Pressure sensor and manufacturing method thereof

Abstract

The invention relates to a pressure sensor and a manufacturing method thereof. The pressure sensor comprises a substrate, an accommodating chamber, and an induction body; wherein the accommodating chamber is located in the substrate, including a bottom wall and side walls; and the induction body is suspended in the accommodating chamber; a deep groove is arranged between the induction body and theside wall of the accommodating chamber; a first chamber connected with the deep groove is arranged between the induction body and the bottom wall of the accommodating chamber; and the induction bodyand the side wall of the accommodating chamber are fixedly connected by a hanging beam in the deep groove. The induction body comprises a semiconductor layer, a medium layer located on the surface ofthe semiconductor layer, a closed second chamber that passes through the medium layer to the semiconductor layer, and a device layer covering the medium layer and the second chamber, wherein a piezoresistive strip is arranged on the surface of the device layer. The pressure sensor has a stress relief structure, and has a high reliability.

Description

technical field [0001] The invention relates to the field of micro-electromechanical systems, in particular to a pressure sensor and a manufacturing method thereof. Background technique [0002] MEMS (Micro-Electro-Mechanical Systems) technology is a high-tech that has developed rapidly in recent years. It uses advanced semiconductor manufacturing technology to realize batch manufacturing of MEMS devices. , weight and price have considerable advantages. [0003] The pressure sensor is one of the earliest MEMS products and is widely used in consumer electronics, medical fields, automotive electronics and other fields, such as electronic blood pressure monitors, tire pressure gauges, altimeters, weather forecasters, and automotive intake manifold sensors. etc. According to the working principle, it can be divided into piezoresistive, capacitive and piezoelectric. Among them, the piezoresistive pressure sensor has the advantages of large output signal, simple subsequent proc...

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Problems solved by technology

Another method commonly used at present is electrochemical corrosion. This method can obtain a lightly doped pressure-sensitive film on which piezoresistors can be made, but this method needs to add a relatively expensive potentiostat and use a special design. The fixture protects the front side from being corroded and applies voltage to the front side of the silicon wafer, which increases the equipment cost on the one hand, and increases the complexity of the process on the other hand, making the production efficiency very low

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