KR100675023B1 - Condenser microphone and packaging method for the same - Google Patents

Abstract

A condenser microphone and a packaging method for the same are provided to reduce a processing cost and a manufacturing cost by bonding a PCB and a metallic case with an adhesive without a curling process. A metallic case(110) includes a sound hole. A MEMS(Micro Electro Mechanical System) microphone chip(10) is used for converting sound received through the sound hole to an electrical signal. An ASIC(Application Specific Integrated Circuit) chip(20) includes a voltage pump for providing a voltage to be applied to the MEMS microphone chip and a buffer IC for amplifying the electrical signal of the MEMS microphone chip. The MEMS microphone chip and the AISC chip are mounted on a PCB(Printed Circuit Board)(120). A connective pattern is formed on the PCB in order to be bonded with the metallic case. A fixing unit fixes the metallic case to the PCB. An adhesive(140) is used for attaching the PCB and the metallic case to each other.

Description

CONDENSER MICROPHONE AND PACKAGING METHOD FOR THE SAME}

1 is a side cross-sectional view of a first embodiment of a silicon condenser microphone according to the present invention;

2 is an exploded perspective view of a first embodiment of a silicon condenser microphone according to the present invention;

3 is an example showing a MEMS chip structure of a silicon condenser microphone according to the present invention;

4 is a circuit diagram of a silicon condenser microphone according to the present invention;

5 is a flowchart illustrating a packaging procedure of a silicon condenser microphone according to the present invention;

6 is an exploded perspective view of a second embodiment of a silicon condenser microphone according to the present invention;

7 is an exploded perspective view of a third embodiment of a silicon condenser microphone according to the present invention;

8 is a separation attempt of a fourth embodiment of a silicon condenser microphone according to the present invention;

9 is a side cross-sectional view of a sixth embodiment in which connection terminals are formed on a component surface according to the present invention;

10 is a diagram illustrating a conventional concept of packaging a condenser microphone.

* Explanation of symbols for main parts of the drawings

10: MEMS chip 20: ASIC chip for special purpose

100,200: microphone 110,210: case

112, 212: sound hole 120, 220: substrate

121,221: connection pattern 123,125: connection terminal

124: through hole 130: available contact

140: adhesive 150: acoustic resistor

310: main PCB

The present invention relates to a condenser microphone, and more particularly to a method for packaging a condenser microphone and a condenser microphone for joining the case of the microphone to the PCB.

In general, a condenser microphone widely used in a mobile communication terminal or an audio device includes a voltage bias element, a diaphragm / backplate pair forming a capacitor C that changes in response to sound pressure, and a buffer for output signal. It consists of a field effect transistor (JFET). The conventional condenser microphone inserts a diaphragm, spacer ring, insulation ring, back plate, and conduction ring in one case, and finally inserts a PCB with circuit components and bends the end of the case to the PCB side. It consisted of an assembly.

However, the curling method of bending the end of the case while applying pressure to the PCB side has a problem that affects the shape or acoustic characteristics of the final product according to the pressure during the process and the tolerance of the parts. That is, when the pressing force is insufficient in the currying process, the sound pressure leaks between the case and the PCB, and the sound quality deteriorates. When the pressing force is excessive during the currying, the surface to be cut is torn or the internal parts are deformed, resulting in acoustic There was a problem that the characteristics are distorted.

In order to solve this problem, the case joint structure of the condenser microphone and its manufacturing method have been disclosed in Korean Patent Laid-Open Publication No. 10-2004-0072099.

As shown in FIG. 9, the prior art disclosed in Korean Patent Publication No. 10-2004-0072099 includes a case 30, a diaphragm, a spacer, a bipolar plate, an injection molded product, a connection ring, and a substrate 40. The open end of the case 30 is bent outward to form the connecting piece 31 in an annular shape along the end, and the edge of the surface of the substrate 40 opposite the connecting piece 31 of the case 30. After the conductive metal is plated to form the welding region 41, the components are sequentially installed inside the case 30, and the joint pieces 31 of the case and the welding region 41 of the substrate are interviewed. The case and the substrate are pressurized with two electrodes (+ electrode and-electrode) to supply electricity instantaneously in a compressed state, so that the welding region 41 formed on the substrate and the connection piece 32 of the case are melted to connect the case. To bond the piece 31 and the welding area 41 of the substrate It is.

However, in the case where the welding area of the case and the welding area of the substrate is entirely welded, deformation and stress are generated in the components due to the heat generated during welding, and it is difficult to install and operate the electrodes, which makes the welding construction difficult. have.

On the other hand, as a technology recently used for the integration of micro devices, there is a semiconductor processing technology using micromachining. This technology, called MEMS (Micro Electro Mechanical System), can produce micro sensors, actuators, and electromechanical structures in micrometers using micromachining technology using semiconductor processing, especially integrated circuit technology. MEMS chip microphones manufactured using this micromachining technology are capable of miniaturization, high performance, multifunction, integration through ultra-precision micromachining, and have the advantage of improving stability and reliability.

Therefore, a new packaging technology for efficiently bonding a case and a substrate is required not only for a conventional condenser microphone but also a silicon condenser microphone using MEMS technology.

The present invention has been proposed to solve the above problems of the prior art, and an object thereof is to provide a method for packaging a condenser microphone and a condenser microphone, thereby joining the case of the microphone with a substrate and an adhesive.

Another object of the present invention is to provide a method of packaging a condenser microphone and a condenser microphone according to which the microphone is fixed to the substrate and then bonded with an adhesive to prevent the movement of the case when the case of the microphone is bonded with the substrate and the adhesive. .

Another object of the present invention is to fix the end of the metal case to the substrate on which the MEMS microphone component is seated by laser welding, and then bonded with an adhesive to prevent the occurrence of defects, improve the bonding strength, such as electromagnetic noise To provide a silicon condenser microphone resistant to external noise and a packaging method therefor.

In order to achieve the above object, the microphone of the present invention includes a metal case in which a sound hole is formed, a MEMS microphone chip, a special purpose semiconductor (ASIC) chip having a voltage pump and a buffer IC. A board on which the mounting pattern is mounted, and a connection pattern for joining the metal case is formed; Fixing means for fixing the metal case to the substrate; And an adhesive applied and cured around the entire bonding surface of the metal case and the substrate fixed by the fixing means to bond the metal case and the substrate.

In addition, the microphone packaging method of the present invention in order to achieve the above object, a step of mounting a substrate on which a MEMS chip and a special purpose semiconductor (ASIC) chip is mounted and a connection pattern is formed; Injecting a metal case; Aligning the metal case with the connection pattern of the substrate; Welding and fixing the end portion of the metal case and the connection pattern of the substrate; Bonding an entire circumference of the connection surface of the fixed metal case and the substrate with an adhesive; And curing the adhesive.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

[First Embodiment]

1 is a side cross-sectional view of a first embodiment according to the present invention, FIG. 2 is an exploded perspective view of the first embodiment according to the present invention, and FIG. 3 is an example showing the structure of a MEMS chip microphone used in the present invention. 4 is a circuit diagram of a silicon condenser microphone according to the present invention.

As shown in FIGS. 1 and 2, the first embodiment of the present invention uses a cylindrical metal case 110 as a laser on a PCB substrate 120 on which a MEMS chip 10 and an ASIC chip 20 are mounted. After contact is fixed to the case 110 is bonded to the PCB substrate 120 with an adhesive 140. Here, the adhesive 140 may be a conductive epoxy, non-conductive epoxy, silver paste, silicon, urethane, acrylic, cream solder and the like.

1 and 2, a MEMS chip 10 and an ASIC chip 20 are mounted on a PCB substrate 120, and a circular connection pattern 121 is formed at a portion in contact with the metal case 110. It is. Although not shown in the drawings, if necessary, a capacitor or a resistor for electromagnetic shielding or ESD shielding may be mounted together.

Since the size of the PCB substrate 120 is larger than that of the metal case 110, a connection pad or a connection terminal for connecting to an external device can be freely disposed on a wide PCB surface, and the connection pattern 121 is a general PCB. After raising the copper foil through the manufacturing process, it is formed by plating nickel (Ni) or gold (Au). In this case, various substrates such as a PCB substrate, a ceramic substrate, an FPCB substrate, and a metal PCB substrate may be used as the substrate 120.

The metal case 110 has a cylindrical shape in which a connection surface of the PCB substrate 120 is opened to mount chip components therein, and an acoustic hole 112 is formed on an upper surface thereof so that sound can be introduced therein. The metal case 110 may be made of brass, copper, stainless steel, aluminum, nickel alloy, or the like, and may be used by gold or silver plating. The metal case 110 may have various shapes such as round or square. .

After aligning the metal case 110 with the connection pattern 121 of the PCB substrate 120, the case 110 is welded by welding a soluble welding point 130, which is a part of the connection portion, with a laser using a laser processing machine (not shown). ) And the substrate 120 are first fixed, and then the adhesive 140 is applied around the entire surface of the joint to complete the microphone package. Here, the 'weld welding' is not welding the entire surface where the case 110 and the PCB 120 meet, but one or more places (this is called an available welding point) to fix the case 110 and the PCB 120, Preferably two to four spot welding). In this way, the junction formed between the case 110 and the PCB 120 by tack welding is referred to as the tack weld 130, and the case 110 is fixed to the PCB 120 by the tack welding 130. When the case 110 is adhered to the case 120 with the adhesive 140 or the case 110 does not move in the curing process, the bonding may be performed at the correct position. In addition, the connection pattern 121 is connected to the ground terminal 125, and when the metal case 110 is adhered thereto, there is an advantage of easily removing noise by blocking the inflow of external noise.

As shown in FIG. 1, the microphone assembly in which the packaging is completed is bonded to the adhesive pattern 140 after the connection pattern 121 of the PCB substrate 120 and the metal case 110 are fixed by the welding of the laser. The space 150 between the metal case 110 and the PCB substrate 120 serves as an acoustic chamber.

At least two or more connection terminals 123 and 125 for connecting to an external device may be formed on the bottom surface of the PCB substrate 120, and each connection terminal 123 and 125 may be connected to the chip component surface through the through hole 124. Can be electrically conductive. Particularly, in the embodiment of the present invention, when the connection terminals 123 and 125 are formed to the periphery of the PCB substrate 120, the rework operation may be easily performed by approaching the electric iron through the exposed surface.

As shown in FIG. 3, the MEMS chip 10 forms the back plate 13 on the silicon wafer 14 by using MEMS technology, and then vibrates 11 with spacers 12 therebetween. This structure is formed. Since the manufacturing technology of the MEMS chip 10 is already known, further description thereof will be omitted.

The special purpose semiconductor (ASIC) chip 20 is connected to the MEMS chip 10 to process electrical signals. As shown in FIG. 4, the MEMS chip 10 provides a voltage to operate as a condenser microphone. It is composed of a buffer IC 24 for amplifying or impedance matching the electrical sound signal sensed through the voltage pump 22 and the MEMS chip 10 to provide to the outside through the connection terminal. Here, the voltage pump 22 is a DC-DC converter, and the buffer IC 24 may use an analog amplifier, an analog-to-digital converter (ADC), or the like. In the circuit diagram of FIG. 4, the capacitor symbol "C0" represents an electrical equivalent circuit for the MEMS chip 10, and the MEMS microphone package 100 is connected to an external device through three connection terminals Vdd, GND, and Output. It can be seen that.

In the exemplary embodiment of the present invention, the fixing of the case 110 to the PCB substrate 120 has been described by using a welding process using a laser as an example, but the case 110 is fixed to the substrate 120 by another method such as soldering or punching. Also, the adhesive 140 may use conductive or nonconductive epoxy, silver paste, silicone, urethane, acrylic, cream solder, or the like.

[Packaging Method]

5 is a flowchart illustrating a packaging procedure of a silicon condenser microphone according to the present invention.

According to the present invention, a method of packaging a silicon condenser microphone is shown in FIG. 5, in which the step of inserting the substrate 120 (S1), the MEMS component 10, and the special purpose semiconductor (ASIC) chip 20 are performed. Step (S2) of mounting on the substrate 120, the step (S3) of inserting the metal case 110, the step (S4) of aligning the case 110 to the connection pattern 121 of the substrate, the case 110 Fixing the end portion and the connection pattern 121 of the substrate by welding or the like (S5), after fixing the case 110 to the substrate 120, the entire circumference of the portion where the substrate 120 and the case 110 meet It is composed of a step (S6) of bonding the case 110 and the substrate 120 by applying with the adhesive 140, the step (S7) of curing the adhesive 140.

In this case, various substrates such as a PCB substrate, a ceramic substrate, an FPCB substrate, and a metal PCB substrate may be used as the substrate 120, and a connection pattern 121 for connecting to the metal case 110 is formed on the substrate 120. have.

In addition, the material of the metal case 110 may be brass, copper, stainless steel, aluminum, nickel alloy, and the like, and may be used by gold or silver plating, and the shape of the metal case 110 may be round or square. Do.

In step 5 (S5) of fixing the metal case 110 to the substrate 120, welding or punching may be performed by laser welding or soldering, and as the adhesive 140, conductive or non-conductive epoxy may be used. After bonding to the adhesive 140, the adhesive 140 is cured by natural curing, ultraviolet curing, thermal curing, or the like to complete the manufacture of the microphone.

According to the packaging method of the present invention as described above, the metal case 110 is welded and fixed to the substrate 120 by a laser, and then bonded and cured by an adhesive 140 to increase the bonding force (electrical connection force and sealing performance) to improve sound quality. Improved, strong against external noise, in particular, there is an advantage that can significantly reduce the overall manufacturing cost by reducing the occurrence of defects and reduce the process cost.

Second Embodiment

Figure 6 is an exploded perspective view of a second embodiment according to the present invention, the second embodiment of the present invention is a metal case 210 of the cylindrical tube is welded to the PCB substrate 220 by laser welding and then fixed with an adhesive 140 Hardened by.

Referring to FIG. 6, a MEMS chip 10 and an ASIC chip 20 are mounted on a PCB substrate 220, and a rectangular connection pattern 221 is formed at a portion in contact with the metal case 210. The connection pattern 221 is formed of a copper foil film by a conventional PCB pattern technique.

The metal case 210 has a rectangular cylindrical shape in which a surface connected to the PCB substrate 220 is opened, and an acoustic hole 212 is formed on the upper surface thereof so that sound can be introduced therethrough.

After aligning the metal case 210 to the connection pattern 221 of the PCB substrate 220, a laser welding machine is used to weld one connection part at each surface as shown in FIG. 6 using a laser processing machine (not shown). The contact 130 is formed, the adhesive 140 is applied to the entire circumference of the connection surface, and then cured to complete the packaging. Here, the connection pattern 221 is connected to the ground terminal, when the metal case 210 is welded there, there is an advantage that it is easy to remove the noise by blocking the inflow of external noise.

The microphone assembly having the packaging as described above is the same as that shown in FIG. 1, and thus, further description is omitted to avoid repetition.

Third Embodiment

Figure 7 is an exploded perspective view of a third embodiment according to the present invention, the third embodiment of the present invention is a PCB having a cylindrical metal case 110 'formed with a wing 116 protruding in the shape of the letter "b" The substrate 120 is hardened by welding with a laser and then bonded with an adhesive 140 to cure.

Referring to FIG. 7, a MEMS chip 10 and an ASIC chip 20 are mounted on a PCB substrate 120, and a circular connection pattern 121 is formed at a portion in contact with the metal case 110 ′. . Since the size of the PCB substrate 120 is larger than that of the metal case, a connection pad or connection terminal for connecting to an external device can be freely disposed on a wide PCB surface, and the connection pattern 121 is manufactured through a general PCB manufacturing process. It is preferable to plate nickel (Ni) and gold (Au) after raising copper foil. In the third embodiment of the present invention, the connection pattern 121 is preferably wider than the first embodiment corresponding to the wing 116 formed in the metal case.

The metal case 110 ′ of the third embodiment has a cylindrical shape in which a connection surface is opened to the PCB substrate 120, and an acoustic hole 112 is formed on an upper surface of the metal case 110 ′, and an end surface of the case body 114. The wing 116 protruding outward is formed.

The end wing 116 of the metal case 110 'is aligned with the connection pattern 121 of the PCB, and then welded using a laser processor (not shown) to bond the case 110' and the substrate 120 to each other. After fixing, the adhesive 140 is completed to complete the packaging.

[Example 4]

FIG. 8 is an exploded perspective view of a fourth embodiment of a silicon condenser microphone according to the present invention. The fourth embodiment of the present invention is a rectangular cylindrical metal case having a wing 216 protruding at the end of a “b” shape. 210 ') is tack-welded to the PCB substrate 220 with a laser, and then bonded with an adhesive 140 to harden.

Referring to FIG. 8, a MEMS chip 10 and an ASIC chip 20 are mounted on a PCB substrate 220, and a rectangular connection pattern 221 is formed at a portion in contact with the metal case 210 ′. . Since the size of the PCB 220 is larger than that of the metal case 210 ', a connection pad or a connection terminal for connecting to an external device can be freely disposed on a wide PCB surface, and the connection pattern 221 is a general PCB. It is preferable to plate nickel (Ni) or gold (Au) after raising copper foil through a manufacturing process. In the fourth embodiment of the present invention, the connection pattern 221 is preferably wider than the second embodiment corresponding to the wing 216 formed at the end of the body 214 of the metal case 210 '.

The metal case 210 ′ is a rectangular cylindrical shape in which a connection surface of the PCB substrate 220 is opened, and an acoustic hole 212 is formed on the upper surface of the metal case 210 ′ so that sound is introduced into the upper surface of the metal case 210 ′. A protruding wing 216 is formed.

After aligning the end blades 216 of the metal case to the connection pattern 221 of the PCB, and then tack-welded with a laser processor (not shown) to fix the case 210 'and the substrate 220, the adhesive 140 To complete the packaging.

[Example 5]

9 is a side sectional view of a fifth embodiment of a silicon condenser microphone according to the present invention.

In the silicon condenser microphone according to the fifth embodiment of the present invention, after the cylindrical metal case 110 is fixed to the substrate 120 wider than the metal case by tack welding, the silicon condenser microphone is bonded with the adhesive 140 and the component surface of the substrate ( The terminal 120a is provided with a connection terminal 122 for connecting with the connection pad 320 of the main PCB 310 of the product in which the microphone is to be used. In the sixth embodiment of the present invention, although four connection terminals are taken as an example, this is only one example, and at least two or more eight may be formed, and reference numeral 130 denotes a soluble welding point by tack welding. In addition, when the connection terminal 122 extends to the side wall portion of the substrate or extends to the opposite side of the component surface following the side wall portion, heat transfer such as an electric iron may be improved, and thus the rework operation may be more convenient.

In addition, the main PCB 310 of the product on which the silicon condenser microphone according to the sixth embodiment of the present invention is to be mounted has a circular insertion hole 310a so that the case 110 of the silicon condenser microphone can be mounted, and the microphone The connection pad 320 is formed to correspond to the connection terminal 122 formed on the substrate 120.

In the microphone of the fifth embodiment in which the silicon condenser microphone is mounted on the main PCB 310, the metal case 110 protruding from the center portion of the substrate component surface 120a may have the main PCB (As shown in FIG. 9). In addition to being inserted into the insertion hole 310a of the 310, the connection pad 320 of the main PCB and the connection terminal 122 of the microphone are connected by the soldering 330.

Therefore, according to the mounting method of the present invention, since the case 110 portion protruding from the substrate of the microphone is inserted into the insertion hole 310a formed in the main PCB 310, the overall height t after the mounting of the component surface of the microphone is changed. The connection terminal is formed on the opposite side, which is lower than the overall height when mounted on the main PCB, so that the component mounting space of the product can be efficiently used.

Inside the metal case of the silicon condenser microphone, the MEMS chip 10 and the ASIC chip 20 are mounted on the substrate 120 and contacted with the metal case 110, as shown in the cross-sectional view of FIG. 9. A circular connection pattern 121 is formed in the hole.

  In this case, various substrates such as a PCB substrate, a ceramic substrate, an FPCB substrate, a metal PCB substrate, and the like may be used as the substrate 120, and the metal case 110 has an acoustic hole 112 formed therein for inflow of sound. It is made of brass, copper, stainless steel, aluminum, nickel alloy, etc. and can be used by plating with gold or silver.

As shown in the side cross-sectional view of FIG. 9, when the connection terminal 122 extends to the opposite side of the component surface via the side wall of the substrate, heat transfer such as an electric iron may be improved, and thus, the rework operation may be easier. Although not shown in the drawing, the connection terminal 122 may extend only to the sidewall of the substrate.

In the above embodiment, only the silicon condenser microphone has been described as an example, but the present invention typically inserts a diaphragm, a spacer ring, an insulating ring, a back plate, and an energizing ring into a case, and finally, joins a PCB and a case in which circuit components are mounted. The same can be applied to condenser microphones having a structure.

As described above, in the present invention, the metal case is temporarily welded and fixed to a substrate by a laser, and then bonded by an adhesive, so that the case is fixed at the time of bonding, and no defect is generated. There is an advantage that can significantly reduce the overall manufacturing cost by reducing the process cost.

In addition, by eliminating the curling process, which is a process of joining a metal case and a PCB in a conventional microphone manufacturing process, the electrical conduction characteristics between the case and the PCB can be improved by bonding the metal case to the PCB board on which the capacitor microphone parts are mounted. In addition, by sealing the sound pressure from the outside can be improved acoustic properties.

In addition, since the shape of the PCB is not limited by the case, it is possible to freely design the PCB used in the microphone, and thus various types of terminals can be formed, and as it is possible to work without the physical force applied during curling as in the prior art, It is possible to apply a thin PCB, the use of such a thin PCB can lower the height of the product can be produced a thinner microphone.

Although the above has been described with reference to a preferred embodiment of the present invention, those skilled in the art will be variously modified and changed within the scope of the present invention without departing from the spirit and scope of the invention described in the claims below. I can understand that you can.

Claims (14)

In the silicon condenser microphone, A metal case in which a sound hole is formed; MEMS microphone chip for converting the sound introduced through the sound hole into an electrical signal; A special purpose semiconductor (ASIC) chip having a voltage pump for providing a voltage to be applied to the MEMS microphone chip and a buffer IC for amplifying an electrical signal of the MEMS microphone chip; A substrate on which the MEMS microphone chip and the special purpose semiconductor chip are mounted, and a connection pattern for bonding to the metal case is formed; Fixing means for fixing the metal case to the substrate; And And an adhesive applied around the entire bonding surface of the metal case and the substrate fixed by the fixing means to bond the metal case and the substrate. The method of claim 1, wherein the fixing means, A silicon condenser microphone, wherein the silicon condenser microphone is a soluble welding point formed by laser welding or welding. The method of claim 1, wherein the adhesive Silicon condenser microphone, characterized in that any one of conductive epoxy, non-conductive epoxy, silver paste, silicon, urethane, acrylic, cream solder. The method of claim 1, wherein the metal case A silicon condenser microphone, characterized by a cylindrical or square cylinder type. delete delete The method of claim 1, wherein the substrate Silicon condenser microphone, characterized in that any one of the PCB substrate, ceramic substrate, FPCB substrate, metal PCB substrate. The method of claim 1, wherein the metal case is made of a material Silicon condenser microphone, characterized in that any one of brass, aluminum, nickel alloys. The method of claim 1, wherein the substrate A silicon condenser microphone, characterized in that a connection terminal for connecting with an external circuit is formed on the opposite surface on which the metal case is mounted. The method of claim 1, wherein the substrate Silicon condenser microphone, characterized in that the connection terminal for connecting to the external circuit formed on the surface of the metal case is mounted. In the packaging method of the silicon condenser microphone, A MEMS chip for converting sound into an electrical signal and a special purpose semiconductor (ASIC) chip for supplying a voltage for driving the MEMS chip and for amplifying an electric signal of the MEMS chip are mounted and a connection pattern is mounted. Injecting the formed substrate; Injecting a metal case; Aligning the metal case with the connection pattern of the substrate; Fixing and welding the metal case to the connection pattern of the substrate; Bonding an adhesive around the fixed connection of the metal case and the substrate; And And curing the adhesive. The method of claim 11, wherein the metal case A packaging method of a silicon condenser microphone, characterized by a cylindrical or square cylinder. The method of claim 11, wherein the soluble welding is A packaging method for a silicon condenser microphone, which is either laser welding or soldering. The method of claim 11, wherein the adhesive A method for packaging a silicon condenser microphone, which is any one of a conductive epoxy, a nonconductive epoxy, a silver paste, silicon, urethane, acrylic, and a cream solder.

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