Glass direct bonding technology for hermetic seal package

A new SMD type hermetic seal package using glass wafers has been developed for SAW (Surface Acoustic Wave) resonators. This package is composed of two glass wafers in which many cavities and through holes are formed. The SAW resonator chip is inserted into the cavity. Electrodes are led out from the through holes without using wire. Two glass wafers are directly bonded at the atomic level using no adhesive. This package technology realizes small size, low profile SMD type package whose size is the chip size plus 1.0 mm and whose height is 1.0 mm. The size of the glass package type SAW resonator is 4.0 x 2.0 x 1.0 mm. The area is 1/9 and the volume is 1/33 of the conventional CAN package. The frequency characteristics and reliability of the developed SAW resonators were checked. No degradation was observed by the packaging process. The insertion loss was reduced by wireless assembly. The change in the characteristics after high-temperature storage test was extremely small because no resin is used in the glass package.