KR20010074030A - Method for manufacturing of condenser microphone - Google Patents

Abstract

PURPOSE: A method for manufacturing a condenser microphone is provided to prevent the inferiority by the broken wires of an FET terminal and to prevent the noise and to minimize products. CONSTITUTION: In the method for manufacturing the condenser microphone, many instruments are included. A filter(41) prevents the alien materials inflow through a sound wave inflow space(39) of a case(38). An oscillating plate ring(37) maintains the space in the case(38). An oscillating plate(36) is oscillated by the inflow sound through the sound wave inflow space(39). A spacer(35) maintains the vacuum state to convey the sound oscillation. A supporter(33) prevents transforming of the whole form. A rear pole plate(34) detects the change of the capacitance according to oscillating of the oscillating plate(36). A connection ring contacts an FET gate and the rear pole plate(34). A matched and amplified circuit chip(32) is matched on a print circuit board(31) and includes an FET(Field Effect Transistor) and a capacitor.

Description

Method for manufacturing condenser microphone

The present invention relates to a condenser microphone, and more particularly, to a matching and amplifying circuit including a field effect transistor (hereinafter referred to as a "FET") and a capacitor on a wafer, and to a printed circuit board. The present invention relates to a method for manufacturing a condenser microphone suitable for direct miniaturization and improving the characteristics of the condenser microphone by direct bonding.

In general, a condenser microphone is a microphone using a change in capacitance of a parallel plate condenser. The condenser microphone is a fixed electrode and the other is a conductive diaphragm electrode. The DC voltage is applied, and the voltage generated when the capacitance is changed at the same time as the electrode gap is changed by the negative pressure is taken out as a voice signal.

The frequency characteristics are almost flat up to 30,000 Hz, high fidelity microphones, but the output is small, and has recently been widely applied to mobile communication terminals such as mobile phones, including measurement and broadcasting.

Looking at the theory and principle of operation of the condenser microphone, the so-called internal components of the condenser microphone are very precise and sensitive to external electric noise, so that the sound wave is sufficiently protected from dust and foreign matter penetration and electric noise. The inlet is laminated and sealed in a metal case formed.

When sound wave is applied to the diaphragm through the sound wave inlet, when the diaphragm vibrates, the distance change from the polar plate or the back plate occurs, that is, the distance change due to the sound wave. To understand the change in capacitance.

In general, condenser microphones are used in combination with FETs, which are impedance conversion elements, in order to match the input impedance required by the amplifier because they have low capacitance and high electrical impedance and thus cannot be used in direct connection with a general amplifier.

Here, the FET is a field effect transistor, which is an active device composed of three terminals of a source, a gate, and a drain, and a basic operation circuit of an electrostatic condenser microphone system (ECMs) by changing the current value flowing between the drain and the source as the potential of the gate changes. It can be configured to obtain an electrical signal according to the sound waves.

Condenser microphones require a voltage of several hundred volts DC external supply with a positive polarity voltage, but ECMs are a type of nonpolar condenser microphones. By accumulating, the external power supply is omitted.

Such condenser microphones can be mounted on microphones, telephones, tape records, and the like.

Hereinafter, a conventional condenser microphone will be described with reference to the accompanying drawings.

As shown in FIG. 1, the sound wave inlet 9 is perforated, and the case 8 is positioned above the case 8, and the moisture and foreign matters are introduced into the case 8 through the sound wave inlet 9. A filter 11 for preventing the filter, a diaphragm ring 7 positioned inside the case 8 and maintaining a space inside the case 8 so as to induce vibration of sound introduced through the sound wave inlet 9; Located at the bottom of the diaphragm ring (7) to vibrate the vibration plate 6 by the sound introduced through the sound wave inlet (9), and is located at the bottom of the diaphragm (6) to maintain the vacuum state to transmit the vibration of the sound Spacer 5, a support 3 which is located at the bottom of the spacer 5 to prevent and support the flow of each part, and prevents deformation of the overall shape, and the vibration plate by the spacer 5 located inside the support 3 (6) and the vacuum is maintained at a predetermined interval and the change depending on the vibration of the diaphragm A bipolar plate 4 for detecting the capacitance, a connection ring 10 located inside the support 3 and at the lower end of the bipolar plate 4, and connecting the gate of the matching FET 2 to the bipolar plate 4; And a printed circuit board (1) having a circuit wired with a conductive material, and a FET (2) bonded on the printed circuit board (1) to amplify and convert a potential change caused by a change in capacitance into an electric signal.

Here, the FET 2 is packaged and commercialized by a semiconductor company, and a process of packaging the FET 2 is as follows. First, a semiconductor company scribs a wafer to a predetermined size, and then forms a FET chip in each scribed cell. After cutting each FET chip formed on the wafer as described above, terminals of predetermined lengths are respectively bonded to gate, source, and drain portions formed on the bottom surface of the FET chip. Since each bonded FET is molded with epoxy, one FET 2 is completed.

The prior art is to manufacture a condenser microphone using the completed FET 2 as described above.

The diaphragm ring 7, the diaphragm 6, the spacer 5, the bipolar plate 4, and the support 3 are sequentially coupled in the case 8. Finally, a single condenser microphone is manufactured by coupling and fixing the printed circuit board 1, to which the FET 2 is soldered, to the bottom of the support 3 and the case 8.

Here, the process of coupling the FET 2 and the printed circuit board 1 by soldering is as follows.

First, the drain terminal, the source terminal, and the gate terminal of the FET 2 are connected to the corresponding holes provided in the printed circuit board 1, respectively, and the gate terminal of the FET 2 is connected to the bipolar plate 4. Here, the connection between the gate of the FET 2 and the bipolar plate 4 is directly connected by a point contact and a method using a connection ring 10. Recently, the connection using the connection ring 10 This method is mainly used.

In order to connect the FET 2 and the printed circuit board 1, the ends of each drain terminal, source terminal, and gate terminal are bent at a predetermined angle to face the printed circuit board 1, respectively.

Ends of the bent drain terminal, the source terminal, and the gate terminal are respectively inserted into the through holes provided in the printed circuit board 1. The drain terminal, the source terminal, and the gate terminal penetrating the printed circuit board 1 through the through hole temporarily fix the printed circuit board 1. After the manufacturing process, each bent terminal to be temporarily fixed must be bent back.

Here, the connection between the FET 2 and the printed circuit board 1 is soldered or bonded using a surface mount device (SMD).

After the connection between the FET 2 and the printed circuit board 1 is completed, the one condenser microphone is completed by coupling the printed circuit board 1 into the case 9.

The size of the condenser microphone is determined by the size of the FET 2, which is the largest factor of the size. In general, when the condenser microphone is manufactured using the FET 2 manufactured as described above, the thickness T is 1.5 mm. Up to manufacturing is possible.

However, the condenser microphone according to the related art has a problem such that the bent portion is disconnected due to repeatedly bending the drain terminal, the source terminal and the gate terminal.

In addition, the bonding of the terminals of the FET and the printed circuit board using lead causes noise due to contact resistance, and when the heat is applied to connect the wires on the back of the printed circuit board, the terminal bonded to the FET is disconnected. There is a problem that occurs.

On the other hand, there is a problem that the output of the condenser microphone is limited because it has to rely on the production method and the output of the semiconductor manufacturer that produces the FET which is the core material of the condenser microphone.

The present invention has been made to solve the above problems, FET terminal constituting the matching and amplifying circuit by directly bonding a matching and amplifying circuit chip including a FET and a capacitor formed in each cell of the wafer in a pattern on a printed circuit board It is an object of the present invention to provide a method of manufacturing a condenser microphone suitable for preventing a defect due to disconnection of a wire and for removing noise and producing a compact product.

In addition, the present invention can reduce the errors in the manufacturing process of the condenser microphone by directly bonding the matching and amplifying circuit chip including the FET and the capacitor to the pattern on the printed circuit board, and to reduce the manufacturing process time of the condenser microphone It is an object to provide a manufacturing method.

1 is a cross-sectional view showing a predetermined portion of a conventional condenser microphone.

2 is a cross-sectional view showing a predetermined portion of the condenser microphone according to the present invention.

※ Explanation of code about main part of drawing ※

31: printed circuit board 32: matching and amplifying circuit chip

33: injection molding 34: bipolar plate

35: space 36: diaphragm

37: bipolar plate ring 38: case

39: inlet 40: connection ring

41: filter

The present invention for achieving the above object is a manufacturing method of a condenser microphone having a matching, amplifying circuit chip printed circuit board including a case, diaphragm ring, diaphragm, spacer, support, bipolar plate, connection ring, FET and capacitor. Dividing a wafer into cells of a predetermined size, and forming a matching and amplifying circuit chip including a FET and a capacitor in each cell, and a corresponding position of the printed circuit board patterned by the matching and amplifying circuit chip as a conductor. Bonding the corresponding portions of the drain, the source, the gate end and the printed circuit board formed on the FET of the matching and amplifying circuit chip with a metal wire, and fixing the printed circuit board together with the matching and amplifying circuit chip. Testing the operating condition after molding the surface and the diaphragm ring, spacer, support, bipolar plate, connection ring and phase in the case And sequentially coupling the printed circuit board to which the pre-matching and amplifying circuit chips are bonded.

In the method of manufacturing a condenser microphone according to the present invention, a printed circuit board for bonding a matching and amplifying circuit chip including the FET and the capacitor is patterned with a conductive material on the upper and lower surfaces thereof, and the surface thereof is rippled with lead. It is preferable to reflow.

In the method of manufacturing a condenser microphone according to the present invention, the fixing of the FET and the printed circuit board of the matching and amplifying circuit chip may include drain, source, and gate exposed portions of the FET of the matching and amplifying circuit chip. It is preferable to adhere to the pattern.

In the manufacturing method of the condenser microphone according to the present invention, it is preferable to fix and fix with a semiconductive adhesive when fixing the FET of the matching and amplifying circuit chip and the printed circuit board.

In the manufacturing method of the condenser microphone according to the present invention, the adhesive is preferably used silver epoxy (Ag epoxy) mixed with silver (Ag) and epoxy (epoxy) in a constant ratio.

In the manufacturing method of the condenser microphone according to the present invention, it is preferable to selectively use any one of an aluminum wire and a gold wire for the wire bonding of the FET and the printed circuit board of the matching and amplifying circuit.

In the manufacturing method of the condenser microphone according to the present invention, it is preferable that the molding of the FET and the printed circuit board of the matching and amplifying circuit chip is made of epoxy resin.

In the manufacturing method of the condenser microphone according to the present invention, the epoxy resin is preferably used CR-2000, CRH-210.

In the method of manufacturing a condenser microphone according to the present invention, after molding the FET and the printed circuit board of the matching and amplifying circuit chip with epoxy resin, drying for 1 hour 10 minutes to 1 hour 50 minutes at 120 to 180 ℃. desirable.

Hereinafter, a manufacturing method of a condenser microphone according to the present invention will be described in detail with reference to the accompanying drawings.

2 is a cross-sectional view showing a predetermined portion of the condenser microphone according to an embodiment of the present invention.

Referring to Figure 2, to protect the respective parts of the condenser microphone and to maintain the appearance, the case 38 is a sound wave inlet 39 is perforated thereon, the case 38 is located outside the case 38 The filter 41 to prevent foreign matters such as moisture and dust from flowing through the sound wave inlet 39 of the filter, a diaphragm ring 37 to maintain a space in the case 38, and the diaphragm ring 37 of the filter 41. A diaphragm 36 positioned at a lower end and vibrating by sound introduced through the sound wave inlet 39, a spacer 35 positioned at a lower end of the diaphragm 36 to maintain a vacuum to transmit negative vibration; Located at the bottom of the spacer 35 to prevent and support the flow of each part, and to prevent deformation of the overall shape, and the support 33 is located inside the support 33 and a predetermined distance from the diaphragm 36 by the spacer 35 Maintains the vacuum state and positive pressure according to the vibration of the diaphragm 36 The gate plate of the FET and the gate plate 34 of the matching plate and the amplification circuit chip 32 which are located inside the support 33 and the lower side of the plate 34 and detect the change in capacitance. A connection ring 40 to be brought into contact with each other, a printed circuit board 31 having a circuit wired with a conductive material, and a FET bonded on the printed circuit board 31 to match and amplify a potential change caused by a change in capacitance with an electric signal. And a matching and amplifying circuit chip 32 including a capacitor and the like.

Here, the manufacturing method of the condenser microphone according to the present invention as described above is as follows.

First, a disk-shaped wafer (not shown) made of silicon single crystal used as a raw material of a semiconductor integrated circuit (IC) is divided into a plurality of cells. Wafer splitting is a scribing method that makes grooves on the wafer surface at regular intervals horizontally and vertically using a diamond cutter.Sawing that makes grooves on the wafer surface horizontally and vertically by rotating a wheel with a sharp knife. sawing) method. In recent years, the sawing method is mainly used, which is not rough, but can be divided more precisely. At this time, each cell of the wafer is divided into a size of 0.4mm x 0.4mm.

A matching and amplifying circuit chip 32 including a FET and a capacitor is formed in each cell of the wafer thus divided.

On the other hand, the back surface of the printed circuit board 31, the circuit of which is wired with a conductive material, is reflowed using a solder paster. Reflow of the printed circuit board 31 causes the solder to adhere to the portion that needs to be soldered.

Subsequently, the matching and amplifying circuit chip 32 formed on the wafer is fixed to the other side of the printed circuit board 31 reflowed with lead. The fixing method is fixed by adhering the gate, the drain, the source of the FET exposed to the bottom of the matching and amplifying circuit chip 32, and the corresponding position of the printed circuit board 31 using an adhesive. The adhesive uses a semiconductive material in which silver (Ag) and epoxy are mixed in an appropriate ratio.

With the matching and amplifying circuit chip 32 fixed to the printed circuit board, the drain, the source, the gate of the FET of the matching and amplifying circuit chip 32 and the corresponding of the printed circuit board 31 using aluminum wire or gold wire. Bond position. The portion bonded to the drain and the source is connected to a pattern on the bottom of the printed circuit board and connected to an external terminal for outputting a voice signal.

Some surfaces of the printed circuit board 31 bonded to the gate are electrically connected to the connection ring 40, and the connection ring 40 is connected to the bipolar plate 34 so as to be conductive.

Here, the bonding between the FET of the matching and amplifying circuit chip 32 and the printed circuit board 31 is made of aluminum wire or gold wire, the thickness of which is 30 μm, and the epoxy resins are 'CR-2000' and 'CRH-210'. ', And dried at 120 to 180 ° C for 1 hour 10 minutes to 1 hour 50 minutes to complete. It is most appropriate to set the above drying temperature and time at 150 ° C. for 1 hour 30 minutes.

After bonding the drain, the source and the gate of the FET of the matching and amplifying circuit chip 32 to the printed circuit board 31, the printed circuit board 31 and the matching and amplifying circuit chip 32 are epoxy resin. To prevent corrosion of the product and to protect the product from foreign substances.

In this way, the connection between the printed circuit board 31 and the matching and amplifying circuit chip 32 is completed, and the conductive state and the like are tested.

Subsequently, matching and amplification including the diaphragm ring 37, the diaphragm 36, the spacer 35, the support 33, the bipolar plate 34, the connection ring 40, and the FET and the capacitor in the case 38. In the circuit chip 32, the height T of the matching and amplifying circuit chip 32 is 0.2 mm, and the height T of the entire condenser microphone can be from 0.8 to 1.0 mm.

Therefore, according to the method of manufacturing a condenser microphone according to the present invention, a matching and amplifying circuit chip including a FET and a capacitor is formed on a wafer divided into cells of a predetermined size, so that the matching and amplifying circuit chip in a wafer state is directly connected to a pattern on a printed circuit board. The bonding process can significantly reduce the assembly process and the size of the product, making it possible to produce a very compact product, removing noise from soldering terminals, and matching and amplifying circuit chips due to heat generated during soldering. There is an effect that it is possible to eliminate the defect that the terminal joined to the FET is disconnected.

Although the present invention has been described in detail only with respect to the described embodiments, it will be apparent to those skilled in the art that various modifications and variations are possible within the spirit of the present invention, and such modifications and modifications belong to the appended claims.

Claims (9)

A method of manufacturing a condenser microphone having a matching and amplifying circuit chip printed circuit board including a case, a diaphragm ring, a diaphragm ring, a spacer, a support, a bipolar plate, a connection ring, a FET, and a capacitor, Dividing the wafer into cells of a predetermined size and forming a matching and amplifying circuit chip including a FET and a capacitor in each cell; Fixing the matching and amplifying circuit chip to a corresponding position on the printed circuit board patterned by a conductor; Bonding a drain, a source, a gate terminal, and a corresponding connection portion of the printed circuit board to a metal wire formed on the FET of the matching and amplifying circuit chip; Molding an surface of a printed circuit board together with the matching and amplifying circuit chip and then testing an operating state; And Sequentially coupling a diaphragm ring, a spacer, a support, a bipolar plate, a connection ring, and a printed circuit board bonded with the matching and amplifying circuit chip in the case; Method for producing a condenser microphone, characterized in that it comprises a. The method of claim 1, The printed circuit board for bonding the matching and amplifying circuit chip including the FET and the capacitor, the circuit is patterned with a conductive material on the upper and lower surfaces, respectively, and the surface is reflowed with lead. The method of claim 1, The fixing of the FET and the printed circuit board of the matching and amplifying circuit chip is to manufacture the condenser microphone, characterized in that for bonding the drain, source, and gate exposed portion of the FET of the matching and amplifying circuit chip to the circuit pattern of the printed circuit board. Way. The method according to claim 1 or 3, And a semi-conductive adhesive for fixing the FET and the printed circuit board of the matching and amplifying circuit chip. The method of claim 4, wherein The adhesive is a manufacturing method of the condenser microphone, characterized in that the use of silver epoxy (Ag epoxy) mixed with a certain ratio of silver (Ag) and epoxy (epoxy). The method of claim 1, The wire bonding of the FET and the printed circuit board of the matching and amplifying circuit selectively uses any one of aluminum wire or gold wire. The method of claim 1, And the molding of the FET and the printed circuit board of the matching and amplifying circuit chip is made of epoxy resin. The method of claim 7, wherein The epoxy resin is CR-2000, CRH-210 using the manufacturing method of the condenser microphone, characterized in that. The method of claim 7, wherein And molding the FET and the printed circuit board of the matching and amplifying circuit chip with an epoxy resin and drying at 120 to 180 ° C. for 1 hour 10 minutes to 1 hour 50 minutes.