Void-free full wafer adhesive bonding

In this paper we present guidelines for void free adhesive bonding of 10 cm diameter wafers. We have systematically investigated the influence of different bonding parameters on void formation in the bond. The layer thicknesses of the tested polymer coatings are between 1 /spl mu/m and 12 /spl mu/m. The polymer material, the bonding pressure and the pre-curing time and temperature for the polymer has shown significant influence on void formation in the bond. High bonding pressure and pre-curing times/temperatures that are specific to the polymer material counteract void formation. Process parameters for achieving void-free bonds using benzocyclobutene (BCB) and photoresist coatings as adhesive materials are given. Excellent bonding results have been achieved with BCB as bonding material.