JP2004233482A - Camera module manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To miniaturize a camera module for portable equipment to chip size and also to reduce manufacture cost and to improve the focus accuracy. <P>SOLUTION: An IR filter 30 is stuck to a lens 40. Then, a distance h<SB>1</SB>from the back surface of the filter 30 to the center position of a lens main body 41 is measured. When the distance h<SB>1</SB>exceeds specified tolerance, the back grind process of the filter 30 is performed to make the distance h<SB>1</SB>kept within the tolerance, and the focusing of the lens is performed. Thereafter, the lens 40 to which the filter 30 is stuck is stuck to an image sensor chip 20. Since the lens and the filter member are stuck to the chip 20 and are integrated, the camera module is miniaturized to the chip size and also the manufacture cost is drastically reduced. Then, a stage for grinding the filter member or the lens before sticking the lens is provided and then the focusing of the lens is performed, so that the focus accuracy of the camera module is improved. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a method for manufacturing a camera module, and more particularly to a method for manufacturing a small-sized camera module suitable for being incorporated in a portable device such as a mobile phone.
[0002]
[Prior art]
In recent years, mobile phones having a camera function have become widespread. This type of mobile phone has a built-in small camera module. FIG. 13 is a sectional view showing the structure of such a camera module.
[0003]
In FIG. 13, reference numeral 50 denotes a lens barrel, 51 denotes a lens incorporated in the lens barrel 50, and 52 denotes an IR cut-off IR filter provided at the lens barrel opening of the lens barrel 50. Reference numeral 60 denotes an image sensor chip housed in the space inside the lens barrel 50 and electrically connected to the printed board 70.
[0004]
The image sensor chip 60 converts the light from the subject incident through the IR filter 52 and the lens 51 into an electric signal. In this image sensor chip 60, a CCD is formed on the surface of a silicon chip 61, and a supporting glass substrate 62 for supporting the silicon chip 61 is bonded thereon.
[0005]
Further, electrode pads 63A and 63B are formed around the surface of the image sensor chip 60, and rewirings 64A and 64B from the side surface to the back surface of the silicon chip 61 are formed.
[0006]
The rewirings 64A, 64B extend on a glass substrate 65 bonded to the back surface of the silicon chip 61, and bump electrodes 66A, 66B are formed at the ends of the rewirings 64A, 64B extending on the glass substrate 65. Have been. The bump electrodes 66A and 66B are connected to the printed circuit board 70.
[0007]
A DSP 80 that receives an electric signal from the image sensor chip 60 and performs predetermined image signal processing on the signal is connected to the back surface of the printed board 70 via bump electrodes 81A and 81B.
[0008]
Note that this type of camera module is described in Patent Documents 1-3. Patent Document 4 describes a chip structure in which bump electrodes are provided on the back surface.
[0009]
[Patent Document 1]
JP-A-9-61239
[Patent Document 2]
Japanese Patent Application Laid-Open No. H11-260144
[Patent Document 3]
Japanese Patent Application No. 2001-128072
[Patent Document 4]
Patent Publication No. 2002-512436
[Problems to be solved by the invention]
However, in the above-described camera module, each of the lens barrel 50, the lens 51, the IR filter 52, and the image sensor chip 60 is an individual component, and the individual equipment is assembled to assemble the camera module. Therefore, there is a problem that the size of the camera module is limited and the manufacturing cost is high.
[0014]
[Means for Solving the Problems]
Therefore, in a method of manufacturing a camera module according to the present invention, a filter member and a lens are attached to an image sensor chip having a photoelectric conversion element disposed on a front surface and external connection terminals disposed on a rear surface. Then, before attaching the filter member to the image sensor chip, a grind for adjusting the focus of the lens is applied to the filter member or the lens.
[0015]
BEST MODE FOR CARRYING OUT THE INVENTION
Next, embodiments of the present invention will be described in detail with reference to the drawings.
First, the structure of the camera module will be described. FIG. 1 is a plan view of the camera module, and FIG. 2 is a sectional view taken along line XX of FIG.
[0016]
This camera module is basically one in which the lens 10 and the image sensor chip 20 are bonded and integrated, and an IR filter 30 is further bonded on the lens 10, and an aperture member 31 is placed on the IR filter 30. It is provided. Light from the subject passes through the IR filter 30 and the lens 10 and is focused on the surface of the image sensor chip 20 to form an image.
[0017]
More specifically, the lens 10 includes a lens body 11 that is circular in plan view, and a lens frame 12 provided around the lens body 11 and integrally formed with the lens body 11. The lens frame 12 extends beyond the lens surface, and the bottom surface is bonded to the periphery of the surface of the image sensor chip 20 using an adhesive or the like. The upper surface of the lens frame 12 is bonded to the IR filter 30 using an adhesive or the like. The lens 10 can be manufactured by, for example, injection molding or the like, in which case it is made of plastic.
[0018]
The aperture member 31 is made of a film such as an acrylic film or a polyolefin film, and is attached to the IR filter 30. The aperture member 31 may be configured by printing a light shielding material on the surface of the IR filter 30 or the lens body instead of such a film.
[0019]
In the image sensor chip 20, a CCD as a photoelectric conversion element is formed on the surface of the silicon chip. The CCD converts light formed on the surface of the image sensor chip 20 through the IR filter 30 and the lens 10 into an electric signal. A support glass substrate 22 for supporting the silicon chip 21 is bonded on the CCD using an adhesive or the like. Further, electrode pads 23A and 23B are formed around the surface of the silicon chip 21. These electrode pads 23A and 23B are connected to the input / output circuit of the image sensor chip 20.
[0020]
On the lower surfaces of the electrode pads 23A and 23B, rewirings 24A and 24B that penetrate the silicon chip 21 and reach the back surface of the image sensor chip 20 are connected. Bump electrodes 25A and 25B, which are external connection terminals, are formed thereon.
[0021]
In the configuration of FIG. 2, the IR filter 30 is bonded on the lens 10, but the IR filter 30 may be bonded between the image sensor chip 20 and the lens 10, as shown in FIG. By doing so, the length L of the legs of the lens frame 12 can be shortened by the thickness of the IR filter 30, and the injection molding thereof is facilitated.
[0022]
According to the camera module having the above configuration, since the lens 10, the image sensor chip, the IR filter, and the aperture member 31 are integrated, the size can be reduced as compared with the conventional example, and the manufacturing cost can be reduced. Can also be planned.
[0023]
In the above configuration, if the support glass substrate 22 for supporting the silicon chip 21 has a filter function, the IR filter 30 can be omitted, so that the cost can be reduced by reducing the number of components. In this case, a filter function can be obtained by performing vacuum evaporation of a metal on the supporting glass substrate 22 or mixing copper particles. Also, a filter function can be obtained by attaching a filter member made of a multilayer thin film on the surface of the lens 10. This multilayer thin film is formed by vacuum-depositing a material such as a metal having predetermined transmission characteristics. This applies to the camera module described below.
[0024]
Next, the structure of another camera module will be described. FIG. 4 is a sectional view of the camera module. In the figure, the same components as those in FIG. 2 are denoted by the same reference numerals, and description thereof is omitted. This camera module supports high image quality of 300,000 pixels or more by using two lenses.
[0025]
As shown in FIG. 4, the lens frame 42 of the lens 40 is cut off to form a lens mounting portion 43, and a glass lens 45 is mounted on the lens mounting portion 43, and further fixed with an adhesive. ing. As a result, the lens mounting portion 43 becomes a positioning portion for the glass lens 45, another glass lens 45 is superimposed on the lens body 41 at a predetermined distance, and light from the subject passes through the two lenses. It is focused on the surface of the image sensor chip 20. That is, the two lenses are positioned so that the surface of the image sensor chip 20 is in focus.
[0026]
Further, as shown in FIG. 5A, the IR filter 30 may be bonded between the image sensor chip 20 and the lens 40. By doing so, the length of the foot of the lens frame 42 can be shortened by the thickness of the IR filter 30, and the injection molding thereof is facilitated.
[0027]
In the camera module described above, the dimensions of the lens are designed such that the focal point of the lens is located on the surface of the image sensor chip 20. Specifically, in the single-lens camera module shown in FIGS. 1 to 3, the dimensions of the lens frame 12 of the lens 10 (length of the foot of the lens frame 12, from the end of the foot of the lens frame 12). The distance to the center position of the lens 10 is designed. In the two-lens camera module shown in FIGS. 4 and 5A, the dimensions of the lens frame 42 are designed. In the example of FIG. 5 (a), in consideration of the thickness of the IR filter 30, so that the distance h ₁ from the surface of the image sensor chip 20 to the center position of the lens body 41, a composite focal length of the two lenses Designed to.
[0028]
However, when the lenses 10 and 40 and the IR filter 30 are manufactured, their dimensions and thickness vary, so that the focus of the lenses 10 and 40 may be shifted. Therefore, as shown in FIG. 5B, the IR filter 30 is attached to the lens 40 using an adhesive. At this time the distance h ₁ from the back surface of the IR filter 30 to the central position of the lens body 41 is measured, which performs a back-grinding of the IR filter 30 (the back surface polishing) when exceeding a predetermined allowable range, the distance h ₁ is as entering the allowable range, adjust the focus of the lens.
[0029]
Specifically, the focus adjustment of the lens is performed so that an image of a target pixel of the CCD on the image sensor chip 20 does not enter an adjacent pixel. The pitch of the pixels of the CCD differs depending on the number of pixels, but is approximately several μm. For example, when light from a subject is refracted by about 45 degrees with a lens to form an image on a pixel of the CCD, focus adjustment in the vertical direction is also performed within an allowable range of several μm or less.
[0030]
When the IR filter 30 is not interposed between the lens and the surface of the image sensor chip 20, as shown in FIGS. 2 and 4, the lens frames 12, 42 are used for the above-described focus adjustment. After the back glide described above, the lenses 10 and 40 may be attached to the image sensor chip 20.
[0031]
Next, a method for manufacturing the camera module of FIG. 3 will be described with reference to FIG. As shown in FIG. 6, an image sensor wafer 100 having a plurality of image sensor chips 20 arranged in a matrix is prepared by a wafer process. Further, an IR filter glass 101 having a wafer shape is prepared. Further, a lens array 102 having a shape and size corresponding to the image sensor chip 20 and having a plurality of lenses 10 integrated is prepared. Also, an aperture film 103 having a wafer shape is prepared.
[0032]
Here, FIG. 7 is a plan view showing an example of the lens array 102. FIG. As shown in FIG. 7A, a large number of lenses 10 are arranged in the lens array 102, and are integrated in a wafer form as a whole. Then, as shown in FIG. 7B, the lens array 102 is attached to the image sensor wafer 100 with an adhesive or the like.
[0033]
FIG. 8 is a plan view showing another example of the lens array 102. This lens array 102 is composed of two types of divided arrays A and B having a substantially triangular shape as shown in FIG. Then, as shown in FIG. 8B, four divided arrays A and B are respectively attached to the image sensor wafer 100 with an adhesive or the like.
[0034]
FIG. 9 is a plan view showing still another example of the lens array 102. The lens array 102 is formed of one type of divided array having a rectangular shape as shown in FIG.
[0035]
Then, as shown in FIG. 9B, the 16 divided arrays are attached to the image sensor wafer 100. This lens array 102 has a merit that the portion that protrudes from the image sensor wafer 100 is wasted, but since it is composed of one type of divided array, its manufacture can be simplified.
[0036]
Then, as shown in FIG. 10, the IR filter glass 101 is attached to the lower surface of the lens array 102 with an adhesive or the like, and the aperture film 103 is attached to the upper surface of the lens array 102 with an adhesive or the like. At this time the distance h ₁ from the back surface of the IR filter 30 to the center position of the lens body 11 is measured, which performs a back-grinding of the IR filter glass 101 if it exceeds a predetermined allowable range, the distance h ₁ Is adjusted so as to fall within the allowable range.
[0037]
Next, as shown in FIG. 11, the lens array 102 to which the IR filter glass 101 is attached is attached to the image sensor wafer 100 with an adhesive or the like. At this time, the alignment is performed so that the boundary line LZ between the adjacent image sensor chips 20 substantially matches the center line of the lens frame 12.
[0038]
Next, as shown in FIG. 12, the structure shown in FIG. 11 is divided into individual camera modules 200 using a dicing blade or a laser along the boundary line LZ.
[0039]
In the case of the camera module having the structure shown in FIG. 2, since the IR filter 30 is not interposed between the lens 10 and the image sensor chip 20, the lens frame of the lens array 102 is required to adjust the focus of the lens 10. Grind 12 so as to have a predetermined thickness. In the above example, the number of lens arrays 102 is one, but two or more lens arrays may be bonded to form a compound lens.
[0040]
Also, in the case of the camera module having the structure shown in FIG. 4, since the IR filter 30 is not interposed between the lens 40 and the image sensor chip 20, a portion of the lens frame 42 of the lens array 102 is required for focus adjustment. Is ground (polished) so as to have a predetermined thickness.
[0041]
In the case of the camera module having the structure shown in FIG. 5, the IR filter glass 101 is back-ground as in the case of the camera module shown in FIG.
[0042]
The individual camera modules 200 thus manufactured are mounted on a printed circuit board via the bump electrodes 25A and 25B on the back surface of the image sensor chip 20. At this time, since the bump electrodes 25A and 25B are usually heated when mounted on a printed board, the heat resistance of the lens 10 becomes a problem when the lens 10 is made of plastic. In that case, it is preferable to use a plastic material having high heat resistance or use a gold bump which can be connected at low temperature.
[0043]
【The invention's effect】
According to the present invention, since the lens and the filter member are attached to the image sensor chip and they are integrated, the camera module can be downsized to a chip size and the manufacturing cost can be greatly reduced. In addition, before the lens is attached, a step of grinding the filter member or the lens is provided, and the focus of the lens is adjusted, so that the focus accuracy of the camera module can be improved.
[Brief description of the drawings]
FIG. 1 is a plan view of a camera module according to an embodiment of the present invention.
FIG. 2 is a sectional view taken along line XX of FIG.
FIG. 3 is a cross-sectional view of the camera module according to the embodiment of the present invention.
FIG. 4 is a cross-sectional view of the camera module according to the embodiment of the present invention.
FIG. 5 is a cross-sectional view of the camera module according to the embodiment of the present invention.
FIG. 6 is a cross-sectional view illustrating a method for manufacturing a camera module according to the embodiment of the present invention.
FIG. 7 is a plan view of a lens array.
FIG. 8 is a plan view of another lens array.
FIG. 9 is a plan view of still another lens array.
FIG. 10 is a sectional view illustrating the method for manufacturing the camera module according to the embodiment of the present invention.
FIG. 11 is a sectional view illustrating the method for manufacturing the camera module according to the embodiment of the present invention.
FIG. 12 is a sectional view illustrating the method for manufacturing the camera module according to the embodiment of the present invention.
FIG. 13 is a sectional view of a camera module according to a conventional example.
[Explanation of symbols]
Reference Signs List 10 lens 11 lens body 12 lens frame 20 image sensor chip 21 silicon chip 22 support glass substrate 23A, 23B electrode pad 24A, 24B rewiring 25A, 25B bump electrode 30 IR filter 31 diaphragm member 40 lens 41 lens body 42 lens frame Body 100 Image sensor wafer 101 Filter glass 102 Lens array 103 Aperture film

Claims (7)

A method for manufacturing a camera module, comprising: attaching a filter member and a lens to an image sensor chip in which a photoelectric conversion element is disposed on a front surface and external connection terminals are disposed on a rear surface, wherein the filter member is A method for manufacturing a camera module, characterized in that a grind for adjusting the focus of the lens is applied to the filter member or the lens before attaching to the image sensor chip. A method for manufacturing a camera module, comprising: attaching a lens to an image sensor chip having a photoelectric conversion element disposed on a front surface and external connection terminals disposed on a rear surface, wherein the lens is attached to the image sensor chip. A method for manufacturing a camera module, wherein a grind for adjusting the focus of the lens is applied to the lens before attaching the lens to the camera module. An image sensor wafer in which a plurality of image sensor chips each having a photoelectric conversion element disposed on the front surface and external connection terminals disposed on the rear surface; and a lens having a size corresponding to the size of the image sensor chip Prepare a lens array formed by integrating a plurality of and a filter member for cutting incident light in a predetermined wavelength region,
Attaching the filter member to the lens array,
A step of performing a focus adjustment of the lens by applying a grind to the filter member so as to have a predetermined thickness,
Affixing the lens array to which the filter member has been attached to the image sensor wafer via the filter member,
Dividing the image sensor chip, the filter member, and the lens into individual camera modules that are integrated with each other. An image sensor wafer on which a plurality of image sensor chips each having a photoelectric conversion element disposed on the front surface and external connection terminals disposed on the rear surface are disposed, and a size corresponding to the size of the image sensor chip. Prepare a lens array that integrates multiple lenses,
A step of grinding and adjusting the focus so that the lens array has a predetermined thickness,
Bonding the lens array to the surface of the image sensor wafer;
Dividing the image sensor chip and the lens into individual camera modules that are integrated with each other. 5. The method according to claim 3, wherein the lens array has a wafer shape. The method according to claim 3, wherein the lens array comprises an aggregate of divided arrays. 5. The method according to claim 3, wherein the lens array comprises a set of quadrangular divided arrays.

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