Semiconductor sensor chip and method for producing the chip, and semiconductor sensor and package for assembling the sensor

摘要

The present invention is a method of making an acceleration sensor chip. The sensor chip is prepared from a SOI wafer having a silicon substrate, a SiO2 layer and a silicon thin film. A dopant is ion implanted at a position corresponding to a semiconductor strain gauge on the silicon thin film to form a diffusion resistor, and for forming devices necessary for circuit construction on said silicon thin film. A protective film is provided on the entire surface of the wafer, and a plurality of through holes penetrating the silicon thin film are formed by patterning and etching to make a weight part and a beam part connected to a support frame part on the periphery. The SiO2 layer under the weight part and the beam part is removed by wet etching to form the through holes, while leaving the protective film in place. The protective film is removed and a resist coated over the entire surface of the wafer. A slit for dividing the chip is formed part way through the wafer by dicing. The resist is removed by ashing with an O2 plasma and the chip is divided by concentrating a stress on the slit.