Wet etching method for silicon semiconductor wafer

Abstract

Wet etching method and apparatus in which a wafer is processed so as to have a good flatness by making uniform a travel distance and a traveling velocity of an arbitrary point on a wafer surface relative to an etching solution, while rotating the wafer in the etching solution. An etching solution vessel comprises a pair of walls parallel to a plane of rotation of a wafer; and walls of curved surfaces, which intersect the pairs of walls at a right angle, and whose centers of curvature are the same, and which are spaced apart from each other along a radius of curvature with a distance of d therebetween; the etching solution is fed from a lower part of the vessel; and a flow velocity of the etching solution is adjusted at an arbitrary point between the pair of curved surfaces just before a stream of the solution contacts with a wafer rotating in the etching solution so that the flow velocity is a velocity (r.omega.), which is obtained by multiplying a distance r between the center of curvature and the arbitrary point with an angular velocity .omega. of the wafer or an approximation thereof.