Micro electro mechanical system three-axis acceleration sensor chip and manufacturing method

Abstract

The invention provides a micro electro mechanical system three-axis acceleration sensor chip and a manufacturing method, and the chip comprises a first axis acceleration sensor unit which is used forsensing the acceleration in a first axis direction; the second axis acceleration sensor unit is used for sensing the acceleration in the second axis direction; the third-axis acceleration sensor unitis used for sensing the acceleration in the third-axis direction; the first axis acceleration sensor unit and the second axis acceleration sensor unit are arranged in a stacked mode. The third-axis acceleration sensor unit comprises a fourth acceleration sensor subunit and a fifth acceleration sensor subunit, the fourth acceleration sensor subunit is arranged on one side of the first-axis acceleration sensor unit, and the fifth acceleration sensor subunit is arranged on one side of the second-axis acceleration sensor unit; the fourth acceleration sensor subunit and the fifth acceleration sensor subunit are of an asymmetric structure. The first shaft acceleration sensor unit, the second shaft acceleration sensor unit and the third shaft acceleration sensor unit are sealed in the same sealing cavity.

Description

technical field [0001] The invention relates to the field of semiconductor chips, in particular to a microelectromechanical system three-axis acceleration sensor chip and a manufacturing method. Background technique [0002] Micro-Electro-Mechanical System (MEMS), hereinafter referred to as MEMS, refers to a sensor device with a size of a few millimeters or even smaller. Its internal structure is generally on the order of microns or even nanometers, and it is an independent intelligent system. The current MEMS acceleration sensor has a variety of implementation methods, which can be mainly divided into three types: piezoelectric, capacitive and thermal induction. Taking the technical principle of the capacitive three-axis accelerometer as an example, the capacitive accelerometer can sense motion conditions such as acceleration or vibration in different directions. It mainly uses the good mechanical properties of silicon to design a movable mechanical structure. As the accel...

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Problems solved by technology

The X, Y, and Z three-axis accelerometers of the three-axis accelerometer are on the same plane, which occupies a large chip area; and the Z-axis uses a comb-tooth method to measure capacitance. Compared with the flat-panel capacitance sensing method, this method The capacitance change value is small, the product range is small and the sensitivity is not high

[0006] In the third prior art (patent US20070059857A1), MEMS three-axis accelerometer X-axis and Y-axis accelerometer adopts spring and comb structure, Z-axis accelerometer adopts seesaw plate capacitor structure, such as image 3 As shown, the accelerometers of the X-axis, Y-axis, and Z-axis are on the same plane. This design requires a large chip area and high cost

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