Abstract:
A light-emitting diode chip package body with an excellent heat dissipation performance and a low manufacturing cost, and a packaging method of the same are disclosed. A LED chip package body is provided, the LED chip package body comprising: a LED chip having an electrode-side surface and at least two electrodes mounted on said electrode-side surface; an electrode-side insulating layer formed on said electrode-side surface of said LED chip and formed with a plurality of through-holes registered with corresponding said electrodes; a highly heat-dissipating layer formed in each of said through-holes of said insulating layer on said electrode-side surface; and a highly heat-conducting metal layer formed on said highly heat-dissipating layer in each of said through-holes.

Description:
RELATED APPLICATIONS 
       [0001]    This application claims priority to Taiwanese Patent Application No. 97118327 filed on May 19, 2008, which is incorporated herein by reference in its entirety. 
       FIELD OF THE INVENTION 
       [0002]    The present invention relates to a light-emitting diode chip, and more particularly, to a light-emitting diode chip package body with an excellent heat dissipation performance and a low manufacturing cost, and a method for manufacturing the same. 
       BACKGROUND OF THE INVENTION 
       [0003]      FIG. 19  is a schematic side view showing a conventional light-emitting diode (LED) chip package body.  FIG. 20  is a schematic view showing the bin distribution of light-emitting diode chip package bodies in which the LED chips used have the same wavelength and same brightness. 
         [0004]    Referring to  FIG. 19 , the conventional light-emitting diode (LED) chip package body includes an LED chip  91  mounted on a lead frame  90 , and an lens  92  formed on the lead frame  90  so as to cover the LED chip  91 . 
         [0005]    The electrodes (not shown) of the LED chip  91  are connected electrically to the corresponding legs  900  of the lead frame  90  via wires  93 . 
         [0006]    It should be noted that a fluorescent layer  94  is formed on an electrode-side surface of the LED chip  91 . The formation of the layer  94  is achieved by the following steps: coating the electrode-side surface of the LED chip  91  with liquid fluorescent layer material; and curing the liquid fluorescent layer material by baking process so as to form the fluorescent layer  94 . 
       SUMMARY OF THE INVENTION 
       [0007]    However, the formation of the fluorescent layer  94  has the following drawbacks: 
         [0008]    Uneven thickness—flowing of the liquid fluorescent layer material in all directions may occur before the baking process, therefore, the thickness of the fluorescent layer formed on each LED chip  91  will be different. 
         [0009]    Different area—as mentioned above, the area of the fluorescent layer formed on each LED chip  91  will therefore be different. 
         [0010]    Different shape—as mentioned above, the shape of the fluorescent layer formed on each LED chip  91  will therefore also be different. 
         [0011]    Relative position offset—as mentioned above, the relative position of the fluorescent layer formed on each LED chip  91  to the corresponding LED chip  91  will therefore be different. 
         [0012]    Due to the aforementioned drawbacks, the LED chip package bodies will therefore be classified to many bins, although the LED chips used in the LED chip package bodies have the same brightness and the same wavelength. 
         [0013]    On the other hand, since the sectional area of the wire  93  is too small, the heat generated by the LED chip  91  is hard to dissipate via the legs  900  of the lead frame  90 , which in turn lower the efficiency of the LED chip package body. 
         [0014]    The object of the present invention is to provide a light-emitting diode chip package body with an excellent heat dissipation performance and a low manufacturing cost, and a packaging method of the same. 
         [0015]    According to one aspect of the present invention, a LED chip package body is provided, the LED chip package body comprising: a LED chip having an electrode-side surface and at least two electrodes mounted on said electrode-side surface; an electrode-side insulating layer formed on said electrode-side surface of said LED chip and formed with a plurality of through-holes registered with corresponding said electrodes; a highly heat-dissipating layer formed in each of said through-holes of said insulating layer on said electrode-side surface; and a highly heat-conducting metal layer formed on said highly heat-dissipating layer in each of said through-holes. 
         [0016]    According to another one aspect of the present invention, a method for manufacturing a LED chip package body is provided, the method comprising the steps of: preparing a LED wafer having a plurality of LED chips, each of said LED chips having a main light-emitting surface, said main light-emitting surfaces of said LED chips cooperatively serving as a main light-emitting surface of said LED wafer; forming a light-emitting surface-side insulating layer on said main light-emitting surface of said LED wafer; forming a plurality of vias each reaching said main light-emitting surface of a corresponding one of said LED chips in said insulating layer; and forming a fluorescent layer in each of said vias on said main light-emitting surface of said LED chip. 
         [0017]    According to still another one aspect of the present invention, a LED chip package body is provided, the LED chip package body comprising: a pair of electrode terminals; and a LED chip having a first electrode-side surface on which a first electrode is formed and a second electrode-side surface on which a second electrode is formed, said first and second electrodes having opposite conductivity, said LED chip supported by said electrode terminals in a manner that said electrodes on said first and second electrode-side surfaces electrically contact with contact of corresponding electrode terminals, said electrode-side surface of said LED chip coated with a diamond-like film. 
         [0018]    According to yet another one aspect of the present invention, a light-emitting module is provided, the light-emitting module comprising: a light-emitting assembly including an elongated printed circuit board on which a plurality of LED chip package bodies, as described above, is mounted in flip-chip manner; and a light-guiding assembly including a diffusion plate mounted on said printed circuit board, said diffusion plate having a surface which faces said printed circuit board and which is formed with a plurality of recess portions adapted to accommodate corresponding said LED chip package bodies on said printed circuit board. 
         [0019]    According to another one aspect of the present invention, a method for manufacturing a LED chip package body is provided, the method comprising the steps of: providing a LED wafer having a plurality of LED chips, each of said LED chips having an electrode-side surface and at least two electrodes mounted on said electrode-side surface, said electrode-side surfaces of said LED chips cooperatively serving as an electrode-side surface of said LED wafer; forming an electrode-side insulating layer on said electrode-side surface of said LED wafer, said electrode-side insulating layer being patterned so as to form with a plurality of through-holes each registered with a corresponding one of said electrodes of said LED chips; forming a highly heat-dissipating layer on said electrode-side insulating layer so as to cover said electrodes of said LED chips exposed by said through-holes of said insulating layer; forming a first metal layer on said highly heat-dissipating layer; forming a second metal layer on said first metal layer; and forming a third metal layer on said second metal layer. 
         [0020]    The above and other features of the invention including various novel details of construction and combinations of parts, and other advantages, will now be more particularly described with reference to the accompanying drawings and pointed out in the claims. It will be understood that the particular method and device embodying the invention are shown by way of illustration and not as a limitation of the invention. The principles and features of this invention may be employed in various and numerous embodiments without departing from the scope of the invention. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0021]    In the accompanying drawings, reference characters refer to the same parts throughout the different views. The drawings are not necessarily to scale; emphasis has instead been placed upon illustrating the principles of the invention. Of the drawings: 
           [0022]      FIG. 1  is a schematic sectional view illustrating a light-emitting diode chip package body according to a first embodiment of the present invention; 
           [0023]      FIGS. 2 to 3  are schematic sectional views illustrating a method for manufacturing the light-emitting diode chip package body shown in  FIG. 1 ; 
           [0024]      FIG. 4  is a schematic sectional view illustrating a light-emitting diode chip package body according to a second embodiment of the present invention; 
           [0025]      FIGS. 5 to 7  are schematic sectional views illustrating a method for manufacturing the light-emitting diode chip package body shown in  FIG. 4 ; 
           [0026]      FIGS. 8 and 9  are schematic diagrams illustrating the state that each via exposes the main light-emitting surfaces of two or more LED chips; 
           [0027]      FIG. 10  is a schematic sectional view illustrating an alternative of the light-emitting diode chip package body according to the second preferred embodiment of the present invention; 
           [0028]      FIG. 11  is a schematic sectional view illustrating an alternative of said light-emitting diode chip package body according to the second embodiment of the present invention; 
           [0029]      FIGS. 12(   a ) and  12 ( b ) are schematic diagrams illustrating a light-emitting diode chip package body according to a third preferred embodiment of the present invention; 
           [0030]      FIGS. 13(   a ) and  13 ( b ) are schematic diagrams illustrating an alternative of the light-emitting diode chip package body according to the third preferred embodiment of the present invention; 
           [0031]      FIGS. 14 to 16  are schematic diagrams illustrating a light-emitting module using the light-emitting diode chip package body of the present invention; 
           [0032]      FIG. 17  is a schematic sectional diagram illustrating an alternative of the light-emitting diode chip package body according to the second embodiment of the present invention; 
           [0033]      FIG. 18  is a schematic diagram illustrating a back-light module using the light-emitting diode chip package body shown in  FIG. 17 ; 
           [0034]      FIG. 19  is a schematic diagram illustrating a conventional light-emitting diode chip package body; 
           [0035]      FIG. 20  is a schematic view showing the bin distribution of light-emitting diode chip package bodies in which the LED chips used have the same wavelength and same brightness; 
           [0036]      FIG. 21  is a schematic diagram illustrating a light-emitting diode chip package body according to a fourth preferred embodiment of the present invention; and 
           [0037]      FIG. 22  is a schematic sectional diagram illustrating an alternative of the second preferred embodiment of the present invention. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0038]    Preferred embodiments of the present invention will be described below with reference to the accompanying drawings. 
         [0039]    It should be noted that the same numeral is used to indicate the same element throughout the whole specification. Furthermore, the elements are not drawn to scale so as to clearly show the features of the present invention. 
         [0040]      FIG. 1  is a schematic sectional view showing a light-emitting diode (LED) chip package body according to a first embodiment of the present invention, and  FIGS. 2 and 3  are schematic sectional views showing a method for manufacturing the LED chip package body shown in  FIG. 1 . 
         [0041]    Referring to  FIGS. 1 to 3 , an electrode-side insulating layer  2  is formed on an electrode-side surface W 10  of a LED wafer W having a plurality of LED chips  1 . Each of the LED chips  1  has an electrode-side surface  10  on which at least two electrodes  11  are mounted. The electrode-side surfaces  10  of the LED chips  1  cooperatively serve as the electrode-side surface W 10  of the LED wafer W. The insulating layer  2  is formed with a plurality of through-holes  20  which expose the corresponding electrodes  11  of the LED chips  1  of the LED wafer W. A highly heat-dissipating layer  30  and a highly heat-conducting metal layer  31  formed on the highly heat-dissipating layer  30  are sequentially formed in each of the through-holes  20  in this order. It should be noted that the layers  30 , 31  can be formed by a sputtering process followed by a chemical mechanical polishing (CMP) process which removes the parts of the layers  30 , 31  on the insulating layer  2 . 
         [0042]    In the present embodiment, the highly heat-dissipating layer  30  is formed of a material having a heat-dissipating coefficient of greater than 400 Watts per meter-Kelvin (W/(m·k)) such as 400 W/(m·k) to 700 W/(m·k) provided by pyrolytic graphite, or a material having a heat-dissipating coefficient of 900 W/(m·k) to 1200 W/(m·k) such as diamond-like carbon. On the other hand, the metal layer  31  may be composed of a Ni layer and an Au layer, or an Al layer and a Cu layer, as shown in  FIG. 11 . Alternatively, the metal layer  31  is composed of a Cu layer. Alternatively, the metal layer  31  may be composed of any suitable metal layer or alloy layer thereof, such as Al, AlN 3 , Cu, BN3, etc. 
         [0043]    Subsequently, a plurality of grooves  13  is formed on a light-emitting surface W 12  opposed to the electrode-side surface W 10  of the LED wafer W along the corresponding cutting lines CL. 
         [0044]    Then, as shown in  FIG. 3 , a fluorescent layer  41  and a protection layer  42  are sequentially formed on the surface W 12  of the LED wafer W. 
         [0045]    Afterwards, the LED chip package body according to the first embodiment of the present invention as shown in  FIG. 1  is obtained after a cutting process is performed on the LED wafer W. Since the side surfaces of the LED chip  1  are mostly covered with the fluorescent layer  41 , the influence of the light from the side surface on which no fluorescent layer is formed on the color of the main light emitted from the LED chip  1  can be decreased. 
         [0046]      FIG. 4  is a schematic sectional view showing a LED chip package body according to a second embodiment of the present invention, and  FIGS. 5 to 7  are schematic sectional views showing a method for manufacturing the LED chip package body shown in  FIG. 4  in manufacturing steps. 
         [0047]    It should be noted that since the formations of the insulating layer  2 , the highly heat-dissipating layer  30  and the highly heat-conducting metal layer  31  are as same as those described in the first embodiment, the detailed description thereof is thus omitted. 
         [0048]    Referring to  FIGS. 4 to 7 , a light-emitting surface-side insulating layer  4  is formed on the main light-emitting surface W 12  of the LED wafer W. A plurality of vias  40  reaching the main light-emitting surface  12  (W 12 ) of the corresponding LED chips  1  is formed in the insulating layer  4 . A fluorescent layer  41  is formed in each via  40 . 
         [0049]    Next, a transparent protection layer  42  is formed on the surface of the insulating layer  4  and the fluorescent layer  41 . Then, as shown in  FIG. 4 , the LED chip package body according to the second embodiment of the present invention is obtained after a cutting process. 
         [0050]    In the aforementioned description, although each via  40  exposes the main light-emitting surface  12  of a corresponding one of the chips, however, each via  40  can expose the main light-emitting surfaces  12  of two or more chips. Namely, each via  40  can expose 2×2, 3×3, 4×4, 5×5 . . . chips, as shown in  FIGS. 8 and 9 . 
         [0051]    The LED chip package bodies manufactured by the method of the present invention will emit the light with same wavelength and same brightness, since the area A 1 , A 2 , A 3 , . . . , An (see  FIG. 5 ) and the thickness D 1 , D 2 , D 3 , . . . , Dn (see  FIG. 7 ) of the fluorescent layer  41  of the LED chips are the same and thus, high yield rate can be achieved. Further, the relative position of the fluorescent layer  41  formed on the light-emitting surface  12  of each LED chip  1  with respect to the corresponding LED chip  1  is same, the shape of the fluorescent layer  41  is same, and thus the aforementioned drawbacks associated with the conventional LED chip package body can be prevented. 
         [0052]    Further, the height of the fluorescent layer  41  in the present invention depends on the height of the insulating layer  4 . Therefore, the difference between the height of the fluorescent layer  41  in theory and the actual height of the fluorescent layer  41  can be suitably controlled. 
         [0053]    Referring to  FIG. 10 , a solder ball  32  can be selectively formed on the metal layer  31 . 
         [0054]    Accordingly, the heat generated by the LED chip  1  can be quickly and efficiently dissipated because of the high heat conducting coefficient of the highly heat-dissipating layer  30  and the highly heat-conducting metal layer  31 . 
         [0055]      FIGS. 12(A) and 12(B)  are schematic view showing a LED chip package body according to another embodiment of the present invention. 
         [0056]    Referring to  FIGS. 12(A) and 12(B) , the LED chip package body includes a pair of terminals  51 , 52 , a LED chip  1  supported by the terminals  51 , 52 , a fluorescent layer  6  covering the LED chip  1 , a reflector  7 , and an lens  8 . 
         [0057]    The LED chip  1  has a first electrode-side surface  13  on which a first electrode  130  is formed, and a second electrode-side surface  14  on which a second electrode  140  is formed. The first electrode  130  and the second electrode  140  have opposite electrical polarity. The LED chip  1  is supported by the terminals  51 , 52  in the manner that the electrodes  130  and  140  on the first and second electrode side surfaces  13  and  14  of the LED chip  1  is in contact with the corresponding terminals  51 , 52 . The surfaces  13 , 14  of the LED chip  1  is coated with a diamond-like carbon film  15 . Therefore, heat inside the lens  8  can be efficiently dissipated through the terminals  51 , 52 . 
         [0058]    Referring to  FIG. 13(A) and 13(B) , an alternative of the LED chip package body shown in  FIG. 12(A)  is shown. The difference between this alternative and the LED chip package body shown in  FIG. 12(A)  is that a fluorescent layer  16  is further coated on the diamond-like carbon film  15  such that the fluorescent layer  6  shown in  FIG. 12(A)  can be omitted. 
         [0059]      FIG. 14  is a schematic partial exploded view showing a light-emitting module, and  FIG. 15  is a schematic assembly view showing the light-emitting module shown in  FIG. 14 . 
         [0060]    Referring to  FIG. 14 , the light-emitting module includes a light-emitting assembly and a light-guiding assembly. The light-emitting assembly includes an elongated printed circuit board  100 . A plurality of LED chip package bodies  200  is mounted on the printed circuit board  100  in Flip Chip manner. A fluorescent layer  201  is coated on the main light-emitting surface of each of the LED chip package bodies  200 . A plurality of inverse-T shape though-holes  101  is formed in the printed circuit board  100 . 
         [0061]    The light-guiding assembly includes a diffusion plate  300 . A plurality of recess portions  301  which is adapted to accommodate the corresponding LED chip package bodies  200  on the printed circuit board  100  and a plurality of hooks  302  are formed on a surface of the diffusion plate  300  facing the printed circuit board  100 . 
         [0062]    As shown in  FIG. 15 , when the hooks of the diffusion plate  300  are engaged with the corresponding though-holes  101  of the printed circuit board  100 , the LED chip package bodies  200  on the printed circuit board  100  are accommodated in the corresponding recess portions  301 , and the light emitted from the LED chip package bodies  200  transfer through the diffusion plate  300 . 
         [0063]    It should be noted that a fluorescent layer  303  (see  FIG. 16 ) can be formed on an inner surface of each of the recess portions  301 . As such, the fluorescent layer on the LED chip package body  200  can be omitted. Alternatively, the fluorescent layer  303  and the fluorescent layer on the LED chip package body  200  can exist simultaneously, so as to prevent the disadvantage of light emitting from the side surface on which no fluorescent layer is formed. 
         [0064]    Referring now to  FIG. 17 , unlike to the second embodiment, no insulating layer is formed on the main light-emitting surface  12  of the LED chip  1  in the present embodiment, the fluorescent layer  41  is formed directly on the main light-emitting surface  12  of the LED chip  1 . 
         [0065]      FIG. 18  is a schematic perspective view showing the light-emitting module employing the LED chip package bodies shown in  FIG. 17 . 
         [0066]    As shown in  FIG. 18 , the light-emitting module includes a printed circuit board  100 , a plurality of LED chip package bodies  200 , and a plurality of caps  400  doped with fluorescent powder. The LED chip package bodies  200  shown in  FIG. 17  are mounted electrically on the printed circuit board  100 . A tapered through-hole  401  is formed in each cap  400 . The caps  400  are mounted on the printed circuit board  100  such that each of the LED chip package bodies  200  is surrounded by the wall confining the through-hole  401  of a corresponding one of the caps  400 . As such, the light emitted from the side surface of the LED chip package body  200  will excite the fluorescent powder in the cap  400  so as to prevent the disadvantage of light emitting from the side surface on which no fluorescent layer is formed. 
         [0067]    Referring to  FIG. 21 , a LED chip  1  is mounted electrically on a substrate S. The LED chip  1  has a first surface  10  on which a first electrode  12  is formed, and a second surface  11  on which a second electrode (not shown) is formed. The LED chip  1  is mounted on a mounting surface  20  of the substrate S via a conductor layer  3  such that the second electrode of the LED chip  1  is connected electrically to the corresponding electrical contact (not shown) on the mounting surface  20  of the substrate S. 
         [0068]    The conductor layer  3  includes a copper layer  32  formed on the mounting surface  20  of the substrate S, a gold layer  31  on the copper layer  32 , and a solder layer  30  on the gold layer  31 . 
         [0069]    The copper layer  32  is connected to the mounting surface  20  of the substrate S with laser welding method or ultrasonic method. 
         [0070]    The gold layer  31  is connected to the copper layer  32  with laser welding method. 
         [0071]    The solder layer  30  is connected to the gold layer  31  with reflow method. 
         [0072]    The first electrode  12  of the LED chip  1  is connected electrically to the conducting contact  21  on the mounting surface  20  of the substrate S. Each conducting contact  21  includes a copper layer  212  formed on the mounting surface  20  of the substrate S, a gold layer  211  on the copper layer  212 , and a solder layer  210  on the gold layer  211 . 
         [0073]    Referring to  FIG. 22 , unlike to the first embodiment of the present invention, the highly heat-conducting metal layer  31  includes a copper layer  310  formed on the highly heat-dissipating layer  30  which is formed from pyrolytic graphite. The highly heat-dissipating layer  30  and the copper layer  310  can be formed by sputtering method. It should be noted that the removal of parts of the highly heat-dissipating layer  30  and the highly heat-conducting metal layer  31  can be achieved by a CMP (Chemical Mechanical Polishing) process. 
         [0074]    The metal layer  31  further includes an Au layer  311  on the copper layer  310  and a solder layer  312  on the Au layer  311 . 
         [0075]    While this invention has been particularly shown and described with references to preferred embodiments thereof, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the scope of the invention encompassed by the appended claims.