Abstract:
Disclosed herein is a structure of opto-electronic package having Si-substrate. The Si-substrates are manufactured in batch utilizing the micro-electromechanical processes or the semiconductor processes, so that these Si-substrates are made with great precision and full of varieties. Base 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 opto-electronic package structure, and simplifies the complexity of the opto-electronic package structure.

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, a Si-substrate having flip-chip bumps is disclosed. The Si-substrate has a top surface and a bottom surface. In addition, the Si-substrate includes a plurality of electric-conducting holes, a plurality of connecters, and a plurality of flip-chip bumps positioned on the top surface of the Si-substrate. Each of the electric-conducting holes penetrates through the Si-substrate from the top surface to the bottom surface. The connecters include a plurality of substrate-penetrating electric-conducting wires and at least a heat-conducting wire. Each of the substrate-penetrating electric-conducting wires extends from the top surface of the Si-substrate to the bottom surface of the Si-substrate through the electric-conducting holes, and the heat-conducting wire covers portions of the bottom surface of the Si-substrate. The flip-chip bumps are electrically connected to the substrate-penetrating electric-conducting wires. 
         [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 cross-sectional schematic diagram illustrating a Si-substrate having flip-chip bumps according to a first preferred embodiment of the present invention. 
           [0014]      FIG. 4  is a schematic diagram illustrating an opto-electronic package structure having a Si-substrate according to a second preferred embodiment of the present invention. 
           [0015]      FIG. 5  is a cross-sectional schematic diagram illustrating the opto-electronic package structure along line  5 - 5 ′ shown in  FIG. 4 . 
           [0016]      FIG. 6  is a cross-sectional schematic diagram illustrating opto-electronic package structures having Si-substrates according to a third preferred embodiment of the present invention. 
       
    
    
     DETAILED DESCRIPTION 
       [0017]    Please refer to  FIG. 3 .  FIG. 3  is a cross-sectional schematic diagram illustrating a Si-substrate having flip-chip bumps according to a first preferred embodiment of the present invention. It is to be understood that the drawings are not drawn to scale and are served only for illustration purposes. As shown in  FIG. 3 , a Si-substrate  92  includes a plurality of connecters  94  and a plurality of flip-chip bumps  96 . The Si-substrate  92  itself has a plurality of electric-conducting holes  98 , and each electric-conducting hole  98  penetrates the Si-substrate  92  from the top surface to the bottom surface. The connecters  94  include a plurality of substrate-penetrating electric-conducting wires  94   a  and at least a heat-conducting wire  94   b , and each substrate-penetrating electric-conducting wire  94  extends from the top surface of the Si-substrate  92  to the bottom surface of the Si-substrate  92  through the electric-conducting holes  98 . The heat-conducting wire  94   b  covers parts of the bottom surface of the Si-substrate  92 , and is preferably formed on the position of the Si-substrate  92 , where the heat should be transfer outward. It should be noticed that the flip-chip bumps  96  are formed directly on the top surface of the Si-substrate  92 , and electrically connected to the substrate-penetrating electric-conducting wires  94   a.    
         [0018]    Because the present invention can produce the Si-substrate by means of the micro-electromechanical process or the semiconductor process, bumps can be directly formed on the surface of the Si-substrate, and thereafter connect to the follow-up opto-electronic device. In light of this structure, a plurality of the Si-substrates  92  having flip-chip bumps  96  in this embodiment can be produced in one wafer simultaneously. After all components of the above-mentioned Si-substrates  92  are completed, the Si-substrates  92  can be separated from each other by means of a wafer sawing process, and each Si-substrates  92  can be electrically connected to a corresponding opto-electronic device directly through the flip-chip bumps  96  of each Si-substrate  92 . Therefore, the present invention benefits from low cost and consistency with standard micro-electromechanical processes and semiconductor processes. Furthermore, the present invention has no need to form the flip-chip bumps  96  on the Si-substrates  92  one by one during the packaging processes, so it significantly increases the production of packaging. 
         [0019]    Please refer to  FIG. 4  and  FIG. 5 .  FIG. 4  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. 5  is a cross-sectional schematic diagram illustrating the opto-electronic package structure  60  along line  5 - 5 ′ shown in  FIG. 4 , wherein like number numerals designate similar or the same parts, regions or elements. As shown in  FIG. 3  and  FIG. 4 , an opto-electronic package structure  60  includes a Si-substrate  62 , a plurality of connecters  34  and a plurality of solder bumps  56 . The material of the Si-substrate  62  includes polysilicon, amorphous silicon or single-crystal silicon. In addition, the Si-substrate  62  can be a rectangle silicon chip or a circular silicon chip, and can include integrated circuits or passive components therein. The Si-substrate  62  has a top surface and a bottom surface. A cup-structure  38  is included in the top surface of the Si-substrate  62  so as to contain an opto-electronic device  36  therein. A plurality of electric-conducting holes  64  can be included in the Si-substrate  62 , and each electric-conducting hole  64  penetrates through the Si-substrate  62  from the top surface to the bottom surface. 
         [0020]    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 . 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. 
         [0021]    After all components of the Si-substrate  62  are completed, the Si-substrate  62  can be diced from a wafer, and each Si-substrate  62  can be electrically connected to the corresponding opto-electronic device  36  directly through the flip-chip bumps  56  of the Si-substrate  62 . 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  62  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 flip-chip technique. 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 . 
         [0022]    In addition to above-mentioned components, the opto-electronic package structure  60  of the present invention can further include a packaging material layer (not shown in the figure), an insulation layer (not shown in the figure) and an optical film (not shown in the figure). The packaging material layer is composed of mixtures containing resin, wavelength converting materials, fluorescent powder, and/or light-diffusing materials. The packaging material layer is packaged onto the Si-substrate  62  by a molding or sealant injection method so as to increase the product reliability of the opto-electronic package structure  60 , and to control the optical effect of the opto-electronic device  36 . The optical film 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  60  in combination with the cup-structure  38 . 
         [0023]    In other preferred embodiments of the present invention, the Si-substrates can be diced from a wafer after the packaging material layer is packaged onto the Si-substrate by a molding or sealant injection method to package the opto-electronic package structure. Please refer to  FIG. 6 .  FIG. 6  is a cross-sectional schematic diagram illustrating opto-electronic package structures  150  having Si-substrates  152  according to a third preferred embodiment of the present invention. As shown in  FIG. 6 , a plurality of opto-electronic package structures  150  are defined in a silicon wafer  151 , and each opto-electronic package structure  150  includes a Si-substrate  152 . Each of the Si-substrates  152  includes a plurality of connecters  154 , a plurality of solder bumps  56  electrically connected to the connecters  154 , and at least an opto-electronic device  156  electrically connected to the corresponding solder bumps  56 . Accordingly, at least one of the Si-substrates  152  includes electric-conducting holes  312 , and each connector  154  on this Si-substrates  152  extends from the top surface of the Si-substrate  152  to the bottom surface of the Si-substrate  152  through at least one of the electric-conducting holes  312 . On other hand, at least one of the opto-electronic devices  156  is located on the top surface of an un-hollow Si-substrates  152 . The bottom surface of the un-hollow Si-substrate  152  can be a fin structure so as to increase the heat-dissipating efficiency. 
         [0024]    After all components of the opto-electronic package structures  150  are completed, the Si-substrates  152  can be separated from each other by means of a wafer sawing process, and each opto-electronic package structure  150  is electrically connected to the corresponding printed circuit board through the connecters of each Si-substrate  152 . 
         [0025]    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 approximately equal 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. 
         [0026]    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 the characteristics of the 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. 
         [0027]    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.