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Silicon micro piezoelectric sensor chip and its preparing method

A sensor chip, micro-piezoelectric technology, applied in piezoelectric devices/electrostrictive devices, electrical components, impedance networks, etc., can solve the problems of reducing the sensitivity and yield of micro-sensors, decreasing sensor sensitivity, and large stress on the vibrating membrane. , to achieve the effect of reducing corrosion defects, reducing stress inhomogeneity and fast corrosion rate

Inactive Publication Date: 2008-05-14
INST OF ACOUSTICS CHINESE ACAD OF SCI
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

In this way, when the diaphragm and the silicon substrate are in a square shape, the stress on the diaphragm is greater, especially at the sharp corners, resulting in stress concentration, which in turn leads to a decrease in the sensitivity of the sensor and even aging cracks
The square film formed in this way naturally reduces the sensitivity and yield of the microsensor

Method used

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  • Silicon micro piezoelectric sensor chip and its preparing method
  • Silicon micro piezoelectric sensor chip and its preparing method
  • Silicon micro piezoelectric sensor chip and its preparing method

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0047] Embodiment 1, using the preparation method of the present invention to prepare a novel piezoelectric sensor chip, the steps are as follows:

[0048] 1) Clean n-type silicon substrate 1

[0049] Cleaning the n-type silicon substrate 1 with an acid cleaning solution and an alkaline cleaning solution respectively, and then rinsing it with deionized water;

[0050]2) On the front and back surfaces of the n-type silicon substrate 1, respectively deposit a silicon nitride base film layer 2 with a thickness of 0.2 μm and a silicon nitride mask layer 9 with a thickness of 0.2 μm by using chemical vapor deposition equipment;

[0051] 3) Preparation of zinc oxide sacrificial layer 3

[0052] Coating a positive photoresist on the surface of the silicon nitride base film layer 2, and exposing by photolithography to form a circular sacrificial layer inverted film photolithographic pattern;

[0053] Then use a plasma etching machine to photoetch the silicon nitride base film layer ...

Embodiment 2

[0067] Embodiment 2, using the preparation method of the present invention to prepare a novel piezoelectric sensor chip, the steps are as follows:

[0068] 1) Clean n-type silicon substrate 1

[0069] Cleaning the n-type silicon substrate 1 with an acid cleaning solution and an alkaline cleaning solution respectively, and then rinsing it with deionized water;

[0070] 2) On the front and back surfaces of the n-type silicon substrate 1, respectively deposit a silicon nitride base film layer 2 with a thickness of 2 μm and a silicon nitride mask layer 9 with a thickness of 2 μm by using chemical vapor deposition equipment;

[0071] 3) Preparation of phosphosilicate glass sacrificial layer 3

[0072] Coating a positive photoresist on the surface of the silicon nitride base film layer 2, and exposing by photolithography to form a circular sacrificial layer inverted film photolithographic pattern;

[0073] Then use a plasma etching machine to photoetch the silicon nitride base fil...

Embodiment 3

[0087] Embodiment 3, using the preparation method of the present invention to prepare a novel piezoelectric sensor chip, the steps are as follows:

[0088] 1) Clean n-type silicon substrate 1

[0089] Cleaning the n-type silicon substrate 1 with an acid cleaning solution and an alkaline cleaning solution respectively, and then rinsing it with deionized water;

[0090] 2) On the front and back surfaces of the n-type silicon substrate 1, a silicon nitride base film layer 2 with a thickness of 1 μm and a silicon nitride mask layer 9 with a thickness of 1 μm are respectively deposited by chemical vapor deposition equipment;

[0091] 3) Preparation of zinc oxide sacrificial layer 3

[0092] Coating a positive photoresist on the surface of the silicon nitride base film layer 2, and exposing by photolithography to form a circular sacrificial layer inverted film photolithographic pattern;

[0093] Then use a plasma etching machine to photoetch the silicon nitride base film layer 2, ...

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Abstract

The invention relates to a silicon micro piezoelectric sensor chip, which comprises: big-end-down square-pyramid holes on center of N-type silicon substrate, a deposited silicon nitride base film layer and mask layer on front and reverse surface of substrate, a circular hole on center of base film layer, a square hole on mask layer center with same size as the one on silicon substrate reverse surface, a silicon nitride vibration film on top surface of base film layer with circular upper electrode and lower electrode that has circular piezoelectric film on its top surface with circular low-temperature silicon oxide film protection layer by photo etching. Wherein, the silicon nitride or multicrystal silicon vibration film and piezoelectric film form circular piezoelectric film / silicon nitride or multicrystal silicon composite bending vibration film. This invention can reduce the unevenness of vibration stress to prevent film breakage, and improves sensitivity of sensor.

Description

technical field [0001] The invention relates to the field of silicon micro piezoelectric sensors, in particular to a silicon micro piezoelectric sensor chip and a preparation method thereof. Background technique [0002] The silicon micro piezoelectric sensor is composed of a silicon chip part and a peripheral circuit part, in which the silicon chip part consists of a silicon substrate and a perforated backplane on it, a supporting isolation wall, a piezoelectric layer / Si 3 N 4 Or polysilicon composite bending diaphragm and metal electrodes. Nowadays, the vibrating membranes of general silicon micro piezoelectric sensors are square, as described in "Silicon SubminiatureMicrophones with Organic Piezoelectric Layers", Ralf Schellin, etc., and "PiezoelectricCantilever Microphone and Microspeaker", Seung S.Lee, etc., due to the known In the process, there is anisotropy of etching when releasing the sacrificial layer, so only the backplane with square holes can be produced, suc...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H01L41/08H03H9/15
Inventor 杨楚威黄歆李俊红汪承灏解述徐联
Owner INST OF ACOUSTICS CHINESE ACAD OF SCI
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