Performance and package effect of a novel piezoresistive pressure sensor fabricated by front-side etching technology

By applying the etching via technology, this study proposes a novel front-side etching fabrication process for a silicon-based piezoresistive pressure sensor to replace the conventional back-side bulk micro-machining. This novel structure pressure sensor can achieve the distinguishing features of the chip size reduction and fabrication costs degradation. In order to investigate the sensor performance and the sensor packaging effect of the structure proposed in this research, the finite element method was adopted for analyzing the sensitivity of the sensor signal. The signal sensitivity of the novel sensor after packaging was studied by applying mechanical as well as thermal loading to the sensor. Furthermore, the fabrication process and the sensor performance of the novel pressure sensor were compared with the conventional back-side etching type pressure sensor for the feasibility validation of the novel sensor. The results showed that the novel pressure sensor provides better sensitivity than that of the conventional one, and the sensor output signal variation due to package-induced thermal stress can be reduced by better packaging structure designs presented in this study. Based on the above findings, this novel structure pressure sensor shows a high potential for membrane type micro-sensor applications.