Abstract:
A method of manufacturing electronic module is provided. The method can perform selective partial molding by forming the tapes in a predetermined area on the circuit substrate, setting electronic components out the predetermined area on the circuit substrate, forming the molding member encapsulating the whole circuit substrate and removing the tapes along of the molding member thereon. Following, forming an EMI shielding layer on the molding member and setting optoelectronics in the predetermined area on the circuit substrate could protect the electronic components from electromagnetic disturbance and avoid the optoelectronics being encapsulated.

Description:
CROSS REFERENCE TO RELATED APPLICATION 
       [0001]    This application is a continuation-in-part of U.S. application Ser. No. 13/955,149 filed on Jul. 31, 2013 and entitled “METHOD OF MANUFACTURING ELECTRONIC PACKAGE MODULE”, now in condition for allowance. 
     
    
     BACKGROUND 
       [0002]    1. Field of the Invention 
         [0003]    The instant disclosure relates to an electronic module and method of making the same; in particular, to an electronic module having selective molding and method making the same. 
         [0004]    2. Description of Related Art 
         [0005]    Conventional electronic module includes a plurality of electronic components disposed on a circuit board. In addition, the electronic component modules may include molding material to encapsulate the electronic components for protection. 
         [0006]    However, some electronic components like connectors or optoelectronics are not suitable for encapsulation, for example, the CMOS image sensor (CIS), charge-coupled device (CCD), and light emitting diode (LED). In order to protect some electronic components and remain the function of other components that are not suitable for encapsulation, a “partial molding” is then developed. 
         [0007]    Conventional “partial molding” is achieved by mold chase, and the molding material is added to form the molding member. However, because of fluid adhesion, the molding material tends to form air bubbles or void at the mold cavity or the gap between the components and the circuit board. The air bubbles or the voids with moisture and in the following heating process they may cause “popcorn” issue which leads to low yield rate. Furthermore, after molding is completed by the mold chase, the mold chase has to be removed. For removing the mold chase, a draft angle has to be preserved when designing the mold chase. Typically, the acute angle between the mold and the circuit board is approximately 70 degree which reduces the overall usage of the printed circuit board. Moreover, whenever there is a different configuration, such as irregular shape of the molding, the mold chase has to be redesigned. Therefore, the cost is increased and the design consideration of mold chase becomes more complicated. 
       BRIEF SUMMARY OF THE INVENTION 
       [0008]    The instant disclosure provides an electronic module and method of making the same for selective molding electronic components. 
         [0009]    According to one embodiment of the instant disclosure, the method includes: providing a circuit substrate. The circuit substrate includes a first surface, at least one first ground pad and a first predetermined area disposed on the first surface. Then, a first tape is formed onto the first predetermined area. Next, at least one electronic component is disposed outside the first predetermined area. After then, a first molding member is formed. The first molding member covers the first tape and the electronic components. Subsequently, the first molding member and the first tape above the first predetermined area are removed. 
         [0010]    In the step of forming the tape on the predetermined area, a tape is attached on the entire circuit substrate. Then, laser is used to trench the tape above the ground pad. Subsequently, the tape outside the first predetermined area is removed, such that in the predetermined area, the tape remains. 
         [0011]    In the step of removing the molding member, laser may be used to trench the molding member above the ground pad that surrounds the predetermined area. 
         [0012]    In the step of removing the molding member, laser may be used to trim the molding member above the predetermined area. 
         [0013]    In the step of removing the tape above the predetermined area, heating may be used to facilitate the process. 
         [0014]    The tape may be UV tape. In the step of removing the tape above the predetermined area, UV light may be used to shine on the tape and removed thereby. 
         [0015]    The method of manufacturing the electronic module may further includes disposing the optoelectronic, connector or the like that are not suitable to be encapsulated on the predetermined area. According to an embodiment, after the removal of the tape, a mask layer is formed within the predetermined area and not covers the ground pad, and further formed the EMI shielding layer entirely and electrically connected to the ground pad. Then the mask layer is removed, and the optoelectronic is disposed on the predetermined area. After laser trenches the molding member above the ground pad, the entire area is formed with EMI shielding layer. The EMI shielding layer and the ground pad are electrically connected, and the tape in the predetermined area is then removed. The optoelectronic is subsequently disposed on the predetermined area. 
         [0016]    The circuit substrate may further include side ground pads, and the EMI shielding layer and the side ground pad are electrically connected. 
         [0017]    The electronic module of the instant disclosure may further include a circuit substrate, electronic components, molding members, an EMI shielding layer, optoelectronics and side ground pads. The circuit substrate includes a surface, ground pad and a predetermined area. The predetermined area and the ground pad are disposed on the surface. The electronic components are disposed on the surface outside the predetermined area. The molding member encapsulates the electronic components and each side of the molding member and the surface form an angle between 85 and 90 degrees. The EMI shielding layer covers the molding member, and it is electronically connected to the ground pad. The optoelectronics are disposed on the surface of the predetermined area. The side ground pad is disposed on a side of the circuit substrate, and the EMI shielding layer is electrically connected to the side ground pad. 
         [0018]    By the abovementioned arrangement, the method of manufacturing electronic module can undergo selective molding without complex molds or procedure. The area that requires molding are formed with molding member and metal coating, such that electromagnetic interference (EMI) is avoided, and the optoelectronics are less likely to be affected by the molding members. 
         [0019]    In order to further understand the instant disclosure, the following embodiments are provided along with illustrations to facilitate the appreciation of the instant disclosure; however, the appended drawings are merely provided for reference and illustration, without any intention to be used for limiting the scope of the instant disclosure. 
     
    
     
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS 
         [0020]      FIGS. 1A-1E  are schematic views showing the steps of manufacturing electronic module in accordance with an embodiment of the instant disclosure; 
           [0021]      FIG. 2  is a top view of an electronic module with an irregular area formed by a method of manufacturing electronic module in accordance with an embodiment of the instant disclosure. 
           [0022]      FIGS. 3A-3E  are cross-sectional views of the steps of forming electronic module with optoelectronics in an predetermined area in accordance with an embodiment of the instant disclosure; 
           [0023]      FIGS. 4A-4D  are cross-sectional views of the steps of forming electronic module with optoelectronics in an predetermined area in accordance with another embodiment of the instant disclosure; 
           [0024]      FIG. 5  is a cross-sectional view of an electronic module including side ground pads in accordance with an embodiment of the instant disclosure; and 
           [0025]      FIGS. 6A-6I  are cross-sectional views showing a method for manufacturing electronic module implementing on a two-sided molding in accordance with an embodiment of the instant disclosure. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0026]    The aforementioned illustrations and following detailed descriptions are exemplary for the purpose of further explaining the scope of the instant disclosure. Other objectives and advantages related to the instant disclosure will be illustrated in the subsequent descriptions and appended drawings. 
         [0027]    Please refer to  FIGS. 1A-1E .  FIGS. 1A ,  1 C and  1 E are cross-sectional view of a method of manufacturing electronic module in accordance with an embodiment.  FIGS. 1B and 1D  are top view of the method of manufacturing electronic module of the embodiment. 
         [0028]    In this embodiment, please refer to  FIGS. 1A and 1B . The method of manufacturing electronic module of the instant disclosure includes, firstly, preparing a circuit substrate  11 . The circuit substrate  11  has a surface  12 , a predetermined area  101  on the surface  12  and ground pad  111 . The position of the ground pad  111  can be used to define the predetermined area and the non-predetermined area. In the present embodiment, the ground pad  111  surrounds the predetermined area, and in another embodiment, the width of the ground pad  111  is 200 μm, but the instant disclosure is not limited thereto. The position, shape and dimension of the ground pad  111  are subject to change for different requirement. 
         [0029]    Firstly of all, in order to form tape within the predetermined area, a suitable sized tape can be attached to the predetermined area  101 . Alternatively, a large piece of tape can be attached to the entire circuit substrate  11 , and laser is used to trench the tape to the peripheral region of the predetermined area, and then the partial tape outside the predetermined area  101  is removed, such that tape  13  is only present within the predetermined area  101 . 
         [0030]    The electronic component  21  is disposed on the surface  12  outside the predetermined area  101 . It can be disposed by surface mount technology (SMT), and the electronic component  21  may be other elements other than optoelectronic, such as all kinds of active, passive components and the instant disclosure is not limited thereto. The optoelectronic in this specification refers to any components that are not suitable to be encapsulated by molding member, for example, CMOS image sensor, CCD, light emitting diode, connector, insertion hole, receptacle or the like. In addition, components that are suitable to be encapsulated are referred to as electronic components. 
         [0031]    Please refer to  FIG. 2 .  FIG. 2  is a top view of an electronic module with an irregular area formed by a method of manufacturing electronic module in accordance with an embodiment of the instant disclosure. The predetermined area  102  in  FIG. 2  is irregular. The predetermined area is not limited by number, area size or shape. The predetermined area is used for locating optoelectronics, connector or the like that are not suitable to be encapsulated by the molding member  15  in the following process. The following implementation is adaptable to the predetermined areas  101  and  102 . 
         [0032]    After the abovementioned step shown in  FIGS. 1A and 1B , such as the step of forming tape within the predetermined area and the step of disposing at least one electronic component  21 , the molding member  15  is formed on the entire circuit substrate  11 . The molding member  15  covers the tape  13  along with the circuit substrate  11  and the electronic components  21  outside the predetermined area  101  and ground pad  111 . The formation of the molding member  15  is achieved by transfer molding or injection molding. The coverage of the tape  13  may overlap the ground pad  111  or immediately adjacent to the ground pad  111  without overlapping, and the instant disclosure is not limited thereto. 
         [0033]    Please refer to  FIGS. 1C and 1D . After the formation of molding member  15 , laser is used to trench around the peripheral region of the predetermined area  101 . In other words, a trench is cut along the ground  111 . In an embodiment, the width of the trench is approximately 100 μm. The ground pad  111  is a metal layer, and the main material of the molding member  15  may include resin. Because of the different laser absorption level between the ground pad  111  and molding member  15 , the ground pad  111  may act as a stop for laser cutting. However, the instant disclosure is not limited to this approach, and any means that cuts the molding member  15  alone and leaves the circuit substrate  11  is acceptable. For example, contour cutting may also be used to trench the molding member  15 . It should be noted that in the instant disclosure, laser cutting is used, and the molding member does not need to reserve for a draft angle (e,g, approximately 20 degree). Therefore, after trenching, the side wall of the molding member  15  and the surface  12  form an angle a ranging between 85 and 90 degree. Compared to the conventional electronic module, the angle a is closer to 90 degree. 
         [0034]    If the tape is a thin film, for example, thickness ranging between 20 and 50 micrometer (μm), when the tape  13  is removed, the molding member  15  remains on the circuit substrate  11  outside the predetermined area. The tape  13  may be heat tape or UV tape. If the tape is a heat tape, it can be removed by heating. In an embodiment, it is heated to 175° C., and the tape is removed by any pickup device. If the tape is a UV tape, the tape can be removed by shining UV light, and the instant disclosure is not limited to these two types of tapes. 
         [0035]    In another embodiment of the instant disclosure, the tape is a thick film, for example, thickness being 0.2 mm. After laser trenches the molding member  15  on the predetermined area, laser is used to trim the molding member  15  on the predetermined area (i.e., the molding member  15  above the tape  13 ). In other words, after the molding member  15  on the predetermined area  101  is removed, the tape  13  is then removed, such that only the molding member  15  remains on the circuit substrate  11  outside the predetermined area  101 . 
         [0036]    In another embodiment of the instant disclosure, the molding member  15  outside the predetermined area  101  covers with the EMI shielding layer  19  and is electrically connected to the ground pad  111 , and the optoelectronic  22  is disposed on the predetermined area  101 . 
         [0037]    Please refer to  FIGS. 3A to 3E  showing the processes and corresponding cross-sectional views of forming electronic module with the optoelectronic  22  within the predetermined area  101 . In the instant embodiment, after the tape  13  is removed (as shown in  FIG. 3A ), a mask layer  18  is disposed on the surface  12  within the predetermined area  101  and does not cover the ground (as shown in  FIG. 3B ). The material of the mask layer  18  is not limited as long as it can be easily removed. Subsequently, an entire EMI shielding layer  19  is formed (as shown in  FIG. 3C ). The EMI shielding layer  19  may be formed by spray coating, electroless plating or sputtering, and the instant disclosure is not limited thereto as long as the EMI shielding layer  19  and the ground pad  111  keep electrical connection. In this regard, once the mask layer  18  is removed, the EMI shielding layer  19  covers the molding member  15  outside the predetermined area  101  and is electrically connected to ground pad  111  (as shown in  FIG. 3D ), such that EMI shielding function can be offered to the electronic component  21 . Then, the optoelectronic  22  is disposed within the predetermined area  101  (as shown in  FIG. 3E ), the optoelectronic  22  may be disposed by surface mount technology (SMT), and the instant disclosure is not limited thereto. Accordingly, the optoelectronic  22  is not encapsulated by the molding member, and the optoelectronic  22  is free from electromagnetic interference (EMI). 
         [0038]    In another embodiment of the instant disclosure, please refer to  FIGS. 4A to 4D .  FIGS. 4A to 4D  show the processes and corresponding cross-sectional views of forming electronic module with optoelectronic  22  within the predetermined area  101 . In the instant embodiment, after laser trenches the molding member  15  surrounding the predetermined area  101  (as shown in  FIG. 4A ), the entire EMI shielding layer  19  is formed (as shown in  FIG. 4B ). The formation of the EMI shielding layer  19  is identical as previously mentioned. The EMI shielding layer  19  should be electrically connected to the ground pad  111 . Next, the tape  13  is removed, and the molding member  15  outside the predetermined area  101  is covered with the EMI shielding layer  19  and is electrically connected to the ground pad  111  (as shown in  FIG. 4C ), such that EMI shielding function can be provided. Then, the optoelectronic  22  is disposed within the predetermined area  101  (as shown in  FIG. 4D ). In practical, in the situations such as the distance between each molding member  15  or the height of the molding member  15  will be result in electrical disconnection of EMI shielding layer  19  and ground pad  111 , the embodiment as shown in  FIGS. 3A to 3E  could be used to in place of directly forms the EMI shielding layer  19  as shown in  FIGS. 4A to 4B . 
         [0039]    In addition, for increasing the effectiveness of the protection against electromagnetic interference, the electronic module may further include at least one side ground pad  112  disposed on a side of the circuit substrate  11  and electrically connected to EMI shielding layer  19  as shown in  FIG. 5 . 
         [0040]    The instant disclosure also provides a method of manufacturing double-sided electronic module by using the aforementioned process. Most of the process detail can be referred back to the previous embodiments. Please refer to  FIGS. 6A to 6I . In  FIG. 6A , the electronic component  41  is disposed on a first surface of the circuit substrate  31  outside the predetermined area. The tape  33  is attached within the predetermined area. The ground pad  311  surrounds the predetermined area, and the side ground pad  312  is disposed around the side of the substrate  31 . If the height of electronic component  41  is relatively shorter, the tape  33  attached to the first surface can be a thicker tape, and its thickness may be slightly higher than the electronic component  41 . 
         [0041]    Subsequently, the first surface of the circuit substrate  31  is formed with the molding member  35 . Because the tape  33  is thicker, the height of the molding member  35  is approximately the same as the tape  33 , such that the molding member  35  can completely encapsulate the electronic component  41 , as shown in  FIG. 6B . In addition, because the height of the molding member  35  is the same as the tape  33 , in the following formation of the EMI shielding layer  39 , the tape does not need to be removed and sputtering can be performed straight afterwards. 
         [0042]    Then, the molding member  35  formed on the first surface of the circuit substrate  31  is trenched, as shown in  FIG. 6C . For the convenience of the following formation of the EMI shielding layer  39 , the trench is wider for easier coating. 
         [0043]    After that, the trenched molding member  35  on the first surface of the circuit substrate  31  undergoes coating and is covered with a layer of ink  37 , as shown in  FIG. 6D . The ink  37  serves to prevent any contamination from dust or foreign particles occurring to where it covers. The ink  37  can be washed off by chemical solvent, and the particles thereon can be rinsed off at the same time. The layer underneath the ink layer is therefore clean. 
         [0044]    Please refer to  FIG. 6E . The circuit substrate  31  is turned over to the other side, and starts to mold the second surface of the circuit substrate  31 . The second surface is opposite to the first surface. The tape  53  is attached to the predetermined area on the second surface. In the embodiment, the predetermined area on the second surface surrounds the non-predetermined area. However, the shape of the predetermined area is not limited to the present disclosure. The ground pad  511  can be disposed around the non-predetermined area to act as a stop for laser cutting, in other words, the ground pad  511  is located between the predetermined area and the non-predetermined area. In this embodiment, the height of electronic component  61  disposed outside the predetermined area of the second surface relatively higher than that of electronic component  41  on the first surface, so that a thinner tape  53  could be used at the second surface for attaching on predetermined area. It should be noted that in the instant embodiment, two sides of the circuit substrate  31  (i.e. the first and second surface) are used to describe a preferable implementation, and the instant disclosure is not limited thereto. The height of the electronic components and the position of the predetermined area are not dependent to each other. The combination of the height of the electronic component and the thickness of the tape is decided in relation to a more convenient process, and it may be subject to change. 
         [0045]    After the electronic component  61  is disposed on the second surface outside the predetermined area (i.e. the non-predetermined area), the molding member  55  can be formed as shown in  FIG. 6F . Subsequently, the tape  53  and the molding member  55  are removed, and the ink  57  is formed on the predetermined above the second surface, as shown in  FIG. 6G . 
         [0046]    Furthermore, the entire circuit substrate can undergo the processing of EMI shielding layer  59  and then be cut into form individual modules. Alternatively, the entire circuit substrate can undergo cutting to form individual modules first and then processing the EMI shielding layer  59 , such that the exterior of each individual module is formed with the EMI shielding layer  59 , as shown in  FIG. 6H . 
         [0047]    Following that, the ink  37 ,  57  are washed off, and the tape  33  is removed. The resulting circuit substrate  31  has selective molding at two sides and each side has complete EMI shielding layer  39 ,  59  respectively. Finally, the optoelectronic  62  is disposed on the predetermined area and the electronic module is complete, as shown in  FIG. 6I . 
         [0048]    It should be noted that the two-sided molding does not intend to limit the instant disclosure. If the predetermined areas of the two sides are both at the central region, a complete electromagnetic mask layer can be shared between the two sides. That is to say, the ink  37  and the EMI shielding layer  59  can be omitted. More specifically, the substrate undergoes the process up to the step as shown in  FIG. 6C , and the EMI shielding layer  39  is formed to cover the entire substrate to simplify the process. 
         [0049]    The descriptions illustrated supra set forth simply the preferred embodiments of the instant disclosure; however, the characteristics of the instant disclosure are by no means restricted thereto. All changes, alternations, or modifications conveniently considered by those skilled in the art are deemed to be encompassed within the scope of the instant disclosure delineated by the following claims.