We have developed a simple, low cost technique using new materials to bond capacitance pressure sensors. The old methods have difficult processes when a metal trace on the bonding area perturbs the sealing. The new method uses a polymeric gap-controlling block between glass and silicon wafers and a heat curing adhesive which penetrates between them due to capillary force. We used two different materials including SU-8™ and UV (ultraviolet) curing adhesive in order to control the gap. The technique allows us to generate a small gap between the chips due to low viscosity of the heat curing adhesive, align and bond chips immediately, make a strong bond, and easily seal the sensor. Also, the high temperature, strong heat curing adhesive makes the sensor suitable for high temperature and high pressure applications. The sensors were tested up to 2 MPa and 170°C in a nitrogen chamber. The maximum thermal error of ±1.74% and ±1% full scale output (FSO) were measured for SU-8 and UV sensors, respectively.

This content is only available via PDF.
You do not currently have access to this content.