WO2011024397A1 - Microphone à condensateur - Google Patents

Microphone à condensateur Download PDF

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Publication number
WO2011024397A1
WO2011024397A1 PCT/JP2010/005012 JP2010005012W WO2011024397A1 WO 2011024397 A1 WO2011024397 A1 WO 2011024397A1 JP 2010005012 W JP2010005012 W JP 2010005012W WO 2011024397 A1 WO2011024397 A1 WO 2011024397A1
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WO
WIPO (PCT)
Prior art keywords
microphone
cover
capacitor structure
base substrate
microphone element
Prior art date
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PCT/JP2010/005012
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English (en)
Japanese (ja)
Inventor
笹倉幸一
加茂正太郎
Original Assignee
スター精密株式会社
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Filing date
Publication date
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Publication of WO2011024397A1 publication Critical patent/WO2011024397A1/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
    • 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
    • H04R19/005—Electrostatic transducers using semiconductor materials
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; DEAF-AID SETS; PUBLIC ADDRESS SYSTEMS
    • H04R31/00—Apparatus or processes specially adapted for the manufacture of transducers or diaphragms therefor
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L2224/00—Indexing scheme for arrangements for connecting or disconnecting semiconductor or solid-state bodies and methods related thereto as covered by H01L24/00
    • H01L2224/01—Means for bonding being attached to, or being formed on, the surface to be connected, e.g. chip-to-package, die-attach, "first-level" interconnects; Manufacturing methods related thereto
    • H01L2224/42—Wire connectors; Manufacturing methods related thereto
    • H01L2224/47—Structure, shape, material or disposition of the wire connectors after the connecting process
    • H01L2224/48—Structure, shape, material or disposition of the wire connectors after the connecting process of an individual wire connector
    • H01L2224/4805—Shape
    • H01L2224/4809—Loop shape
    • H01L2224/48091—Arched
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L2224/00—Indexing scheme for arrangements for connecting or disconnecting semiconductor or solid-state bodies and methods related thereto as covered by H01L24/00
    • H01L2224/01—Means for bonding being attached to, or being formed on, the surface to be connected, e.g. chip-to-package, die-attach, "first-level" interconnects; Manufacturing methods related thereto
    • H01L2224/42—Wire connectors; Manufacturing methods related thereto
    • H01L2224/47—Structure, shape, material or disposition of the wire connectors after the connecting process
    • H01L2224/48—Structure, shape, material or disposition of the wire connectors after the connecting process of an individual wire connector
    • H01L2224/481—Disposition
    • H01L2224/48135—Connecting between different semiconductor or solid-state bodies, i.e. chip-to-chip
    • H01L2224/48137—Connecting between different semiconductor or solid-state bodies, i.e. chip-to-chip the bodies being arranged next to each other, e.g. on a common substrate
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L2924/00—Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
    • H01L2924/10—Details of semiconductor or other solid state devices to be connected
    • H01L2924/102—Material of the semiconductor or solid state bodies
    • H01L2924/1025—Semiconducting materials
    • H01L2924/10251—Elemental semiconductors, i.e. Group IV
    • H01L2924/10253—Silicon [Si]
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L2924/00—Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
    • H01L2924/10—Details of semiconductor or other solid state devices to be connected
    • H01L2924/146—Mixed devices
    • H01L2924/1461—MEMS
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L2924/00—Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
    • H01L2924/30—Technical effects
    • H01L2924/301—Electrical effects
    • H01L2924/3011—Impedance

Definitions

  • the present invention relates to a condenser microphone, and more particularly, to a condenser microphone having a microphone element manufactured using a MEMS (Micro Electro Mechanical Systems) technology.
  • MEMS Micro Electro Mechanical Systems
  • a capacitor microphone has a structure having a capacitor structure in which a diaphragm and a fixed electrode are arranged to face each other.
  • the capacitor structure is formed using MEMS technology.
  • a device for stacking as part of the microphone element has also been devised.
  • a capacitor structure is stacked on a silicon substrate having a central opening so as to close the central opening.
  • a microphone element is configured.
  • the condenser microphone described in FIG. 6 of the above-mentioned “Patent Document 1” has a configuration in which the microphone element is housed in the housing in a state where the microphone element is mounted and fixed on the base substrate together with the impedance conversion element. .
  • the condenser microphone described in FIG. 5 of “Patent Document 2” has a configuration in which the microphone element is housed in a housing in a state of being suspended and fixed to the top substrate together with the impedance conversion element.
  • the capacitor microphone is positioned above the capacitor structure portion on the upper wall of the casing. A sound hole for guiding sound to the capacitor structure is formed.
  • front space a space between the sound hole and the capacitor structure (hereinafter referred to as “front space”) surrounds the front space (hereinafter referred to as “front space”). Since it is formed with a considerably large volume, it has the following problems.
  • the resonance frequency becomes low, so that sound wave resonance occurs in the audible range or a frequency range close to this, and thus the microphone sensitivity is uniform in the audible range. There is a problem that the performance is impaired.
  • the front space and the outer peripheral space may be partitioned at the suspension fixing portion. This can reduce the volume of the front space.
  • the suspension fixing portion of the microphone element serves not only as a suspension fixing function but also as an electrical connection function between the capacitor structure portion and the top substrate. Therefore, the degree of freedom of the shape is small, and therefore the degree of freedom of the volume and shape of the front space is also small, which is insufficient to ensure the uniformity of the microphone sensitivity in the audible range. There is a problem of becoming.
  • the uniformity of the microphone sensitivity in the audible range cannot be ensured. There's a problem.
  • the present invention has been made in view of such circumstances, and in a condenser microphone having a microphone element manufactured using MEMS technology, the microphone element may be mounted and fixed on a base substrate.
  • An object of the present invention is to provide a condenser microphone capable of ensuring uniformity of microphone sensitivity.
  • the above object is achieved by devising a structure for partitioning the front space from the outer peripheral space in the housing.
  • the condenser microphone is A microphone element in which a capacitor structure in which a diaphragm and a fixed electrode are arranged to face each other on a silicon substrate in which a central opening is formed is laminated so as to close the central opening; An impedance conversion element for converting the capacitance of the capacitor structure into an electrical impedance; and A base substrate on which the microphone element and the impedance conversion element are placed and fixed; A cover fixed to the base substrate so as to cover the microphone element and the impedance conversion element, A sound hole for guiding sound to the capacitor structure is formed at a position above the capacitor structure on the upper wall of the cover, Between the upper surface wall of the cover and the microphone element, a sound path wall that partitions a front space between the capacitor structure and the sound hole and an outer peripheral space surrounding the front space is disposed. .
  • the terms indicating the direction such as “upper surface wall” and “upward position” are used for the sake of convenience in order to clarify the positional relationship between the members constituting the condenser microphone.
  • the directionality when actually using the microphone is not limited.
  • the “cover” is a member that forms a casing that covers the microphone element and the impedance conversion element with the base substrate by being fixed to the base substrate, its specific configuration, fixing structure to the base substrate, and the like Is not particularly limited.
  • a specific configuration of the “cover” for example, a metal plate is formed as a single member by press molding, or mounted on the base substrate so as to surround the microphone element and the impedance conversion element. It is possible to employ a member constituted by a fixed annular member and a lid member placed and fixed on the upper surface of the annular member.
  • the “sound road wall” is a member formed so as to partition the front space and the outer peripheral space
  • the specific configuration such as the height and the cross-sectional shape thereof is not particularly limited.
  • the “sound path wall” may be configured as a part of the microphone element, or may be configured as a member different from the microphone element.
  • the condenser microphone according to the present invention has a configuration in which a microphone element in which a capacitor structure is laminated on a silicon substrate is placed and fixed on a base substrate together with an impedance conversion element,
  • the cover fixed to the base substrate so as to cover the microphone element and the impedance conversion element is provided with a sound hole for guiding sound to the capacitor structure portion at a position above the capacitor structure portion on the upper surface wall.
  • the sound path wall that partitions the front space between the capacitor structure and the sound hole and the outer peripheral space surrounding the front space is arranged between the upper surface wall of the cover and the microphone element.
  • the front space and the outer peripheral space are partitioned by the sound path wall in the casing constituted by the base substrate and the cover, the volume of the front space can be reduced.
  • this sound path wall does not require an electrical connection function to the capacitor structure, and the function can be specialized for the partition function between the front space and the outer space, so the volume and shape of the front space The degree of freedom can be increased, which makes it easy to ensure the uniformity of microphone sensitivity in the audible range.
  • the uniformity of the microphone sensitivity is ensured even when the microphone element is mounted and fixed on the base substrate. be able to.
  • the sound path wall is composed of a resist layer stacked on the upper surface of the microphone element, the sound path wall is formed in the step of stacking the microphone element using the MEMS technology. Also, at least a part thereof can be laminated. Therefore, the arrangement of the sound path wall can be performed relatively easily, and the positional accuracy can be increased.
  • the sound path wall is assumed to be composed only of the resist layer, and the resist layer is arranged in a state in which the upper end surface thereof is brought into contact with the upper surface wall of the cover and is compressed and elastically deformed in the vertical direction.
  • the sound path wall is composed only of the resist layer, the entire sound path wall can be simultaneously laminated in the microphone element stacking process, which facilitates the arrangement of the sound path wall. And it can carry out with sufficient position accuracy.
  • the resist layer laminated as the sound path wall is disposed in a state where the upper end surface of the resist layer is in contact with the upper surface wall of the cover and is compressed and elastically deformed in the vertical direction.
  • the front space and the outer peripheral space can be reliably partitioned. At that time, even if there is some variation in the distance between the upper end surface of the microphone element and the upper surface wall of the cover, the partition function can be maintained by the compression elastic deformation action of the resist layer formed as a sound path wall. it can.
  • a part of the sound path wall may be formed of a resist layer, and an elastic member may be interposed between the upper end surface of the resist layer and the upper surface wall of the cover. is there. Even when such a configuration is adopted, the front space and the outer peripheral space can be reliably partitioned.
  • the space located below the capacitor structure (hereinafter referred to as “rear space”) is small, the force required to displace the diaphragm increases, so the diaphragm is difficult to displace. Therefore, the required acoustic characteristics cannot be ensured. Therefore, if the communication hole is formed in at least one of the silicon substrate and the base substrate so that the central opening of the silicon substrate communicates with the outer peripheral space, the volume of the rear space can be sufficiently increased. Thereby, a required acoustic characteristic can be ensured.
  • the front space and the outer space are partitioned by the sound path wall, so that the front space and the rear space communicate with each other through the outer space even if the communication hole is formed. Therefore, there is no risk of disturbing the microphone function.
  • the communication hole is formed by cutting away a part of the lower end portion of the silicon substrate, the communication hole can be formed at the same time in the process of forming the microphone elements. Further, if the communication hole is formed by cutting the upper surface of the base substrate into a concave groove shape, the microphone element stacking process can be simplified.
  • FIG. 4 is a side sectional view showing in detail a microphone element of the condenser microphone, and a sectional view taken along line II-II in FIG. Sectional view along line III-III in Fig. 2 Side sectional view showing the manufacturing process of the microphone element (Part 1) Sectional drawing (the 2) which shows the manufacturing process of the said microphone element Sectional drawing (the 3) which shows the manufacturing process of the said microphone element
  • Part 1 Sectional drawing
  • FIG. 1 which shows the 1st modification of the said embodiment.
  • FIG. 1 which shows the 2nd modification of the said embodiment.
  • FIG. 1 which shows the 3rd modification of the said embodiment.
  • FIG. 1 is a side sectional view showing a condenser microphone 10 according to an embodiment of the present invention in an upwardly arranged state.
  • the condenser microphone 10 includes a microphone element 20, an IC chip 40, a base substrate 50, and a cover 60.
  • the condenser microphone 10 is used in a state where it is surface-mounted on a printed circuit board (not shown) of an external device (for example, a mobile phone) on the lower surface of the base substrate 50.
  • a vibrating membrane 24 and a fixed electrode 26 are disposed opposite to each other on a silicon substrate 22 in which a central opening 22a is formed, and thereby a capacitor structure C is configured.
  • the microphone element 20 of the condenser microphone 10 is manufactured using MEMS technology (this will be described later).
  • the IC chip 40 takes out the change in capacitance between the vibrating membrane 24 and the fixed electrode 26 caused by the vibration of the vibrating membrane 24 as an electric signal by converting the electric impedance, and amplifies the electric signal. Is configured to do.
  • the base substrate 50 has a configuration in which a plurality of conductive layers (not shown) are formed in a predetermined wiring pattern on both upper and lower surfaces of an insulating substrate having a rectangular outer shape having a long side of about 4 mm in plan view. .
  • the base substrate 50 is configured to place and fix the microphone element 20 and the IC chip 40 on the upper surface thereof.
  • the microphone element 20 is mounted and fixed by adhering the microphone element 20 to the upper surface of the base substrate 50 on the lower surface of the silicon substrate 22.
  • the IC chip 40 is mounted and fixed by adhering the IC chip 40 to the upper surface of the base substrate 50 in a state where the IC chip 40 is disposed adjacent to the microphone element 20.
  • attachment is performed using an epoxy-type adhesive agent etc., for example.
  • the IC chip 40 includes a power terminal, an output terminal, a ground terminal, and a bias terminal (not shown).
  • the IC chip 40 has its power supply terminal, output terminal, and grounding terminal electrically connected to each conductive layer formed on the base substrate 50 via bonding wires 42 and its bias.
  • the terminal for use is electrically connected to the terminal portion 32 ⁇ / b> A of the vibrating membrane 24 via the bonding wire 44.
  • terminal portion 32B of the fixed electrode 26 in the microphone element 20 is electrically connected to a grounding conductive layer formed on the base substrate 50 via a bonding wire 46.
  • the cover 60 is placed and fixed on the base substrate 50 so as to cover the microphone element 20 and the IC chip 40.
  • the cover 60 and the base substrate 50 constitute a housing that houses the microphone element 20 and the IC chip 40.
  • the cover 60 is formed by press forming a metal plate.
  • the cover 60 includes an upper surface wall 60A that extends in parallel with the base substrate 50 and a peripheral wall 60B that extends downward from the outer peripheral edge of the upper surface wall 60A.
  • the cover 60 is mounted and fixed on the base substrate 50 by soldering the lower edge of the peripheral wall 60B to the grounding conductive layer formed on the outer peripheral edge of the upper surface of the base substrate 50. It is done by.
  • a sound hole 60a for guiding sound to the capacitor structure C is formed at a position above the capacitor structure C in the upper surface wall 60A of the cover 60.
  • the sound hole 60a has a circular opening shape with a diameter of about ⁇ 0.8 mm.
  • a front space C1 between the capacitor structure C and the sound hole 60a and an outer peripheral space C3 surrounding the front space C1 are partitioned.
  • a cylindrical sound path wall 70 is disposed.
  • the sound path wall 70 is formed to extend in the vertical direction so as to surround the sound hole 60a. At this time, the inner diameter of the sound path wall 70 is set to a value of about ⁇ 1 mm, and the wall thickness thereof is set to a value of about 0.05 to 0.1 mm.
  • the sound path wall 70 is composed of a resist layer formed on the upper surface of the microphone element 20 (this will be described later).
  • FIG. 2 is a side sectional view showing the microphone element 20 in detail
  • FIG. 3 is a sectional view taken along the line III-III in FIG. 2 is a cross-sectional view taken along the line II-II in FIG.
  • the vibration film 24 and the fixed electrode 26 are disposed opposite to each other on the silicon substrate 22 in which the central opening 22a is formed. It is configured.
  • the silicon substrate 22 is composed of a single crystal silicon chip cut out to a size of about 1.6 mm square from a silicon wafer and has a thickness of about 0.4 mm.
  • the central opening 22a of the silicon substrate 22 is formed in a cylindrical shape by etching. At this time, the inner diameter of the central opening 22a is set to about ⁇ 0.9 mm.
  • An insulating layer 28 made of a silicon oxide film is laminated around the central opening 22 a on the upper surface of the silicon substrate 22.
  • a thin insulating layer 36 made of a silicon oxide film is formed on the lower surface of the silicon substrate 22 by a thermal oxidation process.
  • the fixed electrode 26 is made of polycrystalline silicon, and is laminated on the upper surface of the insulating layer 28 so as to close the central opening 22a.
  • a plurality of through holes 26a are formed in the fixed electrode 26 so as to face the central opening 22a.
  • each through hole 26a is suitably 5 to 20 ⁇ m.
  • the reason is as follows. That is, if the hole diameter becomes too small, the acoustic resistance increases, and the vibration of the vibration film 24 tends to be suppressed. On the other hand, if the hole diameter becomes too large, the area of the fixed electrode 26 becomes small, and the vibration film 24 As a result, the area for forming the capacitor structure C is reduced, and as a result, the microphone sensitivity tends to decrease.
  • An insulating layer 30 made of a silicon oxide film is laminated on the upper surface of the fixed electrode 26. At this time, the insulating layer 30 is formed with a circular opening 30a having an inner diameter slightly smaller than that of the central opening 22a, and a through hole 30b is formed around the opening 30a.
  • the optimal thickness of this insulating layer 30 is 2 to 6 ⁇ m.
  • the insulating layer 30 is a layer that determines the gap between the fixed electrode 26 and the vibrating membrane 24.
  • the film thickness is too thin, the viscous resistance between the fixed electrode 26 and the vibrating membrane 24 increases. There is a tendency that a sufficient displacement of the vibration film 24 cannot be obtained.
  • the insulating layer 30 is made too thick, the capacitance of the capacitor structure C is in inverse proportion to the gap, and the microphone sensitivity tends to decrease.
  • a pair of terminal portions 32A and 32B are laminated and formed as conductive layers made of a metal thin film at two locations on the diagonal line on the upper surface of the insulating layer 30. At that time, one terminal portion 32A is formed so that a part thereof is in contact with the upper surface of the vibration film 24, and the other terminal portion 32B is partly provided through the through hole 30b of the insulating layer 30. It is formed so as to contact the fixed electrode 26.
  • Aluminum, chromium / gold, titanium / platinum, or the like is preferably used as the metal to be the terminal portions 32A and 32B.
  • the vibration film 24 is made of polycrystalline silicon, and is disposed in the vicinity of the upper portion of the fixed electrode 26 so as to extend in parallel with the fixed electrode 26. At this time, the vibration film 24 has a circular outer shape slightly larger than the circular opening 30 a of the insulating layer 30, and is laminated on the insulating layer 30 at the outer peripheral edge portion thereof. A plurality of minute through holes 24 a are formed in the center of the vibrating membrane 24 for ventilation.
  • the optimum film thickness of the vibrating membrane 24 is 0.5 to 2 ⁇ m.
  • the reason is as follows. That is, if the film thickness of the vibration film 24 is too thin, the resonance frequency tends to be too small, and resonance of the vibration film 24 may appear in the audible range. On the other hand, if the film thickness of the vibration film 24 is too thick, the vibration film 24 becomes hard and the microphone sensitivity tends to decrease.
  • As the configuration of the vibration film 24, a structure in which a resin film and a metal film are stacked on the silicon substrate 22 may be employed.
  • a surface protective layer 34 made of a photoresist is laminated on the upper surface of the insulating layer 30. At this time, the surface protective layer 34 is formed so as to cover the outer peripheral edge portion of the vibration film 24 and the pair of terminal portions 32A and 32B. A pair of holes 34a and 34b for exposing the pair of terminal portions 32A and 32B are formed at two locations on the outer peripheral edge of the surface protective layer 34.
  • a resist layer extending in a cylindrical shape in the vertical direction is formed on the upper surface of the surface protective layer 34 so as to surround the sound hole 60a, thereby constituting the sound path wall 70.
  • the resist layer constituting the sound road wall 70 is formed of an organic compound called a permanent photoresist.
  • a permanent photoresist for example, TMMR series S2000 manufactured by Tokyo Ohka Kogyo Co., Ltd., SU-8 series 3000 manufactured by Nippon Kayaku Co., Ltd., etc. can be used. These permanent photoresists can be increased in film thickness, can be adjusted to various film thicknesses, and have appropriate elasticity.
  • the resist layer constituting the sound path wall 70 is disposed in a state where its upper end surface is brought into contact with the lower surface of the upper surface wall 60A of the cover 60 and is compressed and elastically deformed in the vertical direction.
  • the resist layer constituting the sound path wall 70 is in an unloaded state as shown by a two-dot chain line in FIG. 2 and the upper surface wall 60A of the cover 60 and the upper surface of the microphone element 20 (that is, the upper surface of the surface protective layer 34). ) To be slightly higher than the interval. For example, if the interval is about 0.3 mm, the distance is 10% higher than that of about 0.33 mm.
  • the resist layer constituting the sound path wall 70 is pressed downward by contact with the upper surface wall 60A in a state where the cover 60 is placed and fixed on the base substrate 50, and is somewhat compressed elastically in the vertical direction. Deformed state.
  • the lower end portion of the silicon substrate 22 is cut off in the radial direction at four locations, thereby forming four concave groove portions 22b. These four concave groove portions 22b are formed at four locations in a cross arrangement in a plan view. At this time, each of the concave groove portions 22b is formed by cutting a part of the lower end portion of the silicon substrate 22 linearly with a trapezoidal cross-sectional shape from the lower end surface.
  • the four concave grooves 22b and the upper surface of the base substrate 50 are formed with four communication holes 80 for communicating the central opening 22a and the outer peripheral space C3.
  • the rear space C2 located below the capacitor structure C is divided into a volume corresponding to the central opening 22a and a volume of the outer peripheral space C3 and a volume of the four communication holes 80. Is expanded to the combined volume.
  • 4 to 6 are side sectional views showing the manufacturing process of the microphone element 20.
  • an SOI Silicon
  • a silicon oxide film 128 and a thin silicon layer 126 as a device layer are laminated in this order on the upper surface of a thick silicon layer 122 as a handle layer.
  • On Insulator wafer 100 is prepared.
  • the SOI wafer 100 is shown in a size corresponding to the size of one microphone element 20 (the two-dot chain line in the drawing shows a part of the entire shape).
  • the SOI wafer 100 is thermally oxidized to form thin silicon oxide films 136 and 102 on both upper and lower surfaces thereof.
  • the concave grooves 122b are formed at the lower end of the silicon layer 122 of the SOI wafer 100 in a lattice arrangement in plan view.
  • the silicon oxide film 136 on the lower surface is etched, and anisotropic wet etching is performed using the etched silicon oxide film 136 as a mask to form a plurality of concave grooves 122 b in the silicon layer 122.
  • These concave groove portions 122b are to be the concave groove portions 22b of the microphone element 20.
  • fine holes 126a are formed in the silicon layer 126 of the SOI wafer 100 by etching. These holes 126 a are to be the through holes 26 a of the fixed electrode 26 in the microphone element 20.
  • the hole 126 a of the silicon layer 126 is refilled with the silicon oxide film 104 and the polycrystalline silicon thin film 106.
  • the silicon oxide film 104 and the polycrystalline silicon thin film 106 can be formed by a CVD (Chemical Vapor Deposition) method or the like.
  • the silicon oxide film 130 is formed on the surface of the silicon layer 126 as shown in FIG.
  • the silicon oxide film 130 includes the silicon oxide film 104 in a part thereof.
  • the silicon oxide film 130 is to be the insulating layer 30 that determines the gap between the fixed electrode 26 and the vibration film 24.
  • the silicon oxide film 130 is partially etched to form a small hole 130a, and is patterned so as to be electrically connected to the silicon layer 126 of the SOI wafer 100.
  • a polycrystalline silicon thin film 124 is formed on the upper surface of the silicon oxide film 130 as shown in FIG. At that time, patterning is performed by partial etching so that fine holes 124a are formed.
  • This polycrystalline silicon thin film 124 should be the vibration film 24.
  • the metal thin films 132A and 132B are formed and patterned at two locations on the upper surface of the silicon oxide film 130.
  • These metal thin films 132A and 132B should be the terminal portions 32A and 32B, respectively.
  • a passivation film 134 is formed on the upper surface of the silicon oxide film 130 by spin coating with a photoresist and patterning. This passivation film 134 should be the surface protective film 34.
  • parylene, silicon oxide, or the like is preferably used in addition to the photoresist.
  • small holes 134a and 134b are formed at two locations on the passivation film 134 in order to establish electrical connection with the metal thin films 132A and 132B.
  • a permanent photoresist for example, TMMR series S2000 manufactured by Tokyo Ohka Kogyo Co., Ltd.
  • This resist layer 170 is to be the sound path wall 70.
  • the height of the resist layer 170 is adjusted by the spin coating rotation speed and the rotation time.
  • the silicon layer 122 is etched by DRIE (that is, deep reactive etching) from the lower surface of the SOI wafer 100, and the DRIE is terminated at the silicon oxide film 104 that becomes the BOX layer. . Thereby, a cylindrical central opening 122a is formed.
  • the central opening 122a should be the central opening 22a.
  • the silicon oxide film 128 and the polycrystalline silicon thin film 106 and the silicon oxide film 130 refilled in the silicon layer 126 are dry-etched with hydrogen fluoride gas and xenon fluoride gas.
  • the polycrystalline silicon thin film 124 is released as the vibration film 24 (that is, the vibration film 24 is allowed to vibrate) as shown in FIG.
  • the microphone element 20 is separated into chips from the SOI wafer 100 by dicing.
  • the condenser microphone 10 has a configuration in which a microphone element 20 in which a capacitor structure C is laminated on a silicon substrate 22 is placed and fixed on a base substrate 50 together with an IC chip 40, and
  • the cover 60 fixed to the base substrate 50 so as to cover the microphone element 20 and the IC chip 40 is for guiding sound to the capacitor structure C at a position above the capacitor structure C on the upper surface wall 60A.
  • the sound hole 60a is formed between the upper wall 60A of the cover 60 and the microphone element 20, and surrounds the front space C1 between the capacitor structure C and the sound hole 60a and the front space C1. Since the sound path wall 70 that separates from the outer peripheral space C3 is disposed, the following effects can be obtained. Can.
  • the resonance frequency of the front space C1 can be set to a value of 50 kHz or higher that is sufficiently higher than the audible range (generally 20 Hz to 20 kHz).
  • the sound connection wall 70 does not need an electrical connection function with respect to the capacitor structure C, and the function can be specialized in a partitioning function between the front space C1 and the outer peripheral space C3.
  • the degree of freedom of the volume and shape of the microphone can be increased, which makes it easy to ensure the uniformity of the microphone sensitivity in the audible range.
  • the condenser microphone 10 having the microphone element 20 manufactured by using the MEMS technology even if the microphone element 20 is mounted and fixed on the base substrate 50, the microphone sensitivity can be improved. Uniformity can be ensured.
  • the sound path wall 70 is composed of a resist layer formed on the upper surface of the microphone element 20, the sound path wall is formed in the step of forming the microphone element 20 using the MEMS technology. 70 can be laminated at the same time, whereby the sound path wall 70 can be easily and accurately positioned. Moreover, the resist layer laminated as the sound path wall 70 is disposed in a state where the upper end surface thereof abuts on the upper surface wall 60A of the cover 60 and is compressed and elastically deformed in the vertical direction. Despite being composed only of the resist layer, the front space C1 and the outer peripheral space C3 can be reliably partitioned.
  • the partition function is achieved by the compression elastic deformation action of the resist layer laminated as the sound path wall 70. Can be maintained.
  • the concave groove portions 22b are formed at the lower end portion of the silicon substrate 22, and the central opening portion 22a and the outer peripheral space C3 are communicated with each other by the concave groove portions 22b and the upper surface of the base substrate 50. Since the four communication holes 80 to be formed are formed, the rear space C2 located below the capacitor structure C is divided into a volume corresponding to the central opening 22a, a volume of the outer peripheral space C3, and four locations of the rear space C2. The volume of the communication hole 80 and the volume of the communication hole 80 can be expanded to ensure the required acoustic characteristics.
  • the front space C1 and the outer peripheral space C3 are partitioned by the sound path wall 70, so that even if the communication hole 80 is formed, the front space C1 and the rear space C2 Will not communicate with each other through the outer peripheral space C3, so that there is no possibility of disturbing the microphone function.
  • the communication hole 80 is formed by cutting off a part of the lower end portion of the silicon substrate 22, the communication hole 80 can be formed at the same time in the process of forming the microphone element 20 in a stacked manner.
  • FIG. 7 is a view similar to FIG. 1, showing a condenser microphone 210 according to this modification.
  • the condenser microphone 210 As shown in the figure, the condenser microphone 210 according to this modification is the same in the basic configuration as in the above embodiment, but the configuration of the sound path wall 270 is different from that in the above embodiment. Yes.
  • the sound path wall 70 of the above embodiment is configured only by the resist layer laminated on the upper surface of the microphone element 20, but the sound path wall 270 of the present modification is laminated on the upper surface of the microphone element 20.
  • the resist layer 272 is formed, and an annular elastic member 274 interposed between the upper end surface of the resist layer 272 and the upper wall 60A of the cover 60.
  • the height of the resist layer 272 of the present modification is set to a value smaller than the distance between the upper surface of the microphone element 20 and the lower surface of the upper surface wall 60A of the cover 60.
  • the elastic member 274 is composed of a member having a lower elastic modulus than the resist layer 272. At this time, the width of the elastic member 274 is formed to be somewhat wider than the width of the resist layer 272, and the thickness is the distance between the upper end surface of the resist layer 272 and the lower surface of the upper surface wall 60A of the cover 60. A slightly larger value is set. In the sound path wall 270, the elastic member 274 is mainly elastically deformed in the vertical direction.
  • the front space C1 and the outer peripheral space C3 can be reliably partitioned.
  • FIG. 8 is a view similar to FIG. 1, showing a condenser microphone 310 according to this modification.
  • the condenser microphone 310 has the same basic configuration as that of the first modification, but the configuration of the sound path wall 370 and the cover 360 is the same as that of the first modification. This is different from the case of the first modification.
  • the cover 360 of this modification has a configuration in which an annular flange portion 360b protruding downward along the outer peripheral shape of the sound hole 360a is formed on the upper surface wall 360A.
  • the sound path wall 370 of the present modified example is similar to the sound path wall 270 of the first modified example, in that the resist layer 372 is formed on the upper surface of the microphone element 20, the upper end surface of the resist layer 372, and the cover 360.
  • the elastic member 374 is interposed between the upper surface wall 360A and the lower surface of the upper wall 360A.
  • the resist layer 372 and the elastic member 374 are more than the resist layer 272 and the elastic member 274 of the first modification. It is formed with a slightly larger diameter. As a result, the elastic member 374 comes into surface contact with the outer peripheral surface of the annular flange portion 360b of the cover 360 on the inner peripheral surface thereof.
  • the partition function between the front space C1 and the outer peripheral space C3 can be further enhanced. Further, by engaging the annular flange portion 360b of the cover 360 with the elastic member 374 of the sound path wall 270, the elastic member 374 can be temporarily fixed at a predetermined position, whereby the work for assembling the condenser microphone 10 can be performed. Can increase the sex.
  • FIG. 9 is a view similar to FIG. 1, showing a condenser microphone 410 according to this modification.
  • the condenser microphone 410 has the same basic configuration as that of the above embodiment, but the configurations of the silicon substrate 422 and the base substrate 450 of the microphone element 420 are the same. This is different from the above embodiment.
  • the concave groove corresponding to the concave groove 22b in the silicon substrate 22 of the above embodiment is not formed.
  • the upper surface of the base substrate 450 of the present modification is cut into concave grooves at four locations. Then, through the recessed grooves 450a formed at these four locations and the lower end surface of the silicon substrate 422, four communication holes 480 are provided for communicating the central opening 22a and the outer peripheral space C3.
  • the volume of the rear space C2 can be made sufficiently large, thereby ensuring the required acoustic characteristics.
  • the configuration of the base substrate 450 can be simplified by adopting the configuration of this modified example, the layer forming process of the microphone element 420 can also be simplified.
  • the formation of the four recessed groove portions 450a can be performed by, for example, partially cutting a plurality of conductive layers laminated on the insulating substrate of the base substrate 50.

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  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Acoustics & Sound (AREA)
  • Signal Processing (AREA)
  • Manufacturing & Machinery (AREA)
  • Electrostatic, Electromagnetic, Magneto- Strictive, And Variable-Resistance Transducers (AREA)
  • Details Of Audible-Bandwidth Transducers (AREA)

Abstract

L'invention porte sur un microphone à condensateur comprenant un élément de microphone fabriqué à l'aide de la technique des systèmes micro-électromécaniques (MEMS), permettant de garantir une uniformité de la sensibilité du microphone même si l'élément de microphone est configuré pour être monté et fixé sur un substrat de base. On monte et on fixe sur un substrat de base (50) un élément de microphone (20) formé par mise en place d'une partie de structure de condensateur (C) sur un substrat de silicium (22), conjointement avec une puce à circuit intégré (CI) (40). On forme alors une rosace (60a) destinée à guider le son vers la partie de structure de condensateur (C) dans une position au-dessus de la partie de structure de condensateur (C), dans une paroi de la surface supérieure (60A) d'un couvercle (60) fixé au substrat de base (50) de façon à recouvrir l'élément de microphone et la puce CI. Une paroi de trajet sonore (70) servant de séparation entre un espace antérieur (C1) situé entre la partie de structure de condensateur (C) et la rosace (60a) et un espace périphérique extérieur (C3) entourant l'espace antérieur est disposée entre la paroi de surface supérieure (60A) du couvercle (60) et l'élément de microphone (20), permettant ainsi de réduire la capacité de l'espace antérieur (C1).
PCT/JP2010/005012 2009-08-26 2010-08-10 Microphone à condensateur WO2011024397A1 (fr)

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JP2009195477A JP2011049752A (ja) 2009-08-26 2009-08-26 コンデンサマイクロホン
JP2009-195477 2009-08-26

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Cited By (3)

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GB2506979A (en) * 2012-09-24 2014-04-16 Wolfson Microelectronics Plc MEMS device with increased robustness and resilience to acoustic shock
JP2017519419A (ja) * 2014-05-14 2017-07-13 エプコス アクチエンゲゼルシャフトＥｐｃｏｓ Ａｇ マイクロフォン
EP3806486A4 (fr) * 2018-05-30 2021-11-17 Sony Group Corporation Dispositif de traitement d'informations

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US20140064546A1 (en) * 2012-08-01 2014-03-06 Knowles Electronics, Llc Microphone assembly
KR101641220B1 (ko) * 2015-03-31 2016-07-21 주식회사 루셈 인쇄회로기판 내에 배치된 커패시터를 구비한 ｍｅｍｓ 마이크로폰
CN108900942B (zh) * 2018-07-16 2019-12-17 维沃移动通信有限公司 一种播放控制方法及电子设备
US10863282B2 (en) 2019-01-30 2020-12-08 Sae Magnetics (H.K.) Ltd. MEMS package, MEMS microphone and method of manufacturing the MEMS package
US10934159B2 (en) 2019-06-03 2021-03-02 Sae Magnetics (H.K.) Ltd. MEMS package, MEMS microphone, method of manufacturing the MEMS package and method of manufacturing the MEMS microphone

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