SOL-GEL PROCESSING IN ELECTRONIC PACKAGING MATERIALS

Published works on sol-gel processes in the field of electronic packaging materials are critically reviewed. A novel application of the sol-gel process for the fabrication of low coefficient of thermal expansion (CTE) polymer matrix composite laminates has been described. The approach consists of the impregnation of glass yarns or fabrics with silica-based sol derived from metal alkoxides. After firing at approximately 400-degrees-C, the sol-gel coatings restrict the movement of glass fibers within the yarn/fabric leading to the lowering of CTE. The sol-gel treated fabrics are subsequently impregnated with a polymer resin and laminated to single layer or multilayer laminates. In addition, the sol-gel treated fabrics were used to produce low CTE copper composite layers (to be used as a restrainer) by the plating of copper onto the gel-treated glass fabrics. Results show that the laminates produced with sol-gel treated fabrics gave CTE values lower than those obtained from the fabrics without sol-gel treatments.