Patent Publication Number: US-2007108576-A1

Title: Packaging structure of RSMMC memory card

Description:
BACKGROUND OF THE INVENTION  
      1. Field of Invention  
      The present invention relates generally to a packaging structure of memory card package. More particularly, the present invention relates to an improved packaging structure of RSMMC memory card.  
      2. Description of the Related Art  
      The conventional package structure of RSMMC memory card is showed in  FIG. 1  and  FIG. 2 . The package structure comprises an electrical circuit board  10  and a plastic cover  20 . The electrical circuit board  10  further comprises passive devices and various integrated circuit (IC) devices, such as flash IC. A plurality of golden fingers are formed on a back surface of the electrical circuit board  10  and are utilized to electrically connect to other electrical devices. The plastic cover  20  is formed into a L-shaped plastic cover and is utilized to cover the electrical circuit board  10  in order to seal all the IC devices and the passive devices. Therefore, package of RSMMC memory card is formed.  
      The conventional packaging structure of RSMMC memory card must utilize the plastic cover  20  to seal the whole packaging structure. The fabricating process of the plastic cover  20  involving a projecting shaped must be formed so that a space can be formed in between as shown in  FIGS. 1 &amp; 2 . As result the thickness of the plastic cover  20  must be maintained to a required thickness so that the structure is strong enough to subject any pressure. However, when the thickness of the plastic cover  20  is increased to thicken its thickness, the space within the plastic cover is thus reduced. As a result, less IC devices can be located inside the substrate. As a matter fact, most fabricators utilized those expansive, very thin and small in size of IC devices in order to accommodate the limited space within the packaging structure. Thus, the manufacturing cost of the package of the memory card is increased. Furthermore, those expansive IC devices are not reliable, and the cost of the package structure of the RSMMC memory card is thus increased, its competition in the market is therefore reduced.  
     SUMMARY OF INVENTION  
      It is an object of the present invention to provide a packaging structure of a RSMMC memory card. More particularly, the present invention relates to an improved packaging structure of RSMMC memory card. The present invent provide an improved design of packaging structure that has enough space to accommodate different types of IC devices and passive devices can be installed therein. It is another object of the present invention to provide a packaging structure of the RSMMC memory card comprising reliable IC devices and the packaging structure can be fabricated with low cost in order to increase its competition in the market. The packaging structure of the present invention comprises a substrate having a plurality of IC devices and passive devices located therein. A frame integrated with the substrate is surrounded with the IC devices and the passive devices. A metal cover having an insulating layer formed on a top portion of the metal cover. The metal cover is covered the frame and the substrate to form a sealed structure. A plurality of fixed plates bending downward are formed around a circumferential area of the metal cover, and a protruding block and fixing slots are formed on pre-selected protruding plate of the frame. The protruding bock and the fixing slots are utilized to engage the frame onto the metal cover in order to form a RSMMC packaging structure. The IC devices and the passive devices are located within the space of the frame and are protected by the metal cover.  
      Both the foregoing general description and the following detailed description are exemplary and explanatory only and are restrictive of the invention, as claimed. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
      The accompanying drawings are included to provide a further understanding of the present invention, and are incorporated in and constitute a part of this specification. The drawings illustrate embodiments of the invention and, together with the description, serve to explain the principles of the invention. In the drawings,  
       FIG. 1  illustrates a 3-D view of a conventional packaging structure of RSMMC memory card.  
       FIG. 2  shows a partial cross-sectional view of the conventional packaging structure of RSMMC memory card.  
       FIG. 3  is a 3-D assembled view of a packaging structure of RSMMC memory card in accordance with a preferred example of the present invention.  
       FIG. 4  is another 3-D view of a completed assembled structure of a packaging structure of RSMMC memory card in accordance with the preferred example of the present invention.  
       FIG. 5  is a partial cross-sectional view of the assembled structure of the RSMMC memory card in  FIG. 4   
       FIG. 6  is another 3-D view of assembled view of a packaging structure of RSMMC memory card in accordance with a preferred example of the present invention.  
       FIG. 7  is a 3-D view of a coating layer onto a back surface of a substrate of a preferred example of the present invention.  
       FIG. 8  is a partial cross-sectional view of a back surface of the coating layer of the substrate in  FIG. 7 . 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS  
      Refer to  FIG. 3 , the present invention provides a packaging structure of RSMMC memory card, the packaging structure comprises a substrate  1 , a frame  2  and a metal cover  3 . Wherein the substrate  1 , as shown in  FIG. 3 , is a circuit board consisting required circuits formed on its platform. An inner platform  11  comprising various type of integrated circuit (IC) devices  12  that are required by a memory card, such as the control chip device and flash IC chip, as well as other passive devices  13 . A plurality of golden pins  15  are formed on an outer platform  14 . The golden pins  15  are utilized to electrical connect to other electrical products.  
      The frame  2 , as shown in  FIG. 3 , is a square shaped plastic frame for integrating the substrate  1  and is surrounded by the various types of IC devices  12  and the passive devices  13 . A space  21  is formed in a middle portion of the frame  2  and is utilized to locate the devices  12  and the passive devices  13 . At least one L-shaped slot  22  is formed on a pre-selected strip block locating on a circumferential area of the space  21 . The L-shaped slot  22  is utilized to integrate the frame  2  to the metal cover  3 . Four strip-shaped blocks can be formed around the circumferential area of the space  21 , and every strip-shaped block has a L-shaped slot  22 . A protruding block  23  is formed outside a pre-set strip-shaped block and is utilized to integrate with the metal cover  3 .  
      The metal cover  3 , as shown in  FIG. 3 , is utilized to cover the substrate  1  locating on a top surface of the frame  2  so that a sealed thin layer of metal device is formed. This thin layer of metal device is approximately 0.05 mm thick and an insulating layer is formed onto its surface. A plurality of fixed plates  31  are formed around a circumferential area of a bottom portion of the metal cover  3  and are bended downward. A L-shaped protruding plate  32  is formed on one end of the pre-selected fixed plate  31  bended outward. Fixing slots  33  are formed correspondingly to the position of the protruding block  23  along the pre-selected fixed plates  31 .  
      The frame  2  is directly engaged with the metal cover  3  to form a projecting-shaped structure as shown in  FIG. 4  and  FIG. 5 . The L-shaped protruding plate  32  and the fixing slots  33  locating around the metal cover  3  are utilized to engage with the frame  2 . (The protruding portions such as the L-shaped slot  22  and the protruding block  23  are engaged together to form a fixed structure). The substrate  1  is engaged into the gap  22  of the frame  2  so that the metal cover  3  so that the metal cover  3  covers and seals the IC devices  12  and the passive devices  13  locating within the substrate  1 . A coating layer  16  is formed on an outer surface  14  of the substrate  1  to fill up the gap inside the substrate as shown in  FIG. 7  and  FIG. 8 . The golden fingers  15  are separated away from other structures. Thus, a packaging of RSMMC memory card structure is formed.  
      The present invention provides a design of a packaging structure of RSMMC memory card. The frame  2  and the metal cover  3  can be pre-assembled with the substrate  1  to form a sealed structure. The metal cover  3  comprises enough ductile materials that it can form into a very thin layer structure with a thickness approximately 0.05 mm. The present invention provides an improvement on the design of the frame  2  and the metal cover  3  and its assembled structure. The improved design of the RSMMC memory card can be thus increased its spacious size inside the frame  2 , such as the space  21 , in order to locate any various IC devices  12  without failing the thickness requirement of the RSMMC memory card as shown in  FIG. 5 . The IC devices  12  can be control chip device and flash IC chip, as well as other passive devices  13 . The improved packaging structure of RSMMC memory card of the present invention provides enough space  21  within the substrate  1  so that the fabricators or designers can choose various IC devices that are reliable with low cost so that the fabrication on the package can be thus reduced. Once there is no limitation of choosing different IC devices, the package structure of the RSMMC can be varied in accordance with the needs of the market or the customers. Thus, its marketing competition can be increased.  
      The forgoing is considered illustrative of the principles of the invention. As variations and related embodiments may occur to those skilled in the art, it is to be appreciated the invention, and all suitable modifications and equivalents, are only to be limited by the scope of the claims following hereinafter.