KR100769729B1 - Camera module package - Google Patents

Abstract

The present invention relates to a camera module package using a flexible printed circuit board having via holes.

The camera module package of the present invention includes an image sensor having a light receiving unit at a central portion of an upper surface thereof, and a plurality of bumps formed at an outer side thereof; A flexible printed circuit board having a pad electrically connected to the bump and disposed on a lower surface of the pad and having a via hole having a via hole land overlapping a portion of the pad and bonded to the top of the image sensor by flip chip bonding; And an optical unit comprising a housing seated on an upper portion of the flexible printed circuit board, and a lens barrel screwed to an upper center portion thereof. It includes, there is an advantage of preventing the cracking phenomenon of the bump and increase the contact area of the pad and bump firmly coupled to the substrate and the image sensor.

Description

Camera module package

1 is an assembled perspective view showing an assembled state of a conventional COF type camera module.

Figure 2 is a partial cutaway cross-sectional view of a conventional COF type camera module.

3 is an exploded perspective view of flip chip bonding of an image sensor in a conventional COF package.

Figure 4 is an assembled perspective view of the image sensor flip chip bonding of the conventional camera module package.

FIG. 5 is an enlarged sectional view of a portion “I” of FIG. 4.

Figure 6 is a bottom perspective view of a flexible printed circuit board of the camera module package according to the present invention.

FIG. 7 is an enlarged cross-sectional view of the portion “II” of FIG. 6.

8 is an enlarged bottom view of the flexible printed circuit board of the camera module package according to the present invention;

9 is a cross-sectional view of the camera module package according to the present invention.

<Explanation of symbols for main parts of the drawings>

110.Image Sensor 111.Bump

120. Flexible printed circuit board 121. Via hole

122.Via Holland 123.Pad

The present invention relates to a camera module package using a flexible printed circuit board having a via hole, and more particularly, a via hole having a via hole land partially overlapping a pad formed on a bottom surface of a flexible printed circuit board on which an image sensor is flip chip bonded. The present invention relates to a camera module package capable of improving the design freedom of the substrate while minimizing the size of the flexible printed circuit board.

Nowadays, portable terminals such as mobile phones and PDAs are being used as a multi-convergence with music, movies, TV, and games as well as simple telephone functions with the development of the technology. The camera module is the most representative. The camera module is changing from the existing 300,000 pixels (VGA level) to the high pixel center of 8 million pixels or more, and is being changed with the implementation of various additional functions such as auto focusing (AF) and optical zoom. It is being applied to various IT devices such as camera phones, PDAs, smart phones, and other mobile communication devices.

Such a camera module is manufactured using an image sensor such as a CCD or a CMOS as a main component, and collects an image of an object through the image sensor and stores it as data in a memory in the device, and the stored data is stored in the LCD or PC in the device. The image is displayed through a display medium such as a monitor.

Recently, the camera module has been developed in a package form to realize miniaturization and thinning based on the improvement of pixels and functions in accordance with the trend of miniaturization and slimming of portable mobile communication devices, and is typically a flip chip method. COF (Chip On Film), a wire bonding type of COB (Chip On Board), and CSP (Chip Scaled Package) are produced in the form of a package, among which the COF packaging structure with reference to the drawings shown below The following is a brief look.

1 is an assembled perspective view showing an assembled state of a conventional COF type camera module, Figure 2 is a partial cutaway cross-sectional view of the conventional COF type camera module.

As shown in the drawing, the conventional camera module 1 includes a housing 2 in which an image sensor 3 for converting an image signal input through a lens into an electrical signal is supported on a bottom thereof, and the image sensor 3 of the subject. The lens group 4 for collecting the video signal and the barrel 5 in which the lens group 4 is stacked in multiple stages are constituted by a sequential combination.

In this case, a flexible printed circuit board (FPCB) 6 having a chip component such as a capacitor and a resistor, which is an electrical component for driving the image sensor 3 made of a CCD or a CMOS, is electrically connected to the lower portion of the housing 2. Combined.

The conventional camera module 1 configured as described above has an anisotropic film (ACF) between the substrate 6 and the image sensor 3 in a state where a plurality of circuit components are mounted on the flexible printed circuit board FPCB 6. A conductive film (8) or a non-conductive paste (NCP) is inserted and adhesively fixed to be energized by applying heat and pressure, and the IR filter 7 is attached to the opposite side.

Further, as described above in the state in which the barrel 5 in which the lens groups 4 are embedded and the housing 2 are temporarily coupled by screwing, the pre-assembled mounting substrate 6 is the housing 2. The bottom of the adhesive is fixed by a separate adhesive.

Since the COF-type camera module package having such a structure does not need a space for attaching the wire above all, the package area is reduced, and the height of the barrel can be reduced, thereby making it possible to reduce the thickness of the camera module.

In addition, since a flexible printed circuit board in the form of a thin film is used, a highly reliable package capable of withstanding external shocks is possible, and a manufacturing process thereof is relatively simple. In addition, the COF method can meet the trend of high-speed processing, high density, and multiple pinning due to miniaturization and reduction of resistance.

However, the COF camera module package is limited to an image sensor due to the disadvantage that the process cost is high and the delivery time is unstable as it is aggregated into a wafer level package having a minimum chip size. Due to the single-layer structure, the module using the image sensor more than the recent mega (mega) class, where various functions are added, has a disadvantage in that it does not meet the miniaturization of the module package, which was an inherent advantage.

In addition, in the case where the flexible printed circuit board 6 is a single-sided flexible printed circuit board 6, the bonding surface of the image sensor 3 attached to the lower surface thereof is limited to the lower surface of the substrate 6. (3) and the starting point of the electrical connection of each of the connection terminals provided in the flexible printed circuit board 6 must start from the lower surface of the flexible printed circuit board 6, thereby increasing the circuit design space for connecting the respective terminals. As a result, the size of the flexible printed circuit board 6 is large, and thus there is a problem that the thickness of the flexible printed circuit board 6 is reversed.

In addition, as shown in FIG. 3, a flip chip type module is fabricated using a 2-layer FPCB having a plurality of via-holes, but a double-sided flexible printed circuit board 6 is manufactured. When the image sensor 3 is tightly coupled to the bottom surface of the bump bonding portion 6a on which the plurality of bumps 3a formed on the upper surface of the image sensor 3 are contacted on the double-sided flexible printed circuit board 3. Since the plurality of via holes 6b are inevitably formed with a distance d of at least 150 μm to prevent a short circuit due to interference between the via holes 6b, the via holes 6b In the design of a circuit through the design of the circuit), the problem of space limitation caused by the circuit pattern design within a limited space is pointed out.

In order to solve such a problem, a via hole is formed at a junction thereof to correspond to the bumps of the image sensor as shown in FIGS. 4 and 5, and includes a flexible printed circuit board in which the bump and the via hole are closely coupled. A patent entitled “camera module package” has been filed by the present applicant (Application No. 2006-44616). Such a conventional camera module package includes an image sensor 21 and a flexible printed circuit board 25. When the bump 22 of the bump 22 and the via hole 27 are in direct contact with each other, the bump 22 is broken by the heat and pressure generated during the flip chip process of the substrate 25 and the image sensor 21 using heat and pressure. The problem that occurs is pointed out.

In addition, since only a part of the plating layer 27a excluding the bump 22 of the image sensor 21 and the via hole 27 formed in the flexible printed circuit board 25 is bonded, the contact area thereof is reduced to thereby bond strength. There is a disadvantage that is lowered.

Therefore, the present invention was devised to solve the above-mentioned disadvantages and problems that may occur in the conventional flip chip type camera module manufacturing method, and includes a pad and a pad on a flexible printed circuit board which are closely coupled by an image sensor and a flip chip. Through-holes formed by overlapping portions of the via-hole lands are formed through the camera module package to improve the degree of freedom in designing the circuit pattern of the flexible printed circuit board and to eliminate the space constraint of the circuit design through the via-holes. There is provided an object of the invention.

The object of the present invention, the image sensor is provided with a plurality of bumps at equal intervals along the upper edge, and the pad is provided with a close contact with the bump on the upper portion of the image sensor has a via hole land overlapping a portion with the pad A camera module package includes a flexible printed circuit board having via holes formed therein, an optical unit including a housing seated on an upper portion of the flexible printed circuit board and a lens barrel vertically coupled to an upper center portion thereof.

The image sensor is provided with a plurality of connection bumps arranged in a row on the outside of the light receiving portion formed in the center portion, the flexible printed circuit board is tightly coupled by the image sensor and the flip chip method has a light receiving area exposed to the light receiving portion in the center Perforated

In addition, a plurality of pads are provided on a lower surface of the flexible printed circuit board at positions corresponding to the connection bumps formed along the upper edge of the image sensor, and the width of the via hole generated when the via hole is generated inside the pad. Via holes are formed in the spaced apart position. That is, a part of the pad and the via hole land overlap each other.

In this case, the flexible printed circuit board is preferably formed of a double-sided flexible printed circuit board is a circuit pattern formed on the upper, lower surfaces electrically connected via via holes.

The via hole is mainly made of a micro via hole which is drilled by laser drilling and has excellent flatness of the drilled portion, and is formed to penetrate the upper and lower surfaces of the flexible printed circuit board.

The perforation diameter is formed within about 50 μm, and is formed on the inner wall surface of the via hole land and the metal film connecting the via hole lands to adjacent positions of the upper and lower sides, and the via hole lands are joined to the connection bumps of the image sensor. Is electrically connected to the pad.

In this case, the via hole land and the metal film of the via hole may be formed of an Au (gold) or Cu (copper) plating layer.

Meanwhile, the manufacturing of the camera module is completed by mounting a housing in which a lens barrel is mounted at the center of the image sensor module coupled to the bottom surface of the flexible printed circuit board by flip chip bonding.

Matters relating to the operational effects including the technical configuration of the camera module package of the present invention will be clearly understood by the following detailed description with reference to the drawings in which preferred embodiments of the present invention are shown.

First, FIG. 6 is a bottom perspective view of a flexible printed circuit board of the camera module package according to the present invention, FIG. 7 is an enlarged cross-sectional view of a portion “II” of FIG. 6, and FIG. 8 is a flexible printed circuit of the camera module package according to the present invention. 9 is a cross-sectional view of the camera module package according to the present invention.

As shown, the camera module package 100 of the present invention is an image sensor 110 having a bump 111 on the upper surface, a plurality of pads 123 bonded to the bump 111 and vias therein. A flexible printed circuit board 120 having a hole 121 is formed, and an optical unit 130 mounted on an upper portion of the flexible printed circuit board 120.

The image sensor 110 includes a light receiving unit (not shown) in which microlenses are densely arranged in the center of the image, and a plurality of connection bumps 111 are arranged in a line along an edge of the image sensor 110 outside the light receiving unit. .

The bumps 111 are manufactured in the form of plated bumps or stud bumps, and electrically connected to the pads 123 of the flexible printed circuit board 120 that are tightly coupled to the upper portion of the image sensor 110. By being in contact with each other, the electrical signal generated through the image sensor 110 may be transmitted to the external device through the flexible printed circuit board 120.

In the flexible printed circuit board 120 to which the image sensor 110 is flip chip bonded, a light receiving area 125 in which a light receiving portion of the image sensor 110 is exposed is drilled in a central portion thereof, and both surfaces thereof are predetermined circuits. The patterned pattern is formed of a double-sided flexible printed circuit board having a uniform plating layer, and a plurality of pads 123 are formed at edge portions thereof, that is, positions corresponding to the bumps 111 of the image sensor 110.

In addition, a plurality of via holes 121 for connecting a circuit pattern formed in the flexible printed circuit board 120 to one side of the pad 123, preferably inside the pad 123, with each pad 123. Is formed.

The via holes 121 correspond one-to-one with the plurality of pads 123 and are aligned in line with the inside of the pads 123, and each of the via holes 121 is connected to the via hole land 122 to an adjacent point of the outside thereof. Is provided.

The via hole 121 is processed by laser drilling and consists of micro via holes penetrating the upper and lower portions of the flexible printed circuit board 120, and the diameter of the via hole 121 is about 50 μm or less. It forms a small through hole of the flexible printed circuit board 120 serves as a passage for conducting the upper and lower portions.

In addition, the inner wall surface of each via hole 121 is mainly formed of a metal film 121a using Au (gold) or Cu (copper) for conduction of the upper and lower surfaces of the substrate 120 through the via hole 121. The via hole land 122 around the via hole 121 is formed by patterning that is performed to the outside of the metal film by a sputtering process performed after the punching of the via hole 121.

In this case, the via hole land 122 is formed to overlap a portion of the pad 123, so that a circuit pattern in the flexible printed circuit board 120 connected through the via hole 121 is electrically connected to the pad 123. Be sure to

Accordingly, the via holes 121 are arranged inside the pads 123 formed at points corresponding to the bumps 111 formed on the image sensor 110, which are tightly coupled to the flexible printed circuit board 120 by flip chip bonding. By aligning the substrate, the size of the substrate is minimized and the degree of freedom in designing the via hole 121 is increased as the punching position of the via hole 121 is determined to overlap the portion of the via hole land 122 and the pad 123. .

In this configuration, the flexible printed circuit board 120 to which the image sensor 110 is attached to the bottom surface of the flexible printed circuit board 120 is covered with the infrared cut filter 140 in the light receiving region 125 of the upper surface or the infrared cut filter 140. The optical unit 130 is composed of a housing 132 mounted therein and a lens barrel 131 vertically coupled to the upper portion of the housing 132.

The optical unit 130 is screw-coupled to the housing 132 and the upper center portion thereof, and consists of a lens barrel 131 equipped with at least one lens therein, the flexible unit mounted in the lower opening of the housing 132 The connector C for connecting an external device is coupled to the free end side of the printed circuit board 120.

Meanwhile, the flexible printed circuit board 120 having the optical unit 130 coupled thereon has a pad 123 having a portion overlapped with a via hole land 122 of each via hole 121 at an edge portion thereof. When the bump 111 of the image sensor 110 is correspondingly bonded, the bump 111 and the pad 123 are bonded and fixed with the ACF 150 or the NCP bond interposed therebetween.

In this case, due to relatively high temperature and pressure during flip chip bonding of the flexible printed circuit board 120 and the image sensor 110, the front surface of the bump 111 formed on the image sensor 110 may be in close contact with the pad 123. Combination prevents the bumps 111 from being broken and at the same time, the bumps 111 are electrically connected to the via holes 121, and the contact area thereof is increased.

Preferred embodiments of the present invention described above are disclosed for the purpose of illustration, and various substitutions, modifications, and changes within the scope without departing from the spirit of the present invention for those skilled in the art to which the present invention pertains. It will be possible, but such substitutions, changes and the like should be regarded as belonging to the following claims.

As described above, the camera module package of the present invention has a via having a via hole land in which a flexible printed circuit board bonded by a bump formed on the upper surface of the camera module package is overlapped with a pad provided on the lower surface of the flexible printed circuit board. By forming holes, the bumps are prevented from being broken and the pads and bumps are contacted with each other to increase the contact area, and the substrate and the image sensor are firmly coupled to each other. There is an advantage that can reduce the module size by.

Claims (5)

An image sensor having a light receiving unit at a central portion of an upper surface thereof, and having a plurality of bumps formed at an outer side thereof; A flexible printed circuit board having a pad electrically connected to the bump and disposed on a lower surface of the pad and having a via hole having a via hole land overlapping a portion of the pad and bonded to the top of the image sensor by flip chip bonding; And An optical unit including a housing seated on an upper portion of the flexible printed circuit board and a lens barrel screwed to an upper center portion thereof; Camera module package comprising a. The method of claim 1, The via hole is a camera module package, characterized in that formed in the center of the pad spaced apart by the interval of the via hole land. The method of claim 1, The via hole is a camera module package, characterized in that formed with a micro via (micro via) penetrating the flexible printed circuit board vertically. The method according to claim 1 or 3, The via hole land is formed of an Au (gold) or Cu (copper) plating layer extending from the metal film on the inner wall surface of the via hole, the camera module package, characterized in that the portion in contact with the pad electrically. The method of claim 1, The flexible printed circuit board is a camera module package, characterized in that the double-sided flexible printed circuit board.

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