Abstract:
A method for manufacturing a solid-state image sensing device, includes mounting a solid-state image sensor on a substrate, forming an elastic layer on a first surface of a glass lid, fixing the glass lid onto the solid-state image sensor with a bonding agent so that the glass lid covers the solid-state image sensor while a second surface opposite to the first surface of the glass lid faces the solid-state image sensor, electrically connecting a terminal provided on the solid-state image sensor, to a terminal provided on the substrate, through a wire, and encapsulating the wire and covering a side surface of the glass lid with a resin.

Description:
TECHNICAL FIELD 
       [0001]    The present disclosure relates to a method for manufacturing a solid-state image sensing device for use in a digital camera or the like, and the solid-state image sensing device. 
       RELATED ART 
       [0002]    There are solid-state image sensing devices mounted with solid-state image sensors such as CCD image sensors or CMOS image sensors. 
         [0003]    Typically in such a solid-state image sensing device  10 , as shown in  FIGS. 9 and 10 , a solid-state image sensor  14  is mounted on a substrate  12  and covered with a glass lid  16 . The glass lid  16  is fixed onto the solid-state image sensor  14  with a bonding agent  18 . Terminals provided in a circumferential edge portion of the solid-state image sensor  14  are electrically connected through wires  20  to terminals provided in a circumferential edge portion of the substrate  12 . The wires  20  are encapsulated with a sealing resin  22  (Patent Document 1). Solder bumps (not shown) or the like serving as external connection terminals are provided on a lower side of the substrate  12 . 
       PRIOR TECHNICAL DOCUMENT 
     Patent Document 
       [0000]    
       
         [Patent Document 1] JP-A-2007-141957 
       
     
         [0005]    The sealing resin  22  in the solid-state image sensing device  10  is formed by potting or by resin molding with a mold. 
         [0006]    Although the sealing resin  22  is provided for encapsulating the wires  20  or covering a side surface of the glass lid  16 , it is however impossible to avoid occurrence of a so-called bleed phenomenon in which the sealing resin  22  climbs up onto a circumferential edge portion of a front surface of the glass lid  16  when the sealing resin  22  is formed by potting. 
         [0007]    On the other hand, when the sealing resin is formed by resin molding with a mold, extremely high accuracy is required in the height of an assembly  26  to be installed in the mold. The assembly  26  is made of the substrate  12 , the solid-state image sensor  14  and the glass lid  16 . That is, when the height of the assembly  26  is lower than a set height, a gap appears between a surface of a cavity formed in the mold and the front surface of the glass lid  16 . Thus, it is impossible to avoid a so-called flash phenomenon in which the sealing resin  22  flows onto the front surface of the glass lid  16  to form a resin burr  24  thereon ( FIG. 11 ). On the contrary, when the height of the assembly  26  is higher than the set height, the glass lid  16  abuts against an inner wall surface of the cavity. Thus, there is a problem that the glass lid  16  is cracked due to pressure applied thereto from the inner wall surface of the cavity. The total height of the assembly  26  is about 1.1 to 1.2 mm. Therefore, it is impossible to avoid occurrence of any one of the problems due to a variation in the total height of the assembly  26  caused by dimensional variations among the substrate  12 , the solid-state image sensor  14  and the glass lid  16 . 
       SUMMARY 
       [0008]    Exemplary embodiments of the present invention provide a method for manufacturing a solid-state image sensing device and the solid-state image sensing device, which can effectively prevent a sealing resin from producing a bleed phenomenon or a flash phenomenon on a front surface of a glass lid, and also can prevent the glass lid from being cracked. 
         [0009]    A method for manufacturing a solid-state image sensing device, according to an exemplary embodiment of the invention comprises: 
         [0010]    mounting a solid-state image sensor on a substrate; 
         [0011]    forming an elastic layer on a first surface of a glass lid; 
         [0012]    fixing the glass lid onto the solid-state image sensor with a bonding agent so that the glass lid covers the solid-state image sensor while a second surface opposite to the first surface of the glass lid faces the solid-state image sensor; 
         [0013]    electrically connecting a terminal provided on the solid-state image sensor, to a terminal provided on the substrate, through a wire; and 
         [0014]    encapsulating the wire and covering a side surface of the glass lid with a resin. 
         [0015]    The forming the elastic layer on the glass lid may include forming a frame-like elastic layer on a circumferential edge portion of the first surface of the glass lid. 
         [0016]    The forming the frame-like elastic layer on the glass lid may include forming a plurality of frame-like elastic layers on a glass plate with a gap between adjacent ones of the frame-like elastic layers, and cutting the glass plate along the gap and separating the glass plate into individual glass lids. 
         [0017]    The cutting the glass plate may include cutting the glass plate along the gap so that a step portion which is not covered with the frame-like elastic layer is formed in an outermost circumferential edge portion of the first surface of the glass lid, and in the encapsulating and covering with the resin, the step portion may be covered with the resin. 
         [0018]    The elastic layer may be formed by applying a light curable resin onto a glass plate, and exposing the light curable resin to light and developing it. 
         [0019]    The encapsulating and covering with the resin may include performing a resin molding using a mold. Alternatively, the encapsulating and covering with the resin may include potting the resin. 
         [0020]    A solid-state image sensing device according to an exemplary embodiment of the invention comprises: 
         [0021]    a substrate; 
         [0022]    a solid-state image sensor which is mounted on the substrate; 
         [0023]    a glass lid which is fixed onto the solid-state image sensor with a bonding agent so that the glass lid covers the solid-state image sensor while a lower surface of the glass lid faces the solid-state image sensor; 
         [0024]    a wire which electrically connects a terminal provided in a circumferential edge portion of the solid-state image sensor with a terminal provided in a circumferential edge portion of the substrate; and 
         [0025]    a resin which encapsulates the wire, and covers a side surface of the glass lid and a circumferential edge portion of an upper surface of the glass lid. 
         [0026]    The solid-state image sensing device may further comprise: 
         [0027]    a frame-like elastic layer formed inside the resin on the circumferential edge portion of the upper surface of the glass lid. 
         [0028]    According to the exemplary embodiments, it is possible to effectively prevent a sealing resin from producing a bleed phenomenon or a flash phenomenon on a front surface of a glass lid, and it is also possible to prevent the glass lid from being cracked. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0029]      FIG. 1  is a view showing a state where frame-like elastic layers are formed on a large-sized glass plate. 
           [0030]      FIG. 2  is a view showing a state where the large-sized glass plate is cut into individual glass lids. 
           [0031]      FIG. 3  is a plan view showing an individual glass lid. 
           [0032]      FIG. 4  is a front view showing the individual glass lid. 
           [0033]      FIG. 5  is a sectional view showing an assembly. 
           [0034]      FIG. 6  is a view showing a state where the assembly is disposed in a molding mold. 
           [0035]      FIG. 7  is a sectional view showing a solid-state image sensing device. 
           [0036]      FIG. 8  is a plan view showing the solid-state image sensing device. 
           [0037]      FIG. 9  is a view showing an assembly in a solid-state image sensing device according to a related art. 
           [0038]      FIG. 10  is a sectional view showing an example of the solid-state image sensing device according to the related art. 
           [0039]      FIG. 11  is a view showing an example in which a flash phenomenon of a resin burr has occurred on a glass lid. 
       
    
    
     DETAILED DESCRIPTION 
       [0040]    An exemplary embodiment of the invention will be described below in detail with reference to the accompanying drawings. 
         [0041]      FIGS. 1 to 4  are views for explaining steps of manufacturing a glass lid  16 . 
         [0042]    First, as shown in  FIG. 1 , a glass plate  30  is prepared. The glass plate  30  has a size large enough to form a plurality (sixteen in the example of  FIG. 1 ) of glass lids  16 . Each glass lid  16  to be manufactured is about 6 to 7 mm square. A thickness of each glass lid  16  to be manufactured is about 0.4 mm. 
         [0043]    A light curable resin such as an ultraviolet curable epoxy resin is applied on the whole surface of the glass plate  30 , and exposed to light through a desired mask (not shown). Then, the light curable resin is developed so that frame-like elastic layers  32  are formed in circumferential edge portions of regions which will serve as individual glass lids  16  (photolithography step). A resin which has desired elasticity and heat resistance is used as the light curable resin. 
         [0044]    When the frame-like elastic layers  32  are produced, a gap  34  of a desired distance (for example, about 0.4 mm) may be formed between adjacent ones of the frame-like elastic layers  32 . 
         [0045]    Each frame-like elastic layer  32  is formed to be about 0.10 to 0.15 mm thick and about 0.3 to 0.5 mm wide. 
         [0046]    A dicing tape  36  is pasted to a rear surface side of the glass plate  30  opposite to the front surface where the frame-like elastic layers  32  have been formed. The glass plate  30  is cut along the gap  34  by a dice  38  ( FIG. 2 ) and separated into individual glass lids  16  ( FIGS. 3 and 4 ). 
         [0047]    When the width of the gap  34  between adjacent ones of the frame-like elastic layers  32  is made larger than the width of cutting with the dice  38 , a step portion  40  which is not covered with any frame-like elastic layer  32  can be formed in the outermost circumferential edge portion of each glass lid  16 . The step portion  40  has, for example, about 0.1 mm wide. 
         [0048]    Provision of the gap  34  may not be necessary. An elastic layer having a plurality of openings corresponding to the regions which will serve as individual glass lids  16  and the glass plate  30  may be cut simultaneously by the dice  38  and separated into individual frame-like elastic layers  32  and glass lids  16 . However, when the elastic layer and the glass plate which are made of different materials respectively are cut by the dice  38  at the same time, there is a fear that a cutting burr may be produced in the elastic layer or a very small crack may be produced in an edge portion of the glass lid according to the cutting conditions. It is therefore preferable that a gap  34  with a desired width is provided between adjacent ones of the frame-like elastic layers  32  so that only the glass plate can be cut. In addition, when the step portion  40  is formed, there is another merit that a sealing resin can be put on the step portion  40  so as to produce an anchor effect, as will be described later. 
         [0049]    In the embodiment, a light curable resin is applied on the whole surface of the glass plate  30  so that the frame-like elastic layers  32  are formed by the photolithography step. However, a light curable resin film may be bonded and fixed to the glass plate  30 , for example, by thermal compression bonding. 
         [0050]    Alternatively, frame-like elastic layers  32  may be formed in such a manner that the frame-like elastic layers  32  formed into frame-like shapes in advance are bonded to the glass plate  30  by thermal compression bonding. 
         [0051]    In addition, thickness, width, etc. of each frame-like elastic layer  32  are not limited to the aforementioned numeric values. 
         [0052]    Next, description will be made on a method for manufacturing the solid-state image sensing device  10  using the glass lid  16 . As shown in  FIG. 5 , a solid-state image sensor  14  is fixed onto a substrate  12  with a suitable bonding agent. The substrate  12  has a size larger than the solid-state image sensor  14 . In the substrate  12 , terminals (not shown) are formed in a portion exposed outside the solid-state image sensor  14 . 
         [0053]    Then, the glass lid  16  including the frame-like elastic layer  32  is fixed onto the solid-state image sensor  14  with an ultraviolet curable bonding agent  18  so that the solid-state image sensor  14  is covered with the glass lid  16  while the frame-like elastic layer  32  faces outside (upward) (in other words, a lower surface of the glass lid  16 , which is opposite to an upper surface where the frame-like elastic layer  32  is formed, faces the solid-state image sensor  14 ). A desired space is formed between the solid-state image sensor  14  and the glass lid  16  with the bonding agent  18  serving as a spacer. 
         [0054]    The solid-state image sensor  14  has a size larger than the glass lid  16 . In the solid-state image sensor  14 , terminals (not shown) are formed in a portion exposed outside the glass lid  16 . 
         [0055]    Then, the terminals of the solid-state image sensor  14  and the terminals of the substrate  12  are electrically connected through wires  20 . Thus, an assembly  26  is formed. 
         [0056]    As shown in  FIG. 6 , the assembly  26  is disposed between upper and lower molds  42  and  44  of a transfer molding machine (not shown). 
         [0057]    Only one assembly is shown as the assembly  26  in  FIG. 5 . However, a substrate sheet  48  in which a plurality of substrates are built up in a form of a matrix is used in fact. Assemblies  26  in each of which the solid-state image sensor  14  and the glass lid  16  are installed on each of the substrates  12  of the substrate sheet  48  are used. The assemblies  26  are disposed between the upper and lower molds  42  and  44 . For the sake of simplification of the drawing, not all the assemblies but only one assembly  26  is shown in  FIG. 6 . A desired cavity  46  for encapsulating the wires  20  with a resin is formed in the upper and lower molds  42  and  44 . 
         [0058]    Then, the upper and lower molds  42  and  44  are closed. 
         [0059]    When the molds are closed, an inner wall surface of the cavity  46  abuts against the frame-like elastic layer  32  because the frame-like elastic layer  32  with a desired thickness has been formed on a front surface of the glass lid  16 . Thus, the molds are closed with pressure applied to the frame-like elastic layer  32 . 
         [0060]    In manufacturing, some variation inevitably appears in each thickness of the substrate  12 , the solid-state image sensor  14 , the bonding agent  18  and the glass lid  16 . The thickness of the frame-like elastic layer  32  is set to absorb such a variation of thickness on the assembly  26  side. 
         [0061]    Then, a sealing resin which is melted is injected into the cavity so that the wires  20  are encapsulated with the resin. 
         [0062]    As described above, the inner wall surface of the cavity  46  and the frame-like elastic layer  32  are brought into tight contact without any gap when the molds are closed. Thus, when the melted sealing resin is injected into the cavity, the melted sealing resin does not enter the gap so that the flash phenomenon (resin burr) can be effectively prevented from occurring. In addition, the inner wall surface of the cavity comes into gentle contact with the glass lid  16  through the frame-like elastic layer  32 . Thus, there is no such problem as in the related art that the inner wall surface of the cavity comes into direct contact with the glass lid  16  to crack the glass lid  16  when the height of the assembly  26  is higher than a set height. 
         [0063]    Whether the height of the assembly  26  is lower or higher than the set height, the frame-like elastic layer  32  can absorb the variation of the height. 
         [0064]    After the resin molding, the molds are opened and the assemblies  26  are extracted from the molds. External connection terminals (not shown) such as solder bumps are attached onto the predetermined terminals of each assembly on a lower side of the substrate sheet  48 . The substrate sheet  48  is cut and separated into individual substrates  12 . Thus, individual solid-state image sensing devices  10  are completed. 
         [0065]    Incidentally, the reference numeral  50  represents a release film which makes it possible to separate molded pieces from the molds easily. The release film  50  does not have to be always used. 
         [0066]    The sealing resin  22  is formed by resin molding with a mold in the embodiment. However, in the case where the sealing resin  22  is formed by potting, the frame-like elastic layer  32  serves as a dam to prevent the potting resin from climbing up onto the front surface of the glass lid  16 . Thus, the bleed phenomenon can be effectively prevented from occurring. 
         [0067]    When the step portion  40  is produced in the outermost circumferential edge of the glass lid  16  as described above, the step portion  40  is filled with a molding resin or a potting resin so as to press the edge portion of the glass lid  16  from above. Thus, the anchor effect of the glass lid  16  occurs. In addition, the edge portion of the glass lid  16  is perfectly covered by the resin. Therefore, even if a very small crack appears in the edge portion, such a problem that a very small chip adheres to the front surface of the glass lid  16  can be solved. 
         [0068]    Incidentally, the concept of the glass lid  16  may include not only so-called glass but also a wide variety of transparent members. 
         [0069]    In addition, the frame-like elastic layer  32  may be left on the glass lid  16  as it is, or may be removed from the glass lid  16 . 
         [0070]    While the invention has been described with respect to a limited number of embodiments, those skilled in the art, having benefit of this disclosure, will appreciate that other embodiments can be devised which do not depart from the scope of the invention as disclosed herein. Accordingly, the scope of the invention should be limited only by the attached claims.