Method for producing an acceleration sensor

Abstract

A method for producing a semiconductor device that is capable of solving problems related to dicing a metal thin film used for electrochemical etching. According to the method, an n type epitaxial thin layer is formed on a p type single-crystal silicon wafer. An n.sup.+ type diffusion layer is formed in a scribe line area on the epitaxial layer. An n.sup.+ type diffusion layer is formed in an area of the epitaxial layer which corresponds to a predetermined portion of the wafer. An aluminum film is formed over the diffusion layers. The aluminum film has a clearance for passing a dicing blade. Portions of the wafer are electrochemically etched by supplying electricity through the aluminum film and the diffusion layers, to leave portions of the epitaxial layer. The wafer is diced into chips along the scribe line area. Each of the chips forms a separate semiconductor device. The electrochemical etching of the wafer is carried out after the formation of the aluminum film by immersing the wafer in a KOH aqueous solution and by supplying electricity through the aluminum film. The electrochemical etching is terminated at an inflection point where an etching current inflects to a constant level from a peak level. During the electrochemical etching, the diffusion layer reduces horizontal resistance in the epitaxial layer, so that the etched parts receive a sufficient potential to perform the etching.