New packaging technology for SAW device

A new hermetic seal package using glass wafers for surface acoustic wave (SAW) device was developed. Two glass wafers are used. Cavity and through hole are formed on each glass wafer by the grinding process. Two glass wafers are combined in atomic level by using the glass direct bonding technique. The SAW device chip is inserted into the cavity. Electrodes are taken out from through holes by solder balls without using wires. These technologies were applied to SAW resonator. The size of developed SAW resonator is 4.0/spl times/2.0/spl times/0.8 mm. The characteristics and reliability of developed SAW resonator were investigated. The characteristics degradation by packaging process was not observed. Insertion loss was improved due to wireless assembly, and the characteristics change after high temperature preservation test was extremely small because there is no resin in the glass package.