Pressure sensor with multiple parallel annular Wheatstone bridges and preparation method of pressure sensor

Abstract

The disclosure provides a pressure sensor with multiple parallel annular Wheatstone bridges and a preparation method of the pressure sensor. The pressure sensor comprises a substrate, a pressure sensitive unit, an insulating passivation layer, a wire layer and an etching stop layer; the pressure sensitive unit comprises a stress sensitive film, a plurality of piezoresistors and a plurality of leads, a cavity is formed in the first surface of the substrate in a thickness direction of the substrate, and the etching stop layer is arranged on the first surface of the substrate; the stress sensitive film is arranged on the etching stop layer, the plurality of piezoresistors are arranged on one side, deviating from the substrate, of the stress sensitive film, the plurality of piezoresistors arearranged in parallel at intervals, and the plurality of piezoresistors are electrically connected through the plurality of leads to form a plurality of parallel annular Wheatstone bridges; the insulating passivation layer is arranged on the side, deviating from the substrate, of the pressure sensitive unit, and a plurality of metallized via holes penetrating through the thickness of the insulatingpassivation layer are formed in the insulating passivation layer; and the wire layer is arranged on one side, deviating from the substrate, of the insulating passivation layer and is electrically connected with the corresponding lead through the metallized via hole. And the linearity and the sensitivity of the device can be effectively improved.

Description

technical field [0001] The disclosure belongs to the technical field of pressure sensors, and in particular relates to a pressure sensor with multi-parallel annular Wheatstone bridges and a preparation method for the pressure sensor with multi-parallel annular Wheatstone bridges. Background technique [0002] Traditionally, a pressure sensor includes a silicon substrate, a stress-sensitive film disposed on the silicon substrate, and four piezoresistors. The four piezoresistors are electrically connected to each other through leads to form a Wheatstone bridge structure. In the Wheatstone bridge structure, four varistors form a square. [0003] However, after several experimental studies by the inventors of the present disclosure, it is found that both the linearity and the sensitivity of the square Wheatstone bridge need to be improved. [0004] In addition, the traditional pressure sensor does not have an isolation structure around the piezoresistor, which leads to the poss...

AI Technical Summary

Problems solved by technology

[0003] However, through many experimental studies by the inventor of the present disclosure, it is found that the linearity and sensitivity of the square Wheatstone bridge need to be improved

[0004] In addition, the traditional pressure sensor does not have an isolation structure around the piezoresistor, which leads to the possibility of device leakage, which will increase the temperature drift effect of the device and reduce the reliability of the device

[0005] In addition, in the traditional pressure sensor, there is no shielding structure above and below the Wheatstone bridge structure, which will cause the upper and lower sides of the Wheatstone bridge structure to not be at the same potential, which is likely to cause static electricity and electromagnetic interference, resulting in device reliability reduce

Images