Buried Mask Wet Etching Process of Silicon Micromechanical Structure

Abstract

The invention discloses a pre-buried mask wet etching process for a silicon micro mechanical structure. The pre-buried mask wet etching process comprises the following steps of: preparing a carbon dioxide thin film layer, preparing mask patterns (namely an initial mask pattern and a pre-buried mask pattern), performing wet etching for the first time, opening the pre-buried mask pattern, performing wet etching again and the like. By the process, a set of mask patterns can be stored on a mask layer on the surface of a silicon slice and the mask patterns can be retrieved at any time during anisotropic wet etching, so that the difficulty in a coating and photoetching process for an etched silicon slice can be avoided; and a novel method for manufacturing a multilayer micro mechanical structure on the silicon slice is provided.

Description

technical field [0001] The invention relates to the field of micromachining, in particular to a wet etching process for silicon micromechanical structures. Background technique [0002] The anisotropic wet etching technology of silicon has good direction selectivity, and has become one of the important means of silicon micromachining. Widely used in the fabrication of silicon micromechanical structures. [0003] When performing anisotropic wet etching on single crystal silicon, a mask layer needs to be formed on the surface of the silicon wafer, and the generation of the mask pattern is usually completed by coating-photolithography-development-etching. In order to use wet etching technology to obtain some complex silicon micromechanical structures, it is usually necessary to change the pattern of the mask during the etching process. The current main implementation method is to interrupt the etching and re-coat the surface of the silicon wafer-photolithography- The developm...

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Problems solved by technology

[0004] However, there are some problems in the actual operation process, for example: (1) if figure 1 As shown, after a period of corrosion of the silicon wafer, many grooves have been formed on the surface of the silicon wafer. The uniformity of coating on this surface by spin coating is very poor, which cannot meet the requirements of photolithography and cannot complete the precise transfer of graphics. , spraying can apply glue on the uneven surface, but the spraying equipment is expensive, and the thickness uniformity of the sprayed glue layer is not as good as that of the spin-coated glue layer, which affects the lithography accuracy; (2) such as figure 2 As shown, when the surface of the silicon wafer has been corroded to form some very thin film structures, and then the silicon wafer is coated with glue and photolithography, the vacuum suction sheet can easily destroy these film structures, thereby damaging the device. The dotted line in the figure is the suction The shape of the thin film structure when it is deformed after the film

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