Silicon substrate isotropic wet etching process

Abstract

The invention provides a novel silicon substrate isotropic wet etching process. The process includes forming two sacrificial layers on the surfaces of silicon substrates by adding negative 450-CP photo-resists, forming graphs needed to be machined through a surface micromachining photolithography technique, and using isotropic etching to obtain two-dimensional machined graphs with small depth-to-width ratios. According to the silicon substrate isotropic wet etching process, a certain quantity of acetic acids and water are added in a corrosion system selecting reasonable proportioning to serve as buffer agents to stabilize corrosion rates, and a corrosion solution is placed in an ice water mixture to control the reaction temperature to obtain a silicon corrosion system with an optimum corrosion rate, depth-to-width ratio and surface quality.

Description

technical field

[0001] The invention relates to the technical field of surface micromachining and manufacturing of semiconductor silicon materials, in particular to a silicon-based isotropic wet etching process. Background technique

[0002] The current silicon-based micromachining technology can be divided into two mainstreams: Surface Micromachining and Bulk Micromachining. The difference between silicon-based micromachining technology and traditional machining is that the design of the process is always arranged from the whole system first, and the top-down design method is adopted. Because the ratio of depth (thickness) to width (lateral dimension) of the movement mechanism of silicon surface micromachining is very small, it is called two-dimensional processing.

[0003] The general wet etching process of silicon is to first oxidize the surface of the material in the etching solution, and then dissolve one or more oxides through a chemical reaction, which is actually an...