Pressure sensor based on FBAR structure and preparation method thereof

A pressure sensor and substrate technology, applied in the field of sensors, can solve problems such as reducing pressure sensitivity, and achieve the effects of small range, fast response speed and high sensitivity

Pending Publication Date: 2022-04-08
苏州航凯微电子技术有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The air-gap structure can not only improve the structural stability, but also reduce the difficulty of the production process. It can be used to make micro pressure sensors, but the thickness of the substrate under the cavity of the conventional air-gap structure will reduce its sensitivity to pressure.

Method used

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  • Pressure sensor based on FBAR structure and preparation method thereof
  • Pressure sensor based on FBAR structure and preparation method thereof
  • Pressure sensor based on FBAR structure and preparation method thereof

Examples

Experimental program
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Embodiment 1

[0059] see figure 1 , in an embodiment of the present invention, a pressure sensor based on an FBAR structure includes a substrate 1, preferably, the substrate is a silicon wafer with a high resistance (100) crystal orientation, and a groove is opened on the top of the substrate 1, and the groove The depth is 1-30 μm, the surface of the substrate 1 is covered with an insulating layer 2, preferably, the insulating layer 2 is made of SiO 2 、Si 3 N 4 etc.; further, the material of the insulating layer 2 is SiO prepared by LPCVD or thermal oxygen oxidation process 2 , the thickness of the insulating layer 2 is 0.3-0.6 μm; the insulating layer 2 and the top groove of the base 1 surround the air chamber 10; the insulating layer 2 is covered with a supporting layer 3, preferably, the supporting layer 3 is made of For the preparation of Si by PECVD or LPCVD 3 N 4 , the supporting layer 3 has a thickness of 0.3-1 μm; the supporting layer 3 is provided with a piezoelectric oscillat...

Embodiment 2

[0063] see Figure 2-19 , on the basis of Example 1, the above-mentioned preparation method of the pressure sensor based on the FBAR structure includes substrate technology, packaging cap technology, substrate and packaging cap bonding, packaging cap thinning, preparing through holes on the packaging cap, filling through holes Preparation of grooves at the bottom of the hole and substrate, and etching of the packaging cap to expose the bottom electrode of the piezoelectric oscillation stack; the substrate process includes preparation of grooves at the top of the substrate, preparation of an insulating layer, filling of sacrificial layer materials, thinning and polishing of the sacrificial layer, and preparation of piezoelectric stacks; packaging The capping process includes preparation steps; specifically, the following steps are included:

[0064] 1) Wet etching a groove on the top of the silicon wafer substrate 1 with a high resistance (100) crystal orientation, with a depth...

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Abstract

The invention discloses a pressure sensor based on an FBAR structure, and relates to the technical field of sensors, the pressure sensor comprises a substrate, the top of the substrate is provided with a groove, and the surface of the substrate is covered with an insulating layer; the insulating layer and the groove in the top of the substrate enclose to form an air chamber; a supporting layer covers the insulating layer, and a piezoelectric oscillation pile is arranged on the supporting layer; a back groove is formed in the bottom of the substrate; the packaging cap is mounted at the top of the substrate in a bonding manner; a groove for accommodating the piezoelectric layer and the top electrode is formed in the bottom of the packaging cap; the packaging cap is further provided with a vertically-through through hole, the inner wall of the through hole is covered with a metal seed layer, and the through hole is further filled with through hole metal. The invention also discloses a preparation method of the pressure sensor. According to the sensor, pressure can be applied to the groove in the back of the substrate to cause deformation of the piezoelectric oscillation pile on the front side of the substrate, so that the output frequency of the piezoelectric oscillation pile is changed, and a mechanical signal is converted into an electric signal.

Description

technical field [0001] The invention relates to the technical field of sensors, in particular to a pressure sensor based on an FBAR structure and a preparation method thereof. Background technique [0002] At present, the structures of micro pressure sensors mainly include capacitive, piezoresistive, and mechanical resonance. Piezoresistive and capacitive micro pressure sensors are widely used in pressure sensors, their sensitivities are 0.01-1mV / (V·kPa) and 0.1-100fF / kPa respectively, and the output signals are analog electrical signals. Compared with piezoresistive sensors and capacitive sensors, the frequency signals of pressure sensors made of acoustic wave device structures (such as FBAR, SAW, etc.) have higher detection accuracy and accuracy, which also means that such sensors have higher resolution; at the same time, such sensors can be better used in passive wireless sensor systems. [0003] Film Bulk Acoustic Resonator (FBAR) is widely used in wireless communicati...

Claims

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Application Information

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IPC IPC(8): G01L1/10H01L41/113H01L41/22
Inventor 盖广洪白鹤
Owner 苏州航凯微电子技术有限公司
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