Fabrication of novel three-dimensional microstructures by the anisotropic etching of (100) and (110) silicon

Abstract

The anisotropic etching of single crystal silicon of (100) and (110) orientation in a solution of pyrocatechol, ethylene diamine, and water is reviewed and the fabrication of three novel types of micro-structures is described in detail. Controlled etching of Si, which is required to fabricate devices with a predictable geometry depends on an accurately oriented, defect-free substrate, a well-defined and aligned pattern geometry, and rigorously clean etching conditions. Conventional IC processing methods were used to fabricate: 1) a high-precision circular orifice in a thin p+Si membrane for use as an ink jet nozzle, 2) a multisocket miniature electrical connector with octahedral cavities suitable for cryogenic applications, and 3) multichannel arrays in (100) and (110) Si useful in various applications, e.g., charge electrodes, physical masks, and optical devices. To make some of these structures, a novel bonding technique to fuse silicon wafers with phosphosilicate glass films was developed. Copyright © 1978 by The Institute of Electrical and Electronics Engineers, Inc.