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Wafer Basic System Module Concept

IP.com Disclosure Number: IPCOM000080723D
Original Publication Date: 1974-Feb-01
Included in the Prior Art Database: 2005-Feb-27
Document File: 1 page(s) / 12K

Publishing Venue

IBM

Related People

Vajda, AM: AUTHOR

Abstract

Described is a very flexible, user transparent, approach for creating a basic system module organized to avoid bad bits in the integrated circuit memories units, which comprise the basic system module. The system yields maximum utilization of the bits in the memories.

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Wafer Basic System Module Concept

Described is a very flexible, user transparent, approach for creating a basic system module organized to avoid bad bits in the integrated circuit memories units, which comprise the basic system module. The system yields maximum utilization of the bits in the memories.

These advantages are accomplished by organizing each integrated circuit memory unit into a main and auxiliary memory. Each bit in each integrated circuit memory unit is tested, and at this time each memory unit is organized on either a word or a bit dimension. This organization depends upon where the most significant bit of input addresses go and what the number and placement of defects are, i.e., what the greatest yield would be for the tested memory unit. Based on this, the maximum recoverable number of bits for each integrated circuit memory unit is determined, and the units are grouped in a decreasing order of quality.

Enough units of the highest quality are then chosen to produce the desired basic system module size, if all the chosen units are perfectly good. These chosen units are now designated as the main memory. Once the main memory size has been determined, the number of declared defective addresses in this main memory are determined, and additional units of lesser quality are chosen to be able to replace these defective addresses. This second group of units will serve as an auxiliary memory. Any defects in the units used in the auxiliary memory can simply be bypassed.

Each unit is then divided into blocks, which...