Patent ID: 6632697
Filing Date: 2003-10-14
Classification: G01P,H01F,H05K

Abstract:
A method of making an acceleration sensor chip comprising:(a) a step for preparing a SOI wafer comprising a silicon substrate, a SiO2 layer and a silicon thin film; (b) a step for ion implanting a dopant at a position corresponding to a semiconductor strain gauge of said silicon thin film to form a diffusion resistor, and forming devices necessary for circuit construction on said silicon thin film; (c) a step for providing a protective film on the entire surface of said wafer, opening a plurality of through holes penetrating said silicon thin film by patterning and etching, and forming a weight part and a beam part connected to a support frame part on the periphery; (d) a step for removing said SiO2 layer under said weight part and said beam part by wet etching for forming said plurality of through holes while retaining said protective film; (e) a step for removing said protective film; (f) a step for coating a resist over the entire surface of said wafer; (g) a step for forming a slit by dicing for dividing said chip while retaining a small thickness of said wafer; (h) a step for removing by ashing said resist on said wafer by an O2 plasma; and (i) a step for dividing said chip by concentrating a stress on said slit.