Manufacturing method of movable mass block for micro electro mechanical system

Abstract

The invention provides a manufacturing method of a movable mass block for a micro electro mechanical system. The method comprises the following steps: providing monocrystal silicon with a front surface and a back surface; depositing a sacrificial layer on the front surface of the monocrystal silicon; depositing a polycrystalline silicon seed layer on the sacrificial layer; forming a polycrystalline silicon epitaxial layer on the polycrystalline silicon seed layer by adopting an epitaxy technique; selectively etching release holes, which penetrate through the polycrystalline silicon epitaxial layer and the polycrystalline silicon seed layer, on the upper surface of the polycrystalline silicon epitaxial layer by adopting a deep silicon etching technology to define a polycrystalline silicon mass block; and removing the sacrificial layer around the polycrystalline silicon mass block by corrosion through the release holes to release the polycrystalline mass block to be a movable structure. Compared with the prior art, in the manufacturing method of the movable mass block for the micro electro mechanical system, the polycrystalline silicon layer is formed on a monocrystal silicon piece by adopting the epitaxy polycrystalline silicon technology so as to manufacture the relatively big polycrystalline silicon mass block, consequently sensitivity of the micro electro mechanical system devices is improved and noise interference is reduced.

Description

【Technical field】 [0001] The invention relates to the technical field of micro-electro-mechanical systems, in particular to a method for manufacturing a movable mass block for micro-electro-mechanical systems. 【Background technique】 [0002] Micro Electro Mechanical Systems (MEMS for short) is the use of integrated circuit manufacturing technology and micro-processing technology to manufacture micro-structures, micro-sensors, micro-actuators, control processing circuits, and even interfaces, communications and power supplies in one or more blocks. Micro integrated system on a chip. With the development of MEMS technology, acceleration sensors and gyroscopes made of MEMS technology have been widely used in the field of automobiles and consumer electronics. The basic structures of acceleration sensors and gyroscopes include a movable mass, a large movable mass Can increase the sensitivity of the device and reduce noise interference. The preparation of movable masses for MEMS...

AI Technical Summary

Problems solved by technology

The preparation of movable masses for MEMS has become one of the key technologies for the development and practical application of MEMS devices, thus developing a variety of manufacturing methods for masses. The most commonly used method is LPCVD (Low pressure chemical vapor deposition, low pressure chemical vapor deposition), the polysilicon grains grown by this method are small and the growth rate is slow, and the growth thickness is generally about 1 μm. When the grown polysilicon is too thick, the The accumulation of by-products will cause losses to hardware such as pumps; in addition, SOI (Silicon-On-Insulator, silicon on insulating substrate) is also widely used in the preparation of mass blocks, but SOI is relatively expensive, which increases the process cost

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