CN102457800A

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Info

Publication number: CN102457800A
Application number: CN2010105144148A
Authority: CN
Inventors: 杨少军
Original assignee: BEIJING ACUTI MICROSYSTEMS Co Ltd
Current assignee: BEIJING ACUTI MICROSYSTEMS Co Ltd
Priority date: 2010-10-21
Filing date: 2010-10-21
Publication date: 2012-05-16

Abstract

The invention discloses an MEMS (Micro Electronic Mechanical System) capacitive microphone without a back polar plate and a manufacture method thereof. The MEMS capacitive microphone comprises a substrate, a back cavity, a first polar plate of a capacitor, a second polar plate of the capacitor, a vibration diaphragm and leads, wherein the back cavity is positioned on the substrate; the vibration diaphragm is arranged on the substrate and is used for detecting acoustical vibration and converting the acoustical vibration into displacement; the first polar plate is arranged on the substrate; the second polar plate is arranged on the vibration diaphragm and is provided with bulges which are used for preventing the first polar plate and the second polar plate from being mutually sucked; and the leads are used for leading out the first polar plate and the second polar plate so as to form electric connection.

Description

MEMS Electret Condencer Microphone of backplateless and preparation method thereof

Technical field

The present invention relates to silicon technology microelectromechanical systems (Micro-electromechanical Systems, MEMS), in particular to MEMS Electret Condencer Microphone of a kind of backplateless and preparation method thereof.

Background technology

The design of double-deck or plural layers has all been adopted in general silicon microphone design, comprises the backplane film that one deck sensitive membrane and one deck have a large amount of sound penetrating holes.The manufacture craft more complicated double-deck and plural layers design, and have problems such as " soft backplane ", adhesion, the someone has proposed the monofilm design for this reason, reference

One Chinese patent application number is 200480044734.4 to have disclosed a kind of silicon based microphone element and preparation method thereof.This microphone sensing element has the diaphragm of perforated plate adjoining on every limit and the angle.This diaphragm is placed in the one or more dorsal pores top that forms in the conductive substrates, and wherein dorsal pore is less than the width of diaphragm.Porous plate is suspended from the pore top above the substrate.Diaphragm is supported by mechanical spring, and mechanical spring has two ends, is connected to angle, limit or the center of porous plate and ends at the rigid liner that is fixed on the dielectric space layer.First electrode is formed on one or more rigid liner, and second electrode is formed at a place or many places on the substrate, thereby sets up variable capacitance circuit.

One Chinese patent application number is 200810166039.5 to have disclosed a kind of microphone sensing element of not having special-purpose back pole plate parts, and this sensor senses element comprises: have front and back and wherein be formed with the substrate of dorsal pore; Be formed at the dielectric spacer that has first thickness on the substrate face; Be arranged in said dorsal pore top and have the diaphragm of second thickness; With said diaphragm in abutting connection with a plurality of porous plates with second thickness, this porous plate and diaphragm are suspended from the air gap that has first thickness on the substrate; Be formed at a plurality of rigid liners that have second thickness on the dielectric spacer; Be connected to a plurality of mechanical springs of diaphragm, wherein each mechanical spring has second thickness and has two ends, and wherein an end is connected to diaphragm, and the other end is connected in the rigid liner; Be formed at first electrode on one or more rigid liners; With one or more second electrodes that are formed on the substrate; Wherein when diaphragm, porous plate and mechanical spring responded voice signal perpendicular to the substrate up-down vibration, first electrode and second electrode formed variable capacitance circuit.

One Chinese patent application number is 200610112887.9 to have disclosed a kind of single membrane capacitance type microphone, utilizes monofilm and substrate to form capacitance structure.Vibrating diaphragm is connected with overarm support upper surface through the overarm frame of overarm, forms overarm, vibrating diaphragm not at conplane three-dimensional vibrational structure; Overarm is soft, and vibrating diaphragm is hard, and during vibration, distortion mainly concentrates in the overarm, and vibrating diaphragm keeps translation basically; The vibrating diaphragm edge is provided with countless apertures and improves Frequency Response, makes etch pit simultaneously; In addition, make anti-concussion backstop on the chip.

To above-mentioned prior art, their whole principle is basic identical, all is through detecting vibrating membrane (sensitive membrane) capacitance variations of substrate to be obtained the detection to voice signal.In such design; In order to obtain higher sensitivity, need the air gap distance of vibrating membrane and substrate less, perhaps need vibrating membrane itself softer; To detect the changes in capacitance amount bigger for vibrating diaphragm when obtaining the voice signal of corresponding fixed amplitude, thereby make the sensitivity of microphone better.

But because when the microphone operate as normal; Exist high bias voltage between substrate and the vibrating membrane; Therefore when substrate and vibrating membrane gap smaller, the electrostatic force between substrate and vibrating membrane will increase, and makes the adhesive under electrostatic force of vibrating membrane and substrate; Cause the microphone non-output signal, thereby reduced the reliability of microphone.

Summary of the invention

The objective of the invention is to, MEMS Electret Condencer Microphone of a kind of backplateless and preparation method thereof is provided, in order to improve the reliability of microphone.

For realizing above-mentioned purpose; The technical scheme that the present invention adopts is that a kind of MEMS Electret Condencer Microphone of backplateless at first is provided, and it comprises: first pole plate and second pole plate, vibrating membrane and the lead-in wire of substrate, back of the body chamber, electric capacity; Wherein, back of the body chamber perforate is positioned at the substrate bottom; Vibrating membrane is arranged on the substrate, is used to detect acoustical vibration and converts displacement into; First pole plate is arranged on the substrate; Second pole plate is arranged on the vibrating membrane, and wherein second pole plate is provided with the projection that is used to prevent first pole plate and the second pole plate adhesive; Lead-in wire is used for first pole plate and second pole plate are drawn.

Preferable, said vibrating membrane is provided with one or more perforate.

Preferable, the perforate that is provided with on the said vibrating membrane is for circular or square.

Preferable, said second pole plate is one to have the slab construction of acoustical open-cell.

Preferable, said substrate is provided with back of the body chamber perforate.

Secondly the present invention also provides a kind of preparation method of MEMS Electret Condencer Microphone of backplateless; In order to realize above-mentioned device; It may further comprise the steps: growth first sacrifice layer on substrate; First structure sheaf of deposit above that, and first structure sheaf is graphical, obtain the vibrating membrane and first pole plate; On the vibrating membrane and first pole plate, obtain second sacrifice layer, and it is graphical; Form the backstop position on second sacrifice layer after graphically, and second structure sheaf of on second sacrifice layer, growing, second pole plate obtained; The borehole at the back side of substrate forms back of the body cavity configuration, and vibrating membrane is discharged; Carry out structure and discharge, erode the first unnecessary sacrifice layer and the material of second sacrifice layer.

The beneficial effect that reaches compared to prior art the present invention is; Acoustic diaphragm and capacitor plate branch through with microphone are arranged; Like this can be respectively the acoustic construction (being vibrating membrane) and the electricity structure (being capacitor plate) of microphone be carried out structure and process optimization, thereby improve the reliability of microphone.Simultaneously can realize less air gap, obtaining higher sensitivity of microphone or higher microphone signal to noise ratio, and simplify step of preparation process, reduce cost, overcome the problem that exists in the prior art.

Description of drawings

Fig. 1 is the MEMS Electret Condencer Microphone cutaway view of backplateless according to an embodiment of the invention;

Fig. 2 is the vertical view of the MEMS Electret Condencer Microphone of backplateless according to an embodiment of the invention;

Fig. 3 is the upward view according to the MEMS Electret Condencer Microphone of the backplateless of Fig. 2 embodiment;

Fig. 4 is preparation method's flow chart of the MEMS Electret Condencer Microphone of backplateless according to an embodiment of the invention.

Embodiment

To combine the accompanying drawing in the embodiment of the invention below, the technical scheme in the embodiment of the invention is carried out clear, intactly description, obviously, described embodiment only is the present invention's part embodiment, rather than whole embodiment.Based on the embodiment among the present invention, those of ordinary skills are not paying the every other embodiment that is obtained under the creative work prerequisite, all belong to the scope of the present invention's protection.

See also shown in Figure 1; It is the MEMS Electret Condencer Microphone cutaway view of backplateless according to an embodiment of the invention; Comprise:first pole plate 105 ofsubstrate 101, the back of thebody chamber 102, electric capacity andsecond pole plate 104, vibratingmembrane 103 and lead-in wire (not shown); Wherein, back of thebody chamber 102 is positioned at the below of vibratingmembrane 103; Vibratingmembrane 103 is arranged on thesubstrate 101, is used to detect acoustical vibration and converts displacement into;First pole plate 105 is arranged on thesubstrate 101;Second pole plate 104 is arranged on thevibrating membrane 103, and whereinsecond pole plate 104 is provided with the projection that is used to prevent

first pole plate

105 and 104 adhesives of second pole plate; Lead-in wire is used forfirst pole plate 105 andsecond pole plate 104 are drawn.

Present embodiment adopts the single-layer diaphragm structure, and through acoustic diaphragm and capacitor plate branch are arranged, realizes less air gap, thereby obtains higher sensitivity of microphone or higher microphone signal to noise ratio.This structure can improve the reliability of microphone simultaneously, has reduced cost, has overcome the problem that exists in the prior art.

For example, vibrating membrane is provided with one or more perforate in the embodiment in figure 1, with the operatic tunes air pressure of balance microphone vibrating membrane both sides.

For example, the perforate of above-mentioned vibrating membrane can be for circular or square.

For example, above-mentioned second pole plate is one to have the slab construction of acoustical open-cell, acoustical open-cell in order to sound transmission to vibrating membrane.

For example, above-mentioned substrate is provided with back of the body chamber perforate.

For example, above-mentioned second pole plate below is provided with outstanding backstop position, is pulled together in order to prevent first pole plate and second pole plate.

Clearer for those skilled in the art are understood its structure, please consult Fig. 2 and shown in Figure 3 respectively, it is respectively the top and bottom perspective views of the MEMS Electret Condencer Microphone of backplateless according to an embodiment of the invention.

Seeing also Fig. 4 is preparation method's flow chart of the MEMS Electret Condencer Microphone of backplateless according to an embodiment of the invention, and it may further comprise the steps:

Growth first sacrifice layer on the substrate of semi-conducting material, first structure sheaf of deposit above that, and first structure sheaf is graphical, obtain the vibrating membrane and first pole plate;

On the vibrating membrane and first pole plate, obtain second sacrifice layer, and it is graphical;

Form the backstop position on second sacrifice layer after graphically, and second structure sheaf of on second sacrifice layer, growing, second pole plate obtained;

The borehole at the back side of substrate forms back of the body cavity configuration, and vibrating membrane is discharged; Carry out structure and discharge, erode the first unnecessary sacrifice layer and the material of second sacrifice layer.

Present embodiment adopts the single-layer diaphragm structure, has simplified production technology, has improved the reliability of microphone, has reduced cost, has overcome the problem that exists in the prior art.

One of ordinary skill in the art will appreciate that: accompanying drawing is the sketch map of an embodiment, and module in the accompanying drawing or flow process might not be that embodiment of the present invention is necessary.

One of ordinary skill in the art will appreciate that: the module in the device among the embodiment can be described according to embodiment and be distributed in the device of embodiment, also can carry out respective change and be arranged in the one or more devices that are different from present embodiment.The module of the foregoing description can be merged into a module, also can further split into a plurality of submodules.

The invention described above embodiment sequence number is not represented the quality of embodiment just to description.

What should explain at last is: above embodiment is only in order to explaining technical scheme of the present invention, but not to its restriction; Although with reference to previous embodiment the present invention has been carried out detailed explanation, those of ordinary skill in the art is to be understood that: it still can be made amendment to the technical scheme that previous embodiment is put down in writing, and perhaps part technical characterictic wherein is equal to replacement; And these are revised or replacement, do not make the spirit and the scope of the essence disengaging embodiment of the invention technical scheme of relevant art scheme.

Claims

1. the MEMS Electret Condencer Microphone of a backplateless is characterized in that, comprising: first pole plate and second pole plate, vibrating membrane and the lead-in wire of substrate, back of the body chamber, electric capacity, wherein

Said back of the body chamber is positioned on the said substrate;

Said vibrating membrane is arranged on the said substrate, is used to detect acoustical vibration and converts displacement into;

Said first pole plate is arranged on the said substrate;

Said second pole plate is arranged on the said vibrating membrane, and wherein said second pole plate is provided with the projection that is used to prevent said first pole plate and the said second pole plate adhesive;

Said lead-in wire is used for said first pole plate and said second pole plate are drawn.

2. Electret Condencer Microphone according to claim 1 is characterized in that said vibrating membrane is provided with at least one perforate.

3. Electret Condencer Microphone according to claim 2 is characterized in that, the perforate that is provided with on the said vibrating membrane is for circular or square.

4. Electret Condencer Microphone according to claim 1 is characterized in that, said second pole plate is one to have the slab construction of acoustical open-cell.

5. Electret Condencer Microphone according to claim 1 is characterized in that, said substrate is provided with back of the body chamber perforate.

6. the preparation method of the MEMS Electret Condencer Microphone of a backplateless is characterized in that, may further comprise the steps:

Growth first sacrifice layer on a substrate, deposit first structure sheaf on described first sacrifice layer, and said first structure sheaf is graphical, obtain the vibrating membrane and first pole plate;

On said vibrating membrane and said first pole plate, obtain second sacrifice layer, and it is graphical;

Form the backstop position on said second sacrifice layer after graphically, and second structure sheaf of on said second sacrifice layer, growing, second pole plate obtained;

The borehole at the back side of said substrate forms back of the body cavity configuration, and said vibrating membrane is discharged;

Carry out structure and discharge, erode unnecessary said first sacrifice layer and the material of said second sacrifice layer.