Processing method for double-mask silicon on insulator (SOI) micro electro mechanical system (MEMS)

Abstract

The invention provides a processing method for a double-mask silicon on insulator (SOI) micro electro mechanical system (MEMS), which belongs to the field of MEMS micro-processing. An SOI wafer comprises a silicon structural layer, a silicon substrate layer and an insulation layer arranged between the silicon structural layer and the silicon substrate layer. Heavy boron doping is conducted on the silicon structural layer of an SOI wafer sheet, and doping concentration is larger than 5*1018 / cm3. The method includes sputtering a layer of aluminum on the front of a silicon sheet, photoetching, etching aluminum, and defining a complete MEMS structural image on the silicon sheet; photoetching and forming a thin line width structure image on the silicon sheet; etching a thin line width structure by using an inductively coupled plasma (ICP) etching method; removing photoetching glue, and using the ICP etching method for etching the wide thin line width structure simultaneously; etching the insulation layer below the structural layer; and using a KOH solution corrosion method to etch a silicon substrate. The processing method can use an SOI material to manufacture various MEMS devices and has the advantages of being good in controllability of structural layer thickness, reducing footing effect and parasitic capacitance, being simple in processing flow and the like.

Description

technical field [0001] The present invention relates to the micro-machining technical field of micro-electromechanical systems, in particular to a micro-machining process research on a double-mask silicon on insulator (Silicon on insulator, SOI) micro-electromechanical systems (Micro-electromechanical Systems, MEMS) processing method. Background technique [0002] In recent years, SOI technology has made great progress, and its application in the MEMS field has the following advantages: the monocrystalline silicon structure layer has excellent mechanical properties; the SiO2 buried oxide layer as a sacrificial layer and insulating layer has excellent corrosion stop capability, In MEMS processing, it is easy to obtain a complete, defect-free, uniform thickness and precisely controlled structural layer; the thickness of the structural layer can be increased; the all-silicon structure is compatible with the CMOS process and can be integrated with denser circuits. Therefore, com...

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Problems solved by technology

[0003] However, the main problems faced by the current SOI MEMS processing technology are: the increase of the parasitic capacitance of the all-silicon structure; the Footing effect of SOI in DRIE, etc.

In order to overcome these problems, research on SOI MEMS processing technology is being carried out extensively at home and abroad, but the existing processing methods can only reduce the parasitic capacitance, or can only reduce the Footing effect. Therefore, it is necessary to develop a method that can reduce the parasitic capacitance. A processing method that can improve the Footing effect

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