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Browse Prior Art Database

High Productivity Multi-application Memory Chips

IP.com Disclosure Number: IPCOM000121726D
Original Publication Date: 1991-Sep-01
Included in the Prior Art Database: 2005-Apr-03
Document File: 2 page(s) / 71K

Publishing Venue

IBM

Related People

Furman, A: AUTHOR [+4]

Abstract

Through architectural means, a way is described for recovering semiconductor chips that have defects not covered by redundancy.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 52% of the total text.

High Productivity Multi-application Memory Chips

      Through architectural means, a way is described for
recovering semiconductor chips that have defects not covered by
redundancy.

      Increased chip densities of random-access memory chips, and
complex manufacturing processes, make the occurrences of random
manufacturing defects increasingly more likely. Through the use of
redundant circuits and multiple application features, a method is
provided for making these chips less sensitive to random
manufacturing defects. Through multiple application capability and
redundant circuits, greater productivity is realized than if any of
the applications had been implemented on separate chips with unique
application functions.

      Analysis of manufacturing yields of chips with multiple
application features shows that such chips are more productive than
chips with single features. For example, a 1-Mbit by 18 (18-Mbit)
chip can be used as a 2-Mbit by 9 chip. If a defective bit cannot
be fixed with redundancy, this chip can also function as a 16-Mbit
chip. The 16-Mbit applications can be as 16-Mbit by 1, 8-Mbit by 2,
4-Mbit by 4, 2-Mbit by 8 and 1-Mbit by 16. However, the techniques
described are not unique to this specific embodiment and can readily
be extended to any size chip like a 4-Mbit by 18 (72-Mbit chip)
functioning as a 64-Mbit chip, or a 16-Mbit by 18 functioning as a
256-Mbit chip, etc.

      The multifunction chips described consist of four quadrants.
Each quadrant contains its own redundant word and bit lines. When a
quadrant is add...