Photolithographic packaging of silicon pressure sensors

The packaging technique presented here provides direct interaction between the sensing element and the physical or chemical variable to be measured as well as hermetic insulation and mechanical protection of the silicon sensor and its electrically active components. The sensors are embedded in a mechanically decoupling shell of silicone elastomer with low Young's modulus, leaving the sensing area free from covering. The process can be considered as a synthesis of conventional soft-mounting techniques and photolithographically controlled partial encapsulation. It has been applied to package piezoresistive silicon pressure sensors for use in humid environments and the results obtained show the suitability of the concept. Due to its modularity and unlike application-specific packaging methods, it can potentially be applied to a variety of microelectronic sensors. © 1998 Elsevier Science S.A. All rights reserved.