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Microprocessor Based Method for Manufacturing, Testing and Real-time Repairing of Embedded Memory

IP.com Disclosure Number: IPCOM000125666D
Publication Date: 2005-Jun-10
Document File: 3 page(s) / 762K

Publishing Venue

The IP.com Prior Art Database

Related People

Matthew Liong: AUTHOR [+2]

Abstract

At traditional manufacturing test time, a memory tester is used to test the memory, calculate any failed locations and generate the pattern for laser repair. In another approach, an embedded memory will have ECC capability, where the memory fault would be corrected automatically. The former approach would require extra testing cost, while the latter incurs extra silicon area cost. In this paper, a methodology is presented to avoid programming the tester, which costs more than programming an embedded CPU, in terms of programming development and manufacturing test.

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Microprocessor Based Method for Manufacturing, Testing and Real-time Repairing of Embedded Memory

Matthew Liong

, TM Liu

ABSTRACT

At traditional manufacturing test time, a memory tester is used to test the memory, calculate any failed locations and generate the pattern for laser repair.  In another approach, an embedded memory will have ECC capa

b

ility, where the memory fault would

b

e corrected automatically.  The former approach would require extra testing cost, while the latter incurs extra silicon area cost.  In this paper, a methodology is presented to avoid programming the tester, which costs more than programming an embedded CPU, in terms of programming development and manufacturing test.

Introduction

Traditionally, there are two ways to repair em

b

edded memory.

1.      Laser repair

The memory interface is muxed to the chip

b

oundary or the chip is equipped with BIST logic.  The tester tests the memory directly or initiates the BIST logic.  The tester should analyze the result and generate a fuse map for laser repair.

2.      ECC

The memory is em

b

edded with ECC logic and no external repair action is required.

Both of these methods will incur different kinds of operating cost, the manufacturing cost or the silicon cost.  The first method requires additional laser repair station setup.  The second method requires extra ECC logic.  The first method also requires the tester to execute an algorithm to prepare a fuse map for the laser repair.  This requires sophisticated programming skill of a tester, which is different from popular programming languages.  The development cost of the tester programming is much higher than PC programming, due to the high tester cost and programming unpopularity.

Self test and repair using on c...