CMOS MEMS capacitance-type humidity sensor and preparation method thereof

Abstract

The invention relates to a CMOS MEMS capacitance-type humidity sensor and a preparation method thereof, and belongs to the technology of a semiconductor chip. A plurality of air subchannels are formed on a substrate in orthographic projection of a humidity sensing medium layer, the sensitivity of the sensor can be improved and the response time can be shortened by virtue of the air subchannels; moreover, a supporting column is formed between two adjacent air subchannels, so that the strength of a sensitive device area can be improved by virtue of the supporting column, the cracking of the humidity sensor in real application can be prevented, and under the situation that the sensitivity and the response time of the humidity sensor are guaranteed, the structural strength of the humidity sensor is improved; the CMOS MEMS capacitance-type humidity sensor formed by adopting the method is provided with the air subchannels and the supporting column, so that the structural strength of the capacitance-type humidity sensor can be improved under the situation that the sensitivity and the response time of the capacitance-type humidity sensor are guaranteed.

Description

technical field [0001] The invention relates to a CMOS MEMS capacitive humidity sensor and a preparation method thereof, belonging to semiconductor chip technology. Background technique [0002] Humidity sensors are widely used in many fields such as national defense aviation, meteorological detection, industrial control, agricultural production, medical equipment, etc. In recent years, an important direction for the development of humidity sensors is miniaturization. Existing miniature humidity sensors mainly include capacitive, resistive, piezoresistive and other types. Capacitive humidity sensors have been widely used in commercial fields due to their advantages of low power consumption and low cost. The use of standard CMOS technology to manufacture capacitive miniature humidity sensors has three advantages: (1) the sensor is small in size and has good consistency; (2) it is easy to monolithically integrate the humidity sensor and the detection circuit, which helps to i...

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Problems solved by technology

[0007] In addition, when the sensitivity and response time of the device are guaranteed, the structural strength of the device is often ignored. A fast-response CMOS relative humidity sensor involved in Chinese patent CN 101620197 B has a humidity sensitive medium above and below In contact with air, the effect of fast response is achieved, and the sensitivity of the device is not lost. However, since the bulk silicon under the sensitive area is corroded, the sensitive area is suspended as a whole, and the mechanical strength is difficult to be guaranteed. It is easy to break in practical applications.

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