KR100722689B1 - Silicon condenser microphone having additional back chamber - Google Patents

Abstract

The present invention discloses a silicon condenser microphone having an additional back chamber to improve acoustic characteristics.

According to the present invention, a silicon condenser microphone having an additional back chamber includes a chamber barrel 150 for forming an additional back chamber 152 on a PCB substrate 140 on which connection terminals 142 and 144 and a conductive pattern 141 are formed. After mounting and mounting a special purpose semiconductor (ASIC) chip 120 for driving an electrical signal of the MEMS chip 110, the MEMS chip 110 is attached to the chamber 150, and the case 130 is a PCB. It has a structure attached to 140.

Therefore, the present invention has an effect of improving the sensitivity and noise, such as THD (Total Harmonic Distortion), by increasing the insufficient back chamber space of the MEMS chip itself by placing a chamber for forming an additional back chamber at the bottom of the MEMS chip. There is.

MEMS, Condenser Microphone, Case, PCB, Back Chamber, Addition, Expansion, Acoustic

Description

SILICON CONDENSER MICROPHONE HAVING ADDITIONAL BACK CHAMBER}

1 illustrates an example of a general MEMS chip structure used in a silicon condenser microphone;

2 is a side cross-sectional view showing a conventional silicon condenser microphone using a MEMS chip;

3 is a side cross-sectional view showing a silicon condenser microphone with an additional back chamber in accordance with the present invention;

Figure 4 shows an example of an additional back chamber structure of the square cylinder according to the present invention,

5 shows an example of a cylindrical additional bag chamber structure according to the present invention;

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

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

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

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

Fig. 10 is a side sectional view of a fifth embodiment in which connection terminals are formed on a component surface according to the present invention;

* Explanation of symbols for main parts of the drawings

110: MEMS chip 120: special purpose semiconductor (ASIC) chip

130-134: Case 130a-134a: Sound hole

140: PCB 141: conductive pattern

142,144: Connection terminal 146: Through hole

150,150 ', 150 ": chamber barrel 150a: through hole

152: additional back chamber 162: welding point

164: adhesive

The present invention relates to a condenser microphone, and more particularly to a silicon condenser microphone having an additional back chamber to improve acoustic characteristics.

In general, condenser microphones widely used in mobile communication terminals and audio, etc. buffer the output signal, the diaphragm / back plate pair forming a capacitor (C) that changes in response to sound pressure (sound pressure), and the output signal Field effect transistor (JFET). In this conventional condenser microphone, the diaphragm, spacer ring, insulation ring, back plate, and conduction ring are sequentially inserted in one case. Finally, the circuit part is mounted with a PCB and the end of the case is bent to the PCB side. The assembly was completed.

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 microphone fabricated using this micromachining technology is stable by miniaturization, high performance, multifunctionalization, integration of conventional diaphragm and traditional microphone parts such as spacer ring, insulation ring, back plate, energizing ring through ultra-precision micro machining. And there is an advantage that can improve the reliability.

1 illustrates an example of a general MEMS chip structure used in a silicon condenser microphone. Referring to FIG. 1, in the MEMS chip 10, a back plate 13 is formed on a silicon wafer 14 using MEMS technology, and then a vibrating membrane 11 is formed with a spacer 12 interposed therebetween. It is structured. A sound hole 13a is formed in the back plate 13, and the MEMS chip 10 is manufactured by conventional micromachining techniques and semiconductor chip manufacturing techniques.

Figure 2 is a side cross-sectional view showing a conventional silicon condenser microphone implemented using such a MEMS chip. Referring to FIG. 2, the conventional silicon condenser microphone 1 is a case 30 in which a sound hole 30a is formed after mounting a MEMS chip 10 and a special purpose semiconductor (ASIC) chip 20 on a PCB 40. Built in and assembled.

However, as shown in FIG. 2, the back chamber 15 of the silicon condenser microphone 1 is formed by the MEMS chip 10. Since the MEMS chip 10 is a semiconductor chip, the back chamber 15 is very small in size. The space of 15) becomes extremely narrow, and there is a problem in that the sound quality of the microphone is deteriorated.

The present invention has been proposed to solve the above problems, and an object thereof is to provide a silicon condenser microphone having an additional back chamber to improve acoustic characteristics.

In order to achieve the above object, the microphone of the present invention includes a case in which an acoustic hole is formed; A substrate having a chamber passage, an MEMS chip having an additional back chamber formed by the chamber cylinder, and a special purpose semiconductor (ASIC) chip for driving the MEMS chip, and having a conductive pattern for bonding to the case; Fixing means for fixing the case to the substrate; And an adhesive applied around the entire bonding surface of the case and the substrate fixed by the fixing means to bond the case and the substrate.

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

3 is a side cross-sectional view illustrating a silicon condenser microphone with an additional back chamber in accordance with the present invention.

According to the present invention, the silicon condenser microphone 100 having the additional bag chamber 152 has an additional bag on the PCB substrate 140 on which the connection terminals 142 and 144 and the conductive pattern 141 are formed, as shown in FIG. A chamber 150 for forming the chamber 152 and a special purpose semiconductor (ASIC) chip 120 for driving an electrical signal of the MEMS chip 110 are disposed and mounted, and then the MEMS is placed on the chamber 150. The chip 110 is attached, and the case 130 is attached to the PCB 140. The conductive pattern 141 and the ground connection terminal 144 are connected through the through hole 146.

The chamber cylinder 150 is to improve the sensitivity by increasing the insufficient back chamber space of the MEMS chip 110 itself, and to improve noise such as THD (Total Harmonic Distortion), and the upper surface of the chamber cylinder 150 includes the MEMS chip 110. Through holes 150a for connecting the back chamber 15 and the additional back chamber 152 formed by the < RTI ID = 0.0 >) < / RTI > are formed, and the MEMS chip 110 is placed on the silicon wafer 14 as shown in FIG. After the back plate 13 is formed using MEMS technology, the vibrating membrane 11 is formed with the spacer 12 therebetween. At this time, the shape of the chamber cylinder 150 may be a rectangular cylinder, a cylindrical shape, or the like, and the material may be a metal, a mold resin, or the like. In addition, although not shown in the drawing, the chamber barrel 150 is provided with electrical wiring for transmitting an electrical signal from the MEMS chip 110 to the special-purpose semiconductor chip 120.

The case 130 has a sound hole 130a for introducing external sound, and the method of attaching the case 130 to the PCB 140 is made of metal on the conductive pattern 141 formed on the PCB 140. After the case 130 is aligned, at least two or more spot welds are performed by laser welding or spot welding, and then the joints of the case 130 and the PCB 140 are sealed with an adhesive 164 such as epoxy. . Reference numeral 162 denotes a welding point.

Figure 4 is an embodiment showing an additional bag chamber structure of the rectangular cylinder according to the present invention, Figure 5 is an embodiment showing an additional bag chamber structure of the cylinder according to the present invention.

According to the present invention, the chamber cylinder 150 for forming an additional bag chamber may be a rectangular cylinder 150 'or a cylinder 150 ", as shown in FIGS. 4 and 5, and the rectangular cylinder 150 ') Or the cylinder 150 "is formed on the back chamber 15 to which the MEMS chip 110 is attached, and the through-hole 150a for forming a passage | pass.

The chamber 130 may be attached to the case 130 having various shapes on the PCB 140 on which the MEMS chip 110 having the additional back chamber 152 and the special purpose semiconductor chip 120 are mounted. Shaped silicon condenser microphone can be manufactured, but in the embodiment of the present invention, when the case shape is cylindrical 131 (first embodiment), in the case of square cylindrical type 132 (second embodiment), In the case of a cylindrical cylinder 1330 with wings (third embodiment), or in the case of a square cylinder 134 with wings at the end (fourth embodiment), a connecting terminal is formed on the mounting surface of the microphone, and the main portion of the electronic product In the case of being mounted on the PCB 300 (5th embodiment) and the like will be described.

[First Embodiment]

Figure 6 is an exploded perspective view of the first embodiment according to the present invention, the first embodiment of the present invention is a MEMS chip 110 having an additional back chamber 152 by a cylindrical cylinder 131, the chamber barrel 150 ) And the ASIC chip 120 is bonded to the PCB 140 on which the PCB is mounted by laser welding, and then the cylindrical case 131 is bonded to the PCB 140 by an adhesive 164. Here, the adhesive 164 may be a conductive epoxy, non-conductive epoxy, silver paste, silicone, urethane, acrylic, cream solder, or the like.

Referring to FIG. 6, the MEMS chip 110 and the ASIC chip 120 having the additional back chamber 152 are mounted on the PCB 140 by the chamber barrel 150, and are in contact with the cylindrical case 131. A circular conductive pattern 141 is formed at the portion to be formed. 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 140 is larger than that of the cylindrical case 131, a connection pad or a connection terminal for connecting to an external device can be freely disposed on a wide PCB substrate surface, and the conductive pattern 141 is a general PCB fabrication. After raising a copper foil through a process, it is formed by plating nickel (Ni) or gold (Au). In this case, various substrates such as a ceramic substrate, an FPCB, and a metal PCB may be used instead of the PCB 140.

The cylindrical case 131 is a PCB 140 and a connection surface is opened to mount chip components therein, and an acoustic hole 131a is formed on an upper surface thereof to allow external sound to flow therein. The cylindrical case 131 may be made of brass, copper, stainless steel, aluminum, nickel, or the like, and may be used by plating gold or silver.

After the cylindrical case 131 is aligned with the conductive pattern 141 of the PCB 140, the cylindrical case 131 is welded to the welding point 162, which is a part of the connection portion, using a laser processing machine (not shown). ) And the substrate 140 are first fixed, and then the adhesive 164 is applied around the entire surface of the joint to complete the microphone package. Here, the 'welding' is not welding the entire surface where the cylindrical case 131 and the PCB 140 meet, but at least one place (preferably two places to fix the case 131 and the PCB 140). Spot welding). In this way, the junction formed between the cylindrical case 131 and the PCB 140 by welding is called a welding point 162, and the cylindrical case 131 is fixed to the PCB 140 by the welding point 162. When the cylindrical case 131 is bonded to the PCB 140 with the adhesive 164 or the cylindrical case 131 does not move during the curing process, the bonding may be performed at the correct position. In addition, the conductive pattern 141 is connected through the ground terminal 144 and the through hole 146, and when the cylindrical case 131 is bonded thereto, it is easy to remove noise by blocking the inflow of external noise. have.

As shown in FIG. 6, the silicon condenser microphone of the present invention is bonded with an adhesive 164 after the conductive pattern 141 and the cylindrical case 131 of the PCB 140 are fixed by laser welding. The back chamber 15 of the MEMS chip 110 is extended to the additional back chamber 152 by a rectangular or cylindrical chamber cylinder 150 to improve sensitivity and improve noise such as THD (Total Harmonic Distortion). can do.

At least two or more connection terminals 142 and 144 for connecting to an external device may be formed on the bottom surface of the PCB 140, and each connection terminal 142 and 144 may be electrically connected to the chip component surface through a through hole. Can be. Particularly, in the embodiment of the present invention, when the connection terminals 142 and 144 are formed to the periphery of the PCB 140, the rework operation may be easily performed by approaching the electric iron through the exposed surface.

In the exemplary embodiment of the present invention, the fixing of the cylindrical case 131 to the PCB 140 has been described using laser welding as an example, but the cylindrical case 131 is fixed to the PCB 140 by another method such as soldering or punching. The adhesive 164 may be made of conductive or nonconductive epoxy, silver paste, silicone, urethane, acrylic, cream solder, or the like.

Second Embodiment

Figure 7 is an exploded perspective view of a second embodiment according to the present invention, the second embodiment of the present invention is fixed by welding a rectangular cylindrical case 132 to the PCB 140 with a laser and then bonded with an adhesive 164 to cure It is.

Referring to FIG. 7, the MEMS chip 110 and the ASIC chip 120 having the additional back chamber 152 are mounted on the PCB 140 by the chamber barrel 150. A rectangular conductive pattern 141 is formed at the contact portion. The conductive pattern 141 is formed of a copper foil film by a conventional PCB pattern technique.

The rectangular cylindrical case 132 has a rectangular cylindrical shape in which a surface connected to the PCB 140 is opened, and an acoustic hole 132a is formed in the upper surface thereof so that sound can be introduced into the rectangular cylindrical case 132.

After arranging the rectangular cylindrical case 132 to the conductive pattern 141 of the PCB 140, using a laser processing machine (not shown), as shown in FIG. A dot 162 is formed, and the adhesive 164 is applied to the entire circumference of the connection surface and cured to complete the packaging. Here, the conductive pattern 141 is connected to the ground terminal, and when the rectangular cylindrical case 132 is welded thereto, there is an advantage of easily removing noise by blocking the inflow of external noise.

The silicon microphone assembly thus packaged is the same as shown in Figure 6, so further description is omitted to avoid repetition.

Third Embodiment

8 is an exploded perspective view of a third embodiment according to the present invention. In the third embodiment of the present invention, a cylindrical case 133 having a wing 133c protruding in the shape of a “b” shape is formed on a PCB 140. ) And fixed by welding with a laser and then bonded with an adhesive (164) to cure.

Referring to FIG. 8, the MEMS chip 10 and the ASIC chip 20 having the additional back chamber 152 are mounted on the PCB 140 by the chamber barrel 150, and are in contact with the cylindrical case 133. A circular conductive pattern 141 is formed at the portion to be formed. Since the size of the PCB 140 is larger than that of the cylindrical case, a connection pad or connection terminal for connecting to an external device can be freely disposed on a wide PCB surface, and the conductive pattern 141 is formed of copper foil through a general PCB manufacturing process. After raising, it is preferable to plate nickel (Ni) or gold (Au). In the third embodiment of the present invention, the conductive pattern 141 may have a wider width than that of the first embodiment, corresponding to the wing 133c formed in the cylindrical case 133.

The case 133 of the third embodiment has a cylindrical shape in which the connection surface of the PCB 140 is opened, and an acoustic hole 133a is formed at an upper surface thereof so that sound can be introduced therein, and an end surface of the case body 133b is disposed outwardly. The protruding wing 133c is formed.

After aligning the tip blade 133c of the cylindrical case 133 to the conductive pattern 141 of the PCB, and then welding using a laser processor not shown to fix the cylindrical case 133 and the PCB 140 Bonding with adhesive 164 to complete packaging.

[Example 4]

9 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 has a rectangular cylindrical case 134 having a wing 134c protruding in a “b” shape at its end. ) Is fixed to the PCB 140 by welding with a laser and then bonded with an adhesive 164 to cure.

Referring to FIG. 9, the MEMS chip 110 and the ASIC chip 120 having the additional back chamber 152 are mounted on the PCB 140 by the chamber barrel 150. A rectangular conductive pattern 141 is formed at the contact portion. Since the size of the PCB 140 is larger than that of the rectangular cylindrical case 134, a connection pad or a connection terminal for connecting to an external device can be freely disposed on a wide PCB surface, and the conductive pattern 141 is a general PCB fabrication. It is preferable to plate nickel (Ni) or gold (Au) after raising copper foil through a process. In the fourth embodiment of the present invention, the conductive pattern 141 may be wider than that of the second embodiment, corresponding to the wing 134c formed at the end of the body 134b of the rectangular cylindrical case 134.

The rectangular cylindrical case 134 is a rectangular cylindrical shape in which the connection surface of the PCB 140 is opened, and an acoustic hole 134a is formed on the upper surface of the rectangular cylindrical case 134, and protrudes outward from an end surface of the case body 134b. Wing 134c is formed.

After aligning the end blades 134c of the case with the conductive pattern 141 of the PCB, and then welding with a laser processing machine (not shown) to fix the rectangular cylindrical case 134 and the PCB 140 and then to the adhesive 164. Glue to complete packaging.

[Example 5]

Fig. 10 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, the cylindrical or rectangular cylindrical case 130 is fixed to the substrate 140 wider than the case by welding, and then bonded with an adhesive 164, and the component surface of the PCB ( 140a), connection terminals 142 and 144 for connecting with the connection pad 320 of the main PCB 310 of the product in which the microphone is to be formed are formed. In the fifth embodiment of the present invention, four connection terminals are taken as an example, but this is only one example, and at least two or more eight may be formed, and reference numeral 162 denotes a welding point by welding. In addition, when the connection terminals 142 and 144 extend to the side wall portion of the substrate or to the opposite side of the component surface following the side wall portion, heat transfer such as an electric iron may be improved, thereby making it easier to rework.

In addition, the main PCB 310 of the product on which the silicon condenser microphone according to the fifth embodiment of the present invention is to be mounted has a circular or rectangular insertion hole 310a so that the case 130 of the silicon condenser microphone can be mounted. The connection pad 320 is formed to correspond to the connection terminals 142 and 144 formed on the substrate 140 of the microphone.

In the microphone of the fifth embodiment in which the silicon condenser microphone is mounted on the main PCB 310, as shown in FIG. 10, the case 130 protruding from the center portion of the substrate component surface 140a includes the main PCB 310. It is inserted into the insertion hole (310a) of the main PCB, the connection pad 320 and the connection terminals 142, 144 of the microphone is connected by the soldering (330).

Therefore, according to the mounting method of the present invention, the case 130 protruding over the substrate of the microphone is inserted into the insertion hole 310a formed in the main PCB 310, so that 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 case of the silicon condenser microphone, as shown in the cross-sectional view of FIG. 10, the MEMS chip 110 and the ASIC chip 120 having the additional back chamber 152 by the chamber barrel 150 are the PCB 140. The conductive pattern 141, which is mounted on the substrate and is in contact with the case 130, is formed.

  In this case, various substrates such as ceramic substrates, FPCBs, and metal PCBs may be used instead of the PCB 140, and the case 130 may include a sound hole 130a to allow sound to flow therein, and may include brass, copper, or stainless steel. It is made of stainless steel, aluminum, nickel alloy, etc. and can be used by plating with gold or silver.

As described above, the present invention has a chamber for forming an additional back chamber at the bottom of the MEMS chip to increase the insufficient back chamber space of the MEMS chip itself to improve sensitivity and reduce noise such as THD (Total Harmonic Distortion). There is an effect that can be improved.

In addition, by welding the case to the PCB with a laser and fixing it, then bonding it with an adhesive, the case is fixed when bonding, and no defects are generated.The bonding strength is strong, and the mechanical robustness is improved. There is an advantage that can be lowered.

Although the above has been described with reference to a preferred embodiment of the present invention, those skilled in the art will be able to variously modify and change the present invention without departing from the spirit and scope of the invention as set forth in the claims below. It will be appreciated.

Claims (8)

A case in which a sound hole is formed; A substrate having a chamber passage, an MEMS chip having an additional back chamber formed by the chamber cylinder, and a special purpose semiconductor (ASIC) chip for driving the MEMS chip, and having a conductive pattern for bonding to the case; Fixing means for fixing the case to the substrate; And And an adhesive applied around the entire bonding surface of the case and the substrate fixed by the fixing means to bond the case and the substrate. The method of claim 1, wherein the fixing means, A silicon condenser microphone having an additional back chamber, characterized in that it is a weld point formed by welding of a laser or soldering. The method of claim 1, wherein the adhesive A silicon condenser microphone with an additional back chamber, characterized in that it is any of conductive epoxy, non-conductive epoxy, silver paste, silicone, urethane, acrylic, cream solder. The method of claim 1, wherein the case A silicon condenser microphone having an additional back chamber, characterized in that it is cylindrical or square cylindrical. The method of claim 4, wherein the end of the case A silicon condenser microphone having an additional back chamber, characterized in that it is straight or curved outwardly to form a wing. The method of claim 1, wherein the chamber barrel A silicon condenser microphone having an additional back chamber, which is cylindrical or rectangular in shape, and has a through hole connected to the back chamber of the MEMS chip. The method of claim 1, wherein the substrate A silicon condenser microphone having an additional back chamber, which is any one of a PCB, a ceramic substrate, an FPCB substrate, and a metal PCB. The method of claim 1, wherein the substrate Silicon condenser microphone, characterized in that the connection terminal is formed on the surface on which the case is mounted to be connected to the external circuit.

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