JP2008141289A - Condenser microphone and manufacturing method therefor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method of manufacturing a condenser microphone capable of improving the adhesiveness between the core material of a casing substrate and a circuit board, and between the core material of the casing substrate and a top substrate, when bonding the circuit board and the top substrate to the front and the rear of the casing substrate with an adhesive, respectively, and to provide the condenser microphone. <P>SOLUTION: In the method of manufacturing the condenser microphone, a hole section 152 for a through hole is formed in a bonding region of a casing frame, and conductive patterns 24c, 24p are formed, on the front and rear of the casing frame including the inner surface of the hole section 152 and the bonding region. The hole section 152, positioned in the bonding region, is filled with an insulating synthetic resin, and the conductive pattern 24p in the bonding region is removed by etching. The top substrate and the circuit board are bonded and fixed to the bonding region, on the front and rear of the casing frame via an adhesive sheet. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a method for manufacturing a condenser microphone and a condenser microphone used in devices such as a mobile phone, a video camera, and a personal computer.

  A conventional condenser microphone has a structure in which components are housed in a cylindrical metal case such as a can-like aluminum having a sound hole, for example. For example, a circuit board is disposed as the lowest component in the metal case, and electrical components such as field effect transistors are mounted on the circuit board. A back electrode sandwiched between a pair of spacers is disposed on the circuit board, and a vibration film support frame having a vibration film such as a metal thin plate bonded to the lower surface is provided on the top. The lower end of the metal case is caulked and sealed to the lower surface of the circuit board. The metal case has a function of electromagnetic shielding of a condenser microphone. By the way, the condenser microphone as described above has a problem that the number of parts is large, the assembly productivity is low, and the manufacturing cost is increased.

  Thus, it has been proposed to manufacture a condenser microphone by the following method (Patent Document 1). In this manufacturing method, a large number of parts are integrated vertically and horizontally in a grid pattern for each of a circuit board on which electrical components such as field effect transistors are mounted, a back electrode board, a spacer, and a housing board for stretching a vibration film. A sheet-like collective member connected to is prepared, and these components are overlapped and joined together with the collective member. In the laminated member thus obtained, a large number of condenser microphones having a structure in which components are laminated are connected in a grid pattern. Then, by dicing this aggregate member with a cutter along the boundary line between each product region, each of the divided pieces can be obtained as a condenser microphone. As a result, a large number of products can be obtained at one time.

As another example of the condenser microphone manufactured in a laminated structure as described above, there is a type in which, for example, a top substrate and a circuit board on which electrical components are mounted are laminated on both upper and lower surfaces of a housing substrate. Thus, in the capacitor microphone having a laminated structure mainly composed of three layers of substrates (circuit substrate, housing substrate, and top substrate), the substrates are bonded to each other by an adhesive, and each substrate is electrically conductive. Through holes (via holes) are provided, and conduction of metal layers such as copper foil provided on the front and back surfaces of each substrate is ensured by the through holes.
JP 2002-345092 A

  However, in a capacitor microphone having a laminated structure mainly composed of three layers of substrates (circuit board, housing board, and top board) as described above, the circuit board and the top board are respectively mounted on the upper and lower surfaces of the housing board. When bonding, the adhesiveness of the adhesive to the metal layer is greatly inferior to the adhesiveness to the core material (for example, glass epoxy resin plate) of the substrate. This is because the surface of the metal layer has a smoothness better than that of the core material of the substrate, so that the adhesive strength of the adhesive is lowered.

  Further, when heat is applied to the condenser microphone as in reflow when the condenser microphone is mounted on the substrate, the coefficient of thermal expansion of the core material (for example, glass epoxy resin plate) of the housing substrate and the metal layer (for example, In terms of the coefficient of thermal expansion of the copper foil, the core material of the housing substrate is larger, so the core material pushes up the metal layer. In this case, when heat is applied, a force is applied in a direction in which the metal layers on the front and back surfaces of the casing substrate connected by through holes (via holes) are separated by the expansion internal pressure of the core material. For this reason, when the strength of the through hole is not sufficient, the metal layers on the front and back surfaces are cracked, and there is a possibility that conduction cannot be obtained.

  An object of the present invention is to provide a core material and a circuit board for a housing substrate, and a core material and a top substrate for a housing substrate when the circuit board and the top substrate are respectively bonded to the front and back surfaces of the housing substrate with an adhesive. It is an object of the present invention to provide a method of manufacturing a condenser microphone and a condenser microphone that can improve adhesiveness.

  In order to achieve the above object, according to the first aspect of the present invention, an adhesive region is provided on the front and back surfaces of the housing substrate having the first metal layer, and a top substrate and an electrical component are respectively provided to the adhesive region. In a method of manufacturing a capacitor microphone in which a circuit board to be mounted is bonded with an adhesive, a first step of forming a through hole for a through hole in the bonding region, an inner surface of the through hole, and the bonding region A second step of forming a second metal layer on the front and back surfaces of the housing substrate, a third step of filling the through hole located in the adhesion region with a filler, and first and second of the adhesion region. A capacitor comprising: a fourth step of removing the metal layer; and a fifth step of bonding and fixing the top substrate and the circuit substrate to the bonding regions on the front and back surfaces of the housing substrate through an adhesive. Microphone manufacturing Law is to summarized as.

  According to the first aspect of the present invention, when the circuit board and the top substrate are bonded to the front and back surfaces of the housing substrate with the adhesive, respectively, since there is no metal layer in the bonding region, The adhesion between the circuit board and the core material of the housing board and the top board is improved.

The invention of claim 2 is characterized in that, in claim 1, the filler is a resin filler that does not react with the etching solution used in the fourth step.
According to the second aspect of the present invention, the filler filled in the through hole is a resin filler that does not react with the etching solution used in the fourth step. That is, the front and back surfaces of the resin filler located in the adhesion region do not change. As a result, the amount of adhesive used during the bonding process performed in the fifth step is increased, or a gap is formed between the front and back surfaces of the resin filler and the applied adhesive when the adhesive is applied. It will not be adversely affected and will not adversely affect adhesion.

  According to a third aspect of the present invention, in the first or second aspect, the first step is performed with respect to the periphery of each part to be the housing substrate of the housing substrate assembly member having a plurality of parts to be the housing substrate. The through hole is formed leaving a part, and in the fifth step, each portion to be the top substrate of the top substrate assembly member having a plurality of portions to be the top substrate is formed on the housing substrate. Each of the parts to be the same circuit board of the circuit board assembly member having a plurality of parts to be the circuit boards is bonded and fixed to the bonding region on the surface of each part to be the circuit board by using an adhesive. It is characterized in that it is bonded and fixed to an adhesive region on the back surface of each part to be a substrate through an adhesive.

  According to the invention of claim 3, in the case of manufacturing a condenser microphone by laminating the housing substrate assembly member, the top substrate assembly member, and the circuit board assembly member, the effects of claim 1 and claim 2 are obtained. It can be easily realized.

According to a fourth aspect of the present invention, in the third aspect of the present invention, the method further includes a step of dicing the portion where the through hole is formed after the fifth step.
According to the invention of claim 4, in the case of manufacturing a condenser microphone by laminating the housing substrate assembly member, the top substrate assembly member, and the circuit board assembly member, the capacitor microphone separated from each assembly member is manufactured. In addition, the function and effect of the third aspect can be easily realized.

  The invention according to claim 5 is configured such that an adhesive region is provided on the front and back surfaces of the housing substrate having the metal layer, and the top substrate and the circuit board on which the electrical component is mounted are bonded to the adhesive region with an adhesive. In the condenser microphone, the top substrate and the circuit board on which the electrical components are mounted are bonded and fixed to the entire adhesion region on the front and back surfaces of the housing substrate with an adhesive without using the metal layer. The gist of the present invention is a condenser microphone.

  According to the fifth aspect of the present invention, when the circuit board and the top substrate are bonded to the front and back surfaces of the housing substrate with the adhesive, there is no metal layer in the bonding region. For this reason, the adhesiveness of the core material and circuit board of a housing substrate, and the core material and top substrate of a housing substrate improves.

  As described above, according to the present invention, when the circuit board and the top substrate are respectively bonded to the front and back surfaces of the housing substrate with the adhesive, the core material of the housing substrate, the circuit substrate, and the housing substrate There is an effect that the adhesion between the core material and the top substrate can be improved.

Embodiments of the present invention will be described below with reference to FIGS.
As shown in FIGS. 1 and 2, the housing 22 of the condenser microphone 21 of this embodiment includes a flat circuit board 23 as a mounting board, and a square frame-like housing base frame 24 as a housing board. A flat top substrate 25 as a top cover is laminated and fixed integrally with adhesive sheets 27A and 27B. The circuit board 23, the casing base frame 24, and the top board 25 are made of an electrical insulator made of resin such as epoxy resin. In this embodiment, although the said member is comprised by the glass cloth base material epoxy resin, it is not limited to an epoxy resin.

  As shown in FIG. 4A, conductive patterns 23a, 23b, and 23c made of copper foil as a conductive member are formed on the upper surface of the circuit board 23 (also referred to as the surface of the circuit board 23). In this specification, the upper surface means a surface facing upward when the circuit board 23 is placed downward, the casing base frame 24 is arranged in the middle, and the top board 25 is arranged upward, and the lower surface is the lower surface. The surface that faces In FIGS. 3 and 4A, the conductive patterns 23a, 23b, and 23c are indicated by hatching for convenience of explanation.

  As shown in FIG. 4A, the conductive pattern 23a has a first end located on the upper surface of the circuit board 23 near one end in the longitudinal direction and near one end on the short side. Two end portions 51 extend toward the center on the upper surface of the circuit board 23. The first end portion of the conductive pattern 23 a is a conduction portion 50.

  Here, on the upper surface of the circuit board 23, the axis in the short direction perpendicular to the central axis O (see FIG. 4A) penetrating in the thickness direction of the circuit board 23 is the x axis, and the axis in the longitudinal direction is This is called the y-axis.

  Then, on the upper surface of the circuit board 23, the conductive portion 50 having the x axis as the symmetry axis is centered on the central axis O and the region P1 that is line symmetric with respect to the conductive portion 50 and the line symmetry region P2 of the conduction portion 50 having the y axis as the symmetry axis. The point-symmetrical region P3 of the conduction part 50 as a point is included in a region where no conductive pattern is provided (hereinafter referred to as a non-conductive pattern region). The non-conductive pattern region is a region on the upper surface of the circuit board 23 that is surrounded by the conductive pattern 23c and excludes the conductive patterns 23a and 23b. In the present embodiment, a plurality of conductive patterns 23b (four in this embodiment) are provided.

  The conductive pattern 23 c is a ground conductive pattern, and is provided in a frame shape so as to face the frame shape of the housing base frame 24. The conductive patterns 23a and 23b are conductive patterns for connecting components, and are used for power supply input and value signal extraction.

  Further, as shown in FIGS. 3 and 4B, the surfaces including the regions P <b> 1 to P <b> 3 are covered with a resist 52 in a part of the upper surfaces of the conductive patterns 23 a to 23 c and the non-conductive pattern regions. For convenience of explanation, in FIG. 4B, the resist 52 is shown by hatching.

  The resist 52 is made of, for example, an epoxy resin as an insulating member, but is not limited to this material, and may be an insulating synthetic resin. The resist 52 is formed to have the same film thickness throughout the entire area (that is, the entire area including the regions P1 to P3) and has the same thickness as the conductive portion 50. That is, the portion of the resist 52 located in the regions P1 to P3 and the conductive portion 50 are set to have the same height (that is, thickness) with respect to the upper surface of the circuit board 23. The thickness of the conductive part 50 and the resist 52 is normally set to about 20 μm to 40 μm. In addition, the thickness of the conduction | electrical_connection part 50 and the resist 52 in this embodiment is set to 30 micrometers. In the resist 52, a notch 52 a is formed in the vicinity of the conductive portion 50 so that the conductive portion 50 is exposed. Further, in the resist 52, a window 52b is provided at a portion corresponding to the second end portion 51 of the conductive pattern 23a, one end portion of each conductive pattern 23b, and a part of the conductive pattern 23c. Is exposed through.

The frame-shaped peripheral portion of the conductive pattern 23 c is an exposed portion that is not covered with the resist 52 and is opposed to the housing base frame 24.
Further, as shown in FIG. 4C, a plurality of conductive patterns 23d and 23e made of copper foil are formed on the lower surface of the circuit board 23 (also referred to as the back surface of the circuit board 23). Only 23d is shown). In FIG. 4C, the conductive patterns 23d and 23e are hatched for convenience of explanation.

  The circuit board 23 is provided with a plurality of through holes 23g, and a conductive layer (not shown) is formed on the inner periphery of the through hole 23g. The conductive pattern 23c is connected to the conductive pattern 23d on the lower surface of the circuit board 23 through conductive layers of some through holes 23g among the plurality of through holes. A part of the conductive pattern 23d serves as a ground terminal.

  In addition, the conductive patterns 23a and 23b are connected to the signal output terminals (not shown) and the power supply input terminals (not shown) provided on the lower surface of the circuit board 23 through the conductive layers of the remaining through holes. The conductive pattern 23e is connected to the conductive pattern 23e.

  In the circuit board 23, an intermediate layer 23f made of copper foil is provided as shown in FIG. 1, and is electrically connected to the conductive pattern 23c and the through hole 23g that electrically connects the conductive pattern 23d. .

  On the circuit board 23, a field effect transistor 26 constituting an impedance conversion element as an electrical component provided in the housing 22 is mounted. The field effect transistor 26 is electrically connected to the second end portion 51 of the conductive pattern 23a and one end of several conductive patterns 23b among the plurality of conductive patterns 23b.

  The casing base frame 24 has openings at both upper and lower ends. As shown in FIG. 1, continuous conductive patterns 24a, 24b and 24c made of copper foil are formed on the upper and lower end surfaces and the side wall outer surface. Yes. As shown in FIGS. 2 and 5, the conductive patterns 24 a and 24 b are provided annularly with respect to the peripheral edges of the upper and lower openings of the housing base frame 24. 2 and 5, only the conductive pattern 24a is shown, but the conductive pattern 24b is also formed in the same shape as the conductive pattern 24a shown in FIGS.

  The conductive pattern 24c includes a metal such as copper on the inner surface of the recess 24i provided on the outer surface of the side wall of the housing base frame 24 except for the outer surfaces of the four corner portions C of the housing base frame 24. The conductive patterns 24a and 24b are electrically connected (see FIG. 1) by applying a conductive paste or applying a metal foil plating such as a copper foil plating. The conductive pattern 24c corresponds to a metal layer.

  In addition, a metal plating layer may be further formed on the conductive patterns 24a and 24b in the final stage of forming the conductive pattern and the through hole in the casing base frame 24. Accordingly, since the conductive patterns 24a and 24b protrude from the surface of the through hole filled with the resin, a gap into which the adhesive sheet 27A enters is increased, and the adhesive strength can be increased. The thickness of the conductive patterns 24a and 24b when a metal plating layer is further formed on the conductive patterns 24a and 24b is preferably about 25 μm to 40 μm.

  In FIG. 5, Q <b> 1 indicates a range of the conductive pattern 24 c provided in the recess 24 i of the housing base frame 24. As described above, the conductive pattern 24 c is provided in the recess 24 i provided on the outer side surface of the side wall of the housing base frame 24, so that electromagnetic shielding can be performed. A portion where the conductive pattern 24c is provided corresponds to an electromagnetic shield portion.

  Further, as shown in FIG. 5, a portion 154 a where the conductive pattern 24 c is not provided on the outer surface of the housing base frame 24 is provided in the corner portion C of the housing base frame 24. The part 154a where the conductive pattern 24c is not provided constitutes a part of the connecting part 154 shown in the manufacturing method described later, and the outer surface of the part 154a corresponds to a non-electromagnetic shield part. In FIG. 5, Q2 indicates the range of the non-electromagnetic shield part. The conductive pattern 24b on the lower surface side is connected to the conductive pattern 23d on the lower surface of the circuit board 23 via the conductive pattern 23c on the circuit board 23 as shown in FIG.

  The recess 24i is filled with an insulating synthetic resin such as an epoxy resin to form a filling portion 24j (see FIG. 1). The insulating synthetic resin such as the epoxy resin corresponds to a filler and a resin filler.

  In the housing base frame 24, substantially square frame-shaped adhesion regions SRa and SRb are formed by the upper and lower surfaces of the filling portion 24j and the upper and lower surfaces of the portion 154a where the conductive pattern 24c is not provided. In FIG. 5, only the adhesion region SRa provided on the upper surface of the casing base frame 24 is shown. The adhesion region is not limited to the rectangular frame shape, but may be another shape, and it may be any shape as long as it is similar to the frame shape of the housing base frame 24.

  As shown in FIGS. 1 and 2, the opening peripheral edge of the lower portion of the housing base frame 24, that is, the adhesion region SRb is an adhesive sheet 27A as a square-shaped adhesive disposed outside the conductive pattern 23c. Thus, the circuit board 23 is integrally bonded and fixed. The material of the adhesive sheet 27A is the same material as the resin filler used for the filling portion 24j. The electric component of the field effect transistor 26 on the circuit board 23 is accommodated in the housing base frame 24.

  The material of the adhesive sheet 27A may be the same as that of the resin material part used for the substrate of the housing base frame 24 of the adhesive sheet 27A. Accordingly, the same effect can be obtained if the adhesive sheet 27A, the circuit board 23, and the top board 25 are made of the same material as the resin material portion.

  As shown in FIG. 1, conductive patterns 25a and 25b made of copper foil or the like are formed on the upper and lower surfaces of the top substrate 25. The top substrate 25 is formed with a sound hole 28 for taking in sound from the outside.

  As shown in FIGS. 1 and 2, the peripheral edge of the opening at the top of the housing base frame 24, that is, the adhesive region SRa is an adhesive sheet 27 </ b> B serving as a square ring-shaped adhesive disposed outside the conductive pattern 24 a. Thus, the top substrate 25 is integrally bonded and fixed. The material of the adhesive sheet 27B is the same material as the resin filler used for the filling portion 24j. In this manner, the opening periphery of the upper portion of the casing base frame 24 is integrally connected to the top substrate 25 via the spacer 29 and the vibration film 30.

  As shown in FIGS. 1 and 2, an annular spacer 29 made of an insulating film is sandwiched and fixed between the housing base frame 24 and the top substrate 25. The spacer 29 is bonded to the conductive pattern 24a with a conductive adhesive. A vibration film 30 made of an insulating synthetic resin thin film such as a PPS (polyphenylene sulfide) film is stretched on the upper surface of the spacer 29 by adhesion, and a conductive film made of gold vapor deposition is formed on the lower surface of the vibration film 30. Layer 30a is formed.

  A through hole (not shown) is provided in the vibration film 30 and the spacer 29, and the conductive layer 30a includes a conductive paste filled in the through hole, the spacer 29 and the casing base frame 24 (more precisely, the spacer 29 and the conductive pattern 24a). ) Between the conductive pattern 24a through a conductive adhesive (not shown).

  As shown in FIG. 1, a plurality of through holes 36 are formed in the top substrate 25, and conductive patterns 25c continuous with the conductive patterns 25a and 25b are provided on the inner peripheral surfaces of the through holes 36. . The through hole 36 is filled with a conductive adhesive 37a, and a conductive portion 37 is formed by the conductive adhesive 37a and the conductive pattern 25c. The conductive portion 37 is electrically connected to the conductive layer 30a of the folded portion 30b (see FIG. 1) formed by folding the lower surface of the vibration film 30. Note that the conductive pattern 25c may be formed even if the conductive adhesive 37a in the through hole 36 is not filled, and if the conductive pattern 25c in the through hole 36 is not formed, the conductive adhesive 25a may be formed. It is also possible to only fill the agent 37a. In addition, electroconductivity and shielding property improve by forming both the conductive pattern 25c and the electroconductive adhesive agent 37a.

  The conductive patterns 25a and 25b of the top substrate 25 include a conductive portion 37, a conductive layer 30a, a conductive paste in a through hole (not shown) provided in the vibration film 30, and a conductive adhesive between the spacer 29 and the conductive pattern 24a. In addition, a conductive path to the ground terminal on the circuit board 23 is formed through the conductive patterns 24 a to 24 c on the housing base frame 24.

  In the housing base frame 24, a back plate 31 as an electrode plate is disposed opposite to the lower surface of the vibration film 30 with a spacer 29 interposed therebetween. The back plate 31 is configured by attaching a film 31b such as PTFE (polytetrafluoroethylene) to the upper surface of a back plate body 31a made of a stainless steel plate. The film 31b is subjected to polarization treatment by corona discharge or the like, and the film 31b constitutes an electret layer by this polarization treatment. In the present embodiment, the back plate 31 constitutes a back electrode, and the condenser microphone of this embodiment is constituted by a back electret type.

  Further, the back plate 31 is formed so as to have a substantially oval shape in a planar shape having an outer peripheral shape smaller than the inner peripheral shape of the housing base frame 24, and a gap P is formed between the inner and outer peripheral surfaces thereof. Is formed. A through hole 32 for allowing air movement due to vibration of the vibration film 30 is formed at the center of the back plate 31. The back plate 31 is formed by punching a stainless steel plate with a film 31b attached from the film 31b side, that is, from the upper side to the lower side in FIG. 2 with a punching blade (not shown).

  As shown in FIGS. 1 and 2, a holding member 33 made of a spring material is interposed between the back plate 31 and the circuit board 23 in the casing base frame 24 in a compressed state. The back plate 31 is pressed from the opposite side of the vibration film 30 in a direction in contact with the lower surface of the spacer 29 by the elastic force. As a result, a predetermined interval is maintained between the vibration film 30 and the back plate 31, and a capacitor portion that secures a predetermined capacity is formed between them.

  The holding member 33 is formed by stamping and forming a plate material obtained by performing gold plating on both the front and back surfaces of a stainless steel plate. The holding member 33 is substantially square-shaped frame portion 33a and obliquely toward the lower side from the four corners of the frame portion 33a. And four leg portions 33b projecting from each other. Accordingly, a space S is formed between the leg portions 33b below the frame portion 33a. In this embodiment, as shown in FIG. 1, the field effect transistor 26 on the circuit board 23 is disposed in the space S and between each pair of leg portions 33b.

  The upper surface of the frame portion 33a of the holding member 33 is formed with four contact portions 34 as spherical projections that come into contact with the lower surface of the back plate 31, and four lower end surfaces of the leg portions 33b. A contact portion 35 is formed as a spherical protrusion.

  Among each of the plurality of leg portions 33b, one leg portion 33b is brought into contact with the conducting portion 50 via the contact portion 35, and the remaining leg portions 33b are included in the non-conductive pattern region on the upper surface of the circuit board 23. The upper surface of the resist 52 located in the regions P <b> 1 to P <b> 3 is in contact via the contact portion 35.

  In the condenser microphone 21, when the sound wave from the sound source reaches the vibration film 30 through the sound hole 28 of the top substrate 25, the vibration film 30 is vibrated according to the frequency, amplitude, and waveform of the sound. As the vibration film 30 vibrates, the distance between the vibration film 30 and the back plate 31 changes from the set value, and the impedance of the capacitor portion changes. This change in impedance is converted into a voltage signal by the impedance conversion element and output.

(Production method)
Next, a method for manufacturing the condenser microphone 21 configured as described above will be described.

  The condenser microphone 21 is formed by stacking a plurality of sheet-like assembly members by stacking or the like and then dividing the assembly. In this manufacturing method, as shown in FIG. 6, a plurality of circuit board members 140, a casing base frame forming member 150, a vibration film forming member 200, a top cover forming member 250, a back plate 31, a holding member 33, and the like are used. The condenser microphone 21 is manufactured. The circuit board member 140 corresponds to a circuit board assembly member. The housing base frame forming member 150 corresponds to a housing substrate assembly member. The top cover forming member 250 corresponds to a top substrate assembly member.

  The circuit board member 140 is an insulating substrate as a collective member for forming a plurality of the circuit boards 23, and is formed in a sheet shape. A plurality of conductive patterns 23d and 23e are formed on the lower surface of the part to be the circuit board 23.

  The casing base frame forming member 150 is a plate material as an aggregate member for forming a plurality of casing base frames 24. Here, a method of forming the casing base frame forming member 150 will be described with reference to FIGS.

  First, in a double-sided board K (that is, a printed wiring board) having conductive patterns Ka and Kb as first metal layers made of copper foil of about 20 μm to 40 μm on the front and back surfaces of an insulating substrate Kc as a core material, Hole processing is performed between the parts to be the frame 24 and the peripheral edge of the double-sided substrate K by a router, a drill, or the like. Thereby, a plurality of hole portions 152 as through holes are formed in the double-sided substrate K at predetermined pitches in the vertical and horizontal directions (see FIG. 7A). The hole 152 is formed as a through hole (via hole), but after dicing described later, the hole 152 becomes a recess 24i of the housing base frame 24. The region where the hole 152 is formed is as follows. Except for the portion to be diced later, this is a region that becomes the adhesion regions SRa and SRb.

  In FIG. 6, for convenience of explanation, the filling portion 24j in the hole 152 is omitted and illustrated. By forming the hole portion 152, the portions to be the casing base frames 24 are connected to the adjacent portions through the connecting portion 154. In addition, the mutually adjacent site | part is the meaning containing the site | part used as the housing | casing base frame 24, and the peripheral part of the housing | casing base frame formation member 150. FIG.

  Next, as shown in FIG. 7B, the conductive pattern 24c is formed by applying a conductive paste on the inner surface of the hole 152 or by applying metal foil plating such as copper foil plating.

  In this case, the upper and lower surfaces of the portion that becomes the housing base frame 24 are regions that do not become the adhesion regions SRa and SRb (for example, include regions that become the conductive patterns 24a and 24b in the conductive patterns Ka and Kb of the double-sided substrate K). Applies a mask (not shown). This is because, for example, a new conductive pattern layer is not formed on the regions to be the conductive patterns 24a and 24b when the conductive pattern 24c is formed. When the conductive pattern 24c is formed, the conductive pattern 24c is formed on the portions of the conductive patterns Ka and Kb that are not masked, that is, part of the adhesion regions SRa and SRb. Simultaneously with the formation of, a conductive pattern 24p as a second metal layer as a metal layer is formed.

  Next, as shown in FIG. 7C, after the conductive pattern 24c is formed, the hole portion 152 is filled with an insulating synthetic resin such as an epoxy resin as a filler and a resin filler to form a filling portion 24j. Provide. Note that a material that does not react with an etchant described later is selected for the insulating synthetic resin such as an epoxy resin.

  Subsequently, as shown in FIG. 7 (d), the portions raised from the double-sided substrate K at both the upper and lower portions of the filling portion 24j are cut, and the upper and lower end surfaces of the filling portion 24j are made flat. At this time, the surfaces of the conductive patterns Ka and Kb are cut off. The thickness of the conductive patterns Ka and Kb is preferably about 10 μm to 25 μm.

  Next, as shown in FIG. 7E, the conductive patterns Ka and Kb on the connecting portion 154 are removed with an etching solution in a state where the mask is applied to the regions to be the conductive patterns 24a and 24b. As a result, the upper and lower surfaces of the connecting portion 154 to be the adhesion regions SRa and SRb and the upper and lower surfaces of the filling portion 24j are not provided with metal layers.

Thereafter, the mask is removed to expose regions to be conductive patterns 24a and 24b.
Next, the vibration film forming member 200 will be described.
The vibration film forming member 200 is a sheet material as a collective member in which island members 202 for forming a plurality of vibration films 30 are arranged vertically and horizontally. In addition, each island member 202 to be the vibration film 30 is connected to the vibration film forming member 200 via the connecting portion 204 with the frame member 206 and the adjacent island member 202, and at each corner of each island member 202, A folded portion 30b is formed. The spacer 29 is bonded to the lower surface of each island member 202. The top cover forming member 250 is a substrate as a collective member for forming a plurality of top substrates 25, and the sound holes 28 and the conductive patterns 25a and 25b are formed at predetermined pitches in the vertical and horizontal directions in the region where the top substrate 25 is to be formed. Has been.

  In order to manufacture the capacitor microphone 21, a conductive adhesive and an adhesive sheet are attached to the housing base frame forming member 150 in a state where the field effect transistor 26 is mounted on the circuit board member 140 in advance. Both are integrated by bonding with 27A. In FIG. 6, only a part of the adhesive sheet 27 </ b> A is shown for convenience of explanation, but the adhesive sheet 27 </ b> A is used for each part to be the circuit board 23.

  Next, the holding member 33 and the back plate 31 are housed in a portion corresponding to the housing base frame 24 with respect to the assembled assembly. Next, the vibration film forming member 200 is bonded to the assembly using a conductive adhesive and an adhesive sheet 27B. At this time, the conductive pattern 24 a corresponding to the housing base frame 24 and the spacer 29 of the island member 202 are bonded by the conductive adhesive. In FIG. 6, for convenience of explanation, only a part of the adhesive sheet 27 </ b> B is illustrated, but the adhesive sheet 27 </ b> B is used for each part to be the casing base frame 24.

  Thereafter, the top cover forming member 250 is bonded to the assembly on which the vibration film forming member 200 is laminated using a conductive adhesive. At this time, each conductive pattern 25b of the top cover forming member 250 and the vibration film 30 are bonded with the adhesive. Thereafter, dicing (cutting) is performed using a diamond blade or the like to form a plurality of condenser microphones 21.

  FIG. 6 shows a state where 2 × 2 = 4 condenser microphones 21 are formed for convenience of explanation, but in reality, several hundred condenser microphones 21 are formed at a time.

The method for manufacturing the condenser microphone 21 of the present embodiment has the following characteristics.
(1) In the method for manufacturing the condenser microphone 21 of the present embodiment, through holes 152 (through holes) are formed in the adhesion regions SRa and SRb of the housing base frame 24 (housing substrate) (first step). ), Conductive patterns 24c and 24p (second metal layer) are formed on the inner surface of the hole 152 and the front and back surfaces of the housing base frame 24 including the adhesion regions SRa and SRb (second step). The holes 152 located in the adhesion regions SRa and SRb are filled with an insulating synthetic resin such as an epoxy resin as a filler (third step), and the conductive patterns Ka and Kb (first step) of the adhesion regions SRa and SRb are filled. The first metal layer) and the conductive pattern 24p (second metal layer) were removed by cutting or etching (fourth step). Then, the top substrate 25 and the circuit board 23 are bonded and fixed to the bonding regions SRa and SRb on the front and back surfaces of the casing base frame 24 (the casing substrate) via the adhesive sheets 27A and 27B (adhesive). (5th process).

  As a result, according to the present embodiment, when the circuit board 23 and the top board 25 are bonded to the front and back surfaces of the casing base frame 24 by the adhesive sheets 27A and 27B, respectively, the metal is not added to all the bonding regions SRa and SRb. Since there is no layer, the adhesion between the insulating substrate Kc (core material) of the housing base frame 24 and the circuit board 23 and the insulating substrate Kc of the housing base frame 24 and the top substrate 25 can be improved.

  (2) In the method for manufacturing a condenser microphone according to the present embodiment, an insulating synthetic resin such as an epoxy resin as a filler that fills the hole 152 is a resin filler that does not react with the etching solution used in the fourth step. It is said. Therefore, in the etching process of the fourth step, the front and back surfaces of the insulating synthetic resin such as epoxy resin located in the hole 152, that is, in the adhesion regions SRa and SRb are not changed. As a result, the amount of adhesive used during the bonding process performed in the fifth step is increased, or a gap is formed between the front and back surfaces of the resin filler and the applied adhesive when the adhesive is applied. There is no such thing, and there is no adverse effect on adhesion.

  (3) In the first step of the method for manufacturing the condenser microphone of the present embodiment, a housing base frame forming member 150 (housing substrate assembly member) having a plurality of parts to be the housing base frame 24 (housing substrate). A hole 152 (through hole) is formed with a part remaining around the portion to be the casing base frame 24. Further, in the fifth step, the respective parts to be the top substrate of the top cover forming member 250 (top substrate assembly member) are respectively attached to the adhesive regions SRa on the surface of the respective parts to be the casing base frame 24 with the adhesive sheets 27A ( The adhesive was fixed via an adhesive). In addition, each part to be the circuit board 23 of the circuit board member 140 (circuit board assembly member) is attached to the adhesive region SRb on the back surface of each part to be the casing base frame 24 via an adhesive sheet 27B (adhesive). Adhesion was fixed. As a result, the capacitor base microphone forming member 150 (casing substrate assembly member), the top cover forming member 250 (top substrate assembly member), and the circuit board member 140 (circuit substrate assembly member) are laminated to produce a capacitor microphone. In this case, the effects (1) and (2) can be easily realized.

  (4) In the method for manufacturing the condenser microphone according to the present embodiment, the portion where the hole 152 is formed is diced after the fifth step. As a result, according to the present embodiment, when the condenser microphone is manufactured by stacking the casing base frame forming member 150, the top cover forming member 250, and the circuit board member 140, the condenser microphone separated from each assembly member In the case of manufacturing, the effect of claim 3 can be easily realized.

  (5) The condenser microphone of the present embodiment has adhesive regions SRa and SRb on the front and back surfaces of the housing base frame 24, and is a top substrate for all the adhesive regions SRa and SRb on the front and back surfaces of the housing base frame 24, respectively. 25 and the circuit board 23 on which the electrical components are mounted are bonded by an adhesive without using a metal layer. As a result, the adhesion between the insulating substrate Kc (core material) of the housing base frame 24 and the circuit board 23 and the insulating substrate Kc (core material) of the housing base frame 24 and the top substrate 25 is improved.

  In addition, since the upper and lower surfaces of the filling portion 24j located in the bonding regions SRa and SRb, the top substrate 25 and the circuit board 23, and the filling portion 24j are made of the same material as the adhesive, the adhesiveness is not impaired.

In addition, this embodiment can also be changed and embodied as follows.
In the above embodiment, the back plate main body 31a is made of a stainless steel plate, but may be made of a brass plate or a titanium plate.

The present invention may be embodied in a method of manufacturing a foil electret type condenser microphone in which the vibration film 30 is made of a polymer film for electrets.
The present invention may be embodied in a method for manufacturing a charge pump type capacitor microphone having a booster circuit. In the case of such a configuration, electrodes facing each other are provided on the vibration film 30 and the back plate 31 in place of the electret layer.

  In the above embodiment, the back electret type electret condenser microphone has been described. However, the present invention may be applied to a front electret type electret condenser microphone.

  The impedance conversion element mounted on the circuit board 23 of the above embodiment is an example, and any analog / digital operation method may be used as long as it is a known one that can detect a change in capacitance. Applicable.

  In the embodiment, the conductive patterns Ka and Kb (first metal layer) and the conductive pattern 24p (second metal layer) in the adhesion regions SRa and SRb are removed by cutting and etching (fourth process). ) Is not limited to this method. The removal of the conductive patterns Ka and Kb (first metal layer) and the conductive pattern 24p may be performed only by etching with an etching solution, or may be performed only by cutting.

Sectional drawing which shows the condenser microphone of one Embodiment of this invention. The disassembled perspective view of the condenser microphone of FIG. Explanatory drawing which shows the positional relationship of the conductive pattern on the circuit board 23 surface, and a resist. (A) is a top view of the conductive pattern on the circuit board 23 surface, (b) is a plan view of the conductive pattern, and (c) is a plan view of the conductive pattern on the back surface of the circuit board 23. The top view of the housing | casing base frame 24. FIG. The perspective view which shows each member used for manufacture of a condenser microphone. (A)-(e) is explanatory drawing which shows the hole 152 of a condenser microphone, and the formation process of its periphery.

Explanation of symbols

21 ... Condenser microphone, 23 ... Circuit board,
24 ... Housing base frame (housing substrate), 24c ... Conductive pattern,
24p ... conductive pattern (second metal layer),
25 ... Top substrate, 27A, 27B ... Adhesive sheet (adhesive),
152 ... hole (through hole), Ka, Kb ... conductive pattern (first metal layer),
SRa, SRb: Adhering region.

Claims (5)

An adhesive microphone is provided in which a bonding region is provided on the front and back surfaces of a housing substrate having a first metal layer, and a top substrate and a circuit board on which an electrical component is mounted are bonded to the bonding region with an adhesive. In the manufacturing method,
A first step of forming a through hole for a through hole in the adhesive region;
A second step of forming a second metal layer on the front and back surfaces of the housing substrate including the inner surface of the through hole and the adhesion region;
A third step of filling the through hole located in the adhesion region with a filler;
A fourth step of removing the first and second metal layers in the adhesion region;
A method of manufacturing a condenser microphone, comprising: a fifth step of bonding and fixing the top substrate and the circuit substrate to an adhesive region on the front and back surfaces of the housing substrate through an adhesive.   The method for manufacturing a condenser microphone according to claim 1, wherein the filler is a resin filler that does not react with the etching solution used in the fourth step. The first step is to form the through hole leaving a part of the periphery of each portion to be the housing substrate of the housing substrate assembly member having a plurality of portions to be the housing substrate,
In the fifth step, each of the parts of the top substrate assembly member having a plurality of parts to be the top substrate is attached to the adhesive region on the surface of each part to be the housing substrate. And adhesively fix each part to be the same circuit board of the circuit board assembly member having a plurality of parts to be the circuit board to an adhesive region on the back surface of each part to be the housing substrate. 3. The method of manufacturing a condenser microphone according to claim 1, wherein the condenser microphone is bonded and fixed.   4. The method of manufacturing a condenser microphone according to claim 3, further comprising a step of dicing the portion where the through hole is formed after the fifth step. In a condenser microphone configured by providing an adhesive region on the front and back surfaces of a housing substrate having a metal layer, and a top substrate and a circuit board on which electrical components are mounted respectively bonded to the adhesive region with an adhesive,
A top substrate and a circuit board on which an electrical component is mounted are bonded and fixed to each other on the front and back surfaces of the housing substrate with an adhesive without using the metal layer. Condenser microphone.

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