Abstract:
A package method for a flash memory card and structure thereof is disclosed. A plurality of independent memory card module substrates are arranged on the substrate and those memory card module substrates are suspended and connecting with the substrate by a plurality of connecting bars. Chips are arranging on those memory card module substrates and the molding compound is utilizing to respectively cover chips, those memory card module substrates, wherein the molding compound is formed as a chamfered standard profile by performing a molding process with a upper molding substrate and a support substrate. Then punch, and grind the plurality of rugged bumps of those connecting bars to gain good cutting surface of the product and lower the cost.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    1. Field of the Invention 
         [0002]    The present invention generally relates to a semiconductor package technology, and more especially, relates to a package method for a flash memory card and the structure thereof. 
         [0003]    2. Description of the Prior Art 
         [0004]    Accordingly, the micro secure digital memory card (Micro SD card) is a light and handy, portable data storage device, it may use on different electronic apparatus, such as, personal computer, cell phone, digital camera . . . etc. As shown in  FIG. 1A  and  FIG. 1B , illustrating the front view and the back view of Micro SD card respectively. The shape of Micro SD card  100  is multilateral and has a salient shape and a re-entrant shape  102  on one side. The prior cutting process of Micro SD card is to cut and separate the plurality of Micro SD card assemblies to a plurality of unitary assemblies. 
         [0005]    Referring to  FIG. 2 , it is the front view diagram and illustrates the generally forming method of the unitary Micro SD card. To arrange the plurality of Micro SD card module substrates  120  on a substrate  110 , after placing chips (not shown) on the proper location, then utilize the molding component  130  to cover the whole surface of the substrate  110 , which includes the plurality of unitary Micro SD card module substrates  120 . Wait until the molding compound  130  harden, exploiting the water jet or the laser-cutting machine (not shown) to separate a plurality of Micro SD card assemblies to the plurality of unitary Micro SD card  100  accurately. However, the laser-cutting machine and the water jet machine are very expensive equipments, the water jet machine even needs extra abrasives to achieve cutting purpose. Besides, no matter using laser or water jet method to process cutting, it must spend more time to calibrating the machine precisely and the cutting process is so slow. The productivity is lower relatively. The cutting surface is rough, the size is difficult to control and it easily causes the problem as plugging in or out. 
         [0006]      FIG. 8A ,  FIG. 8B  and  FIG. 8C  are the side view and the upward view of Micro SD card according to the prior art after the cutting process. Such as shown in  FIG. 8A , the Micro SD card module substrates  120  is exposed at the lateral side of the Micro SD card  100 . Hence, metal wire  122  on the Micro SD card module substrate  120  is also exposed so as to easily cause the pollution of the metal dust and the poor-contacting problem. The general solution to overcome this problem is to open the window at the edge of the solder mask, then to etch back to remove the metal wire, and next to perform the prior package process. However, such as shown in  FIG. 8B  and  FIG. 8C , after chamfering the Micro SD card  100 , it cannot use the same solution to overcome the problem that the metal wire  122  on the Micro SD card module substrate  120  is exposed. 
         [0007]    In order to achieve the goal that Micro SD card has no rough surface after cutting, the expensive cutting equipment, the low productivity, and the exorbitant cost are the part portion of blemish in an otherwise perfect thing. Therefore, these are urgent issues that enterprises need to overcome currently. 
       SUMMARY OF THE INVENTION 
       [0008]    According to the issue mentioned previously, the present invention provides a package method for a flash memory card and the structure thereof. 
         [0009]    It is an object of the present invention to provide a package method for a flash memory card and the structure thereof, to arrange a plurality of memory card module substrates and a plurality of connecting bars on a substrate. When processing the molding steps, just needs injecting the molding compound into the memory card module substrate instead of injecting the molding compound into the whole substrate. As this result, the present invention avoids the waste of the molding compound and reduces the cost of the molding compound. 
         [0010]    Another object of the present invention is to provide a package method for a flash memory card and the structure thereof, to arrange a plurality of memory card module substrates and a plurality of connecting bars on a substrate. When processing the molding steps, just needs injecting the molding compound into the memory card module substrate instead of injecting the molding compound into the whole substrate, wherein the cover area of the molding component is larger than the area of the memory card module substrate so as the present invention can design the specific shape with accurately dimension and have a stable manufacturing process without cutting the large area. 
         [0011]    It is an object of the present invention to provide a package method for a flash memory card and the structure thereof, exploiting the punch method to separate the plurality of connecting bars arranged on the substrate. The punch method can separate the substrate and the memory card package directly, without using the expensive cutting equipment (such as laser cutting machine or water jet) to process the cutting. The present invention can reduce the cost of the production equipment and also raise the productivity. 
         [0012]    Another object of this invention is to provide a package method for a flash memory card and the structure thereof, exploiting the punch device to go though the package cutting process. Regarding the cutting speed of the punch device is faster than the traditional laser-cutting machine or water-jet machine. The present invention can raise the productivity due to the short cutting processing time. 
         [0013]    Another object of this invention is to provide a package method for a flash memory card and the structure thereof. A plurality of connecting bars are designed on the substrate to avoid the molding compound peeling or the package cracks due to the punch location excessively close to the package when punching. It can raise the production yield furthermore. 
         [0014]    Another object of the present invention is to provide a package method for a flash memory card and the structure thereof. Accurately polish the extra and unnecessary molding compound, which caused by the punch process, to achieve the goal that package has no rough surface after punching. 
         [0015]    One object of the present invention provides a package method for a flash memory card and the structure thereof, the molding component can directly mold as a chamfered standard shape to simplify the chamfering step. Wherein, the cover area of the molding component is larger than the area of the memory card module substrate, so as the metal wire on the memory card module substrate would not be exposed at the sidewall of the memory card module substrate to cause the contamination of the metal dust or the poor-connect. 
         [0016]    Accordingly, one embodiment of the present invention provides a package method for a flash memory card includes: providing a substrate with a plurality of memory card module substrates arranged thereon, wherein each of memory card module substrates is linking with the substrate with a plurality of connecting bars; utilizing a molding component to respectively cover the memory card module substrates and expose a portion of connecting bars; cutting the connecting bars to obtain a plurality of memory card packages; and smoothing the connecting bars protruding from each of memory card packages. 
         [0017]    Another embodiment of the present invention provides a package structure for a flash memory card includes: a substrate with a plurality of memory card module substrates arranged thereon, wherein each of memory card module substrates is linking with the substrate with a plurality of connecting bars; and a molding component to respectively cover the memory card module substrates to expose a portion of connecting bars. 
         [0018]    The other embodiment of the present invention provides a package structure for a flash memory card includes: a memory card module substrate having a plurality of connecting bars to link with a substrate; and a molding component to cover the memory card module substrate and the connecting bars. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0019]    The foregoing aspects and many of the accompanying advantages of this invention will become more readily appreciated as the same becomes better understood by reference to the following detailed description, when taken in conjunction with the accompanying drawings, wherein: 
           [0020]      FIG. 1A  and  FIG. 1B  illustrate the front view and the back view of Micro SD card respectively; 
           [0021]      FIG. 2  illustrates the generally forming method of the unitary Micro SD card; 
           [0022]      FIG. 3A ,  FIG. 3B  and  FIG. 3C  illustrate an embodiment of the present invention; 
           [0023]      FIG. 3D  illustrates the side view of AA′ cross-section line of  FIG. 3C ; 
           [0024]      FIG. 4A ,  FIG. 4B ,  FIG. 4C  and  FIG. 4D  illustrate the slightly modification smoothing steps in accordance with an embodiment of the present invention; 
           [0025]      FIG. 5  is a flow chart illustrating an embodiment of the present invention; 
           [0026]      FIG. 6  illustrates the shape of the connecting bars, the distribution of the connecting bars, and the mount of the connecting bars in accordance with different embodiments of the present invention; 
           [0027]      FIG. 7  illustrates an embodiment of the present invention; 
           [0028]      FIG. 8A ,  FIG. 8B  and  FIG. 8C  are the side view and the upward view of Micro SD card according to the prior art; 
           [0029]      FIG. 9  is a flow chart illustrating an embodiment of the present invention; and 
           [0030]      FIG. 10A ,  FIG. 10B  and  FIG. 10C  illustrate an embodiment of the present invention. 
       
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
       [0031]    To explain a package method for a flash memory card and the structure thereof with preferred embodiments of the present invention; 
         [0032]    First, referring to  FIG. 3A , illustrating the substrate design in accordance with an embodiment of the present invention. In the present embodiment, there are a plurality of flash memory card module substrates  20  arranged on a substrate  10 . Each of those flash memory card module substrates  20  is independently linking with the substrate  10  with connecting bars  22 . Among those connecting bars  22  is the hollow portion of the substrate  10 . Referring to  FIG. 3B , after placing the chip (not shown) on the proper location of the flash memory card module substrate  20 , a molding compound  30 , which made of epoxy, is covering each flash memory card module substrate  20  to expose a portion of connecting bars  22 . Wherein the geometric figure formed by the molding compound  30  is similar to the flash memory card module substrate  20  but the cover area is a little bit larger than the size of the flash memory card module substrate  20 . Besides, in order to avoid the molding compound squeeze out while molding, it may paste tapes on the surface of the cavity (not shown) and let the substrate  10 , the flash memory card module substrate  20  and the cavity (not shown) close together and the molding compound  30  will not squeeze out. Then, a punch device is utilized to perform the singulation step; those connecting bars  22  are dismembered to form a plurality of memory card packages. 
         [0033]    Please refer to  FIG. 3C , in order to avoid the molding compound  30  peeling or the memory card package cracks due to the punch location excessively close to the memory card package while punching, there is a little interval between the punch location and the memory card package. Therefore, the memory card package after punching has a plurality of bumps, the side view of AA′ cross-section line is shown in  FIG. 3D . These bumps are the part portion of the original connecting bars  22  of the substrate  10 . Referring to  FIG. 3C , in one embodiment, the package structure for a flash memory card of the present includes a memory card module substrate  20  having a plurality of connecting bars  22  to link with a substrate (not shown in Figure); and a molding component  30  to cover the memory card module substrate  20  and those connecting bars  22 . Wherein, a portion of connecting bars  22  is exposed to the molding component  30 . 
         [0034]    Next,  FIG. 4A ,  FIG. 4B ,  FIG. 4C  and  FIG. 4D  illustrating the slightly modification smoothing steps in accordance with an embodiment of the present invention, it can use the saw-tooth tool  40  to polish the extra, unnecessary molding compound. In one embodiment, it may use several steps to grind the detail portion by different polish tools. For example, in the beginning of the slightly modification smoothing steps, it may choose rough pellet or surface tools to grind, polish those bumps of connecting bars  22  promptly. Please refer to  FIG. 4B , until those bumps almost disappear, now may choose smoother pellet or surface tools to slightly modify smoothing the whole edge of the memory card package. Referring to  FIG. 4C , start the chamfer steps to form the memory card package with the international standard size and shape, after the whole edge of the memory card package become smoothly. It is to be understood, the chamfer step can also separate to several steps to process. After punching, the size of the memory card package will become international standard size by using the slightly modification smoothing steps. By the way, the slightly modification smoothing tool not limited on the saw-tooth tool  40 , it may be suitable for using the dice (which made of diamond and used to dicing the wafer) to dice the tiny bump and the bump which very close to the memory card package. Or it may choose the high rotating speed router (which used to route and to form the print circuit board) to remove those bumps to smooth surface. 
         [0035]      FIG. 5 . is a flow chart illustrating an embodiment of the present invention. Simultaneously referring to  FIG. 3B  and  FIG. 5 , providing a substrate  10  having a plurality of memory card module substrates  20 , wherein those memory card module substrates  20  are linking with the substrate  10  with a plurality of connecting bars  22  and placing the chip on the proper location of each of those memory card module substrates  20  (step  10 ). And then utilize the molding compound  30  to cover the memory card module substrates  20  (step  20 ) to expose a portion of connecting bars  22 . While the package process completed and the molding component  30  harden, start punch and separate those memory card packages (step  30 ) and then slightly modify smoothing the bump at the edge of the memory card package step by step (step  40 ), wherein the slightly modification smoothing step includes grind, polish and chamfer. 
         [0036]      FIG. 6  is illustrating the shape of the connecting bars  22 ′, the distribution of the connecting bars  22 ′, and the mount of the connecting bars  22  in accordance with different embodiments of the present invention. Those connecting bars  22 ′ are used to connect those memory card module substrates  20  and not limited as shown in this embodiment of the present invention. The location, the shape, and the size of the connecting bars  22 ′ may be variable, just depend on the different arrangements of memory card module substrates  20  on the substrate  10 . The shape of those connecting bars is in polygon, bar, round shape, or multi-radian shape. 
         [0037]    Referring to  FIG. 7 , in the present embodiment, the cover area of the molding component  30  of the flash memory SIM card is larger than the memory card module substrate  20 , wherein there are golden fingers  24  arranged on the memory card module substrate  20  at the back side of the flash memory SIM card. However, the present invention can apply to the micro SD memory card or the package method of the micro SD memory card, but not limited herein. The present invention can apply to kinds of the package of the flash memory card. 
         [0038]    Besides, referring to  FIG. 9  and  FIG. 3B , first providing a substrate  10  having a plurality of memory card module substrates  20 , wherein those memory card module substrates  20  are linking with the substrate  10  with a plurality of connecting bars  22  and placing the chip (not shown in the figure) on the proper location of each of those memory card module substrates  20  (step  10 ). Next, electrically connect the chip and memory card module substrate  20  (step  12 ), and then utilize the molding compound  30  to respectively cover the chip and the upper surface of the memory card module substrates  20  to expose the lower surface of the memory card module substrate  20  and a portion of connecting bars  22  by using a upper-mold substrate and a supporting substrate to perform a molding process to form the molding component (step  22 ). Wherein the molding component is directly mold as a chamfered standard profile. While the package process completed and the molding component  30  harden, start punch and separate those memory card packages (step  30 ) and then slightly modify smoothing the bump at the edge of the memory card package step by step (step  40 ), wherein the slightly modification smoothing step includes grind and polish. Owing to the molding component is directly mold as a chamfered standard profile, in the present invention; it is not necessary to perform the chamfer step to each memory card package. 
         [0039]    Following the forgoing description, referring to  FIG. 10A ,  FIG. 10B  and  FIG. 10C , in the present embodiment, a upper-substrate  60  and a supporting substrate  62  are utilized to perform the molding process to form the molding component  30 . The upper-mold substrate  60  has a through hole  64  thereon for injecting the molding material. The supporting substrate  62  provides the supporting effect and can be replaced with a bearing plate or other base substrate. The molding component  30  is respectively cover the chip  50  and the upper surface of the memory card module substrate  20  and to expose the lower surface of the memory card module substrate  20  and a portion of connecting bars (not shown in the figure). In the present invention, the chamfered standard profile of the molding component  30  is modeled the profile by the upper-mold substrate  60 , such as shown in  FIG. 10B . However, the present invention is not limited herein, the chamfered standard profile of the molding component  30  can be also modeled the profile by the supporting substrate  62 , such as shown in  FIG. 10A . 
         [0040]    Please referring to  FIG. 10C , in the package structure of the present embodiment, at least a chip  50  is arranged on the memory card module substrate  20 , the chip  50  is electrically connecting with the memory card module substrate  20  by wire-bonding or other ways. A molding component  30  is cover the chip  50  and the upper surface of the memory card module substrate  20  to expose the lower surface of the memory card module substrate  20 . The molding component  30  is directly mold as a chamfered standard profile. Besides, not shown in the figure, whether the molding component  30  covers or not covers connecting bars depending on the process requirement. There is a golden finger (not shown in the figure) arranged on the upper surface of the memory card module substrate  20 . 
         [0041]    Accordingly, one of features of the present invention is to arrange a plurality of memory card module substrate linking with the substrate with a plurality of connecting bars. It utilizes the punch method to separate connecting bars to form a plurality of memory card packages. Due to the buffer space between the connecting bars and the memory card package, it can avoid the molding compound peeling or the package cracks due to the punch location excessively close to the package when punching so as to raise the production yield. In the molding step, the molding component would not completely cover the whole substrate but only perform the molding step on the memory card module substrate so as can reduce the cost of the molding material. Furthermore, the punch device is cheaper and faster than the traditional laser-cutting machine or water-jet machine so as to reduce the cost and to raises the productivity. 
         [0042]    To sum up the forgoing, the present invention utilizes the arrangement of a plurality of memory card module substrates and a plurality of connecting bars on a substrate. When processing the molding steps, just needs injecting the molding compound into the memory card module substrate instead of injecting the molding compound into the whole substrate. As this result, the present invention avoids the waste of the molding compound and reduces the cost of the molding compound. Wherein, the cover area of the molding component is larger than the area of the memory card module substrate so as the present invention can design the specific shape with accurately dimension and have a stable manufacturing process without cutting the large area. The present invention utilizes the punch method to separate the plurality of connecting bars arranged on the substrate. The punch method can separate the substrate and the memory card package directly, without using the expensive cutting equipment (such as laser cutting machine or water jet) to process the cutting. The present invention can reduce the cost of the production equipment and also raises the productivity. Hence, the present invention utilizes the punch device to go though the package cutting process. Regarding the cutting speed of the punch device is faster than the traditional laser-cutting machine or water-jet machine. The present invention can raise the productivity due to the short cutting processing time. A plurality of connecting bars are designed on the substrate to avoid the molding compound peeling or the package cracks due to the punch location excessively close to the package when punching. It can raise the production yield furthermore. Accurately polish the extra and unnecessary molding compound, which caused by the punch process, to achieve the goal that package has no rough surface after punching. In the present invention, the molding component can directly mold as a chamfered standard shape to simplify the chamfering step. Wherein, the cover area of the molding component is larger than the area of the memory card module substrate, so as the metal wire on the memory card module substrate would not be exposed at the sidewall of the memory card module substrate to cause the contamination of the metal dust or the poor-connect. 
         [0043]    While the present invention is susceptible to various modifications and alternative forms, a specific example thereof has been shown in the drawings and is herein described in detail. It should be understood, however, that the invention is not to be limited to the particular form disclosed, but to the contrary, the invention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the appended claims.