Solvent Resistance of Silicones used for Electronic Packaging Applications

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Michelle Velderrain, Technical Specialist
Scott Duffer, Quality Assurance Technician
Bill Riegler, Product Director-Engineering Materials
NuSil Technology LLC
1050 Cindy Lane
 Carpinteria, CA 93013
(805) 684-8780, fax (805) 566-9905, michelle@nusil.com

Presented as a poster presentation at International Microelectronics and Packaging Society (IMAPS) Conference, October 9-13, 2006, San Diego, CA., U.S.A

Abstract

Silicones are becoming more popular in advanced packaging for their thermal stability above 200oC and ability to protect the electronic package from environmental factors.  The electronic package may be exposed to a variety of different solvents by fabricators in the cleaning process.  Problems arise when the silicone swells with solvent. When the solvent evaporates, the silicone will become harder and put stress on the metal bonds, potentially bending and even shearing them.  Fundamentals of silicone manufacturing allow silicones to have different chemical characteristics that can respond differently to various solvents. For example, some silicones are more resistant to hydrocarbon solvents, whereas others are more resistant to halogenated solvents.  The purpose of this study is to evaluate the solvent resistance of silicone materials that can be used for electronic packaging.  The solvents chosen for this study are commonly used solvents used in the electronics industry and the silicone materials chosen were based on the chemical composition. The change in thickness and specific gravity (% Swell) was measured over time after silicone was exposed to various solvents. By understanding how the electronic package is affected by different solvents, the appropriate solvent and silicone system can be chosen.

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