WO2012039074A1 - Capteur - Google Patents

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Publication number
WO2012039074A1
WO2012039074A1 PCT/JP2011/000893 JP2011000893W WO2012039074A1 WO 2012039074 A1 WO2012039074 A1 WO 2012039074A1 JP 2011000893 W JP2011000893 W JP 2011000893W WO 2012039074 A1 WO2012039074 A1 WO 2012039074A1
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WIPO (PCT)
Prior art keywords
amplifier
electrode
sensor
capacitance
capacitive element
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PCT/JP2011/000893
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English (en)
Japanese (ja)
Inventor
木村教夫
政井茂雄
中野西保弘
中山和也
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パナソニック株式会社
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Publication of WO2012039074A1 publication Critical patent/WO2012039074A1/fr

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    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; DEAF-AID SETS; PUBLIC ADDRESS SYSTEMS
    • H04R19/00—Electrostatic transducers
    • H04R19/04—Microphones

Definitions

  • the technology disclosed in this specification relates to a sensor such as a microphone that is a sound collection device.
  • Capacitance units constituting these sensors output an electrical signal based on vibrations and displacements of the counter electrodes arranged in the capacitance unit using electrostatic energy as a mediation.
  • the condenser microphone and the pressure sensor are sensors that detect vibration of the counter electrode, and the acceleration sensor is a sensor that detects vibration. These sensors can be connected to an amplifier that reads a signal output from the element capacitor.
  • the above-described element capacitance unit includes a vibration film having a movable electrode that vibrates by sound pressure, and the movable electrode. And a fixed electrode facing each other.
  • the signal output from the element capacitor is about 3 mV to 10 mV in voltage, and is a very weak signal. This signal is read by an amplifier.
  • Patent Document 1 As one of the factors that limit the sensitivity performance, there is a parasitic capacitance generated in the capacitive element section (Patent Document 1).
  • the connection loss C LOSS (unit [F]) due to the parasitic capacitance is expressed by the following equation (1) (see Non-Patent Document 1).
  • C LOSS C m / (C m + C p + C i ) (1)
  • C m is the capacitance [F] of the element capacitance section
  • C p is the parasitic capacitance [F] of the element capacitance section
  • C i is the input capacitance [F] of the amplifier. From the equation (1), it can be seen that the value of the connection loss C LOSS is 1 or less due to the parasitic capacitance or the like, resulting in loss.
  • Patent Document 1 discloses a means for structurally reducing the parasitic capacitance C p of the element capacitance section represented by the equation (1).
  • Patent Document 1 can reduce the parasitic capacitance C p of the element capacitance section, it cannot be eliminated, and the input capacitance C i of the amplifier is not considered.
  • the capacitance C m In the element capacitance portion increasingly smaller also becomes 1 [pF] extent, parasitic capacitance effect is increased to provide a signal reading loss, major challenge when the input capacitance of the amplifier increases the sound pressure sensitivity It has become.
  • the present invention has been made in view of the above technical problems, and an object thereof is to provide a highly sensitive sensor in which the influence of parasitic capacitance and input capacitance is reduced.
  • a sensor includes a first capacitance change detection unit including a first electrode including a movable part, and a second electrode disposed to face the first electrode, and an inverting input terminal.
  • An amplifier having a non-inverting input terminal and an output terminal, and a first capacitive element, wherein the first capacitance change detection unit and the first capacitive element include the inverting input terminal of the amplifier and the first capacitive element.
  • the amplifier is connected in series with the output terminal to form a feedback capacitor of the amplifier.
  • the first electrode or the second electrode is connected to the inverting input terminal of the amplifier, and the first capacitive element is connected to the output terminal of the amplifier.
  • V mic V m ⁇ (1 + C P11 / C 1 ) (2)
  • V m is the open sound pressure sensitivity [V / Pa] of the first capacitance change detection unit
  • C 1 is the capacitance [F] of the first capacitance element.
  • the value of (1 + C P11 / C 1 ) is 1 or more, and even if the parasitic capacitance C P11 exists, there is no loss expressed by the equation (1), and the parasitic capacitance C P11 Due to this, a gain is generated. Therefore, it can be seen that the above-described configuration is a preferable configuration for high sensitivity with reduced connection loss.
  • a second capacitive element connected to a node between the first capacitive change detecting unit and the first capacitive element may be further provided.
  • V mic V m ⁇ ⁇ 1+ (C P11 + C EXT ) / C 1 ⁇ (3)
  • Equation (3) the sensitivity of the sensor can be easily changed by changing the capacitance of the second capacitive element.
  • the first capacitive element may be a second capacitance change detection unit having a third electrode including a movable part and a fourth electrode disposed to face the third electrode. Good.
  • Equation (4) it is preferable that the output of the capacitance change detection unit can be added and subtracted. Subtraction is possible by making the connection opposite to addition. In this case, addition / subtraction of the open output voltage Vm2 of the second capacitance change detection unit can be eliminated.
  • V mic V m2 + V m ⁇ ⁇ 1+ (C P11 + C P22 ) / C m2 ⁇ (4)
  • C P22 is the capacitance value of the parasitic capacitance on the third electrode side of the second capacitance change detecting unit
  • C m2 is the value of the capacitance generated in the third electrode and the fourth electrode.
  • a feedback resistor is further provided between the output terminal and the inverting input terminal of the amplifier. This feedback resistor suppresses saturation of the amplifier.
  • a dielectric film may be provided on the first electrode or the second electrode.
  • the dielectric film may be an electret film. According to this configuration, driving can be performed without external charge supply (polarization voltage). For this reason, a connection line for applying a polarized DC voltage to the element unit is not required, and both electrode terminals of the first capacitance change detecting unit are terminals that do not have connection restrictions to the externally polarized DC voltage. The same connection as a two-terminal passive capacitor is possible.
  • the sensor when an amplifier that reads a signal is connected to the first capacitance change detection unit, even if the parasitic capacitance of the first capacitance change detection unit or the input capacitance of the amplifier exists, Connection loss can be reduced as compared to the conventional case.
  • FIG. 1 is a schematic circuit diagram showing a MEMS condenser microphone according to a first embodiment of the present invention.
  • FIG. 2 is a cross-sectional view of the MEMS element portion which is the first capacitance change detecting portion according to the first embodiment.
  • 3A and 3B are circuit diagrams schematically showing the MEMS element section according to the first embodiment.
  • FIG. 4 is a schematic circuit diagram showing a MEMS capacitor microphone according to a first modification of the first embodiment.
  • FIG. 5 is a schematic circuit diagram showing a MEMS capacitor microphone according to a second modification of the first embodiment.
  • FIGS. 6A to 6D are views showing an overview of the MEMS capacitor microphone according to the first embodiment and the first modification thereof mounted on a printed circuit board.
  • FIGS. 7A to 7D are views showing an overview of a MEMS condenser microphone according to a second modification of the first embodiment mounted on a printed circuit board.
  • a capacitor microphone is described as an example of the sensor, but the following structure may be used for a sensor that detects a physical quantity other than sound pressure, such as a pressure sensor or an acceleration sensor.
  • the capacitance change detection unit of the condenser microphone is a MEMS element unit, and in particular, a MEMS element unit having an electret film.
  • the MEMS element portion refers to a capacitor formed using a semiconductor process, as will be described later.
  • the MEMS element portion may be an assembly type, or an element portion formed by a method other than this may be used instead of the MEMS element portion. The above can be said to be common to all the embodiments and modifications.
  • FIG. 1 is a schematic circuit diagram showing a sensor (MEMS condenser microphone) according to a first embodiment of the present invention.
  • the MEMS capacitor microphone 10 of the present embodiment includes a first capacitance change detecting unit 100, an amplifier 120, a capacitive element 20, and a feedback resistor 30.
  • the first capacitance change detection unit 100 is a MEMS element unit that includes an electrode 101 that is an electrode having a movable part, and an electrode 102 that is disposed to face the electrode 101.
  • the electrode 101 includes, for example, a polysilicon film 91 and an electret film 103, as will be described later. Note that parasitic capacitances 109 and 110 are generated in the first capacitance change detection unit 100 as described later.
  • the electrode 101 of the first capacitance change detection unit 100 is connected to the terminal 21 of the capacitive element 20.
  • the electrode 102 of the first capacitance change detection unit 100 is connected to one end of the feedback resistor 30 and an inverting input terminal (inverting input unit) 121 of the amplifier 120.
  • the inverting input terminal 121 has an input capacitor 125 (capacitor is C i ) of the amplifier 120.
  • the other terminal 22 of the capacitive element 20 is connected to the output terminal (output unit) 123 of the amplifier 120. That is, the first capacitance change detection unit 100 and the capacitive element 20 are connected in series between the inverting input terminal 121 and the output terminal 123 of the amplifier 120 to form a feedback capacitance.
  • the feedback resistor 30 is interposed between the inverting input terminal 121 and the output terminal 123 of the amplifier 120. That is, the feedback resistor 30 is connected in parallel with the first capacitance change detection unit 100 and the capacitive element 20 when viewed from the output terminal 123.
  • the terminal 40 is a power supply terminal for supplying a power supply voltage to the amplifier 120, and the terminal 50 is a reference potential terminal, which is connected to the ground (ground) here.
  • the non-inverting input terminal 122 of the amplifier 120 is connected to a reference potential.
  • FIG. 2 is a cross-sectional view of the MEMS element portion which is the first capacitance change detecting portion according to the first embodiment.
  • the MEMS element portion is formed by finally dividing a large number of microphone chips simultaneously manufactured on a silicon substrate (silicon wafer) using a CMOS (complementary field effect transistor) manufacturing process technology.
  • CMOS complementary field effect transistor
  • the MEMS element unit that is the first capacitance change detection unit 100 includes, for example, an n-type silicon substrate 150, a silicon oxide film (insulating film) 105 formed on the silicon substrate 150, and an oxidation
  • the electrode 102 is disposed so as to face the electrode 101 (polysilicon film 91).
  • a part of the spacer 104 is also formed on the polysilicon film 91.
  • the silicon substrate 150 is formed with a through hole 106 formed by etching or the like.
  • the shape of the through-hole 106 when viewed from the front may be a circle or a polygon such as a quadrilateral.
  • the electrode 101 includes a polysilicon film 91 containing n-type impurities and an electret film 103 formed on a surface of the polysilicon film 91 that faces the electrode 102.
  • the polysilicon film 91 and the electret film 103 are formed so as to cover the through hole 106.
  • a portion of the electrode 101 that is not fixed (fixed) to the silicon oxide film 105 becomes a movable portion.
  • the entire portion of the electret film 103 and the polysilicon film 91 that covers the through hole 106 are mainly movable parts.
  • a portion of the electrode 101 supported by the silicon oxide film 105 is a fixed portion that is not a movable portion.
  • the electret film 103 is made of, for example, an electret silicon oxide film.
  • the electrode 101 may have a stacked structure of the polysilicon film 91 and the electret film 103, or may have a structure in which a silicon nitride film is further stacked.
  • the film thicknesses of the polysilicon film 91 and the electret film 103 are, for example, about 300 nm and 900 nm, respectively.
  • the electrode 102 is made of, for example, a polysilicon film containing an n-type impurity, and is provided with a plurality of holes 107 for allowing sound pressure to pass therethrough.
  • the electrode 102 may also have a stacked structure in which a silicon nitride film is further formed.
  • the electrode 101 which is an electrode having a movable part can be referred to as a “vibrating film” or a “movable film”.
  • the electrode 102 is fixed so that a space (air gap) G is formed between the electrode 102 and the electrode 101.
  • the spacer 104 is formed with a contact hole H for electrical connection with the electrode 101 (polysilicon film 91).
  • the air gap G is originally formed by etching and removing a part of the spacer 104 by a method using a semiconductor fine processing technique such as wet etching, but may be formed by another method.
  • the MEMS element unit functions as a capacitance change detection unit of the condenser microphone by causing the sound wave to vibrate the vibration film including the electrode 101 and the like.
  • the electrode 101 and the electrode 102 which are a pair of electrodes function as a capacitor. That is, in the MEMS element portion, the vibration film is vibrated by the sound wave, and the sound pressure can be detected by detecting the capacitance change caused by the vibration film.
  • the electret film 103 can hold charges. Note that electretization such as corona discharge may be performed at the wafer level, and then the wafer may be divided into chips. Although depending on the properties of the electret film, the electret film is generally charged with a negative charge in many cases.
  • the electret film 103 is composed of an inorganic film such as a silicon oxide film or a silicon nitride film, compared to an electret film using a polymer film such as tetrafluoroethylene / hexafluoropropylene copolymer (FEP).
  • FEP tetrafluoroethylene / hexafluoropropylene copolymer
  • the charge retention characteristics are not easily deteriorated even when exposed to high temperatures, and it is preferably used for a microphone that is mounted by solder reflow.
  • the electret film 103 may be replaced with a polymer film or the like.
  • 3A and 3B are circuit diagrams schematically showing the MEMS element section according to the first embodiment.
  • the electrode 101 having the electret film 103 has ⁇ Q 1 [C] as the charge on the electrode 101 side, and the electrode 102 which is the counter electrode has + Q 1 [C] as the induced charge on the electrode 102 side. C] appears and is in equilibrium.
  • the capacitance C m formed by the electrode 101 and the electrode 102 depends on the length and the electrode area of the air gap G, a value expressed by the following equation.
  • ⁇ 0 the dielectric constant of vacuum and is 8.85 ⁇ 10 ⁇ 12 [F / m].
  • ⁇ s is the relative permittivity of air and is 1.000586.
  • S dia is the area (diaphragm area) [m 2 ] of the overlapping portion of the electrode 101 and the electrode 102.
  • d is the length of the air gap G (gap length) [m].
  • a sinusoidal wave single angle frequency omega s is the guided to the electrode 101 is a movable electrode, the electrode 101 is sinusoidal oscillation at the same frequency as the sound wave.
  • the magnitude of this minute vibration displacement is largely determined by the rigidity (stiffness) of the diaphragm.
  • This minute charge change is also expressed as a minute voltage change V m , Electrode 101 of the voltage: + ⁇ q s sin ( ⁇ s t) / C m Electrode 102 of the voltage: - ⁇ q s sin ( ⁇ s t ) / C m It becomes.
  • the capacitor since the capacitor has a floating structure, a specific parasitic capacitance depending on the structure is generated in the first capacitance change detecting unit 100 as shown in FIGS. 3 (a) and 3 (b). As shown in FIGS. 3A and 3B, a parasitic capacitance 110 is generated between the electrode 101 and the silicon substrate 150. In addition, a parasitic capacitance 109 is generated between the electrode 102 and the silicon substrate 150. These parasitic capacitances are due to fixed objects such as support frames for the electrodes 101 and 102 and electrode leads. The parasitic capacitance does not change with sound waves or vibrations. Therefore, no fluctuating charge (voltage) is generated as a signal at these capacitance ends.
  • FIG. 3 (a) shows a model paying attention to electric charge
  • FIG. 3B shows a model paying attention to voltage change (electromotive force).
  • the capacitance of the capacitance change detection unit is represented by C m and the parasitic capacitances 109 and 110 are represented by C p1 and C P2 , respectively.
  • the parasitic capacitance is a capacitance generated due to the peculiarity of the structure, so that it does not vibrate with sound waves, and no charge is generated in these two capacitances. That is, no electromotive force due to sound pressure is generated in the parasitic capacitors 109 and 110.
  • DC bias condenser microphones were manufactured by E.I. C. Since being devised by Wente, it has a basic configuration and structure in which a polarized DC voltage is applied to one of the electrodes. Therefore, in a general DC bias condenser microphone, the number of terminals that can be used for signal reading is limited to one terminal.
  • G. M.M. Sessler converted a polytetrafluoroethylene film into an electret and applied it to a condenser microphone, which was introduced as an electret condenser microphone.
  • a condenser microphone Today, it is widely used in mobile phones and the like.
  • Many of these electret condenser microphones have a structure in which component elements are mechanically stacked in a cylindrical metal case and the mechanical shape is maintained by mechanical caulking, and one terminal is necessarily connected to the case. In contact. For this reason, in many electret condenser microphones, the number of terminals that can be used for signal reading is limited to one terminal like the DC bias condenser microphone.
  • the condenser microphone according to the present embodiment is similar to the above-described DC bias condenser microphone or the electret condenser microphone that requires mechanical caulking when reading the signal charge or electromotive force generated at both electrodes of the capacitance change detection unit.
  • the amplifier 120 it is preferable to use an operational amplifier type amplifier having an extremely large open loop gain and an extremely small output impedance. When such an amplifier is used, a virtual short circuit occurs at the inverting input terminal, and the contribution of the parasitic capacitance 109 and the input capacitance 125 can be ignored.
  • the parasitic capacitance CP12 at the end of the electrode 102 of the first capacitance change detecting unit 100 connected to the inverting input terminal 121 of the amplifier 120 and the input capacitance 125 (C of the amplifier) i ) uses an amplifier 120 having a very large open loop gain, for example, a gain of 1 ⁇ 10 5 or more, like an operational amplifier, thereby causing a virtual short circuit at the inverting input terminal. Since the non-inverting input terminal 122 of the amplifier 120 is connected to a reference potential (for example, ground), the inverting input terminal 121 becomes a virtual ground. For this reason, the parasitic capacitance of the terminal of the capacitance change detection unit connected to the inverting input terminal 121 and the input capacitance of the amplifier do not contribute to signal reading.
  • a reference potential for example, ground
  • One terminal 22 of the capacitive element 20 is connected to the output terminal 123 of the amplifier 120, and the parasitic capacitance 110 at the connection point between the other terminal 21 of the capacitive element 20 and the electrode 101 end of the first capacitance change detecting unit 100 is , The parasitic capacitance CP11 in the first capacitance change detection unit 100.
  • Expression (2) the term corresponding to Expression (1) is (1 + C P11 / C 1 ), and the value of this term is 1 or more. Therefore, no loss represented by the formula (1) the parasitic capacitance C P11 exists, the gain is caused by the presence of the parasitic capacitance C P11.
  • the MEMS condenser microphone 10 of the present embodiment has a configuration preferable for high sensitivity with no connection loss, and has a configuration in which the input capacitance of the amplifier 120 hardly affects the output. For this reason, even if the MEMS condenser microphone 10 of the present embodiment is downsized, sufficient sound pressure sensitivity can be ensured.
  • connection direction of the first capacitance change detection unit 100 so that the electrode 101 is connected to the inverting input terminal 121 and the electrode 102 is connected to the capacitive element 20, an output voltage whose phase is inverted is obtained. be able to.
  • the feedback resistor 30 is provided as a discharge resistor that prevents the output voltage of the amplifier 120 from being saturated.
  • the electret film 103 may be made of, for example, a dielectric material. However, since the electret film 103 is electretized, it can be driven without external charge supply (polarization voltage). For this reason, the connection line for giving a polarization direct-current voltage to an element part is not required. Both electrode terminals of the first capacitance change detection unit 100 are terminals that are not restricted in connection to the externally polarized DC voltage, and can be connected in the same manner as a normal two-terminal capacitive element.
  • the first element unit 100 is a MEMS element, it is possible to form a semiconductor wafer and to realize a small microphone with uniform microphone characteristics.
  • FIG. 4 is a schematic circuit diagram showing a MEMS capacitor microphone according to a first modification of the first embodiment.
  • the capacitance change detection unit of the MEMS capacitor microphone 11 according to this modification is the same as the MEMS element unit in the MEMS capacitor microphone 10 of the first embodiment shown in FIG. 1, and in particular, a MEMS element having an electret film. Will be described below.
  • the configuration of the amplifier 120 is the same as that of the amplifier shown in FIG.
  • the MEMS condenser microphone 11 of this modification has a configuration in which a capacitive element 60 is added to the MEMS condenser microphone 10 shown in FIG.
  • the capacitive element 60 includes an electrode (terminal 61) connected to a reference potential (for example, ground) and an electrode (terminal 62) connected to a node between the electrode 101 and the electrode (terminal 21) of the capacitive element 20. It is configured. That is, the terminal 62 is connected to a connection point between the terminal 21 and the first capacitance change detection unit 100, and the parasitic capacitance 110 and the capacitive element 60 of the first capacitance change detection unit 100 are viewed from the output terminal 123. Are connected in parallel.
  • V mic V m ⁇ ⁇ 1+ (C P11 + C EXT ) / C 1 ⁇ (3)
  • the sensitivity can be easily changed without changing the configuration of the first capacitance change detection unit 100 by appropriately changing the capacitance of the capacitive element 60. Be able to.
  • a laser trimmable capacitor having one end connected to the ground potential as the parasitic capacitance CP11 of the first capacitance change detecting unit 100 as the capacitive element 60, because the sensitivity can be adjusted more accurately.
  • the amplifier 120 and the capacitive element 20 may be formed on one integrated circuit (IC) chip. With this configuration, the microphone can be reduced in size.
  • IC integrated circuit
  • the capacitive element 60 may also be formed on the same IC chip as the amplifier 120 and the capacitive element 20. In this way, the microphone can be further reduced in size.
  • the capacitive element 60 is preferably realized as several cell type sheet capacitive elements on the IC, and a configuration in which the capacitance is changed by wiring as a series-parallel connection structure is preferable because sensitivity can be easily adjusted.
  • FIG. 5 is a schematic circuit diagram showing a MEMS capacitor microphone according to a second modification of the first embodiment.
  • the capacitance change detection unit of the MEMS condenser microphone 12 according to this modification is the same as the MEMS element unit in the MEMS capacitor microphone 10 of the first embodiment shown in FIG. 1, and in particular, a MEMS element having an electret film. Will be described below.
  • the configuration of the amplifier 120 is the same as that of the amplifier shown in FIG.
  • the MEMS capacitor microphone 12 is the same as the MEMS capacitor microphone 10 shown in FIG. 1, except that a second capacitance change detection unit 200 is provided instead of the capacitor element 20.
  • the second capacitance change detection unit 200 is a MEMS element having the same configuration as that of the first capacitance change detection unit 100, and includes an electrode 201 connected to the output terminal 123 of the amplifier 120, and a first capacitance change detection. And electrode 202 connected to part 100 (electrode 101). Parasitic capacitances 209 and 210 are generated in the second capacitance change detection unit 200.
  • the electrode 201 has a movable part and an electret film 203.
  • the electrode 201 of the second capacitance change detection unit 200 is connected to the output terminal 123 of the amplifier 120. Therefore, when the amplifier 120 having an extremely low output impedance such as an operational amplifier is used, the impedance of the parasitic capacitance 210 can be ignored, and the parasitic capacitance 210 of the second capacitance change detecting unit 200 can read the signal. No longer contributes.
  • the output voltage of the MEMS condenser microphone 12 is expressed by the following formula (4).
  • the open output voltage V m2 of the second capacitance change detection unit 200 can be added and subtracted without loss.
  • V mic V m2 + V m ⁇ ⁇ 1+ (C P11 + C P22 ) / C m2 ⁇
  • CP 22 is a capacitance value of the parasitic capacitance 210 on the electrode 201 side
  • C m2 is a capacitance generated between the electrode 201 and the electrode 202. From the equation (4), it can be seen that the MEMS capacitor microphone 12 of the present modification has a configuration in which the addition of the open electromotive force of each capacitance change detection unit can be added with a gain by the parasitic capacitance without loss.
  • connection direction of either one of the first capacitance change detection unit 100 and the second capacitance change detection unit 200 can be changed.
  • the subtraction reduces the vibration noise signal. There is an advantage that a signal of only the subtracted sound signal can be taken out.
  • the size of the feedback resistor 30 is the same as that of the microphone.
  • the low frequency of the use band is set to fl [Hz]
  • Rf [ ⁇ ] is the size of the feedback resistor 30.
  • the MEMS capacitor microphone 12 shown in FIG. 5 can be operated as a microphone even if the first capacitance change detection unit 100 is replaced with the capacitive element 20 (capacitance C 1 ) shown in FIG. Even in this case, since the output from the amplifier 120 is not affected by the input capacitance Ci of the amplifier 120, the same effect as the MEMS capacitor microphone 10 according to the first embodiment can be obtained.
  • FIGS. 6A to 6D are views showing an overview of the MEMS capacitor microphone according to the first embodiment and the first modification thereof mounted on a printed circuit board.
  • 6A is a plan view of the microphone (module) with the metal cap removed
  • FIG. 6B is a cross-sectional view of the microphone (module)
  • FIG. 6C is with the cap attached.
  • FIG. 6D is a top view (right side) and a side view (left side) of the state
  • FIG. 6D is a bottom view.
  • the MEMS condenser microphone of the present embodiment has a first capacitance change detection in a container 300 composed of a printed board 301 and a metal cap (lid body) 302.
  • the IC 330 provided with the unit 303 and the amplifier 120 is accommodated.
  • the IC 330 is obtained by integrating the capacitive elements 20 and 60 and the feedback resistor 30 shown in FIGS. 1 and 2 on the chip together with the amplifier 120.
  • an opening (sound hole) 306 for introducing sound is provided in the printed board 301.
  • an opening (sound hole) for introducing sound may be provided in the metal cap 302 instead of the opening 306 in the printed board 301.
  • a voltage is supplied to the output terminal 123 of the amplifier 120 and the amplifier 120 (see FIG. 1) on the surface opposite to the surface on which the first capacitance change detection unit 303 and the IC 330 are mounted on the printed circuit board 301.
  • the voltage supply terminal (power input terminal) 40 and the grounding terminal 50 are arranged to constitute a surface mount terminal structure. These terminals serve as interface terminals with external devices, and the MEMS capacitor microphone of the present embodiment is a surface mountable microphone.
  • the printed circuit board 301 and the metal cap 302 are coupled to each other by solder reflow or the like and have the same potential.
  • the first capacitance change detection unit 303 and the IC 330 are adhesively mounted on one main surface of the printed circuit board 301 with an adhesive, and the two pads 304 and 305 of the first capacitance change detection unit 303 are respectively provided.
  • the input pads 336 and 338 of the IC 330 are connected by wire bonding.
  • the IC 330 includes the above-described operational amplifier type amplifier 120 formed of CMOS, and is provided with a power supply pad 334, a GND pad 335, input pads 336 and 338, and an output pad 337.
  • the power supply pad 334 and the GND pad 335 are connected to respective relay pads on one main surface of the printed circuit board 301 by wire bonding, and are connected to the other main surface of the printed circuit board 301 through a through hole or an inner via of the printed circuit board 301. Connected to terminals 40 and 50, respectively.
  • the output of the amplifier 120 is transmitted from the output pad 337 to the relay pad on one main surface of the printed circuit board 301, and transmitted to the output terminal 123 on the other main surface of the printed circuit board 301 through the through hole or inner via of the printed circuit board 301. Is done.
  • the ground terminal 50 is electrically connected to the metal cap 302 through the printed board 301, and the container 300 becomes a shield container having a ground potential for protecting the inside of the container from electromagnetic noise from the outside.
  • the first capacitance change detection unit 303 has a size of about 2 mm square and the IC 330 has a size of about 0.7 mm square, 4 mm (width) shown in FIGS.
  • a small surface-mount microphone having a size of about x5 mm (depth) x1.3 mm (height) can be configured.
  • the first capacitance change detection unit 303, the amplifier 120, and the like are housed in a container 300 composed of a printed board 301 and a metal cap (lid body).
  • the influence of noise is reduced, the connection loss is small, and the output is high quality. Further, no external parts are required, and the size can be reduced.
  • a cap made of a material other than metal may be used instead of the metal cap 302.
  • electromagnetic noise can be prevented from entering from outside the container.
  • the microphone can be further reduced in size.
  • the feedback resistor 30 can also be formed on the IC 330.
  • FIGS. 7A to 7D are views showing an overview of a MEMS condenser microphone according to a second modification of the first embodiment mounted on a printed circuit board.
  • 7A is a plan view of the microphone (module) with the metal cap removed
  • FIG. 7B is a cross-sectional view of the microphone (module)
  • FIG. 7C is attached with the cap.
  • FIG. 7 is a top view (right side) and a side view (left side) of the state
  • FIG. 7 (d) is a bottom view.
  • the MEMS condenser microphone according to this modification is provided with a first capacitance change in a container 400 composed of a printed board 401 and a metal cap (lid body) 402.
  • the IC 430 provided with the detection unit 403, the second capacitance change detection unit 404, and the amplifier 120 is housed.
  • the IC 430 is obtained by integrating the feedback resistor 30 shown in FIG.
  • openings (sound holes) 406 and 407 for introducing sound are provided in the printed circuit board 401.
  • the opening (sound hole) for introducing sound may be provided in the metal cap 402 without providing the openings 406 and 407.
  • the output terminal of the amplifier 120 (see FIG. 5) is provided on the surface of the printed circuit board 401 opposite to the surface on which the first capacitance change detection unit 403, the second capacitance change detection unit 404, and the IC 430 are mounted.
  • a voltage supply terminal (power input terminal) 40 for supplying a voltage to the amplifier 120, and a ground terminal 50 are arranged to constitute a surface-mount terminal structure. These terminals serve as interface terminals with an external device, and the MEMS capacitor microphone according to this modification is a surface mountable microphone.
  • the printed circuit board 401 and the metal cap 402 are coupled by solder reflow or the like and have the same potential.
  • the first capacitance change detection unit 303, the second capacitance change detection unit 404, and the IC 430 are adhesively mounted on one main surface of the printed circuit board 401 with an adhesive, and the first capacitance change detection unit 303 is mounted.
  • the second capacitance change detector 404 and the IC 430 are connected by wire bonding.
  • the operational amplifier type amplifier 120 composed of the above-described CMOS is formed, and a power supply pad 434, a GND pad 435, an input pad 436, and an output pad 437 are provided.
  • the power supply pad 434 and the GND pad 435 are connected to respective relay pads on one main surface of the printed circuit board 401 by wire bonding, and terminals on the other main surface of the printed circuit board 401 through through holes or inner vias of the printed circuit board 401. 40 and 50, respectively.
  • the output of the amplifier 120 is transmitted from the output pad 437 to a relay pad on one main surface of the printed circuit board 401 and connected to the output terminal 123 on the other main surface of the printed circuit board 401 through a through hole or an inner via of the printed circuit board 401. Is done.
  • the pad 414 of the first capacitance change detection unit 403 is the input pad 436 of the IC 430
  • the other pad 415 is the pad 425 of the second capacitance change detection unit 404
  • the pad 424 of the second capacitance change detection unit 404 is
  • Each of the printed circuit boards 401 is connected to the output pad 437 of the IC 430 through a relay pad on one main surface by wire bonding.
  • the ground terminal 50 is electrically connected to the metal cap 402 through the printed circuit board 401, and the container 400 becomes a shield container having a ground potential that protects the inside of the container from electromagnetic noise from the outside.
  • the first capacitance change detection unit 403 and the second capacitance change detection unit 404 have a size of about 2 mm square, and the IC 430 has a size of about 0.7 mm square, 4 mm ( A small surface-mount microphone having a width of about 8 mm (depth) x 1.3 mm (height) can be configured.
  • the distance between the two openings 406 and 407 is within 4 mm. If the interval between the two openings 406 and 407 is within 4 mm, the difference in the magnitude of the incident sound pressure between the opening 406 and the opening 407 is 1 at a sound source distance of 50 cm at a frequency of an audio frequency of 10 kHz or less with a wavelength of 34 mm. % Or less, and the characteristics of the microphone shown in the formula (4) are not impaired.
  • the microphones according to the embodiments of the present invention and the modified examples thereof are useful for various communication devices and the like as microphones having a small connection loss with an amplifier even if there is a parasitic capacitance.

Landscapes

  • Physics & Mathematics (AREA)
  • Engineering & Computer Science (AREA)
  • Acoustics & Sound (AREA)
  • Signal Processing (AREA)
  • Electrostatic, Electromagnetic, Magneto- Strictive, And Variable-Resistance Transducers (AREA)
  • Circuit For Audible Band Transducer (AREA)
  • Micromachines (AREA)
  • Pressure Sensors (AREA)

Abstract

L'invention concerne un capteur, le capteur comprenant une première électrode (101) comportant également une partie mobile et une deuxième électrode (102) placée en regard de la première électrode (101) et comportant : une première unité de détection de variation de capacité (100) conçue pour détecter une grandeur physique à partir d'une variation de capacité ; un amplificateur (120) possédant une borne d'entrée inverseuse (121) ; et un premier élément condensateur (20). La première unité de détection de variation de capacité (100) et le premier élément condensateur (20) sont montés en série entre la borne d'entrée inverseuse (121) et une borne de sortie (123) de l'amplificateur (120) et forment une capacité de réaction pour l'amplificateur (120).
PCT/JP2011/000893 2010-09-22 2011-02-17 Capteur WO2012039074A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
JP2010211711A JP2012070120A (ja) 2010-09-22 2010-09-22 センサ
JP2010-211711 2010-09-22

Publications (1)

Publication Number Publication Date
WO2012039074A1 true WO2012039074A1 (fr) 2012-03-29

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JP (1) JP2012070120A (fr)
WO (1) WO2012039074A1 (fr)

Cited By (1)

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US20150137834A1 (en) * 2012-06-12 2015-05-21 Ams Ag Sensor arrangement and method for generating an amplified sensor signal

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP3262852A4 (fr) * 2015-10-30 2018-03-14 Goertek Inc. Filtre acoustique passe-bande et appareil de détection acoustique

Citations (7)

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Publication number Priority date Publication date Assignee Title
JPH1123609A (ja) * 1997-07-04 1999-01-29 Sumitomo Metal Ind Ltd 静電容量型センサ回路
JP2004007481A (ja) * 2002-03-29 2004-01-08 Sumitomo Metal Ind Ltd 静電容量の検出回路及び検出方法
JP2004506394A (ja) * 2000-08-11 2004-02-26 ノールズ　エレクトロニクス，リミテッド　ライアビリティ　カンパニー 小型ブロードバンド変換器
WO2006033269A1 (fr) * 2004-09-24 2006-03-30 Hosiden Corporation Circuit amplificateur de signal et capteur d’acceleration ayant ledit circuit
JP2008211421A (ja) * 2007-02-26 2008-09-11 Sanyo Electric Co Ltd 静電容量変化検出回路及び半導体装置
JP2008546240A (ja) * 2005-05-16 2008-12-18 センスファブ・ピーティーイー・リミテッド シリコンマイクロフォン
WO2010073598A1 (fr) * 2008-12-24 2010-07-01 パナソニック株式会社 Capteur de type sortie de signal d'équilibrage

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH1123609A (ja) * 1997-07-04 1999-01-29 Sumitomo Metal Ind Ltd 静電容量型センサ回路
JP2004506394A (ja) * 2000-08-11 2004-02-26 ノールズ　エレクトロニクス，リミテッド　ライアビリティ　カンパニー 小型ブロードバンド変換器
JP2004007481A (ja) * 2002-03-29 2004-01-08 Sumitomo Metal Ind Ltd 静電容量の検出回路及び検出方法
WO2006033269A1 (fr) * 2004-09-24 2006-03-30 Hosiden Corporation Circuit amplificateur de signal et capteur d’acceleration ayant ledit circuit
JP2008546240A (ja) * 2005-05-16 2008-12-18 センスファブ・ピーティーイー・リミテッド シリコンマイクロフォン
JP2008211421A (ja) * 2007-02-26 2008-09-11 Sanyo Electric Co Ltd 静電容量変化検出回路及び半導体装置
WO2010073598A1 (fr) * 2008-12-24 2010-07-01 パナソニック株式会社 Capteur de type sortie de signal d'équilibrage

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20150137834A1 (en) * 2012-06-12 2015-05-21 Ams Ag Sensor arrangement and method for generating an amplified sensor signal
US10222407B2 (en) * 2012-06-12 2019-03-05 Ams Ag Sensor arrangement with a capacitive sensor and method for generating an amplified sensor signal with a capacitive sensor
US10823774B2 (en) 2012-06-12 2020-11-03 Ams Ag Sensor arrangement with a capacitive sensor and method for generating an amplified sensor signal with a capacitive sensor

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