Abstract:
The present disclosure is directed to a camera module that includes at least a semiconducting die, an image-sensing circuit, a lens, a lens aperture, and a coating that adheres to an exterior surface of the camera module. The coating is opaque to light and prevents light from accessing the camera other than through the lens aperture. The opaque coating is applied as a fluid and is cured. In one embodiment, a mask material is selectively applied to exterior surfaces of the semiconducting die, electrical interconnect layers, glass layers, the lens body, or the lens aperture. After applying the opaque coating, the selectively applied mask material is removed. Methods of selectively applying a mask material include applying a conformable and peelably releasable dope-like material, placing an array of joined, selectively shaped rigid masks over an array of assemblies, and applying a conformable mask material that is heat-expandable.

Description:
BACKGROUND 
       [0001]    1. Technical Field 
         [0002]    This present disclosure generally relates to light sensitive electronic devices and, in particular, to a method and system of shielding electronic devices from light. 
         [0003]    2. Description of the Related Art 
         [0004]    Advances in the field of semiconductor wafer-level manufacturing have enabled wafer-level processing techniques to be applied to the manufacture of optical lenses and to bump thru-silicon via (TSV) sensor technology. One application of these advances is in the manufacture of a new generation of camera modules. Although camera modules produced by these new processes have the benefit of being compact in size, many do not effectively prevent stray light from entering the camera lens. Stray light that enters the camera modules through sidewalls negatively impacts image quality. Techniques exist in the art for preventing stray light from entering the camera module, however each has the negative consequences of raising the cost of the camera module or increasing the overall size of the camera module, or both. 
         [0005]    For example,  FIGS. 1A and 1B  show a known plastic molded lens housing  10  configured to be arranged over a sensor module (not shown). The molded lens housing  10  includes a lens stack  12  that extends from an opening  18  in a back surface  20  to an opening  22  in a front surface  24 . The opening  22  in the front surface  24  allows an image to be sensed by the sensor module when assembled with the housing  10 . The sensor module may be on a rectangular substrate that is configured to fit within the opening  18 . The molded lens housing  10  is thick black plastic that absorbs light and acts as the primary light shield of the camera module. A thickness  14  of walls  16  increases the overall size of final camera module and is limited by manufacturing constraints of molded plastic. The molded lens housing  10  is manufactured separately and then attached to the sensor module in a subsequent step. Additionally, if the molded lens housing  10  is used with a TSV die, careful design is required to ensure that the molded lens housing  10  fully covers the TSV die to prevent stray light from entering the camera module at an edge. 
         [0006]      FIG. 2  is a cross-sectional view of a camera module  26  having a thin metal shield can  28  positioned on top and side surfaces  36  and  38 . The camera module  26  includes an optical lens  27  having semi-transparent sidewalls  29 . The camera module  26  is formed on a top surface  31  of a TSV die  30  that extends wider than the semi-transparent sidewalls  29 . The shield can  28  is manufactured as a separate component from the optical lens  27  and attached with glue  32  on the top surface  36 . The camera module  26  is then heated in an oven to cure the glue  32  and secure the shield can  28  on the camera module  26 . 
         [0007]    The shield can  28  extends down to a bottom surface  33  of the TSV  30  to seal the camera module  26  and optical lens  27  from light. Misalignment of the shield can  28  can allow light into the camera module  27 . Also, an air gap  34  extends between side surfaces  38  of the semi-transparent sidewalls  29  and the shield can  28 . The shield can  28  can be 100 microns in thickness, which with the air gap  34  makes the overall device larger in size. The shield can  28  increases a width of the camera module  26  by more than 0.5 millimeters. The manufacturing and assembly of the shield can  28  are expensive and increase the camera module&#39;s overall size. 
         [0008]      FIG. 3  is a known camera module  40  that uses precut sheets of high-temperature black paper  39  adhered to outer walls  44  of the camera module  40 . The black paper  39  is coated with a high-temperature adhesive on one side that securely attached the paper  39  to the outer walls  44 . The walls  44  of the camera module  40  are substantially similar in width to the TSV die  30 . If there are variations between the width of the walls and the die  30 , the paper  39  is difficult to align accurately, which complicates automating the method. The paper  39  is also unreliable in its adhesion to the sides of the camera module. The paper is easily scratched, which allows stray light to interfere with the lens. Accordingly, this method is expensive to implement and cycle times are higher than for other light shielding assemblies. 
       BRIEF SUMMARY 
       [0009]    According to one embodiment of the present disclosure, an apparatus includes a semiconducting die having an image-sensing circuit, a die interface layer, an electrical interconnect layer, a glass layer, a lens body, a lens aperture, and an ink coating. The lens body is on a first surface of the semiconducting die and the die interface layer lies on a second surface, opposite to the first surface, of the semiconducting die. The electrical interconnect layer electrically couples to the image-sensing circuit through the die interface layer. The lens body is on the glass layer and has an aperture on an end away from the glass layer through which the lens body receives an image. An ink coating adheres to sidewalls of the lens body and the glass layer to prevent stray light from entering the lens body. 
         [0010]    In one embodiment, prior to applying the ink coating a mask material is selectively applied to an exterior surface (i.e., the interface layer, the electrical interconnect layer, the glass layer, the lens body, the lens aperture, or to more than one). The mask material is configured to be removable after application of the ink. For example, the mask material may be placed over the lens aperture to prevent ink from coating the lens aperture. The die interface layer would be protected because it would be facing a surface or carrier on which the apparatus was positioned. The ink is an opaque coating in liquid or aerosol form that is applied to all exposed surfaces of the apparatus. The ink coating can be cured and then the selectively applied mask material can be removed. 
         [0011]    In one embodiment selectively applying a mask material includes applying a conformable and peelably releasable putty-like material. In another embodiment, the selectively applying a mask material includes placing an array of joined, selectively shaped rigid masks over an array of the apparatuses. In yet another embodiment, the selectively applying a mask material includes applying a conformable mask material that is heat-expandable. 
         [0012]    According to another embodiment of the disclosure, a color-contrasted electronic package includes a semiconductor die, an encapsulation material, an electromagnetic interference (EMI) shield layer, a selectively colored ink, and a marking material. The encapsulation material surrounds the semiconductor die on at least several sides. The EMI shield layer adheres to an exterior surface of either the semiconductor die or the encapsulation material, or both. The selectively colored ink adheres to the exterior surface of the EMI shield layer, and the marking material lies on the selectively colored ink. In one embodiment the marking material and the selectively colored ink have contrasting colors. In another embodiment, a portion of the adhered selectively colored ink is removed from the exterior surface of the EMI shield layer, the selectively colored ink and the EMI shield layer having contrasting colors. 
         [0013]    The black ink coated light shield has the advantages of maintaining the size of the apparatus or module to which the shield is providing protection, adding little to the overall cost of the apparatus or module, and in production is a scalable process that does not affect the cycle time or production rates of apparatus or modules to which the light shield is applied. 
     
    
     
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS 
         [0014]      FIG. 1A  shows a bottom isometric view of a known molded lens housing for shielding a camera module from light. 
           [0015]      FIG. 1B  shows a top isometric view of the known molded lens housing of  FIG. 1A . 
           [0016]      FIG. 2  shows a partial cross-sectional view of a known shield can over a camera module. 
           [0017]      FIG. 3  shows an isometric view of a camera module with a precut black paper light shield on exterior walls. 
           [0018]      FIG. 4A  shows a top isometric view of a camera module having a coated light shield in accordance with one embodiment of the present disclosure. 
           [0019]      FIG. 4B  shows a bottom isometric view of a camera module having a coated light shield in accordance with one embodiment of the present disclosure. 
           [0020]      FIG. 5  is an isometric view a camera module prior to coating in accordance with one embodiment of the disclosure. 
           [0021]      FIG. 6  is a simplified cross-sectional view of the camera module taken through  6 - 6  of  FIG. 5  in accordance with one embodiment of the disclosure. 
           [0022]      FIG. 7A  is a simplified cross-sectional view of a camera module having a peelable masking material on a first surface in accordance an embodiment of the present disclosure. 
           [0023]      FIG. 7B  is a simplified cross-sectional view of a camera module having a peelable masking material on a second surface in accordance with an embodiment of the present disclosure. 
           [0024]      FIGS. 8A and 8B  show perspective views of a camera module without and with a metal mask, respectively, in accordance with one step of a method of one embodiment of the present disclosure. 
           [0025]      FIG. 8C  is a metal mask having an array of heads in accordance with an embodiment of the present disclosure. 
           [0026]      FIG. 9  shows an isometric view of a heat-expandable mask on a camera module in accordance with an embodiment of the present disclosure. 
           [0027]      FIGS. 10A ,  10 B are schematic views of a process of applying a light shield to a plurality of camera modules in accordance with one embodiment of the present disclosure. 
           [0028]      FIG. 11  is an alternative process of applying a light shield to a plurality of camera modules, in accordance with another embodiment of the present disclosure. 
           [0029]      FIGS. 12A and 12B  show isometric views an array of camera modules before and after coating with a black ink, respectively, in accordance with one embodiment of the present disclosure. 
           [0030]      FIG. 13  shows an isometric view of a masked camera module after coating with black ink in accordance with yet another embodiment of the present disclosure. 
           [0031]      FIG. 14  is a top down view of an electronic module array having an electromagnetic interference shield layer in accordance with one embodiment of the disclosure. 
           [0032]      FIG. 15  shows a side, cut-away view of the electronic module array taken along  15 - 15  of  FIG. 14  prior to coating with an electromagnetic interference shield. 
           [0033]      FIG. 16  shows a schematic view of the electronic module of  FIG. 15  being coated with an electromagnetic interference shield. 
           [0034]      FIG. 17  is a side view of an array of electronic modules after coating with black ink in accordance with one embodiment of the present disclosure. 
       
    
    
     DETAILED DESCRIPTION 
       [0035]      FIGS. 4A and 4B  are top and bottom isometric views, respectively, of a camera module  50  in accordance with an embodiment of the present disclosure. The camera module  50  includes top and bottom surfaces  52 ,  54  and sidewalls  56 . Within the camera module  50  is a lens  58  evident through a lens aperture  60  in the top surface  52 . The lens  58  is placed on a stack of a plurality of layers  80  of semi-transparent material, see  FIG. 5 . The stack of layers  80  are positioned on a TSV glass layer (not shown in  FIGS. 4A-4B ) positioned on a top surface of a substrate  62  that includes an electronic sensor (not shown). The substrate  62  may be a silicon wafer. The sensor in the substrate  62  is optically coupled through the TSV glass layer to the lens  58  and is configured to process images received through the lens. The substrate  62  also has a bottom surface that is the bottom surface  54  of the camera module  50  in one embodiment. 
         [0036]    The camera module  50  also has a plurality of solder balls  64  arranged in a ball grid array on the bottom surface  54  of the camera module  50 . The plurality of solder balls  64  are electrically connected to contacts of the sensor positioned in the substrate  62 . The ball grid array provides an electrical connection between the camera module  50  and a circuit board of an electronic device, such as a cell phone, a digital camera, or laptop. Other forms of electrical interconnection between the sensor and the circuit board may be used. 
         [0037]    The sidewalls  56  are formed of semi-transparent material that would allow light into the camera module  50  if they were not covered. In order to prevent unwanted light from being detected by the sensor, the sidewalls are coated with ink  70 . The ink  70  is a dark color, such as black, that absorbs all frequencies of light, thereby allowing no light to enter the camera module. In one embodiment, the ink  70  is a high temperature epoxy-type black ink, although those skilled in the art will understand that various other inks could be employed to shield light from passing through the sidewalls  56 . The ink  70  coats the sidewalls  56  of the camera module, but does not coat the top and bottom surfaces  52 ,  54  of the camera module  50 . By selecting only the sidewalls  56  for coverage, the ink  70  coated to be shield light does not interfere with the lens  58 or with the substrate  62 . Selective coating of the ink  70  on the camera module  50  is accomplished using masking, as will be discussed below. Embodiments having various arrangements of the dark ink on various surfaces of the camera module are all considered within the scope of the present disclosure. 
         [0038]      FIG. 5  is a three-dimensional view of a camera module  72  prior to being coated with the ink  70 . The camera module  72  includes a lens body  73  with a top surface  74  having a lens aperture  76 . The camera module also includes an optical lens  78  formed within the lens body  73  and underlying the lens aperture. The lens body  73  includes a plurality  80  of layers formed on a TSV glass layer  82  on a semiconductor die  84 . The plurality  80  of layers includes a stack of semi-transparent material layers  86  formed using semiconductor processing techniques to surround the optical lens  78 . A top layer or baffle  88  of the plurality  80  of layers is an opaque material through which the lens aperture  76  extends. The opaque baffle  88  prevents unwanted light from entering the optical lens  78  through the top of the camera module, other than through the lens aperture  76 . The opaque baffle  88  is simple to form on the top of the camera module  72  and works with the ink  70  to be formed as a light shield on sidewalls  90  of the optical lens  78 . 
         [0039]      FIG. 6  is a simplified cross-sectional view of the camera module  72  of  FIG. 5  taken through  6 - 6 . The optical lens  78  is formed within the plurality of layers  80 , which include the semi-transparent layers  86  (see  FIG. 5 ) and the top opaque layer  88 . The lens aperture  76  is formed through the opaque layer  88  to allow light into the optical lens  78 . A focus member  92  may be included to direct the light into the optical lens  78 . The camera module  72  includes the TSV glass layer  82  on the die  84 . The sidewalls  90  of the plurality of layers  80  do not extend to an edge  94  of the TSV glass layer  82 . However, in alternative embodiments, especially where a second surface  96  is positioned upward during application of the ink  70 , the sidewalls  90  may extend to the edge  94 . 
         [0040]    A ball grid array  98  is formed on the second surface  96  of the die  84 . The ball grid array  98  provides electrical connection from contacts on the die  84  to the electronic device in which the camera module  72  will be installed. 
         [0041]      FIGS. 7A and 7B  are alternative methods of coating a pair of the camera modules  72  with ink  70  to form a thin light shield. In one embodiment of the method, the first or second surfaces  74  and  96 , respectively of the camera modules  72  are covered with a masking material  100 . In  FIG. 7A , the masking material  100  shields the lens  78 , the lens aperture  76 , and the first surface  74  from the ink  70  as it is applied to the sidewalls  90  of the optical lens  78 . The ink  70  will also coat exposed portions of the TSV glass layer  82  and the die  84 , which may include a top surface of the TSV glass layer  82  and side surfaces of the TSV glass layer and the die. The sidewalls  90  of the optical lens  78  and the side surfaces of the TSV glass layer  82  and the die  84  form exterior walls of the camera module  72 . As in  FIG. 7B , the ball grid array  98  is shielded from the black ink  70  coating applied during the method of forming the thin light shield. In other embodiments of the method, alternative surfaces or regions of surfaces of the camera module  72 , or other kinds of electronic modules, are masked. All of these embodiments are considered within the scope of the disclosure. Methods of coating the sidewalls  90  will be described in more detail below. 
         [0042]    In  FIG. 7A , the camera modules  72  are positioned on a carrier  102  with the second surface  96  facing the carrier. The modules  72  are spaced from each other by a distance that allows the ink  70  to sufficiently coat the sidewalls  90 . The carrier  102  acts as a support or stiffener to transport the camera modules  72  as they are covered with ink  70 . As described above with respect to  FIG. 6 , the TSV glass layer  82  and die  84  are wider than the optical lens  78  and the sidewalls  90 . In  FIG. 7B , the camera modules  72  are positioned on the carrier  102  with the first surface  74  facing the carrier. Also, the TSV glass layer  82  and the die  84  are as wide as the sidewalls  90  of the optical lens  78 . When the first surface  74  is facing the carrier  102 , the TSV glass layer  82  and the die  84  are equal to or smaller than the sidewalls  90  of the optical lens so that the TSV glass layer  82  and the die  84  do not interfere with the application of the ink  70 . Forming the TSV glass layer  82  and the die  84  to be at most as wide as the sidewalls  90  ensures that all of the sidewalls  90  are fully coated with ink  70 . 
         [0043]    In both  FIGS. 7A and 7B , the masking material  100  is a peelable, pliable, putty-like material that is applied by hand or machine over the first or second surface  74 ,  96  of the camera module  72 . Due to the putty-like consistency of the material, the peelable masking material  100  can be applied to the first and second surfaces  74 ,  96  at a thickness sufficient to cover vertical features, such as the ball grid array  98 , and uneven surfaces such as the lens aperture  76 . Conversely, if the surface being covered is smooth, the peelable masking material  100  can be made thin. The peelable masking material  100  is configured to be easily released from the first and second surfaces  74 ,  96  without leaving residue after the peelable masking material  100  is removed. 
         [0044]    In an alternate embodiment for masking shown in  FIGS. 8A-8C , the first or second surface  74 ,  96  of the camera module  72  is covered by a reusable metal mask  104 . In  FIG. 8A , the camera module  72  is positioned so that the second surface  96  having the ball grid array  98  is exposed. The die  84  is not as wide as the sidewalls  90 . This allows all the sidewalls  90  to be coated with the ink  70 .  FIG. 8B  the camera module  72  having the second surface  96  covered by a head  106  of the metal mask  104 . The head  106  is attached to a frame  108  and is configured to cover the entire second surface  96  of the camera module  72 . 
         [0045]    In  FIG. 8C , the metal mask  104  has an array of heads  106  attached to the frame  108  of the metal mask  104 . The array of heads  106  are fixed at regular intervals in the metal mask  104  by the frame  108 . The array of heads  106  in  FIG. 8C  includes  4  subarrays of five by four heads. The array has the heads  106  positioned in a diamond arrangement, although other suitable positions are also acceptable. Accordingly, eighty camera modules  72  could be coated with ink  70  simultaneously. The camera modules may be positioned on the carrier  102  so that the metal mask  104  can be positioned over the second surface  96  of the camera modules  72 . The array of heads  106  is placed over the plurality of the camera modules  72 , so that each head  106  coincides with the first or second surface  74  or  96  of the camera module  72  to be masked. Once the camera modules are coated with ink  70 , the mask  104  is easily removed from all of the camera modules simultaneously. 
         [0046]    In  FIG. 9 , in yet another embodiment for masking the camera module  72 , the top surface  74  of the camera module  72  is masked by a heat-expandable mask  109 . Of course, the mask  109  could also be employed to mask the bottom surface  96  of the camera module  72 . The heat expandable mask  109  is composed of a pliable putty-like thermally responsive material that is applied by hand or machine over the top surface of the camera module  72 . Due to the putty-like consistency of the material, the heat-expandable mask  109  can be applied to surfaces at a thickness sufficient to cover vertical features, such the ball grid array  98 , and uneven surfaces, such as the top surface  74  with the lens aperture  76 . In one embodiment, the heat-expandable masking material  109  is in the range of 5 and 500 microns in thickness. If the surface to be covered is smooth, the heat-expandable mask  109  can be made thin. The material of the heat-expandable mask  109  has the quality of expanding under elevated temperatures, such as between 50 and 200 degrees Celsius, to ease release of the heat-expandable mask  109  from the surface of the camera module  72 . 
         [0047]      FIGS. 10A and 10B  show a part of the method of applying ink to coat a plurality of camera modules  72 . In  FIG. 10A , the first surfaces  74  of the camera modules  72  are covered with the masking material  100  as the ball grid arrays  98  rest on the carrier  102 . A spray gun  110  is positioned above the carrier  102  and the camera modules  72  and is configured to spray a high-temperature resistant epoxy based black ink  70  to coat the sidewalls  90  and the exposed portions of the TSV glass layer  82 . The ink  70  may be an atomized spray from the spray gun  110 . The ink  70  is coated to be in a thickness in the range of 5 to 200 microns. The ink  70  is also configured to withstand the temperatures reaches for solder reflow. 
         [0048]    The spray gun  110  is configured to move in three dimensions, i.e., a height of the spray gun  110  from the masking material  100  can be adjusted and the spray gun  110  can move forward, backward, left, and right over the camera modules  72  to achieve even coverage of the sidewalls  90  of the plurality of camera modules  72 . The spray gun  110  may be configured to move along other angles in a variety of directions. A rate at which the ink  70  is expelled from the spray gun  110  can be adjusted. A viscosity of the ink  70  is selected to sufficiently coat the sidewalls  90  of the camera modules  72  while avoiding spotty or uneven coverage. 
         [0049]    In  FIG. 10B , the second surface  96  of the camera module  72  is covered with the masking material  100 . The TSV glass layer  82  and the die  84  (not shown) are as wide as the sidewalls  90 . This equal width allows the ink  70  to coat the portions of the sidewalls  90  adjacent the TSV glass layer  82 . In  FIGS. 10A and 10B , the peelable masking material  100  is used, but the metal mask  104 , the heat-expandable mask  109 , or other suitable masking materials are also within the scope of the disclosure. 
         [0050]      FIG. 11  is a alternative embodiment of the spray gun  110  configured to apply ink  70  with the spray gun  110  inclined at an angle. In one embodiment, the spray gun  110  is angled between 20 degrees and 70 degrees with respect to the top surface  74  of the camera module  72 . The inclined spraying can coat the sidewalls  90  of the camera module  72  are more evenly. In order to fully coat the sidewalls  90 , the spray gun&#39;s  110  angle can be adjusted throughout the process. 
         [0051]      FIG. 12A  is a simplified three-dimensional view of a plurality of camera modules  72  on the carrier  102 , positioned to be coated with ink  70  in bulk. The masking material  100  may be formed on the camera modules  72  by an automated distribution process. The first or second surface of the camera module is exposed and then covered with the masking material  100 . The carrier  102  is placed in an ink spraying chamber where the spray gun  110  passes over each of the camera modules to spray ink  70  on the sidewalls  90 . After the camera modules  72  are coated with ink  70 , the carrier  102  may be placed in an oven to cure the ink  70 . 
         [0052]      FIG. 12B  are the plurality of camera modules  72  after the ink  70  has been applied and cured. The ink  70  coats all exposed surfaces. Subsequently, the masking material  100  is removed from the first or second surface of the camera modules  72 . The ink  70  is a dark color that prevents light from interacting with the lens  78  through the plurality of transparent layers  80 . Accordingly, the camera modules  72  have a very thin light shield that does not appreciably increase the size of the camera module. 
         [0053]    In  FIG. 13 , the heat-expandable mask  109  is used, which increases in size as the ink  70  is cured. The heat-expandable mask  109  expands under elevated temperature during curing, which causes the mask  109  to separate from the camera module  72  as it expands. The expansion of the heat-expandable masking material  109  eases the removal of the masking material from the camera module  72 . 
         [0054]      FIG. 14  is a top down view of an electronic module array  112  having an electromagnetic interference shield formed according to another embodiment of the present disclosure. A plurality of electronic modules  114  are positioned at intervals in the array  112 . Each electronic module  114  includes a die  116  that is coupled to a ball grid array  118  and covered with a molding compound  120 , see  FIG. 15 . The electronic module may be have an embedded wafer level ball grid array. A groove  122  separates adjacent electronic modules  114 . In an alternative embodiment, the electronic module array  112  may be a plurality of camera modules  72  as described above. The electronic module array  112  may be coated with ink  70 . 
         [0055]      FIG. 15  is a cross-sectional view of the array  112  of electronic modules  114  taken through  15 - 15  of  FIG. 14 . Each electronic module has the die  116  positioned on a frame or substrate  124  onto which solder balls of the ball grid array  118  are coupled. Each die  116  is covered with the molding compound  120  and separated from an adjacent die  116  by molding compound  120  and the groove  122 . After processing, a laser, saw, or water jet cutting device will singulate the electronic modules  114  by cutting through the groove  122 . The molding compound  120  may be covered in ink if stray light is a concern. 
         [0056]      FIG. 16  is the array  112  of electronic modules  114  being coated with an electromagnetic interference shield  126 . A conductive paint  128  is sprayed from a spray gun  130  to evenly coat a top  132  and sidewalls  134  of the electronic modules  114 . The conductive paint  128  is reflective and in one embodiment includes silver particles, which makes subsequent marking of the electronic module  114  difficult. There is less contrast of the marking on reflective conductive paint  128 . Accordingly, the array  112  of electronic modules  114  having the conductive electromagnetic interference shield  126  can be covered with the ink  70  described above with respect to the camera modules. The ink  70  provides a surface that allows for more contrast when marking. 
         [0057]      FIG. 17  shows the electronic modules  114  having the electromagnetic interference shield  126  covered with the ink  70 . The ink  70  may be applied as described above with respect to  FIGS. 10A ,  10 B, and  11 . The ink  70  may also be cured with heat. By adding the layer of ink  70 , good marking contrast can be achieved. In one embodiment, the ink layer  70  is etched, such as by a chemical etch, to remove the black ink in a pattern of the letters or numbers to be formed. Due to the color contrast between the brightly colored electromagnetic interference shield layer  126  and the ink  70 , removal of portions of the ink causes the marking characters to be prominently visible on the top surface  132  of the electronic module  114 . 
         [0058]    In another embodiment, the marking characters are scribed into the ink  70  by using a laser to remove the ink. The laser removes portions of the ink to reveal the electromagnetic interference shield layer  126  underneath the ink  70 . The revealed electromagnetic interference shield layer  126  contrasts with the dark ink to make the marked characters distinct to the human eye. The electromagnetic interference shield is a silver or gray color, in a strong contrast to the black ink. In another embodiment, the marking characters are placed over the ink  70  using a marking ink having a color that contrasts with the color of the dark ink  70 . 
         [0059]    These and other changes can be made to the embodiments in light of the above-detailed description. In general, in the following claims, the terms used should not be construed to limit the claims to the specific embodiments disclosed in the specification and the claims, but should be construed to include all possible embodiments along with the full scope of equivalents to which such claims are entitled. Accordingly, the claims are not limited by the disclosure.