Temperature drift self-compensating SOI pressure sensor

Abstract

The invention relates to a temperature drift self-compensating SOI pressure sensor. The sensor comprises an SOI substrate, the SOI substrate is provided with a bridge circuit resistor used for being configured into a Wheatstone bridge, a surface, corresponding to the bridge circuit resistor, of the SOI substrate is provided with a compensation resistor used for conducting temperature compensationon the Wheatstone bridge, and the compensation resistor and the bridge circuit resistor are provided with interconnection leads which are electrically connected. The bridge circuit resistor and the compensation resistor are isolated through an insulation isolation layer and a passivation layer, the insulation isolation layer covers the SOI substrate, and the passivation layer covers the insulationisolation layer. The SOI substrate corresponding to the other side of the bridge circuit resistor is etched to form a pressure cavity and a pressure sensitive film, wherein the pressure cavity and the pressure sensitive film are located right below the bridge circuit resistor. The sensor is compact in structure, capable of achieving temperature drift self-compensation and reducing cost, high in stability, good in consistency, suitable for batch production, wide in application range, safe and reliable.

Description

[0001] The present invention is a divisional application of a patent application filed on November 23, 2011 with the application number 201110375349.X and the invention name "Temperature Drift Self-Compensating SOI Pressure Sensor". technical field [0002] The invention relates to a pressure sensor, in particular to a temperature drift self-compensating SOI pressure sensor, which belongs to the technical field of MEMS sensors. Background technique [0003] The pressure sensor manufactured by using the piezoresistive effect of silicon is to use the ion implantation and diffusion process in the integrated circuit process to form a group of diffusion resistors with almost equal resistance values ​​on the surface of the silicon wafer, and form metal interconnections between the resistors, which are connected into Whiskers. power bridge. When the elastic sensitive diaphragm deforms under the action of external pressure to generate stress, the bridge resistance on it changes acco...

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Problems solved by technology

[0005] In addition, since the resistor is a temperature-sensitive device, the zero point and sensitivity of the pressure sensor before compensation will change with the change of temperature, which greatly affects the accuracy of the sensor, and it is usually compensated for temperature drift

At present, pressure sensor compensation is divided into two types: hardware compensation and software compensation. The former requires a lot of manpower to test the temperature drift of each chip before compensation within the operating temperature range, and then select different devices, such as diodes and thermistors. The consistency is poor and the workload is heavy; and the software compensation cost is high. At present, most of the domestic compensation is for imported ASIC chips. The high price also limits the development of the domestic sensor industry.

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