Surface Activated Prebonding in Local Laser Bonding of Silicon and Glass

Local laser bonding is an important technique to alleviate the high temperature adverse effect in silicon -glass bonding process. High pressure is applied in conventional local laser bonding to contact the bonding pair intimately. However, some disadvantages still exist under pressure load. Because of the interface between glass cover and glass chip, focusing is difficult. And glass bonding chip and cover are easy to be fractured under the high pressure. Therefore, surface activated prebonding is presented as an alternative technique to maintain the intimate contact between bonding pair. In this work, special chemical solutions were used to generate hydrophilic bonding surfaces and the silicon-glass prebonding is accomplished at room temperature. The laser with a wavelength of 1064nm was used and its focus spot diameter was 500mum and the power is 70w. Without any external pressure, the prebonded pairs were bonded locally and the bonding strength reaches 6.3-6.8Mpa.