Microphone chip and its preparation method

A microphone and chip technology, which is applied in the field of improved microphone chip structure and its preparation, can solve the problems of microphone sensitivity drop, aging cracking, etc., and achieve the effects of avoiding aging cracking, reducing stress, and improving sensitivity

Inactive Publication Date: 2005-02-16
INST OF ACOUSTICS CHINESE ACAD OF SCI
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0003] The purpose of the present invention is to overcome the defects that the square vibrating membrane produced by the existing manufacturing process has a large stress at the sharp corner, which leads to a decrease in the sensitivity of the microphone and even an aging crack, thereby providing a circular isolation layer and a circular diaphragm. A microphone chip with an air gap; and a microphone chip with high sensitivity using two different film materials as a circular ring isolation layer and a circular sacrificial layer and a preparation method thereof

Method used

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  • Microphone chip and its preparation method
  • Microphone chip and its preparation method
  • Microphone chip and its preparation method

Examples

Experimental program
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Effect test

Embodiment 1

[0035] A kind of microphone chip provided by the present embodiment comprises an n-type silicon substrate 1, and boron is diffused on the front side of the silicon substrate 1 to form a p+ type doped layer 3 with a thickness of 3 or 20 microns; on the p+ type doped layer 3 deposited SiO 2 And photolithography, etch to form a ring-shaped isolation layer 4, the inner diameter of the annular isolation layer 4 is 500 or 3000 microns, and the radial width is 50 or 300 microns; a layer of silicon nitride is attached on the isolation layer 4. Circular vibrating membrane layer 6, deposition, photolithography, corrosion circular aluminum film and square electrode 9 on the vibrating membrane layer 6; as Figure 5 Shown; There is a layer of silicon nitride protection film 10 on the reverse side of the silicon substrate 1, a trapezoidal notch is etched out from the bottom surface of the silicon substrate 1, the depth of the trapezoidal notch reaches the p+ type doped layer 3, perpendicula...

Embodiment 2

[0037] Adopt preparation method of the present invention to prepare a microphone chip, its steps are as follows:

[0038] (1) n-type silicon wafer 1 undergoes a conventional high-temperature oxidation process to produce silicon dioxide 2 with a thickness of 0.5 microns. After photolithography, the high-temperature silicon dioxide is etched with hydrofluoric acid as a mask, and deep boron diffusion is performed on the front side of the silicon wafer. Form the p+ type doped layer 3 of the back plate, the depth is 5 microns, wherein the perforated part does not diffuse; as attached figure 1 shown.

[0039](2) Remove the high-temperature silicon dioxide mask with hydrofluoric acid; use plasma-enhanced chemical vapor deposition (PECVD) to deposit low-temperature silicon dioxide (LTO) on the front of the silicon wafer with a thickness of 0.5 microns, photolithography, hydrogen Fluoric acid corrodes the pattern of the annular isolation layer 4, the inner diameter of the annular ring...

Embodiment 3

[0044] (1) n-type silicon wafer 1 undergoes high-temperature oxidation to produce silicon dioxide with a thickness of 2 microns. After photolithography, use hydrofluoric acid to etch high-temperature silicon dioxide as a mask, and perform deep boron diffusion on the front of the silicon wafer to form a backplane The p+ type doped layer 3 has a depth of 15 microns, wherein the perforated part does not diffuse;

[0045] (2) Remove the high-temperature silicon dioxide mask with hydrofluoric acid; use plasma-enhanced chemical vapor deposition (PECVD) to deposit low-temperature silicon dioxide (LTO) on the front of the silicon wafer with a thickness of 6 microns, photolithography, hydrogen After hydrofluoric acid corrodes the annular isolation layer 4 pattern, the inner diameter of the annular ring is 3000 microns, and the width of the annular ring is 300 microns; Zinc oxide (ZnO) is deposited as a sacrificial layer by magnetron sputtering, with a thickness of 5 microns and a circul...

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Abstract

The method includes following steps: diffusing boron on front face of n- type silicon base plate to form p+ type doped layer; then depositing silicon dioxide on the said doped layer; then forming isolation layer through etching and eroding; attaching a diaphragm layer, depositing metal aluminum film on diaphragm layer and quadrate aluminum electrode; there is a layer of protective film made from silicon nitride on back face of silicon base plate; eroding a trape notch on underside of silicon base plate till p+ type doped layer, and eroding upwards to form acoustics hole perforated through back board; there is a air gap between the perforated back board and diaphragm layer made from silicon nitride. The method for fabricating chip of microphone is simple. The chip includes circular isolation layer and circular sacrificial layer made from different metal materials. Circular structure reduces stress of diaphragm, raises sensitivity of diaphragm so as to avoid aging cracking.

Description

technical field [0001] The invention relates to the technical field of a silicon microcapacitance microphone, in particular to an improved microphone chip structure and a preparation method thereof. Background technique [0002] The silicon microcapacitor microphone is composed of a silicon chip part and a peripheral circuit part forming a silicon microcapacitor, wherein the silicon chip part consists of a silicon substrate and a perforated (acoustic hole) backplane, air gap, isolation layer, vibrating membrane, and metal film. and metal electrodes. The usual silicon microcapacitor microphone is limited by the production method, and the air gap, isolation layer, and diaphragm are generally square, such as Micro Electro Mechanical Systems (MEMS), 1998 IEEE11th International Workshop p580-585, by P.-C. As described in "A HIGH SENSITIVITY POLYSILICON DIAPHRAGM CONDENSERMICROPHONE" by Hsu, C.H. Mastrangelo, and K.D. Wise. When making the silicon microcapacitor microphone, the ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H04R19/04H04R31/00
Inventor 徐联汪承灏黄歆魏建辉李俊红
Owner INST OF ACOUSTICS CHINESE ACAD OF SCI
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