MEMS (Micro Electro Mechanical Systems) pressure sensor and formation method thereof

Abstract

The invention relates to an MEMS (Micro Electro Mechanical Systems) pressure sensor and a formation method thereof. The formation method comprises the following steps of providing a first substrate comprising a first surface and a second surface which are opposite, wherein the first substrate comprises at least one conducting layer, and the conducting layer is located on one side of the first surface of the first substrate; providing a second substrate comprising a third surface and a fourth surface which are opposite, wherein the second substrate comprises a second base, a piezoresistive element and a pressure sensing area, and the piezoresistive element is located in the pressure sensing area and on one side of the third surface of the second substrate; mutually fixing the first surface of the first substrate and the third surface of the second substrate; forming a cavity between the first substrate and the pressure sensing area of the second substrate; removing the second base, and forming a fifth surface opposite to the third surface of the second substrate; forming a first conductive plug penetrating to the surface of the at least one conducting layer from one side of the fifth surface of the second substrate. The performance and the reliability of the MEMS pressure sensor are improved, and the size is reduced, and the processing cost is reduced.

Description

technical field [0001] The invention relates to the technical field of semiconductor manufacturing, in particular to a MEMS pressure sensor and a forming method thereof. Background technique [0002] Micro-Electro Mechanical System (MEMS for short) is an integrated device that acquires information, processes information and performs operations. Sensors in MEMS can receive external information such as pressure, position, velocity, acceleration, magnetic field, temperature or humidity, and convert the obtained external information into electrical signals for processing in MEMS. Common microelectromechanical systems include temperature sensors, pressure sensors, and humidity sensors. [0003] For the MEMS pressure sensor, its size is smaller, and its process precision, and its manufacturing process can be compatible with the manufacturing process of integrated circuit chips, thus greatly improving the cost performance. Current MEMS pressure sensors include piezoresistive pres...

AI Technical Summary

Problems solved by technology

[0006] In the existing manufacturing methods of MEMS pressure sensors, the process of integrating the pressure sensor chip and the signal processing circuit is quite different, and it is difficult to achieve monolithic integration.

At the same time, when the integrated circuit and the pressure sensor are fabricated on a single substrate, the existence of the pressure sensor has hindered the development of the integrated circuit, and the existence of the integrated circuit on the same substrate has also caused difficulties in the manufacture of small-sized pressure sensors.

Therefore, the manufacturing process of using a single substrate as an integrated circuit and a pressure sensor is more complicated, and the size of the formed device is larger, resulting in an increase in manufacturing cost

[0007] When making an integrated pressure sensor and circuit on a single substrate, if the components of the pressure sensor are made first, and then the circuit is made, the process of the pressure sensor often affects the substrate, resulting in a decrease in the yield of integrated circuits that is difficult to make

If the integrated circuit is made first, and then the pressure sensor is made, the existence of the integrated circuit has great restrictions on the choice of pressure sensor material and the temperature of the processing process, which will seriously reduce the performance of the pressure sensor

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