Pressure sensor and preparation method thereof

Abstract

The invention provides a pressure sensor which can reduce the size and facilitate packaging and a preparation method of the pressure sensor, aiming at the defects of a pressure sensor structure in size and packaging technology in the prior art. The pressure sensor comprises a substrate (100), a pressure sensitive element (200) and an extraction electrode thereof, and a silicon through hole (50), wherein the pressure sensitive element (200) and the extraction electrode thereof are positioned on one side of the substrate (100), the silicon through hole (50) penetrates through the substrate (100), one end of the silicon through hole (50) is interconnected with the extraction electrode of the pressure sensitive element (200), the other end of the silicon through hole (50) is used as an output terminal of the pressure sensor, the pressure sensor also comprises a sealing cavity (40) positioned below the pressure sensitive element (200), and a pressure sensitive film is formed between the pressure sensitive element (200) and the sealing cavity (40).

Description

Technical field [0001] The invention relates to the field of semiconductors, in particular to a pressure sensor and a preparation method thereof. Background technique [0002] Since people discovered the piezoresistive effect of semiconductor silicon, piezoresistive pressure sensors have been rapidly developed and promoted. The piezoresistive effect refers to a physical phenomenon in which the electrical resistance or resistivity of a material changes significantly when it is subjected to pressure. [0003] The cross-sectional view of a pressure sensor that is currently widely used is as follows figure 1 As shown, where the number 101 refers to Si 3 N 4 , The number 102 refers to SiO 2 , The reference number 103 refers to Al, and the reference number 104 refers to the Si substrate. The core of the pressure sensor is a thin film structure including a piezoresistive bridge circuit located above the sealed cavity. The pressure-sensitive structure and circuit of the pressure sensor a...

AI Technical Summary

Problems solved by technology

The pressure-sensitive structure and circuit of the pressure sensor are fabricated above the device, and the film structure with the function of sensing external pressure cannot be inverted, so that the pressure sensor with this structure can only lead out electrical signals through wire bonding.

For the packaging of modern electronic products, due to the shortcomings of wire bonding technology, such as long interconnection delay, large inductance, low packaging efficiency, and incompatibility with wafer-level packaging, it is not conducive to the preparation of pressure sensors with this structure.

[0004] Another pressure sensor structure is to lead out the electrical signal of the pressure sensor through flip-chip bonding. Although it avoids the negative impact of wire bonding on the size and packaging of the pressure sensor device, it still needs to be integrated on the system board. Pressure signal processing circuit, and its preparation process is long, need to introduce silicon-silicon bonding, etc.

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