Surface acoustic wave high-temperature pressure sensor chip based on silicon wafer and piezoelectric thin film and preparation method of surface acoustic wave high-temperature pressure sensor chip

Abstract

The present invention provides a surface acoustic wave high-temperature pressure sensor chip based on a silicon wafer and a piezoelectric thin film and a preparation method of the surface acoustic wave high-temperature pressure sensor chip. The surface acoustic wave high-temperature pressure sensor chip comprises a silicon wafer chip substrate; the silicon wafer chip substrate includes a first surface and a second surface; a chamber is disposed inside the silicon wafer chip substrate; an opening at the second surface of the silicon wafer chip substrate is formed in the chamber, or the chamberis sealed by a second chip substrate bonded on the silicon wafer chip substrate so as to form a sealed chamber; the silicon wafer chip substrate above the chamber is a pressure-sensitive film; the piezoelectric thin film is formed on the pressure-sensitive film; and an interdigital transducer and a reflection grid are formed on the piezoelectric thin film. The surface acoustic wave high-temperature pressure sensor chip based on the silicon wafer and the piezoelectric thin film is small in size, can realize wireless receiving and transmitting when working at a radio frequency band, is flexiblein measurement mode and has a great potential application in the high-temperature pressure measurement field.

Description

technical field [0001] The invention belongs to the technical field of semiconductor design and manufacture, relates to MEMS sensors, in particular to a surface acoustic wave high-temperature pressure sensor chip based on silicon wafers and piezoelectric films and a preparation method thereof. Background technique [0002] Pressure measurement in high temperature environment is one of the key points and difficulties of measurement and control technology. In the fields of aerospace, national defense, petrochemical, and automobile industries, it is often necessary to measure and control pressure in a high-temperature environment. High-performance high-temperature pressure sensors are one of the key components in the above-mentioned fields. [0003] The silicon piezoresistive pressure sensor widely used at present uses a P-N junction to isolate the strain bridge and the strain film. Its technology is mature and its performance is excellent. , the performance of the sensor will...

AI Technical Summary

Problems solved by technology

[0003] The silicon piezoresistive pressure sensor widely used at present uses a P-N junction to isolate the strain bridge and the strain film. Its technology is mature and its performance is excellent. , the performance of the sensor will seriously deteriorate or even fail. In addition, silicon will undergo plastic deformation and current leakage at 600 ° C, resulting in extreme imbalance of signal processing systems and circuits.

The surface acoustic wave pressure sensor technology based on quartz is quite mature, but its working temperature is generally -20°C-100°C, and it is not suitable for use in an environment higher than 200°C

[0004] Chinese patent CN 1514219 provides a solid-state piezoresistive high-temperature-resistant pressure sensor, which realizes temperature measurement in harsh environments above 200°C. However, this sensor still needs power supply and wires to transmit signals, so it is difficult to meet the high temperature requirements above 500°C.

Chinese patent CN101775657 relates to the zero temperature compensation cutting type for high temperature application of gallium lanthanum silicate, but there is no in-depth work on the sensor for this crystal

Images