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Nondestructive Chemical Removal of Encapsulants used in Semiconductor Packaging

IP.com Disclosure Number: IPCOM000052120D
Original Publication Date: 1981-May-01
Included in the Prior Art Database: 2005-Feb-11
Document File: 1 page(s) / 12K

Publishing Venue

IBM

Related People

Clark, RJ: AUTHOR [+2]

Abstract

A composition and method for removing silicone oils, greases, gels or organic epoxies is described.

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This is the abbreviated version, containing approximately 92% of the total text.

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Nondestructive Chemical Removal of Encapsulants used in Semiconductor Packaging

A composition and method for removing silicone oils, greases, gels or organic epoxies is described.

In certain configurations of semiconductor chip packages organic epoxies, such as SCOTCHCAST* 5239 are used for edge sealing, and silicone gels, such as SYLGARDT* are used as top seals. Often it is necessary to remove these materials to rework the chip or substrate. The removal must be accomplished without damage to the components of the chip and packaging material. Unfortunately, many solvents for epoxies and silicone materials also damage polyimide materials which are used in the manufacture of the module assemblies.

It has been found that a solvent having about 95% by volume n-butylamine and about 5% by volume of oleic acid is an excellent solvent for silicone oils, greases and gels, especially SYLGARD, and also for organic epoxies, especially SCOTCHCAST 5239, and will not damage polyimide resins or other components of a silicon semiconductor package.

A preferred method of using the solvent is to place the solvent in a reflux system heated to about 78 degrees C and immerse the module in the solvent for about 1 to 3 hours. The module is then cooled in the reflux system to about room temperature. This will essentially remove all the silicone and epoxy material.

Following the solvent treatment, the modules are immersed in toluene for about 5 minutes and thereafter in isopropanol for abo...