CN102457801B - Difference MEMS capacitive microphone and preparation method thereof - Google Patents
Difference MEMS capacitive microphone and preparation method thereof Download PDFInfo
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- 238000002360 preparation method Methods 0.000 title claims abstract description 20
- 239000012528 membrane Substances 0.000 claims abstract description 107
- 239000000758 substrate Substances 0.000 claims abstract description 59
- 238000005137 deposition process Methods 0.000 claims description 24
- 238000005468 ion implantation Methods 0.000 claims description 4
- 239000004065 semiconductor Substances 0.000 claims description 2
- 230000035945 sensitivity Effects 0.000 description 13
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 description 12
- 229910052710 silicon Inorganic materials 0.000 description 12
- 239000010703 silicon Substances 0.000 description 12
- 239000003990 capacitor Substances 0.000 description 7
- 238000000034 method Methods 0.000 description 7
- 238000010586 diagram Methods 0.000 description 6
- 238000001514 detection method Methods 0.000 description 5
- 238000006073 displacement reaction Methods 0.000 description 5
- 239000011148 porous material Substances 0.000 description 5
- 239000000853 adhesive Substances 0.000 description 3
- 230000001070 adhesive effect Effects 0.000 description 3
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- 101000872083 Danio rerio Delta-like protein C Proteins 0.000 description 2
- 230000005611 electricity Effects 0.000 description 2
- 238000005516 engineering process Methods 0.000 description 2
- 125000006850 spacer group Chemical group 0.000 description 2
- 239000000725 suspension Substances 0.000 description 2
- 239000012141 concentrate Substances 0.000 description 1
- 239000004020 conductor Substances 0.000 description 1
- 238000010276 construction Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000005530 etching Methods 0.000 description 1
- 239000011521 glass Substances 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- 229910021421 monocrystalline silicon Inorganic materials 0.000 description 1
- 229910021420 polycrystalline silicon Inorganic materials 0.000 description 1
- 229920005591 polysilicon Polymers 0.000 description 1
- 230000005236 sound signal Effects 0.000 description 1
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Abstract
The invention discloses a kind of difference MEMS capacitive microphone and preparation method thereof, wherein Electret Condencer Microphone comprises: substrate, back of the body chamber, top crown, bottom crown, middle plate and vibrating membrane, wherein, the edge of vibrating membrane is fixedly connected on substrate, vibrating membrane is provided with at least one perforate, the below of vibrating membrane is back of the body chamber; Middle plate is between top crown and bottom crown, and top crown and middle plate form the first electric capacity, and bottom crown and middle plate form the second electric capacity; Middle plate is fixedly connected on vibrating membrane, for changing the position of middle plate to change the capacitance of the first electric capacity and the second electric capacity when vibration occurs with sound vibrating membrane; First electric capacity and the second electric capacity form differential capacitance pair, for being electrically connected the acquisition and processing of horizontal electrical signal of going forward side by side in a differential manner.
Description
Technical field
The present invention relates to the microelectromechanical systems (Micro-electromechanicalSystems, MEMS) of silicon technology, in particular to a kind of difference MEMS capacitive microphone and preparation method thereof.
Background technology
General silicon microphone design all have employed single-ended connected mode, referenced patent application:
Patent application CN200480044734.4 discloses 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 angle.This diaphragm is placed in above one or more dorsal pores of being formed in conductive substrates, and wherein dorsal pore is less than the width of diaphragm.Porous plate is suspended from above the pore above substrate.Diaphragm is supported by mechanical spring, and mechanical spring has two ends, is connected to the angle of porous plate, limit or center and ends at the rigid liner be fixed on dielectric space layer.First electrode is formed on one or more rigid liner, and the second electrode is formed at a place on substrate or many places, thus sets up variable capacitance circuit.
Patent application CN200810166039.5 discloses a kind of microphone sensing element without Special back pole plate parts, and this sensor senses element comprises: have front and back and be wherein formed with the substrate of dorsal pore; Be formed at dielectric spacer substrate face with the first thickness; Be arranged in the diaphragm above described dorsal pore with the second thickness; Adjoin multiple porous plates with the second thickness with described diaphragm, this porous plate and diaphragm be suspended from substrate has the first thickness air gap on; Be formed at multiple rigid liners dielectric spacer with the second thickness; Be connected to multiple mechanical springs of diaphragm, wherein each mechanical spring has the second thickness and has two ends, and wherein one end is connected to diaphragm, and the other end is connected to one in rigid liner; Be formed at the first electrode on one or more rigid liner, with one or more second electrodes be formed on substrate, wherein when diaphragm, porous plate and mechanical spring response voice signal is perpendicular to substrate up-down vibration, the first electrode and the second electrode form variable capacitance circuit.
Patent application CN200610112887.9 discloses a kind of single membrane capacitance type microphone, utilizes monofilm and substrate to form capacitance structure.Vibrating diaphragm supports upper surface by the overarm frame of overarm with overarm and is connected, and 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 overarm, and vibrating diaphragm keeps translation substantially; Vibrating diaphragm edge is provided with numerous small holes and improves Frequency Response, makes etch pit simultaneously; In addition, chip makes anti-oscillating backstop.
The capacitance type microphone chip that patent application CN200810057874.5 discloses utilizes vibrating diaphragm to be connected with substrate and backplane upper surface, form cantilever design or accurate free diaphragm structure, vibrating diaphragm keeps freely in the horizontal direction, the residual stress of sufficient release vibrating diaphragm, improves the up-down vibration performance of vibrating diaphragm; Backstop and lower backstop on vibrating diaphragm free end edge has, keep the stable state of vibrating diaphragm; Vibrating diaphragm free end edge can make suspension beam structure, and lower backstop is located under suspension beam structure, keeps the vibration characteristics of vibrating diaphragm softness.
The general principle of capacitive-type silicon microphone is all the detection realizing voice signal to the electric capacitance change of another capacitance electrode by detecting vibrating membrane (sensitive membrane).In such design, in order to obtain higher sensitivity, need the air gap distance of vibrating membrane and another capacitance electrode less, or need vibrating membrane itself softer, during to obtain the voice signal of corresponding fixed amplitude, the variable quantity of vibrating diaphragm Detection capacitance is larger, thus makes the output sensitivity of microphone higher.
But due to when microphone normally works, higher bias voltage is there is between substrate and vibrating membrane, therefore when substrate and vibrating membrane gap smaller, electrostatic force between substrate and vibrating membrane will increase, make vibrating membrane and substrate adhesive under electrostatic force, cause microphone non-output signal, reduce the reliability of microphone.Therefore in the design of such silicon microphone, adopt and reduce air gap distance, or the softer vibrating membrane of setting is restricted with the method improving sensitivity of microphone.
In addition, when bias voltage is constant, when the sensitivity of microphone increases, for the input audio signal of equal magnitude, the motion amplitude of microphone diaphragm can increase.This can cause the harmonic distortion of microphone to increase.
Meanwhile, generally silicon microphone needs a HVB high voltage bias voltage.And the noise voltage that this HVB high voltage bias voltage brings can increase the noise of bulk silicon microphone, in typical design, the noise of bias voltage contribution accounts for more than 25% of bulk silicon microphone noise.Therefore the existence of the noise of bias voltage, limits the noise level of bulk silicon microphone.
Summary of the invention
The invention provides a kind of difference MEMS capacitive microphone and preparation method thereof, in order to reduce the noise of microphone, reduce the distortion of MEMS microphone, increase the sensitivity of microphone.
One aspect of the present invention, provide a kind of difference MEMS capacitive microphone, it comprises: substrate, back of the body chamber, top crown, bottom crown, middle plate and vibrating membrane, wherein, the edge of vibrating membrane is fixedly connected on substrate, vibrating membrane is provided with at least one perforate, the below of vibrating membrane is back of the body chamber; Middle plate is between top crown and bottom crown, and top crown and middle plate form the first electric capacity, and bottom crown and middle plate form the second electric capacity; Middle plate is fixedly connected on vibrating membrane, for changing the position of middle plate to change the capacitance of the first electric capacity and the second electric capacity when vibration occurs vibrating membrane; First electric capacity and the second electric capacity form differential capacitance pair, for being electrically connected the acquisition and processing of horizontal electrical signal of going forward side by side in a differential manner.
Another aspect of the present invention, provide a kind of preparation method of difference MEMS capacitive microphone, it comprises the following steps: on substrate, form vibrating membrane, and vibrating membrane has at least one perforate; Adopt deposition process to obtain the first sacrifice layer, the first sacrifice layer covers vibrating membrane; First sacrifice layer is formed bottom crown and the first middle plate, and wherein the first middle plate is fixedly connected on vibrating membrane; Adopt deposition process to obtain the second sacrifice layer, the second sacrifice layer covers bottom crown and the first middle plate; Second sacrifice layer is formed top crown and the second middle plate, and wherein the second middle plate is fixedly connected on vibrating membrane; First sacrifice layer and the second sacrifice layer are etched away, and at the back side borehole of substrate, from the back side of substrate, vibrating membrane is discharged.
Another aspect of the present invention, additionally provide a kind of preparation method of difference MEMS capacitive microphone, it comprises the following steps: on substrate, form vibrating membrane, and vibrating membrane has at least one perforate; Adopt deposition process to obtain the first sacrifice layer, the first sacrifice layer covers vibrating membrane, and the first sacrifice layer forms bottom crown; Adopt deposition process to obtain the second sacrifice layer, the second sacrifice layer covers bottom crown; Second sacrifice layer forms middle plate, and wherein middle plate is fixedly connected on vibrating membrane respectively; Adopt deposition process to obtain the 3rd sacrifice layer, the 3rd sacrifice layer covers middle plate and vibrating membrane, and forms top crown on the 3rd sacrifice layer; First sacrifice layer, the second sacrifice layer and the 3rd sacrifice layer are etched away, and at the back side borehole of substrate, from the back side of substrate, vibrating membrane is discharged.
First electric capacity and the second electric capacity are formed differential capacitance pair by above-described embodiment, because the electrostatic suction power between the first electric capacity and the second capacitor plate is cancelled out each other, very little air gap can be realized, thus obtain higher sensitivity of microphone or higher microphone signal to noise ratio, improve the reliability of microphone, and reduce cost, overcome problems of the prior art.
Accompanying drawing explanation
In order to be illustrated more clearly in the embodiment of the present invention or technical scheme of the prior art, be briefly described to the accompanying drawing used required in embodiment or description of the prior art below, apparently, accompanying drawing in the following describes is only some embodiments of the present invention, for those of ordinary skill in the art, under the prerequisite not paying creative work, other accompanying drawing can also be obtained according to these accompanying drawings.
Fig. 1 is difference MEMS capacitive microphone schematic diagram according to an embodiment of the invention;
Fig. 2 is according to the profile along A-A ' in Fig. 1 embodiment; Fig. 3 is according to the profile along B-B ' in Fig. 1 embodiment;
Fig. 4 is difference MEMS capacitive microphone profile in accordance with another embodiment of the present invention;
Fig. 5 is difference MEMS capacitive microphone schematic diagram in accordance with a preferred embodiment of the present invention;
Fig. 6 is according to the profile of Fig. 5 along A-A ';
Fig. 7 is according to the profile of Fig. 5 along B-B ';
Fig. 8 is the profile forming vibrating membrane according to the employing growth technique of Fig. 5 embodiment on substrate;
Fig. 9 is preparation method's flow chart of difference MEMS capacitive microphone according to a first embodiment of the present invention;
Figure 10 is preparation method's flow chart of difference MEMS capacitive microphone according to a second embodiment of the present invention;
Figure 11 is preparation method's flow chart of difference MEMS capacitive microphone according to a third embodiment of the present invention;
Figure 12 is preparation method's flow chart of difference MEMS capacitive microphone according to a fourth embodiment of the present invention.
Embodiment
Below in conjunction with the accompanying drawing in the embodiment of the present invention, be clearly and completely described the technical scheme in the embodiment of the present invention, obviously, described embodiment is only the present invention's part embodiment, instead of whole embodiments.Based on the embodiment in the present invention, those of ordinary skill in the art, not paying the every other embodiment obtained under creative work prerequisite, belong to the scope of protection of the invention.
Fig. 1 is difference MEMS capacitive microphone schematic diagram according to an embodiment of the invention, it comprises: substrate 301, back of the body chamber 305, top crown, bottom crown 302, middle plate 303, vibrating membrane 304, be located at least one perforate 306 on vibrating membrane 304 and differential capacitance detection unit (not shown), wherein, the edge of vibrating membrane 304 is fixedly connected on substrate 301, and the below of vibrating membrane is back of the body chamber 305; Middle plate 303 is between top crown and bottom crown 302, and top crown and middle plate 303 form the first electric capacity, and bottom crown 302 and middle plate 303 form the second electric capacity; Middle plate 303 is fixedly connected on vibrating membrane 304, for changing the position of middle plate 303 to change the capacitance of the first electric capacity and the second electric capacity when vibration occurs vibrating membrane 304; First electric capacity and the second electric capacity form differential capacitance pair, for being electrically connected the acquisition and processing of horizontal electrical signal of going forward side by side in a differential manner.
When the pressure difference caused when there being voice signal is applied on vibrating membrane, vibrating membrane can produce displacement, drives above-mentioned middle plate to produce displacement, thus changes the capacitance of the first electric capacity and the second electric capacity and be converted into electricity output.
First electric capacity and the second electric capacity are formed differential capacitance pair by the present embodiment, because the electrostatic suction power between the first electric capacity and the second capacitor plate is cancelled out each other, therefore very little air gap can be realized, thus obtain higher sensitivity of microphone or higher microphone signal to noise ratio, improve the reliability of microphone, and reduce cost; Simultaneously by vibrating membrane and capacitor plate are separated, can be optimized acoustic characteristic and electrology characteristic respectively, finally realize difference microphone detection architecture easily; Achieve less air gap, thus obtain higher sensitivity of microphone or higher microphone signal to noise ratio, can be applied to easily in the microphone of advance acoustic form.
Due to the capacitance change deltaC of Electret Condencer Microphone and vibrating diaphragm displacement deltaD relation as follows:
DeltaC is proportional to deltaD/d* (d-deltaD), and d is the spacing between electric capacity two pole plates here.
This variation relation is a nonlinear function, there are 2 subharmonic amounts and 3 subharmonic amounts simultaneously.In the application of microphone requires, when typical linearity index is maximum sound pressure level input, overall harmonic distortion is less than 1%, therefore when the vibrating membrane displacement variable increase when unit sound pressure level inputs, namely, when microphone output capacitance variable quantity signal increases, the speed of 2 powers that harmonic wave increases with signal amplitude increases.In order to obtain suitable linearity, need artificial increase microphone pole plate air gap, therefore when identical output capacitance variable quantity signal, the area of microphone needs to increase.
By using differential configuration microphone, can increase its linearity largely, capacitance change and the vibrating diaphragm displacement relation of difference microphone are as follows:
DeltaC is proportional to deltaD/ (d^2-deltaD^2),
Meeting under same harmonic distortion requirement condition, its maximum capacitor variable quantity is more than 10 times of non-differential microphone.Therefore, when identical output capacitance variable quantity signal, the area of microphone can be less, and cost can be lower.
When single-ended silicon microphone normally works, there is HVB high voltage bias voltage between fixed polar plate and movable plate, therefore when pole plate gap smaller time, the electrostatic force between pole plate will increase, fixed polar plate and movable plate cause adhesive due to electrostatic force, thus produce the integrity problem of microphone.Same, when the bias voltage of microphone sets too high, or when movable plate or vibrating membrane are crossed soft, also can cause the electrostatic suction between fixed polar plate and movable plate.Therefore in typical silicon microphone design, for preventing electrostatic suction, needing the pole plate gap to electric capacity when designing, the parameter such as rigidity of bias voltage and vibrating membrane leaves larger design capacity.The restriction of these design parameters above-mentioned makes to be difficult to obtain optimum sensitivity in the design of silicon microphone, and in order to obtain the acceptable range of sensitivity, then can sacrifice the index of the aspects such as the reliability of microphone, cost.
By adopting the microphone structure of differential mode, electrostatic force between the capacitor plate of 2 electric capacity is cancelled out each other, eliminate electrostatic force and cause pole plate adhesive and the design restriction that brings, thus lower cost can be obtained under identical sensitivity design indicator conditions, or higher reliability.
In addition, by adopting the capacitance structure of differential mode and follow-up differential amplifier circuit.The voltage noise that HVB high voltage bias voltage exists shows as common-mode noise in follow-up differential amplifier circuit, and is eliminated by difference channel.Thus lower Noise Background can be obtained, realize excellent microphone noise performance.
Fig. 2 is according to the profile along A-A ' in Fig. 1 embodiment; Fig. 3 is according to the profile along B-B ' in Fig. 1 embodiment.As shown in Figures 2 and 3, top crown and bottom crown asymmetric relative to middle plate, the projected area of top crown in middle plate 303 and the distance between top crown with middle plate 303 are equal with the projected area of bottom crown 302 in middle plate 303 and the distance between bottom crown 302 with middle plate 303 respectively, drive when vibrating membrane 304 vibrates the position of middle plate 303 to change, thus change the capacitance of the first electric capacity and the second electric capacity.
Fig. 4 is difference MEMS capacitive microphone profile in accordance with another embodiment of the present invention.Vibrating membrane 304 adopts growth technique to be formed on substrate in the diagram, and in Fig. 3, vibrating membrane 304 adopts etching technics (such as selective etch) to be formed on substrate.
Such as, the first pole plate, middle plate and the second pole plate are respectively comb structure, by using comb structure, can overcome slab construction and preparing the huge difficulty in process that three layers of vibrating membrane bring.
The material of substrate can be semi-conducting material, such as monocrystalline silicon, but also can be glass, pottery or metal etc.
Fig. 5 is difference MEMS capacitive microphone schematic diagram in accordance with a preferred embodiment of the present invention, it comprises: substrate 401, back of the body chamber 405, top crown, bottom crown 402, middle plate 403, vibrating membrane 404 and at least one perforate 406 be located on vibrating membrane 404, wherein, the edge of vibrating membrane 404 is fixedly connected with on the substrate 401, and the below of vibrating membrane 404 is back of the body chamber 405; Middle plate 403 between top crown and bottom crown 402, top crown and bottom crown 402 symmetrical relative to middle plate 403, top crown and middle plate 403 form the first electric capacity, and bottom crown 402 and middle plate 403 form the second electric capacity; Middle plate 403 is fixedly connected on vibrating membrane 404, for changing the position of middle plate 403 to change the capacitance of the first electric capacity and the second electric capacity when vibration occurs vibrating membrane 404; First electric capacity and the second electric capacity form differential capacitance pair, for being electrically connected the acquisition and processing of horizontal electrical signal of going forward side by side in a differential manner.
Fig. 6 is according to the profile of Fig. 5 along A-A ', and Fig. 7 is according to the profile of Fig. 5 along B-B '.As shown in Figure 6, corresponding a pair top crown of each middle plate 403 and bottom crown, form two electric capacity.Fig. 8 is the profile forming vibrating membrane according to the employing growth technique of Fig. 5 embodiment on substrate.
In above-described embodiment, can conduct electricity also can be non-conductive for the material of vibrating membrane, do not affect the effect of this embodiment, such as, polysilicon can be adopted to be made.
Such as, in the above-described embodiments, difference MEMS capacitive microphone is provided with the conduction being electrically connected to external circuit and connects and leading-out wire structure, for the differential capacitance that the first electric capacity and the second electric capacity are formed, the signal of telecommunication detected is sent in external circuit.
Such as, in the above-described embodiments, the material of top crown, middle plate and bottom crown is electric conducting material.
Fig. 9 is preparation method's flow chart of difference MEMS capacitive microphone according to a first embodiment of the present invention, and it comprises the following steps: the selection area on substrate adopts ion implantation to form vibrating membrane, and vibrating membrane has at least one perforate; Adopt deposition process to obtain the first sacrifice layer, the first sacrifice layer covers vibrating membrane; First sacrifice layer is formed bottom crown and the first middle plate, and wherein middle plate is fixedly connected on vibrating membrane; Adopt deposition process to obtain the second sacrifice layer, the second sacrifice layer covers bottom crown and the first middle plate; Second sacrifice layer is formed top crown and the second middle plate, and wherein the second middle plate is fixedly connected on vibrating membrane; First sacrifice layer and the second sacrifice layer are etched away, and at the back side borehole of substrate, from the back side of substrate, vibrating membrane is discharged.
Figure 10 is preparation method's flow chart of difference MEMS capacitive microphone according to a second embodiment of the present invention, and it comprises the following steps: on substrate, adopt deposition process to obtain sacrifice layer, sacrifice layer forms vibrating membrane, and vibrating membrane has at least one perforate; Adopt deposition process to obtain the first sacrifice layer, the first sacrifice layer covers vibrating membrane; First sacrifice layer is formed bottom crown and the first middle plate, and wherein middle plate is fixedly connected on vibrating membrane; Adopt deposition process to obtain the second sacrifice layer, the second sacrifice layer covers bottom crown and the first middle plate; Second sacrifice layer is formed top crown and the second middle plate, and wherein the second middle plate is fixedly connected on vibrating membrane; Sacrifice layer, the first sacrifice layer and the second sacrifice layer are etched away, and at the back side borehole of substrate, from the back side of substrate, vibrating membrane is discharged.
Figure 11 is preparation method's flow chart of difference MEMS capacitive microphone according to a third embodiment of the present invention, and it comprises the following steps: selection area on substrate, and adopt ion implantation to form vibrating membrane on selection area, vibrating membrane has at least one perforate; Adopt deposition process to obtain the first sacrifice layer, the first sacrifice layer covers vibrating membrane, and the first sacrifice layer forms bottom crown; Adopt deposition process to obtain the second sacrifice layer, the second sacrifice layer covers bottom crown; Second sacrifice layer forms middle plate, and wherein middle plate is fixedly connected on vibrating membrane; Adopt deposition process to obtain the 3rd sacrifice layer, the 3rd sacrifice layer covers middle plate and vibrating membrane, and forms top crown on the 3rd sacrifice layer; First sacrifice layer, the second sacrifice layer and the 3rd sacrifice layer are etched away, and at the back side borehole of substrate, from the back side of substrate, vibrating membrane is discharged.
Figure 12 is preparation method's flow chart of difference MEMS capacitive microphone according to a fourth embodiment of the present invention, and it comprises the following steps: on substrate, adopt deposition process to obtain sacrifice layer, sacrifice layer forms vibrating membrane, and vibrating membrane has at least one perforate; Adopt deposition process to obtain the first sacrifice layer, the first sacrifice layer covers vibrating membrane, and the first sacrifice layer forms bottom crown; Adopt deposition process to obtain the second sacrifice layer, the second sacrifice layer covers bottom crown; Second sacrifice layer forms middle plate, and wherein middle plate is fixedly connected on vibrating membrane; Adopt deposition process to obtain the 3rd sacrifice layer, the 3rd sacrifice layer covers middle plate, and forms top crown on the 3rd sacrifice layer; Sacrifice layer, the first sacrifice layer, the second sacrifice layer and the 3rd sacrifice layer are etched away, and at the back side borehole of substrate, from the back side of substrate, vibrating membrane is discharged.
The MEMS capacitive microphone that above-described embodiment obtains, further the first electric capacity and the second electric capacity are formed differential capacitance pair, electrostatic suction power between first electric capacity and the second capacitor plate is cancelled out each other, very little air gap can be realized, thus obtain higher sensitivity of microphone or higher microphone signal to noise ratio, improve the reliability of microphone, and reduce cost; Vibrating membrane and capacitor plate are separated simultaneously, therefore can be optimized acoustic characteristic and electrology characteristic respectively, difference microphone detection architecture can be realized easily; Achieve less air gap, thus obtain higher sensitivity of microphone or higher microphone signal to noise ratio, and the restriction that the electrostatic force do not produced by bias voltage affects, can be applied to easily in the microphone of advance acoustic form.
One of ordinary skill in the art will appreciate that: accompanying drawing is the schematic diagram of an embodiment, the module in accompanying drawing or flow process might not be that enforcement the present invention is necessary.
One of ordinary skill in the art will appreciate that: the module in the device in embodiment can describe 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 being different from the present embodiment.The module of above-described embodiment can merge into a module, also can split into multiple submodule further.
The invention described above embodiment sequence number, just to describing, does not represent the quality of embodiment.
Last it is noted that above embodiment is only in order to illustrate technical scheme of the present invention, be not intended to limit; Although with reference to previous embodiment to invention has been detailed description, those of ordinary skill in the art is to be understood that: it still can be modified to the technical scheme described in previous embodiment, or carries out equivalent replacement to wherein portion of techniques feature; And these amendments or replacement, do not make the essence of appropriate technical solution depart from the spirit and scope of embodiment of the present invention technical scheme.
Claims (8)
1. a difference MEMS capacitive microphone, is characterized in that, comprising: substrate, back of the body chamber, top crown, bottom crown, middle plate and vibrating membrane, wherein
The edge of described vibrating membrane is fixedly connected with over the substrate, described vibrating membrane is provided with at least one perforate, and the below of described vibrating membrane is described back of the body chamber;
Described top crown and described middle plate form the first electric capacity, and described bottom crown and described middle plate form the second electric capacity;
Described middle plate is fixedly connected on described vibrating membrane, for changing the position of described middle plate to change the capacitance of described first electric capacity and described second electric capacity when described vibrating membrane, with sound, vibration occurs;
Described first electric capacity and described second electric capacity form differential capacitance pair, for being electrically connected the acquisition and processing of horizontal electrical signal of going forward side by side in a differential manner.
2. Electret Condencer Microphone according to claim 1, is characterized in that, described top crown and described bottom crown are relative to described middle plate symmetry.
3. Electret Condencer Microphone according to claim 1, is characterized in that, described top crown and described bottom crown asymmetric relative to described middle plate.
4. Electret Condencer Microphone according to claim 1, is characterized in that, described top crown, described middle plate and described bottom crown are respectively comb structure.
5. a preparation method for difference MEMS capacitive microphone, is characterized in that, comprises the following steps:
Substrate forms vibrating membrane, and described vibrating membrane has at least one perforate;
Adopt deposition process to obtain the first sacrifice layer, described first sacrifice layer covers described vibrating membrane;
Described first sacrifice layer is formed bottom crown and the first middle plate, and wherein said first middle plate is fixedly connected on described vibrating membrane;
Adopt deposition process to obtain the second sacrifice layer, described second sacrifice layer covers described bottom crown and described first middle plate;
Described second sacrifice layer is formed top crown and the second middle plate, and wherein said second middle plate is fixedly connected on described vibrating membrane;
Described first sacrifice layer and described second sacrifice layer are etched away, and at the back side borehole of described substrate, from the back side of described substrate, described vibrating membrane is discharged.
6. preparation method according to claim 5, is characterized in that, the substrate of semi-conducting material is formed vibrating membrane step be:
Adopt deposition process to obtain sacrifice layer over the substrate, described sacrifice layer forms vibrating membrane; Or
Selection area over the substrate, adopts ion implantation to form vibrating membrane on described selection area.
7. a preparation method for difference MEMS capacitive microphone, is characterized in that, comprises the following steps:
Substrate forms vibrating membrane, and described vibrating membrane has at least one perforate;
Adopt deposition process to obtain the first sacrifice layer, described first sacrifice layer covers described vibrating membrane, and described first sacrifice layer forms bottom crown;
Adopt deposition process to obtain the second sacrifice layer, described second sacrifice layer covers described bottom crown;
Described second sacrifice layer forms middle plate, and wherein said middle plate is fixedly connected on described vibrating membrane respectively;
Adopt deposition process to obtain the 3rd sacrifice layer, described 3rd sacrifice layer covers described middle plate and described vibrating membrane, and forms top crown on described 3rd sacrifice layer;
Described first sacrifice layer, described second sacrifice layer and the 3rd sacrifice layer are etched away, and at the back side borehole of described substrate, from the back side of described substrate, described vibrating membrane is discharged.
8. preparation method according to claim 7, is characterized in that, substrate is formed vibrating membrane step be:
Adopt deposition process to obtain sacrifice layer over the substrate, described sacrifice layer forms vibrating membrane; Or
Selection area over the substrate, adopts ion implantation to form vibrating membrane on described selection area.
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| CN112822615B (en) * | 2020-12-31 | 2022-08-05 | 苏州敏芯微电子技术股份有限公司 | Bone conduction MEMS chip, preparation method thereof and bone conduction pickup device |
| CN113423050B (en) * | 2021-06-18 | 2024-03-08 | 杭州士兰微电子股份有限公司 | MEMS system |
| US20240391756A1 (en) * | 2023-05-24 | 2024-11-28 | AAC Technologies Pte. Ltd. | Mems sensor and method for forming the same |
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| CN201163820Y (en) * | 2008-02-20 | 2008-12-10 | 歌尔声学股份有限公司 | Condenser Microphone Chip |
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| JP5165294B2 (en) * | 2007-07-06 | 2013-03-21 | 三菱電機株式会社 | Capacitance type acceleration sensor |
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| CN2424450Y (en) * | 2000-06-02 | 2001-03-21 | 中国科学院上海冶金研究所 | Micromechanical comb capacity type acceleration transducer |
| CN201163820Y (en) * | 2008-02-20 | 2008-12-10 | 歌尔声学股份有限公司 | Condenser Microphone Chip |
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