Abstract:
A small-sized communication module package mountable on a main board is of stacked structure including a carrier with an opening in which a thermal conductive layer in contact with a substrate stacked on the carrier is filled. The communication module package further includes a chip electrically bonded to the substrate, received in the opening and encapsulated by the thermal conductive layer, and a metal layer in contact with the thermal conductive layer for enhancing heat dissipation.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    1. Field of the Invention 
         [0002]    The present invention relates generally to a communication module and more particularly, to a small-sized communication module package of stacked structure. 
         [0003]    2. Description of the Related Art 
         [0004]    A communication module is designed for use in an electronic apparatus to provide a wireless communication function. Following market demands, electronic products, such as cell phones, PDAs and etc., are made having compact and multi-function characteristics. Therefore, modern electronic produces are commonly small-sized. To reduce the size, a conventional communication module package adopts stacked package technology. By means of stacking circuit module(s) on a carrier, a communication module package of stacked structure can be made having compact and multi-function characteristics. 
         [0005]    However, when reducing the size of a wireless communication module package, the heat dissipation requirement must be more critical. Conventional package structures for communication module commonly dissipate heat by air. However, the thermal conductivity of air is only about 0.025 W/m·K at room temperature. Because a wireless communication module package is substantially an enclosed structure, it is not in favor of air convection, and heat energy tends to be accumulated inside the package. As a result, conventional communication module packages cannot dissipate heat rapidly, i.e., conventional communication module packages commonly have the drawback of low heat dissipation efficiency. Further, in a conventional communication module package, connections between elements are achieved by means of contact pads only. This connection structure has a weak structural strength. An impact or falling of the communication module package may cause concentration of stress and severe damage. 
         [0006]    Therefore it is desirable to provide a small-sized communication module package that can eliminate the aforesaid problems. 
       SUMMARY OF THE INVENTION 
       [0007]    The present invention has been accomplished under the circumstances in view. It is the primary objective of the present invention to provide a small-sized communication module package, which can provide a good heat dissipation effect and good structural strength. 
         [0008]    To achieve the above-mentioned objective, the small-sized communication module package is mountable on a main board and is of stacked structure comprising a carrier with an opening in which a thermal conductive layer in contact with a substrate stacked on the carrier is filled. The communication module package may further includes a chip electrically bonded to the substrate, received in the opening and encapsulated by the thermal conductive layer, and a metal layer in contact with the thermal conductive layer for enhancing heat dissipation. 
         [0009]    In a first exemplary embodiment of the present invention to be detailedly described hereinafter, the communication module package comprises a carrier having a top bearing surface, a bottom bearing surface for mounting on the main board, and an opening through the top bearing surface and the bottom bearing surface, and a substrate having a bottom surface electrically bonded to the top bearing surface of the first carrier. A thermal conductive layer formed of an electrically insulative and thermally conductive material is filled up the opening of the first carrier. At least one chip is electrically mounted on the bottom surface of the first substrate, received in the opening of the carrier and encapsulated by the thermal conductive layer. A metal layer is attached to the thermal conductive layer and can be in contact with the main board when the communication module package is mounted on the main board. 
         [0010]    In a second exemplary embodiment of the present invention to be detailedly described hereinafter, the communication module package comprises a first carrier, a first substrate, a second carrier and a second substrate stacked one another. The first carrier has an opening in which a first thermal conductive layer is filled and in contact with the first substrate. The second carrier has an opening in which a second thermal conductive layer is filled and in contact with the first and second substrates. The communication module package further comprises at least one chip electrically mounted on the bottom surface of the first substrate, received in the opening of the first carrier and encapsulated by the first thermal conductive, and at least one chip electrically mounted on the top surface of the first substrate, received in the opening of the second carrier and encapsulated by the second thermal conductive layer. A first metal layer is attached to the first thermal conductive layer and can be in contact with the main board when the communication module package is mounted on the main board. A second metal layer is attached to the second thermal conductive layer and in contact with the second substrate. 
         [0011]    The small-sized communication module package of the present invention uses an electrically insulative and thermally conductive material for packaging, improving the heat dissipation effect of the communication module and overcoming the drawback of poor heat dissipation effect of the prior art design. Further, the small-sized communication module package can disperse external impact by means of the thermal conductive layer, eliminating concentration of stress and preventing damage to electrically connecting portions of the contact pads. In other words, the small-sized communication module package of the present invention can provide a good structural strength. 
         [0012]    Further scope of applicability of the present invention will become apparent from the detailed description given hereinafter. However, it should be understood that the detailed description and specific examples, while indicating preferred embodiments of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0013]    The present invention will become more fully understood from the detailed description given herein below and the accompanying drawings which are given by way of illustration only, and thus are not limitative of the present invention, and wherein: 
           [0014]      FIG. 1  is a schematic drawing showing the relationship between the substrate and the carrier of a small-sized communication module package in accordance with a first preferred embodiment of the present invention; 
           [0015]      FIG. 2  is another schematic drawing showing the substrate and the carrier are bonded together; 
           [0016]      FIG. 3  is still another schematic drawing showing that a thermal conductive layer is filled with the opening of the carrier and covers the chips; 
           [0017]      FIG. 4  is still another schematic drawing showing that a metal layer is disposed on the thermal conductive layer; 
           [0018]      FIG. 5  is a sectional view taken along line  5 - 5  of  FIG. 4 ; 
           [0019]      FIG. 6  is a schematic exploded view showing that the small-sized communication module package according to the first preferred embodiment of the present invention is to be installed on a main board; 
           [0020]      FIG. 7  is a schematic perspective assembly view of  FIG. 6 ; 
           [0021]      FIG. 8  is a sectional view taken along line  8 - 8  of  FIG. 7 ; and 
           [0022]      FIG. 9  is a sectional view of a small-sized communication module package in accordance with a second preferred embodiment of the present invention. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0023]    Referring to  FIGS. 1-8 , a small-sized communication module package  10  in accordance with a first preferred embodiment of the present invention is adapted to be mounted on a main board  1 . The communication module package  10  comprises a substrate  20 , a carrier  30 , a thermal conductive layer  40 , and a metal layer  50 . 
         [0024]    The substrate  20  is made by means of SIP (system-in-package) technology, having a top surface  22 , a bottom surface  24  and a plurality of contact pads  28  arranged on the bottom surface  24  around the border of the substrate  20 . In this embodiment, two IC chips  26  are respectively mounted on the top surface  22  and the bottom surface  24 . It is to be easily understood that the communication module package  10  can be designed containing one or more chips  26  of various functions, which can be mounted on the top surface  22  and/or the bottom surface  24  of the substrate  20  simultaneously or individually, depending on the requirement of the communication module package in practice. 
         [0025]    The carrier  30  is stacked on the bottom side of the substrate  20 , having a top bearing surface  32 , a bottom bearing surface  34 , and a plurality of contact pads  36 . The contact pads  36  of the carrier  30  are arranged on the top bearing surface  32  and the bottom bearing surface  34  of the carrier  30 . The contact pads at the top bearing surface  32  are electrically connected to the contact pads at the bottom bearing surface  34 . The contact pads  36  at the top bearing surface  32  are electrically connected to the contact pads  28  at the bottom surface  24  of the substrate  20 . The contact pads  36  at the bottom bearing surface  34  are electrically connectable with the contact pads  2  of the main board  1  when the communication module package  10  is mounted on the main board  1 . The carrier  30  further has an opening  38  cut through the top bearing surface  32  and the bottom bearing surface  34  for receiving the IC chips  26  at the bottom surface  24  of the substrate  20 . 
         [0026]    The thermal conductive layer  40  is formed of an electrically insulative and thermally conductive material and filled up the opening  38  of the carrier  30 . The thermal conductivity layer  40  is in contact with the bottom surface  24  of the substrate  20  and encapsulates the IC chips  26  at the bottom surface  24  of the substrate  20 . The thermal conductive layer  40  has a thermal conductivity greater than 0.2 W/m·K. The thermal conductive layer  40  can be prepared from epoxy resin, silicon resin, silicon-filled epoxy resin, or polyester resin. Preferably, the thermal conductive layer  40  is prepared from epoxy resin that has a thermal conductivity about 0.63 W/m·K. 
         [0027]    The metal layer  50  is covered on the free surface of the thermal conductive layer  40  by means of a coating technique and can be closely attachable to the main board  1  when the communication module package  10  is mounted on the main board  1  to enhance the heat dissipation effect of the thermal conductive layer  40 . 
         [0028]    The method of making the small-sized communication module package  10  according to the first preferred embodiment of the present invention is outlined hereinafter step by step with reference to  FIGS. 1-8 . 
         [0029]    1. At first, apply solder paste on the contact pads  28  at the bottom surface  24  of the substrate  20  and the contact pads  36  at the top bearing surface  32  of the carrier  30  as shown in  FIG. 1 . 
         [0030]    2. Place the carrier  30  on the bottom side of the substrate  20  to attach the contact pads  36  at the top bearing surface  32  of the carrier  30  to the contact pads  28  at the bottom surface  24  of the substrate  20  and to have the IC chips  26  of the substrate  20  be suspended in the opening  38  of the carrier  30 , and then heating the applied solder paste to have the carrier  30  and the substrate  20  be bonded together by the solder paste as shown in  FIG. 2 . 
         [0031]    3. Fill up the opening  38  of the carrier  30  with an electrically insulative and thermally conductive material to form the desired thermal conductive layer  40  that is in contact with the bottom surface  24  of the substrate  20  and that encapsulates the IC chips  26  at the bottom surface  24  of the substrate  20  as shown in  FIG. 3 . 
         [0032]    4. Coat the free surface of the thermal conductive layer  40  with a layer of metal material to form the desired metal layer  50 , as shown in  FIGS. 4 and 5 , thereby finishing the small-sized communication module package  10 . 
         [0033]    When installing small-sized communication module package  10  on the main board  1 , apply solder paste on the contact pads  36  at the bottom bearing surface  34  of the carrier  30  and the contact pads  2  at the main board  1 , and then bond the contact pads  36  at the bottom bearing surface  34  of the carrier  30  to the contact pads  2  at the main board  1 , as shown in  FIGS. 6-8 . 
         [0034]    According to the aforesaid first preferred embodiment of the present invention, the small-sized communication module package  10  uses an electrically insulative and thermally conductive material, which has a thermal conductivity higher than that of air, to cover the bottom surface  24  of the substrate  20  so as to conduct the heat generated by the substrate  20  to the main board  1  for heat dissipation through the heat-dissipative mechanism (not shown) of the main board  1 . 
         [0035]    As a result, the thermal conductive layer  40  forms a heat dissipative path in the communication module package  10  to efficiently exhaust the heat generated by the chips  26 , improving the heat dissipation efficiency of the communication module package and overcoming the drawback of poor heat dissipation effect of the prior art design. Further, the small-sized communication module package  10  can disperse external impact by means of the connection effect of the thermal conductive layer  40  between the substrate  20  and the carrier  30 , eliminating concentration of stress and preventing damage to electrically connecting portions of the contact pads  28 ,  36 . In other words, the communication module package  10  has a characteristic of good structural strength. 
         [0036]      FIG. 9  illustrates a small-sized communication module package  12  in accordance with a second preferred embodiment of the present invention, which is installed on a main board  3 . The small-sized communication module package  12  comprises a first substrate  60 , a first carrier  70 , a first thermal conductive layer  80 , a first metal layer  90 , a second carrier  100 , a second substrate  110 , a second thermal conductive layer  120 , and a second metal layer  130 . 
         [0037]    The first substrate  60  is made by means of SIP (system-in-package) technology, having a top surface  62 , a bottom surface  64  and a plurality of conducting contact pads  68 . In this embodiment, an IC chip  66  is mounted on the bottom surface  64  of the first substrate  60 , and two IC chips  66  are mounted on the top surface  62  of the first substrate  60 . However, it is to be easily understood that the communication module package  12  can be designed containing one or more chips  66  of various functions, which can be mounted on the top surface  62  and/or the bottom surface  64  of the substrate  60  simultaneously or individually, depending on the requirement of the communication module package in practice. The contact pads  68  are respectively arranged on the top surface  62  and bottom surface  64  of the first substrate  60 . 
         [0038]    The first carrier  70  has a top bearing surface  72 , a bottom bearing surface  74 , and a plurality of contact pads  76 . The contact pads  76  of the first carrier  70  are arranged on the top bearing surface  72  and the bottom bearing surface  74 . In addition, the contact pads at the top bearing surface  72  are electrically connected to the contact pads at the bottom bearing surface  74 . The contact pads  76  at the top bearing surface  72  are electrically connected to the contact pads  68  of the bottom surface  64  of the first substrate  60 . The contact pads  76  at the bottom bearing surface  74  are electrically connected to respective contact pads  4  of the main board  3 . The first carrier  70  further has an opening  78  cut through the top bearing surface  72  and the bottom bearing surface  74  for receiving the IC chip  66  at the bottom surface  64  of the first substrate  60 . 
         [0039]    The first thermal conductive layer  80  is formed of an electrically insulative and thermally conductive material and filled up the opening  78  of the first carrier  70 . The thermal conductivity layer  80  is in contact with the bottom surface  64  of the first substrate  60  and encapsulates the IC chips  66  at the bottom surface  64  of the first substrate  60 . The first thermal conductive layer  80  has a thermal conductivity greater than 0.2 W/m·K. The first thermal conductive layer  80  may be prepared from epoxy resin, silicon resin, silicon-filled epoxy resin, or polyester resin. Preferably, the first thermal conductive layer  80  is prepared from epoxy resin that has a thermal conductivity about 0.63 W/m·K. 
         [0040]    The first metal layer  90  is attached to the free surface of the first thermal conductive layer  80  by a coating technique and can be closely attached to the main board  3  when the communication module package  12  is mounted on the main board  3  to enhance the heat dissipation effect of the first thermal conductive layer  60 . 
         [0041]    The second carrier  100  has a top bearing surface  102 , a bottom bearing surface  104 , and a plurality of contact pads  106 . The contact pads  106  of the second carrier  100  are respectively arranged on the top bearing surface  102  and bottom bearing surface  104 . In addition, the contact pads at the top bearing surface  102  are electrically connected to the contact pads at the bottom bearing surface  104 . The contact pads  106  at the bottom bearing surface  104  of the second carrier  100  are electrically connected to the contact pads  68  at the top surface  62  of the first substrate  60 . The second carrier  100  further has an opening  108  cut through the top bearing surface  102  and the bottom bearing surface  104  for accommodating the IC chips  66  at the top surface  62  of the first substrate  60 . 
         [0042]    The second substrate  110  has a top surface  112 , a bottom surface  114  and a plurality of contact pads  118 . In this embodiment, an IC chip  116  is mounted on the top surface  112  of the second substrate  110 . In practice, one or more chips  116  of various functions can be mounted on the top surface  112  and/or the bottom surface  114  of the second substrate  110  simultaneously or individually, depending on the requirement of the communication module package  12 . The contact pads  118  of the second substrate  110  are arranged on the bottom surface  114  of the second substrate  110  and electrically connected to the contact pads  106  at the top bearing surface  102  of the second carrier  100 . 
         [0043]    The second thermal conductive layer  120  is formed of an electrically insulative and thermally conductive material and filled up the opening  108  of the second carrier  100 . The second thermal conductive layer  120  is in contact with the top surface  62  of the first substrate  60  and the bottom surface  114  of the second substrate  110  and encapsulates the IC chips  66  at the top surface  62  of the first substrate  60 . The second thermal conductive layer  120  has a thermal conductivity greater than 0.2 W/m·K. The second thermal conductive layer  120  can be prepared from epoxy resin, silicon resin, silicon-filled epoxy resin, or polyester resin. Preferably, the second thermal conductive layer  120  is prepared from epoxy resin that has a thermal conductivity about 0.63 W/m·K. 
         [0044]    The second metal layer  130  is formed on the second thermal conductive layer  120  by a coating technique and closely attached to the bottom surface  114  of the second substrate  110  to enhance the heat dissipation effect of the second thermal conductive layer  120 . 
         [0045]    According to the aforesaid second preferred embodiment of the present invention, the small-sized communication module package  12  uses an electrically insulative and thermally conductive material, which has a thermal conductivity higher than that of air, to cover the bottom surface  64  and the top surface  62  of the first substrate  60  so as to conduct the heat generated by the first substrate  60  and second substrate  110  to the main board  3  through the first metal layer  90  and second metal layer  130  for heat dissipation through the heat-dissipative mechanism (not shown) of the main board  3 . 
         [0046]    As a result, the thermal conductive layers  80 ,  120  form a heat dissipative path in the communication module package  12  to efficiently exhaust the heat generated by the chips  66 ,  116 , improving the heat dissipation efficiency of the communication module package and overcoming the drawback of poor heat dissipation effect of the prior art design. Further, the small-sized communication module package  12  can disperse external impact by means of the connection effects of the thermal conductive layers  80 ,  120  between the substrates  60 ,  110  and the carriers  70 ,  100 , eliminating concentration of stress and preventing damage to electrically connecting portions of the contact pads  68 ,  76 ,  106 . In other words, the communication module package  12  has a characteristic of good structural strength. 
         [0047]    In conclusion, the present invention provides a small-sized communication module package, which uses an electrically insulative and thermally conductive material for packaging, improving the heat dissipation efficiency of the communication module package and overcoming the drawback of poor heat dissipation effect of the prior art design. Further, the small-sized communication module package can disperse external impact by means of the thermal conductive layer(s), eliminating concentration of stress and preventing damage to electrically connecting portions of the contact pads. 
         [0048]    The invention being thus described, it will be obvious that the same may be varied in many ways. Such variations are not to be regarded as a departure from the spirit and scope of the invention, and all such modifications as would be obvious to one skilled in the art are intended to be included within the scope of the following claims.