JP2000013894A - Acoustic sensor, its manufacture and semiconductor electret capacitor microphone employing the acoustic sensor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a semiconductor electret capacitor microphone that can be made small. SOLUTION: The capacitor microphone is provided with the acoustic sensor and a case containing the acoustic sensor. The acoustic sensor has a semiconductor chip 110 in which a required electronic circuit is formed and a throughhole 112 is open while avoiding the electronic circuit, an electrode layer formed on the surface of the semiconductor chip 110 while avoiding the throughhole 112, an electret material 130 that is laminated on the chip 110 while avoiding part of the electrode layer and the throughhole 112, and a diaphragm film to the electret material 130 at a prescribed interval, and the electrode layer exposed from the electret material 130 connects to an electrode of the electronic circuit via the case.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an acoustic sensor, a method for manufacturing the acoustic sensor, and a semiconductor electret condenser microphone using the acoustic sensor.

[0002]

2. Description of the Related Art FIG. 8 shows a conventional electret condenser microphone. This electret condenser microphone is
And a vibrating film 7 provided inside the case 1, an electret material 5 (formed on the inner surface of the case 1) provided facing the vibrating film 7, and the vibrating film 7 and the electret. Amplifying element 9 for amplifying a change in voltage caused by a change in capacitance of a capacitor composed of material 5
And The amplifying element 9 is built in the case 1.

[0003]

However, the above-mentioned conventional electret condenser microphone is
The part constituting the amplifying element and the capacitor is completely separate, and there is a certain limit to miniaturization.

The present invention has been made in view of the above circumstances, and provides an acoustic sensor capable of significantly reducing the size of a semiconductor electret condenser microphone, a method of manufacturing the acoustic sensor, and the use of the acoustic sensor. It is an object to provide a semiconductor electret condenser microphone.

[0005]

According to the present invention, there is provided an acoustic sensor in which a required electronic circuit is formed, a semiconductor chip having a through-hole opened so as to avoid the electronic circuit, and the surface of the semiconductor chip is provided with the above-described electronic sensor. An electrode layer formed so as to avoid the through hole, an electret material laminated so as to avoid part of the electrode layer and the through hole, and a predetermined distance between the electret material and the electret material were provided. And a vibrating membrane.

Further, according to a method of manufacturing an acoustic sensor according to the present invention, a necessary electronic circuit is formed on a wafer, a through hole is formed to avoid the electronic circuit, and an electrode layer is formed on a surface of the wafer. A step of laminating an electret material avoiding a part of the electrode layer and the through-hole, a step of laminating a spacer on the electret material, and a step of laminating the electret material on the spacer. And a step of dividing the individual acoustic sensors into individual acoustic sensors.

The step of forming the through hole may be performed after the step of laminating the spacer on the electret material.

Further, a semiconductor electret condenser microphone according to the present invention includes the acoustic sensor and a case for accommodating the acoustic sensor. The electrode layer exposed from the electret material is connected to the electronic layer via the case. It is connected to the electrodes of the circuit.

[0009]

FIG. 1 is a schematic sectional view of an acoustic sensor according to an embodiment of the present invention, and FIG. 2 is a schematic sectional view showing each step of a method of manufacturing the acoustic sensor according to the embodiment of the present invention. FIGS. 3 and 3 are drawings of the acoustic sensor according to the embodiment of the present invention in the process of being manufactured. FIG. 4A is a schematic plan view, FIG. 3B is a schematic bottom view, and FIG. FIG. 5 is a schematic cross-sectional view showing each step of a method for manufacturing an acoustic sensor according to another embodiment of the present invention. FIG. 5 is a schematic explanatory view showing another method for manufacturing an acoustic sensor according to an embodiment of the present invention. 6 is a schematic sectional view of a semiconductor electret condenser microphone according to an embodiment of the present invention, and FIG. 7 is a drawing of a case body of a case used in the semiconductor electret condenser microphone according to the embodiment of the present invention. (A) from the front side Approximately perspective view and FIG (B) is a schematic perspective view from the bottom side.

[0010] An acoustic sensor 10 according to an embodiment of the present invention.
0 denotes an FET circuit 111A as a necessary electronic circuit, a response gain control circuit 111B, and an amplification circuit 111C.
And the like, and a semiconductor chip 110 in which a through hole 112 is opened to avoid the FET circuit 111A and the like.
And the FET circuit 1 formed on the semiconductor chip 110
It has an electret material 130 laminated so as to avoid the gate electrode 111a of 11A and the through-hole 112, and a vibrating film 140 provided at a predetermined interval between the electret material 130.

The configuration of the acoustic sensor 100 will be described along with its manufacturing method. Many acoustic sensors 100 are formed on one wafer 500 at the same time.
A plurality of through holes 112 are formed in the wafer 500 (see FIG. 2A). The through-hole 112 is formed in a central portion of one acoustic sensor 100 by ultrasonic processing or laser processing. The diameter of the through hole 112 is desirably 0.5 mm or less. In addition, each acoustic sensor 1
00 is set to a size of about 2 mm in width, about 2 mm in depth, and about 0.3 mm in thickness, as shown in FIG.

Next, an FET circuit 111 as an electronic circuit required by a well-known photolithography method is formed on the wafer 500 having a plurality of through holes 112 from the back side.
A, response gain control circuit 111B, amplifier circuit 1
11C and the like are formed (see FIG. 2A). This circuit 1
Of course, wiring (not shown) for connecting the circuits 11A to 111C and the circuits 111A to 111C is formed so as to avoid the through hole 112.

Further, as shown in FIG.
Power supply electrode Vcc, output electrode OUT, ground electrode GND, and gate electrode 111a, which are electrodes 11A to 111C
Are preferably formed one by one at four corners on the back side of one acoustic sensor 100.

Next, an electrode layer 120 made of aluminum is formed on the surface of the wafer 500 avoiding the through holes 112 (see FIG. 2B). The electrode layer 120 is formed of a semiconductor electret condenser microphone 60 described later.
0 through the case 200 at the gate electrode 111
It is a part connected to a. Also, this electrode layer 120
Is inserted into the through hole 112 so as not to block the through hole 112.
Formed to avoid.

An electret material 130 is laminated on the electrode layer 120 (see FIG. 2C). Therefore, the electret material 130 is electrically connected to the electrode layer 120. This electret material 130
Is formed by forming SiO ₂ having a thickness of 2 to 3 μm by plasma CVD or high-frequency magnetron sputtering, or by applying an FEP solvent by a spin-on coating method to a thickness of 10 μm.
The following thin films and the like are used.

The electret material 130 is formed avoiding the through hole 112 so as not to block the through hole 112. Further, the electret material 130 is formed so as to avoid a corner portion directly above the gate electrode 111a formed on the back surface. Therefore, the electrode layer 120
Is exposed from the electret material 130 at the corner directly above the gate electrode 111a.

A spacer 150 is formed on the electret material 130. The spacer 150 forms a predetermined space 160 between the electret material 130 and a vibration film 140 described later, and is formed of a photoresist. Such a spacer 150 is shown in FIG.
As shown in FIG.
It is formed so as to avoid the inside of the 5 mm circle and the corner corresponding to directly above the gate electrode 111a formed on the back surface.
Therefore, as shown in FIG. 3A, the electrode layer 120 is exposed not only from the electret material 130 but also from the spacer 150 at the corner directly above the gate electrode 111a.

The thus formed spacer 150
On this, a vibration film 140 is provided. This vibrating membrane 14
Numeral 0 is a PPS film having an electrode 141 formed on one surface by Ni vapor deposition. Then, the vibrating membrane 140
Is attached to the spacer 150 such that the electrode 141 is on the surface. Therefore, a space 160 corresponding to the thickness dimension of the spacer 150 is formed between the vibration film 140 and the electret material 130.

Further, the wafer 500 is diced into individual acoustic sensors 100.

In the manufacturing method according to the above-described embodiment, the through-hole 112 is opened at the same time as the formation of the circuits 111A to 111C. The step may be subsequent to the step of laminating the spacer 150 on 130. Next, the manufacturing method will be described with reference to FIG.

That is, first, the respective circuits 111A to 111C are formed from the back side of the wafer 500 (see FIG. 4A).

Next, an electrode layer 120 of aluminum is formed on the entire surface of the wafer 500 (see FIG. 4B). The electret material 130 is provided on the electrode layer 120.
(See FIG. 4C).

A spacer 150 is formed on the electret material 130. The spacer 150 avoids the inside of a circle having a diameter of 1.5 mm centering on the through hole 112 to be opened in a subsequent step and a corner corresponding to a position directly above the gate electrode 111a formed on the back surface. It is formed.

After the spacer 150 is formed, a through hole 112 is formed in the center portion of one acoustic sensor 100 by ultrasonic processing or laser processing.

The subsequent steps, that is, mounting of the vibrating film 140 on the spacer 150 and dicing of the wafer 500 are the same as the above-described manufacturing method.

In the two embodiments described above,
The description has been made on the assumption that the PPS film having the electrode 141 formed by Ni vapor deposition on one surface side of the vibration film 140 is attached to the wafer 500. However, it is also possible to form the vibration film 140 as shown in FIG.

This method is different from the above-described method in that the vibrating film 140 is divided into individual semiconductor chips 190 before being attached. First, in this method, the vibrating membrane 140
Before bonding, that is, at the time when the spacers 150 are formed, dicing is performed to divide the semiconductor chips into individual semiconductor chips 190 (see FIG. 5C). Then, fine dicing debris and the like generated by dicing are washed away in a cleaning step.

Next, the individual semiconductor chips 190 are attached to the adhesive film 300 with the spacer 150 facing upward, and an adhesive is applied to the spacer 150 with a squeegee 320 via a mask 310 (see FIG. 5D). further,
A film attached to a ring-shaped jig 330, that is, a PPS film 3 having an electrode formed on the surface by Ni vapor deposition.
40 is attached to each semiconductor chip 190 (FIG. 5
(E)). Then, the P
After cutting the PS film 340 (see FIG. 5F),
Vibration film 14 attached to individual semiconductor chip 190
0 (see FIG. 5 (G)).

In addition, even in the manufacturing method in which the vibration film 140 is divided into individual semiconductor chips 190 before attaching the vibration film 140, the through holes 11 are formed after the spacers 150 are formed.
2 can be opened by ultrasonic processing or laser processing.

Next, the acoustic sensor 1 thus configured
The semiconductor electret condenser microphone 600 using 00 will be described. The semiconductor electret condenser microphone 600 includes the acoustic sensor 100 and a case 2 that accommodates the acoustic sensor 100.
The electrode layer 120 exposed from the electret material 130 is connected to the gate electrode 111a of the FET circuit 111A via the case 200, and the through hole 112 is formed in the case 200. It communicates with the back room 230.

The case 200 includes a case body 210.
And a lid 220 attached to the case body 210
And

The case body 210 is a thin plate-shaped alumina package having a rectangular shape in a plan view, and has a ground terminal 211, an output terminal 212, a power supply terminal 213, and a gate terminal 214 formed at four inner corners. I have. The ground terminal 211 is connected to the ground electrode GND of the acoustic sensor 100.
The output terminal 212 is an output electrode OUT of the acoustic sensor 100.
The power supply terminal 213 is connected to the power supply electrode Vc of the acoustic sensor 100.
c, the gate terminals 214 are portions connected to the gate electrodes 111a of the acoustic sensor 100, respectively.

When the acoustic sensor 100 is housed in the case body 210, the acoustic sensor 100 has the electrodes 111a, Vcc, OUT, and GND mounted on the terminals 211, 212, 213, and 214 as described above. become. Therefore, the bottom surface of the acoustic sensor 100 and the case body 21
A space to be the back room 230 is formed between the bottom surface of the vehicle and the bottom surface of the vehicle.

Further, a conductive layer 215 is formed inside the case body 210. This conductive layer 215
Is a portion connecting the electrode layer 120 of the acoustic sensor 100 and the gate electrode 111a, and is connected to the gate terminal 214. The conductive layer 215 is connected to the electrode layer 120 by a bonding wire 216.

On the other hand, on the back side of the lid 220, a protruding pulse 221 is formed which comes into contact with the edge of the diaphragm 140 of the acoustic sensor 100. Therefore, when this lid 220 is attached to the case main body 210 in which the acoustic sensor 100 is stored,
A space can be formed between the diaphragm 140 and the lid 220. Also,
At the center of the lid 220, a sound hole 222 is opened. The sound waves are transmitted to the diaphragm 140 through the sound holes 222.

The volume of the space 160 between the electret material 130 and the vibration film 140 changes due to the vibration of the vibration film 140. This change in volume is caused by the electret material 13
This results in a change in the capacitance of a capacitor constituted by 0 and the electrode 141 of the vibrating membrane 140, and as a result, a change in voltage is output.

The output voltage is applied to the bonding wire 21
6, input to the gate electrode 111a of the acoustic sensor 100 via the conductive layer 215 and the gate terminal 2214;
The signal is output from the output electrode OUT via the ET circuit 111A and the like.

Although the above-described acoustic sensor 100 has been described as being used for the semiconductor electret condenser microphone 600, it is needless to say that the acoustic sensor 100 can also be applied as a pressure sensor or an acceleration sensor.

[0039]

The acoustic sensor according to the present invention is formed by laminating a semiconductor chip on which necessary electronic circuits are formed, an electrode layer formed on the surface of the semiconductor chip, and avoiding a part of the electrode layer. It has an electret material and a vibrating membrane provided at a predetermined interval between the electret materials.

In such an acoustic sensor, an electronic circuit necessary for amplification and the like is formed integrally with an electret material or the like. If this acoustic sensor is used, a compact and multifunctional semiconductor electret condenser microphone can be obtained. Can be.

Further, the method for manufacturing an acoustic sensor according to the present invention includes a step of forming an electronic circuit necessary for a wafer, a step of forming an electrode layer on the surface of the wafer, and an electret avoiding a part of the electrode layer. A step of laminating a material, a step of laminating a spacer on the electret material, a step of mounting a diaphragm on the spacer with a predetermined interval between the electret material, and an individual acoustic sensor And a dividing step.

According to this manufacturing method, the acoustic sensor as described above can be obtained.

Further, another method of manufacturing an acoustic sensor according to the present invention includes a step of forming an electronic circuit necessary for a wafer, a step of forming an electrode layer on a surface of the wafer, and a step of avoiding a part of the electrode layer. Stacking an electret material, stacking a spacer on the electret material, dicing the wafer into individual semiconductor chips,
Washing the individual semiconductor chips, and arranging the washed individual semiconductor chips with the spacers on top,
A step of applying an adhesive to the spacers of the arranged individual semiconductor chips, a step of attaching one film to be a vibrating film to the spacers of the individual semiconductor chips using the adhesive, and cutting the film. And forming a vibrating membrane.

According to this manufacturing method, it is possible to manufacture a better acoustic sensor without damaging the vibrating membrane or attenuating the electret material due to washing with pure water after dicing. .

Further, in the manufacturing method in which the through holes are formed after the spacers are formed, it is not necessary to avoid the through holes when forming the electrode layer and the electret material, and the through holes can be formed on the entire surface. Has the effect of being simplified.

Further, a semiconductor electret condenser microphone according to the present invention includes the acoustic sensor and a case for housing the acoustic sensor, and the electrode layer exposed from the electret material is connected to the electronic layer via the case. It is connected to the electrodes of the circuit.

Therefore, this semiconductor electret condenser microphone can be made smaller and more multifunctional than before by using the acoustic sensor.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view of an acoustic sensor according to an embodiment of the present invention.

FIG. 2 is a schematic cross-sectional view showing each step of a method for manufacturing an acoustic sensor according to an embodiment of the present invention.

3A and 3B are drawings of the acoustic sensor according to the embodiment of the present invention in the process of being manufactured, wherein FIG. 3A is a schematic plan view and FIG. 3B is a schematic bottom view.

FIG. 4 is a schematic cross-sectional view showing each step of a method for manufacturing an acoustic sensor according to another embodiment of the present invention.

FIG. 5 is a schematic explanatory view showing another method for manufacturing the acoustic sensor according to the embodiment of the present invention.

FIG. 6 is a schematic sectional view of a semiconductor electret condenser microphone according to an embodiment of the present invention.

FIG. 7 is a drawing of a case main body of a case used for a semiconductor electret condenser microphone according to an embodiment of the present invention, wherein FIG. 7A is a schematic perspective view from the front side, and FIG. It is a schematic perspective view from the bottom surface side. It is.

FIG. 8 is a schematic sectional view of a conventional electret condenser microphone.

[Explanation of symbols]

 Reference Signs List 100 acoustic sensor 110 semiconductor chip 112 through hole 120 electrode layer 130 electret material 140 vibrating film 160 interval

Claims (6)

[Claims] Claims 1. A required electronic circuit is formed,
A semiconductor chip in which a through-hole is opened to avoid the electronic circuit, an electrode layer formed on the surface of the semiconductor chip so as to avoid the through-hole, and a part of the electrode layer and the through-hole to avoid the through-hole; An acoustic sensor comprising: an electret material provided; and a vibrating membrane provided at a predetermined interval between the electret material. 2. forming a necessary electronic circuit on the wafer and opening a through hole avoiding the electronic circuit;
Forming an electrode layer on the surface of the wafer avoiding the through hole, laminating an electret material avoiding a part of the electrode layer and the through hole, and laminating a spacer on the electret material Manufacturing an acoustic sensor, comprising the steps of: attaching a vibrating membrane with a predetermined interval between the electret material on the spacer; and dividing the diaphragm as individual acoustic sensors. Method. 3. A step of forming an electronic circuit necessary for the wafer, a step of forming an electrode layer on a surface of the wafer, and a step of stacking an electret material avoiding a part of the electrode layer.
A step of laminating a spacer on the electret material, a step of forming a through-hole penetrating the wafer, the electrode layer and the electret material while avoiding the electronic circuit, and a predetermined process between the electret material on the spacer. A method of manufacturing an acoustic sensor, comprising the steps of: attaching a vibrating membrane at intervals of; and dividing the individual acoustic sensors. 4. A step of forming necessary electronic circuits on the wafer and opening through holes avoiding the electronic circuits.
Forming an electrode layer on the surface of the wafer avoiding the through hole, laminating an electret material avoiding a part of the electrode layer and the through hole, and laminating a spacer on the electret material A step of dicing the wafer into individual semiconductor chips, a step of cleaning the individual semiconductor chips, a step of arranging the washed individual semiconductor chips with the spacers on top, and a step of arranging the individual semiconductor chips. A step of applying an adhesive to the spacer of the chip, a step of attaching one film to be a vibrating film to the spacer of each semiconductor chip using the adhesive, and a step of cutting the film to form a vibrating film A method for manufacturing an acoustic sensor, comprising: 5. A step of forming an electronic circuit necessary for a wafer, a step of forming an electrode layer on a surface of the wafer, and a step of stacking an electret material avoiding a part of the electrode layer.
Laminating a spacer on the electret material, forming a through-hole through the wafer, electrode layer and electret material avoiding the electronic circuit, and dicing the wafer into individual semiconductor chips. Washing the individual semiconductor chips, arranging the washed individual semiconductor chips with the spacers facing upward, applying an adhesive to the spacers of the arranged individual semiconductor chips, and applying the adhesive A method for manufacturing an acoustic sensor, comprising: a step of attaching one film to be used as a vibrating film to spacers of individual semiconductor chips; and a step of cutting the film to form a vibrating film. 6. An acoustic sensor according to claim 1, and a case accommodating the acoustic sensor, wherein the electrode layer exposed from the electret material is connected to an electrode of the electronic circuit via the case. A semiconductor electret condenser microphone characterized by being made.