CN117948957A - MEMS inertial integrated device and preparation method thereof - Google Patents
MEMS inertial integrated device and preparation method thereof Download PDFInfo
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- CN117948957A CN117948957A CN202410324705.2A CN202410324705A CN117948957A CN 117948957 A CN117948957 A CN 117948957A CN 202410324705 A CN202410324705 A CN 202410324705A CN 117948957 A CN117948957 A CN 117948957A
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- 238000002360 preparation method Methods 0.000 title claims abstract description 10
- 239000010410 layer Substances 0.000 claims abstract description 124
- 230000005855 radiation Effects 0.000 claims abstract description 111
- 238000007789 sealing Methods 0.000 claims abstract description 56
- 239000011241 protective layer Substances 0.000 claims abstract description 44
- 238000005530 etching Methods 0.000 claims abstract description 10
- 238000000605 extraction Methods 0.000 claims description 30
- 238000000034 method Methods 0.000 claims description 30
- 238000005086 pumping Methods 0.000 claims description 26
- 238000004519 manufacturing process Methods 0.000 claims description 13
- 238000005240 physical vapour deposition Methods 0.000 claims description 7
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 claims description 6
- 229910052710 silicon Inorganic materials 0.000 claims description 6
- 239000010703 silicon Substances 0.000 claims description 6
- 239000007769 metal material Substances 0.000 claims description 5
- 229910052581 Si3N4 Inorganic materials 0.000 claims description 4
- 238000001704 evaporation Methods 0.000 claims description 4
- 230000008020 evaporation Effects 0.000 claims description 4
- 229910021420 polycrystalline silicon Inorganic materials 0.000 claims description 4
- 229920005591 polysilicon Polymers 0.000 claims description 4
- HQVNEWCFYHHQES-UHFFFAOYSA-N silicon nitride Chemical compound N12[Si]34N5[Si]62N3[Si]51N64 HQVNEWCFYHHQES-UHFFFAOYSA-N 0.000 claims description 4
- KRHYYFGTRYWZRS-UHFFFAOYSA-N Fluorane Chemical compound F KRHYYFGTRYWZRS-UHFFFAOYSA-N 0.000 claims description 3
- 238000000151 deposition Methods 0.000 claims description 2
- 238000001312 dry etching Methods 0.000 claims description 2
- 229910000040 hydrogen fluoride Inorganic materials 0.000 claims description 2
- 238000005538 encapsulation Methods 0.000 claims 1
- 229920002120 photoresistant polymer Polymers 0.000 description 13
- 238000005516 engineering process Methods 0.000 description 8
- 239000003990 capacitor Substances 0.000 description 4
- 238000004891 communication Methods 0.000 description 4
- 239000007789 gas Substances 0.000 description 4
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- 238000010586 diagram Methods 0.000 description 3
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 2
- 230000015572 biosynthetic process Effects 0.000 description 2
- 238000011161 development Methods 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
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- 238000000206 photolithography Methods 0.000 description 2
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- 230000001133 acceleration Effects 0.000 description 1
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- 238000010276 construction Methods 0.000 description 1
- 238000005259 measurement Methods 0.000 description 1
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Classifications
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01C—MEASURING DISTANCES, LEVELS OR BEARINGS; SURVEYING; NAVIGATION; GYROSCOPIC INSTRUMENTS; PHOTOGRAMMETRY OR VIDEOGRAMMETRY
- G01C19/00—Gyroscopes; Turn-sensitive devices using vibrating masses; Turn-sensitive devices without moving masses; Measuring angular rate using gyroscopic effects
- G01C19/56—Turn-sensitive devices using vibrating masses, e.g. vibratory angular rate sensors based on Coriolis forces
- G01C19/5642—Turn-sensitive devices using vibrating masses, e.g. vibratory angular rate sensors based on Coriolis forces using vibrating bars or beams
- G01C19/5663—Manufacturing; Trimming; Mounting; Housings
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B81—MICROSTRUCTURAL TECHNOLOGY
- B81B—MICROSTRUCTURAL DEVICES OR SYSTEMS, e.g. MICROMECHANICAL DEVICES
- B81B7/00—Microstructural systems; Auxiliary parts of microstructural devices or systems
- B81B7/0032—Packages or encapsulation
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B81—MICROSTRUCTURAL TECHNOLOGY
- B81B—MICROSTRUCTURAL DEVICES OR SYSTEMS, e.g. MICROMECHANICAL DEVICES
- B81B7/00—Microstructural systems; Auxiliary parts of microstructural devices or systems
- B81B7/0032—Packages or encapsulation
- B81B7/0035—Packages or encapsulation for maintaining a controlled atmosphere inside of the chamber containing the MEMS
- B81B7/0041—Packages or encapsulation for maintaining a controlled atmosphere inside of the chamber containing the MEMS maintaining a controlled atmosphere with techniques not provided for in B81B7/0038
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B81—MICROSTRUCTURAL TECHNOLOGY
- B81B—MICROSTRUCTURAL DEVICES OR SYSTEMS, e.g. MICROMECHANICAL DEVICES
- B81B7/00—Microstructural systems; Auxiliary parts of microstructural devices or systems
- B81B7/02—Microstructural systems; Auxiliary parts of microstructural devices or systems containing distinct electrical or optical devices of particular relevance for their function, e.g. microelectro-mechanical systems [MEMS]
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B81—MICROSTRUCTURAL TECHNOLOGY
- B81C—PROCESSES OR APPARATUS SPECIALLY ADAPTED FOR THE MANUFACTURE OR TREATMENT OF MICROSTRUCTURAL DEVICES OR SYSTEMS
- B81C1/00—Manufacture or treatment of devices or systems in or on a substrate
- B81C1/00015—Manufacture or treatment of devices or systems in or on a substrate for manufacturing microsystems
- B81C1/00261—Processes for packaging MEMS devices
- B81C1/00269—Bonding of solid lids or wafers to the substrate
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B81—MICROSTRUCTURAL TECHNOLOGY
- B81C—PROCESSES OR APPARATUS SPECIALLY ADAPTED FOR THE MANUFACTURE OR TREATMENT OF MICROSTRUCTURAL DEVICES OR SYSTEMS
- B81C1/00—Manufacture or treatment of devices or systems in or on a substrate
- B81C1/00015—Manufacture or treatment of devices or systems in or on a substrate for manufacturing microsystems
- B81C1/00261—Processes for packaging MEMS devices
- B81C1/00277—Processes for packaging MEMS devices for maintaining a controlled atmosphere inside of the cavity containing the MEMS
- B81C1/00293—Processes for packaging MEMS devices for maintaining a controlled atmosphere inside of the cavity containing the MEMS maintaining a controlled atmosphere with processes not provided for in B81C1/00285
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01C—MEASURING DISTANCES, LEVELS OR BEARINGS; SURVEYING; NAVIGATION; GYROSCOPIC INSTRUMENTS; PHOTOGRAMMETRY OR VIDEOGRAMMETRY
- G01C19/00—Gyroscopes; Turn-sensitive devices using vibrating masses; Turn-sensitive devices without moving masses; Measuring angular rate using gyroscopic effects
- G01C19/56—Turn-sensitive devices using vibrating masses, e.g. vibratory angular rate sensors based on Coriolis forces
- G01C19/5776—Signal processing not specific to any of the devices covered by groups G01C19/5607 - G01C19/5719
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01C—MEASURING DISTANCES, LEVELS OR BEARINGS; SURVEYING; NAVIGATION; GYROSCOPIC INSTRUMENTS; PHOTOGRAMMETRY OR VIDEOGRAMMETRY
- G01C19/00—Gyroscopes; Turn-sensitive devices using vibrating masses; Turn-sensitive devices without moving masses; Measuring angular rate using gyroscopic effects
- G01C19/56—Turn-sensitive devices using vibrating masses, e.g. vibratory angular rate sensors based on Coriolis forces
- G01C19/5783—Mountings or housings not specific to any of the devices covered by groups G01C19/5607 - G01C19/5719
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- Engineering & Computer Science (AREA)
- Microelectronics & Electronic Packaging (AREA)
- Manufacturing & Machinery (AREA)
- Computer Hardware Design (AREA)
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Radar, Positioning & Navigation (AREA)
- Remote Sensing (AREA)
- Signal Processing (AREA)
- Micromachines (AREA)
Abstract
The invention provides an MEMS inertial integrated device and a preparation method thereof, wherein the preparation method comprises the following steps: the back of the cap wafer is sequentially provided with a sacrificial layer and a protective layer, the sacrificial layer comprises a central part and a radiation part, the radiation part comprises a plurality of radiation paths which are distributed in a radial manner by taking the central part as a center, and the front of the cap wafer is provided with an air suction hole which exposes part of the central part; etching the protective layer to form an opening, wherein the opening exposes part of the length of all the radiation paths far away from the central part side; the back layer is provided with the sacrificial layer to form an air guide hole in the protective layer between the opening and the air exhaust hole, the air guide hole is communicated with the air exhaust hole, and the radiation part hole of the air guide hole comprises a plurality of radiation road holes which are radially distributed by taking the central part hole as the center; and a sealing layer is formed on the protective layer, fills the opening and seals the air guide hole so as to seal the air suction holes with any aperture, and can seal all the air suction holes of the integrated wafer at one time during hole sealing, thereby improving the hole sealing efficiency and reducing the hole sealing cost.
Description
Technical Field
The invention relates to the technical field of inertia, in particular to an MEMS inertia integrated device and a preparation method thereof.
Background
The inertial technology is a core technology of navigation positioning, guidance control, stable aiming and image stabilization and attitude measurement, and the technical states of an inertial gyroscope and an accelerometer are the basis for representing the inertial technology. The gyroscope is used for measuring the angular velocity of the moving body, and the accelerometer is used for measuring the acceleration of the moving body. MEMS (Micro Electro MECHANICAL SYSTEM ) inertial devices refer to Micro mechanical gyroscopes and Micro accelerometers where sensitive structures are processed by micromachining means. MEMS inertial devices are widely used because of their small size, light weight, low power consumption, mass production, low cost, and strong overload resistance.
In the MEMS processing technology based on silicon, when integrating an inertial gyroscope and an accelerometer at a wafer level, as shown in fig. 1, after bonding a device wafer 1 and a cap wafer 2 is completed, air needs to be pumped from a pumping hole 3 for different vacuum degrees, and a laser hole sealing technology is adopted to seal each pumping hole 3 one by one (as shown in fig. 2), so as to realize the sealing of the pumping holes. The hole sealing process is only suitable for the air extraction holes with extremely small aperture (aperture is below 10 mu m), and the air extraction holes with larger aperture (aperture is more than 10 mu m) are difficult to seal; meanwhile, the efficiency of hole sealing one by one is low, and the productivity is affected. In addition, because the laser hole sealing needs a special machine, the machine is expensive, and when the aperture is changed, the machine needs to be modified, and the modification requirement is higher.
Disclosure of Invention
The invention aims to provide an MEMS inertial integrated device and a preparation method thereof, which can realize sealing of air extraction holes with any aperture, can realize sealing of all air extraction holes at one time during hole sealing, improve hole sealing efficiency and reduce hole sealing cost.
In order to solve the above problems, the present invention provides a method for manufacturing a MEMS inertial integrated device, comprising the steps of:
Bonding a cap wafer and a device wafer, wherein the cap wafer is provided with a front surface and a back surface which are oppositely arranged, the back surface is sequentially provided with a sacrificial layer and a protective layer, the sacrificial layer covers part of the back surface, the sacrificial layer comprises a central part and a radiation part, the radiation part is arranged on the outer side of the central part in a surrounding mode, the radiation part comprises a plurality of radiation paths which are distributed in a radial mode by taking the central part as a center, and the front surface is provided with air suction holes which expose part of the central part;
Etching the protective layer to form an opening, wherein the opening exposes part of the length of one side of all the radiation roads far away from the central part and also exposes part of the back surface between the adjacent radiation roads;
Removing the sacrificial layer to form an air guide hole in the protective layer between the opening and the air extraction hole, wherein the air guide hole is communicated with the air extraction hole, the air guide hole comprises a central part hole and a radiation part hole which are communicated, the radiation part hole is arranged on the outer side of the central part hole in a surrounding mode, and the radiation part hole comprises a plurality of radiation road holes which are distributed in a radial mode by taking the central part hole as a center; and
And forming a sealing layer on the protective layer, wherein the sealing layer fills the opening and seals the air guide hole.
Optionally, the central part is circular, and every the radiation road is rectangular form, just the one end connection of radiation road sets up the edge of central part.
Optionally, the cross section of the air pumping hole is circular, the air pumping hole and the central part are concentrically arranged, and the diameter of the air pumping hole is smaller than that of the central part.
Optionally, the opening is circular, and the centre of a circle of opening with the central part is concentric to be set up, just the inner ring of opening is greater than the diameter of central part, just be less than the diameter of central part with the length sum of radiation road, the outer loop of opening is greater than the diameter of central part with the length sum of radiation road.
Optionally, the method for removing the sacrificial layer includes:
And carrying out dry etching on the protective layer through gaseous hydrogen fluoride to remove the sacrificial layer exposed by the opening, removing the radiation road wrapped by the protective layer to form a plurality of radiation road holes, removing the central part to form a central part hole, wherein all the radiation road holes are communicated with the central part hole, and the central part hole is communicated with the air extraction hole, and the length of the radiation road hole is smaller than that of the radiation road.
Optionally, the method of forming the sealing layer includes:
and depositing a metal material on the protective layer through a PVD (physical vapor deposition) process or an evaporation process to form a sealing layer, wherein the sealing layer also fills the opening and seals the radiation road hole from the outer side.
Optionally, the protective layer is a polysilicon layer, a silicon nitride layer or a silicon epitaxial layer.
Optionally, the sacrificial layer is an oxide layer.
On the other hand, the invention also provides an MEMS inertia integrated device, which comprises a cap wafer and a device wafer which are arranged in a bonding way, wherein the cap wafer is provided with a front surface and a back surface which are oppositely arranged, the back surface is provided with a protection layer and a sealing layer, the protection layer is provided with an air vent close to the front surface side, an opening is annularly arranged on the outer side of the air vent on the protection layer, and the sealing layer covers the surface of the protection layer and the opening and seals the air vent;
The air guide holes comprise central holes and radiating part holes which are communicated, the radiating part holes are arranged on the outer sides of the central holes in a surrounding mode, the radiating part holes comprise a plurality of radiating road holes which are distributed in a radial mode by taking the central holes as centers, and air suction holes are formed in the front face of the air guide holes and are communicated with the central holes.
Optionally, the front surface is provided with a first bonding structure arranged at intervals with the air extraction holes, the bonding surface of the device wafer is provided with a second bonding structure, and the first bonding structure and the second bonding structure are opposite to each other.
Compared with the prior art, the invention has the following unexpected technical effects:
The invention provides an MEMS inertial integrated device and a preparation method thereof, wherein the preparation method comprises the following steps: bonding a cap wafer and a device wafer to form an integrated wafer, wherein the cap wafer is provided with a front surface and a back surface which are oppositely arranged, the back surface is sequentially provided with a sacrificial layer and a protective layer, the sacrificial layer covers part of the back surface, the sacrificial layer comprises a central part and a radiation part, the radiation part is arranged on the outer side of the central part in a surrounding manner, the radiation part comprises a plurality of radiation paths which are distributed in a radial manner by taking the central part as a center, the front surface is provided with air suction holes, and the air suction holes expose part of the central part; etching the protective layer to form an opening, wherein the opening exposes part of the length of one side of all the radiation roads far away from the central part and also exposes part of the back surface between the adjacent radiation roads; removing the sacrificial layer to form an air guide hole in the protective layer between the opening and the air extraction hole, wherein the air guide hole is communicated with the air extraction hole, the air guide hole comprises a central part hole and a radiation part hole which are communicated, the radiation part hole is arranged on the outer side of the central part hole in a surrounding mode, and the radiation part hole comprises a plurality of radiation road holes which are distributed in a radial mode by taking the central part hole as a center; and forming a sealing layer on the protective layer, wherein the sealing layer fills the opening and seals the air guide hole, so that sealing can be realized on all air suction holes with any aperture, and sealing can be realized on all air suction holes of the integrated wafer at one time during hole sealing, the hole sealing efficiency is improved, and the hole sealing cost is reduced.
Drawings
Fig. 1-2 are schematic structural diagrams related to hole sealing of a MEMS inertial integrated device in the prior art.
Fig. 3-13 are schematic structural diagrams of steps in a forming process of a MEMS inertial integrated device according to an embodiment of the present invention.
Fig. 14 is an enlarged schematic top view of block diagram a of fig. 11.
Reference numerals illustrate:
In fig. 1-2:
1-a device wafer; 2-capping the wafer; 3-an air pumping hole;
Fig. 3-14:
10-capping the wafer; 10 a-front side; 10 b-back side; 11-a sacrificial layer; 12-a protective layer; 13-a first bonding structure; 14-an initial air pumping hole; 15-a device receiving cavity; 16-an air pumping hole; 20-device wafer; 21-a comb differential capacitor structure; 22-a second bonding structure; 31-opening; 32-a closing layer.
Detailed Description
A MEMS inertial integrated device and method of making the same of the present invention will be described in further detail below. The present invention will be described in more detail below with reference to the attached drawings, in which preferred embodiments of the present invention are shown, it being understood that one skilled in the art can modify the present invention described herein while still achieving the advantageous effects of the present invention. Accordingly, the following description is to be construed as broadly known to those skilled in the art and not as limiting the invention.
In the interest of clarity, not all features of an actual implementation are described. In the following description, well-known functions or constructions are not described in detail since they would obscure the invention in unnecessary detail. It should be appreciated that in the development of any such actual embodiment, numerous implementation details must be made to achieve the developer's specific goals, such as compliance with system-related or business-related constraints, which will vary from one implementation to another. In addition, it will be appreciated that such a development effort might be complex and time-consuming, but would nevertheless be a routine undertaking for those of ordinary skill in the art.
In order to make the objects and features of the present invention more comprehensible, embodiments accompanied with figures are described in detail below. It is noted that the drawings are in a very simplified form and utilize non-precise ratios, and are intended to facilitate a convenient, clear, description of the embodiments of the invention.
The embodiment provides a preparation method of an MEMS inertial integrated device, which comprises the following steps:
step S1: bonding a cap wafer and a device wafer to form an integrated wafer, wherein the cap wafer is provided with a front surface and a back surface which are oppositely arranged, the back surface is sequentially provided with a sacrificial layer and a protective layer, the sacrificial layer covers part of the back surface, the sacrificial layer comprises a central part and a radiation part, the radiation part is arranged on the outer side of the central part in a surrounding mode, the radiation part comprises a plurality of radiation paths which are distributed in a radial mode by taking the central part as a center, the front surface is provided with air suction holes, and part of the central part is exposed by the air suction holes;
Step S2: etching the protective layer to form an opening, wherein the opening exposes part of the length of one side of all the radiation roads far away from the central part and also exposes part of the back surface between the adjacent radiation roads;
Step S3: removing the sacrificial layer to form an air guide hole in the protective layer between the opening and the air extraction hole, wherein the air guide hole is communicated with the air extraction hole, the air guide hole comprises a central part hole and a radiation part hole which are communicated, the radiation part hole is arranged on the outer side of the central part hole in a surrounding mode, and the radiation part hole comprises a plurality of radiation road holes which are distributed in a radial mode by taking the central part hole as a center;
step S4: and forming a sealing layer on the protective layer, wherein the sealing layer fills the opening and seals the air guide hole.
The following describes in detail a method for manufacturing a MEMS inertial integrated device according to this embodiment with reference to fig. 3 to 14.
Step S1 is first performed to bond a cap wafer 10 and a device wafer 20 to form an integrated wafer, where the cap wafer 10 has a front surface 10a and a back surface 10b that are disposed opposite to each other, the back surface 10b is sequentially provided with a sacrificial layer 11 and a protective layer 12, the sacrificial layer 11 covers a portion of the back surface 10b, the sacrificial layer 11 includes a central portion and a radiation portion, the radiation portion is disposed around the outside of the central portion, the radiation portion includes a plurality of radiation paths radially distributed with the central portion as a center, the front surface 10a is provided with an air extraction hole 16, and the air extraction hole 16 exposes a portion of the central portion.
The method specifically comprises the following steps:
As shown in fig. 3, first, a cap wafer 10 is provided, and the cap wafer 10 may be a double polished silicon wafer. The cap wafer 10 has a front surface 10a and a back surface 10b disposed opposite to each other, the back surface 10b is deposited with a sacrificial layer 11, the sacrificial layer 11 covers the back surface 10b, and the sacrificial layer 11 serves as an etching stop layer for the subsequent pumping holes 16. The cap wafer 10 includes a plurality of first chips distributed in an array.
Wherein the sacrificial layer 11 may be an oxide layer, such as a silicon dioxide layer.
Referring to fig. 4, referring to fig. 14, the sacrificial layer 11 is patterned by photolithography and etching processes. The sacrificial layer 11 on each first chip includes a central portion and a radiation portion, the radiation portion being disposed around the outside of the central portion, the radiation portion including a plurality of radiation paths radially distributed centering on the central portion. The central portion may be in a regular pattern, such as a regular pattern of circles, squares, ovals, etc., preferably the central portion is circular. The center portion serves as an etch stop layer for the subsequent etching to form the gas vent 16, and its dimensions may vary as the aperture of the gas vent 16 varies.
All the radiation roads are uniformly arranged outside the central part, each radiation road is long-strip-shaped, and one end of each radiation road is connected and arranged at the edge of the central part.
As shown in fig. 5, next, a protective layer 12 is deposited on the sacrificial layer 11, the protective layer 12 covering the back surface 10b. The protective layer 12 may be a polysilicon layer, a silicon nitride layer, a silicon epitaxial layer, or the like. The protective layer 12 may protect the sacrificial layer 11 in a subsequent process.
As shown in fig. 6, a first bonding structure 13 is then formed on the front surface 10 a. In detail, a bonding metal material layer is deposited on the front surface 10a, a first photoresist layer is formed, the first photoresist layer is aligned by infrared rays to form a patterned first photoresist layer, the bonding metal material layer is etched by using the patterned first photoresist layer as a mask to form the first bonding structure 13, and finally the first photoresist layer is removed.
As shown in fig. 7, a patterned second photoresist layer is formed on the front surface 10a, the patterned second photoresist layer exposes a portion of the front surface 10a, and the second photoresist layer defines the shapes of the pumping holes 16 and the device accommodating cavities 15, and then the front surface 10a is etched with the patterned second photoresist layer as a mask to form the initial pumping holes 14 and the device accommodating cavities 15, wherein the bottoms of the initial pumping holes 14 are located between the front surface 10a and the back surface 10b of the cap wafer 10, that is, the bottoms of the initial pumping holes 14 are located in the cap wafer 10, and the bottoms of the device accommodating cavities 15 are also located between the front surface 10a and the back surface 10b of the cap wafer 10, that is, the bottoms of the device accommodating cavities 15 are located in the cap wafer 10. Wherein a first bonding structure is provided outside the initial pumping hole 14 and the device receiving cavity 15 and on the front surface 10a of the device receiving cavity 15 adjacent thereto, which is not provided between the initial pumping hole 14 and the device receiving cavity 15. And finally, removing the second photoresist layer.
Next, an accelerometer device and a gyro integrated device are formed in the device housing cavity 15. In this embodiment, two device accommodating chambers 15 are provided in each first chip, the two device accommodating chambers 15 are provided at intervals, an accelerometer device is formed in one of the device accommodating chambers 15, and a gyro integrated device is formed in the other device accommodating chamber 15.
Next, as shown in fig. 8, a patterned third photoresist layer is formed on the front surface 10a, the patterned third photoresist layer exposes the initial pumping holes 14, and the patterned third photoresist layer is used as a mask to etch the initial pumping holes 14, so as to expose a portion of the central portion and form pumping holes 16.
Wherein, the projection of the air pumping hole 16 on the plane of the sacrificial layer 11 is positioned in the center part. The cross section of the air extraction hole 16 may be circular or rectangular, in this embodiment, the cross section of the air extraction hole 16 is circular, the air extraction hole 16 is concentric with the central portion, and the diameter of the air extraction hole 16 is smaller than the diameter of the central portion.
As shown in fig. 9, a device wafer 20 is then provided, the device wafer 20 has the same size as the cap wafer 10, and the device wafer 20 includes a plurality of second chips distributed in an array. The device wafer 20 has a bonding surface, and a second bonding structure 22 and a comb differential capacitor structure 21 are disposed on the bonding surface at intervals.
As shown in fig. 10, the cap wafer 10 and a device wafer 20 are then bonded to form an integrated wafer, the front surface 10a faces the bonding surface, such that the first bonding structure 13 is disposed toward the second bonding structure 22, and the first bonding structure 13 is disposed opposite to the second bonding structure 22, so as to bond the first chip and the second chip. In the bonding structure of the first chip and the second chip, the first bonding structure 13 is connected with the second bonding structure 22, and the air pumping hole 16 is communicated with the device accommodating cavity 15 and the comb-tooth differential capacitor structure 21. The bonding process of this step employs a vacuum pressure control process and is the same as the bonding process without the gas vent 16.
As shown in fig. 11, referring to fig. 14, step S2 is performed to etch all the protection layers 12 to form openings 31, wherein the openings 31 expose a portion of the length of the side of the radiation path away from the center portion, and also expose a portion of the back surface 10b between the radiation paths.
The method specifically comprises the following steps: the protection layer 12 is etched by a photolithography and etching process to form an annular (e.g., circular) opening 31, the center of the opening 31 is concentric with the center portion, the inner ring of the opening 31 is larger than the diameter of the center portion and smaller than the sum of the diameter of the center portion and the length of the radiation path, and the outer ring of the opening 31 is larger than the sum of the diameter of the center portion and the length of the radiation path, so that the opening 31 exposes a part of the radiation path and simultaneously exposes a part of the back surface 10b between the radiation paths.
As shown in fig. 12, step S3 is performed to remove the sacrificial layer 11, so as to form a plurality of air guide holes in the protective layer 12 between the opening 31 and the air extraction hole 16, wherein the air guide holes are communicated with the air extraction hole 16, the air guide holes include a central hole and a radiation hole, which are disposed in a communicating manner, the radiation hole is surrounded on the outer side of the central hole, and the radiation hole includes a plurality of radiation road holes distributed radially with the central hole as a center.
The method specifically comprises the following steps: the protective layer 12 is dry etched by gaseous Hydrogen Fluoride (HF) to remove the sacrificial layer 11 exposed by the opening 31, remove the radiation path covered by the protective layer 12 to form a radiation path hole having the same shape and the same number as the sacrificial layer 11, and remove the central portion to form a central portion hole, all of which are in communication with the central portion hole, and the central portion hole is in communication with the pumping hole 16, so that the pumping hole 16 is in communication with the outside through the gas-guide hole. Therefore, the air guide hole comprises a central hole and a radiation part hole which are communicated, the radiation part hole is surrounded on the outer side of the central hole, and the radiation part hole comprises a plurality of radiation road holes which are distributed in a radial mode by taking the central hole as a center. It is known that the length of the radiation portion hole is smaller than the length of the radiation path of the sacrificial layer 11.
As shown in fig. 13, step S4 is performed, and a sealing layer 32 is formed on the protective layer 12, where the sealing layer 32 fills the opening 31 and seals the air vent.
The method specifically comprises the following steps: a metal material is deposited on the protective layer 12 by PVD (physical vapor deposition ) process or evaporation process to form a closing layer 32, the closing layer 32 also filling the opening 31 and blocking the radiation passage hole from outside. Because both the PVD process and the evaporation process are performed in a vacuum environment, before the formation of the sealing layer 32, the gases in the device accommodating cavity 15 and the comb differential capacitor structure 21 are all extracted through the radiation path holes, which makes no special air extraction process necessary, and because of the formation of the sealing layer 32, vacuum sealing is realized on all the air extraction holes 16 on the integrated wafer at one time, so that the efficiency is improved, and the sealing is not required to be performed in special equipment (i.e. a laser sealing machine in the prior art), so that the requirement of the sealing process on the special equipment is reduced, and the cost is reduced. In addition, the size of the air extraction hole can be designed according to actual demands, and the dilemma that hole sealing cannot be performed is avoided, so that the problem of filling and sealing of the air extraction hole with a larger aperture is solved.
As shown in fig. 2-14, this embodiment further provides a MEMS inertial integrated device, including a cap wafer 10 and a device wafer 20 that are bonded together, where the cap wafer 10 has a front surface 10a and a back surface 10b that are disposed opposite to each other, the back surface 10b is provided with a protection layer 12 and a sealing layer 32, the protection layer 12 has an air vent on a side close to the front surface 10a, an opening 31 is disposed around the protection layer 12 outside the air vent, the sealing layer 32 covers the surface of the protection layer 12 and the opening 31, and seals the air vent, the air vent includes a central hole and a radiation hole that are disposed in communication, the radiation hole is disposed around the outside of the central hole, the radiation hole includes a plurality of radiation path holes that are radially distributed with the central hole as a center, the front surface 10a is provided with an air suction hole 16, and the air suction hole 16 is communicated with the central hole. The front surface 10a is provided with a first bonding structure 13 spaced from the air extraction hole 16, a second bonding structure 22 is formed on the bonding surface of the device wafer 20, and the first bonding structure 13 and the second bonding structure 22 are opposite to each other.
The protective layer 12 may be a polysilicon layer, a silicon nitride layer, a silicon epitaxial layer, or the like. The central aperture may be in a regular pattern, such as a regular pattern of circles, squares, ovals, etc., preferably the central aperture is a circular aperture. The central hole is arranged concentrically with the suction hole 16, and the diameter of the central hole is larger than the diameter of the suction hole 16.
In summary, the present invention provides a MEMS inertial integrated device and a method for manufacturing the same, the method for manufacturing the same comprising the steps of: bonding a cap wafer and a device wafer to form an integrated wafer, wherein the cap wafer is provided with a front surface and a back surface which are oppositely arranged, the back surface is sequentially provided with a sacrificial layer and a protective layer, the sacrificial layer covers part of the back surface, the sacrificial layer comprises a central part and a radiation part, the radiation part is arranged on the outer side of the central part in a surrounding manner, the radiation part comprises a plurality of radiation paths which are distributed in a radial manner by taking the central part as a center, the front surface is provided with air suction holes, and the air suction holes expose part of the central part; etching the protective layer to form an opening, wherein the opening exposes part of the length of one side of all the radiation roads far away from the central part and also exposes part of the back surface between the adjacent radiation roads; removing the sacrificial layer to form an air guide hole in the protective layer between the opening and the air extraction hole, wherein the air guide hole is communicated with the air extraction hole, the air guide hole comprises a central part hole and a radiation part hole which are communicated, the radiation part hole is arranged on the outer side of the central part hole in a surrounding mode, and the radiation part hole comprises a plurality of radiation road holes which are distributed in a radial mode by taking the central part hole as a center; and forming a sealing layer on the protective layer, wherein the sealing layer fills the opening and seals the air guide hole, so that sealing can be realized on all air suction holes with any aperture, and sealing can be realized on all air suction holes of the integrated wafer at one time during hole sealing, the hole sealing efficiency is improved, and the hole sealing cost is reduced.
Furthermore, unless specifically stated or indicated otherwise, the description of the terms "first," "second," and the like in the specification merely serve to distinguish between various components, elements, steps, etc. in the specification, and do not necessarily represent a logical or sequential relationship between various components, elements, steps, etc.
It will be appreciated that although the invention has been described above in terms of preferred embodiments, the above embodiments are not intended to limit the invention. Many possible variations and modifications of the disclosed technology can be made by anyone skilled in the art without departing from the scope of the technology, or the technology can be modified to be equivalent. Therefore, any simple modification, equivalent variation and modification of the above embodiments according to the technical substance of the present invention still fall within the scope of the technical solution of the present invention.
Claims (10)
1. The preparation method of the MEMS inertial integrated device is characterized by comprising the following steps of:
Bonding a cap wafer and a device wafer to form an integrated wafer, wherein the cap wafer is provided with a front surface and a back surface which are oppositely arranged, the back surface is sequentially provided with a sacrificial layer and a protective layer, the sacrificial layer covers part of the back surface, the sacrificial layer comprises a central part and a radiation part, the radiation part is arranged on the outer side of the central part in a surrounding manner, the radiation part comprises a plurality of radiation paths which are distributed in a radial manner by taking the central part as a center, the front surface is provided with air suction holes, and the air suction holes expose part of the central part;
Etching the protective layer to form an opening, wherein the opening exposes part of the length of one side of all the radiation roads far away from the central part and also exposes part of the back surface between the adjacent radiation roads;
Removing the sacrificial layer to form an air guide hole in the protective layer between the opening and the air extraction hole, wherein the air guide hole is communicated with the air extraction hole, the air guide hole comprises a central part hole and a radiation part hole which are communicated, the radiation part hole is arranged on the outer side of the central part hole in a surrounding mode, and the radiation part hole comprises a plurality of radiation road holes which are distributed in a radial mode by taking the central part hole as a center; and
And forming a sealing layer on the protective layer, wherein the sealing layer fills the opening and seals the air guide hole.
2. The method of manufacturing a MEMS inertial integrated device according to claim 1, wherein the center portion is circular, each of the radiation paths is elongated, and one end of the radiation path is connected to and disposed at an edge of the center portion.
3. The method of manufacturing a MEMS inertial integrated device according to claim 1, wherein the suction hole has a circular cross section, the suction hole is disposed concentrically with the center portion, and a diameter of the suction hole is smaller than a diameter of the center portion.
4. The method of manufacturing a MEMS inertial integrated device according to claim 1, wherein the opening is annular, a center of the opening is concentric with the center portion, an inner ring of the opening is larger than a diameter of the center portion and smaller than a sum of the diameter of the center portion and a length of the radiation path, and an outer ring of the opening is larger than a sum of the diameter of the center portion and the length of the radiation path.
5. The method of fabricating a MEMS inertial integrated device according to claim 1, wherein the removing the sacrificial layer comprises:
And carrying out dry etching on the protective layer through gaseous hydrogen fluoride to remove the sacrificial layer exposed by the opening, removing the radiation road wrapped by the protective layer to form a plurality of radiation road holes, removing the central part to form a central part hole, wherein all the radiation road holes are communicated with the central part hole, and the central part hole is communicated with the air extraction hole, and the length of the radiation road hole is smaller than that of the radiation road.
6. The method of fabricating a MEMS inertial integrated device according to claim 1, wherein the method of forming the encapsulation layer comprises:
and depositing a metal material on the protective layer through a PVD (physical vapor deposition) process or an evaporation process to form a sealing layer, wherein the sealing layer also fills the opening and seals the radiation road hole from the outer side.
7. The method for manufacturing a MEMS inertial integrated device according to any one of claims 1 to 6, wherein the protective layer is a polysilicon layer, a silicon nitride layer or a silicon epitaxial layer.
8. The method for manufacturing a MEMS inertial integrated device according to any one of claims 1 to 6, wherein the sacrificial layer is an oxide layer.
9. The MEMS inertial integrated device is characterized by comprising a cap wafer and a device wafer which are arranged in a bonding way, wherein the cap wafer is provided with a front surface and a back surface which are oppositely arranged, the back surface is provided with a protection layer and a sealing layer, the protection layer is provided with an air vent close to the front surface side, an opening is annularly arranged on the outer side of the air vent on the protection layer, and the sealing layer covers the surface of the protection layer and the opening and seals the air vent;
The air guide holes comprise central holes and radiating part holes which are communicated, the radiating part holes are arranged on the outer sides of the central holes in a surrounding mode, the radiating part holes comprise a plurality of radiating road holes which are distributed in a radial mode by taking the central holes as centers, and air suction holes are formed in the front face of the air guide holes and are communicated with the central holes.
10. The MEMS inertial integrated device of claim 9, wherein the pumping aperture is circular in cross-section, the central aperture is a circular aperture, the central aperture is concentric with the pumping aperture, and a diameter of the central aperture is greater than a diameter of the pumping aperture.
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