CN106199071B - A kind of anti high overload lower range capacitance acceleration transducer and its manufacturing method - Google Patents

Abstract

The invention relates to a MEMS capacitive acceleration sensor, in particular to an anti-high overload low-range capacitive acceleration sensor and a manufacturing method thereof. The invention solves the problems that the existing MEMS capacitive acceleration sensor cannot realize stable output under high overload conditions, and cannot realize dynamic balance of high precision and high overload resistance. An anti-high overload and low-range capacitive acceleration sensor, including a four-cantilever beam structure and a glass electrode structure; the four-cantilever beam structure includes a silicon frame, a silicon mass, four silicon cantilever beams, and eight silicon dioxide protection platforms; The glass electrode structure includes two glass substrates and two metal electrodes. The invention is applicable to the fields of satellite navigation, missile guidance, cannonball orientation, automobile anti-shock protection, automatic braking, medical services and the like.

Description

A high-overload-resistant low-range capacitive acceleration sensor and its manufacturing method

technical field

The invention relates to a MEMS capacitive acceleration sensor, in particular to an anti-high overload low-range capacitive acceleration sensor and a manufacturing method thereof.

Background technique

MEMS capacitive acceleration sensors are widely used in satellite navigation, missile guidance, shell orientation, automobile shock protection, automatic braking, medical services and other fields. Under the existing technical conditions, MEMS capacitive acceleration sensors mainly include interdigital MEMS capacitive acceleration sensors, torsional MEMS capacitive acceleration sensors, cantilever beam MEMS capacitive acceleration sensors, sandwich MEMS capacitive acceleration sensors, etc. Practice has shown that the existing MEMS capacitive acceleration sensors generally have the following problems due to their own structure limitations: First, the existing MEMS capacitive acceleration sensors cannot achieve stable output under high overload conditions. Second, the existing MEMS capacitive acceleration sensor cannot achieve the dynamic balance of high precision and high overload resistance. Based on this, it is necessary to invent a brand-new MEMS capacitive acceleration sensor to solve the above-mentioned problems existing in the existing MEMS capacitive acceleration sensor.

Contents of the invention

In order to solve the problem that the existing MEMS capacitive acceleration sensor cannot realize stable output under high overload conditions, and cannot realize the dynamic balance of high precision and high overload resistance, the present invention provides a high overload resistance low-range capacitive acceleration sensor and its Manufacturing method.

The present invention is realized by adopting the following technical solutions:

An anti-high overload and low-range capacitive acceleration sensor, including a four-cantilever beam structure and a glass electrode structure;

The four cantilever beam structure includes a silicon frame, a silicon mass block, four silicon cantilever beams, and eight silicon dioxide protection platforms; the thickness of the silicon mass block is smaller than the thickness of the silicon frame; the thickness of the four silicon cantilever beams is the same, and the four The thickness of each silicon cantilever beam is less than the thickness of the silicon mass block; the outer end faces of the four silicon cantilever beams are respectively connected with the center of the four inner sides of the silicon frame, and the outer end sides of each silicon cantilever beam are connected with the silicon frame There are chamfers between the inner surfaces of the four silicon cantilever beams; the inner end surfaces of the four silicon cantilever beams are respectively connected with the center of the four sides of the silicon mass block, and the inner end sides of each silicon cantilever beam are connected with the side surfaces of the silicon mass block. There are chamfers between them; four of the silicon dioxide protection platforms are respectively fixed on the front four corners of the silicon mass block; the other four silicon dioxide protection platforms are respectively fixed on the reverse four corners of the silicon mass block;

The glass electrode structure includes two glass substrates and two metal electrodes; a through hole is opened between the front and back of each glass substrate; the two metal electrodes are respectively sputtered in the two through holes;

Two glass substrates are respectively bonded to the front and back of the silicon frame, and two metal electrodes are respectively facing the front and back of the silicon mass.

When working, the two metal electrodes are respectively connected to the external detection circuit through lead wires. The silicon mass and the first metal electrode together form the first capacitor structure. The silicon mass and the second metal electrode together form the second capacitance structure. The specific working process is as follows: when the sensor is impacted, the silicon mass moves up and down, and the distance between the silicon mass and the two metal electrodes changes (if the distance between the silicon mass and the first metal electrode increases , the distance between the silicon mass and the second metal electrode decreases. Conversely, if the distance between the silicon mass and the first metal electrode decreases, the distance between the silicon mass and the second metal electrode The distance increases), the capacitance value of the first capacitive structure and the capacitance value of the second capacitive structure both change. At this time, the external detection circuit detects the difference between the capacitance change of the first capacitive structure and the capacitance change of the second capacitive structure through two metal electrodes, and calculates the value of the impact acceleration according to the difference , thus realizing the detection of impact acceleration. In the above process, the silicon dioxide protective platform plays the following role: when the impact is too large, the silicon dioxide protective platform can prevent the silicon mass from being attached to the two metal electrodes to form electrostatic adsorption, and on the other hand, it can prevent The four silicon cantilever beams were broken due to excessive displacement of the silicon mass. The role of the chamfer is to reduce the impact on the four silicon cantilever beams to protect the integrity of the structure.

Based on the above process, compared with the existing MEMS capacitive acceleration sensor, a kind of anti-high overload low-range capacitive acceleration sensor of the present invention adopts a new structure, possesses the following advantages: A stable output is achieved. Second, the present invention realizes the dynamic balance of high precision and high overload resistance.

A method for manufacturing an anti-high overload and low-range capacitive acceleration sensor (the method is used to manufacture a high-overload-resistant and low-range capacitive acceleration sensor according to the present invention), the method is realized by the following steps:

a. Manufacture of the four-cantilever beam structure: first select the silicon wafer and clean the silicon wafer; then grow a silicon dioxide mask on the front and back sides of the silicon wafer, and form an etching pattern on the silicon dioxide mask; then According to the etching pattern, the front and back of the silicon wafer are wet-etched first, and then the front and back of the silicon wafer are dry-etched to obtain a four-cantilever beam structure;

b. Manufacture of the glass electrode structure: first select two glass substrates, and open a through hole between the front and back of each glass substrate; then sputter metal in the two through holes respectively, thus obtaining two a metal electrode;

c. Assembly of the four-cantilever beam structure and the glass electrode structure: bond two glass substrates to the front and back sides of the silicon frame respectively, and ensure that the two metal electrodes face the front and back sides of the silicon mass block respectively, thus obtaining Anti-high overload low-range capacitive acceleration sensor.

The invention effectively solves the problem that the existing MEMS capacitive acceleration sensor cannot realize stable output and high precision and high overload resistance dynamic balance under high overload conditions, and is suitable for satellite navigation, missile guidance, shell orientation, and automobile shockproof protection , automatic braking, medical services and other fields.

Description of drawings

Fig. 1 is a structural schematic diagram of a high overload resistance and low range capacitive acceleration sensor according to the present invention.

FIG. 2 is a schematic structural view of a four-cantilever beam structure of a high-overload-resistant and low-range capacitive acceleration sensor according to the present invention.

Fig. 3 is a structural schematic diagram of a glass electrode structure of a high-overload-resistant low-range capacitive acceleration sensor according to the present invention.

In the figure: 1-silicon frame, 2-silicon mass block, 3-silicon cantilever beam, 4-silicon dioxide protection platform, 5-chamfer, 6-glass substrate, 7-metal electrode.

Detailed ways

An anti-high overload and low-range capacitive acceleration sensor, including a four-cantilever beam structure and a glass electrode structure;

The four-cantilever beam structure includes a silicon frame 1, a silicon mass block 2, four silicon cantilever beams 3, and eight silicon dioxide protection platforms 4; the thickness of the silicon mass block 2 is less than the thickness of the silicon frame 1; the four silicon cantilever beams 3 have the same thickness, and the thicknesses of the four silicon cantilever beams 3 are all smaller than the thickness of the silicon mass block 2; A chamfer 5 is provided between the outer end side of the silicon cantilever 3 and the inner side of the silicon frame 1; the inner end faces of the four silicon cantilever beams 3 are connected to the center of the four sides of the silicon mass 2 respectively, And there is a chamfer 5 between the inner end side of each silicon cantilever beam 3 and the side of the silicon mass 2; four of the silicon dioxide protection platforms 4 are respectively fixed on the front four corners of the silicon mass 2; the other four The silicon dioxide protection platform 4 is respectively fixed on the opposite four corners of the silicon mass block 2;

The glass electrode structure includes two glass substrates 6 and two metal electrodes 7; a through hole is opened between the front and back of each glass substrate 6; two metal electrodes 7 are sputtered on the two through holes respectively Inside;

Two glass substrates 6 are respectively bonded to the front and back of the silicon frame 1 , and two metal electrodes 7 are respectively facing the front and back of the silicon mass 2 .

The silicon dioxide protection platform 4 can also be replaced by a silicon nitride protection platform.

A method for manufacturing an anti-high overload and low-range capacitive acceleration sensor (the method is used to manufacture a high-overload-resistant and low-range capacitive acceleration sensor according to the present invention), the method is realized by the following steps:

a. Manufacture of the four-cantilever beam structure: first select the silicon wafer and clean the silicon wafer; then grow a silicon dioxide mask on the front and back sides of the silicon wafer, and form an etching pattern on the silicon dioxide mask; then According to the etching pattern, the front and back of the silicon wafer are wet-etched first, and then the front and back of the silicon wafer are dry-etched to obtain a four-cantilever beam structure;

b. Manufacture of the glass electrode structure: first select two glass substrates 6, and open a through hole between the front and back sides of each glass substrate 6; then sputter metal in the two through holes respectively, thus Obtain two metal electrodes 7;

c. Assembly of the four cantilever beam structure and the glass electrode structure: bond two glass substrates 6 to the front and back of the silicon frame 1 respectively, and ensure that the two metal electrodes 7 face the front and back of the silicon mass 2 respectively , thus obtaining a high-overload-resistant low-range capacitive acceleration sensor.

The silicon dioxide mask can also be replaced by a silicon nitride mask.

Claims (2)

1. a kind of manufacturing method of anti high overload lower range capacitance acceleration transducer, it is characterised in that：This method is for making Make a kind of anti high overload lower range capacitance acceleration transducer as described below；

The anti high overload lower range capacitance acceleration transducer, including four cantilever beam structures and glass electrode structure；

Four cantilever beam structure includes silicon frame（1）, siliceous gauge block（2）, four silicon cantilevers（3）, eight silica it is anti- Protect platform（4）；Siliceous gauge block（2）Thickness be less than silicon frame（1）Thickness；Four silicon cantilevers（3）Consistency of thickness, and four Silicon cantilever（3）Thickness be respectively less than siliceous gauge block（2）Thickness；Four silicon cantilevers（3）Outer end end face respectively with silicon side Frame（1）Four medial surface centers be connected as one, and each silicon cantilever（3）Outer end side surface and silicon frame（1）Inside Chamfering is equipped between face（5）；Four silicon cantilevers（3）Inner end end face respectively with siliceous gauge block（2）Four flanking centrals It is connected as one, and each silicon cantilever（3）Interior end side surface and siliceous gauge block（2）Side between be equipped with chamfering（5）；Its In four silica protecting stands（4）It is individually fixed in siliceous gauge block（2）Positive quadrangle；Four additional silica protecting stand （4）It is individually fixed in siliceous gauge block（2）Reverse side quadrangle；

The glass electrode structure includes two glass substrates（6）, two metal electrodes（7）；Each glass substrate（6）Front Through-hole there are one opening up is penetrated through between reverse side；Two metal electrodes（7）It is sputtered in respectively in two through-holes；

Two glass substrates（6）It is bonded to silicon frame respectively（1）Obverse and reverse, and two metal electrodes（7）Respectively with silicon Mass block（2）Obverse and reverse face；

This method is realized using following steps：

A. the manufacture of four cantilever beam structures：Silicon chip is chosen first, and silicon chip is cleaned；Then in the obverse and reverse of silicon chip Earth silicon mask is grown, and forms etched features on earth silicon mask；Then according to etched features, just to silicon chip first Face and reverse side carry out wet etching, then carry out dry etching to the obverse and reverse of silicon chip, thus obtain four cantilever beam structures；

B. the manufacture of glass electrode structure：Two glass substrates are chosen first（6）, and in each glass substrate（6）Front and Perforation opens up a through-hole between reverse side；Then the splash-proofing sputtering metal in two through-holes respectively, thus obtains two metal electrodes （7）；

C. the assembling of four cantilever beam structures and glass electrode structure：By two glass substrates（6）It is bonded to silicon frame respectively（1）'s Obverse and reverse, and ensure two metal electrodes（7）Respectively with siliceous gauge block（2）Obverse and reverse face, thus resisted High overload lower range capacitance acceleration transducer.

2. a kind of manufacturing method of anti high overload lower range capacitance acceleration transducer according to claim 1, special Sign is：The earth silicon mask can also be substituted with silicon nitride mask.