mems device and its preparation method

Abstract

The invention provides a MEMS device and a preparation method thereof. A first insulating layer is formed on the front of a base, a vibrating film and a pole plate are formed on the first insulating layer, and a back cavity is formed on the back of the base. The back cavity exposes the vibrating membrane and faces away from the gap, and retains part of the first insulating layer as a supporting part of the vibrating membrane, and the vibrating membrane is opposite to the supporting part on the vibrating membrane The projection center is symmetrical, and the base in the back cavity that has an area facing the support part is reserved as the support base of the support part. When the vibrating membrane vibrates, it is between the edge and the center of the vibrating membrane Vibration occurs at the middle position of the MEMS device, which increases the effective vibration area, thereby improving the sensitivity and signal-to-noise ratio of the MEMS device, while reducing the amplitude of vibration, reducing the fluctuation range of sensitivity and signal-to-noise ratio; The force applied to the vibrating membrane in the mechanical reliability test, thereby increasing the reliability of the MEMS device.

Description

technical field [0001] The invention relates to the technical field of semiconductors, in particular to a MEMS device and a preparation method thereof. Background technique [0002] MEMS (Micro-Electro-Mechanical System, Micro-Electro-Mechanical System) technology refers to a micro-system that can integrate mechanical components, drive components, optical systems, and electronic control systems into a whole. It uses microelectronics technology and micromachining technology ( Such as silicon body micromachining, silicon surface micromachining, wafer bonding, etc.) combined manufacturing process, to produce a variety of excellent performance, low price, miniaturized sensors (such as inertial sensors, pressure sensors, acceleration sensors, etc.), execution drives, drives and microsystems. [0003] Existing MEMS devices generally include a base, the base has a front and a back, and the base has a back cavity that runs through the front and the back, a vibrating membrane is for...

AI Technical Summary

Problems solved by technology

[0004] However, since the vibrating membrane is equivalent to a thin film in motion, a relatively large amplitude will be generated in a relatively small effective vibration area, and the large vibration amplitude will cause the sensitivity of the device and the fluctuation range of the signal-to-noise ratio to increase, and in some Mechanical reliability tests will exert relatively large force on the vibrating membrane, such as air pressure test or mechanical impact test, which may easily cause loss or damage of the vibrating membrane

Images