Preparation method of capacitive barometric sensor of micro-electronic-mechanical system

Abstract

The invention discloses a preparation method of a capacitive barometric sensor of a micro-electronic-mechanical system. The method comprises the following steps of: step 1), anisotropic deep reactive ion etching at the upper part of an N-type silicon substrate to form silicon corrosion holes; step 2), isotropic deep reactive ion etching on the silicon substrate to form a cavity; step 3), epitaxial growth of a monocrystalline silicon layer above the silicon substrate to form an epitaxy monocrystalline silicon layer; step 4), injection of phosphonium ions to form a phosphonium ion heavily doped diffusion area; step 5) chemical vapor deposition of an oxide layer and patterning; step 6), sputtering of a metal layer and patterning above the oxide layer; step 7), chemical vapor deposition of a passivation layer and patterning above the metal layer; and step 8), removal of part of the oxide layer by using a slow-release hydrofluoric corrosive liquid, to obtain a capacitance clearance cavity between a lower capacitance pole plate and an upper capacitance pole plate, thus forming the capacitive barometric sensor. The preparation method is compatible with the CMOS (Complementary Metal-Oxide-Semiconductor Transistor) standard process, and can be used for large scale production of the capacitive barometric sensor.

Description

technical field [0001] The present invention relates to a method for preparing an air pressure sensor, in particular to a method for preparing a capacitive air pressure sensor for a micro-electro-mechanical system (Micro-Electronic-Mechanical Systems, English for Micro-Electronic-Mechanical Systems, referred to as MEMS in the text). technical background [0002] Air pressure sensors play an increasingly important role in weather forecasting, climate analysis, environmental detection, aerospace and other aspects. Especially in recent years, frequent weather and natural disasters have made pressure sensors more important in weather forecasting and climate analysis. [0003] The application demand of air pressure sensor is huge. Due to the progress of MEMS technology, based on MEMS technology, it is expected to improve the performance of air pressure sensor and reduce the cost. Therefore, it has become a type of device mainly researched and developed by research institutions an...

AI Technical Summary

Problems solved by technology

However, silicon capacitive air pressure sensors still have the following main problems: first, polysilicon films are commonly used as deformable plates, but the mechanical properties and long-term stability of polysilicon are far inferior to those of monocrystalline silicon; second, vacuum chambers are generally made of silicon wafers. The formation of back corrosion, the alignment error of both sides and the alignment error when the capacitive structure needs to be formed by electrostatic bonding of glass with electrodes will cause the inconsistency of the performance of the same batch of sensors

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