A leadless packaging structure and packaging method for a piezoresistive sensor

Abstract

The invention discloses a leadless packaging structure and packaging method of a piezoresistive sensor. The packaging structure comprises a silicon carbide chip, a silicon carbide cup, a kovar pin, abase, a metal shell and a first transition layer. A chip circuit is arranged on the front surface of the silicon carbide chip, and a first groove is formed in the back surface of the silicon carbide chip; a second groove is formed in the back surface of the silicon carbide cup; the front surface of the silicon carbide chip and the back surface of the silicon carbide cup are bonded together to forma bonding object; the kovar pin is inserted into the through hole in the silicon carbide cup sequentially through the base and the through hole in the first transition layer and is connected with themetal bonding pad; the bonding object, the base and the kovar pin are combined together through sintering and are fixed in an inner cavity of the metal shell; and the metal shell is fixed on the fixing piece through a thread structure. The high-temperature stability and reliability of the sensor are improved in a leadless packaging mode.

Description

technical field [0001] The invention relates to the technical field of sensor packaging, in particular to a leadless packaging structure and packaging method of a piezoresistive sensor. Background technique [0002] At present, most of the packaging forms of piezoresistive pressure sensors are packaging structures with wire leads. In some applications with relatively harsh conditions, such as high temperature applications (above 600 ° C), the sensor needs to have higher stability and reliability. The traditional wire lead method will bring unpredictable reliability problems, such as wire creep, softening and falling off. The leadless packaging structure will become the development direction of sensor packaging technology. [0003] The traditional wire lead packaging structure seals the front circuit of the sensor chip under the corrugated sheet filled with silicone oil, and the external pressure is indirectly transmitted to the pressure sensor chip through the corrugated sh...

AI Technical Summary

Problems solved by technology

[0003] The traditional wire lead packaging structure seals the front circuit of the sensor chip under the corrugated sheet filled with silicone oil, and the external pressure is indirectly transmitted to the pressure sensor chip through the corrugated sheet and the sealed silicone oil, resulting in the loss of the natural frequency of the sensor chip, which is not conducive to improving the performance of the sensor. responding speed

[0004] In addition, the traditional wire lead packaging structure will have problems such as thermal stress matching failure between packaging materials and thermal oxidation of packaging materials in high temperature environments, which will adversely affect the stability, response speed and natural frequency of the sensor chip.

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