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

Advances in semiconductor process and design technology enable the design of complex system chips. Traditional IC design in which every circuit is designed from scratch and reuse is limited to standard-cell libraries, is more and more replaced by a design style based on embedding large reusable modules, the so-called cores. This core-based design poses a series of new challenges, especially in the domains of manufacturing test and design validation and debug. This paper provides an overview of current industrial practices as well as academic research in these areas. We also discuss industry-wide efforts by VSIA and IEEE P1500 and describe the challenges for future research.

Testing embedded-core based system chips

Test access mechanisms (TAMs) and test wrappers are integral parts of a system-on-chip (SoC) test architecture. Prior research has concentrated on only one aspect of the TAM/wrapper design problem at a time, i.e., either optimizing the TAMs for a set of pre-designed wrappers, or optimizing the wrapper for a given TAM width. In this paper, we address a more general problem, that of carrying out TAM design and wrapper optimization in conjunction. We present an efficient algorithm to construct wrappers that reduce the testing time for cores. Our wrapper design algorithm improves on earlier approaches by also reducing the TAM width required to achieve these lower testing times. We present new mathematical models for TAM optimization that use the core testing time values calculated by our wrapper design algorithm. We further present a new enumerative method for TAM optimization that reduces execution time significantly when the number of TAMs being designed is small. Experimental results are presented for an academic SoC as well as an industrial SoC.

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Test wrapper and test access mechanism co-optimization for system-on-chip

Recently, designers have been embedding reusable modules to build on-chip systems that form rich libraries of predesigned, preverified building blocks. These embedded cores make it easier to import technology to a new system and differentiate the corresponding product by leveraging intellectual property advantages. Most importantly, design reuse shortens the time-to-market for new systems. The attributes that make system chips built with embedded IP cores an attractive methodology-design reuse, heterogeneity, reconfigurability, and customizability-also make testing and debugging these chips a complex challenge. The authors review the various alternatives for testing embedded cores and describe solutions and proposed standards that are expected to play a key role in developing the core based design paradigm.

Testing embedded-core-based system chips

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

The main objective of core-based IC design is improvement of design efficiency and time-to-market. In order to prevent test development from becoming the bottleneck in the entire development trajectory, reuse of pre-computed tests for the reusable pre-designed cores is mandatory. The core user is responsible for translating the test at core level into a test at chip level. A standardized test access mechanism eases this task, therefore contributing to the plug-n-play character of core-based design. This paper presents the concept of a structured test access mechanism for embedded cores. Reusable IP modules are wrapped in a TESTSHELL. Test data access from chip pins to TESTSHELL and vice versa is provided by the TESTRAIL, while the operation of the TESTSHELL is controlled by a dedicated test control mechanism (TCM). Both TESTRAIL as well as TCM are standardized, but open for extensions.

R. Arendsen

Papers

A structured and scalable mechanism for test access to embedded reusable cores