Patent Publication Number: US-2012025215-A1

Title: Semiconductor package with heat dissipating structure

Description:
BACKGROUND 
     1. Technical Field 
     The present disclosure relates to semiconductor packages, and more particularly to a light emitting element package having a heat dissipating structure. 
     2. Description of Related Art 
     Generally, a light emitting element package includes a substrate, a semiconductor chip, such as a light emitting diode (LED) chip, attached on the substrate and a heat dissipating member fixed on the substrate. The heat generated by the LED chip is conducted to the heat dissipating member through the substrate and is dissipated to an exterior environment through the heat dissipating member. However, because the thermal conductivity of the substrate is usually much less than the heat dissipating member, the heat dissipation efficiency of the light emitting element package is somehow compromised. 
     Therefore, it is desirable to provide a semiconductor package which can overcome the above-mentioned shortcomings. 
    
    
     
       BRIEF DESCRIPTION OF THE FIGURE 
       Many aspects of the embodiments can be better understood with references to the following drawings. The components in the drawings are not necessarily drawn to scale, the emphasis instead being placed upon clearly illustrating the principles of the embodiments. Moreover, in the drawings, like reference numerals designate corresponding parts throughout the several views. 
         FIG. 1  is a schematic top view of a semiconductor package according to one embodiment of the present disclosure. 
         FIG. 2  is a cross-sectional view of the semiconductor package taken along line II-II of  FIG. 1 . 
         FIG. 3  is a cross-sectional view of the semiconductor package taken along line III-III of  FIG. 1 . 
     
    
    
     DETAILED DESCRIPTION 
     Referring to  FIGS. 1 and 2 , a semiconductor package  1  includes a substrate  10 , at least one semiconductor chip attached on the substrate  10 , a heat dissipating member  14  fixed on the substrate  10 , and a number of electrodes  16  formed in the substrate  10 . In this embodiment, the at least one semiconductor chip includes a number of LED chips  12 . 
     The substrate  10  is made of electrically insulating material with a high thermal conductivity, such as beryllium oxide (BeO), carborundum (SiC), aluminum nitride (AlN), alumina (AlO), or high-temperature plastic. The substrate  10  includes an upper surface  100 , a lower surface  102  parallel and opposite to the upper surface  100 , and a side surface  104 . The side surface  104  perpendicularly connects the peripheries of the upper and lower surfaces  100 ,  102 . The substrate  10  defines a first through hole  106  perpendicularly extending from a center of the upper surface  100  to the lower surface  102 . The substrate  10  also defines a number of second through holes  108  perpendicularly extending from the upper surface  100  to the lower surface  102 . The second through holes  108  are arranged in two rows and correspondingly located at opposite sides of the first through hole  106 . In this embodiment, the second through holes  108  in each side are arranged in a line and equidistantly spaced from each other. 
     Each electrode  16  penetrates the substrate  10  via one corresponding second through hole  108  and then extends transversely from the lower surface  102  to the adjacent side surface  104 . 
     Referring to  FIGS. 2 and 3 , the heat dissipating member  14  is configured to dissipate the heat from the LED chips  12  to an exterior environment. In this embodiment, the heat dissipating member  14  is made of metal with high thermal conductivity and high reflectivity, such as copper, aluminum, iron, or an alloy thereof. The heat dissipating member  14  includes a dissipating portion  140 , a conducting portion  142 , and a fastening portion  144 . The dissipating portion  140  includes a top surface  140   a , a bottom surface  140   b  opposite to the top surface  140   a , and a side wall  140   c  connecting an outer periphery of the top and bottom surfaces  140   a ,  140   b . A fin set  140   d  including a plurality of fins is formed on the side wall  140   c  to increase the heat dissipating area of the dissipating portion  140 . In this embodiment, each fin of the fin set  140   d  is extended in parallel with the top and bottom surfaces  100 ,  102 . The bottom surface  140   b  of the dissipating portion  140  tightly engages with the upper surface  100  of the substrate  10  and occupies a quite large portion of the upper surface  100  (as best seen from  FIG. 1 ). 
     The dissipating portion  140  defines a receiving through hole  141  extending from a center of the top surface  140   a  to the bottom surface  140   b . The receiving through hole  141  defines an upper opening  141   a , a lower opening  141   b , and an inner wall  141   c  connecting the upper and lower openings  141   a ,  141   c . In this embodiment, the upper opening  141   a  is wider than the lower opening  141   b  and the inner wall  141   c  is a downwardly inwardly inclined surface. 
     The conducting portion  142  is an elongated metal sheet and includes a first surface (i.e., top surface)  142   a  and a second surface (i.e., bottom surface)  142   b  opposite to the first surface  142   a . In this embodiment, the conducting portion  142  extends along a diametrical direction of the lower opening  141   b . Two opposite ends of the conducting portion  142  are correspondingly connected to the periphery of the lower opening  141   b . In this embodiment, the second surface  142   b  tightly engages with the upper surface  100  of the substrate  10  and is coplanar with the bottom surface  140   b  of the dissipating portion  140 . 
     The fastening portion  144  is configured in inverted-“T” shape and includes a connecting pole  144   a  and a stopper  144   b . One end of the connecting pole  144   a  connects a center of the conducting portion  142  at the second surface  142   b . The stopper  144   b  is formed on the other end of the connecting pole  144   a  far from the second surface  142   b.    
     In assembly, the dissipating portion  140  is attached to the substrate  10  with the bottom surface  140   b  engaging with the upper surface  100 . The connecting pole  144   a  is received in the first through hole  106  and the stopper  144   b  abuts against the lower surface  102  of the substrate  10  to prevent the heat dissipating member  14  from moving relative to the substrate  10 . The electrodes  16  penetrate the substrate  10  via the second through holes  108  and are exposed upwardly through the upper surface  100  of the substrate  10  at opposite sides of the conducting portion  142 . In this embodiment, the dissipating portion  140 , the conducting portion  142 , the fastening portion  144 , and the substrate  10  are formed together through low temperature co-fired process. The dissipating portion  140 , the conducting portion  142  and the fastening portion  144  are integrally formed as a single piece. 
     The LED chips  12  are mounted on the first surface  142   a  of the conducting portion  142 . Each LED chip  12  is electrically connected to one pair of electrodes  16  exposed at opposite sides of the conducting portion  142  via two golden wires  13 . Heat generated by the LED chip  12  is conducted to the dissipating portion  140  through the conducting portion  142  and is dissipated through the fin set  140   d  of the dissipating portion  140 . Because the conducting portion  142  and the dissipating portion  140  are integrally made of metal with high thermal conductivity, the efficiency of the heat dissipating efficiency of the semiconductor package  1  can be greatly improved. 
     It is understood that an encapsulation material  15  with high light perviousness can be filled in the receiving through hole  141  to modulate the characteristics of light generated by the LED chips  12 . 
     While various embodiments have been described, it is to be understood that the invention is not limited thereto. To the contrary, various modifications and similar arrangements (as would be apparent to those skilled in the art) are intended to also be covered. Therefore, the scope of the appended claims should be accorded the broadest interpretation so as to encompass all such modifications and similar arrangements.