This paper presents a novel test-data volume-compression methodology called the embedded deterministic test (EDT), which reduces manufacturing test cost by providing one to two orders of magnitude reduction in scan test data volume and scan test time. The presented scheme is widely applicable and easy to deploy because it is based on the standard scan/ATPG methodology and adopts a very simple flow. It is nonintrusive as it does not require any modifications to the core logic such as the insertion of test points or logic bounding unknown states. The EDT scheme consists of logic embedded on a chip and a new deterministic test-pattern generation technique. The main contributions of the paper are test-stimuli compression schemes that allow us to deliver test data to the on-chip continuous-flow decompressor. In particular, it can be done by repeating certain patterns at the rates, which are adjusted to the requirements of the test cubes. Experimental results show that for industrial circuits with test cubes with very low fill rates, ranging from 3% to 0.2%, these schemes result in compression ratios of 30 to 500 times. A comprehensive analysis of the encoding efficiency of the proposed compression schemes is also provided.

Embedded deterministic test

VLSI Test Principles and Architectures: Design for Testability (Systems on Silicon)

This paper introduces embedded deterministic test (EDT) technology, which reduces manufacturing test cost by providing one to two orders of magnitude reduction in scan test data volume and scan test time. The EDT architecture, the compression algorithm, design flow, experimental results, and silicon implementation are presented.

Embedded deterministic test for low cost manufacturing test

This book is a comprehensive guide to new DFT methods that will show the readers how to design a testable and quality product, drive down test cost, improve product quality and yield, and speed up time-to-market and time-to-volume.

· Most up-to-date coverage of design for testability. 
· Coverage of industry practices commonly found in commercial DFT tools but not discussed in other books. 
· Numerous, practical examples in each chapter illustrating basic VLSI test principles and DFT architectures.
· Lecture slides and exercise solutions for all chapters are now available.
· Instructors are also eligible for downloading PPT slide files and MSWORD solutions files from the manual website.

Table of Contents

Chapter 1 - Introduction
Chapter 2 - Design for Testability
Chapter 3 - Logic and Fault Simulation 
Chapter 4 - Test Generation 
Chapter 5 - Logic Built-In Self-Test
Chapter 6 - Test Compression
Chapter 7 - Logic Diagnosis
Chapter 8 - Memory Testing and Built-In Self-Test
Chapter 9 - Memory Diagnosis and Built-In Self-Repair
Chapter 10 - Boundary Scan and Core-Based Testing
Chapter 11 - Analog and Mixed-Signal Testing
Chapter 12 - Test Technology Trends in the Nanometer Age

VLSI Test Principles and Architectures: Design for Testability

SmartBIST is a name for a family of streaming scan test pattern decoders that are suitable for on-chip integration. The automatic test pattern generation (ATPG) algorithms are modified to generate scan test stimulus vectors in a highly compacted source format that is compatible with the SmartBIST decoder hardware. The compacted stimulus vectors are streamed from automatic test equipment (ATE) to the decoder, which expands the data stream in real-time into fully expanded scan test vectors. SmartBIST encoding and decoding use simple algebraic techniques similar to those used for LFSR-coding (also known as LFSR-reseeding). The specific SmartBIST implementation shown in this paper guarantees that all test cubes can be successfully encoded by the modified ATPG algorithm irrespective of the number and position of the care bits.

A SmartBIST variant with guaranteed encoding

Rapid increases in the wire-able gate counts of ASICs stress existing manufacturing test equipment in terms of test data volume and test capacity. Techniques are presented in this paper that allow for substantial compression of Automatic Test Pattern Generation (ATPG) produced test vectors. We show compression efficiencies allowing a more than 10-fold reduction in tester scan buffer data volume on ATPG compacted tests. In addition, we obtain almost a 2/spl times/ scan test time reduction. By implementing these techniques for production testing of huge-gate-count ASICs, IBM will continue using existing automated test equipment (ATE)-avoiding costly upgrades and replacements.

OPMISR: the foundation for compressed ATPG vectors

Rapidly increasing ASIC gate counts are stressing the test capacity of manufacturing test equipment. New on-product multiple-input signature register (OPMISR) techniques compress test vectors produced by ATPG, substantially reducing data volume and test time.

Extending OPMISR beyond 10/spl times/ scan test efficiency

A system for reducing test data volume in the testing of logic products such as modules on integrated circuit chips, and systems comprised of multiple integrated circuit chips. Test stimulus data are loaded from a tester into the logic product to apply to portions of combinational logic circuitry therein in order to detect faults comprises “care” bits and “non-care” bits. The care bits target focal faults of interest in the logic circuitry being tested while the non-care bits do not. Non-care bits in the test vector data are filled with repetitive, repeating, or other background data sequences. The background data sequences are constructed such that they can be algorithmically recovered from a small amount of initialization data. The recovery can use hardware that is located in the product under test, inside the tester, or between the product under test and the tester, or software residing in the tester and operating while the test is performed. The software and/or hardware recover the full test input stimulus data including the fill data from the much more compact source data. The use of a compacted data format for the fill data provides for a high degree of compressibility of the total test input stimulus vector data set. The method for test data reduction combines the compact data representation for the input stimulus data with on-product or off-product compression of the test response data. The response data compression can be accomplished by the use of error-detecting codes, by comparing the responses from several identical products under test. The combination of data compression techniques for both, test input stimulus data and test output response data, results in significantly better overall data reduction.

System for reducing test data volume in the testing of logic products

A method and system for repairing defective memory in a semiconductor chip. The chip has memory locations, redundant memory, and a central location for ordered fuses. The ordered fuses identify in compressed format defective sections of the memory locations. The defective sections are replaceable by sections of the redundant memory. The ordered fuses have an associated a fuse bit pattern of bits which sequentially represents the defective sections in the compressed format. The method and system determines the order in which the memory locations are wired together; designs a shift register of latches through the memory locations in accordance with the order in which the memory locations are wired together; and associates each of the latches with a corresponding bit of an uncompressed bit pattern from which the fuse bit pattern is derived. The uncompressed bit pattern comprises a sequence of bits, representing the defective sections in uncompressed format.

Automation of fuse compression for an asic design system

A method and system for generating a set of scan diagnostic patterns for diagnosing fails in scan chains. The method including: (a) selecting a set of latches; (b) selecting a pattern from a set of test patterns; (c) determining the number of lateral insertions of the selected pattern; (d) determining a number of new lateral insertions that the selected pattern would add to the set of scan diagnostic pattern and adding the selected pattern and a corresponding new insertion count to a count list; (e) repeating steps (b) through (d) until all patterns of the set of test patterns have been selected; (f) selecting a pattern from the count list; (g) adding the pattern selected from the count list to the set of scan diagnostic patterns; and (h) repeating steps (b) through (g) until a there are a predetermined number of patterns in the set of scan diagnostic patterns.

Frank O. Distler

Papers

OPMISR: the foundation for compressed ATPG vectors

Extending OPMISR beyond 10/spl times/ scan test efficiency

System for reducing test data volume in the testing of logic products

Automation of fuse compression for an asic design system

Method for optimizing a set of scan diagnostic patterns