JP2006129255A - Circuit module - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a circuit module which is reduced in size. <P>SOLUTION: An imaging device 16 and peripheral components are packaged on a surface of a wiring board 12 including multilayered wiring, and a lens mount 13 is provided so as to position a lens 18 above the imaging device 16. A circuit element 14 such as a DSP and a connection means 15 are packaged on a rear face of the wiring board 12, wherein the connection means 15 is a solder ball with a core and a space 22 is formed, because of existence of the core, between wiring boards 12 in the case of packaging. The circuit element 14 is positioned in this space 22. Therefore, the circuit module can be connected with a mounting substrate by reflow and the circuit module that is reduced in size, is provided. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a circuit module, and more particularly to a circuit module that achieves miniaturization.

  In recent years, circuit modules have been actively adopted in mobile phones, portable computers and the like. Accordingly, circuit modules and the like are required to be reduced in size, thickness, and weight. In the present invention, as an example, a description will be given using a circuit module using a CCD as an image sensor. The same applies when an image sensor other than a CCD (for example, a CMOS sensor or the like) is used.

  With reference to FIG. 9A, the structure of a conventional circuit module 100 will be described. First, the CCD 102 is mounted on the mounting substrate 101. A lens 105 that collects light from the outside is fixed to the lens barrel 106 above the CCD 102. The lens barrel 106 is held by a lens mount 107, and the lens mount 107 is mounted on the mounting substrate 101 by a lens fixing screw 108. Further, the flexible substrate 120 is fixed to the mounting substrate 101 via the connecting means 121.

  Here, the CCD is an abbreviation for (Charge Coupled Device), and has a function of outputting charges corresponding to the intensity of light collected by the lens 105. The lens barrel 106 has a screw-like side surface (not shown), and has a function of focusing the lens 105 by rotating.

  Further, the chip component 103 and the back surface chip component 104 are mounted on the front surface and the back surface of the mounting substrate 101. These chip parts include a DSP, a drive IC, a capacitor, a resistor, and a diode. The DSP is an abbreviation of (Digital Signal Processor) and has a function of processing a digital signal sent from the CCD 102 at high speed. Further, the drive IC has a function of boosting a drive signal from the DSP to drive the CCD 102 and transferring charges accumulated in the CCD 102.

Referring to FIG. 9B, the flexible sheet 120 is electrically connected to the mounting substrate 101 via connection means 121 such as solder provided in the peripheral portion of the mounting substrate 101. A connector (not shown) is exposed at the other end of the flexible sheet, and the circuit module 100 is electrically connected to the outside via this connector (see Patent Document 1). .
JP 2002-182270 A

  However, the circuit module as described above has the following problems.

  Since elements such as a DSP and a driver IC for performing signal processing and driving of the CCD 102 are mounted on the surface of the mounting substrate 101, the mounting substrate 101 having a large area is required, which hinders downsizing of the circuit module. Was.

  The present invention has been made in view of such problems, and a main object of the present invention is to provide a circuit module that is miniaturized.

  A circuit module according to the present invention includes a wiring board that is formed in multiple layers via an insulating layer and has conductive paths on both sides, a first circuit element that is electrically connected to the surface of the wiring board, and the wiring board A second circuit element electrically connected to the back surface; and a connecting means, wherein the second circuit element is positioned in a space formed by disposing the connecting means on the wiring board. And

  In addition, the circuit module of the present invention includes a wiring board that is formed in multiple layers via an insulating layer and has conductive paths on both sides, an image sensor that is electrically connected to the surface of the wiring board, and the wiring board. A lens mount that is provided and fixes a lens above the image sensor; and a circuit element and a connection means that are electrically connected to the back surface of the wiring board; and the connection means is disposed on the wiring board. The circuit element is positioned in a space formed by the above.

  In addition, the circuit module of the present invention includes a wiring board that is formed in multiple layers via an insulating layer and has conductive paths on both sides, an image sensor that is electrically connected to the surface of the wiring board, and the wiring board. A part of the conductive path formed on the back surface of the wiring board, provided with a lens mount for fixing the lens above the imaging device and a circuit element electrically connected to the back surface of the wiring board; Is an electrode for electrically connecting to the protruding electrode provided on the mounting substrate side.

  Furthermore, the circuit module according to the present invention includes a wiring board formed in multiple layers with an insulating layer therebetween and having conductive paths on both sides, an imaging device and a circuit element electrically connected to the surface of the wiring board, and the wiring A lens mount that is provided on a substrate and fixes a lens above the image sensor; the lens mount is supported by a support; and the wiring substrate and the lens mount are connected around the image sensor A light shielding wall is provided, and the circuit element is disposed at a peripheral end portion of the wiring board.

  According to the circuit module of the present invention, the circuit element is positioned in the space formed by arranging the connecting means on the wiring board. Therefore, since circuit elements can be mounted at locations that cannot be mounted conventionally, it is possible to reduce the size of a circuit module that can be reflow mounted.

  According to the circuit module of the present invention, a part of the conductive path formed on the back surface of the wiring board is an electrode for electrically connecting with the protruding electrode provided on the mounting board side. Therefore, a circuit module that can be connected to the mounting substrate using a socket or the like and can be easily replaced or mounted can be realized.

  Furthermore, according to the circuit module of the present invention, the lens mount is supported by the support, and the image sensor is shielded by the light shielding resin. Accordingly, since the contact area between the lens mount and the wiring board can be minimized, the area for mounting the circuit elements increases. As a result, circuit elements can be arranged on the mounting substrate with high density, and the circuit module can be downsized.

  With reference to FIG. 1 and FIG. 2, the circuit module 10A of this embodiment which is a camera module is demonstrated.

  Referring to FIG. 1A, a circuit module 10A is provided with a lens mount 13 on the surface of a wiring board 12 having conductive paths on both sides, and a circuit element 14 and connecting means 15 on the back side. ing. An imaging element 16 is built in the lens mount 13, and a lens 18 is provided above the lens mount 13. Here, as shown in FIG. 1B, the circuit element 14 is located in the space formed by the connecting means 15. A peripheral component 17 is provided around the image sensor 16. The components of these circuit modules 10A will be described below.

  The wiring board 12 is a multilayer wiring board in which wiring layers are stacked with an insulating layer interposed therebetween, and is thin and does not have a base material in the center. Conductive paths such as electrodes and bonding pads are exposed on the front and back surfaces. In the present embodiment, a four-layer multilayer wiring board is illustrated, but the present invention is not limited to this, and the number of wiring layers may be increased or decreased according to the specifications of the circuit module. The details of the wiring board 12 will be described later.

  The image sensor 16 is a CCD, is fixed to the surface of the wiring board 12, and is positioned below the lens 18. The image pickup device 16 has a function of converting the light collected by the lens 18 into an electric signal, and outputs an electric charge according to the amount of incoming light. In this embodiment, it is mounted face down, but it may be mounted face up using a thin metal wire. In the present invention, the case where a CCD is used as the image sensor 16 will be described. However, the same effect can be obtained by using a CMOS sensor as the image sensor 16.

  The lens mount 13 is mounted on the surface of the wiring board 12 via an insulating adhesive. The imaging element 16 and the peripheral component 17 mounted on the surface of the wiring board 12 are covered with the lens mount 13. The lens mount 13 has a hollow structure, and a hole for allowing the light collected by the lens 18 to pass therethrough is provided near the center of the upper surface. The lens mount 13 is made of a light shielding material.

  The lens 18 is fixed to a lens barrel 19 provided on the upper portion of the lens mount 13 with an adhesive. The planar position of the lens 18 exactly matches the planar position of the image sensor 16 located below the lens 18. Accordingly, the light incident on the lens 18 is accurately condensed on the light receiving portion of the image sensor 16. Further, if the lens barrel 19 and the lens mount 13 are connected by a screw structure, both can be coupled while adjusting the focal point of the lens 18.

  The circuit element 14 is mounted on the back surface of the wiring board 12 and is a chip set such as a DSP and a driver IC for processing and driving an electric signal obtained from the imaging element 16. When the image sensor 16 is a CMOS sensor, the circuit element 14 can be configured by an LSI to which an image processing function (compatible with MPEG4), an interface (USB 2.0 I / F), and the like are added. Also, peripheral components may be fixed to the back surface of the wiring board 12. The circuit element 14 and the image sensor 16 are electrically connected via the wiring board 12. The circuit element 14 is fixed so as to be located in the space 22 formed by the connecting means 15.

  The connection means 15 is provided for exchanging electrical signals with the outside. In this embodiment, the connecting means 15 is a spherical particle, and a conductor 24 made of a conductive metal layer and a solder layer is deposited around a core 23 made of a resin. By using this resin core solder ball as the connection means 15, when the circuit module 10 </ b> A is fixed to the mounting substrate 20, the core 23 is not crushed beyond the particle size. The space 22 can be formed. By forming the space 22, the circuit element 14 and the peripheral component 17 can be mounted on the back surface of the wiring board 12, and the circuit module can be downsized. Further, the circuit module 10 </ b> A can be reflow mounted while mounting components on the back surface of the wiring board 12.

  The peripheral component 17 is mainly a chip component such as a chip capacitor, a resistor, and a coil that are noise countermeasure components, and is electrically connected to the wiring board via a brazing material such as solder.

  The back surface structure of the circuit module 10A will be described with reference to FIG. 2A is a back view of the circuit module 10A, FIG. 2B is a diagram showing a flexible sheet for fixing the circuit module 10A, and FIG. 2C is a diagram illustrating the circuit module 10A as a flexible sheet. It is a perspective view at the time of mounting.

  Referring to FIG. 2A, the circuit element 14 and the peripheral component 17 are freely mounted in the area A1, but the connection means 15 is provided at the corner except for the vicinity of the center of the wiring board 12 (area A1). It is provided to gather. Therefore, as shown in FIG. 2B, the wiring can be extended to a region corresponding to the region A in the flexible sheet 26. Further, in the single-layer flexible sheet, the wiring can be passed through a region corresponding to the vicinity of the center of the side edge of the wiring substrate 12, so that the wiring 27 extending from the electrode 26 can be drawn out in one direction. Therefore, as shown in FIG. 2C, the area of the flexible sheet 26 to be used can be minimized.

  In the present embodiment, the connection means 15 is arranged at the four corners to improve the stability of the wiring board 12.

  With reference to FIG. 3, the circuit module 10B of another form is demonstrated. Here, it demonstrates centering on difference with the circuit module 10A mentioned above.

  The circuit module 10B has a configuration in which the connection means 15 of the circuit module 10A described above is removed, and a part of the conductive path formed on the back surface of the wiring board is electrically connected to the protruding electrode 33 provided on the mounting board side. It is the electrode 35 for connecting to.

  As a mounting method of the circuit module 10B, referring to FIG. 3A, a socket 30 and a protruding electrode 33 are provided on the mounting substrate 20, and a material having elasticity such as a spring is provided inside the protruding electrode 33. Is stored, and the upward force is always working. As a result, the circuit module 10 </ b> B is housed in the socket 30, whereby the electrode 35 and the protruding electrode 33 are electrically connected.

  Referring to FIG. 3B, the circuit module 10B is fixed by the upward force of the protruding electrode 33 and the pressing portion 34 formed at the end of the socket 30, and the electrode 35 and the protruding electrode 33 are Stable and electrically connected. By adopting such a form, the circuit module can be easily mounted or replaced.

  With reference to FIG. 4, a circuit module 10C of another form will be described. Here, the description will focus on differences from the circuit module 10A described above.

  In this embodiment, the lens mount 13 is supported by the support body 38, and the peripheral component 17 can be disposed at the peripheral end portion of the wiring board 12, thereby reducing the size of the circuit module.

  Specifically, the side wall of the lens mount 13 is removed, and the peripheral component 17 is mounted on the side wall adhesion region A2. In addition, a light shielding wall 36 is formed to prevent light from other than the lens 18 from entering the image pickup device 16 with the removal of the side wall. The light shielding wall 36 is made of a light shielding resin and is provided so as to surround the image sensor 16. The lens mount 13 is fixed by an adhesive, and the wiring substrate 12 is fixed by an underfill resin 37.

  Referring to FIG. 4C, side wall thickness T1 needs to support lens 18 and lens barrel 19, and has a thickness of about 0.4 mm to 0.5 mm so as to have a predetermined strength. ing. However, since the role of the light shielding wall 36 is only to block the light incident on the imaging device 16, the thickness T2 is about 0.2 mm to 0.3 mm. Therefore, by removing the side wall and forming the light shielding wall 36, it is possible to increase the mountable area of peripheral components on the wiring board 12, and the circuit module can be reduced in size.

  A method for manufacturing the circuit module 10A will be described with reference to FIGS.

  Referring to FIG. 5A, a laminated sheet 40 in which first and second conductive films 42A and 42B are in close contact with both surfaces of an insulating film 41 is prepared. As the material of the insulating film 41, either a thermoplastic resin or a thermosetting resin is selected. In consideration of thermal conductivity and the like, an inorganic filler may be mixed into the resin. Moreover, in order to improve the whole intensity | strength, the insulating film 41 may include a glass cloth, and the glass cloth may be mixed with an inorganic filler. The film thickness of the insulating film 41 can be about 50 μm.

  As the material of the first and second conductive films 42A and 42B, metals having copper as a main material can be generally used. In this embodiment, the rolled copper foil is employed as the material for the first and second conductive films 42A and 42B. The thickness of both conductive foils may be about 10 μm. Further, both the conductive films may be directly coated on the insulating film 41 by a plating method, a vapor deposition method or a sputtering method, or a metal foil formed by a rolling method or a plating method may be attached.

  The surface of the insulating film 41 is exposed by partially removing the second conductive film 42B. Then, the through hole 45 is formed by removing the insulating film 41 using the second conductive film 42B as a mask. The insulating film 41 can be removed using a laser. This removal by laser is performed until the surface of the first conductive film 42 </ b> A is exposed at the bottom of the through hole 45. As the laser used here, a carbon dioxide laser is preferable. If there is a residue at the bottom of the through hole 45, wet etching is performed with sodium permanganate or ammonium persulfate to remove this residue.

  Referring to FIG. 5B, the connecting portion 21 that electrically connects the first conductive film 42A and the second conductive film 42B is formed by performing a plating process. More specifically, the connection portion 21 is formed by forming a plating film on the entire surface of the second conductive film 42 </ b> B including the through hole 45.

  This plating film is formed by both electroless plating and electrolytic plating, and about 2 μm of Cu is formed on the entire surface of the second conductive film 42B including at least the through holes 45 by electroless plating. As a result, the first conductive film 42A and the second conductive film 42B are electrically connected. Therefore, electrolytic plating is performed again using both the conductive films as electrodes, and Cu of about 20 μm is plated. Thereby, the through-hole 45 is embedded with Cu, and the connection part 21 is formed. If filling plating is performed, only the through holes 15 can be selectively embedded.

  Referring to FIG. 5C, the second conductive film 42B is etched to form a wiring layer. Then, a conductive film is stacked via an insulating layer, and the above-described steps are repeated, whereby the wiring substrate 12 having a multilayer wiring is formed. Here, the upper wiring layer is referred to as a first wiring layer 47, and the lower wiring layer is referred to as a second wiring layer 48. In this embodiment, the wiring board 12 having four wiring layers is formed. However, the number of wiring layers may be increased or decreased depending on the specifications of the circuit module.

  Referring to FIG. 6A, circuit element 14 and connecting means 15 are mounted on second wiring layer 48 formed on the lower surface of wiring board 12. In addition, it is possible to mount peripheral components around the circuit element 14. Here, the circuit element 14 is an image processing element such as a DSP or a driver IC.

  With reference to FIG. 6B, the image sensor 16 and the peripheral component 17 are mounted on the first wiring layer 47. In this embodiment, the CSP package is mounted by reflowing, but it is also possible to mount a bare chip by wire bonding.

  Referring to FIG. 6C, the lens mount 13 is placed on the upper surface of the first wiring layer. At this time, at least the image sensor 16 is covered with the lens mount 13, and the lens 18 is placed so as to be positioned on the upper surface of the image sensor 16.

  The circuit module 10A is completed as described above.

  Next, a method for manufacturing the circuit module 10C will be described with reference to FIG. Here, since the manufacturing method of the distribution board 12 is the same as the manufacturing method mentioned above, it omits.

  7A and 7B, after mounting the circuit element 14 and the connection means 15 on the second wiring layer 48, the imaging element 16 and the peripheral component 17 are mounted on the first wiring layer 47. Implement. At this time, the underfill resin 37 is filled so as to surround the back surface of the image sensor 16 and the wiring substrate 12 and the periphery of the image sensor 16.

  With reference to FIG. 7C, the light shielding wall 36 and the lens mount 13 are fixed to the upper surface of the wiring board 12. The light shielding wall 36 is formed so as to surround the periphery of the image sensor 16, is fixed to the lens mount 13 via an adhesive, and is fixed to the wiring board 12 via an underfill resin 37. Therefore, the light shielding wall 36 is attached before the underfill resin 37 is cured. In this way, the circuit module 10C is manufactured.

  With reference to FIG. 8, a circuit module 10D of another form will be described. Here, it demonstrates centering on difference with the circuit module 10A mentioned above. Specifically, the first circuit element 51 and the chip component 53 are placed on the upper surface of the wiring board 12 and sealed with a sealing resin 54. The second circuit element 52 and the connecting means 15 are placed on the back surface, and the second circuit element is arranged in the space 22 formed by the connecting means 15. By mounting the second circuit element on the back surface of the wiring board 12, the circuit module can be reduced in size in a plane.

  Here, the circuit element is surface-mounted, but it is also possible to mount it using a thin metal wire. Furthermore, the chip component 53 can be mounted on the back surface of the wiring board.

In this embodiment, a circuit module in which circuit components are mounted only on the back surface of the wiring board 12 can be formed.

1A and 1B are a perspective view and a cross-sectional view illustrating a circuit module of the present invention. FIG. 2 is a plan view (A), a plan view (B), and a perspective view (C) illustrating a circuit module of the present invention. 1A and 1B are a cross-sectional view and a cross-sectional view illustrating a circuit module of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view (A), a sectional view (B), and a plan view (C) illustrating a circuit module of the present invention. It is sectional drawing (A)-sectional drawing (C) explaining the manufacturing method of the circuit module of this invention. It is sectional drawing (A)-sectional drawing (C) explaining the manufacturing method of the circuit module of this invention. It is sectional drawing (A)-sectional drawing (C) explaining the manufacturing method of the circuit module of this invention. It is a top view explaining the circuit module of this invention. It is sectional drawing (A) and a top view (B) explaining the conventional circuit module.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10A-D Circuit module 12 Wiring board 13 Lens mount 14 Circuit element 15 Connection means 16 Imaging element 17 Peripheral component 18 Lens 19 Lens barrel 20 Mounting board 21 Connection part 22 Space 23 Core 24 Conductor 25 Flexible sheet 26 Electrode 27 Wiring 32 Board Side electrode 33 Projecting electrode 34 Holding part 35 Electrode 36 Light shielding wall 37 Underfill resin 38 Support 40 Laminated sheet A1 area A2 Side wall adhesion area

Claims (11)

A wiring board formed in multiple layers via an insulating layer and having conductive paths on both sides;
A first circuit element electrically connected to a surface of the wiring board;
A second circuit element electrically connected to the back surface of the wiring board and a connection means;
A circuit module, wherein the second circuit element is positioned in a space formed by disposing the connecting means on the wiring board. A wiring board formed in multiple layers via an insulating layer and having conductive paths on both sides;
An image sensor electrically connected to the surface of the wiring board;
A lens mount that is provided on the wiring board and fixes a lens above the image sensor;
Comprising circuit elements and connection means electrically connected to the back surface of the wiring board;
A circuit module, wherein the circuit element is positioned in a space formed by arranging the connection means on the wiring board. A wiring board formed in multiple layers via an insulating layer and having conductive paths on both sides;
An image sensor electrically connected to the surface of the wiring board;
A lens mount that is provided on the wiring board and fixes a lens above the image sensor;
Comprising a circuit element electrically connected to the back surface of the wiring board;
A circuit module, wherein a part of the conductive path formed on the back surface of the wiring board is an electrode for electrically connecting to a protruding electrode provided on the mounting board side. A wiring board formed in multiple layers via an insulating layer and having conductive paths on both sides;
An imaging element and a circuit element electrically connected to the surface of the wiring board;
A lens mount that is provided on the wiring board and fixes a lens above the image sensor;
The lens mount is supported by a support, and a light-shielding wall for connecting the wiring board and the lens mount is provided around the imaging element, and the circuit element is disposed at a peripheral end of the wiring board. A circuit module characterized by that.   5. The circuit module according to claim 2, wherein the circuit element is an element that performs driving of the imaging element and signal processing of the imaging element. 6.   5. The circuit module according to claim 2, wherein the image pickup device is a semiconductor device formed of a CCD or a CMOS.   The circuit module according to claim 1, wherein a chip capacitor and a chip resistor are mounted on the back surface of the wiring board.   5. The circuit module according to claim 2, wherein a chip capacitor and a chip resistor are mounted around the image pickup device and are sealed by the lens mount.   The circuit module according to claim 1, wherein the connecting means has a core made of resin inside, and a conductive layer is formed around the core.   3. The circuit module according to claim 1, wherein a surface opposite to the mounting surface of the circuit element is located above a lower surface of the connection means. 4.   The circuit module according to claim 1, wherein the connecting means is formed at a peripheral corner portion excluding a central portion of a side edge of the wiring board.

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