JP2003163998A - Capacitor microphone, method for manufacturing the same, and electronic equipment - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for manufacturing a capacitor microphone whose sensitivity can be improved, the capacitor microphone, and electronic equipment having the capacitor microphone. <P>SOLUTION: The capacitor microphone 1 is constituted by connecting a back plate board 2 to a diaphragm board 4 with resin. The back plate board 2 is provided with a first board 21, and the first board 21 is formed with an electrode 251 and a plurality of acoustic holes 31. A back plate 20 is constituted of the part formed with the electrode 251 and the acoustic holes 31. The diaphragm board 4 is provided with a second board 41, and the second board 41 is formed with a diaphragm 40 having an electrode 451 movable to the back plate 20. A hollow part (void) 6 is formed between the back plate 20 and the diaphragm 40, and a prescribed region other than the hollow part 6 is formed with a non-contact part 7 where the back plate board 2 and the diaphragm board 4 are brought into non-contact with each other. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a condenser microphone, a condenser microphone, and electronic equipment.

[0002]

2. Description of the Related Art A condenser microphone is known in which a back plate having a plurality of through holes called acoustic holes formed on a silicon substrate and a diaphragm movable with respect to the back plate are provided so as to form a capacitor. ing. The condenser microphone is advantageous for miniaturization and low power consumption, and can integrate a circuit to reduce noise.

As a method of manufacturing this condenser microphone, for example, "A Silicon Condenser microphone w
ith Structured Back Plate and Silicon Nitride Memb
rane "Sensors and Actuators, 1992, 251st-2nd
On page 58, Wolfgang Kuhnel et al. Disclose a method of manufacturing a diaphragm chip and a backplate chip using a silicon substrate, and then joining the diaphragm chip and the backplate chip.

In the method of manufacturing the condenser microphone described above, in the manufacturing process of the back plate chip, the acoustic hole provided in the back plate for suppressing the influence of air damping is formed by wet etching using an alkaline aqueous solution as an etching solution.

Further, in the manufacturing process of the diaphragm chip, the silicon substrate is partially removed to form a diaphragm having a quadrangular shape in plan view.

However, in the method of manufacturing the condenser microphone described above, an insulating film serving as a spacer for forming a gap between electrodes is formed outside the diaphragm, and the insulating film is a dielectric (insulator). Therefore, the silicon substrate on the back plate chip side and the silicon substrate on the diaphragm chip side become electrodes, and both electrodes,
Due to the insulating film between them, a capacitance is generated in a portion outside the diaphragm (a pseudo capacitor is formed),
It becomes a parasitic capacitance.

Due to this parasitic capacitance, the capacitance of the movable portion, that is, the capacitance of the diaphragm is smaller than the capacitance of the entire condenser microphone, and the sensitivity of the condenser microphone is reduced (change in capacitance due to vibration of the diaphragm). Is difficult to detect with high accuracy).

[0008]

SUMMARY OF THE INVENTION An object of the present invention is to provide a method of manufacturing a condenser microphone, which can improve the sensitivity, a condenser microphone, and an electronic device having the condenser microphone.

[0009]

These objects are achieved by the present invention described in (1) to (38) below.

(1) Forming an electrode on a first semiconductor substrate and forming at least one through hole to manufacture a back plate substrate having a back plate on which the through hole and the electrode are provided. Process and the second
A second step of manufacturing a diaphragm substrate by forming a movable diaphragm having electrodes on the semiconductor substrate, and the back plate and the diaphragm face each other through a gap to form a capacitor, and A third step of joining the back plate substrate and the diaphragm substrate so that a non-contact portion where the back plate substrate and the diaphragm substrate are not in contact with each other is formed in the region. Method of manufacturing condenser microphone.

(2) A portion of the first semiconductor substrate corresponding to the back plate is partially removed to form a thin portion,
A first step of forming an electrode and forming at least one through hole in the thin portion to manufacture a back plate substrate having a back plate provided with the through hole and the electrode; and a second semiconductor A second step of manufacturing a diaphragm substrate by forming a movable diaphragm having an electrode on a substrate, and the back plate and the diaphragm face each other with a gap therebetween to form a capacitor, and a region other than the gap. A third step of joining the back plate substrate and the diaphragm substrate so that a non-contact portion where the back plate substrate and the diaphragm substrate are not in contact with each other is formed. Microphone manufacturing method.

(3) Forming an electrode on a first semiconductor substrate and forming at least one through hole to manufacture a back plate substrate having a back plate on which the through hole and the electrode are provided. Process and the second
Forming a film forming at least a part of the diaphragm on the semiconductor substrate, partially removing a portion corresponding to the diaphragm of the second semiconductor substrate, and forming an electrode on the removed portion of the film, A second step of manufacturing a diaphragm substrate having a movable diaphragm including the film and the electrode, and the back plate and the diaphragm face each other through a gap to form a capacitor, and in a region other than the gap, A condenser microphone, comprising: a third step of joining the back plate substrate and the diaphragm substrate so that a non-contact portion where the back plate substrate and the diaphragm substrate are not in contact with each other is formed. Manufacturing method.

(4) A portion corresponding to the back plate of the first semiconductor substrate is partially removed to form a thin portion,
A first step of forming an electrode and forming at least one through hole in the thin portion to manufacture a back plate substrate having a back plate provided with the through hole and the electrode; and a second semiconductor A film forming at least a part of a diaphragm is formed on a substrate, a portion of the second semiconductor substrate corresponding to the diaphragm is partially removed, and an electrode is formed on the removed portion of the film to form the film. And a second step of manufacturing a diaphragm substrate having a movable diaphragm provided with the electrode, and the back plate and the diaphragm face each other through a gap to form a capacitor, and in a region other than the gap,
A condenser microphone, comprising: a third step of joining the back plate substrate and the diaphragm substrate so that a non-contact portion where the back plate substrate and the diaphragm substrate are not in contact with each other is formed. Manufacturing method.

(5) In the first step, the non-contact portion is formed by forming a film serving as a spacer for forming the void in a predetermined pattern on the first semiconductor substrate. ) To (4), the method for manufacturing the condenser microphone according to any one of (4) to (4).

(6) In the first step, the concave portion forming at least a part of the non-contact portion is formed on the side of the first semiconductor substrate which is to be joined to the diaphragm substrate. A method of manufacturing a condenser microphone according to any one of (1) to (5).

(7) The method for manufacturing a condenser microphone according to the above (6), wherein the recess is formed by an etching method in the first step.

(8) In the first step, the through hole is formed by a dry etching method (1)
A method for manufacturing a condenser microphone according to any one of (1) to (7).

(9) The method of manufacturing a condenser microphone according to (8), wherein the dry etching method is a method of alternately repeating etching with an etching gas and forming a protective film with a deposition gas. .

(10) In the first step, the electrodes are formed by doping the first semiconductor substrate with a dopant that improves the conductivity of the first semiconductor substrate. A method for manufacturing a condenser microphone according to any one of 1.

(11) The method for manufacturing a condenser microphone according to the above (10), wherein the dopant is boron.

(12) In the second step, a concave portion which forms at least a part of the non-contact portion is formed on the surface of the second semiconductor substrate which is joined to the back plate substrate. The manufacturing method of the condenser microphone according to any one of (1) to (11).

(13) The method of manufacturing a condenser microphone according to the above (12), wherein the recess is formed by an etching method in the second step.

(14) The method for manufacturing a condenser microphone according to any one of the above (1) to (13), wherein in the second step, at least a part of the diaphragm is formed of a nitride film.

(15) In the second step, holes (1) to (1) are formed in the second semiconductor substrate for connecting to electrodes of the back plate substrate.
4. The method for manufacturing a condenser microphone according to any one of 4).

(16) In the second step, holes are formed in the second semiconductor substrate at positions corresponding to the pads connected to the electrodes of the back plate substrate. The manufacturing method of the condenser microphone according to any one of 1) to 3) above.

(17) In the second step, the removal of the second semiconductor substrate for forming the diaphragm is performed by an etching method, and at that time, the hole is formed (15) or (16). ) The method of manufacturing a condenser microphone described in (1).

(18) The thickness of the diaphragm is smaller than the thickness of the back plate (1) to (1).
7. The method for manufacturing a condenser microphone according to any one of 7).

(19) The method of manufacturing a condenser microphone according to any one of (1) to (18), wherein the first semiconductor substrate is a single crystal silicon substrate.

(20) The first semiconductor substrate is (1
The above (1) which is a (00) plane orientation or a (110) plane orientation
9) A method for manufacturing a condenser microphone according to 9).

(21) The method for manufacturing a condenser microphone according to any one of the above (1) to (20), wherein the second semiconductor substrate is a single crystal silicon substrate.

(22) The second semiconductor substrate is (1
The above (2) which is a (00) plane orientation or a (110) plane orientation.
The method for manufacturing a condenser microphone according to 1).

(23) A condenser microphone manufactured by the method for manufacturing a condenser microphone according to any one of the above (1) to (22).

(24) An electrode is formed on the first semiconductor substrate,
A back plate substrate provided with a back plate having at least one through hole, and a second semiconductor substrate,
A diaphragm substrate provided with a movable diaphragm having electrodes, and the back plate substrate and the diaphragm substrate are joined so that the back plate and the diaphragm face each other with a gap therebetween to form a capacitor. A condenser microphone having a non-contact portion in which the back plate substrate and the diaphragm substrate are in non-contact with each other in a region other than the gap.

(25) A spacer for forming the gap is provided between the first semiconductor substrate and the second semiconductor substrate, and at least a part of the non-contact portion does not have the spacer. The condenser microphone according to (24) above, which is composed of parts.

(26) The diaphragm substrate has a film forming at least a part of the diaphragm, and at least a part of the non-contact part is formed by the part without the film. 25) The condenser microphone described in 25).

(27) At least a part of the non-contact portion is formed by a recess provided in the first semiconductor substrate and / or the second semiconductor substrate.
The condenser microphone according to any one of 4) to (26).

(28) In the plan view, the area ratio of the non-contact portion with respect to the condenser microphone excluding the void is 70 to 90%, according to any one of the above (24) to (27). Condenser microphone.

(29) The electrode of the back plate substrate is formed by doping the first semiconductor substrate with a dopant that improves the conductivity of the first semiconductor substrate. The condenser microphone according to any one of (28).

(30) The condenser microphone according to the above (29), wherein the dopant is boron.

(31) At least a part of the diaphragm is made of a nitride film.
A condenser microphone according to any one of (1) to (30).

(32) The condenser microphone according to any one of (24) to (31), wherein the diaphragm substrate has a hole for connecting to an electrode of the back plate substrate.

(33) The condenser microphone according to any one of (24) to (32), wherein the diaphragm has a thickness smaller than that of the back plate.

(34) The condenser microphone according to any one of (24) to (33), wherein the first semiconductor substrate is a single crystal silicon substrate.

(35) The first semiconductor substrate is (1
The above (3) which is a (00) plane orientation or a (110) plane orientation.
The condenser microphone described in 4).

(36) The condenser microphone according to any one of (24) to (35), wherein the second semiconductor substrate is a single crystal silicon substrate.

(37) The second semiconductor substrate is (1
The above (3) which is a (00) plane orientation or a (110) plane orientation.
The condenser microphone according to 6).

(38) An electronic device having the condenser microphone according to any one of (23) to (37).

[0048]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, a method for manufacturing a condenser microphone, a condenser microphone, and an electronic device according to the present invention will be described in detail with reference to the preferred embodiments shown in the accompanying drawings.

FIG. 1 is a sectional perspective view showing an embodiment of a condenser microphone of the present invention, FIG. 2 is a vertical sectional view showing an embodiment of a condenser microphone of the present invention, and FIG.
FIG. 3 is a plan view of a back plate substrate of the condenser microphone shown in FIGS. 1 and 2.

A condenser microphone (condenser-type microphone) 1 shown in these figures is one in which a back plate substrate (back plate chip) 2 and a diaphragm substrate (diaphragm chip) 4 are joined (bonded together).

A large number (a plurality) of back plate substrates 2 are formed on a wafer, and each back plate substrate 2 is divided (separated), and similarly, a large number of diaphragm substrates 4 are formed on a wafer, for example. (Plurality) are formed, divided (separated) for each diaphragm substrate 4, and thereafter,
The back plate substrate 2 and the diaphragm substrate 4 are joined to complete the condenser microphone 1.

The back plate substrate 2 has a first substrate 21 which is a semiconductor substrate, and an electrode 251 and a plurality of acoustic holes (through holes) 31 are provided on the first substrate 21. The portion where the electrode 251 and the acoustic hole 31 are provided constitutes the back plate 20. A recess 23 is formed in a portion of the first substrate 21 corresponding to the back plate 20.

The diaphragm substrate 4 has a second substrate 41 which is a semiconductor substrate. The back plate 20 (back plate substrate 2) is provided on the second substrate 41.
A diaphragm 40 having a movable (displaceable) electrode 451 with respect to is provided. The second substrate 41
A hole 43 is formed in a portion corresponding to the diaphragm 40.

The back plate substrate 2 and the diaphragm substrate 4 are the back plate 20 and the diaphragm 40.
Are arranged so as to form a capacitor, and a hollow portion (void) 6 is formed between the back plate 20 and the diaphragm 40.

Then, in a predetermined area other than the hollow portion 6,
A non-contact portion 7 is formed in which the back plate substrate 2 and the diaphragm substrate 4 are in non-contact with each other. The non-contact portion 7 will be described in detail later.

The size of the condenser microphone 1 is not particularly limited, but may be, for example, about 2 to 5 mm × 2 to 5 mm, and the thickness may be about 0.2 to 1 mm.

Next, a method of manufacturing the condenser microphone 1 will be described. 4 to 27 are views (longitudinal cross-sectional views) for explaining the method of manufacturing the condenser microphone 1, respectively, and FIGS. 4 to 21 are the manufacturing process of the back plate substrate 2 (first process). 22 to 26 are manufacturing steps of the diaphragm substrate 4 (second step).
FIG. 27 shows a step (third step) of joining the back plate substrate 2 and the diaphragm substrate 4 together.

First, the first substrate 21 and the second substrate 4
As 1, the semiconductor substrate is prepared.

These first substrate 21 and second substrate 4
Each of 1 is not particularly limited as long as it is a semiconductor substrate, but is preferably a single crystal silicon substrate, and the single crystal silicon substrate has a (100) plane orientation (crystal plane orientation) or a (110) plane orientation. (Crystal plane orientation) is more preferable.

As a result, the diaphragm 40 and the back plate 20 can be accurately formed, and the condenser microphone 1 as designed can be obtained.

Further, the first substrate 21 and the second substrate 4
The thickness of 1 is not particularly limited, but is 300 to
It is preferably about 525 μm, and 300 to 400 μm.
It is more preferably about m.

<Manufacturing Process of Back Plate Substrate 2 (First
Process)><1> First, as shown in FIG. 4, a mask for etching is formed on the surface of the first substrate 21, that is, on the upper side, the lower side, the right side, and the left side of the first substrate 21 in FIG. A film 22 that becomes is formed.

The constituent material of the film 22 is, for example, Si.
₃ N _{4 and the} like. The film 22 is formed, for example, by CVD (Ch
It is formed by an emical vapor deposition (especially thermal CVD) method or the like.

Although the thickness of the film 22 is not particularly limited,
It is preferably about 0.05 to 0.2 μm, and 0.1
More preferably, it is about 0.15 μm.

<2> Next, as shown in FIG. 5, among the films 22 on the lower side of the first substrate 21 in FIG.
The portion corresponding to 0, that is, the portion corresponding to the recess 23 shown in FIG. 6 is removed, and the back plate 20 (recess 23) is removed.
An opening 221 having a shape corresponding to is formed. This allows
The first substrate 21 is exposed through the opening 221.

The film 22 can be removed by, for example, a dry etching method or a wet etching method.

<3> Next, as shown in FIG. 6, a recess 23 is formed in the opening 221 of the first substrate 21. That is, the portion of the opening 221 of the first substrate 21 is removed to a predetermined thickness to form the thin portion 211. The thin portion 211 and the portion in the vicinity thereof undergo the subsequent steps,
It becomes the back plate 20.

The thickness of the thin portion 211 of the first substrate 21, that is, the thickness of the back plate 20 is not particularly limited, but is preferably about 10 to 40 μm,
More preferably, it is about 10 to 15 μm.

The thin portion 211 (recess 23) is formed by
It is preferable to carry out by an etching method. That is, it is preferable to etch the first substrate 21 exposed from the opening 221 to form the thin portion 211.

Examples of the etching method in this case include a dry etching method and a wet etching method, and the alkali anisotropic etching method is particularly preferable.

When this step is performed by the alkali anisotropic etching method, the back plate 20 having a predetermined thickness can be accurately formed, and the condenser microphone 1 having high dimensional accuracy can be obtained.

The alkaline etching solution used in the alkaline anisotropic etching method is, for example,
An aqueous solution of TMAH (tetramethylammonium hydroxide) and the like can be mentioned.

<4> Next, as shown in FIG. 7, the film 22 is removed (peeled). For removing the film 22, for example, a phosphoric acid or hydrofluoric acid solution or the like can be used.

<5> Next, as shown in FIG. 8, a mask for etching is used on the surface of the first substrate 21, that is, on the upper side, the lower side, the right side and the left side of the first substrate 21 in FIG. A film 26 that becomes is formed.

The constituent material of the film 26 is, for example, Si.
O _{2 and the} like can be mentioned. When the film 26 is formed of a SiO ₂ film, for example, the surface (surface layer portion) of the first substrate 21 is oxidized (thermally oxidized).

The thickness of the film 26 is not particularly limited,
It is preferably about 0.05 to 1.2 μm, and 0.5
More preferably, it is about 1.2 μm.

<6> Next, as shown in FIG. 9, the portion of the film 26 on the upper side of the first substrate 21 in FIG. 9 corresponding to the concave portion 212 shown in FIG. A plurality of openings 261 having a desired shape are formed. As a result, the first substrate 21 is exposed from each opening 261.

The film 26 can be removed by, for example, a dry etching method or a wet etching method.

<7> Next, as shown in FIG. 10, the opening 261 of the first substrate 21 is removed to a predetermined depth,
A plurality of recesses 212 are formed in a predetermined area other than the hollow portion 6 on the surface of the first substrate 21 that is joined to the diaphragm substrate 4.

As shown in FIG. 2, the recess 212 and the opening 272 of the insulating film 27, which will be described later, form the non-contact portion 7.

The depth of the recess 212 of the first substrate 21 is not particularly limited, but is preferably about 10 to 210 μm, more preferably about 100 to 200 μm.

The shape of the recess 212 is not particularly limited, but in this embodiment, the shape of the recess 212 in plan view (the shape when viewed from the upper side in FIG. 10) is a quadrangle (FIG. 10). 3).

Further, the number of the concave portions 212 is appropriately set according to various conditions such as the size and shape thereof. In the present embodiment, a plurality of recesses 212 are formed (see FIG. 3), 1
Only one may be formed.

The recess 212 is preferably formed by an etching method. Examples of the etching method in this case include a dry etching method and a wet etching method, and an alkali anisotropic etching method is particularly preferable.

When this step is performed by the alkali anisotropic etching method, the concave portion 212 having a predetermined depth can be accurately formed, and the condenser microphone 1 having high dimensional accuracy can be obtained.

The alkaline etching solution used in the alkaline anisotropic etching method is, for example,
An aqueous solution of TMAH (tetramethylammonium hydroxide) and the like can be mentioned.

<8> Next, as shown in FIG.
Are removed (peeled). For removing the film 26, for example, a hydrofluoric acid solution or the like can be used.

<9> Next, as shown in FIG. 12, the surface of the first substrate 21, that is, the upper side, the lower side, the right side, and the left side in FIG. A film 24 to be the following is formed.

The constituent material of the film 24 is, for example, Si.
O _{2 and the} like can be mentioned. The film 24 is formed by, for example, a CVD method (in particular, a plasma CVD method) or the like.

Although the thickness of the film 24 is not particularly limited,
It is preferably about 0.5 to 2 μm, and 1 to 1.5 μm
It is more preferably about m.

<10> Next, as shown in FIG.
The film 24 on the upper side of FIG. 13 of the substrate 21 of FIG.
The opening 24 is formed by patterning (removing) into a shape corresponding to 3
1 is formed, and the thin portion 211 of the first substrate 21 and the portion of the thin portion 211 on the right side in FIG. 13 are exposed from the opening 241.

The electrode 251 is provided on the upper side of the thin portion 211, and the wiring 252 and the pad 253 are connected to the electrode 2
Since it is provided on the right side in FIG. 13 of 51, the opening 241 is
The thin portion 211 and the thin portion 211 are formed on the right side in FIG.

The film 24 can be removed by, for example, a dry etching method or a wet etching method.

<11> Next, as shown in FIG. 14, the surface layer on the upper side of FIG. 14 of the first substrate 21 in the opening 241, that is, the thin portion 211 and the thin portion 211 of the first substrate 21. Electrodes 251 and wirings 25 are formed by doping (injecting) boron (dopant) into the surface layer portion on the right side of FIG.
2 and the pad 253 are formed.

In this way, the electrode 25 doped with boron was used.
1. By forming the wiring 252 and the pad 253, in the step <17> described later, when the insulating film 27 is etched to form the plurality of openings 272, the etching liquid (for example, hydrofluoric acid solution) is used. It is possible to prevent the electrode 251, the wiring 252, and the pad 253 from being altered, deteriorated, peeled off, dissolved, or the like.

In the above boron doping, for example, a solid boron diffusion source (not shown) is used for the first substrate 21 shown in FIG.
The first substrate 21 is arranged on the upper middle side so as to face the first substrate 21, and heat treatment is performed.

The heat treatment condition is appropriately set according to various conditions such as the depth (thickness) of the first substrate 21 to be doped and the concentration of boron, but is about 1025 to 1200 ° C.
It is preferably about 0.5 to 12 hours, and 1075 to
It is more preferable that the temperature is about 1200 ° C. and the time is about 0.5 to 5 hours.

By this treatment, the surface layer portion of the first substrate 21 in the opening 241, that is, from the surface of the first substrate 21 to the region of the predetermined depth (thickness), has a predetermined concentration (high concentration). Boron is doped and diffused to improve conductivity (conductivity). The electrode 25 is formed by the portion (doped portion) of the first substrate 21 that is doped with boron.
1, wiring 252 and pad 253 are configured. The electrode 251 and the pad 253 are electrically connected to each other via the wiring 252.

The depth of boron doping (thickness of the doped portion), that is, the thickness of the electrode 251 is not particularly limited, but is preferably about 0.4 to 1.2 μm,
More preferably, it is about 0.5 to 1 μm.

The concentration of boron after doping is not particularly limited, but is preferably 5 × 10 ¹⁹ pieces / cm ³ or more, and more preferably 1 × 10 ²⁰ pieces / cm ³ or more. It is particularly preferable that the density is about 10 × 10 ^{20 to} 5 × 10 ²⁰ pieces / cm ³ .

The method of doping with boron is not limited to the above-mentioned method, but may be, for example, an ion implantation method or a method using a liquid diffusion source (method using boron tribromide).

The dopant is not limited to boron as long as the conductivity (conductivity) of the first substrate 21 can be improved by doping the dopant, and other than boron, for example, P, As, Al and the like are mentioned, and any two or more kinds may be used.

Further, in the present invention, the back plate substrate 2
The electrode 251, the wiring 252, and the pad 253 need only be conductive, and may be formed of, for example, various metals, polysilicon (polycrystalline silicon), or the like.

<12> Next, as shown in FIG.
4 is removed (peeled). For removing the film 24, for example, a hydrofluoric acid solution or the like can be used.

<13> Next, as shown in FIG.
16 on the upper side of the substrate 21 of FIG. 16, an insulating film 27 serving as a spacer for forming a gap (gap), that is, a hollow portion (void) 6 between the electrode 251 and a diaphragm 40 of a diaphragm substrate 4 described later is provided. Form. This insulating film 2
The thickness of 7 corresponds to the distance (gap length) between the electrode 251 of the back plate substrate 2 and the diaphragm 40 of the diaphragm substrate 4 described later.

The thickness of the insulating film 27, that is, the distance (gap length) between the electrode 251 of the back plate substrate 2 and the diaphragm 40 of the diaphragm substrate 4 described later.
Is not particularly limited, but is preferably about 1 to 5 μm, and more preferably about 1 to 3 μm.

The constituent material of the insulating film 27 is not particularly limited as long as it has an insulating property, but an oxide (oxide film) is preferable, and examples of the oxide include SiO _{2 and the} like.

When the insulating film 27 is an oxide film such as a SiO ₂ film, when the acoustic hole 31 described later is formed by dry etching, it is possible to prevent (prevent) the influence of the dry etching. it can.

The insulating film 27 is formed, for example, by the CVD method (particularly,
It is formed by a plasma CVD method or the like.

<14> Next, as shown in FIG. 17, in the insulating film 27, the electrode 251, the wiring 252, and the pad 2 are formed.
A portion corresponding to 53 is removed to form an opening 271, and the electrode 251, the wiring 252, and the pad 253 are exposed from the opening 271.

The insulating film 27 can be removed by, for example, a dry etching method, a wet etching method or the like.

<15> Next, as shown in FIG.
18 of the substrate 21 of FIG. 18 above, that is, the electrode 251 and the wiring 25 of the first substrate 21.
2 and the pad 253 on the upper side in FIG. 18 and the insulating film 27 on the upper side in FIG.
8 is formed.

This mask 28 is a mask for etching when a plurality of acoustic holes (through holes) 31 shown in FIG. 19 are formed in the back plate 20 and a plurality of openings 272 shown in FIG. 20 are formed in the insulating film 27. For example, the photolithography method is used so that the openings 281 are formed in the portions (positions) corresponding to the acoustic holes 31 and the openings 282 are formed in the portions (positions) corresponding to the openings 272, respectively. Is patterned.

The constituent material of the mask 28 is, for example,
Various resist materials can be used.

The thickness of the mask 28 is not particularly limited, but is preferably about 0.5 to 2 μm,
More preferably, it is about 1.5 μm.

The shape of the opening 281 of the mask 28 in plan view (the shape when viewed from the upper side in FIG. 18), that is, the shape of the acoustic hole 31 in plan view is not particularly limited and is, for example, circular. , Oval, polygon such as quadrangle, and the like.

The size of the opening 281 of the mask 28, that is, the size of the acoustic hole 31 is not particularly limited, but for example, when the shape in plan view is circular, the diameter is about 20 to 70 μm. Is preferred, and 30 to 6
More preferably, it is about 0 μm.

The number of the openings 281 of the mask 28, that is, the number of the acoustic holes 31 is appropriately set according to various conditions such as the size and the shape, but it is preferable that the number is 50 to 1000. / Mm ² is more preferable, and about 100 to 500 pieces / mm ² is particularly preferable. This makes it possible to more reliably reduce or prevent the influence of air damping. Needless to say, the number of acoustic holes 31 may be one.

The opening 272 of the insulating film 27 is on the side of the bonding surface of the first substrate 21 with the diaphragm substrate 4 and in a predetermined region other than the hollow portion 6, particularly in the recess 212 of the first substrate 21. It is formed at the corresponding position, and as described above,
The opening 272 (the portion without the insulating film 27) and the recess 212
And constitute the non-contact portion 7 (see FIG. 2).

The shape of the opening 282 of the mask 28 in plan view (the shape when viewed from the upper side in FIG. 18), that is, the shape of the opening 272 of the insulating film 27 in plan view is not particularly limited, but the opening 272 is not particularly limited. Is preferably formed so as to substantially coincide with the recess 212 (in substantially the same shape as the recess 212),
In the present embodiment, it has a rectangular shape (see FIG. 3).

Further, the number of openings 282 of the mask 28, that is, the number of openings 272 of the insulating film 27 is appropriately set according to various conditions such as its size and shape. In the present embodiment, the openings 282 of the mask 28, that is, the openings 272 of the insulating film 27 are formed in the same number (a plurality) as the recesses 212 (see FIG. 3), but the number of the openings 272 and the number of the recesses 212 are different. It may be different. That is, the opening 272 may be formed in a portion where the concave portion 212 is not formed.

The number of openings 272 in the insulating film 27 is
It goes without saying that the number may be one.

Further, as shown in FIG. 18, the first substrate 2
18 on the front surface (each side surface and back surface) other than the upper side in FIG.
The protective film 29 is formed.

The protective film 29 also functions as a stopper when the first substrate 21 is etched to form (penetrate) the acoustic hole 31.

As the constituent material of the protective film 29, for example,
Various resist materials can be used.

The thickness of the protective film 29 is not particularly limited, but is preferably about 1 to 5 μm, and 2 to 3 μm.
It is more preferably about m.

<16> Next, as shown in FIG. 19, a mask 2 is formed by a dry etching method, especially by Deep RIE (ICP).
The thin portion 211 of the first substrate 21 exposed through each opening 281 of No. 8 is etched to form a plurality of acoustic holes (through holes) 31.

The Deep RIE (ICP) is a method (technology) for deeply digging a semiconductor (for example, silicon), and in this step, as the Deep RIE (ICP), for example, US Pat.
The method (Bosch process) described in 501893 can be used.

That is, in this step, for example, etching with an etching gas and formation of a protective film with a deposition gas are alternately repeated to form a plurality of acoustic holes 31.

As the etching gas, for example,
SF _{6 and the} like can be mentioned, and as the deposition gas, for example, C ₄ F _{8 and the} like can be mentioned.

In this step using deep RIE (ICP), a high selection ratio can be obtained with respect to the oxide film. Therefore, for example, when the insulating film 27 is formed of SiO ₂ , it is exposed from the opening 282 of the mask 28 and the like. The insulating film 27 is not etched, only the thin portion 211 is etched from the opening 281 of the mask 28, and since it is dry etching, it is possible to perform accurate etching without being affected by the plane orientation of the first substrate 21. You can That is, only the acoustic hole 31 can be accurately and reliably formed without affecting other parts.

As described above, since the dry etching method, especially the Deep RIE (ICP) is used for forming the acoustic holes 31, a large number of acoustic holes 31 can be formed easily, reliably and accurately. Thereby, the influence of air damping can be reduced or prevented.

In the present invention, in this step, the acoustic hole 31 may be formed by using a dry etching method different from the above, or the acoustic hole 31 may be formed by a method other than the dry etching method. Good.

<17> Next, as shown in FIG. 20, the insulating film 27 exposed from each opening 282 of the mask 28 is removed by an etching method such as a dry etching method or a wet etching method, particularly a wet etching method. Etching
A plurality of openings 272 are formed in the insulating film 27. The remaining insulating film 27 becomes a spacer.

In the etching, for example, the first substrate 21 is formed of Si, and a hydrofluoric acid solution having a selective ratio with Si is used as an etching solution, so that the first substrate 21 is not etched and is insulated. Only the film 27 is etched. That is, only the opening 272 can be formed accurately and reliably without affecting other parts.

<18> A large number (plurality) of back plate substrates 2 are formed on a wafer, and the wafer is divided (separated) into each back plate substrate 2 by a predetermined means such as dicing.

Then, as shown in FIG. 21, the remaining mask 28 and protective film 29 are removed from the divided back plate substrate 2, and the back plate substrate 2 is washed.

The mask 28 and the protective film 29 can be removed by, for example, a dry etching method or a wet etching method. In this way, the back plate substrate 2 is obtained.

In the present invention, for example, grooves may be formed in a lattice pattern on the wafer in a predetermined process, and the back plate substrates 2 may be divided in the grooves. Thereby, it is possible to easily and surely divide each back plate substrate 2 without dicing, and it is possible to more reliably prevent the back plate substrate 2 from being damaged during the division.

Further, in the present invention, the back plate substrate 2
The electrode 251, the wiring 252, and the pad 253 need only be conductive, and may be formed of, for example, various metals, polysilicon (polycrystalline silicon), or the like.

<Manufacturing Process of Diaphragm Substrate 4 (Second Process)><1> First, as shown in FIG. 22, the surface of the second substrate 41, that is, the upper side of the second substrate 41 in FIG. 22, Lower,
A film 42 is formed on both the right side and the left side. This membrane 42
Serves as a mask for etching the second substrate 41 and constitutes a part of the diaphragm 40.

The constituent material of the film 42 is preferably nitride,
For example, Si ₃ N _{4 and the} like can be mentioned.

The film 42 is formed, for example, by CVD (Chemical Vap).
or Deposition) method (in particular, thermal CVD method) or the like.

The thickness of the film 42 is not particularly limited,
It is preferably about 0.05 to 0.2 μm, and 0.1
More preferably, it is about 0.15 μm.

<2> Next, as shown in FIG. 23, a portion of the upper film 42 of the second substrate 41 in FIG. 23, which corresponds to the diaphragm 40, that is, the hole 43 shown in FIG.
And a portion corresponding to the hole 44 are removed to form an opening 421 having a shape corresponding to the diaphragm 40 (hole 43) and an opening 422 having a shape corresponding to the hole 44. As a result, the second substrate 41 is exposed through the openings 421 and 422, respectively. The hole 44 is
The back plate substrate 2 is formed at a position corresponding to the pad 253.

The film 42 can be removed by, for example, a dry etching method, a wet etching method or the like.

<3> Next, as shown in FIG. 24, the opening 421 and the opening 422 of the second substrate 41 are removed until the film 42 is exposed (until the film 42 is reached), The holes 43 and 44 are formed.

The shape of these holes 43 and 44 in plan view (the shape when viewed from the upper side in FIGS. 2 and 24) is
In FIG. 24, the upper side and the lower side have a substantially similar shape (similar shape) or substantially the same shape.

The shape of the hole 43, that is, the shape of the diaphragm 40 is not particularly limited, but in the present embodiment,
In a plan view (when viewed from the upper side in FIGS. 2 and 24), it has a square shape.

The shape of the hole 44 is not particularly limited, but in the present embodiment, it has a quadrangular shape in plan view (when viewed from the upper side in FIGS. 2 and 24).

The holes 43 and 44 are preferably formed by an etching method.

Further, it is preferable that the formation of the hole 43 and the formation of the hole 44 are performed simultaneously (in the same step).

In this embodiment, the openings 421 and 422 are formed.
The second substrate 41 exposed from is etched using the film 42 as a stopper to form holes 43 and 44 at the same time (in the same step).

By simultaneously forming the holes 43 and the holes 44 (in the same step), the number of steps can be reduced, and therefore the productivity is high and the mass production is advantageous.

As the etching method, for example, a dry etching method, a wet etching method and the like can be mentioned, but the alkali anisotropic etching method is particularly preferable.

When this step is performed by the alkali anisotropic etching method, the diaphragm 40 (hole portion 43) and the hole portion 44 having predetermined dimensions can be formed with high precision,
It is possible to obtain the condenser microphone 1 having high dimensional accuracy.

The alkaline etching solution used when the alkaline anisotropic etching method is, for example,
An aqueous solution of TMAH (tetramethylammonium hydroxide) and the like can be mentioned.

<4> Next, as shown in FIG.
The film 42 on the lower side of No. 4 is removed to form an opening 423, and the hole 44 is opened (penetrated) to the lower side in FIG.

This hole 44, openings 422 and 423
Is a pad 253 of the back plate substrate 2 when the diaphragm substrate 4 and the back plate substrate 2 are joined together.
Face to face. Therefore, the diaphragm substrate 4 can be provided with wiring that is electrically connected to the pad 253 of the back plate substrate 2 through the holes 44 and the openings 422 and 423.

Thus, the diaphragm substrate 4 is formed with holes (through holes) constituted by the holes 44 and the openings 422 and 423 for connecting to the electrodes 251 (pads 253) of the back plate substrate 2. This is advantageous for downsizing the condenser microphone 1.

The film 42 can be removed by, for example, a dry etching method, a wet etching method or the like.

<5> Next, as shown in FIG. 25, a conductive film (conductor film) 45 having a predetermined conductive pattern is formed on the upper side of the second substrate 41 in FIG.

The conductive film 45 is the film 4 in the hole 43.
25, the side surface of the hole portion 43 (left side surface in FIG. 25), and the upper side of the film 42 in the vicinity of the hole portion 43 in FIG. 25, the electrode 451, the wiring 452, and the pad. 453 is formed. In this case, the electrode 451 has a hole 43.
Located on the upper side of the inner membrane 42 in FIG. 25, the pad 453 is
The electrode 451 and the pad 453 are located above the film 42 in the vicinity of the hole 43 in FIG. The electrode 451 constitutes a part of the diaphragm 40.

In this way, the hole 4 of the second substrate 41 is formed.
The diaphragm 40 including the film 42 and the electrode 451 is formed on the lower side of FIG. The shape of the diaphragm 40 in plan view (the shape when viewed from the upper side in FIGS. 2 and 25) is similar to or the same as the shape of the hole 43 in plan view.

The method of forming the conductive film 45 is not particularly limited, and examples thereof include wet plating methods such as electrolytic plating (electroplating) and electroless plating, and vapor phase methods such as sputtering, ion plating, vacuum deposition and CVD. A film forming method and the like can be mentioned.

The conductive film 45 has conductivity, and examples of the constituent material thereof include various metals, polysilicon (polycrystalline silicon), and the like. Among these, the metal is preferable.

When the conductive film 45 is formed of a metal film, the metal is not particularly limited, and examples thereof include Cu, Cu-based alloys, Al, Al-based alloys, Au, Pt, W, and W-based alloys. To be

When the conductive film 45 is formed of a polysilicon film, it is preferable to dope (inject) a predetermined dopant into the polysilicon film at a high concentration to improve the conductivity of the conductive film 45.

As the dopant, for example, B, P, A
Examples include s and Al. In addition, examples of the method of doping the dopant include ion implantation.

The thickness of the conductive film 45 (electrode 451) is not particularly limited, but the thickness of the electrode 451 is 0.05 to 1 μm.
The thickness is preferably about m, more preferably about 0.1 to 0.5 μm.

<6> A large number (plurality) of diaphragm substrates 4 are formed on a wafer, and the wafer is divided (separated) for each diaphragm substrate 4 by a predetermined means such as dicing.

Then, as shown in FIG. 26, the left and right films 42 in FIG. 25 remaining from the divided diaphragm substrate 4 are removed, and the diaphragm substrate 4 is washed.

The film 42 can be removed by, for example, a dry etching method, a wet etching method or the like. In this way, the diaphragm substrate 4 is obtained.

Here, the hole portion 43 and the diaphragm 40.
The shape of the hole 43 is not particularly limited, but the shape of the hole 43 in plan view on the lower side in FIG. 24 (the shape when viewed from above in FIG. 2 and FIG. 24), that is, the shape of the diaphragm 40 in plan view. Is preferably substantially circular.

By making the shape of the diaphragm 40 in a plan view substantially circular, it is possible to prevent (prevent) concentration of stress on the diaphragm 40, and the diaphragm 40 can be prevented.
It is possible to more reliably prevent distortion and damage of the.

Further, since the stress in the diaphragm 40 becomes uniform, the change of the sound wave (sound pressure) incident on the condenser microphone 1 can be detected by the entire diaphragm 40, and the responsiveness and sensitivity are improved.

In the present invention, if necessary, a predetermined circuit (integrated circuit) (not shown) such as an amplifier circuit and a booster circuit may be formed on the diaphragm substrate 4.

Further, in the present invention, for example, grooves may be formed in a lattice pattern on the wafer in a predetermined process, and each diaphragm substrate 4 may be divided in the grooves. Thereby, it is possible to easily and surely divide each diaphragm substrate 4 without dicing, and it is possible to more surely prevent the diaphragm substrate 4 from being damaged during the division.

To form the dividing groove, for example,
When forming the openings 421 and 422 in the film 42,
A lattice-shaped opening corresponding to the groove is formed in the film 42.
Then, the second substrate 41 is etched to form the holes 43.
When forming and 44, the portion of the lattice-shaped opening of the second substrate 41 is half-etched.

Either the first step or the second step may be performed first, or the first step and the second step may be performed in parallel (simultaneously).

<Joining Step (Third Step)><1> First, as shown in FIG. 27, the back plate substrate 2 and the diaphragm substrate 4 are aligned with each other.

In this alignment, as shown in FIG. 27, the back plate 20 and the diaphragm 40 face (match) with each other in the vertical direction (vertical direction) in FIG. 27, and the pad 253 on the back plate substrate 2 side. The relative position and posture of the diaphragm substrate 4 with respect to the back plate substrate 2 are adjusted so that the holes 44 (openings 423) on the diaphragm substrate 4 side face (coincide with). In this case, either the back plate substrate 2 or the diaphragm substrate 4 may be moved (displaced), or both may be moved (displaced).

<2> Next, an uncured or undried resin (adhesive) not shown is supplied to a predetermined portion, for example, the upper side of the insulating film 27 of the back plate substrate 2 in FIG. 27.

The resin can be supplied, for example, by applying an uncured or undried resin.

In the present invention, the resin may be supplied to the diaphragm substrate 4 side, or may be supplied to each of the back plate substrate 2 and the diaphragm substrate 4.

<3> Next, on the back plate substrate 2,
The diaphragm substrate 4 is installed via resin, and they are bonded together.

Next, the resin is cured or dried. In this way, as shown in FIGS. 1 and 2, the back plate substrate 2 and the diaphragm substrate 4 are bonded (adhered) with each other by the cured or dried resin (not shown), and the space between the back plate 20 and the diaphragm 40 is bonded. Is a hollow portion (void) 6 communicating with each acoustic hole 31 and the hole portion 44.
Is formed, and the non-contact portion 7 is formed in a predetermined area other than the hollow portion 6.

Further, as described above, the back plate 20 and the diaphragm 40 face each other (match) in the vertical direction (vertical direction) in FIGS. 1 and 2, and the pad 253 on the back plate substrate 2 side and the diaphragm. The hole portion 44 (opening 423) on the substrate 4 side faces (matches).

As described above, since the back plate substrate 2 and the diaphragm substrate 4 are joined to manufacture the condenser microphone 1, the hollow portion 6 can be formed easily, reliably and accurately.

By providing the non-contact portion 7 in the condenser microphone 1, the capacitance (parasitic capacitance) of the portion other than the diaphragm 40 in the condenser microphone 1 can be reduced.

As a result, the capacity of the diaphragm 40 is larger than the capacity of the entire condenser microphone 1, and the sensitivity of the condenser microphone 1 is improved. That is, it is possible to accurately detect the change in capacitance due to the vibration of the diaphragm 40.

Here, in plan view (when viewed from the upper side in FIG. 2), the area ratio of the non-contact portion 7 to the condenser microphone 1 excluding the hollow portion (void) is 70.
It is preferably about 90%, more preferably about 80% to 90%.

When the area ratio occupied by the non-contact portion 7 exceeds the upper limit, the insulating film 27 (spacer) becomes thin (width is small), and the strength of the condenser microphone 1 is reduced.

If the area ratio occupied by the non-contact portion 7 is less than the lower limit, the effect of reducing the capacitance (parasitic capacitance) is reduced.

Next, the pad 2 on the back plate substrate 2 side
53 and the pad 453 on the diaphragm substrate 4 side are electrically connected to a predetermined circuit (not shown), for example, by a lead wire (not shown). At this time, the connection to the pad 253 is made through the hole 44.

As described above, the condenser microphone 1 shown in FIGS. 1 and 2 is obtained.

In the present invention, the back plate substrate 2 and the diaphragm substrate 4 may be aligned after the uncured or undried resin is supplied.

Further, in the present invention, the back plate substrate 2
The diaphragm substrate 4 may be bonded to the diaphragm substrate 4 by a method other than the resin bonding method.

Next, the operation of the condenser microphone 1 will be described. When a sound, that is, a sound wave is incident on the condenser microphone 1 while the condenser microphone 1 is in an operating state, the diaphragm 40 vibrates by the sound wave (sound pressure).

When the diaphragm 40 vibrates, the diaphragm 40 (the electrode 45
The distance between 1) and the back plate 20 (electrode 251) changes, and the capacitance of the capacitor configured by the diaphragm 40 and the back plate 20 changes.

This change in capacitance is expressed as an electric signal by
Output from the condenser microphone 1. That is,
The condenser microphone 1 converts the acoustic signal into an electric signal and outputs the electric signal.

As described above, according to the condenser microphone 1 and the method of manufacturing the same, the back plate substrate 2 and the diaphragm substrate 4 are joined to manufacture the condenser microphone 1. Therefore, the back plate 20 and the diaphragm 40 are combined. The hollow portion 6 between them can be easily, reliably and accurately formed.

By providing the non-contact portion 7 in the condenser microphone 1, the capacitance (parasitic capacitance) of the portion other than the diaphragm 40 in the condenser microphone 1 is provided.
Can be reduced.

As a result, the capacity of the diaphragm 40 is larger than the capacity of the entire condenser microphone 1, and the sensitivity of the condenser microphone 1 is improved.

Further, by providing the concave portion 212 in the first substrate 21, the capacitance of the portion other than the diaphragm 40 can be further reduced, and the sensitivity of the condenser microphone 1 is further improved.

The acoustic hole 3 of the back plate 20
1 formation, dry etching method, especially Deep RIE
By using (ICP), many acoustic holes 31
Can be formed easily, reliably and accurately. Thereby, the influence of air damping can be reduced or prevented.

Therefore, the condenser microphone 1 is
It has excellent characteristics (mechanical characteristics and acoustic characteristics).

Further, the condenser microphone 1 can be formed by a semiconductor manufacturing process (in particular, micromachining). Therefore, it is possible to easily, precisely (accurately) process, has high productivity, is advantageous for mass production, and is also advantageous for downsizing.

Also, the back plate substrate 2 or diaphragm substrate 4 and the peripheral circuit of the condenser microphone 1 can be formed (integrated) on the same substrate.

Next, a second embodiment of the method of manufacturing the condenser microphone and the condenser microphone of the present invention will be described.

FIG. 28 is a vertical sectional view showing a second embodiment of the condenser microphone of the present invention.

Hereinafter, the second embodiment will be described focusing on the differences from the first embodiment described above, and the description of the same matters will be omitted.

As shown in the figure, in the condenser microphone 1 of the second embodiment, the concave portion 212 is not provided in the first substrate 21, and the opening 272 of the insulating film 27 constitutes the non-contact portion 7. There is.

Since the other structure, operation, and manufacturing method are the same as those of the first embodiment described above, the description thereof will be omitted.

According to the condenser microphone 1 of the second embodiment and the method of manufacturing the same, the same effect as that of the above-described first embodiment can be obtained.

Next, a method of manufacturing a condenser microphone and a condenser microphone according to a third embodiment of the present invention will be described.

FIG. 29 is a vertical sectional view showing a third embodiment of the condenser microphone of the present invention.

The third embodiment will be described below focusing on the differences from the second embodiment described above, and the description of the same matters will be omitted.

As shown in the figure, in the condenser microphone 1 of the third embodiment, the film 42 of the diaphragm substrate 4 is used.
An opening 424 is formed in the opening 42 of the film 42.
The non-contact part 7 is composed of 4 (the part without the film 42).

The opening 424 of the film 42 is formed, for example, by the opening 2 of the insulating film 27 in the above-described first embodiment.
It can be performed similarly to the formation of 72.

Since the other structure, operation, and manufacturing method are the same as those in the second embodiment, the description thereof will be omitted.

According to the condenser microphone 1 of the third embodiment and the method of manufacturing the same, the same effects as those of the above-described second embodiment can be obtained.

In the present invention, in the third embodiment, the opening 272 may be formed in the insulating film 27 of the back plate substrate 2 as in the second embodiment. In this case, the opening 424 of the film 42 and the opening 27 of the insulating film 27.
The non-contact portion 7 is formed by 2 and.

Further, according to the present invention, in the third embodiment, as in the first embodiment, the opening 272 is formed in the insulating film 27 of the back plate substrate 2, and the recess 212 is formed in the first substrate 21. May be formed. In this case, the opening 424 of the film 42 and the opening 272 of the insulating film 27.
And the concave portion 212 form the non-contact portion 7.

Next, a fourth embodiment of the method of manufacturing the condenser microphone and the condenser microphone of the present invention will be described.

FIG. 30 is a vertical sectional view showing a fourth embodiment of the condenser microphone of the present invention.

Hereinafter, the fourth embodiment will be described focusing on the differences from the third embodiment described above, and the description of the same matters will be omitted.

As shown in the figure, in the condenser microphone 1 of the fourth embodiment, the film 42 of the diaphragm substrate 4 is used.
An opening 424 is formed in the second substrate 41, and a recess 411 is formed on the bonding surface side of the second substrate 41 with the back plate substrate 2. The opening 424 (the portion without the film 42) of the film 42 and the recess 411 The non-contact portion 7 is constituted by and.

The opening 424 of the film 42 is formed, for example, by the opening 2 of the insulating film 27 in the first embodiment described above.
It can be performed similarly to the formation of 72.

The recess 411 of the second substrate 41 can be formed, for example, in the same manner as the recess 212 of the first substrate 21 in the above-described first embodiment.

Since the other structure, operation, and manufacturing method are the same as those of the second embodiment described above, the description thereof will be omitted.

According to the condenser microphone 1 of the fourth embodiment and the manufacturing method thereof, the same effect as that of the above-described third embodiment can be obtained.

In the fourth embodiment, by providing the concave portion 411 in the second substrate 41, it is possible to further reduce the capacity of the portion of the condenser microphone 1 other than the diaphragm 40, and the condenser microphone 1
The sensitivity of is further improved.

In the present invention, in the fourth embodiment, the opening 272 may be formed in the insulating film 27 of the back plate substrate 2 as in the second embodiment. In this case, the opening 424 of the film 42 and the opening 27 of the insulating film 27.
The non-contact portion 7 is composed of 2 and the concave portion 411.

Further, in the present invention, in the fourth embodiment, as in the first embodiment, the opening 272 is formed in the insulating film 27 of the back plate substrate 2, and the recess 212 is formed in the first substrate 21. May be formed. In this case, the opening 424 of the film 42, the recess 411, and the insulating film 27.
The opening 272 and the concave portion 212 form the non-contact portion 7.

Each condenser microphone 1 described above is
Each can be incorporated and used in various electronic devices (electronic devices).

Next, an embodiment in which the electronic device of the present invention is applied to a hearing aid will be described.

FIG. 31 is a perspective view showing an embodiment in which the electronic device of the present invention is applied to a hearing aid, that is, an embodiment of a hearing aid equipped with the condenser microphone 1 shown in FIGS.

As shown in the figure, a hearing aid (electronic device) 1
00 has a casing (exterior member) 110 in which an opening 120 is formed.

Inside the casing 110, the condenser microphone 1 shown in FIGS. 1 and 2 described above, a speaker (not shown), and a predetermined electric circuit (not shown) electrically connected to the condenser microphone 1 and the speaker are provided. , Each installed.

The condenser microphone 1 is arranged so that the second substrate 41 faces the direction of the sound source, and the hole portion 43 of the second substrate 41, that is, the diaphragm 40 is located at the position of the opening 120.

Next, the operation of the hearing aid 100 will be described. As described above, the sound (sound pressure) from the sound source is converted into an electric signal by the condenser microphone 1.

This electric signal is processed by an electric circuit, input to a speaker, converted again into sound by the speaker, and output.

As a result, the user of the hearing aid 100 can easily and surely hear the sound from the sound source.

As described above, this hearing aid 100
Has a very good performance because it incorporates the condenser microphone 1 described above.

The condenser microphone 1 of the hearing aid 100 may be replaced by any one of the condenser microphones 1 shown in FIGS. 28, 29 and 30.

Further, the present invention is not limited to the above-mentioned hearing aid, but may be, for example, a mobile phone (including PHS), a video phone, a telephone, a voice input device such as a mobile phone, a video telephone and a telephone. It can be applied to any electronic device having a microphone.

As described above, the method of manufacturing the condenser microphone, the condenser microphone and the electronic device of the present invention are
Although the description has been given based on the illustrated embodiments, the present invention is not limited to these, and the configuration of each part can be replaced with any configuration having the same function.

Further, the present invention may be a combination of any two or more configurations (features) of the above embodiments.

[0250]

As described above, according to the present invention, since the condenser microphone is manufactured by joining the back plate substrate and the diaphragm substrate, the hollow portion (void) between the electrodes can be easily, reliably and accurately formed. It can be formed well.

By providing the non-contact portion, the capacitance (parasitic capacitance) of the condenser microphone other than the diaphragm can be reduced.

As a result, the capacity of the diaphragm is larger than the capacity of the entire condenser microphone, and the sensitivity of the condenser microphone is improved.

At least a part of the non-contact part is
When the concave portion is provided on the first semiconductor substrate and / or the second semiconductor substrate, the capacitance of the portion other than the diaphragm of the condenser microphone can be further reduced, and the sensitivity of the condenser microphone can be further improved. improves.

As described above, according to the present invention, a condenser microphone having high performance, that is, having excellent mechanical and acoustic characteristics can be obtained.

Further, according to the present invention, the condenser microphone can be easily manufactured, the productivity is high, the mass production is advantageous, and the miniaturization is also advantageous.

[Brief description of drawings]

FIG. 1 is a cross-sectional perspective view showing a first embodiment of a condenser microphone of the present invention.

FIG. 2 is a vertical sectional view showing a first embodiment of a condenser microphone of the present invention.

3 is a plan view of a back plate substrate of the condenser microphone shown in FIGS. 1 and 2. FIG.

FIG. 4 is a diagram (longitudinal sectional view) for explaining a method for manufacturing the condenser microphone shown in FIGS. 1 and 2.

5 is a diagram (longitudinal sectional view) for explaining a method for manufacturing the condenser microphone shown in FIGS. 1 and 2. FIG.

FIG. 6 is a diagram (longitudinal sectional view) for explaining a method for manufacturing the condenser microphone shown in FIGS. 1 and 2.

FIG. 7 is a diagram (longitudinal sectional view) for explaining a method of manufacturing the condenser microphone shown in FIGS. 1 and 2.

FIG. 8 is a diagram (longitudinal sectional view) for explaining a method for manufacturing the condenser microphone shown in FIGS. 1 and 2.

9 is a diagram (longitudinal sectional view) for explaining a method for manufacturing the condenser microphone shown in FIGS. 1 and 2. FIG.

10 is a diagram (longitudinal sectional view) for explaining a method for manufacturing the condenser microphone shown in FIGS. 1 and 2. FIG.

FIG. 11 is a diagram (longitudinal sectional view) for explaining a method for manufacturing the condenser microphone shown in FIGS. 1 and 2.

FIG. 12 is a diagram (longitudinal sectional view) for explaining a method of manufacturing the condenser microphone shown in FIGS. 1 and 2.

FIG. 13 is a diagram (longitudinal sectional view) for explaining a method for manufacturing the condenser microphone shown in FIGS. 1 and 2.

FIG. 14 is a diagram (longitudinal sectional view) for explaining a method for manufacturing the condenser microphone shown in FIGS. 1 and 2.

FIG. 15 is a diagram (longitudinal sectional view) for explaining a method for manufacturing the condenser microphone shown in FIGS. 1 and 2.

16 is a diagram (longitudinal sectional view) for explaining a method for manufacturing the condenser microphone shown in FIGS. 1 and 2. FIG.

FIG. 17 is a diagram (longitudinal sectional view) for explaining a method for manufacturing the condenser microphone shown in FIGS. 1 and 2.

FIG. 18 is a diagram (longitudinal sectional view) for explaining a method for manufacturing the condenser microphone shown in FIGS. 1 and 2.

FIG. 19 is a diagram (longitudinal sectional view) for explaining a method for manufacturing the condenser microphone shown in FIGS. 1 and 2.

20 is a diagram (longitudinal sectional view) for explaining a method for manufacturing the condenser microphone shown in FIGS. 1 and 2. FIG.

FIG. 21 is a diagram (longitudinal sectional view) for explaining the method of manufacturing the condenser microphone shown in FIGS. 1 and 2.

22 is a diagram (longitudinal sectional view) for explaining a method for manufacturing the condenser microphone shown in FIGS. 1 and 2. FIG.

FIG. 23 is a diagram (longitudinal sectional view) for explaining a method for manufacturing the condenser microphone shown in FIGS. 1 and 2.

FIG. 24 is a diagram (longitudinal sectional view) for explaining a method for manufacturing the condenser microphone shown in FIGS. 1 and 2.

FIG. 25 is a diagram (longitudinal sectional view) for explaining a method for manufacturing the condenser microphone shown in FIGS. 1 and 2.

FIG. 26 is a diagram (longitudinal sectional view) for explaining a method for manufacturing the condenser microphone shown in FIGS. 1 and 2.

FIG. 27 is a diagram (longitudinal sectional view) for explaining a method for manufacturing the condenser microphone shown in FIGS. 1 and 2.

FIG. 28 is a vertical sectional view showing a second embodiment of the condenser microphone of the present invention.

FIG. 29 is a vertical sectional view showing a third embodiment of the condenser microphone of the present invention.

FIG. 30 is a longitudinal sectional view showing a fourth embodiment of the condenser microphone of the present invention.

FIG. 31 is a perspective view showing an embodiment when the electronic device of the invention is applied to a hearing aid.

[Explanation of symbols]

1 Condenser Microphone, 2 Back Plate Substrate, 20 Back Plate, 21 First Substrate, 211
Thin part, 212 concave part, 22 film, 221 opening, 2
3 concave part, 24 film, 241 opening, 251 electrode, 2
52 wiring, 253 pad, 26 film, 261 opening, 27 insulating film, 271, 272 opening, 28 mask, 281, 282 opening, 29 protective film, 31 acoustic hole, 32 film, 4 diaphragm substrate, 40 diaphragm, 41 second Substrate, 411 recess, 42 film, 4
21-424 opening, 43, 44 hole, 45 conductive film, 451 electrode, 452 wiring, 453 pad, 6
Hollow part, 7 non-contact part, 100 hearing aid, 110 casing, 120 opening

Claims (38)

[Claims] 1. A first plate for manufacturing a back plate substrate having an electrode formed on a first semiconductor substrate and at least one through hole formed therein, the back plate substrate having a back plate provided with the through hole and the electrode. And a second step of manufacturing a diaphragm substrate by forming a movable diaphragm having electrodes on a second semiconductor substrate, and the back plate and the diaphragm face each other with a gap therebetween to form a capacitor. And a third step of joining the back plate substrate and the diaphragm substrate so that a non-contact portion where the back plate substrate and the diaphragm substrate are in non-contact is formed in a region other than the gap. A method of manufacturing a condenser microphone, which comprises: 2. A portion of the first semiconductor substrate corresponding to the back plate is partially removed to form a thin portion, an electrode is formed, and at least one through hole is formed in the thin portion, A first step of manufacturing a back plate substrate having a back plate provided with the through holes and the electrodes, and a second step of manufacturing a diaphragm substrate by forming a movable diaphragm having electrodes on a second semiconductor substrate. And a step in which the back plate and the diaphragm face each other through a gap to form a capacitor, and a non-contact portion where the back plate substrate and the diaphragm substrate are in non-contact is formed in a region other than the gap. As described above, the capacitor plate has a third step of joining the back plate substrate and the diaphragm substrate. Method of manufacturing a Kurohon. 3. A first plate for manufacturing a back plate substrate having an electrode formed on a first semiconductor substrate and at least one through hole formed therein, the back plate substrate having a back plate provided with the through hole and the electrode. And a step of forming a film forming at least a part of the diaphragm on the second semiconductor substrate, partially removing a portion of the second semiconductor substrate corresponding to the diaphragm, and forming an electrode on the removed portion of the film. And a second step of manufacturing a diaphragm substrate having a movable diaphragm including the film and the electrode, and the back plate and the diaphragm face each other through a gap to form a capacitor and the gap. The back plate substrate and the diaphragm substrate are formed in a region other than the above region so that a non-contact portion is formed so that the back plate substrate and the diaphragm substrate do not contact each other. The third step of the manufacturing method of the condenser microphone and having a bonding the plate substrate and the diaphragm substrate. 4. A portion of the first semiconductor substrate corresponding to the back plate is partially removed to form a thin portion, an electrode is formed, and at least one through hole is formed in the thin portion, A first step of manufacturing a back plate substrate having a back plate provided with the through hole and the electrode; and forming a film forming at least a part of the diaphragm on the second semiconductor substrate, the second semiconductor A second step of partially removing a portion of the substrate corresponding to the diaphragm, forming an electrode on the removed portion of the film, and manufacturing a diaphragm substrate having a movable diaphragm including the film and the electrode; The back plate and the diaphragm face each other through a gap to form a capacitor, and the back plate substrate is provided in an area other than the gap. The way a non-contact portion and the diaphragm substrate is a non-contact is formed, the third step of the manufacturing method of the condenser microphone and having a joining of said back plate substrate and said diaphragm substrate. 5. The non-contact portion is formed by forming a film, which serves as a spacer for forming the void, in a predetermined pattern on the first semiconductor substrate in the first step. 4. The method for manufacturing the condenser microphone according to any one of 4 above. 6. The method according to claim 1, wherein in the first step, a concave portion that forms at least a part of the non-contact portion is formed on a surface of the first semiconductor substrate that is joined to the diaphragm substrate. A method for manufacturing a condenser microphone according to any one of 1. 7. The method of manufacturing a condenser microphone according to claim 6, wherein in the first step, the recess is formed by an etching method. 8. The method according to claim 1, wherein the through holes are formed by a dry etching method in the first step.
A method for manufacturing a condenser microphone according to any one of 1. 9. The method of manufacturing a condenser microphone according to claim 8, wherein the dry etching method is a method of alternately repeating etching with an etching gas and forming a protective film with a deposition gas. 10. The electrode according to claim 1, wherein in the first step, the first semiconductor substrate is doped with a dopant that improves the conductivity of the first semiconductor substrate to form an electrode. A method for manufacturing the described condenser microphone. 11. The method of manufacturing a condenser microphone according to claim 10, wherein the dopant is boron. 12. The method according to claim 1, wherein in the second step, a recessed portion that forms at least a part of the non-contact portion is formed on a side of a surface of the second semiconductor substrate which is joined to the back plate substrate. 12. The method for manufacturing a condenser microphone according to any one of 11. 13. The method of manufacturing a condenser microphone according to claim 12, wherein the recess is formed by an etching method in the second step. 14. The method of manufacturing a condenser microphone according to claim 1, wherein at least a part of the diaphragm is formed of a nitride film in the second step. 15. The condenser microphone according to claim 1, wherein in the second step, a hole for connecting to an electrode of the back plate substrate is formed in the second semiconductor substrate. Production method. 16. A hole is formed in the second step at a position corresponding to a pad connected to an electrode of the back plate substrate in the second semiconductor substrate.
15. The method for manufacturing the condenser microphone according to any one of 1 to 14. 17. The method according to claim 15, wherein in the second step, the second semiconductor substrate for forming the diaphragm is removed by an etching method, and the hole is formed at that time. Manufacturing method of condenser microphone. 18. The method of manufacturing a condenser microphone according to claim 1, wherein the diaphragm has a thickness smaller than that of the back plate. 19. The method of manufacturing a condenser microphone according to claim 1, wherein the first semiconductor substrate is a single crystal silicon substrate. 20. The first semiconductor substrate is (100)
20. The method for manufacturing a condenser microphone according to claim 19, wherein the orientation is the plane orientation or the (110) plane orientation. 21. The method of manufacturing a condenser microphone according to claim 1, wherein the second semiconductor substrate is a single crystal silicon substrate. 22. The second semiconductor substrate is (100).
22. The method of manufacturing a condenser microphone according to claim 21, wherein the orientation is the plane orientation or the (110) plane orientation. 23. A condenser microphone manufactured by the method for manufacturing a condenser microphone according to any one of claims 1 to 22. 24. A back plate substrate having a first semiconductor substrate and a back plate having electrodes and at least one through hole, and a second semiconductor substrate having a movable diaphragm having electrodes. A diaphragm substrate, wherein the back plate and the diaphragm face each other with a gap therebetween to form a capacitor, and the back plate substrate and the diaphragm substrate are joined together. A condenser microphone having a non-contact portion where the back plate substrate and the diaphragm substrate are in non-contact with each other in a region other than the void. 25. A spacer for forming the gap is provided between the first semiconductor substrate and the second semiconductor substrate, and at least a part of the non-contact portion is a portion without the spacer. 25. The condenser microphone according to claim 24, wherein the condenser microphone comprises: 26. The diaphragm substrate has a film forming at least a part of the diaphragm, and at least a part of the non-contact part is formed by a part without the film. Condenser microphone. 27. The non-contact portion according to claim 24, wherein at least a part of the non-contact portion is formed of a recess provided in the first semiconductor substrate and / or the second semiconductor substrate. Condenser microphone. 28. The condenser microphone according to claim 24, wherein an area ratio of the non-contact portion to the condenser microphone excluding the void is 70 to 90% in plan view. 29. The electrode of the back plate substrate is formed by doping the first semiconductor substrate with a dopant that improves the conductivity of the first semiconductor substrate. Condenser microphone according to any one. 30. The condenser microphone of claim 29, wherein the dopant is boron. 31. The condenser microphone according to claim 24, wherein at least a part of the diaphragm is made of a film made of a nitride. 32. The condenser microphone according to claim 24, wherein the diaphragm substrate has a hole for connecting to an electrode of the back plate substrate. 33. The condenser microphone according to claim 24, wherein a thickness of the diaphragm is thinner than a thickness of the back plate. 34. The condenser microphone according to claim 24, wherein the first semiconductor substrate is a single crystal silicon substrate. 35. The first semiconductor substrate is (100).
The condenser microphone according to claim 34, which has a plane orientation or a (110) plane orientation. 36. The condenser microphone according to claim 24, wherein the second semiconductor substrate is a single crystal silicon substrate. 37. The second semiconductor substrate is (100).
The condenser microphone according to claim 36, which has a plane orientation or a (110) plane orientation. 38. An electronic device comprising the condenser microphone according to claim 23.