Patent Document

CROSS-REFERENCE TO RELATED APPLICATION 
       [0001]    This application claims the benefit under 35 U.S.C. §119 of Korean Application No. 10-2009-0124178, filed on Dec. 14, 2009, which is hereby incorporated by reference in its entirety. 
       BACKGROUND OF THE DISCLOSURE 
       [0002]    1. Field of the Invention 
         [0003]    The present invention relates to a camera module mounted on portable terminals and a manufacturing method thereof. 
         [0004]    2. Discussion of the Related Art 
         [0005]    In recent years, demand in a small-size camera module for use in various kinds of multimedia fields such as a note-type personal computer, a camera phone, a smart device and a toy, and picture image devices such as a data terminal of a surveillance camera and a video tape recorder, has been increasing. 
         [0006]    Especially, in the case of a mobile phone, a design is conceived of a factor having an enormous impact on sales, on account of this requiring a tiny-sized camera module. 
         [0007]    The camera module manufactured using an image sensor chip such as a CCD and a CMOS, concentrates light through a lens on the image sensor chip, and converts an optical signal into an electrical signal to transfer images for displaying a subject on display media such as an LCD display device. 
         [0008]    In general, a height of a camera module corresponds to a sum of a lens height (TTL, Through The Lens), an image sensor height and a thickness of a printed circuit board. Considering that a high lens TTL causes a better resolution of a camera, a sufficient lens TTL must be ensured at a certain camera module altitude in order for the camera module to be downsized and high-effective. 
         [0009]    However, since in a conventional camera module, an image sensor is formed on the upper surface of a PCB (Printed Circuit Board), it is difficult to realize the miniaturization and high-fidelity of a camera module. 
       BRIEF SUMMARY 
       [0010]    The invention provides a miniaturization and high-performance-capable camera module and a manufacturing method thereof. 
         [0011]    According to one aspect of the present invention, a camera module is provided, including a plurality of lenses, a substrate arranged at the lower part of said plurality of lenses, an infrared blocking agent formed on the upper surface of the substrate to block infrared light and an image sensor positioned at the lower surface of the substrate to convert an optical image incident through said plurality of lenses into an electrical signal. 
         [0012]    According to another aspect of the present invention, a camera module manufacturing method is provided including an image sensor converting an incident optical image into an electrical signal. Such a method includes: coating an infrared blocking agent on the upper surface of a substrate positioned on the upper part of the image sensor for blocking infrared light; forming a first circuit pattern on the top of the infrared blocking agent using a metal composition; forming a via hole running through the lower surface and upper surface of the substrate; and sticking the image sensor into a lower surface of the substrate to electrically connect an upper surface of said image sensor to the upper surface of said substrate through the via hole. 
         [0013]    An embodiment of the present invention applies a coating of the upper surface of a substrate with an infrared blocking agent, a separate IR filter is unnecessary over prior-art technologies, and one substrate performs a role as an IR filter and a printed circuit board simultaneously, capable of lowering a cost of a camera module. 
         [0014]    Also, compared to prior-art technologies, an embodiment of the present invention can decrease the dimension of a camera module by a thickness for assignment to the image sensor using an image sensor accommodated in a space created owing to a solder ball formed height because there is no need to allocate a thickness of the camera module for the image sensor, thereby realizing the miniaturization and high-performance of a camera module. 
         [0015]    In addition, an embodiment of the present invention can improve a process yield by electrically connecting an image sensor to a substrate by a bonding and thus not performing separate processes such as a die bonding and a wire bonding, leading to curtail of its manufacturing time. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0016]      FIG. 1  is a cross-sectional view of a camera module according to an embodiment of the present invention; 
           [0017]      FIG. 2  is a flow diagram indicating a camera module manufacturing method according to an embodiment of the present invention; and 
           [0018]      FIGS. 3   a  through  3   i  are diagrams indicating a manufacture process according to a flow diagram of  FIG. 2 . 
       
    
    
     DETAILED DESCRIPTION 
       [0019]    Since the present invention can be applied with various changes thereto and several types of embodiments, specific embodiments intend to be exemplified in the drawings and minutely described in the detailed description. However, it should not be appreciated in a limiting sense of limiting the present invention to a specific example but to include all the changes, equivalents and replacements which fall in the spirit and technical scope of the present invention. 
         [0020]    While terms including ordinal numbers such as a first and a second may be used to describe various components, such components are not limited to the terms. The terms are used only for the purpose of distinguishing one component from other components. 
         [0021]    For example, a second component may be named as a first component without departing from the scope of the present invention rights, and in a similar way, the first component may be renamed as the second component. 
         [0022]    Stated that any component is “connected” or “conjunctive” to another component, it will be appreciated to be directly connected or conjunctive to the very another component or otherwise that there exists any component in the midst of them. On the other hand, stating that any component is “directly connected” or “directly conjunctive” to another component, it should be understood that any other component does not exist therebetween. 
         [0023]    Terms used in the present application are only used to describe a specific embodiment, not in a sense of limiting the invention. A singular form includes a plural form, otherwise stated in a different way in the context. In this application, the terms such as “include” or “have” indicate that there exist a characteristic, a number, a step, an operation, a component, other things recited in the specification or a combination thereof, but it should not be understood to preclude the existence or addition of one or more other characteristics, numbers, operations, substances, components or a combination of thereof. 
         [0024]    In the following, a camera module and a manufacturing method thereof according to an embodiment of the present invention will be described in detail referring to the attached drawings, but without regard to a drawing sign, an identical or corresponding component is assigned the same reference numeral and a redundant description regarding this will be omitted. 
         [0025]      FIG. 1  is a cross-sectional diagram of a camera module according to an embodiment of the present invention. 
         [0026]    As illustrated in  FIG. 1 , a camera module of the present invention includes a lens barrel  10 , a holder  20 , a substrate  30 , and an image sensor  40 . 
         [0027]    The lens barrel  10  refers to a means for fixing and protecting a plurality of lenses  1 , and the inner side of the lens barrel  10  includes a plurality of lenses  1  on which an optical image of a subject may be incident. 
         [0028]    The inner-rim surface of the holder  20  faces an outside surrounding surface of the lens barrel  10  and the holder  20  also serves as a case protecting the substrate  30  and the image sensor  40 . 
         [0029]    The substrate  30  is formed of a glass substrate, the upper surface of the substrate  30  is coated with an infrared blocking agent  31  of Ir (iridium) composition capable of blocking infrared, and the lower surface of the substrate  30  is coated with an anti-reflection agent  32  of Ar (argon) composition for inhibiting the reflection of an optical image incident through the substrate  30 . At this time, the infrared blocking agent  31  and the anti-reflection agent  32  is formed sufficiently thick not to be damaged by an etching solution in a formation course of a circuit pattern on the substrate  30 . 
         [0030]    In the present invention, the infrared blocking agent  31  is coated on the upper surface of the substrate  30 , so that there is no need of a separate IR filter over a prior-art technology and one substrate  30  can carry out a mission of an IR filter and a printed circuit board simultaneously. For that reason, a unit cost of a camera module may be lowered. 
         [0031]    Various circuit patterns  33  based on an applied device could be formed on the upper surface and the lower surface of the substrate  30 , and in order to electrically connect an upper surface circuit pattern and a lower surface circuit pattern, the substrate  30  has a plurality of via holes  34  running through the upper surface and lower surface of the substrate  30 . 
         [0032]    A circuit pattern  33  is formed through an etching after depositing or sputtering a metal composition such as Cu on the upper surface and lower surface of the substrate  30 . 
         [0033]    And, a plurality of via holes  34  is formed in the substrate  30  which electrically connects an upper surface and a lower surface of the substrate  30 , and device  50  such as a driver IC (Integrated Circuit) could be mounted on one side of the upper surface of the substrate  30 . The device  50  could be any one of an active device and a passive device. 
         [0034]    A solder ball  60  is formed on one side of the lower surface of the substrate  30 , and is electrically connected to an outer part of the camera module to transmit an image signal outputted by the image sensor  40  to other media. 
         [0035]    The image sensor  40  is accommodated in an image sensor accommodation part  70 , that is, a space except for a solder ball  60  formed spaces under the lower surface of the substrate  30 , and electrically connected by a flip chip bonding to the substrate  30 . At this time, a depth of the image sensor accommodation part  70  can be changed by an elevation of the solder ball  60 . 
         [0036]    As such, in the present invention, since the image sensor  40  is accommodated in a space created due to an elevation of the solder ball  60 , there is no need to assign a thickness of the camera module for the image sensor  40  over the prior art. Thus, by reducing a dimension of the camera module as a thickness as assigned to the image sensor  40 , miniaturization and high-efficiency of a camera module can be realized. 
         [0037]      FIG. 2  is a flow diagram indicating a camera module manufacturing method according to an embodiment of the present invention, and  FIGS. 3   a  through  3   i  are diagrams indicating a manufacture process according to a flow diagram of  FIG. 2 . 
         [0038]    As illustrated in  FIGS. 2 and 3   a , an infrared blocking agent  31  of Ir composition is coated on an upper surface of the substrate  30  of glass material at first, an anti-reflecting agent  32  of Ar composition is coated on a lower surface of the substrate  30  (S 201 ). At this time, the infrared block agent  31  and the anti-reflecting agent  32  are sufficiently thick so as not to be damaged by an etching solution in the course of forming a circuit pattern  33  on substrate  30 . 
         [0039]    As illustrated in  FIG. 3   b , a metal composition  33 - 1  such as Cu is deposited or sputtered on the upper surface and lower surface of the substrate  30  (S 202 ). 
         [0040]    And, as illustrated in  FIG. 3   c , the metal composition is etched out using an etching solution so that a desired circuit pattern  33  is only left (S 203 ). 
         [0041]    In the present invention, the etching solution refers to a solution solely etching metal compositions, thus a solution unable to etch the infrared blocking agent  31  and the anti-reflection agent  32 . 
         [0042]    As illustrated in  FIG. 3   d , in order to connect an upper surface circuit pattern  33  and a lower surface circuit pattern  33 , a plurality of via holes  34  are formed using a laser drill (S 204 ). 
         [0043]    As illustrated in  FIG. 3   e , a via hole  34  is electroless plated using metal compositions such as Cu (S 205 ). 
         [0044]    After the via hole  34  is plated, metal compositions  35  such as Ni or Au are plated on the circuit pattern  33  as shown in  FIG. 3   f  (S 206 ). 
         [0045]    Next, as illustrated in  FIG. 3   g , a lower surface of the substrate  30  is bumped with a solder ball  60  (S 207 ). 
         [0046]    As illustrated in  FIG. 3   h , devices  50  such as a driver IC is mounted on one side of the circuit pattern  33  on the upper surface of the substrate  30  using SMT (Surface Mount Technology) (S 208 ). 
         [0047]    In the next phase, as illustrated in  FIG. 3   i , an image sensor accommodation part  70  created due to an elevation of the solder ball  60  in the lower surface of the substrate  30  accommodates the image sensor  40 , which is electrically connected to the substrate  30  by means of a flip chip bonding (S 209 ). 
         [0048]    The flip chip bonding may be one process of an ACF (Anisotropic Conductive Film), an NCF (Non Conductive Film), an ACP (Anisotropic Conductive Paste), and an NCP (Non Conductive Paste). 
         [0049]    Lastly, when the substrate  30  and the image sensor  40  formed by a process of  FIGS. 3   a  through  3   i  are mounted on the holder  20 , a camera module according to an embodiment of the present invention is manufactured as shown in  FIG. 1 . 
         [0050]    The present invention electrically connects the image sensor  40  and the substrate  30  by means of a flip chip bonding, thereby shortening manufacturing time and improving process efficiency because of not performing separate processes such as a die bonding and a wire bonding. 
         [0051]    While embodiments of the present invention have been described in the previous section, it would be understood to those skilled in the art that an embodiment employing various changes and improvements also can be made thereof within the scope of the present invention using basic concepts of the present invention defined by the following claims, not limited to the above embodiment.

Technology Category: h