Method of localized and low-temperature wafer bonding for micro-system packaging

This paper presents a novel approach for bonding technique based on the concept of patternable and low temperature process. This method especially is suitable for the design of microstructure by surface micromachining. By this way, the bonding can be solved. The patternable intermediate of photoresist is applied to conduct wafer-bonding experiment. SU-8 is selected as intermediate layer the thickness of SU-8 not only can be easily controlled, but also can be patterned into any-shape by the technique. Furthermore, this method provides smooth intermediate pad to contact for bonding. The experiment of wafer-to-water intermediate bonding was conducted. The preliminary results show that the influences of high temperature, electric field, and void can be avoided. The tensile stress test is shown the bonding strength up to 216 kg/cm(2) can be reached.