Development of alumina green sheet for tight dimensional tolerance LSI packages

Acrylic resin was selected and its functional group and monomer optimized to develop alumina green sheet for tight-dimensional-tolerance LSI packages. The carboxyl group was found to be the most suitable functional group for obtaining a well-dispersed slurry and high stable green sheet density for alumina powder. A polymerized acrylic resin was found to be given the best pyrolysis behavior. The fired shrinkage of the thin green sheet (0.5 mm) and the laminated thick green sheet (5.0 mm) were the same when this resin was used. The green sheet using this acrylic resin polymerized with a small amount of carboxyl functional group shows stable, fired shrinkage that is largely independent of raw material lots, tape casting lots, and green sheet thickness. As a result, fluctuation of the fired shrinkage is within ±0.1%. Pin grid arrays with 400 pins and 100-mil pitch per 4-mil line pitch can be produced by this green sheet, which is acceptable for tight dimensional tolerances