SiC high-temperature pressure sensor and packaging method thereof

Abstract

The invention discloses a SiC high-temperature pressure sensor and a packaging method thereof. The sensor comprises a SiC MEMS chip, an AlN carrier, an elastic metal film, a supporting tube shell, a heat conduction base and a plurality of conductive binding posts; the heat conduction base is installed in the supporting tube shell; the AlN carrier is fixedly installed on the heat conduction base; the SiC MEMS chip is fixedly arranged on the AlN carrier; the elastic metal film is arranged on the supporting tube shell above the SiC MEMS chip; a thinned self-sealing cavity is etched in the face, attached to the AlN carrier, of the SiC MEMS chip; the conductive binding posts penetrate through the heat conduction base from the lower end of the supporting tube shell and then are connected with anelectrode of the SiC MEMS chip; and an insulating layer is arranged between the conductive binding posts and the heat conduction base. The assembly structure is put into heat conduction silicone oil,and the elastic metal film is pressed into the supporting tube shell in a matched mode through an annular plug cap, so the SiC high-temperature pressure sensor packaging is completed. The chip packaging structure is low in packaging cost and good in reliability, completely isolates the chip from a medium, and can continuously work at the high temperature of 500 DEG C or above.

Description

technical field [0001] The invention belongs to the field of semiconductors, and relates to a semiconductor pressure sensor, in particular to a SiC high-temperature pressure sensor and a packaging method thereof, which are suitable for pressure measurement above 500°C. Background technique [0002] High-temperature pressure sensors have a wide range of application requirements in aerospace engines, heavy-duty gas turbines, and modern weaponry systems. Due to the particularity of the measurement environment, it is required that the sensor packaging structure can withstand a high temperature medium environment above 500 °C. Traditional Si pressure sensors and sapphire pressure sensors are difficult to guarantee high-performance work at a high temperature of 500°C due to the limitations of chip materials and packaging processes. SiC materials are wide-bandgap semiconductors with high mechanical strength, high thermal conductivity, High melting point, anti-corrosion, so there i...

AI Technical Summary

Problems solved by technology

The thickness specifications of general ALN substrate raw materials are 0.2mm, 0.3mm, 0.38mm, 0.5mm, 0.735mm, and 1mm, so suppliers need special raw material customization to manufacture ALN substrates with specific sizes and complex structures, which increases virtually. The production cycle is shortened, and the complexity of the process also increases the cost of materials

[0006] Many commercial high-temperature pressure sensors on the market use glass substrates as the transition layer between the SiCMEMS chip and the external ALN shell. The connection adopts a high-temperature sintering process, which is difficult to manufacture.

In addition, the thermal conductivity of high-temperature sealing glass is poor. If the temperature is very high, it is difficult for the thermocouple on the back of the sensor to monitor the accurate temperature in real time, and use the external circuit to make timely compensation to the sensor.

[0007] High-temperature pressure sensors are generally used in harsh environments such as military, aerospace, and high-temperature chambers. The hardness of the ALN material is not high, and it is easy to crack or pulverize during extreme reliability tests such as vibration and drop. In addition, the ALN shell is conductive The performance is not as good as the metal shell, which is not conducive to the ESD protection of the internal chip, and the anti-electromagnetic interference ability is poor, and there are hidden dangers of long-term reliability in military and aerospace applications.

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