Abstract:
A package structure is provided, including an electronic element with a low frequency, a shielding member connected to the electrosnic element, and an encapsulant covering the electronic element and the shielding member, such that the electronic element is shielded from erroneous signals.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    1. Field of the Invention 
         [0002]    The present invention relates to package structures, and, more particularly, to a package structure having an electromagnetic shielding function. 
         [0003]    2. Description of Related Art 
         [0004]    With the rapid growth in electronic industry, there is an increasing need in developing electronic products with multi-functionality and high performance. As wireless technology has been widely applied in all types of electronic products which are capable of transmitting or receiving wireless signals, the electronic products are configured with a shielding function in order to prevent electromagnetic interference (EMI). 
         [0005]    Electronic products up to date have been developed towards miniaturization and high operational speed. In particular, these electronic products have been widely incorporated into communication products, such as cell phones, laptops, etc. These types of electronic products require the use of radio frequency chip of high frequency. These radio frequency chips may be disposed in an integrated circuit, a digital signal processor, (DSP) or a base band chip, which are likely to be interfered with respect to each other, and, as a result, require electromagnetic shielding. 
         [0006]    As shown in  FIG. 1 , an conventional radio frequency module  1  comprises a carrier  10 , a plurality of electronic components  11  electrically connected to the carrier  10 , an encapsulant  13  made by epoxy resin and encapsulating the electronic components  11 , and a metal thin film  12  formed and covering the encapsulant  13 . With the metal thin film  12 , the electronic components  11  of the radio frequency module  1  is protected from the interference of EMI. 
         [0007]    However, in the radio frequency module  1  the metal thin film  12  is formed on an external side of the encapsulant  13 . In other words, the encapsulant  13  is formed between the metal thin film  12  and the interference source (i.e., electronic component  11 ). When the electronic component  11  is a radio frequency chip, the metal thin film  12  covers top and side surfaces of the encapsulant  13 , resulting in a poor shielding effect, causing erroneous signals of the electronic component  11  of low frequency. 
         [0008]    Accordingly, there is an urgent need to solve the above-mentioned drawbacks of the prior art. 
       SUMMARY OF THE INVENTION 
       [0009]    In view of the above-mentioned drawbacks of the prior art, the present invention discloses a package structure, comprising: at least one electronic component with a low frequency; at least one shielding member coupled onto the at least one electronic component; and an encapsulant encapsulating the electronic component and the shielding member. 
         [0010]    In an embodiment, the electronic component is a package substrate, an active component, a passive component or a conductive circuit. 
         [0011]    In an embodiment, the low frequency refers to a frequency lower than or equal to 3 MHz. 
         [0012]    In an embodiment, the electronic component is a low frequency electronic component. 
         [0013]    In an embodiment, the shielding member is coupled onto at least one of the electronic components via a bonding layer, and the bonding layer is formed between the shielding member and the electronic component. 
         [0014]    In an embodiment, the shielding member is made of a soft ferrite material. 
         [0015]    In an embodiment, the heat resistance temperature of the shielding member is 300□. 
         [0016]    In an embodiment, another electronic component is disposed on the shielding member. 
         [0017]    In an embodiment, the width of the shielding member is less than, greater than or equal to the width of the electronic component. 
         [0018]    In an embodiment, the shielding member completely or partially covers the electronic components. 
         [0019]    In an embodiment, a portion of the shielding member is exposed from the encapsulant. 
         [0020]    In an embodiment, the encapsulant is not formed between the shielding member and the electronic components 
         [0021]    In an embodiment, the package structure further comprises a carrier that carries the electronic components and is electrically connected with the electronic components. 
         [0022]    Accordingly, in the package structure according to the present invention, the direct coupling of the shielding member to the low frequency electronic components, in replacement of the disposing of the shielding member on the external side of the encapsulant according to the prior art, can prevent the low frequency electronic component from generating erroneous signals. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0023]      FIG. 1  is a cross-sectional view showing a conventional radio frequency module; 
           [0024]      FIG. 2  is a cross-sectional view showing a package structure in accordance with a first embodiment of the present invention; wherein FIGS.  2 ′ and  2 ″ are other embodiments of  FIG. 2 ; 
           [0025]      FIGS. 3A-3E  are cross-sectional views showing package structures in accordance with different types of a second embodiment of the present invention; 
           [0026]      FIG. 4  is a cross-sectional view of a package structure in accordance with a third embodiment of the present invention; 
           [0027]      FIG. 5  is a cross-sectional view of a package structure in accordance with a fourth embodiment of the present invention; 
           [0028]      FIG. 6  is a cross-sectional view of a package structure in accordance with a fifth embodiment of the present invention; 
           [0029]    FIGS.  7  and  7 ′ are cross-sectional views of a package structure in accordance with a sixth embodiment of the present invention; and 
           [0030]      FIG. 8  is a cross-sectional view of a package structure in accordance with an seventh embodiment of the present invention. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0031]    The present invention is described in the following with specific embodiments, so that one skilled in the pertinent art can easily understand other advantages and effects of the present invention from the disclosure of the present invention. 
         [0032]    It should be noted that all the drawings are not intended to limit the present invention. Various modification and variations can be made without departing from the spirit of the present invention. Further, terms, such as “on”, “second”, “first”, and etc., are merely for illustrative purpose and should not be construed to limit the scope of the present invention. 
         [0033]      FIG. 2  is a cross-sectional view showing a package structure  2  in accordance with a first embodiment of the present invention. In an embodiment, the package structure  2  is a radio frequency module of a system in package (SiP). 
         [0034]    The package structure  2  comprises an electronic component  21 , a shielding member  22  coupled onto the electronic component  21 , and an encapsulant  23  encapsulating the electronic component  21  and the shielding member  22 . 
         [0035]    The electronic component  21  can be an active component, or a passive component, such as a capacitor or an inductor. In an embodiment, the electronic component  21  is a low frequency active component. 
         [0036]    The shielding member  22  has first and second surfaces  22   a  and  22   b . The first surface  22   a  of the shielding member  22  is coupled to an upper surface  21   a  of the electronic component  21  via a bonding layer  220  such as an adhesive, and the bonding layer  220  is formed between the first surface  22   a  of the shielding member  22  and the electronic component  21 . In an embodiment, the shielding member  22  is made of a soft ferrite material, and the heat resistance temperature of the shielding member can reach to 300□. 
         [0037]    The encapsulant  23  is not formed between the first surface  22   a  of the shielding member  22  and the electronic component  21 . 
         [0038]    In an embodiment, the package structure  2  further comprises a carrier  20  carrying the electronic component  21 , and the lower surface  21   b  of the electronic component  21  is coupled to the carrier  20 . 
         [0039]    In an embodiment, the carrier  20  is a circuit board or a ceramic board. A wiring layer (not shown) is formed on a surface of the carrier  20  and is electrically connected with the electronic component  21 . In an embodiment, the electronic component  21  is electrically connected to the wiring layer via a plurality of bonding wires  210 . 
         [0040]    In an embodiment, the carrier  20  has an inner wiring layer (not shown), and is externally connected to another electronic device  9  (such as a printed circuit board) via conductive elements  200  such as solder balls. 
         [0041]    The carrier  20  may be in a variety of types, and is not limited by what is shown in the drawings. 
         [0042]      FIGS. 3A-3E  are cross-sectional views showing the package structures  3   a ,  3   b ,  3   c ,  3   d  and  3   e  in accordance with a second embodiment of the present invention. The second embodiment differs from the first embodiment in the various types of the shielding members  32   a ,  32   b ,  32   c ,  32   d  and  32   e.    
         [0043]    As shown in  FIGS. 3A and 3E , the width  4  of the shielding members  32   a  and  32   e  is equal to the width t of the electronic component  21 . 
         [0044]    As shown in  FIGS. 3B and 3D , the width r′ of the shielding members  32   b  and  32   d  is greater than the width t of the electronic component  21 . 
         [0045]    As shown in  FIG. 3C , the width  4 ′ of the shielding member  32   b  is lesser than the width t of the electronic component  21 . 
         [0046]    In an embodiment, the electronic component  21  is electrically connected to the wiring layer (not shown) of the carrier  20  via a plurality of solder balls  210 ′ in a flip-chip manner. 
         [0047]    In an embodiment, the shielding members  32   a  and  32   b ,  32   d  completely cover the upper surface  21   a  of the electronic component  21 . As shown in  FIG. 3A , the side  22   c  of the shielding member  32   a  is flush with the side  21   c  of the electronic component  21 . As shown in  FIG. 3B , the side  22   c  of the shielding member  32   b  protrudes from the side  21   c  of the electronic component  21 . As shown in  FIG. 3D , the left and right sides  22   c  (and/or the front and back sides) of the shielding member  32   d  protrude from the side  21   c  of the electronic component  21 . 
         [0048]    As shown in  FIG. 3C , since the width r′ of the shielding member  32   b  is less than the width t of the electronic component  21 , the shielding member  32   c  partially covers the upper surface  21   a  of the electronic component  21 . 
         [0049]    When the widths r and r′ of the shielding members  32   a ,  32   e ,  32   b  and  32   d  are equal to the width t of the electronic component  21 , the shielding members  32   a ,  32   e ,  32   b  and  32   d  can be placed slightly off a centre of the upper surface  21   a  of the electronic component  21 , such that the upper surface  21   a  of the electronic component  21  is exposed. As shown in  FIG. 3E , the shielding member  32   e  partially covers the upper surface  21   a  of the electronic component  21 . 
         [0050]      FIG. 4  is a cross-sectional view of a package structure  4  in accordance with a third embodiment of the present invention. The third embodiment differs from the first embodiment in that in the third embodiment additional electronic components are included. 
         [0051]    As shown in  FIG. 4 , the package structure  4  further comprises another electronic component  41  disposed on the second surface  22   b  of the shielding member  22 . 
         [0052]    The electronic component  41  is coupled onto the second surface  22   b  of the shielding member  22  via a bonding layer  410 , and the encapsulant  23  also encapsulates the electronic component  41  formed on the second surface  22   b  of the shielding member  22 . 
         [0053]    In an embodiment, the electronic component  41  is an active or a passive component, and is not a low frequency component. 
         [0054]    The carrier  20  is used to carry a plurality of electronic components  21 ,  41 ,  51 ,  61  and  71 , and the shielding member  22  is coupled to one electronic component  21  only. In an embodiment, the electronic component  51  is a conductive circuit, and the other electronic components  61  are passive components. The electronic component  71  is another package unit, and the electronic components  51 ,  61  and  71  are not low frequency components and do not need shielding member mounted thereon. 
         [0055]    The encapsulant  23  encapsulates the electronic components  21 ,  51 ,  61  and  71 . 
         [0056]      FIG. 5  is a cross-sectional view of a package structure  5  in accordance with a fourth embodiment of the present invention. The fourth embodiment differs from the third embodiment in that in the fourth embodiment a plurality of shielding members which are connected to the electronic components, respectively, are further included. 
         [0057]    As shown in  FIG. 5 , the electronic component  51  is a low frequency conductive circuit, and the other electronic components  61  and  71  are not low frequency components. The shielding members  22  and  52  are coupled to the low frequency electronic components  21  and  51 , respectively, via the bonding layers  220  and  520 . 
         [0058]    In an embodiment, the shielding member  52  covers a portion or the entire upper surface  51   a  of the electronic component  51 , and partially or entirely cover the low frequency conductive circuit. 
         [0059]    Moreover, the encapsulant  23  encapsulates the electronic components  21 ,  51 ,  61  and  71 . 
         [0060]      FIG. 6  is a cross-sectional view showing a package structure  6  in accordance with a fifth embodiment of the present invention. The fifth embodiment differs from the third embodiment in that in the fifth embodiment a single shielding member is coupled to a plurality of electronic components. 
         [0061]    As shown in  FIG. 6 , the carrier  20  carries a plurality of electronic components  21 ,  51 ,  61  and  71 , and the electronic component  61  is a low frequency passive component, while the other electronic components  21 ,  51  and  71  are not low frequency components. Therefore, the shielding member  22  is coupled to the low frequency electronic component  61  only. 
         [0062]    Moreover, the encapsulant  23  encapsulates the electronic components  21 ,  51 ,  61  and  71 . 
         [0063]      FIG. 7  is a cross-sectional view showing a package structure  7  in accordance with a sixth embodiment of the present invention. The sixth embodiment differs from the third embodiment in that in the sixth embodiment a single shielding member is coupled to a plurality of different electronic components. 
         [0064]    As shown in  FIG. 7 , the carrier  20  carries a plurality of electronic components  21 ,  51 ,  61  and  71 , the electronic components  21  and  61  are low frequency components, and the single shielding member  72  is coupled to the electronic components  21  and  61 . The other electronic components  51  and  71  are not low frequency components, and no shielding member is formed on the electronic components  51  and  71 . 
         [0065]    In an embodiment, the electronic components  21  and  61  have different heights. In another embodiment, the electronic components  21  and  61 ′ may also have different heights, as shown in FIG.  7 ′. 
         [0066]    Furthermore, the encapsulant  23  encapsulates the electronic components  21 ,  51 ,  61  and  71 . 
         [0067]    In an embodiment, the shielding member can be installed on the electronic component  71  according to practical needs. 
         [0068]    In an embodiment, a portion of the shielding member is exposed from the encapsulant. For example, the second surface  22   b  of the shielding member  22  is flush with the surface  23   a  of the encapsulant  23 ′, as shown in FIG.  2 ′; or the side  22   c  of the shielding member  22  is flush with the side  23   c  of the encapsulant  23 ″, as shown in FIG.  2 ″. 
         [0069]      FIG. 8  is a cross-sectional view showing a package structure  8  in accordance with a seventh embodiment of the present invention. The seventh embodiment differs from the third embodiment in the types of low frequency electronic components. 
         [0070]    As shown in  FIG. 8 , the low frequency electronic component  80  is a packaging substrate, and a shielding member  22  is coupled onto the electronic component  80 . The shielding member  22  carries a non-low frequency electronic component  81 . 
         [0071]    In an embodiment, the non-low frequency electronic component  81  is an active component, or a passive component, such as a resistor, a capacitor and an inductor, and the encapsulant  23  encapsulates the upper surface  80   a  of the low frequency electronic component  80  and the non-low frequency electronic component  81 . 
         [0072]    In addition, the shielding member  22  covers the upper surface  80   a  of the electronic component  80 , without having specific limitations. 
         [0073]    In an embodiment, the low frequency refers to a frequency less than 3 MHz. 
         [0074]    In summary, in a package structure according to the present invention, the direct coupling of the shielding members  22 ,  52  and  72  onto the low frequency electronic components  21 ,  51  and  61  allows the shielding members  22 ,  52  and  72  to be installed inside the encapsulants  23  and  23 ′, rather than installed on the outside of the encapsulants  23  and  23 ′. Therefore, the distance between the shielding member and the interference source is reduced, and an optimal shielding effect for low frequency interference is obtained. Hence, the low frequency electronic components  21 ,  51  and  61  are prevented from generating erroneous signals. 
         [0075]    Further, since the shielding member  22  is in direct contact with the low frequency electronic components  21 ,  51  and  61 , there is no need to shield the side  21   c  of the low frequency electronic components  21 ,  51  and  61 . Therefore, the low frequency electronic components  21 ,  51  and  61  can be well shielded. 
         [0076]    Moreover, the shielding members  22 ,  52  and  72  are installed inside of the encapsulants  23  and  23 ′, and the encapsulants  23  and  23 ′ encapsulate the shielding members  22 ,  52  and  72 . Therefore, the overall height of the package structures  2 ,  3   a - 3   e ,  4 ,  5 ,  6  and  7  can be reduced. 
         [0077]    The present invention has been described using exemplary preferred embodiments. However, it is to be understood that the scope of the present invention is not limited to the disclosed embodiments. On the contrary, it is intended to cover various modifications and similar arrangements. The scope of the claims, therefore, should be accorded the broadest interpretation so as to encompass all such modifications and similar arrangements.