Bone conduction MEMS chip and manufacturing method therefor, and bone conduction packaging structure having bone conduction MEMS chip

Abstract

The present invention provides a bone conduction MEMS chip and a manufacturing method therefor, and a bone conduction packaging structure having the bone conduction MEMS chip. The bone conduction MEMS chip comprises: a substrate provided with a cavity, a diaphragm supported on the substrate, and a back plate spaced apart from the side of the diaphragm distant from the substrate, wherein a mass block is arranged on the side of the diaphragm distant from the back plate. The mass block in the bone conduction MEMS chip of the present invention is directly formed on the diaphragm, and the bone conduction packaging structure avoids additionally providing a vibration sheet and a mass block, thereby reducing costs, achieving simple packaging, and allowing the structure to be smaller.

Description

Bone conduction MEMS chip and its manufacturing method, and bone conduction packaging structure having the bone conduction MEMS chip. Technical Field

[0001] This invention relates to the field of acoustic-to-electric conversion, and more particularly to a bone conduction MEMS chip and its manufacturing method, as well as a bone conduction packaging structure having the bone conduction MEMS chip. Background Technology

[0002] Bone conduction microphones convert the slight vibrations of the head and neck bones caused by a person speaking into electrical signals. Unlike traditional microphones that collect sound through air conduction, they can reproduce sound with high clarity even in noisy environments, thus avoiding noise interference caused by sound transmission through the air and ensuring extremely high sound quality. Technical issues

[0003] In related technologies, bone conduction packaging structures include a housing, a circuit board enclosing a receiving space with the housing, a vibration component disposed within the receiving space, and a MEMS chip. The vibration component includes a vibrating plate opposite to and spaced from the circuit board, a frame connecting the vibrating component and the circuit board, and a mass block disposed on the vibration component. When the bone conduction packaging structure is working, the housing receives a vibration signal or pressure signal. The vibrating plate and the mass block are excited by the vibration signal or pressure signal, causing them to vibrate. This causes the gas in the receiving space to vibrate, resulting in a change in air pressure within the receiving space. The MEMS detects this change in air pressure and converts the sensed information into a detectable electrical signal, which is then transmitted to the circuit board. However, the bone conduction packaging structures of related technologies are relatively large, and the structure of the vibration component within the bone conduction packaging structure is complex, costly, and difficult to adjust in terms of sensitivity.

[0004] Therefore, it is necessary to provide a new bone conduction encapsulation structure to solve the above-mentioned technical problems. Technical solutions

[0005] The purpose of this invention is to provide a bone conduction MEMS chip with high sensitivity.

[0006] To achieve the above objectives, the technical solution of the present invention is as follows: a bone conduction MEMS chip, the bone conduction MEMS chip comprising: a substrate having a cavity, a diaphragm supported on the substrate, and a back plate spaced apart on the side of the diaphragm away from the substrate, wherein a mass block is disposed on the side of the diaphragm away from the back plate.

[0007] Preferably, the bone conduction MEMS chip further includes a connecting post that connects the mass block to the side of the diaphragm away from the backplate.

[0008] Preferably, the mass block is located in the cavity, and the mass block and the substrate are made of the same material.

[0009] Compared with related technologies, the bone conduction MEMS chip provided by this invention includes: a substrate with a cavity, a diaphragm supported on the substrate, and a backplate spaced apart on the side of the diaphragm away from the substrate. A mass block is disposed on the side of the diaphragm away from the backplate. This invention, by directly disposing of a mass block on the diaphragm of the bone conduction MEMS chip, allows the sensitivity of the bone conduction MEMS chip to be flexibly adjusted by directly adjusting the size of the mass block, thus offering strong practicality.

[0010] Another objective of this invention is a method for fabricating a highly sensitive bone conduction MEMS chip.

[0011] To achieve the above objectives, the technical solution of the present invention is as follows: a method for manufacturing a bone conduction MEMS chip, the method comprising the following steps:

[0012] Provide substrate;

[0013] A first silicon oxide layer is deposited on a substrate, and the first silicon oxide layer is etched to form a groove on the first silicon oxide layer extending to the surface of the substrate;

[0014] A polysilicon layer is deposited to cover the first silicon oxide layer, and a portion of the polysilicon layer extends into the groove to form a connecting post. The polysilicon layer on the surface of the first silicon oxide layer is patterned to form a diaphragm, and the diaphragm is connected to the connecting post.

[0015] A second silicon oxide layer is deposited on the surface of the diaphragm;

[0016] A backplane material layer is deposited on the surface of the second silicon oxide layer, and the backplane material layer is etched to form several through holes;

[0017] The substrate is reverse etched to form a cavity and a mass block connected to the diaphragm, and the first silicon oxide layer under the diaphragm is etched.

[0018] The second silicon oxide layer above the diaphragm is etched through the via to release the diaphragm.

[0019] Preferably, when patterning the polycrystalline silicon layer on the surface of the first silicon oxide layer to form a diaphragm, it includes forming perforations on the diaphragm.

[0020] Preferably, a backplane material layer is deposited on the surface of the second silicon oxide layer, including depositing a backplane electrode material layer and etching the backplane electrode material layer to form a backplane electrode, depositing a silicon nitride layer on the backplane electrode and patterning the silicon nitride layer to form a backplane.

[0021] Preferably, a second silicon oxide layer is deposited on the surface of the diaphragm, including etching the second silicon oxide layer to form a first recess;

[0022] A back plate electrode material layer is deposited and etched to form a back plate electrode, including forming a second recess on the back plate electrode aligned with the first recess;

[0023] A silicon nitride layer is deposited on the back plate electrode and patterned to form a back plate, including the back plate forming a protruding portion accommodated in the first recess and the second recess.

[0024] Preferably, the substrate is etched in reverse to form a cavity and a mass block connected to the diaphragm, including twice etching, the first time etching the substrate to form a partial cavity, and the second time etching to form a mass block connected to the diaphragm.

[0025] Preferably, after forming the mass block, the first silicon oxide layer under the diaphragm is etched. Advantages

[0026] Compared with the related art, the manufacturing method of the bone conduction MEMS chip provided by the present application includes the following steps: providing a substrate; depositing a first silicon oxide layer on the substrate, etching the first silicon oxide layer to form a groove extending to the surface of the substrate on the first silicon oxide layer; depositing a polysilicon layer covering the first silicon oxide layer, the polysilicon layer partially extending into the groove to form a connecting column, and patterning the polysilicon layer on the surface of the first silicon oxide layer to form a diaphragm connected to the connecting column; depositing a second silicon oxide layer on the surface of the diaphragm; depositing a back plate material layer on the surface of the second silicon oxide layer, etching the back plate material layer to form a plurality of through holes; etching the substrate in reverse to form a cavity and a mass block connected to the diaphragm, and etching the first silicon oxide layer under the diaphragm; and etching the second silicon oxide layer above the diaphragm through the through holes to release the diaphragm. The present application directly sets a mass block on the diaphragm of the bone conduction MEMS chip, so that the sensitivity of the bone conduction MEMS chip can be flexibly adjusted by directly adjusting the size of the mass block, and the practicality is strong.

[0027] The present application aims to provide a bone conduction packaging structure which is small in size, low in cost and simple in structure.

[0028] In order to achieve the above object, the technical scheme of the present application is as follows: the bone conduction packaging structure comprises a substrate, a shell which covers the substrate to form a containing space, a bone conduction MEMS chip and an ASIC chip arranged in the containing space, the bone conduction MEMS chip is the bone conduction MEMS chip of claim 1, and the bone conduction MEMS chip is the bone conduction MEMS chip described above.

[0029] Compared with the related art, the bone conduction packaging structure provided by the present application directly arranges the mass on the diaphragm of the bone conduction MEMS chip, avoids arranging the vibrating plate and the mass in the bone conduction packaging structure, reduces the cost, simplifies the packaging, and makes the structure smaller. BRIEF DESCRIPTION OF DRAWINGS

[0030] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings needed to be used in the embodiment description will be briefly introduced as follows. Obviously, the drawings in the following description are only some embodiments of the present application, and for those skilled in the art, other drawings can be obtained without creative labor based on these drawings.

[0031] Fig. 1 is a schematic diagram of the three-dimensional structure of the bone conduction MEMS chip of the present application;

[0032] Fig. 2 is a sectional view of the bone conduction packaging structure of the present application;

[0033] Figs. 3a to 3h are a flowchart of the manufacturing process of the bone conduction MEMS chip as shown in Fig. 1. Best mode of the present application

[0034] The technical solutions in the embodiments of the present application will be described clearly and completely in combination with the drawings of the embodiments of the present application. Obviously, the described embodiments are only some of the embodiments of the present application, but not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor are within the scope of protection of the present application.

[0035] Please refer to Figs. 1 and 2, the present application provides a bone conduction packaging structure 100, which comprises a substrate 1, a shell 2 which covers the substrate 1 to form a containing space 10, a bone conduction MEMS chip 3 and an ASIC chip 4 arranged in the containing space 10.

[0036] The substrate 1 is a circuit board, and the shell 2 can be a metal shell.

[0037] The bone conduction MEMS chip 3 comprises a substrate 31 with a cavity 310, a diaphragm 32 supported on the substrate 31, and a back plate 33 arranged apart from the diaphragm 32 away from the substrate 31, and a mass 34 arranged on the side of the diaphragm 32 away from the back plate 33. The mass 34 and the substrate 31 are made of the same material, and the bone conduction MEMS chip 3 further comprises a connecting column 35 connecting the mass 34 to the side of the diaphragm 32 away from the back plate 33, and the mass 34 is located in the cavity 310. The mass 34 is directly arranged on the diaphragm 32 of the bone conduction MEMS chip 3, so that the sensitivity of the bone conduction MEMS chip 3 can be flexibly adjusted by directly adjusting the size of the mass 34, and the practicability is high. Meanwhile, the bone conduction packaging structure 100 avoids arranging the diaphragm and the mass in the accommodation space 10, reduces the cost, and is simple to package and has a smaller structure.

[0038] Referring to FIGS. 3a-3h, the application further provides a manufacturing method of the bone conduction MEMS chip 3, and the manufacturing method of the bone conduction MEMS chip 3 comprises the following steps:

[0039] A substrate material 101 is provided to form a substrate 31.

[0040] A first silicon oxide layer 102 is deposited on the substrate 31, and the first silicon oxide layer 102 is etched to form a plurality of grooves 103 extending to the surface of the substrate 31 on the first silicon oxide layer 102.

[0041] A polysilicon layer 104 is deposited to cover the first silicon oxide layer 102, the polysilicon layer 104 partially extends into the grooves 103 to form connecting columns 35, the polysilicon layer 104 on the surface of the first silicon oxide layer 102 is patterned to form a diaphragm 32, a through hole 321 is formed on the diaphragm 32, and the diaphragm 32 is connected with the connecting columns 35.

[0042] A second silicon oxide layer 105 is deposited on the surface of the diaphragm 32, and a plurality of first recesses 1051 are formed by etching the second silicon oxide layer 105.

[0043] A backplate material layer 106 is deposited on the surface of the second silicon oxide layer 105, and the backplate material layer 106 is etched to form a plurality of through holes 1061. The backplate material layer 106 includes a backplate electrode material 1062 and a silicon nitride layer 1064. The deposition of the backplate material layer 106 specifically includes depositing the backplate electrode material layer 1062 on the second silicon oxide layer 105 and etching the backplate electrode material layer 1062 to form a backplate electrode 1063. A second recess 1065 is formed on the backplate electrode 1063 and is aligned with the first recess 1051. The silicon nitride layer 1064 is then deposited on the backplate electrode 1063 and is patterned to form a backplate 33. The silicon nitride layer 1064 fills the first recess 1051 and the second recess 1065, so that the backplate 33 forms a protruding portion 1066 accommodated in the first recess 1051 and the second recess 1065.

[0044] The substrate 31 is etched in reverse to form a cavity 310 and a mass 34 connected to the diaphragm 32, and the first silicon oxide layer 102 under the diaphragm 32 is etched. This step specifically includes: first, forming the cavity 310 and the mass 34 by etching twice. Specifically, the substrate 31 is etched once to form part of the cavity 310. At this time, the remaining thickness of the substrate 31 is the thickness of the mass 34, which can be adjusted according to requirements at this time. The mass 34 is etched a second time to form the mass 34 connected to the diaphragm 32. The mass 34 is located at the middle position of the diaphragm 32. After the mass 34 is formed, the first silicon oxide layer 102 under the diaphragm 32 is etched.

[0045] The diaphragm 32 is released by etching the second silicon oxide layer 106 above the diaphragm 32 through the through holes 1061. In this way, the diaphragm 32 will have complete space for up and down vibration.

[0046] The diaphragm 32 of the bone conduction MEMS chip 3 is supported on the substrate 31 by the connecting columns 35 and part of the first silicon oxide layer 102. The part of the first silicon oxide layer 102 is the first silicon oxide layer 102 between adjacent connecting columns 35 and the first silicon oxide layer 102 between the connecting columns 35 and the backplate 33. The mass 34 is also connected to the diaphragm 32 by the connecting columns 35 and part of the first silicon oxide layer 102. The part of the first silicon oxide layer 102 is the first silicon oxide layer 102 between adjacent connecting columns 35 in the central region of the diaphragm 32.

[0047] The protruding portion 1066 on the backplate 33 can prevent the diaphragm 32 from sticking to the backplate 33 when the diaphragm 32 vibrates.

[0048] Compared with the related art, the bone conduction MEMS chip provided by the application comprises a substrate with a cavity, a diaphragm supported on the substrate, and a back plate arranged at a side of the diaphragm away from the substrate, and a mass is arranged at a side of the diaphragm away from the back plate.

[0049] Compared with the prior art, the mass is directly formed on the diaphragm of the bone conduction MEMS chip by twice etching, and the thickness and size of the mass can be flexibly adjusted, so that the sensitivity of the bone conduction MEMS chip can be flexibly adjusted by directly adjusting the size of the mass, and the practicability is high.

[0050] Compared with the related art, the bone conduction packaging structure provided by the application directly arranges the mass on the diaphragm of the bone conduction MEMS chip, avoids arranging the diaphragm and the mass in the bone conduction packaging structure additionally, reduces the cost, is simple in packaging, and can have a smaller structure.

[0051] The above only describes the embodiments of the application, and it should be noted that, for those skilled in the art, improvements can be made without departing from the inventive concept, and these all belong to the protection scope of the application.

Claims

1. A bone conduction MEMS chip, characterized by, The bone conduction MEMS chip comprises a substrate with a cavity, a diaphragm supported on the substrate, and a back plate spaced apart from the diaphragm away from the substrate, and a mass block arranged on the side of the diaphragm away from the back plate.

2. The bone conduction MEMS chip of claim 1, wherein, The bone conduction MEMS chip further comprises a connecting column connecting the mass block to the side of the diaphragm away from the back plate.

3. The bone conduction MEMS chip of claim 1, wherein, The mass block is located in the cavity, and the mass block and the substrate are made of the same material.

4. A method of manufacturing a bone conduction MEMS chip, characterized by, The manufacturing method of the bone conduction MEMS chip comprises the following steps: providing a substrate; depositing a first silicon oxide layer on the substrate, etching the first silicon oxide layer to form a groove extending to the surface of the substrate on the first silicon oxide layer; depositing a polysilicon layer covering the first silicon oxide layer, the polysilicon layer partially extending into the groove to form a connecting column, and patterning the polysilicon layer on the surface of the first silicon oxide layer to form a diaphragm connected with the connecting column; depositing a second silicon oxide layer on the surface of the diaphragm; depositing a back plate material layer on the surface of the second silicon oxide layer, and etching the back plate material layer to form a plurality of through holes; reverse etching the substrate to form a cavity and a mass block connected to the diaphragm, and etching the first silicon oxide layer under the diaphragm; etching the second silicon oxide layer above the diaphragm through the through holes to release the diaphragm.

5. The manufacturing method of the bone conduction MEMS chip according to claim 4, wherein when patterning the polysilicon layer on the surface of the first silicon oxide layer to form a diaphragm, a through hole is formed on the diaphragm.

6. The manufacturing method of the bone conduction MEMS chip according to claim 4, wherein depositing a back plate material layer on the surface of the second silicon oxide layer comprises depositing a back plate electrode material layer and etching the back plate electrode material layer to form a back plate electrode, depositing a silicon nitride layer on the back plate electrode and patterning the silicon nitride layer to form a back plate.

7. The manufacturing method of the bone conduction MEMS chip according to claim 6, wherein depositing a second silicon oxide layer on the surface of the diaphragm comprises etching the second silicon oxide layer to form a first recess; depositing a back plate electrode material layer and etching the back plate electrode material layer to form a back plate electrode comprises forming a second recess on the back plate electrode aligned with the first recess; depositing a silicon nitride layer on the back plate electrode and patterning the silicon nitride layer to form a back plate comprises forming a protruding part of the back plate accommodated in the first recess and the second recess.

8. The manufacturing method of the bone conduction MEMS chip according to claim 4, wherein reverse etching the substrate to form a cavity and a mass block connected to the diaphragm comprises twice etching, first etching the substrate to form a partial cavity, and second etching to form a mass block connected to the diaphragm.

9. The manufacturing method of the bone conduction MEMS chip according to claim 8, wherein after forming the mass block, etching the first silicon oxide layer under the diaphragm.

10. A bone conduction package structure, characterized in that, The bone conduction packaging structure comprises a substrate, a shell forming a containing space with the substrate cover, a bone conduction MEMS chip and an ASIC chip arranged in the containing space, and the bone conduction MEMS chip is the bone conduction MEMS chip according to claim 1.

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