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Browse Prior Art Database

Replacing Defective Lines

IP.com Disclosure Number: IPCOM000093475D
Original Publication Date: 1967-Oct-01
Included in the Prior Art Database: 2005-Mar-06
Document File: 2 page(s) / 44K

Publishing Venue

IBM

Related People

Archey, WB: AUTHOR [+2]

Abstract

Defective lines in circuits are replaced with extra lines provided for this purpose. The method comprises blowing a fusing resistor to disconnect the defective line, then blowing other fusing resistors to connect an extra line in its place. The method is particularly useful for disconnecting defective bit sense lines in a magnetic array and substituting extra lines provided for this purpose.

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Replacing Defective Lines

Defective lines in circuits are replaced with extra lines provided for this purpose. The method comprises blowing a fusing resistor to disconnect the defective line, then blowing other fusing resistors to connect an extra line in its place. The method is particularly useful for disconnecting defective bit sense lines in a magnetic array and substituting extra lines provided for this purpose.

Four lines A, B, C, and D, and an extra line R, are to be connected to four terminals. It is assumed that line B is defective.

The first step in the method is to ground line B and drive a current I into the B terminal through the fuse RB and to ground until RB opens. The next step is to disconnect line R from each of the good lines A, C, and D by grounding line R and driving current into each good line until fuses R1, R3, and R4 open. Line R is now connected to terminal B, bad line B is disconnected, and good lines A, C, and D are connected to terminals A, C, and D respectively.

There are requirements of the fusing resistors. First, they must have a low resistance relative to load resistances. Second, they must meet power requirements in the operating device, but be blown with less current than would harm the device. Third, they must have no serious reliability of process difficulties. These requirements are satisfied by chromium fusing resistors which can be incorporated into thin-film circuits by conventional photoresist and etching processes.

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