M.S. Thesis Presentation by Manjula N. Variyam
Tuesday, May 25, 1999

(Dr. Prateen V. Desai, advisor)

"Palletization and Design-of-Simulations for Large Area Processing and Assembly in Electronic Packaging"

Abstract

With the continued push toward low-cost fabrication, large-area processing of thin-film materials is being aggressively pursued by the electronic packaging industry.  The present work studies innovative materials, models, and processing techniques to facilitate large-area processing of alumina and silicon tiles.  As the alumina and silicon tiles are commercially available in smaller dimensions, a palletization approach has been developed to facilitate large-area processing.  In the palletization approach, alumina and silicon tiles are attached to re-usable glass pallets with a suitable adhesive.

Models incorporating the viscoelastic behavior of the adhesive material have been developed to understand the warpage and interfacial stresses induced during the palletization process and during the subsequent thin-film processing on the tiles.  The predictions from the models have been validated using data from in-situ shadow-moiré experiments, where measurements were taken during cooling from adhesive cure temperature and during assembly dwelling at room temperature.

Within the weight and height constraints imposed to implement multi-chip module (MCM) thin-film deposition processing, studies have been conducted to understand the role of, for example, tile/pallet thickness ratio, pallet coefficient of thermal expansion, and the adhesive modulus on the assembly behavior. The classical design-of-experiments methodology is extended here to apply to such a study with no replications.  Such a “design-of-simulations” (DOS) method along with the appropriate statistical analysis tools has been used to select a suitable adhesive. The proposed DOS methodology is extended to analyze process modeling of thin-films on large area substrates as well as flip-chip assemblies.  From adhesion studies conducted in a parallel research, it is seen that the adhesive will be able to withstand the stresses induced due to curing and thin-film processing without delaminating.