Ceramic Package Solutions for MEMS Sensors

Abstract

Implementation of microelectroMechanical systems (MEMS) sensors continues to increase as MEMS technology gains acceptance as a reliable and cost competitive design solution. Ceramic packages are one option that can offer the environmental protection for the sensor, and ceramic can also help the sensor achieve a miniaturized, flexible design solution that is capable of meeting the most demanding requirements. With flexural strengths between 400-620 MPa, thermal conductivities between 14-21 W/mK, and thermal coefficient of expansions ranging between 6.9-7.2 ppm/degC, the ceramic package can provide a stable platform to mount sensors that are sensitive to external stresses. Furthermore, if the sensor is sensitive to atmospheric conditions, ceramic packages can also offer a hermetic seal, capable of meeting a leak rate of 1 times 10-8 Std cc He/sec (at one atmosphere). To meet the demands of miniaturization, ceramic packages can provide multiple die packaging arrangements, internal cavity structures, 50 mum vias and lines/spaces, footprints as small as 3 mm times 3 mm and package profiles less than 1 mm. The following paper will illustrate how ceramic packages have kept up with the miniaturization requirements of the most demanding MEMS sensors. It will show the trends of MEMS sensors and it will also show why ceramic remains an excellent packaging choice for MEMS packaging designers. Lastly, it will discuss new developments in ceramic packaging, which demonstrate how ceramic will continue to be a viable packaging material for future MEMS sensor designs.