Patent Publication Number: US-2009226139-A1

Title: Optoelectronic component and optical subassembly for optical communication

Description:
BACKGROUND OF THE INVENTION 
     1. Field of Invention 
     The invention relates to a component for optical communication, and more particularly to an optical sub-assembly composed of a barrel and an optoelectronic component, wherein the package types of the optoelectronic component include TO-can (TO Open Can) architecture and leadframe architecture, and the type of the barrel may be SC, ST, LC, or their individual pigtail architecture. 
     2. Related Art 
     The optical communication is to achieve the signal transmission effect via optical-to-electrical conversion. An optical sub-assembly (OSA) to be connected to an optical fiber connector has to be located at each of a signal transmitting end and a signal receiving end. 
     U.S. Pat. No. 7,290,946 discloses an optical sub-assembly, which is composed of an optoelectronic component and a barrel combined together, in one of the examples thereof. A housing of the optoelectronic component is formed with an opening so that the effect of the high alignment yield can be achieved. Also, the &#39;946 patent discloses that a glue is coated on or filled inside the optoelectronic component so that the optoelectronic die is isolated from air, or the glue is filled into the space between the optoelectronic die and the optical coupling structure so as to protect the optoelectronic die. 
     U.S. Pat. Nos. 6,588,949 and 6,283,644 also disclose that a glue is formed into a thick film to cover the optoelectronic die and achieve the effect of protecting the optoelectronic die. However, it is very difficult to prevent the formation of the thick film from having the thickness of several tens of micrometers, at least in general, if the frequently-used conventional glue (e.g., epoxy or silicone) is adopted. As a result, the shape and thickness of the thick film do not have the consistency due to the formation of bubbles and/or surface tension regarding the glue. Thus, the optical properties of the products cannot be well controlled. 
     SUMMARY OF THE INVENTION 
     A housing of an optoelectronic component of the invention, especially a TO-can/leadframe housing, has an opening, and no glass or lens is located on the housing, so the manufacturing cost can be lowered. In addition, an optical coupling structure may penetrate through the opening so as to approach an optoelectronic device/optoelectronic die of the optoelectronic component. The housing of the optoelectronic component may be made by metal, plastic or resin, and the housing has an opening. 
     Glue or index matching oil is filled into the optoelectronic component of the invention, so the light can be converged with a low diverging angle as travelling through the glue or the index matching oil. In addition, the glue or the index matching oil can protect and/or fix the optoelectronic device or the optoelectronic die. Also, it is also possible to coat a thin film material (e.g., a fluoro-polymer of a polymeric, high volatile dilute material) with a low viscosity coefficient on the surface of the optoelectronic device/optoelectronic die and/or the matching component, e.g., integrated circuit (IC) and active/passive device, without using the above mentioned materials. Thus, it is expected to form a surface protection film against damp heat (high temperature and high humidity) and to reduce the influence of the optical and/or electrical properties. More particularly, regarding to the optoelectronic die with the thin film material coated and located in the housing with/without the opening or directly in a barrel, no matter in which is eventually hermetically sealed or non-hermetically sealed, the property thereof can be improved or the quality thereof can be stabilized. 
     The optoelectronic die of the invention may be located on an integrated circuit, and the combination of the optoelectronic die and the integrated circuit may be located on a submount. Thus, the area occupied by each assembly can be reduced so that the spatial availability can be optimized. In addition, the size of the optoelectronic component can be reduced and the high-frequency performance can be enhanced. Furthermore, the submount can also be removed so that the spatial availability can be further improved and the size of the optoelectronic component can be much more reduced. 
     In the optoelectronic component of the invention, it is assumed that its housing has an opening and is used in conjunction with the optoelectronic device without the submount, and then the thin film material with a low viscosity coefficient covers the optoelectronic die and/or the matching component, and finally combined with the barrel. In this case, the optoelectronic die or the matching component may have the improved or stabilized quality due to the protection of the low-viscosity material regardless of whether the chamber of the optoelectronic component is hermetically sealed with the barrel. The opening thereof may further let the lens on the first surface of the barrel go inside to approach the optoelectronic die so that the submount may be omitted, the cost or the product size can be further reduced. 
     Further scope of the applicability of the present invention will become apparent from the detailed description given hereinafter. However, it should be understood that the detailed description and specific examples, while indicating preferred embodiments of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The present invention will become more fully understood from the detailed description given hereinbelow and the accompanying drawings which are given by way of illustration only, and thus are not limitative in the present invention. 
         FIG. 1   a  is a schematic illustration showing a structure of an optoelectronic component with the TO-can architecture with the opening according to the invention. 
         FIG. 1   b  is a schematic illustration showing the optoelectronic component with the TO-can architecture but without the housing according to the invention. 
         FIG. 2  is a schematic illustration showing the optoelectronic component with the leadframe architecture according to the invention. 
         FIG. 3  is a schematic illustration showing another optoelectronic component with another leadframe architecture according to the invention. 
         FIG. 4   a  is a schematic illustration showing a structure, in which an optoelectronic die of the optoelectronic device of the invention is located on a submount. 
         FIG. 4   b  is a schematic illustration showing another structure, in which the optoelectronic die of the optoelectronic device of the invention is located on the submount. 
         FIG. 5   a  is a schematic illustration showing a structure, in which the film of the invention covers the surface of the optoelectronic device. 
         FIG. 5   b  is another schematic illustration showing another structure, in which the film of the invention covers the surface of the optoelectronic device. 
         FIG. 6   a  is a schematic illustration showing a structure, in which an optoelectronic die of the optoelectronic device of the invention is located on a matching component. 
         FIG. 6   b  is another schematic illustration showing another structure, in which the optoelectronic die of the optoelectronic device of the invention is located on the matching component and includes a submount. 
         FIG. 7   a  is a schematic illustration showing a structure, in which the film of the invention covers the surface of the optoelectronic device. 
         FIG. 7   b  is another structure schematic illustration showing another structure, in which the film of the invention covers the surface of the optoelectronic device and includes a submount. 
         FIG. 8   a  is a schematic illustration showing the structure of the optoelectronic component of the invention without a housing, wherein the optoelectronic die is located on the matching component. 
         FIG. 8   b  is a schematic illustration showing the structure of the optoelectronic component of the invention with the housing, wherein the optoelectronic die is located on the matching component. 
         FIG. 8   c  is a schematic illustration showing the structure of the optoelectronic component of the invention, wherein a spherical lens is located on the housing and the optoelectronic die is located on the matching component. 
         FIG. 8   d  is a schematic illustration showing the structure of the optoelectronic component of the invention, wherein a piece of flat window is located on the housing and the optoelectronic die is located on the matching component. 
         FIG. 8   e  is a schematic illustration showing the structure of the optoelectronic component of the invention, wherein a lens structure is located on the housing and the optoelectronic die is located on the matching component. 
         FIG. 9   a  is a schematic illustration showing the structure of the optoelectronic component of the leadframe architecture of the invention without a housing, wherein the optoelectronic die is located on the matching component. 
         FIG. 9   b  is a schematic illustration showing the structure of the optoelectronic component of the leadframe architecture of the invention with the housing, wherein the optoelectronic die is located on the matching component. 
         FIG. 9   c  is a schematic illustration showing the structure of the optoelectronic component of the leadframe architecture of the invention with a housing of a covering structure, wherein the optoelectronic die is located on the matching component. 
         FIG. 9   d  is a schematic illustration showing the structure of the optoelectronic component of the leadframe architecture of the invention, wherein the housing is formed with a lens structure and the optoelectronic die is located on the matching component. 
         FIG. 10   a  is a schematic illustration showing that the same side of the optoelectronic die of the invention has two electrodes combined with the matching component. 
         FIG. 10   b  is a schematic illustration showing that the same side of the optoelectronic die of the invention has two electrodes combined with the matching component. 
         FIG. 10   c  is a schematic illustration showing that the optoelectronic die of the invention is combined with the matching component by the flip chip technique. 
         FIG. 10   d  is a schematic illustration showing that the optoelectronic die of the invention is combined with the matching component by the flip chip technique. 
         FIG. 10   e  is a schematic illustration showing that the opposite sides of the optoelectronic die of the invention have electrodes combined with the matching component. 
         FIG. 10   f  is a schematic illustration showing that the opposite sides of the optoelectronic die of the invention have electrodes combined with the matching component. 
         FIG. 10   g  is a schematic illustration showing the electrical connection structure formed by a branch capacitor of the invention and the optoelectronic die. 
         FIG. 11   a  is a schematic illustration showing a structure, in which the optoelectronic die of the invention is located on the header. 
         FIG. 11   b  is a schematic illustration showing a structure, in which the optoelectronic die of the invention is located on the header, and the film covers the surface of the optoelectronic die. 
         FIG. 11   c  is a schematic illustration showing a P-side down assembly of the optoelectronic component of the invention. 
         FIG. 12  is a schematic illustration showing a P-side up assembly of the optoelectronic component of the invention. 
         FIG. 13   a  is a schematically assembled view showing a P-side up assembly of the optoelectronic component of the invention, wherein a transimpedance amplifier is provided. 
         FIG. 13   b  is a schematically assembled view showing a branch capacitor located in the optoelectronic component of the invention. 
         FIG. 13   c  is a schematically assembled view showing the optoelectronic component of the invention, in which a chip-type transimpedance amplifier and a postamplifier are provided. 
         FIG. 14   a  is a schematically assembled view showing the optoelectronic component of the invention, in which a chip-type driver IC is provided. 
         FIG. 14   b  is a schematically assembled view showing that two optoelectronic dies and a chip-type driver IC are located on the header of the invention. 
         FIG. 15   a  is a schematic illustration showing a structure of the optoelectronic component of the invention without a housing, wherein the optoelectronic die is located on the header. 
         FIG. 15   b  is a schematic illustration showing a structure of the optoelectronic component of the invention with a housing, wherein the optoelectronic die is located on the header. 
         FIG. 15   c  is a schematic illustration showing a structure of the optoelectronic component of the invention, wherein a spherical lens is located on the housing and the optoelectronic die is located on the header. 
         FIG. 15   d  is a schematic illustration showing a structure of the optoelectronic component of the invention, wherein a piece of flat window is located on the housing and an optoelectronic die is located on the header. 
         FIG. 15   e  is a schematic illustration showing a structure of the optoelectronic component of the invention, wherein a lens structure is located on the housing and the optoelectronic die is located on the header. 
         FIG. 16   a  is a schematic illustration showing a structure of the optoelectronic component of the leadframe architecture of the invention without a housing, wherein the optoelectronic die is located on the header. 
         FIG. 16   b  is a schematic illustration showing a structure of the optoelectronic component of the leadframe architecture of the invention with a housing and an opening, wherein the optoelectronic die is located on the header. 
         FIG. 16   c  is a schematic illustration showing a structure of the optoelectronic component of the leadframe architecture of the invention with the housing of the covering structure, wherein the optoelectronic die is located on the header. 
         FIG. 16   d  is a schematic illustration showing a structure of the optoelectronic component of the leadframe architecture of the invention, wherein the housing is formed with a lens structure and the optoelectronic die is located on the header. 
         FIG. 17   a  is a schematic illustration showing another structure showing another optoelectronic component with another leadframe of the invention without a housing. 
         FIG. 17   b  is a schematic illustration showing another structure showing another optoelectronic component with another leadframe of the invention with the housing. 
         FIGS. 18   a  to  18   d  are schematic illustrations showing four structures of barrels of the invention, which are frequently seen. 
         FIG. 19   a  is a schematic illustration showing a structure, in which the lens of the optical sub-assembly of the invention extends to approach the optoelectronic device. 
         FIG. 19   b  is a schematic illustration showing a structure, in which the lens of the optical sub-assembly of the invention extends to approach the optoelectronic device, wherein the film covers the surface of the optoelectronic device. 
         FIG. 19   c  is a schematic illustration showing a structure, in which the lens of the optical sub-assembly of the invention extends to approach the optoelectronic device, wherein the film covers the surface of the optoelectronic device and the optoelectronic die is fixed on the header; 
         FIG. 20   a  is a schematic illustration showing a structure, in which a index matching oil is filled, according to the invention. 
         FIG. 20   b  is a schematic illustration showing another structure, in which the index matching oil is filled, according to the invention. 
         FIG. 20   c  is a schematic illustration showing a structure, in which a glue is filled, according to the invention. 
         FIG. 20   d  is a schematic illustration showing another structure, in which the glue is filled, according to the invention. 
         FIG. 20   e  is a schematic illustration showing still another structure, in which the glue is filled, according to the invention. 
         FIG. 20   f  is a schematic illustration showing yet still another structure, in which the glue is filled, according to the invention. 
         FIG. 20   g  is a schematic illustration showing a structure, in which the optoelectronic device coated with the glue, according to the invention. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     The present invention will be apparent from the following detailed description, which proceeds with reference to the accompanying drawings, wherein the same references relate to the same elements. 
       FIG. 1   a  shows an optoelectronic component  10  with the TO-can architecture. Referring to  FIG. 1   a , the optoelectronic component  10  has a metal header  12  and a metal housing  14 , both can be combined into a single unit. A housing chamber  15  is formed inside the housing  14 . An optoelectronic device  16  is mounted in the housing  14  and fixed to the header  12 . 
     More particularly, one end of the housing  14  has an opening  18 . The opening  18  is communicated with the housing chamber  15  and located opposite the optoelectronic device  16 . 
       FIG. 1   b  shows an optoelectronic component  10   a , in which no housing is disposed on the header  12 , so the optoelectronic device  16  has an open periphery. In other words, the optoelectronic device  16  emits or receives light, which is similar to that of  FIG. 1   a.    
       FIG. 2  shows an optoelectronic component  20  with a leadframe architecture. The optoelectronic component  20  has a plurality of metal leads (only two metal leads  21   a  and  21   b  are depicted in  FIG. 2 ), and one end of the frame  21   a  serves as a header  22 . A resin housing  24  is combined with one end of each of the metal frames  21   a  and  21   b . An optoelectronic device  26  is located in the housing  24  and fixed to the header  22 . 
     More particularly, an opening  28  is formed at one end of the housing  24  and located opposite the optoelectronic device  26 . Because the depth direction of the opening  28  directs to the optoelectronic device  26 , a housing chamber  25  is formed inside the resin housing  24 . 
       FIG. 3  shows another optoelectronic component  30  with a leadframe architecture. Unlike the previous embodiment, a header  32  is made of a plastic, resin or metal material and combined with one end of each of metal leads  31   a  and  31   b . An optoelectronic device  36  is located on the header  32 . 
     In addition, a plastic or resin housing  34  is combined with the header  32 . An opening  38  is formed at one end of the housing  34 , and a housing chamber  35  communicating with the opening  38  is formed inside the housing  34 . During packaging, the optoelectronic device  36  is located inside the housing  34  and fixed to the header  32 , and opposite the opening  38 . 
     The housings  14 ,  24  and  34  of the optoelectronic components  10 ,  20  and  30  according to the embodiments respectively have openings  18 ,  28  and  38  located opposite the optoelectronic devices  16 ,  26  and  36 . 
     Each of the optoelectronic devices  16 ,  26  and  36  may sometimes include a submount, at least one optoelectronic die and with at least one or without any matching component. 
     Taking the optoelectronic device  16  as an example, the arrangement of each assembly includes various types as follows. The arrangements for other optoelectronic devices  26  and  36  may be obtained analogically. 
     First Type: Optoelectronic Die is Located on Submount 
       FIG. 4   a  shows a submount  42  of the optoelectronic device  16  mounted on the header  12 . An optoelectronic die  44  is fixed to the submount  42 , and a matching component  46  is mounted on the header  12 .  FIG. 4   b  shows that the optoelectronic die  44  and the matching component  46  are mounted on the submount  42 , and that the submount  42  is disposed on the header  12 . 
       FIGS. 5   a  and  5   b  shows an extended structure, which further has a thin film  48  covering the surface of the optoelectronic device  16 , or the surfaces of the optoelectronic die  44  and the matching component  46 , or the surfaces of the optoelectronic die  44 , the matching component  46  and the submount  42 . The thin film  48  may also only cover the surface or a portion of the surface of the optoelectronic die and/or the matching component. More particularly, the thin film  48  is covered on an active region of the optoelectronic die  44 . 
     Second Type: Optoelectronic Die is Located on Matching Component 
       FIG. 6   a  shows that the optoelectronic device  16  is an optoelectronic die  44  stacked on a matching component  46 , and the combination thereof is disposed on the header  12 . In the architecture, the matching component  46  may be served as a lower fixing component for the optoelectronic die  44 , and may adjust the position (height) of the optoelectronic die  44 .  FIG. 6   b  shows that the combination of the optoelectronic die  44  and the matching component  46  is located on a submount  42 , which is located on the header  12 . Consequently, the submount  42  and the matching component  46  may cooperate with each other to so that the position (height) of the optoelectronic die  44  can be adjusted. 
       FIGS. 7   a  and  7   b  show the extended structure, which further has a film  48  covering the partial or whole surface of the optoelectronic device  16 . For example, the film  48  only covers the surface of the optoelectronic die  44 . 
     Taking the optoelectronic device with the TO-CAN architecture but without the film as an example, the assembled architecture of the optoelectronic device and the housing will be described in the following. 
       FIG. 8   a  shows that no housing is located around the header  12 . So, an open space is formed around of the optoelectronic die  44  and the matching component  46 . 
       FIG. 8   b  shows that a metal housing  14  is located on the header  12 , wherein an opening  18  is particularly formed at one end of the housing  14  and located opposite the optoelectronic die  44 . The combination of the optoelectronic die  44  and the matching component  46  is located on the header  12 . 
       FIG. 8   c  shows that a metal housing  14  is located on the header  12 , wherein a spherical lens  50  is particularly located at one end of the housing  14  and opposite the optoelectronic die  44 . 
       FIG. 8   d  shows that a metal housing  14  is located on the header  12 , wherein a piece of flat window  51  is particularly located at one end of the housing  14  and opposite the optoelectronic die  44 . 
       FIG. 8   e  shows that a metal housing  14  is located on the header  12 , wherein a lens structure  52  is particularly located at one end of the housing  14  and opposite the optoelectronic die  44 . The lens can be an aspherical lens or any kind of light-converging device. 
     The header  12  is a metal header. In addition, the optoelectronic device  16  with the thin film  48  may be used in each embodiment of the invention. 
     Taking the optoelectronic device with the leadframe architecture but without the film as an example, the combined architecture of the optoelectronic device and the housing will be described in the following. 
       FIG. 9   a  shows that an optoelectronic component  26  has a plurality of metal leads (only two metal leads  21   a  and  21   b  are depicted in the drawing). An end portion of the lead  21   a  serves as the header  22 . The stack of the matching component  46  and the optoelectronic die  44  are disposed on the header  22 . The leadframe has no housing or external package body, so an open space is formed around the optoelectronic die  44 . 
       FIG. 9   b  shows that the leadframe structure is combined with a housing  24 , and an opening  28  is formed at one end of the housing  24 . The stack of the matching component  46  and the optoelectronic die  44  is located on the header  22 , and the optoelectronic die  44  is located opposite the opening  28 . 
       FIG. 9   c  shows that the leadframe structure is combined with a housing  24 , which completely covers the optoelectronic die  44  and the matching component  46 .  FIG. 9   d  shows that a housing  24  completely covers the optoelectronic die  44  and a matching component  46 , wherein a lens structure  54  is formed at one end of the surface of the housing  24  and located opposite the optoelectronic die  44 . The lens could be an epoxy-lens, or an injection-molding-lens. 
       FIG. 3  shows a leadframe structure having the metal or plastic header  32 . Thus, the stack of the optoelectronic die  44  and the matching component  46  may be located on the header  32 . Furthermore, during the process of forming the header  32 , a housing  34  may be injection-molded to combine with the header  32 . Then, the optoelectronic die  44  and the matching component  46  are located in the housing  34  during the packaging process. 
       FIGS. 6   a ,  6   b ,  7   a ,  7   b    8   a  to  8   e  and  9   a  to  9   d  show that the architecture of the stack of the optoelectronic die  44  and the matching component  46  may be adapted to various kinds of TO-can components and leadframe components. In addition, the combined architecture of the optoelectronic device  16  and the housing  14  with the film  48  is the same as that of the above-mentioned embodiment. Also,  FIGS. 8   c  to  8   e  respectively show that the light rays may penetrate through the spherical lens  50 , the flat window  51  and the lens structure  52  on the housing  14 , so these assemblies may be referred to as optical element. However, the optical elements are not limited thereto. Also, the housing chamber  15  is preferably in a hermetically-sealed status via the optoelectronic element is sealed in the housing  14 . The inner atmosphere may be nitrogen. The standard leakage tests include gross and fine leakage tests. The typical sealed condition is defined under fine leakage test by the leak rate lower than 5×10 −5  atm-cc/sec. However, the currently preferred standard can be lower than 5×10 −8  atm-cc/sec. 
     The electrical characteristic of the optoelectronic die  44  stacked on the matching component  46  will be further described in the following. 
       FIGS. 10   a  and  10   b  show that the optoelectronic die  44  is stacked on the matching component  46 . One side of the optoelectronic die  44  has two electrodes (bonding pad regions)  81  and  82 . The other side of the optoelectronic die  44  has a substrate  84 , such as a semi-insulating or insulating layer, adhered to the matching component  46  via an substantially insulative adhesive  85 . Thus, the electrodes (bonding pad regions)  81  and  82  are located in a direction away from the surface of the matching component  46 . 
       FIGS. 10   c  and  10   d  show that the optoelectronic die  44  and the matching component  46  are combined by the flip chip technique. Two electrodes  81  and  82  of the optoelectronic die  44  are located on the same side, and are adhered and electrically connected to the electrodes on the matching component  46  by a conductive adhesive  86  or a solder. 
       FIGS. 10   e  and  10   f  show the optoelectronic die  44  having the vertical architecture. That is, two electrodes  81  and  82  are respectively located on two opposite sides. The electrode  81  is adhered to the matching component  46  via a conductive paste (silver paste)  86 . The electrode (bonding pad region)  82  is located in a direction away from the surface of the matching component  46 , and a wire is connected to the electrode  82  so that the optoelectronic die  44  is electrically connected to the matching component  46 . 
     In fact, the optoelectronic die  44  only occupies a portion of the area of the matching component  46 . Thus,  FIG. 10   g  shows a passive device  87 , such as a capacitor, a resistor, an inductor or any combination thereof, which may be located on the matching component  46 . The electrodes of the passive device  87  may be formed on the same side surface, or opposite sides. For example, the capacitor may be a capacitor having the SMD architecture, or may be a chip capacitor. In addition to the condition, in which the passive device  87  is located on the matching component  46 , an active device, such as a Zener diode, may also be located on the matching component  46 . 
     In detail, the stack of the optoelectronic die  44  and the matching component  46  may increase or optimize the spatial availability of the optoelectronic component so that the size reduction of the optoelectronic component become more practical. 
     Third Type: Optoelectronic Die is Fixed to Header 
       FIG. 11   a  shows that the optoelectronic die  44  is fixed to the surface of the metal header  12  by an adhesive layer  56 . Obviously, this embodiment has no submount.  FIG. 11   b  shows that a thin film  48  covers the surface of the optoelectronic die  44 . This embodiment has no submount. 
       FIG. 11   c  shows that the optoelectronic die  44  is a diode. The optoelectronic die  44  has a P-type metal layer  61 , a semiconductor layer  62 , a substrate  63  and an N-type metal layer  64 , wherein the semiconductor layer  62  has an active region, and the substrate  63  is an N-type substrate. The optoelectronic die  44  having the P-type substrate may also be analogized. 
     The combination of the optoelectronic die  44  and the header  12  is performed by moving the P-type metal layer  61  toward the header  12  with the adhesive layer  56  interposed therebetween. The material of the adhesive layer  56  may be an electroconductive adhesive, such as a metal-filled adhesive, a solder (e.g., AuSn) or a solder paste (e.g. SAC), or a mixture of the electroplated metals with tin and the flux. 
     The above-mentioned adhesive material can be combined with the header  12  without the submount structure, so the adhesive layer  56  can combine the P-type metal layer  61  with the metal header  12 . Even if the adhesive layer  56  overflows, the adhesive layer cannot be adhered to the semiconductor layer  62  after reflow. So, it is possible to prevent the optoelectronic die  44  from becoming device short-circuit. In addition, the P-type metal layer  61  is electrically connected to an electrode pin  65  through the adhesive layer  56 , and the N-type metal layer  64  is electrically connected to another electrode pin  66  through a wire  67 . 
     No submount is used in this embodiment, so the cost can be reduced, the size can be reduced, and the high frequency property of the component can further be improved. The package yield can be enhanced by selecting the suitable material of the adhesive layer  56 . In addition, in the optoelectronic die with the N type substrate, the adopted P-side down packaging structure can transfer the heat, generated by the optoelectronic component, to the header  12  through the adhesive layer  56  and the P-type metal layer  61  more easily so that the heat dissipation of the optoelectronic component can be further improved. 
       FIG. 12  shows that the optoelectronic die  44  has a semi-insulating or insulating substrate  72  with the high impedance (&gt;10 7  ohm-cm). In addition, it includes a P-type metal layer  61 , an N-type metal layer  64  and a semiconductor layer  62 . It is to be noted that a first electrode  73  and a second electrode  74  are formed on the semi-insulating or insulating layer  72  and located on the same surface. 
     The optoelectronic die  44  has the P-side up package type. The semi-insulating or insulating layer  72  corresponds to the header  12 , and the material of the adhesive layer  56  is an electroconductive adhesive or an insulative adhesive. Although the optoelectronic die  44  is directly adhered to the surface of the header  12  by the adhesive layer  56 , no short-circuited condition is caused because the semi-insulating or insulating layer  72  is not electrically connected to the metal header  12 . The above-mentioned architecture may serve as a photo detector  70 . 
       FIG. 13   a  shows that the wire bonding regions of two electrodes  73  and  74  of the photo detector  70  are exposed and located on the surface of the component. So, the user can connect the two wires  75  and  76  respectively to the two electrodes  73  and  74  and a transimpedance amplifier  77 . The transimpedance amplifier  77  converts photocurrent signal into voltage signal, amplifies the amplitude of the voltage signal and outputs the amplified signal. 
       FIG. 13   b  shows that a bypass capacitor  71  may be provided to filter out the high-frequency noise in this embodiment. This design can greatly reduce the capacitance of the bonding pads. Thus, many bonding pads may be provided, or the area of the bonding pad may be enlarged to allow many wire bonding points. The bonding pads are to be connected to PIN+ and PIN− of the TIA pins. 
       FIG. 13   c  shows that a transimpedance amplifier  77  and a postamplifier (Postamp/Limiting Amplifier)  78  may be combined together to form a single chip-type component, which can be electrically connected to the optoelectronic die  44 . The function of the postamplifier  78  is to amplify the differential voltage signal from the transimpedance amplifier  77 , into an output signal with a stable amplitude. Because the transimpedance amplifier  77  and the postamplifier  78  are combined together to form a single chip-type component, it can be electrically connected to the optoelectronic die  44  conveniently. In addition, no submount is used in this embodiment, so the header  12  has the enough space for the mounting of the chip component. Consequently, the implementation of the smaller package structure, containing the header with the smaller area, is indirectly induced, and the requirement of the shorter wire is caused so that the high frequency performance of the component is enhanced. 
     If the optoelectronic die  44  is a light-emitting diode (LED) or a laser diode (LD), a driving and control circuit has to be provided to control the light emitting type. 
       FIG. 14   a  shows a chip-type driver integrated circuit (Driver IC)  79 , which includes a driving and control circuit and is electrically connected to the optoelectronic die (LED or LD)  44 . In this embodiment, the size of the circuit board can be reduced, and the header  12  further can provide the enough space for the mounting of the driver IC  79  because no submount is present. 
       FIG. 14   b  shows that two optoelectronic dies  44  and  44   a  are located on the header  12  or  22 . One of the optoelectronic dies  44  and  44   a  is a LED (or laser diode), and the other one of the optoelectronic dies  44  and  44   a  is a photo detector. The transimpedance amplifier  77 , the postamplifier  78  and the driver  79  may be integrated as an specific IC, which is located on the header  12  and electrically connected to two optoelectronic dies  44  and  44   a.    
     In this embodiment, it is mentioned that the photo detector  70  has the P-side Up package type. After the photo detector  70  is fixed, two electrodes  73  and  74  are exposed to serve as the wire bonding regions. As mentioned hereinabove, the property of the optoelectronic component may be enhanced without the need of the submount. In addition, no submount is provided in the optoelectronic device, so the manufacturing cost can be significantly reduced. The light rays may be emitted and received, and different package types of the P-side down and the P-side up packages may be satisfied by selecting the proper adhesive layer material and using optoelectronic die with the proper architecture. 
       FIG. 15   a  shows that the optoelectronic die  44  is adhered to the header  12 , wherein no housing is located on the header  12 . The surface of the optoelectronic die  44  may be exposed or may be covered by a film. 
     In addition, the combined architecture of the optoelectronic device and the metal housing  14  will be described in the following. The surface of the optoelectronic die  44  is not covered by the thin film  48 . However, the structure, in which the surface of the optoelectronic die  44  is covered by the film  48 , is still the same as that described hereinbelow. 
       FIG. 15   b  shows the header  12  being a TO-can header, wherein a housing  14  is located on the header  12 , and an opening  18  is formed at one end of the housing  14  and located opposite the optoelectronic die  44 . 
       FIG. 15   c  shows a ball lens  50  located at one end of the housing  14  and opposite the optoelectronic die  44 .  FIG. 15   d  shows that a piece of flat window  51  is located on the housing  14  and opposite the optoelectronic die  44 .  FIG. 15   e  shows a lens structure  52 , such as an epoxy lens, located at one end of the housing  14  and opposite the optoelectronic die  44 . 
       FIG. 16   a  shows the optoelectronic device without the submount, wherein its optoelectronic die  44  is adhered to one end of one frame  21  of the leadframe architecture. Based on the direction in the drawing, no housing or package body is located at first ends of two leads  21   a  and  21   b . Also, the surface of the optoelectronic die  44  may be exposed or covered by a film (not shown). 
     The combined architecture of the optoelectronic device and the resin housing  24  without the submount will be described in the following. The surface of the optoelectronic die  44  may not be covered by the thin film  48 . However, the structure, in which the surface of the optoelectronic die  44  is covered by the thin film  48 , is still the same as that mentioned hereinbelow. 
       FIG. 16   b  shows a housing  24  formed at the end portions of the leads  21   a  and  21   b , wherein an opening  28  is formed on the housing  24  and located opposite the optoelectronic die  44 .  FIG. 16   c  shows that the housing  24  with the closed structure is located at first ends of the leads  21   a  and  21   b .  FIG. 16   d  shows that the housing  24  with the closed structure is located at first ends of the leads  21   a  and  21   b , and a lens  54  is formed on the housing  24  and located opposite the optoelectronic die  44 . 
       FIG. 17   a  shows that the optoelectronic die  44  is adhered to the header  32  and that no housing is located around the optoelectronic die  44 . The header  32  may be a plastic headerplate or metal headerplate. Taking the plastic material as an example, the header  32  is formed on the frames  31   a  and  31   b  by way of injection molding. The optoelectronic die  44  is adhered to the header  32  and electrically connected to the frame  31   a.    
       FIG. 17   b  shows that a housing  34  is located on the header  32 . More particularly, the housing  34  and the header  32  are formed on the leads  31   a  and  31   b  by way of injection molding. The optoelectronic die  44  may be an edge emitting component or a surface-emitting component. 
     The surface of the optoelectronic die  44  in each of  FIGS. 17   a  and  17   b  may be covered by a thin film  48  or may be exposed. 
     The matching component  46  located in the optoelectronic device  16 ,  26  or  36  may be a transimpedance amplifier, a postamplifier, a driver integrated circuit, a passive device (e.g., resistor, capacitor or inductor), an active device (e.g., Zener diode) located on the header or any combination thereof. The passive or active device provides at least one of the anti-surge function, voltage transforming function, rectifying function, voltage regulating function, sensing function, feedback circuit function and impedance matching function. 
     Also, the optoelectronic die  44  may be a LED or a LD for emitting light rays; or may be a photo detector (or photodiode, hereinafter referred to as PD) for receiving light rays. The optoelectronic die  44  is applied to the optical fiber communication of the glass optical fiber, which emits or receives the infrared optical signal with the wavelength ranging from 800 nm to 1800 nm. When the optoelectronic die  44  is applied to the optical fiber communication with the plastic optical fiber, it emits or receives the visible light optical signals having the wavelength ranging from 200 nm to 800 nm. 
     Also, the film  48  is made of a material, such as a polymeric material or adhesive, with the low viscosity coefficient lower than 5000 cps (like Karo Syrup). Alternatively, the film  48  may be made of the material having a viscosity coefficient lower than 100 cps, but in some cases higher than 1 cps (water). After the material properly volatilizes, the film is ultra thin, and typically has thickness of less than 2 micrometers and preferably less than 1 micrometer over the major portion of covered surface, and tends to have the uniform conformal coating effect, which is advantageous to the optoelectronic die  44  in resisting the component property deterioration caused by the high temperature and the high humidity environment. In addition, the optical property variations of the optoelectronic devices  16 ,  26  and  36  may be reduced. In other words, covering the film  48  over the optoelectronic die  44  and/or the surface of the matching component  46  is advantageous to the improvement of the component reliability. 
     The polymeric material of the film  48  is preferably a fluoro-polymer having the corresponding solvent of methoxy-nonafluorobutane with the molecular formula of C 4 F 9 OCH 3 . The fluoro-polymer may be one of a fluorochemical acrylate polymer, a fluorosilane polymer, a fluoroaliphatic polymer, a methyl nonafluoroisobutyl ether, a methyl nonafluorobutyl ether and other similar materials, or any combination thereof. The selected solvent needs to have the low boiling point (lower than 65° C. is preferred), and after its mixed solution covers the component and properly volatilizes to form a dry film, the surface energy of the dry film ranges from 10 to 15 dynes/cm. Under a predetermined condition, the thickness of the volatilized film may be reduced to around 1 micrometer, even to 0.1, 0.01 micrometer or less, depending on the application environment. In some cases, the film still has the effect of preventing the component from deteriorating, especially in the damp heat environment. 
     In one method of covering the polymeric material over the optoelectronic die, a semiconductor optoelectronic die is immersed in a dilute polymeric material, and then the optoelectronic die is taken out to dry the polymeric material. The dip coating could be done at room temperature without oven curing. Consequently, the dried polymeric material may be formed into a polymeric film covering the surface of the optoelectronic die. 
     In another method of covering the polymeric material over the optoelectronic die, the polymeric material is dropped into the chamber through the cup-like container formed by the opening of the housing of the optoelectronic component so that the polymeric material can cover the surface of the optoelectronic die and/or the surface of the matching component. After the polymeric material properly volatilizes, a film is formed to cover the surface of the optoelectronic die and/or the surface of the matching component. Sometimes, the film only covers the surface of the matching component but does not completely cover the optoelectronic die to protect the fragile III-V component, e.g., GaAs or InP chip/IC to reduce the influence of the optical and/or electrical property of the optoelectronic die. 
     The architecture of the optical sub-assembly is the combination of one optoelectronic component and one barrel. The architecture of the optoelectronic component has been mentioned hereinabove. The architecture of the barrel will be described in the following. 
       FIGS. 18   a  to  18   d  show four examples of the various barrels  90  each having a chamber  92  and an optical fiber channel  94 . 
     As shown in  FIG. 18   a , an accommodating channel  96  is located between the barrel chamber  92  and the optical fiber channel  94  of the barrel  90 , and at least one lens  100  may be located in the accommodating channel  96 . 
     As shown in  FIG. 18   b , an end surface of the barrel chamber  92  is a first surface  97 , and a first lens  111  is formed on the first surface  97 . 
     As shown in  FIG. 18   c , the bottom of the optical fiber channel  94  has a second surface  98 , and a second lens  112  is formed on the second surface  98 . 
     As shown in  FIG. 18   d , a first lens  111  is formed on the first surface  97  of the chamber  92 , and the second surface  98  of the optical fiber channel  94  is formed with a second lens  112  located opposite the first lens  111 . 
     It is to be noted that any one of the barrels  90  of  FIGS. 18   a  to  18   d  can be a unit either by single plastic injection molding or by combining metal receptacle and plastic/glass lens/lenses, wherein a flat window surface can also be treated as a lens with an unlimited radius of curvature. Each may be combined with the optoelectronic component  10 , or  30  so that the optical sub-assembly for optical communication may be formed and may be mounted on the signal transmitting end or the signal receiving end of the optical fiber according to the requirement. It is also noted that the first and second surface are preferably closed surfaces. 
     The details of the architecture of the optical sub-assembly will be described in the following. 
       FIG. 19   a  shows that the optoelectronic component  10  with the TO-can architecture is combined with a barrel  90  to form an optical sub-assembly. The barrel  90  has the first lens  111  and the second lens  112 . The housing  14  of the optoelectronic component  10  is inserted into the barrel chamber  92 , and an adhesive agent  120  adheres the external side surface of the housing  14  to the inner wall surface of the barrel chamber  92  so that the space constituted by the barrel chamber  92  and the housing chamber  15  of the housing  14  is preferably in a hermetically-sealed status. The sealed space structure can prevent the optoelectronic device  16  from being influenced by the external environment. Furthermore, the airtight space can be vacuumed or filled with a stable gas, like Nitrogen. 
     Also, the first lens  111  is located opposite the optoelectronic device  16 , so the optical coupling effect between the optoelectronic device  16  and the first lens  111  may be increased by extending the first lens  111  toward the optoelectronic device  16 , especially by extending the first lens  111  through the opening  18 . 
       FIG. 19   b  shows that the thin film  48  may cover the surface of the optoelectronic device  16 . The covering region of the thin film  48  includes a portion of or a whole surface of the optoelectronic device  16 . In addition, the first lens  111  may penetrate through the opening  18  and thus further approach the optoelectronic device  16  with an optimized result of the efficiency so that the optical coupling effect between the optoelectronic device  16  and the first lens  111  may be enhanced. 
       FIG. 19   c  shows the optoelectronic component (shown as  FIG. 11   b ) is combined with a barrel  90  to form an optical subassembly, wherein the optoelectronic die  44  of the optoelectronic component  10  is fixed on the header  12 , and the thin film  48  is covered on the optoelectronic die  44 . The barrel chamber  92  is preferably in a hermetically-sealed status, which is not a must under the thin film covered. The same concept could be applied to To-can embodiment, which comprises an optoelectronic die fixed on the header (a submount, a matching component or both may be interposed between), and a housing with an optical element combined with the header. 
     According to the teachings mentioned hereinabove, the optoelectronic component may have the TO-can architecture as well as the leadframe architecture. In addition, the thin film  48  may cover the optoelectronic die  44  or may be omitted. 
     The optoelectronic component may be any optoelectronic component mentioned in this specification, and the optoelectronic device further includes an optoelectronic die located on the matching component, or an optoelectronic die located on the submount. Alternatively, the optoelectronic die may be adhered to the header without the submount structure, and the portion of the lens is not restricted to whether the integrally formed member is formed or whether the lens is mounted thereafter. 
     In addition,  FIG. 20   a  shows an embodiment, in which the optoelectronic component with the TO-can architecture is combined with the barrel. In this embodiment, an index matching oil  130  is provided to fill the internal space of the housing  14  and/or the barrel chamber  92 . Thus, a smaller diverging angle may be obtained when the optical signal travels between the optoelectronic device  16  and the first lens  111  so that the optical coupling effect can be enhanced, and the effect of protecting the optoelectronic device  16  may be obtained. The index matching oil  130  may be replaced with a glue having the fixing and protecting properties. 
       FIG. 20   b  shows an embodiment, in which the optoelectronic component with the leadframe architecture is combined with the barrel. In this embodiment, the index matching oil  130  is filled into the barrel chamber  92 , and then the optoelectronic component  20  is inserted into the barrel chamber  92  so that the optoelectronic component  20  is combined with the barrel  90 . Thus, a smaller diverging angle may be obtained to enhance the optical coupling effect when the optical signal travels between the optoelectronic device  26  and the first lens  111 . In addition, the index matching oil  130  also has the effect of protecting the optoelectronic device  26 . 
       FIG. 20   c  shows that the optoelectronic component with the TO-can architecture is combined with the barrel. In this embodiment, a glue  132  with the fixing and protecting properties is filled into the housing  14 , and the filling height of the glue  132  ranges between the top surface of the optoelectronic device  16  and the top surface of the header  12  to form the structure pattern of partially covering the optoelectronic device  16 . Thus, the effects of protecting the adhesive material and the optoelectronic device  16  may be obtained. 
       FIG. 20   d  shows that the glue  132  partially covers the optoelectronic device  16 . The glue  132  further completely covers the top surface of the matching component  46  (e.g., transimpedance amplifier, postamplifier, driver integrated circuit, passive device or active device) and does not cover the top surface of the optoelectronic die  44 . 
       FIG. 20   e  shows that the glue  132  is filled into the internal space of the housing  14 , and the filling height of the glue  132  exceeds the top surface of the optoelectronic device  16  to complete cover the optoelectronic device  16 . Thus, the effects of protecting the adhesive material and the optoelectronic device  16  may be obtained. 
       FIG. 20   f  shows that the glue  132  is filled in the barrel chamber  92  of the barrel  90  and does not flow over the first lens  111 . When the optoelectronic component  10  is inserted into the barrel chamber  92 , the glue  132  is adhered to the end portion of the housing  14  so that the housing  14  is preferably hermetically-sealed and the glue  132  does not contact the optoelectronic device  16 . 
       FIG. 20   g  shows that the glue  132  is coated on the optoelectronic device  16 , and that the glue  132  completely or partially covers the optoelectronic device  16 . 
     In the optical sub-assembly of the invention, the first lens may penetrate through the opening to approach the optoelectronic device. Consequently, the optoelectronic device may not have the submount, and the first lens still can approach the optoelectronic die. So, the optical coupling efficiency can be optimized. In addition, using the index matching oil can converge the diverging angle of the light and achieve the effect of increasing the optical coupling efficiency. Also, filling the index matching oil or glue can achieve the effect of protecting the optoelectronic component. In addition, the optoelectronic component, especially the optoelectronic component with the TO-can architecture, has the lowered manufacturing cost because the metal housing has no glass piece or spherical lens. Thus, the low-cost advantage is still obtained after the optical sub-assembly is formed. 
     However, when the glue  132  is made of the epoxy, silicone, urethane or acrylic material, the thick film having the thickness greater than several tens of micrometers tends to be formed, and the glue or the index matching oil may generate bubbles and the inconsistent curvatures, especially in mass production. Nevertheless, the use of the glue or the index matching oil can protect the material and enhance the optical coupling at the expense of manufacturability. However, if the polymeric material (e.g., the fluoro-polymer) of the embodiment having the low viscosity coefficient is coated on the surface of the optoelectronic die and naturally volatilizes, the influence factors mentioned hereinabove may be improved with respect to the optoelectronic component, and the consistency of the property of the optoelectronic component may further be enhanced. 
     Next, in the embodiment wherein the thickness of the film is preferably less than 1 micrometers, the thickness is directed to the thickness of the film of most of the region above the active region of the optoelectronic die. Usually, the thickness of the film in the vicinity of the wire or on the other corners may be locally increased without affecting optical property and deviating from the equivalent scope of the invention. 
     Furthermore, types of barrel structures, the TO-can or the leadframe architecture with an opening or any kind of optical element, the matching component, the optoelectronic device having the submount or not, the coating of the material with a low viscosity coefficient or not (including the coating method, the thickness selection or the material selection), the sealed condition of the chamber formed in the barrel and the housing or not, or the stacked and arranged manner of the optoelectronic die and the matching component may be modified according to various kinds of market requirements. Herein, only several embodiments are illustrated, and any combination or slight modification may still fall within the scope of the invention. 
     While the invention has been described by way of examples and in terms of preferred embodiments, it is to be understood that the invention is not limited thereto. To the contrary, it is intended to cover various modifications. Therefore, the scope of the appended claims should be accorded the broadest interpretation so as to encompass all such modifications.