JP2007150101A - Module board and imaging device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To take countermeasures to EMC while attaining the miniaturization of a module board. <P>SOLUTION: A module board comprises a printed wiring board 22 where an electric conductive layer 27 is formed while electronic components 23 are mounted in a surface 22a; and a shield case 24 for covering the electronic components 23 mounted in the surface 22a of the printed wiring board 22, where one surface is opened and connected to the surface 22a of the printed wiring board 22. An electric conductive layer 27 formed in the printed wiring board 22 is provided in the region of the whole surface to the mounting surface side of the electronic components 23 mounted in the surface 22a of the printed wiring board 22 at least. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a printed wiring board built in an electronic device, and more particularly, to a module board in which electronic components are mounted and modularized, and an imaging apparatus using the module board.

  2. Description of the Related Art Conventionally, portable information terminals such as mobile phones, notebook personal computers, and PDAs (Personal Digital Assistants) in which an imaging device is incorporated are provided. An imaging device incorporated in this type of portable information terminal includes an imaging lens, a lens barrel that holds the imaging lens, and a CCD or CMOS that receives light incident from the imaging lens and generates a video signal. Such an image sensor and a video signal output from the image sensor are input, and a signal processing circuit that performs predetermined signal processing is often provided as a camera module formed as a module.

  Such a camera module is also required to be downsized and highly functional along with downsizing and high functionality of portable information terminals. In addition, with a dramatic increase in the operating frequency of a circuit, a countermeasure for unnecessary radiation that impedes normal operation of a camera module or a portable information terminal is emphasized. In other words, in mobile phones and laptop computers equipped with camera modules, the communication function is hindered by unnecessary radiation generated by the camera modules, or by unnecessary radiation generated by the use of mobile phones and laptop computers. Function may be inhibited. As a countermeasure against such EMC (Electromagnetic Compatibility), for example, a camera module is shielded with a shield case (Patent Document 1).

  In the camera module described in Patent Document 1, a shield case including a front case and a rear case is provided, and by storing the camera module in the front case and the rear case, unnecessary radiation generated from the camera module is suppressed, Further, unnecessary radiation generated by using the portable information terminal is prevented from affecting the camera module.

  However, since the camera module described in Patent Document 1 covers the camera module by combining the front case and the rear case, the entire shield case is increased in size, and the portable information terminal is reduced in size and thickness. It becomes difficult to respond to the request. The shield case is made of a conductive material such as aluminum, and it is necessary to drop the ground onto the mounting board. However, it is difficult to solder the shield case to the mounting board. Furthermore, two cases of a front case and a rear case are required, which is disadvantageous in terms of cost.

  In addition, in order to reduce the size of the shield case, there are some that are attached so as to cover the camera module using only the case on one side, but there is a limit to the shielding effect because the opposite side is open .

JP-A-2005-86341

  The present invention has been made in view of such circumstances, and an object of the present invention is to provide a module substrate that is advantageous in taking measures against EMC while reducing the size of a camera module and an imaging apparatus using the module substrate.

  In order to solve the above-described problem, a module substrate according to the present invention includes a printed wiring board on which an electronic component is mounted and a conductive layer is formed, and one surface is opened, and the opened surface is used as the printed wiring board. And a shield case covering the electronic component mounted on the surface of the printed wiring board, and the conductive layer formed on the printed wiring board is at least of the printed wiring board. The electronic component mounted on the surface is provided over the entire surface with respect to the mounting surface side.

  An imaging device according to the present invention includes an imaging lens held by a lens barrel, and an imaging element that is mounted on an insulating substrate on which the lens barrel is erected and receives light incident from the imaging lens. A camera module, a printed wiring board on which an electronic component is mounted and a conductive layer is formed, and one surface is opened, and the printed surface is joined to the surface of the printed wiring board. A shield case that covers the electronic component mounted on the surface of the wiring board, and the conductive layer formed on the printed wiring board is at least a mounting surface of the electronic component mounted on the surface of the printed wiring board And a module substrate provided on the entire surface with respect to the side, and the insulating substrate of the camera module and the module substrate are laminated.

  According to the module substrate and the imaging device according to the present invention, the electronic component covers the surface excluding the mounting surface to the printed wiring board by the shield case, and the conductive layer is formed over the entire area with respect to the mounting surface of the printed wiring board. By covering the open surface of the shield case, it is possible to take EMC countermeasures for electronic components as in the case where the entire module substrate is housed in the shield case. In particular, when applied to an image pickup apparatus, a large EMC effect can be obtained by mounting an electronic component that generates a lot of unnecessary radiation on a printed wiring board and shielding its periphery with a shield case and a conductive layer.

  In addition, the module substrate and the imaging device are not housed entirely in the shield case, and only the electronic components are covered with the shield case and the conductive layer, so that the entire shield case is not reduced in size, It is possible to easily meet the demand for thinning.

  Hereinafter, a module substrate and an imaging device to which the present invention is applied will be described in detail with reference to the drawings, taking as an example a case where the module substrate and the imaging device are incorporated in a mobile phone 1. As shown in FIG. 1, the cellular phone 1 to which the present invention is applied has upper and lower cases 2 and 3 connected to each other by a hinge portion 4 so as to be opened and closed. A lens window 5 is provided on the surface of one upper case 2, and an imaging device 6 is incorporated inside the lens window 5.

  As shown in FIG. 2, the imaging device 6 includes a camera module 10 and a module substrate 11 on which the camera module 10 is mounted. The camera module 10 is mounted on the first and second imaging lenses 13 and 14 held by the lens barrel 12 and the insulating substrate 15 on which the lens barrel 12 is erected, and the first and second imaging lenses are mounted. And an image sensor 16 that receives light incident from the lenses 13 and 14.

  The lens barrel 12 constituting the camera module 10 is formed of, for example, a hollow cylindrical body whose lower end is opened, and first and second imaging lenses 13 and 14 are disposed inside the hollow. In addition, an opening 18 is formed in the closed upper end side of the lens barrel 12 so that the first and second imaging lenses 13 and 14 face outward, and a light-transmissive protective cover 19 is attached. Yes. The lens barrel 12 is mounted by bonding the end of the outer peripheral wall 12 a on the open end side to the insulating substrate 15 with an adhesive 21.

  The first and second imaging lenses 13 and 14 disposed in the lens barrel 12 are each formed of a convex lens or a concave lens, and the light taken from the opening 18 of the lens barrel 12 is input to the imaging device 16. Condensed. One or a plurality of these imaging lenses are used depending on the design, and are configured by a convex lens or a combination of a convex lens and a concave lens.

  For example, a ceramic substrate is used as the insulating substrate 15 on which the lens barrel 12 is mounted, and the imaging element 16 is mounted on a surface facing the first and second imaging lenses 13 and 14 in a rectangular recess 15a. In addition, a wiring pattern is formed, and the wiring pattern and the image sensor 16 are connected by wire bonding or the like. The image sensor 16 is a CCD or CMOS, and is covered with a transparent seal glass 20 disposed on the upper surface of the recess 15a.

  Such a camera module 10 is stacked on a module substrate 11 on which a semiconductor chip 23 that receives an image signal generated by the image sensor 16 and performs signal processing is disposed. The module substrate 11 is a multilayer printed wiring board in which a conductive layer is formed on an inner layer and an outer layer, and a semiconductor chip 23 is mounted on the surface to form a module.

  The module substrate 11 includes a multilayer printed wiring board 22 and a shield case 24 that covers the semiconductor chip 23 by being bonded to the surface 22a of the multilayer printed wiring board 22 on which the semiconductor chip 23 is mounted. The module substrate 11 constitutes the imaging device 6 by mounting the insulating substrate 15 of the camera module 10 on the back surface 22b opposite to the front surface 22a on which the semiconductor chip 23 is mounted.

  The multilayer printed wiring board 22 is a printed wiring board in which a conductive layer is formed on an inner layer and a surface 22a on which a semiconductor chip 23 is mounted. For example, a core board serving as a base is drilled with a laser beam and filled with a conductive paste. Then, the copper foil is laminated to form a double-sided board. And after creating the surface pattern, it builds up by repeating the process of laminating | stacking the prepreg and copper foil with which the electrically conductive paste was filled, and forming the surface pattern.

  The multilayer printed wiring board 22 is prepared by preparing a plurality of substrates on which conductive patterns and plated through holes are formed by etching or plating a metal foil such as a copper foil attached to a core substrate. The prepreg and these substrates may be laminated and laminated together by heat and pressure, or may be formed by a known method.

  As a result, the multilayer printed wiring board 22 has a shield layer 27 (to be described later) and a wiring pattern 28 connected by a conductive paste, a plated through hole, or the like over the inner and outer layers via the insulating layer 29.

  The multilayer printed wiring board 22 is provided with a bonding portion 26 where a mounting portion 25 of the semiconductor chip 23 and a shield case 24 covering the semiconductor chip 23 mounted on the mounting portion 23 are bonded to the outermost surface 22a. Yes. The mounting portion 25 is formed with, for example, an insulating layer formed in a substantially rectangular shape according to the shape of the semiconductor chip 23, and terminal portions such as lands and bonding pads to which the junction terminals of the semiconductor chip 23 are connected. The terminal portion is connected to the inner layer pattern by a via hole. One or a plurality of mounting portions 25 are formed according to the number of semiconductor chips 23 to be mounted. The bonding region 26 of the shield case 24 covering the semiconductor chip 23 is formed of a conductive pattern provided so as to surround the mounting portion 25, and is formed in, for example, a substantially rectangular frame shape according to the shape of the shield case 24. Yes.

  The semiconductor chip 23 mounted on the mounting unit 25 is an electronic component that generates a lot of unnecessary radiation such as a DSP (Digital Signal Processor) that performs signal processing of an imaging signal generated by the imaging device 16, for example. When the semiconductor chip 23 is mounted on the multilayer printed wiring board 22, the semiconductor chip 23 is electrically connected to the imaging element 16 of the camera module 10 similarly mounted on the multilayer printed wiring board 22, and an imaging signal is transmitted from the imaging element 16. .

  Further, the shield case 24 covering the semiconductor chip 23 suppresses unnecessary radiation generated from the semiconductor chip 23 so that the operation of the electronic device in which the imaging device 6 such as the mobile phone 1 is incorporated is not affected. This is to improve the immunity of the semiconductor chip 23 against radio wave interference caused by operation of the device. The shield case 24 is a box-shaped member with one surface open, and is formed of a conductive material such as aluminum. The shield case 24 is formed such that a joining piece 24a to the multilayer printed wiring board 22 is bent outward at an end portion on the open surface side of the side wall. The shield case 24 is placed with the open surface facing the one surface 22a side of the outer layer of the multilayer printed wiring board 22, and the joining piece 24a is joined to the joining region 26 by a conductive paste 31 such as solder. The semiconductor chip 23 is housed inside, thereby covering the semiconductor chip 23. The shield case 24 can be appropriately selected from a rectangular box shape, a hemispherical shape, etc., as long as one surface directed to the outer layer of the multilayer printed wiring board 22 is open.

  In the printed wiring board 22, a conductive layer is formed on the entire surface of the mounting surface 23 a of the semiconductor chip 23 covered with the shield case 24, and this conductive layer serves as a shield layer 27 that shields unnecessary radiation of the semiconductor chip 24. Yes. Then, the imaging device 6 includes the shield case 24 joined to the surface 22a of the multilayer printed wiring board 22 and the shield layer 27 formed on the multilayer printed wiring board 22 so that the EMC for the semiconductor chip 23 is sandwiched between the semiconductor chip 23. Effective measures can be taken. That is, the semiconductor chip 23 mounted on the multilayer printed wiring board 22 is covered with the shield case 24, and the shield layer 27 formed on the multilayer printed wiring board 22 functions as a lid on the open end face side of the shield case 24. The effect of covering all the directions of the semiconductor chip 23 can be obtained, whereby electromagnetic shielding can be achieved.

  The shield layer 27 is a conductive layer made of, for example, a copper foil attached to an insulating layer, and is formed in at least one layer on the inner layer and / or the outer layer of the multilayer printed wiring board 22. The shield layer 27 is formed over at least a region covering the mounting portion 25 on which the semiconductor chip 23 is mounted, that is, at least a region overlapping with the mounting portion 25.

  3 and 4, when the shield layer 27 is formed in the inner layer of the multilayer printed wiring board 22, the shield layer 27 is bonded to the bonding region 26 via the via hole 30 formed in the multilayer printed wiring board 22. The shield case 24 is connected. As a result, the module substrate 11 covers the semiconductor chip 23 with the shield case 24, the via hole 30, and the shield layer 27, thereby achieving electromagnetic shielding.

  When the shield layer 27 is formed on the surface 22a of the multilayer printed wiring board 22, the shield layer 27 is formed continuously with the bonding region 26, and an insulating layer is formed on the shield layer 27. A semiconductor chip 23 is mounted thereon. When the shield layer 27 is formed on the back surface 22 b of the multilayer printed wiring board 22, the via hole 30 is formed from the joining region 26 to the back surface 22 b and connected to the shield case 24. Furthermore, one or more shield layers 27 may be formed on the front and back surfaces 22a, 22b and / or the inner layer of the multilayer printed wiring board 22.

  In addition, when the back surface 22b side of the multilayer printed wiring board 22 is used as a mounting surface for other electronic components, the inner layer and the front surface 22a excluding the back surface 22b can be used as the formation region of the shield layer 27.

  The module substrate 11 covers the surface of the semiconductor chip 24 except for the mounting surface 23a to the multilayer printed wiring board 22 by the shield case 24, and covers the entire area of the multilayer printed wiring board 22 with respect to the mounting surface 23a. By covering the open surface of the shield case 24 with the shield layer 27 formed over, the EMC countermeasure of the semiconductor chip 24 can be achieved as in the case where the entire module substrate is housed in the shield case. In particular, when applied to the image pickup apparatus 6, most of the unnecessary radiation is generated from the DSP. Therefore, the DSP is mounted on the multilayer printed wiring board 22 and its periphery is shielded by the shield case 24 and the shield layer 27. Thus, a large EMC effect can be obtained.

  The module substrate 11 is not entirely accommodated in the shield case, and only the semiconductor chip 24 is covered with the shield case 24 and the shield layer 27, so that the entire shield case is not increased in size and reduced in size. Therefore, it is possible to easily meet the demand for thinning. Further, the module substrate 11 can be reduced in weight because only one shield case 24 whose one side is open can be used as an EMC countermeasure. Further, the semiconductor chip 24 can be mounted on the multilayer printed wiring board 22 by a normal mounting process, and the shield case 27 can be easily joined to the multilayer printed wiring board 22 by soldering or the like.

  The module substrate 11 and the image pickup apparatus 6 using the module substrate 11 have been described above. However, the module substrate to which the present invention is applied is not limited to the DSP that processes the image pickup signal transmitted from the image pickup device 16 as the semiconductor chip 23. Various semiconductor chips can be used and are not necessarily limited to those used in combination with a camera module. Even if the multilayer printed wiring board 22 has the semiconductor chip 23 and the shield case 24 mounted on the one surface 22a of the outer layer, the shield layer 27 is provided on the inner layer and / or the outer layer, and the other surface side is not used as the mounting surface. Similarly, electromagnetic shielding by the semiconductor chip 23 can be performed.

  In addition to the multilayer printed wiring board, the substrate on which the shield layer 27 is formed may be a single-layer printed wiring board. When a single-layer printed wiring board is used, the shield layer is formed on the front surface and / or the back surface of the substrate.

1 is a perspective view showing a mobile phone to which the present invention is applied. It is sectional drawing which shows the imaging device which concerns on this invention. It is sectional drawing which shows the module board which concerns on this invention. It is sectional drawing which shows the module board which concerns on this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Mobile phone, 6 Imaging device, 10 Camera module, 11 Module board | substrate, 12 Lens barrel, 13 1st imaging lens, 14 2nd imaging lens, 15 Insulation board | substrate, 16 Imaging element, 18 Opening part, 19 Protective cover , 21 Adhesive, 22 Multilayer printed wiring board, 23 Semiconductor chip, 24 Shield case, 25 Mounting part, 26 Bonding area, 27 Shield layer, 30 Via hole, 31 Conductive paste

Claims (7)

A printed wiring board on which electronic components are mounted and a conductive layer is formed; and
One surface is opened, and the open surface is joined to the surface of the printed wiring board to provide a shield case that covers the electronic component mounted on the surface of the printed wiring board,
The module substrate, wherein the conductive layer formed on the printed wiring board is provided on at least one area of the electronic component mounted on the surface of the printed wiring board.   2. The module substrate according to claim 1, wherein the printed wiring board is a multilayer printed wiring board in which the conductive layer is formed on an inner layer and / or an outer layer.   The module substrate according to claim 1, wherein the conductive layer is connected to the shield case through a via hole formed in the printed wiring board. A camera module comprising: an imaging lens held by a lens barrel; and an imaging device that is mounted on an insulating substrate on which the lens barrel is erected and receives light incident from the imaging lens;
A printed wiring board on which an electronic component is mounted and a conductive layer is formed, and one surface is opened, and the open surface is joined to the surface of the printed wiring board, whereby the surface of the printed wiring board A conductive case formed on the printed wiring board at least over the entire area of the electronic component mounted on the surface of the printed wiring board. A module substrate provided,
An imaging device in which an insulating substrate of the camera module and the module substrate are stacked.   The imaging apparatus according to claim 4, wherein the printed wiring board is a multilayer printed wiring board in which the conductive layer is formed on an inner layer and / or an outer layer.   6. The imaging apparatus according to claim 4, wherein the conductive layer is connected to the shield case through a via hole formed in the printed wiring board.   The imaging apparatus according to claim 4, wherein the electronic component mounted on the module substrate is a signal processing unit that processes a video signal received from the imaging element.

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