The System-On-Chip (SoC) revolution challenges both design and test engineers, especially in the area of power dissipation. Generally, a circuit or system consumes more power in test mode than in normal mode. This extra power consumption can give rise to severe hazards in circuit reliability or, in some cases, can provoke instant circuit damage. Moreover, it can create problems such as increased product cost, difficulty in performance verification, reduced autonomy of portable systems, and decrease of overall yield. Low power dissipation during test application is becoming increasingly important in today's VLSI systems design and is a major goal in the future development of VLSI design.

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Survey of low power testing of VLSI circuits

Modern electronics testing has a legacy of more than 40 years. The introduction of new technologies, especially nanometer technologies with 90nm or smaller geometry, has allowed the semiconductor industry to keep pace with the increased performance-capacity demands from consumers. As a result, semiconductor test costs have been growing steadily and typically amount to 40% of today's overall product cost. 

This book is a comprehensive guide to new VLSI Testing and Design-for-Testability techniques that will allow students, researchers, DFT practitioners, and VLSI designers to master quickly System-on-Chip Test architectures, for test debug and diagnosis of digital, memory, and analog/mixed-signal designs.

KEY FEATURES
* Emphasizes VLSI Test principles and Design for Testability architectures, with numerous illustrations/examples.
* Most up-to-date coverage available, including Fault Tolerance, Low-Power Testing, Defect and Error Tolerance, Network-on-Chip (NOC) Testing, Software-Based Self-Testing, FPGA Testing, MEMS Testing, and System-In-Package (SIP) Testing, which are not yet available in any testing book.
* Covers the entire spectrum of VLSI testing and DFT architectures, from digital and analog, to memory circuits, and fault diagnosis and self-repair from digital to memory circuits.
* Discusses future nanotechnology test trends and challenges facing the nanometer design era; promising nanotechnology test techniques, including Quantum-Dots, Cellular Automata, Carbon-Nanotubes, and Hybrid Semiconductor/Nanowire/Molecular Computing.
* Practical problems at the end of each chapter for students.

System-on-Chip Test Architectures: Nanometer Design for Testability

This paper presents a new test-data compression technique that uses exactly nine codewords. Our technique aims at precomputed data of intellectual property cores in system-on-chips and does not require any structural information of cores. The technique is flexible in utilizing both fixed- and variable-length blocks. In spite of its simplicity, it provides significant reduction in test-data volume and test-application time. The decompression logic is very small and can be implemented fully independent of the precomputed test-data set. Our technique is flexible and can be efficiently adopted for single- or multiple-scan chain designs. Experimental results for ISCAS'89 benchmarks illustrate the flexibility and efficiency of the proposed technique.

Nine-coded compression technique for testing embedded cores in SoCs

We present a selective encoding method that reduces test data volume and test application time for scan testing of intellectual property (IP) cores. This method encodes the slices of test data that are fed to the scan chains in every clock cycle. Unlike many prior methods, the proposed method does not encode all the specified (0s and 1s) and unspecified (don't-care) bits in a slice. For example, if a slice contains more 1s than 0s, only the 0s are encoded and all don't-cares are mapped to 1. We use only c tester channels, where c = [log2(N + 1)] + 2, to drive N scan chains. In the best case, we can achieve compression by a factor of N/c using only one tester clock cycle per slice. We derive an upper bound on the density of care bits (either 1s or 0s) that allows us to achieve the best-case compression. The pattern decompression is of the continuous-flow type because no complex handshakes are required between the tester and the chip. Unlike popular compression methods such as EDT and SmartBIST, the proposed approach is suitable for IP cores because it does not require structural information for fault simulation, dynamic compaction, or interleaved test generation. The on-chip decoder is small, independent of the circuit under test and the test set, and it can be shared between different circuits. We present compression results for a number of industrial circuits, and compare our results to other recent compression methods targeted at IP cores. We show that up to 28times reduction in test data volume and 20times reduction in testing time is obtained for these circuits

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Test data compression for IP embedded cores using selective encoding of scan slices

Scan architectures, though widely used in modern designs, are expensive in power consumption. In this paper, we discuss the issues of excessive peak power consumption during scan testing. We show that taking care of high current levels during the test cycle (i.e. between launch and capture) is highly relevant to avoid noise phenomena such as IR-drop or ground bounce. We propose a solution based on power-aware assignment of don't care bits in deterministic test patterns. For ISCAS'89 and ITC'99 benchmark circuits, this approach reduces peak power during the test cycle up to 89% compared to a random filling solution

/pdf/minimizing-peak-power-consumption-during-scan-testing-test-4f13r8qlcv.pdf

Minimizing peak power consumption during scan testing: test pattern modification with X filling heuristics

It is common to use ATPG of scan-based design for high fault coverage in LSI testing. However, significant increase in test cost is caused in accordance with increasing design complexity. Recent strategies for test cost reduction combine ATPG and BIST techniques. Unfortunately, these strategies have serious constraints. We propose a new method that employs ATE and BIST structures to apply coded test patterns to LSI circuits. Results obtained using practical circuits show drastic test cost reduction capability of the proposed method.

http://ieeexplore.ieee.org/iel5/8533/26948/01197675.pdf

T. Mochiyama

Papers

BIST-aided scan test - a new method for test cost reduction