Abstract:
The present invention relates to the apparatus and method for optical interconnection. The present invention provides an optical interconnection structure comprising: a substrate on which double side perforated multi-hole through a predetermined region is formed; bottom hole which is etched and tapered for optical fiber array is bigger than upper hole which is etched for the optical devices. The present invention provides the optical interconnection structure that can facilitate the optical interconnection between the active optoelectronic devices that transmit/receive the optical signals and the optical fiber array, making it possible to align easily and acutely between the optical devices and optical fiber array.

Description:
FIELD OF THE INVENTION  
       [0001]    The present invention relates to the apparatus and method for optical interconnection, and more particulraly, to an optical interconnection structure that double side perforated multi-hole through a predetermined region. 
       DESCRIPTION OF THE RELATED ART  
       [0002]    Optical active cable generally used to send optical signal such as DVI (Digital Visual Interface). Optical interconnection apparatus used to fix between the optical fiber array and optical device. 
         [0003]    This optical fiber apparatus is known for optical fiber connector. It connects optical fiber and optical device by the reticular shape body. For example, this optical interconnection apparatus is posted on 2008-46047 in Korea intellectual property office. 
         [0004]    Optical fiber connector has two entrances; one is for the optical devices and the other is for the optical fiber. Therefore, optical devices and optical fiber is aligned by inserting into the optical connector. 
         [0005]    Entrances for optical fiber holder and optical devices correspond to optical fiber and optical devices diameter. Therefore, optical devices and optical fiber holder are aligned by inserting into the optical connector. 
         [0006]    However, problems arise in that if optical connector has some misalignment, there is nothing to compensate between the optical devices and optical fiber. In other words, due to optical devices and optical fiber are aligned by inserting into the optical fiber connector, if optical connector has some misalignment; there is nothing to compensate. 
         [0007]    In addition, it is necessary additional optical connector to hold optical device and optical fiber. 
       SUMMARY OF THE INVENTION 
       [0008]    The present invention provides the optical interconnection structure that can facilitate the optical interconnection between the active optoelectronic devices that transmit/receive the optical signals and the optical fiber array, making it possible to align easily and acutely between the optical devices and optical fiber array. 
         [0009]    In order to solve the above problems, it is an object of the present invention to provide an optical interconnection structure that aligns between the optical devices and optical fiber array on the same axis easily by using perforated hole. Tapered hole make it possible to delicate control to the optical fiber array in an inserted state. Therefore, it can accurately align between the optical fiber core and optical devices. 
         [0010]    It is another object of the present invention to provide an optical interconnection structure that can be manufactured in great quantities and remarkably improved in view of yield by allowing the semiconductor process at a wafer level to be performed during the processes for forming double side perforated hole on the substrate. 
         [0011]    In order to accomplish the objects, according to a first aspect of the present invention, there is provided an optical interconnection structure comprising: a substrate on which double side perforated multi-hole through a predetermined region is formed, the perforated multi-hole includes bottom hole which is etched and tapered for optical fiber array, in that the inner surface thereof is tilted and the entrance thereof is bigger than bottom surface, to make delicate control to the optical fiber array in an inserted state; and upper hole which is etched for the optical devices which are bonded on the substrate. 
         [0012]    Preferably, the end point of the optical fiber array is located in n the boundary between bottom surface and the inner surface. 
         [0013]    The substrate may be formed by a epoxy PCB, metal PCB, silicon PCB and glass PCB (printed circuit board) material and etched by deep trench RIE (reactive ion etcher system), electro chemical drill or femto-second laser process. 
         [0014]    The optical interconnection structure preferably includes an optical fiber array; epoxy filled between the inner surface of the bottom hole and the optical fiber array  30 ; an optical device which is located to be aligned with the optical fiber array through the upper hole. 
         [0015]    According to a second aspect of the present invention, there is provided a method for optical interconnection comprising: (a) forming the perforated multi-hole on double side of substrate in a predetermined region, the perforated multi-hole including bottom hole which is etched and tapered for optical fiber array, in that the inner surface thereof is tilted and the entrance thereof is bigger than bottom surface; (b) attaching an optical device on the substrate by flip chip bonding; (c) aligning an optical fiber array to the optical device through the perforated hole; (d) filling epoxy between the bottom hole and optical fiber array; and (e) exposing UV light. 
         [0016]    Preferably, the substrate includes the electrical line pattern and the optical device is bonding by flip chip. 
         [0017]    According to the present invention, there is provided an optical interconnection structure including: a substrate is made by metal, silicon and glass PCB (printed circuit board). Optical fiber array is aligned on the same axis by the perforated hole. Tapered hole can lead the optical fiber array to easily align. Optical devices such as laser diode and photodiode are attached by flip chip bonding on the substrate. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0018]      FIG. 1  explains an optical interconnection structure according to an embodiment of the present invention; and 
           [0019]      FIG. 2  is a cross-sectional view explaining an optical interconnection structure according to an embodiment of the present invention. 
           [0020]      FIG. 3  explains a method for manufacturing an optical interconnection structure according to an embodiment of the present invention. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0021]    Hereinafter, the embodiments of the present invention will be described in detail with reference to the accompanying drawings. However, the embodiments of the present invention may be modified in various shapes and the scope of the present invention is not limited to the embodiments set forth below. The embodiments of the present invention are provided for more completely explaining the present invention to those skilled in the art. 
         [0022]      FIG. 1  explains an optical interconnection structure according to an embodiment of the present invention.  FIG. 2  is a cross-sectional view explaining an optical interconnection structure according to an embodiment of the present invention. 
         [0023]    The optical interconnection structure of  FIG. 1  includes bottom hole  22  of optical fiber insertion, upper hole  28  of optical path and a substrate  10  on which multi-hole  20  perforating through a predetermined region is formed. Each optical fiber array  30  and each optical device  40  can be aligned through the perforated hole  20  of a substrate  10 . 
         [0024]    The substrate  10  preferably is formed by a metal, silicon or glass PCB (printed circuit board) material. According to the present invention, optical interconnection structure is formed by optical interconnection substrate  10  such as PCB. Therefore, optical devices  40  such as laser diode or photo diode can be packaged on the PCB substrate which is electrical patterned. Therefore, optical devices  40  can be easily connected with the optical interconnection structure which has electrical pattern. Therefore, additional process is not needed to connect with the optical interconnection structure. 
         [0025]    A substrate  10  on which double side perforated multi-hole  20  through a predetermined region is formed. Each perforated multi-hole  20  include bottom hole  22  of optical fiber and upper hole  28  of optical path. 
         [0026]    Bottom hole  22  is etched to allow the optical fiber to insert on the PCB substrate  10 . Bottom hole  22  is etched about 200˜300 um by deep trench RIE (reactive ion etcher system), electro chemical drill or femto-second laser process. The bottom hole  22  has a tapered shape with cone shape. In the bottom hole  22 , the inner surface  25  thereof is tilted and the entrance thereof is bigger than bottom surface  24 . The inner surface  25  can lead the optical fiber array  30  to easily align. Due to the bottom hole  22  which is tapered for optical fiber array is bigger than the upper hole  28 , it is possible to make delicate control to the optical fiber array  30  in an inserted state. Therefore, controlling the optical fiber array  30 , it can accurately align between the optical fiber core  35  and optical devices  40 . In the boundary between bottom surface  24  and the inner surface  25 , the end point of the optical fiber array  30  is located. The entrance  23  of the bottom hole  22  is bigger than bottom surface  24 . The bottom surface  24  and the inner surface  25  have taper shapes which is similar to cone shape. This is why it can accurately align between the optical fiber core  35  and optical devices  40 . 
         [0027]    There are about 20˜100 um gap (g) between the entrance  23  of the bottom hole  22  and optical fiber array  30 . 
         [0028]    To cope with the optical fiber core, the upper hole  28  size is smaller than the bottom hole  22  size. 
         [0029]    Upper hole  28  provides the optical path which light pass though the optical fiber core and etched height is about 150 um. 
         [0030]    Perforated hole  20  on the PCB substrate  10  is fabricated by etching process. In the case of wiring pattern is designed on the PCB substrate  10 , wiring pattern and perforated hole  20  can be formed by etching process. Therefore, perforated hole  20  can be made without additional micro fabrication. 
         [0031]    The embodiments of the present invention includes optical fiber array  30  which is connected with perforated hole  20  on the substrate  10  and optical devices  40 . 
         [0032]    Optical fiber array  30  is aligned on the same axis by the perforated hole  20 . The inner surface  25  can lead the optical fiber array  30  to easily align. Due to the bottom hole  22  which is tapered for optical fiber array is bigger than the upper hole  28 , it is possible to make delicate control to the optical fiber array  30  in an inserted state. Therefore, controlling the optical fiber array  30 , it can accurately align between the optical fiber core and optical devices. 
         [0033]    Optical devices  40  are packaged on the PCB substrate  10 . There are several methods to bond between optical devices  40  and the substrate  10  such as flip chip bonding or wire boding. However, in the case of micro-lens  42  integrated optical devices  40  such as laser diode and photodiode, flip chip bonding is more preferred. The flip chip bonding height  45  is about 20 um. Microlens is aligned by the optical path hole  28 . 
         [0034]    Optical fiber array  30  is fixed by inserting it into the bottom hole  22 . The inner surface  25  can lead the optical fiber array  30  to easily align. Due to the bottom hole  22  which is tapered for optical fiber array is bigger than the upper hole  28 , it is possible to make delicate control to the optical fiber array  30  in an inserted state. Therefore, controlling the optical fiber array  30 , it can accurately align between the optical fiber core  35  and optical devices  40 . 
         [0035]    Epoxy  50  is filled between the inner surface  25  and optical fiber array  30  and then UV light is exposed to cure. Therefore, optical fiber array  30  is fixed on the substrate  10 . 
         [0036]      FIG. 3  explains a method for manufacturing an optical interconnection structure according to an embodiment of the present invention. The substrate  10  preferably is formed by a metal, silicon or glass PCB (printed circuit board) material. 
         [0037]    A substrate  10  on which double side perforated multi-hole through a predetermined region is formed (S 10 ). 
         [0038]    Perforated hole  20  consists of bottom hole  22  for optical fiber array insertion and upper hole  28  for optical path. Perforated hole  20  is formed by etching process, and the bottom hole  22  is tapered. 
         [0039]    Etching process S 10  includes the optical interconnection surface  12 , if necessary, wiring pattern can be formed other surface. These kinds of wiring pattern can be used for electrical connection between optical devices  40  or between optical interconnection substrate  10 . 
         [0040]    Alignment step S 20 , optical fiber array  30  is aligned on the same axis by inserting into the perforated hole. Epoxy  50  is filled S 30  between the inner surface  25  and optical fiber array  30  and UV light is exposed S 40  to cure. 
         [0041]    Epoxy  50  can be substituted of other materials which have the similar characteristics. These kinds of materials are treated the same as epoxy. 
         [0042]    The embodiments of the present invention include optical devices  40  attachment S 15  on the substrate  10 . Before or after the optical fiber array insertion, optical devices attachment can be done. Desirable, optical devices are attached before the optical fiber array insertion.