mems device and its manufacturing method

Abstract

The invention discloses an MEMS (Micro Electro Mechanical systems) device, comprising a substrate with a first cavity; a first sacrificial layer which is located on the substrate and is equipped with a second cavity; a vibration diaphragm layer, wherein at least one part of the vibration diaphragm layer is supported by the first sacrificial layer, and the vibration diaphragm layer comprises vibration diaphragm located above the second cavity, and the surface of the vibration diaphragm facing towards the second cavity is equipped with projecting points projecting to the second cavity; a second sacrificial layer which is located on the vibration diaphragm and is equipped with a third cavity, wherein at least one part of the vibration diaphragm is located in the third cavity; a back polar plate layer which is located on the second sacrificial layer, wherein at least one part of the back polar plate layer is supported by the second sacrificial layer, and the back polar plate layer comprises a back polar plate located above the third cavity; and anti-adhesion layers which is located on all naked surfaces between the substrate and the vibration diaphragm layer, and between the back polar plate layer and the vibration diaphragm. According to the device and the method, the contact area between the vibration diaphragm and the substrate can be reduced; and the adhesion between the substrate and the vibration diaphragm layer, and between the back polar plate layer and the vibration diaphragm can be effectively reduced or prevented due to the hydrophobicity and low-surface adhesion of the anti-adhesion layers.

Description

technical field [0001] The invention belongs to the technical field of MEMS, and more specifically relates to a double anti-adhesion method that uses a sacrificial layer to form an anti-adhesion bump and forms an aluminum oxide anti-adhesion layer between a moving mass layer and a polycrystalline buried layer or a substrate. Adhesive MEMS devices and methods of fabrication thereof. Background technique [0002] MEMS technology is known as a revolutionary high-tech in the 21st century. Its development began in the 1960s. MEMS is the abbreviation of Micro Electro Mechanical Systems in English, that is, micro-electro-mechanical systems, which is an ingenious combination of microelectronics and micromechanics. In the silicon-based MEMS processing technology, some products, such as capacitive micro-silicon microphones, have been researched for more than 20 years, and there are many ways to realize them. Cavity, sacrificial oxide layer, vibration diaphragm, insulating oxide layer...

AI Technical Summary

Problems solved by technology

In silicon-based MEMS processing technology, some products, such as capacitive micro-silicon microphones, have been researched for more than 20 years, and there are many ways to implement them. Cavity, sacrificial oxide layer, vibration diaphragm, insulating oxide layer, polycrystalline back plate, etc., but in the microstructure manufacturing and application process of micro-silicon microphone devices, when the surface adsorption force between the vibration diaphragm and the silicon substrate is greater than When the elastic recovery force of the microstructure is weakened, adhesion will occur between adjacent microstructures (substrate, vibrating diaphragm, back plate, etc.), which will lead to device failure and decrease the yield. Adhesion has become a micromachining and application process The main reason for the scrapping of finished products in this process seriously restricts the development and industrial application of capacitive micro-silicon microphones. In view of this, it is necessary to improve the structure and manufacturing method of existing capacitive micro-silicon microphones to solve the above problems

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