Browse Prior Art Database

Large Scale Integrated Circuit Module Repair

IP.com Disclosure Number: IPCOM000078712D
Original Publication Date: 1973-Feb-01
Included in the Prior Art Database: 2005-Feb-26
Document File: 2 page(s) / 24K

Publishing Venue

IBM

Related People

Agnihotri, RK: AUTHOR [+2]

Abstract

Polyimide coating encapsulants often provide better protection for metallized ceramic modules from corrosive and hostile environments in contrast to silicones. This process provides a method for reworking multichip large-scale integrated circuit modules.

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Large Scale Integrated Circuit Module Repair

Polyimide coating encapsulants often provide better protection for metallized ceramic modules from corrosive and hostile environments in contrast to silicones. This process provides a method for reworking multichip large-scale integrated circuit modules.

Firstly, the initial chip is suitably encapsulated at 10 with the appropriate polyimide. After testing, defective chips are identified and marked for removal. At each of the defective chip locations, a drop of hydrazine hydrate is deposited. After about ten minutes, the chip is rinsed with a diluted solution of HCl. This step 12 removes the polyimide encapsulation from the top and sides of the chip. Thereafter, localized heat, such as infrared radiation or a heating gun, is employed to melt the solder connection between the chip and substrate so as to facilitate chip removal and replacement at 14. Conventional techniques are then employed to rebond a substitute chip in place of the defective chip and, thereafter, the exposed areas are recoated with a polyimide encapsulant at 16.

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