Abstract:
Disclosed herein is a structure of an opto-electronic package having a Si-substrate. Si-substrates are manufactured in batch utilizing micro-electromechanical processes or semiconductor processes, so that these Si-substrates are made with great precision and full of varieties. Based on the material characteristic of the Si-substrate, and the configuration of the components, such as the connecters, opto-electronic devices, depressions, solder bumps, etc., the present invention can improve the optical effect, the heat dissipating effect, and the reliability of the structure of opto-electronic package, and simplifies the complexity of the structure of opto-electronic package.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    1. Field of the Invention 
         [0002]    The present invention generally relates to the field of opto-electronic package structures, and more particularly, to an opto-electronic package structure formed by the micro-electromechanical processes or the semiconductor processes. 
         [0003]    2. Description of the Prior Art 
         [0004]    In recent years, a new application field of high illumination light emitting diodes (LEDs) has been developed. Different from a common incandescent light, a cold illumination LED has the advantages of low power consumption, long device lifetime, no idling time, and quick response speed. In addition, since the LED also has the advantages of small size, vibration resistance, suitability for mass production, and ease of fabrication as a tiny device or an array device, it has been widely applied in display apparatuses and indicating lamps used in information, communication, and consumer electronic products. The LEDs are not only utilized in outdoor traffic signal lamps or various outdoor displays, but are also very important components in the automotive industry. Furthermore, the LEDs work well in portable products, such as cellular phones and as backlights of personal data assistants. These LEDs have become necessary key components in the highly popular liquid crystal displays because they are the best choice when selecting the light source of the backlight module. 
         [0005]    Please refer to  FIG. 1  and  FIG. 2 .  FIG. 1  is a schematic top view diagram showing a prior art surface mount device (SMD) LED package structure  10 , and  FIG. 2  is a cross section diagram illustrating the prior art SMD LED package structure  10  along  1 - 1  ′ line shown in  FIG. 1 . As shown in  FIG. 1  and  FIG. 2 , an SMD LED package structure  10  comprises a cup-structure substrate  12 , a lead frame  14 , an opto-electronic device  16 , conducting wires  18  and  20 , and a sealant  22 . As a semiconductor device comprising a positive electrode and a negative electrode (not shown), the opto-electronic device  16  is illuminated by receiving power from an external voltage source and connected to the lead frame  14  by the conducting wires  18  and  20 . Situated in the cup-structure substrate  12 , the lead frame  14  is extended to the outer surface of the cup-structure substrate  12 , which will be electrically connected to a printed circuit board (PCB)  24 . 
         [0006]    In order to construct the prior art LED package  10 , the cup-structure substrate  12  should be completed first, and then the sealant  22  covers the opto-electronic device  16  by means of molding or sealant injection. After the construction of the prior art LED package  10  is completed, at least a surface mounting process is performed to mount the LED packages  10  on the PCB  24  individually. As a result, it is almost impossible to produce the LED packages  10  in batch, and the manufacturing process of the electronic products is too complicated and tedious. As applied in a LED package  10  with high power, the cup-structure substrate  12  of the opto-electronic device  16  is unavoidably overheated, which may eventually result in a reduction of light intensity or failure of the entire device. Due to the significantly large volume of the single LED package  10  and the heat radiating demand required by a LED package  10  with high power, the designed size and the heat dissipating efficiency of the whole LED package  10  are greatly limited. 
       SUMMARY OF THE INVENTION 
       [0007]    It is the primary object of the present invention to provide an opto-electronic package structure having a Si-substrate. Accordingly, the present invention can improve the optical effect, the heat dissipating effect, and the reliability of the opto-electronic package structure, the opto-electronic package structure can be manufactured in batch, and the complexity of the opto-electronic package structure can be simplified. 
         [0008]    According to the claimed invention, an opto-electronic package structure having a Si-substrate is disclosed. The opto-electronic package structure includes a Si-substrate having a top surface, a plurality of connecters, and at least an opto-electronic device positioned on the top surface of the Si-substrate. The connecters are a layer covering the top surface of the Si-substrate, and the opto-electronic device is electrically connected to the connecters. 
         [0009]    Since the Si-substrates can be produced in a batch system utilizing micro-electromechanical processes or semiconductor processes, these Si-substrates are made with great precision and full of varieties. According to the characteristics of Si-substrate and the arrangement of the components, such as the connecters, the opto-electronic device, the cup-structure and the flip-chip bump on Si-substrate, the present invention can simplify the complexity of the components in the opto-electronic package structure, and increase the optical effect, the heat-dissipating effect and the packaging reliability of the opto-electronic package structure. 
         [0010]    These and other objectives of the present invention will no doubt become obvious to those of ordinary skill in the art after reading the following detailed description of the preferred embodiment that is illustrated in the various figures and drawings. 
     
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0011]      FIG. 1  is a schematic top view diagram showing a prior art surface mount device (SMD) LED package structure. 
           [0012]      FIG. 2  is a cross section diagram illustrating the prior art SMD LED package structure along  1 - 1 ′ line shown in  FIG. 1 . 
           [0013]      FIG. 3  is a schematic cross-sectional diagram illustrating an opto-electronic package structure having a Si-substrate according to a first preferred embodiment of the present invention. 
           [0014]      FIG. 4  is a schematic top view of the opto-electronic package structure shown in  FIG. 3 . 
           [0015]      FIG. 5  is a schematic diagram illustrating an opto-electronic package structure having a Si-substrate according to a second preferred embodiment of the present invention. 
           [0016]      FIG. 6  is a cross-sectional schematic diagram illustrating the opto-electronic package structure along line  5 - 5 ′ shown in  FIG. 5 . 
           [0017]      FIG. 7  is a cross-sectional schematic diagram illustrating an opto-electronic package structure having a Si-substrate according to a third preferred embodiment of the present invention. 
           [0018]      FIG. 8  is a cross-sectional schematic diagram illustrating an opto-electronic package structure having a Si-substrate according to a fourth preferred embodiment of the present invention. 
       
    
    
     DETAILED DESCRIPTION 
       [0019]    Please refer to  FIG. 3  and  FIG. 4 .  FIG. 3  is a schematic cross-sectional diagram illustrating an opto-electronic package structure  30  having a Si-substrate  32  according to a first preferred embodiment of the present invention, and  Fig.4  is a schematic top view of the opto-electronic package structure  30  shown in  FIG. 3 . It is to be understood that the drawings are not drawn to scale and are used only for illustration purposes. As shown in  FIG. 3  and  FIG. 4 , an opto-electronic package structure  30  includes a Si-substrate  32 , a plurality of connecters  34  and at least an opto-electronic device  36 . The material of the Si-substrate  32  includes polysilicon, amorphous silicon or single-crystal silicon. In addition, the Si-substrate  32  can be a rectangle silicon chip or a circular silicon chip, and can include integrated circuits or passive components therein. The Si-substrate  32  has a top surface and a bottom surface. A cup-structure  38  can be included on the top surface of the Si-substrate  32  for having a capacity of the opto-electronic device  36 . The Si-substrate  32  can control the optical effect of the opto-electronic package structure  30  by means of some factors, such as the position of the cup-structure  38 , the hollow depth of the cup-structure  38 , the hollow width of the cup-structure  38  and the sidewall shape of the cup-structure  38 . A plurality of electric-conducting holes  42  can be included in the Si-substrate  32 , and each electric-conducting hole  42  penetrates through the Si-substrate  32  from the top surface to the bottom surface. 
         [0020]    The connecters  34  include a plurality of substrate-penetrating electric-conducting wires  34   a  and at least a heat-conducting wire  34   b.  The substrate-penetrating electric-conducting wires  34   a  and the heat-conducting wire  34   b  can be formed in the meantime utilizing a micro-electromechanical process or a semiconductor process, such as a plating process or a deposition process. For forming the substrate-penetrating electric-conducting wires  34   a  and the heat-conducting wire  34   b,  a metal layer is formed on the top surface of the Si-substrate  32 , the bottom surface of the Si-substrate  32  and sidewalls of the electric-conducting holes  42  first. Thereafter, the substrate-penetrating electric-conducting wires  34   a  and the heat-conducting wire  34   b  are separated by means of an etching process so that the substrate-penetrating electric-conducting wires  34   a  and the heat-conducting wire  34   b  do not electrically connect to each other. Each substrate-penetrating electric-conducting wire  34   a  extends from the top surface of the Si-substrate  32  to the bottom surface of the Si-substrate  32  through at least one of the electric-conducting holes  42 . The heat-conducting wire  34   b  covers portions of the bottom surface of the Si-substrate  32 , and is preferably located in a position corresponding to the opto-electronic device  36 . Specifically speaking, the heat-conducting wire  34   b  can be a flat metal layer having large area, and each substrate-penetrating electric-conducting wire  34   a  can be a flat metal layer having large area or a metal circuit layer having circuit therein. 
         [0021]    The opto-electronic device  36  can be a light-emitting component or a photo sensor, such as a light emitting diode (LED), a photo diode, a digital micromirror device (DMD), or a liquid crystal on silicon (LCOS), but is not limited to those devices. The opto-electronic device  36  can be fixed onto the top surface of the Si-substrate  32  by a fixing gel. Furthermore, the positive electrode and negative electrode of the opto-electronic device  36  are then connected individually to the positive electrode terminal and the negative electrode terminal defined on the substrate-penetrating electric-conducting wires  34   a,  using a wire bonding technique or a flip-chip technique. 
         [0022]    In addition to above-mentioned components, the opto-electronic package structure  30  of the present invention can further include a packaging material layer  44 , an insulation layer  46 a and an optical film  46   b.  The packaging material layer  44  is composed of mixtures containing resin, wavelength converting materials, fluorescent powder, and/or light-diffusing materials. Next, the packaging material layer  44  is packaged onto the substrate  10  by a molding or sealant injection method so as to increase the product reliability of the opto-electronic package structure  30 , and to control the optical effect of the opto-electronic device  36 . The optical film  46   b  can be a coat having a high refractive index located on the bottom and the sidewall of the cup-structure  38 , and it can further increase the light quantity propagating from the opto-electronic package structure  30  in combination with the cup-structure  38 . 
         [0023]    Through the substrate-penetrating electric-conducting wires  34   a  on the bottom surface of the Si-substrate  32 , the opto-electronic package structure  30  can be connected onto a printed circuit board  48  by means of surface mounting. The printed circuit board  48  can be a glass fiber reinforced polymeric material, such as ANSI Grade. FR-1, FR-2, FR-3, FR-4 or FR-5, or a metal core printed circuit board. According to its concrete mounting process, a solder paste can first be formed on the surface of the printed circuit board  48  to be a metal connecting layer  52 . The metal connecting layer  52  corresponds to and connects with the substrate-penetrating electric-conducting wires  34   a  and the heat-conducting wire  34   b  positioned on the bottom surface of the opto-electronic package structure  30 . Therefore, the opto-electronic package structure  30  can electrically connect to the printed circuit board  48  through the substrate-penetrating electric-conducting wires  34   a  and the metal connecting layer  52 . On the other hand, in order to form a structure having different conducting paths for heat and for electrons, the produced heat of the opto-electronic device  36  can be transmitted to the surroundings through the heat conducting path constituted by the Si-substrate  32 , the heat-conducting wire  34   b,  the metal connecting layer  52  and the printed circuit board  48 . Once the metal connecting layer  52  is squeezed or the position of the metal connecting layer  52  deviates, the metal connecting layer  52  might contact with other components, and cause a short circuit. In order to prevent the metal connecting layer  52  from contacting with other components, the bottom surface of the Si-substrate  32  in the present invention can further include a plurality of trenches  54  to receive the unnecessary solder paste. Thus, the occurring probability of the short between the metal connecting layer  52  and other components can be easily reduced without using the expensive wafer having a high resistance. 
         [0024]    The opto-electronic package structure of the present invention can be arranged in other forms according to other embodiments. Please refer to  FIG. 5  and  FIG. 6 .  Fig.5  is a schematic diagram illustrating an opto-electronic package structure  60  having a Si-substrate  62  according to a second preferred embodiment of the present invention, and  Fig.6  is a cross-sectional schematic diagram illustrating the opto-electronic package structure  60  along line  5 - 5 ′ shown in  FIG. 5 , wherein like number numerals designate similar or the same parts, regions or elements. As shown in  FIG. 5  and  FIG. 6 , an opto-electronic package structure  60  includes a Si-substrate  62 , a plurality of connecters  34  and at least an opto-electronic device  36 . The material of the Si-substrate  62  includes polysilicon, amorphous silicon or single-crystal silicon, and can include integrated circuits or passive components therein. A cup-structure  38  is included in the top surface of the Si-substrate  62  so as to contain the opto-electronic device  36  therein. 
         [0025]    The connecters  34  include a plurality of substrate-penetrating electric-conducting wires  34   a  and can further include at least a heat-conducting wire  34   b.  In order to form the substrate-penetrating electric-conducting wires  34   a  and the heat-conducting wire  34   b  simultaneously, a metal layer is first formed on the top surface of the Si-substrate  62 , the bottom surface of the Si-substrate  62  and sidewalls of the electric-conducting holes  64  utilizing a plating process or a deposition process. Next, the substrate-penetrating electric-conducting wires  34   a  and the heat-conducting wire  34   b  are separated by means of an etching process so that the substrate-penetrating electric-conducting wires  34   a  and the heat-conducting wire  34   b  do not electrically connect to each other. Each substrate-penetrating electric-conducting wire  34   a  extends from the top surface of the Si-substrate  62  to the bottom surface of the Si-substrate  62  through at least one of the electric-conducting holes  64 . The heat-conducting wire  34   b  covers portions of the bottom surface of the Si-substrate  62 , and is preferably located in a position corresponding to the opto-electronic device  36 . In application, the heat-conducting wire  34   b  can be a flat metal layer having large area, and each substrate-penetrating electric-conducting wires  34   a  can be a flat metal layer having large area or a metal circuit layer having circuit therein. 
         [0026]    The positive electrode and negative electrode of the opto-electronic device  36  can first be connected individually to the positive electrode terminal and the negative electrode terminal defined on the substrate-penetrating electric-conducting wires  34   a  through a plurality of solder bumps  56 . Subsequently, the positive electrode and negative electrode of the opto-electronic device  36  are connected to a printed circuit board (not shown in the figure) through the substrate-penetrating electric-conducting wires  34   a  positioned on the bottom surface of the Si-substrate  62 . Additionally, in order to form a structure having different conducting paths for heat and for electrons, the opto-electronic device  36  can transmit the produced heat to the surroundings through the heat conducting path constituted by the Si-substrate  62 , the heat-conducting wire  34   b  and the printed circuit board. 
         [0027]    It should be noticed that the electric-conducting holes  42  of the first preferred embodiment penetrate parts of the Si-substrate  32  positioned under the cup-structure  38 , and the electric-conducting holes  64  of this embodiment penetrate parts of the Si-substrate  32  positioned around the cup-structures  38 . Because the electric-conducting holes  64  of this embodiment are located around the cup-structure  38 , the surface in the bottom and in the sidewall of the cup-structure  38  can be completely covered with the substrate-penetrating electric-conducting wires  34   a  of the connecters  34 . According to this arrangement, the substrate-penetrating electric-conducting wires  34   a  can promote light effect, electric effect and heat effect in the meantime. In addition to providing an electric conducting path, the metal of the substrate-penetrating electric-conducting wires  34   a  can also provide excellent reflecting effect, and increase an optical benefit. The substrate-penetrating electric-conducting wires  34   a  having metal material can even directly function as an optical film. Furthermore, the substrate-penetrating electric-conducting wires  34   a  formed by metal material has a great heat transfer coefficient, so the heat generated in the opto-electronic package structure  60  can be dissipated easily. 
         [0028]    Please refer to  FIG. 7  and  FIG. 8  showing other embodiments of the present invention.  FIG. 7  is a cross-sectional schematic diagram illustrating an opto-electronic package structure  70  having a Si-substrate  72  according to a third preferred embodiment of the present invention, and  FIG. 8  is a cross-sectional schematic diagram illustrating an opto-electronic package structure  80  having a Si-substrate  82  according to a fourth preferred embodiment of the present invention, wherein like number numerals designate similar or the same parts, regions or elements. 
         [0029]    As shown in  FIG. 7 , an opto-electronic package structure  70  includes a Si-substrate  72 , a plurality of connecters  34  and at least an opto-electronic device  36 . A cup-structure  38  is included in the top surface of the Si-substrate  72  so as to contain the opto-electronic device  36  therein. 
         [0030]    The connecters  34  can be a flat metal layer having large area or a metal circuit layer having circuits therein. The connecters  34  include a plurality of substrate-penetrating electric-conducting wires  34   a  for conducting electricity and at least a heat-conducting wire  34   b  for conducting heat. The positive electrode and negative electrode of the opto-electronic device  36  can first be connected individually to the positive electrode terminal and the negative electrode terminal defined on the substrate-penetrating electric-conducting wires  34   a  through a plurality of solder bumps  56 . Subsequently, the positive electrode and negative electrode of the opto-electronic device  36  are connected to a printed circuit board  48  through the substrate-penetrating electric-conducting wires  34   a.  It is worthy of note that the heat-conducting wire  34   b  positioned on the bottom surface of the opto-electronic package structure  70  can be further connected to at least a heat-dissipating device  74 , such as a fin. As a result, the opto-electronic device  36  can transfer the generated heat to the surrounding via the Si-substrate  72 , the heat-conducting wire  34   b  and the heat-dissipating device  74 , and form a structure having different conducting paths for heat and for electrons. 
         [0031]    As shown in  FIG. 8 , an opto-electronic package structure  80  includes a Si-substrate  82 , a plurality of connecters  34  and at least an opto-electronic device  36 . A cup-structure  38  is included in the top surface of the Si-substrate  82  so as to contain the opto-electronic device  36  therein. The connecters  34  can be a flat metal layer having large area or a metal circuit layer having circuit therein, and used for electrically connection, heat conduction and light benefit. The positive electrode and negative electrode of the opto-electronic device  36  can be connected individually to the positive electrode terminal and the negative electrode terminal defined on the connecters  34  through a plurality of solder bumps  56 , and then are connected to a printed circuit board  48  through the connecters  34 . Because the Si-substrate  82  can be produced by the micro-electromechanical processes or the semiconductor processes that are developed technology, the Si-substrate  82  can include a fin structure on the bottom surface of the opto-electronic package structure  80 . As a result, the opto-electronic device  36  can directly dissipate the generated heat through the Si-substrate  72 , and form a great heat-dissipating structure. 
         [0032]    After all components of the above-mentioned opto-electronic package structure are completed, the Si-substrates can be separated from each other by means of a wafer sawing process, and each opto-electronic package structure is electrically connected to the corresponding printed circuit board through the connecters of each Si-substrate. 
         [0033]    Because the present invention chooses the Si-substrate to form the opto-electronic package structure, and the heat transfer coefficient of silicon material is quite large, the heat-dissipating effect of the opto-electronic package structure can be increased. In addition, since silicon and an LED are both made from semiconductor materials, the coefficient of thermal expansion (CTE) of silicon is approximate to the CTE of the LED. Therefore, using silicon to form the packaging substrate can increase the reliability of the produced opto-electronic package structure. 
         [0034]    Furthermore, the opto-electronic package structure having the Si-substrate can be made in a batch system utilizing micro-electromechanical processes or semiconductor processes. According to this arrangement, the connecters can promote light effect, electric effect and heat effect in the meantime. In addition to providing electric conducting path, the metal characteristic of the connecters can also provide excellent reflecting effect, and increase an optical benefit. Even, the connecters having metal material can directly function as an optical film. Furthermore, the connecters formed by metal material has a great heat transfer coefficient, so the heat generated in the opto-electronic package structure can be dissipated easily. As a result, the present invention can simplify the complexity of the components in the opto-electronic package structure, and increase the optical effect, the heat-dissipating effect and the packaging reliability of the opto-electronic package structure. 
         [0035]    Those skilled in the art will readily observe that numerous modifications and alterations of the device and method may be made while retaining the teachings of the invention. Accordingly, the above disclosure should be construed as limited only by the metes and bounds of the appended claims.