Application of the Selective Silicon Etching Methods for Estimation of the Wafers Quality in the Micromechanical Sensors

Silicon is one of the widely used materials in the manufacture of modern electronic components and functional electronics devices. The manufacturing quality of silicon plates determines the quality parameters of products. The purpose of the researched studies is to establish the causes of silicon rasters during anisotropic etching and the geometry violation of the formed structures to improve the quality parameters of the technological process of micromechanical sensors manufacturing. Based on the use of selective etching methods, the article presents the results of the quality parameters estimation of silicon wafers used in the micromechanical sensors manufacture. The detecting methods of swirl defects and dislocations are described. The method for determining swirl defects is based on the difference in the etching rate of a silicon wafer areas containing micro-defects compared to crystallographically perfect areas. The method of dislocations identifying is based on the fact that at the intersection of dislocations and the wafers surface, the rate of silicon etching is higher, as a result of which dislocations are revealed as etch pits. Photographs of the wafers surface with the identified defects types are presented. The use of methods for selective silicon etching allowed us to experimentally reveal two types of silicon wafer defects: swirl defects (micro-defects) and dislocations, which have different causes, described in the article. The presented techniques can be practically used at the input quality control of silicon wafers.