Abstract:
Heat dissipation apparatus applies to a package device on a substrate. The package device has an upper surface, a bottom surface, and a sidewall between the upper and bottom surfaces, in which the bottom surface thermally contacts the substrate through multitudes of conductive bumps. For dissipating heat from the bottom surface, the heat dissipation apparatus includes a first heat-dissipating structure contacting a portion of the bottom surface and a second heat-dissipating structure on the upper surface. With the surrounding association of the first and the second heat-dissipating structures, these structures release heats from the sidewall of the die. Such a heat dissipation apparatus is capable of discharging heat at three dimensions, preventing the conductive bumps from collapsing, and enhancing reliability.

Description:
BACKGROUND OF THE INVENTION  
       [0001]     1. Field of the Invention  
         [0002]     The present invention generally relates to heat dissipation apparatus, and more particularly to heat dissipation apparatus for a package device.  
         [0003]     2. Description of the Prior Art  
         [0004]     Following the development of integrated circuit technology, the packing requirement is more and more strict for the IC (integrated circuit), because the packaging technology is directly related to the function of the electronic products. The conventional packaging methods include DIP (Dual In-line Package), QFP (Quad Flat Package), and PFP (Plastic Flat Package). When the frequency of IC exceeds 100 MHz, the conventional packaging method generates a phenomenon called “Cross-Talk”. Furthermore, when the number of pins is larger than 208, the packaging becomes more difficult in the conventional packaging technology. In addition to the QFP technology, the BGA (ball grid array package) technology is the most popular packaging technology if the chip has many pins, such as graphic chips and chip module. Thus, in the present, the BGA technology is the best choice for the chip with a high density, and high performance, and multitudes of pins such as CPU (central processing unit) and south/north bridges chip on/in the motherboard.  
         [0005]     On the other hand, the BGA packaging technology can be classified into five types: PBGA (Plastic BGA) substrate, CBGA (Ceramic BGA) substrate, FCBGA (Flip chip BGA) substrate, TBGA (Tape BGA) substrate, and CDPBGA (Cavity Down PBGA) substrate. Typically, the IC packaging process is packaged from a single IC, which needs a leadframe or substrate, and also include some processes such as the die attach, bonding, molding, or trim and form processes, such that the chip size of the packaged IC is greater than the chip after the IC is packaged. FCBGA located on the IC chip that has a metal gold (Au) or a solder bump thereon, which used to bond with PWB (printed wiring board).  
         [0006]     However, when the operating speed of IC and the density of the pins are increased, the heat is an important factor that affects the reliability of chip, wherein the heat is generated from the RF device has amount of current and high frequency. Thus, an important issue for the development of the device is how to release the heat quickly and effectively.  
       SUMMARY OF THE INVENTION  
       [0007]     According to abovementioned, the present invention provides heat dissipation apparatus that applies to the flip chip or BGA package device, and the adhesive material is not to fill around the conductive bump. Thus, the heat dissipation apparatus is capable of discharging the heat at three dimensions, to increase the discharging area and efficiency.  
         [0008]     According to the reliability of the package device, the present invention provides a heat dissipation apparatus that utilizes a rigid heat-dissipating structure to discharge the heat, and supplies a support for the conductive bumps to prevent the conductive bumps from collapsing.  
         [0009]     According to the abovementioned, one embodiment of the present invention provides a heat dissipation apparatus that applies on a package device on a substrate. The package device has a die and multitudes of conductive bumps. The die has an upper surface, a bottom surface, and a sidewall between the upper surface and the bottom surface, in which the bottom surface contacts the substrate through the multitudes of conductive bumps. The heat dissipation apparatus, for example, a rigid metal ring has a first heat-dissipating structure to release the heat from the portion of bottom surface, in which the first heat-dissipating structure contacts the portion of the bottom surface. The first heat-dissipating structure has two sidewalls, one of two sidewall used to define the circumference is larger than the outline of the sidewall of the die, and another sidewall used to define an opening to contain the overall conductive bumps therein. A second heat-dissipating structure, such as a heat sink located on the upper surface of the die, so as to release the heat from the upper surface, in which the first heat-dissipating structure and the second heat-dissipating structure cooperated to surround the sidewall of a die, and released the heat from the sidewall of a die. Furthermore, the thermally conductive adhesive material filled between the first heat-dissipating structure and second heat-dissipating structure. Such as a heat dissipation apparatus is capable of discharging heat at three dimensions, preventing the conductive bumps from collapsing, and enhancing reliability. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0010]     The foregoing aspects and many of the attendant 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:  
         [0011]      FIGS. 1A  to  1 D are schematic cross-section views of assembling the die on the heat dissipation apparatus of the first embodiment in accordance with the present invention disclosed herein;  
         [0012]      FIG. 2  is a schematic represents the heat dissipation apparatus and the cross-section view of the package device of the second embodiment in accordance with the present invention disclosed herein; and  
         [0013]      FIG. 3  is a schematic represents the heat dissipation apparatus of the third embodiment and the cross-section view of the package device in accordance with the present invention disclosed herein. 
     
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0014]     Some sample embodiments of the invention will now be described in greater detail. Nevertheless, it should be recognized that the present invention can be practiced in a wide range of other embodiments besides those explicitly described, and the scope of the present invention is expressly not limited except as specified in the accompanying claims.  
         [0015]     Referring to  FIG. 1A  to  FIG. 1D , show cross-section views of assembling the die on the heat dissipation apparatus of the first embodiment. Referring to  FIG. 1A , a first heat-dissipating structure is placed on the substrate  10 . In one embodiment, the substrate  10  can be made of any material, in which the surface of substrate  10  can be a thermally conductive surface or include the plurality of thermally conductivie pad that cab be adhered. Then, the first heat-dissipating structure consists of the thermally conductive adhesive layer  12  and the rigid thermally conductive ring  14 , in which the thermally conductive adhesive layer  12  located between the substrate  10  and the thermally conductive ring  14 . The material of the thermally conductive adhesive layer  12  is a dielectric material, and more preferred material is a high thermally conductive material.  
         [0016]     In one embodiment, the thermally conductive ring  14  has an inner wall  34 , a middle wall  35 , and an outer wall  36  in parallel, in which the inner wall  34  defines an opening  44 , the middle wall  35  defines an opening, and an outer wall  36  defines an outline of thermally conductive ring  14 . Furthermore, the middle wall  35  located on the inner wall  34  in parallel and between the inner wall  34  and outer wall  36 , and the opening  45  is larger than the opening  44 . In addition, the thermally conductive ring  14  is made of the thermally conductive material, such as Al (aluminum) or Cu (copper).  
         [0017]     Then, referring to  FIG. 1B , a package device located on the first heat-dissipating structure. In one embodiment, the package device consists of a die  18  (or package body) and multitudes of conductive bumps  16 , in which the die  18  has a bottom surface  38 , an upper surface  48 , and a side wall  58  located between the bottom surface  38  and the upper surface  48 . Moreover, the conductive bumps  16 , such as solder ball or gold bump, located on the bottom surface  38 , and adhered to the substrate  10 . The key feature of the present invention is that the thermally conductive ring  14  contacts the portion of the bottom surface  38  to release the heat from the portion of bottom surface  38 . The overall conductive bumps  16  are disposed within the opening  44  and surrounded by the inner wall  34 . In this embodiment, the die  18  is disposed in the opening  45 . Furthermore, the key feature of this embodiment is that the inner wall  34  of the thermally conductive ring  14  has a L-cross-section and the middle wall  35  that can assist the alignment process of the package device.  
         [0018]     Notability, the inner circumference is defined by the inner wall  34  that is smaller than the outline circumference of the side wall  58 , and the outline circumference is defined by the outer sidewall  36  is larger than the circumference of the side wall  58 , such that the thermally conductive ring  14  can contact the portion of bottom surface  38 . In addition, the total height of the inner wall  34  and the thermally conductive adhesive layer  12  is less than the height of the conductive bumps  16 . For example the total height is 80% of height of the conductive bumps  16 . But the total height is equally to the height of the conductive bumps  16  after re-flow process.  
         [0019]     The one feature of the present invention is that the support is supplied by the height of the inner wall  34  of the thermally conductive ring  14  (when the height of the adhesion layer  12  is very small) that can prevent the conductive bumps  16  from collapsing, reduce the shear loading, underfill, and enhance the reliability and increase the life of the package device. In addition, the height of the outer wall  36  is about equal to the total height of the conductive bumps  16  and the die  18 , thus, the heat for the sidewall  58  of the die  18  that can be released.  
         [0020]     Next, as shown in  FIG. 1C , another thermally conductive adhesive layer  29  filled between the sidewall  58  and the middle wall  35 , and on the upper surface  48 . The thermally conductive adhesive layer  20  is similar to the thermally conductive adhesive layer  12 , which is made of the dielectric material, preferably a material that has a higher thermal conductivity. Thus, the thermally conductive adhesive layer  20  can assist to release the heat from the side wall  58  and the upper surface  48 . Therefore, the thermally conductive adhesive layer  20  can use as a part device of the heat dissipation apparatus.  
         [0021]     Then, as shown in FIG. ID, a second heat-dissipating structure  22  located on the thermally conductive adhesive layer  20 , that is, the second heat-dissipating structure  22  are disposed on the upper surface  48  to release the heat from the upper surface  48 . The second heat-dissipating structure  22 , such as a rigid rectangular heat sink, which is made of the thermally conductive material, such as Al or Cu. In this embodiment, the second heat-dissipating structure  22  has an outline circumference equal to the outline circumference of the thermally conductive ring  14 . Thus, the second heat-dissipating structure and the thermally conductive ring  14  can be inlaid completely, and the package device is surrounded therein. In alternative embodiment (not shown in FIGs), the height of an outer wall  36  of the thermally conductive ring  14  is equal to the total height of the second heat-dissipating structure  22 , die  18 , and the conductive bumps  16 , such that the second heat-dissipating structure  22  has an outline circumference that is equal to the circumference of the side wall  58  of the die  18 . Similarly, the second heat-dissipating structure  22  and the thermally conductive ring  14  can be completely inlaid, so as to surround the package device therebetween.  
         [0022]     Next,  FIG. 2  is a schematic, which represents the heat dissipation apparatus of the second embodiment and the cross-section view of the package device. The difference betweem the first embodiment is that the rectangular thermally conductive ring  14  does not have a middle wall  35  and the height  36  of the outer wall  36  is equal to the inner wall  34 . Then, the second heat-dissipating structure  22 , such as an inverse U-type heat sink has an inner wall  49  which defines the opening to contain the die  18  therein. The circumference of the inner wall  49  is larger than the circumference of the side wall  58  of the die  18 . Furthermore, the side wall  58  of die  18  is surrounded by the inner wall  49  of the second heat-dissipating structure  22 , so as to release the heat from the side wall  58 . At the same time, the second heat-dissipating structure  22  releases the heat from the upper surface  48  of the die  18 . Notability, in second embodiment, the die  18  can be first placed in the opening that defined by the inner wall  49  of the second heat-dissipating structure  22 , so as to the second heat-dissipating structure  22  also can assist the alignment process of the package device.  
         [0023]     Next,  FIG. 3  represents the third embodiment of the heat dissipation apparatus and the cross-section view of the package device. The different from the first embodiment is that the thermally conductive ring  14  has a middle wall  35 , which the height of the middle  35  or outer wall  36  is higher than the inner wall  34 , but the height is smaller than the total height of the die  18  and the thermal conductive bumps  16 , so as to release the heat from the portion of the sidewall  58 . However, the difference between the second embodiment is that the second heat-dissipating structure  22  has an inner wall  49  and the opening defined by the inner wall  49  to contain the portion of the die  18 . The second heat-dissipating structure  22  also can release the heat from the portion of the side wall  58 , even if the height of the inner wall is shorter than the die  18 . Thus, in the third embodiment, the thermally conductive ring  14  and the second heat dissipating structure  22  (also includes the thermally conductive adhesive layer  20 ) can release the heat from the overall sidewall  58 . It is noted that the shape of the thermally conductive ring  14  is a sample for this embodiment, but the embodiment is not in this limitation.  
         [0024]     According to the abovementioned, the heat dissipation apparatus of this invention can dissipate the heat from three dimensions: upper surface, bottom surface, and the sidewall, have good heat dissipating efficiency that compares with the conventional heat sink, and prevents the conductive bumps from collapsing, and reduces the shear loading, so as to apply on the flip-chip or BGA package device.  
         [0025]     Although specific embodiments have been illustrated and described, it will be obvious to those skilled in the art that various modifications may be made without departing from what is intended to be limited solely by the appended claims.