CN100455142C - Capacitance type sound sensor in micro mechanical and electrical structure - Google Patents
Capacitance type sound sensor in micro mechanical and electrical structure Download PDFInfo
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- CN100455142C CN100455142C CNB2005100351140A CN200510035114A CN100455142C CN 100455142 C CN100455142 C CN 100455142C CN B2005100351140 A CNB2005100351140 A CN B2005100351140A CN 200510035114 A CN200510035114 A CN 200510035114A CN 100455142 C CN100455142 C CN 100455142C
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- vibrating diaphragm
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Abstract
The present invention relates to a capacitor type microcomputer electrical structure sound sensor which comprises a base board, a back pole board which is fixed to the base board through a supporting end and has a plurality of sound holes and a vibrating diaphragm hung on the base board. The edge of the hung vibrating diaphragm is fixed to one position or many positions of the base board, an air gap is formed between the back pole board and the vibrating diaphragm, and an electrode is covered on the vibrating diaphragm. A capacitor is formed between the vibrating diaphragm and a back pole board electrode, the vibrating diaphragm is a shallow ripple vibrating diaphragm, and the back pole board electrode is arranged at the right side or the reverse side of the back pole board. The capacitor type microcomputer electrical structure sound sensor of the present invention has the characteristics of wide bandwidth, high sensitivity, etc. The performance is stable and reliable, and the fluctuation noise with less than 300Hz low frequency band can be effectively restrained.
Description
Technical field
The present invention relates to a kind of sound transducer (being commonly called as microphone), relate in particular to a kind of capacitance type sound sensor in micro mechanical and electrical structure.
Background technology
The appearance of micro electromechanical structure (MEMS, Mciro-electro-mechanical Systems) processing technology makes that producing the capacitive MEMS sound transducer in batches becomes possibility.By adopting the MEMS processing technology, can optimize the performance parameter of sound transducer, simultaneously also for simplifying manufacture process and designing integrated product and provide convenience.Adopting the MEMS technological design to make sound transducer was described in numerous publications and patent documentation.For example, the 5th, 619,476,5,870,351,5,894,452 and 6,493, No. 288 United States Patent (USP)s have been described the making of condenser type sonac.And the 5th, 146,435,5,452,268 and 6,870, No. 937 United States Patent (USP)s have also been described several condenser type sound transducers that are mainly used in tonal range.In these product structures, most movably vibrating membrane supports by substrate or as the insulating barrier of silicon nitride, silica and polyamide.The edge join of supporter and line film makes vibrating diaphragm to vibrate with the sound wave that is delivered to above it by on-load voltage between the conducting film on substrate and vibrating diaphragm surface together.A special example is arranged, and is the 6th, 535, and in No. 460 United States Patent (USP)s, its described embodiment freely is arranged on vibrating membrane on the support ring.
Many MEMS sound transducers have used and common test microphone and the similar diaphragm structure of recording microphone, as shown in Figure 1.In this traditional structure, include the vibrating diaphragm 1 that is suspended on the back pole plate 5, back pole plate 5 is provided with some hole 3.When the sound wave of incident drives vibrating diaphragm 1 and when changing the electric capacity of Electret Condencer Microphone 2, promptly may detect the size of voice signal.Under normal conditions, the capacitance variations of Electret Condencer Microphone 2 is that the output current under permanent bias voltage detects between the upper/lower electrode 8 by measuring.Acoustic pressure hole 4 such as be provided with in the back operatic tunes 7, press to back pole plate 5 to vibrating diaphragm 1 when preventing air pressure fluctuation.For the accurate Electret Condencer Microphone of measuring or calibrate usefulness, because during the about 20 μ m of the air gap 6 between vibrating diaphragm 1 and back pole plate 5, product has the uniform frequency response curve, but for the MEMS microphone, the diameter of vibrating diaphragm 1 has only the 1-2mm size usually, air gap 6 has only several microns, but will keep the sensitivity suitable with common microphone.And undersized air gap like this has strengthened the squeeze Film Damping Effect of product, and has introduced distortion and loss with frequency change.These phenomenons all are that we do not wish that the mechanical response that occurs with audio frequency that obtains changes.Because it is contradictory that wide Hz-KHz and high sensitivity will obtain simultaneously, because big acoustic pressure can make the vibrating diaphragm damage of breaking under its normal bias voltage, so the microphone of this employing traditional structure must have only lower sensitivity, the sensitivity in low frequency ranges is especially true.
In order to obtain wide bandwidth and high sensitivity, exploitation high-performance vibrating diaphragm is the key of making the condenser type sound transducer.Yet to the extremely thin vibrating diaphragm of majority, if can't accurately control processing procedure, bigger residual stress has adverse effect to properties of product, and is low and unstable as sensitivity.A kind of technology that obtains the low stress vibrating diaphragm is to adopt sandwich structure, and this structure is that the different layers that will have tensile stress and compression respectively combines and constitutes.What disclose in previously described the 6th, 535, No. 460 United States Patent (USP)s is again a kind of structure, and it is unsettled to discharge mechanical stress to be about to vibrating diaphragm.But in this case, free unsettled vibrating diaphragm sensitivity is unstable and can produce unwanted being displaced sideways, thereby produces problems such as spurious signal and poor reliability.
Summary of the invention
Technical problem to be solved by this invention is to provide a kind of capacitance type sound sensor in micro mechanical and electrical structure, and it has characteristics such as wide bandwidth and high sensitivity, and is not only stable and reliable for performance, and can effectively suppress the fluctuation noise of the following low-frequency band of 300HZ.
For solving the problems of the technologies described above, the technical solution adopted in the present invention is: a kind of capacitance type sound sensor in micro mechanical and electrical structure is provided, comprises: a substrate; Be fixed on the back pole plate that has several hole on the described substrate by support end; Be suspended on the vibrating diaphragm on the described substrate; The vibrating diaphragm edge that hangs is fixed on one or more positions of described substrate, forms air gap between described back pole plate and the vibrating diaphragm, is covered with electrode on the vibrating diaphragm, forms electric capacity between vibrating diaphragm and the back pole plate electrode; Described vibrating diaphragm is the shallow corrugated vibrating diaphragm, and described back pole plate electrode is arranged at the front or the reverse side of back pole plate.
Further improvement in the technical proposal is: described back pole plate is provided with the stop bit device that can prevent that described vibrating diaphragm from collapsing to the back pole plate transition shift.
Further improvement in the technical proposal is: described stop bit device is the circulus that is distributed in the discontinuous stop bit post of a circumference or is all continuous distribution.
Further improvement in the technical proposal is: the line film circumference on the described shallow corrugated vibrating diaphragm is provided with a series of through holes, the size of through hole is made the diameter unanimity or inconsistent according to the needs of filtering or is distributed by rule, forming the acoustic filter that filters certain frequency or certain frequency scope sound.
Further improvement in the technical proposal is: the circumference in sound hole is provided with a series of through holes on the described back pole plate, when external atmosphere pressure slowly changed, the atmospheric pressure that is delivered on the described vibrating diaphragm can discharge by the sound hole on cavity between described through hole and vibrating diaphragm and the back pole plate and the back pole plate.
The invention has the beneficial effects as follows: because the vibrating diaphragm that capacitance type sound sensor in micro mechanical and electrical structure of the present invention adopts is the shallow corrugated vibrating diaphragm, therefore it can discharge the stress in the vibrating diaphragm, and because the vibrating diaphragm edge that the present invention hangs is fixed on one or more positions of substrate, therefore the present invention has wide bandwidth, stable and reliable for performance, can effectively suppress the advantage of the fluctuation noise of the following low-frequency band of 300HZ.
Description of drawings
Fig. 1 is the profile of traditional capacitance type sound sensor in micro mechanical and electrical structure.
Fig. 2 is the vertical view of the capacitance type sound sensor in micro mechanical and electrical structure of the present invention's first embodiment.
Fig. 3 is along the profile of the A-A ' direction of Fig. 2 when the back pole plate electrode is positioned at the back pole plate reverse side.
Fig. 4 is positioned at back pole plate profile along the A-A ' direction of Fig. 2 when positive when the back pole plate electrode.
Fig. 5 is the vertical view of the capacitance type sound sensor in micro mechanical and electrical structure of the present invention's second embodiment.
Fig. 6 is the vertical view of shallow corrugated vibrating diaphragm shown in Figure 5.
Fig. 7 is the profile along the B-B ' direction of Fig. 5.
Embodiment
We can obtain the capacitance type sound sensor in micro mechanical and electrical structure that sound performance is good, practicality is good from different approach.At first, we discharge wherein stress by form ripple on vibrating diaphragm, can discharge its internal stress because have the silicon base vibrative membrane of shallow corrugated structure in manufacturing process, thus the mechanical sensitivity of raising vibrating diaphragm and reduce its unsteadiness.Compare with traditional plate diaphragm, the shallow corrugated vibrating diaphragm has higher sensitivity, especially for the silicon base vibrative membrane of easy generation high residual stress.
Please refer to Fig. 2 to Fig. 4, shallow corrugated vibrating diaphragm 11 edges of the suspension of the capacitance type sound sensor in micro mechanical and electrical structure of the present invention's first embodiment are fixed on the position of substrate 12, and it forms tuning fork structure in fact.Splicing ear 24 is used for described micro electromechanical structure acoustic sensor is connected to external circuit.
Please refer to Fig. 3, is along the profile of the A-A ' direction of Fig. 2 when the back pole plate electrode is positioned at the back pole plate reverse side.Shallow corrugated vibrating diaphragm 11 edges that hang are fixed on an end of substrate 12, and are not fixed at the other end (end 22 promptly suspends) of substrate 12.Internal stress in the shallow corrugated vibrating diaphragm 11 discharges by the ripple on it 20.Internal stress in the shallow corrugated vibrating diaphragm 11 also can further hold 22 to discharge by suspending of shallow corrugated vibrating diaphragm 11.The back pole plate 13 in band sound hole 14 is fixed on the substrate 12 by support end 21.A series of hole 14 is distributed on the back pole plate 13 regularly.Back pole plate electrode 15 is arranged on the reverse side of back pole plate 13, forms air gap 25 between back pole plate 13 and the shallow corrugated vibrating diaphragm 11.Be covered with electrode on the shallow corrugated vibrating diaphragm 11, form electric capacity between shallow corrugated vibrating diaphragm 11 and the back pole plate electrode 15.When sound wave incides on the shallow corrugated vibrating diaphragm 11 by sound hole 14, shallow corrugated vibrating diaphragm 11 will produce vibration with sound wave, cause the capacitance of the electric capacity that formed by back pole plate 13 and shallow corrugated vibrating diaphragm 11 to change.As shown in Figure 4, back pole plate electrode 15 also can be positioned at the front of back pole plate 13.
In Fig. 3 or Fig. 4, the circumference in the sound hole 14 on the back pole plate 13 is provided with a series of through holes 17, and they form by photoetching process.Can select the size and the relative position of these through holes 17, make its " low pass filter ", promptly when external atmosphere pressure slowly changed, the atmospheric pressure that is delivered on the shallow corrugated vibrating diaphragm 11 can discharge by the sound hole 14 of through hole 17 and air gap 25 and back pole plate 13.But its also will stop simultaneously the passing through of acoustic signals of our desired frequency.Set a series of through holes 16 also are to adopt photoetching process to form on the line film circumference on the shallow corrugated vibrating diaphragm 11, hold the expendable material (sacrificial material) of 22 belows in order to discharge suspending of shallow corrugated vibrating diaphragm 11.Back pole plate 13 is provided with a series of stop bit devices 19.When loading bias voltage on shallow corrugated vibrating diaphragm 11 and back pole plate 13, shallow corrugated vibrating diaphragm 11 is in the process of back pole plate 13 motions, and stop bit device 19 can prevent that shallow corrugated vibrating diaphragm 11 from collapsing to back pole plate 13 over-deflection.Stop bit device 19 can be the discontinuous stop bit post that is distributed in a circumference, also can be made into the circulus that is all continuous distribution.
Please refer to Fig. 5 to Fig. 7, the capacitance type sound sensor in micro mechanical and electrical structure of the present invention's second embodiment and first embodiment roughly the same, difference is that mainly shallow corrugated vibrating diaphragm 31 edges of suspension of the capacitance type sound sensor in micro mechanical and electrical structure of second embodiment are fixed on a plurality of positions of substrate 32, therefore when bias voltage increases, when the vibrating diaphragm Oscillation Amplitude increases, bending stress also increases, thereby has kept metastable sensitivity.Splicing ear 44 is used for described capacitance type sound sensor in micro mechanical and electrical structure is connected to external circuit.Fig. 6 is the vertical view of shallow corrugated vibrating diaphragm 31 shown in Figure 5.Back pole plate 33 is provided with some hole 43.These hole 43 is used to form the acoustic filter that filters certain frequency or certain frequency scope.The big I in sound hole 43 is made the diameter unanimity or inconsistent according to the needs of filtering or is distributed by rule.The length of ripple 40 also can change according to the required sensitivity of capacitance type sound sensor in micro mechanical and electrical structure.When having selected the length of suitable ripple 40, when loading bias voltage on the electric capacity of shallow corrugated vibrating diaphragm 31 and back pole plate 33 formation, shallow corrugated vibrating diaphragm 31 can be positioned on the stop bit device 39 rightly.In this case, because the moving area of shallow corrugated vibrating diaphragm 31 is limited by stop bit device 39, the bending stiffness of shallow corrugated vibrating diaphragm 31 can reduce greatly.In fact this reduced " equivalent thickness " of shallow corrugated vibrating diaphragm 31 greatly because of ripple 40.
For capacitance type sound sensor in micro mechanical and electrical structure (microphone), its sensitivity can be calculated by following formula:
Wherein, a is the radius of shallow corrugated vibrating diaphragm, and σ is the residual stress in the shallow corrugated vibrating diaphragm, and h is the thickness of shallow corrugated vibrating diaphragm, and d represents the width of air gap, d
VbRepresent bias voltage V
bUnder the variation of width of air gap.As bias voltage V
bDuring increase, the sensitivity of microphone also increases.Yet it is in actual applications, really not so.Therefore, another kind of selectable scheme is when bias voltage increases, and increases the bending stress in the shallow corrugated vibrating diaphragm.Figure 7 shows that along the profile of the B-B ' line of Fig. 5.When sound imports into, the shallow corrugated vibrating diaphragm will be pushed to back pole plate by acoustic pressure.The result who increases bias voltage is that the shallow corrugated vibrating diaphragm is by further crooked.Because the shallow corrugated vibrating diaphragm is draped, the shallow corrugated vibrating diaphragm will increase its bending stress after being bent from reset condition.This will compensate the sensitivity increase that raises and produce owing to bias voltage.
Claims (9)
1. capacitance type sound sensor in micro mechanical and electrical structure comprises:
One substrate;
Be fixed on the back pole plate that has several hole on the described substrate by support end;
Be suspended on the vibrating diaphragm on the described substrate;
Form air gap between described back pole plate and the vibrating diaphragm, be covered with electrode on the vibrating diaphragm, form electric capacity between vibrating diaphragm and the back pole plate electrode;
It is characterized in that: described vibrating diaphragm is the shallow corrugated vibrating diaphragm, and described back pole plate electrode is arranged at the front or the reverse side of back pole plate, and the vibrating diaphragm edge of suspension is fixed on the position of described substrate.
2. capacitance type sound sensor in micro mechanical and electrical structure as claimed in claim 1 is characterized in that: described back pole plate is provided with the stop bit device that can prevent that described vibrating diaphragm from collapsing to the back pole plate transition shift.
3. capacitance type sound sensor in micro mechanical and electrical structure as claimed in claim 2 is characterized in that: described stop bit device is the circulus that is distributed in the discontinuous stop bit post of a circumference or is all continuous distribution.
4. capacitance type sound sensor in micro mechanical and electrical structure as claimed in claim 1 is characterized in that: the line film circumference on the described shallow corrugated vibrating diaphragm is provided with a series of through holes.
5. capacitance type sound sensor in micro mechanical and electrical structure comprises:
One substrate;
Be fixed on the back pole plate that has several hole on the described substrate by support end:
Be suspended on the vibrating diaphragm on the described substrate:
Form air gap between described back pole plate and the vibrating diaphragm, be covered with electrode on the vibrating diaphragm, form electric capacity between vibrating diaphragm and the back pole plate electrode;
It is characterized in that: described vibrating diaphragm is the shallow corrugated vibrating diaphragm, and described back pole plate electrode is arranged at the front or the reverse side of back pole plate, and the vibrating diaphragm edge of suspension is fixed on a plurality of positions of described substrate.
6. capacitance type sound sensor in micro mechanical and electrical structure as claimed in claim 5 is characterized in that: the size in described sound hole is made the diameter unanimity or inconsistent according to the needs of filtering or is distributed by rule.
7 capacitance type sound sensor in micro mechanical and electrical structure as claimed in claim 5 is characterized in that: described back pole plate is provided with the stop bit device that can prevent that described vibrating diaphragm from collapsing to the back pole plate transition shift.
8. capacitance type sound sensor in micro mechanical and electrical structure as claimed in claim 7 is characterized in that: described stop bit device is the circulus that is distributed in the discontinuous stop bit post of a circumference or is all continuous distribution.
9. capacitance type sound sensor in micro mechanical and electrical structure as claimed in claim 5 is characterized in that: the line film circumference on the described shallow corrugated vibrating diaphragm is provided with a series of through holes.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNB2005100351140A CN100455142C (en) | 2005-06-03 | 2005-06-03 | Capacitance type sound sensor in micro mechanical and electrical structure |
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| Application Number | Priority Date | Filing Date | Title |
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| CNB2005100351140A CN100455142C (en) | 2005-06-03 | 2005-06-03 | Capacitance type sound sensor in micro mechanical and electrical structure |
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| CN1874616A CN1874616A (en) | 2006-12-06 |
| CN100455142C true CN100455142C (en) | 2009-01-21 |
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| CNB2005100351140A Expired - Fee Related CN100455142C (en) | 2005-06-03 | 2005-06-03 | Capacitance type sound sensor in micro mechanical and electrical structure |
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Families Citing this family (13)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP2237571A1 (en) * | 2009-03-31 | 2010-10-06 | Nxp B.V. | MEMS transducer for an audio device |
| CN101572849B (en) * | 2009-04-03 | 2013-04-24 | 瑞声声学科技(深圳)有限公司 | Silica-based microphone |
| EP2239961A1 (en) * | 2009-04-06 | 2010-10-13 | Nxp B.V. | Backplate for microphone |
| CN102244832B (en) * | 2010-05-12 | 2014-07-09 | 歌尔声学股份有限公司 | Capacitance microphone chip |
| US20120328132A1 (en) * | 2011-06-27 | 2012-12-27 | Yunlong Wang | Perforated Miniature Silicon Microphone |
| JP5267627B2 (en) * | 2011-08-30 | 2013-08-21 | オムロン株式会社 | Acoustic sensor and manufacturing method thereof |
| DE102013224718A1 (en) * | 2013-12-03 | 2015-06-03 | Robert Bosch Gmbh | MEMS microphone component and device having such a MEMS microphone component |
| CN104980850B (en) * | 2014-04-10 | 2018-06-12 | 美商楼氏电子有限公司 | Double diaphragm acoustic apparatus |
| US10057689B2 (en) * | 2014-08-26 | 2018-08-21 | Goertek Inc. | Silicon speaker |
| CN106331916A (en) * | 2015-06-16 | 2017-01-11 | 钰太芯微电子科技（上海）有限公司 | Frequency selection device, ultrasonic microphone and terminal equipment |
| JP6809008B2 (en) * | 2016-07-08 | 2021-01-06 | オムロン株式会社 | MEMS structure and capacitance type sensor, piezoelectric type sensor, acoustic sensor having MEMS structure |
| CN112913261A (en) * | 2018-10-23 | 2021-06-04 | ams有限公司 | Sensor with corrugated diaphragm |
| CN110677798A (en) * | 2019-09-09 | 2020-01-10 | 国网湖南省电力有限公司 | Microphone with self-calibration function, calibration method thereof, sound transmission system and sound detection system |
Citations (3)
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| WO1996005711A1 (en) * | 1994-08-12 | 1996-02-22 | The Charles Stark Draper Laboratory, Inc. | Acoustic transducer with improved low frequency response |
| CN1455618A (en) * | 2003-05-23 | 2003-11-12 | 百富非凡机电设备（北京）有限公司 | Loudspeaker vibrating diaphragm base material structure and manufacturing method thereof |
| CN1505438A (en) * | 2002-12-02 | 2004-06-16 | 佳乐电子股份有限公司 | Capacitor type microphone and micro-electromechanical processing and manufacturing method thereof |
-
2005
- 2005-06-03 CN CNB2005100351140A patent/CN100455142C/en not_active Expired - Fee Related
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO1996005711A1 (en) * | 1994-08-12 | 1996-02-22 | The Charles Stark Draper Laboratory, Inc. | Acoustic transducer with improved low frequency response |
| CN1505438A (en) * | 2002-12-02 | 2004-06-16 | 佳乐电子股份有限公司 | Capacitor type microphone and micro-electromechanical processing and manufacturing method thereof |
| CN1455618A (en) * | 2003-05-23 | 2003-11-12 | 百富非凡机电设备（北京）有限公司 | Loudspeaker vibrating diaphragm base material structure and manufacturing method thereof |
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