowing easy and precise tuning. The same technique is subsequently employed to deterministically guide the generator toward test sequences with improved fault-coverage-to-pattern-count ratios. Experimental results obtained for industrial designs illustrate feasibility of the proposed test scheme and are reported herein.

Low-Power Programmable PRPG With Test Compression Capabilities

This paper describes a low-power (LP) programmable generator capable of producing pseudorandom test patterns with desired toggling levels and enhanced fault coverage gradient compared with the best-to-date built-in self-test (BIST)-based pseudorandom test pattern generators. It is comprised of a linear finite state machine (a linear feedback shift register or a ring generator) driving an appropriate phase shifter, and it comes with a number of features allowing this device to produce binary sequences with preselected toggling (PRESTO) activity. We introduce a method to automatically select several controls of the generator offering easy and precise tuning. The same technique is subsequently employed to deterministically guide the generator toward test sequences with improved fault-coverage-to-pattern-count ratios. Furthermore, this paper proposes an LP test compression method that allows shaping the test power envelope in a fully predictable, accurate, and flexible fashion by adapting the PRESTO-based logic BIST (LBIST) infrastructure. The proposed hybrid scheme efficiently combines test compression with LBIST, where both techniques can work synergistically to deliver high quality tests. Experimental results obtained for industrial designs illustrate the feasibility of the proposed test schemes and are reported herein.

Fault Diagnosis with Orthogonal Compactors in Scan-Based Designs

This paper presents a novel scheme to address the challenge of identifying failing scan cells from production test responses in the presence of scan compression. The scheme is based on a very simple test response compactor employing orthogonal—spatial and time—signatures. The advantage of this scheme as compared to previous work in this field is the simple and incremental nature of the compaction hardware required. The ability of the scheme to accurately identify failing scan cells from compacted responses has been measured on production fail data from five industrial designs and is reported herein.

Diagnosis of failing scan cells through orthogonal response compaction

This paper presents a novel scheme to address the challenge of identifying failing scan cells from production test responses in the presence of scan compression. The scheme is based on a very simple test response compactor employing orthogonal -- spatial and time -- signatures. The advantage of this scheme as compared to previous work in this field is the simple and incremental nature of the compaction hardware required. The ability of the scheme to accurately identify failing scan cells from compacted responses has been measured on production fail data from five industrial designs and is reported herein.

Trimodal Scan-Based Test Paradigm

This paper presents a novel scan-based design for test (DFT) paradigm. Compared with conventional scan, the presented approach either significantly reduces test application time while preserving high fault coverage or allows applying a much larger number of vectors within the same time interval. An equally important factor is the toggling activity during test—with this scheme, it remains similar to that of the mission mode. Several techniques are introduced that allow integration of the proposed scheme with the state-of-the-art test generation and application methods. In particular, the new scheme uses redesigned scan cells to dynamically configure scan chains into different modes of operation for use with the underlying test-per-clock principle. The experimental results obtained for large and complex industrial application-specific IC designs illustrate the feasibility of the proposed test scheme despite additional costs and efforts entailed in consolidating architectural changes and operations across a DFT flow.

A deterministic BIST scheme based on EDT-compressed test patterns

The paper presents a novel deterministic built-in self-test (BIST) scheme. The proposed solution seamlessly integrates with on-chip EDT-based decompression logic and takes advantage of two key observations: (1) specified positions of ATPG-produced test cubes are typically clustered within a single or a few scan chains for a small number of successive scan shift cycles, (2) only a small fraction of the specified positions are necessary to detect a fault, and most of the remaining ones have several alternatives that can be obtained by inverting preselected scan slices (all scan cells within a given cycle). The proposed approach elevates compression ratios to values typically unachievable through conventional reseeding-based solutions. Experimental results obtained for large industrial designs illustrate feasibility of the proposed logic BIST scheme and are reported herein.

TestExpress - New Time-Effective Scan-Based Deterministic Test Paradigm

This paper presents a novel scan-based DFT paradigm. Compared to conventional scan, the presented approach either significantly reduces test application time while preserving high fault coverage, or allows applying much larger number of vectors within the same time interval. An equally important factor is the power dissipated during test - with the new scheme it remains similar to that of the mission mode. Several techniques are introduced that allow easy integration of the proposed scheme with the state-of-the-art test generation and application methods. In particular, the new scheme uses redesigned scan cells to dynamically configure scan chains into different modes of operation for use with the underlying test-per-clock principle. Experimental results obtained for large and complex industrial ASIC designs illustrate feasibility of the proposed test schemes and are reported herein.

Star-EDT: Deterministic On-Chip Scheme Using Compressed Test Patterns

This paper presents Star-EDT—a novel deterministic test compression scheme. The proposed solution seamlessly integrates with EDT-based compression and takes advantage of two key observations: 1) there exist clusters of test vectors that can detect many random-resistant faults with a cluster comprising a parent pattern and its derivatives obtained through simple transformations and 2) a significant majority of specified positions of ATPG-produced test cubes are typically clustered within a single or, at most, a few scan chains. The Star-EDT approach elevates compression ratios to values typically unachievable through conventional reseeding-based solutions. Experimental results obtained for large industrial designs, including those with a new class of test points aware of ATPG-induced conflicts, illustrate feasibility of the proposed deterministic test scheme and are reported herein. In particular, they confirm that the Star-EDT can act as a valuable form of deterministic BIST.