PHOTOLITHOGRAPHIC PACKAGING OF SILICON PRESSURE SENSORS

The packaging technique presented here provides direct interaction bet ween the sensing element and the physical or chemical variable to be m easured as well as hermetic insulation and mechanical protection of th e silicon sensor and its electrically active components. The sensors a re embedded in a mechanically decoupling shell of silicone elastomer w ith low Young's modulus, leaving the sensing area free from covering. The process can be considered as a synthesis of conventional soft-moun ting techniques and photolithographically controlled partial encapsula tion. It has been applied to package piezoresistive silicon pressure s ensors for use in humid environments and the results obtained show the suitability of the concept. Due to its modularity and unlike applicat ion-specific packaging methods, it can potentially be applied to a var iety of microelectronic sensors. (C) 1998 Elsevier Science S.A. All ri ghts reserved.