Abstract:
An optical module comprising: an optical fiber; an optical element having an optical section and with a fixed position relative to the optical fiber; and a semiconductor chip electrically connected to the optical element, and the optical element and semiconductor chip being packaged. A hole is formed in the semiconductor chip, and the optical element is mounted on the semiconductor chip with the optical section facing the hole, and the optical fiber is inserted in the hole and fitted to the semiconductor chip.

Description:
BACKGROUND OF THE INVENTION  
         [0001]    1. Field of the Invention  
           [0002]    The present invention relates to an optical module and method of manufacture thereof, to a semiconductor device, and to an optical transmission device.  
           [0003]    2. Description of Related Art  
           [0004]    In recent years, there has been a trend toward increased speeds and volumes in data communications, and developments in optical communications continue. Generally, in optical communications, an electrical signal is converted to an optical signal, the optical signal is transmitted through an optical fiber, and then the received optical signal is converted to an electrical signal. The conversion between electrical signals and optical signals is done by optical elements.  
           [0005]    For example, Japanese Patent Application Laid-Open No. 10-339824 discloses an optical fiber positioned and fixed on a platform in which a V-groove is formed, to constitute an optical module.  
           [0006]    However, a conventional optical module has an optical fiber and optical element formed integrally, and it is further necessary to electrically connect this optical module to a semiconductor chip.  
         SUMMARY OF THE INVENTION  
         [0007]    The present invention solves this problem, and has as its objective the provision of an optical module not requiring connection to a semiconductor chip and method of manufacture thereof, of a semiconductor device and of an optical transmission device.  
           [0008]    (1) According to a first aspect of the present invention, there is provided an optical module of the present invention comprising:  
           [0009]    an optical waveguide;  
           [0010]    an optical element having an optical section; and  
           [0011]    a semiconductor chip electrically connected to the optical element,  
           [0012]    wherein the optical element and the semiconductor chip are packaged.  
           [0013]    According to this aspect of the present invention, the optical element and semiconductor chip are packaged, and the semiconductor chip is incorporated into the optical module. Therefore, further connection of the optical module to a semiconductor chip is not required, and handling is made easier.  
           [0014]    (2) In this optical module, a hole may be formed in the semiconductor chip; the optical waveguide may be inserted into the hole; and the optical element may be disposed so that the optical section and one end surface of the inserted optical waveguide are opposed.  
           [0015]    By means of this, the optical waveguide is positioned by the hole formed in the semiconductor chip, and therefore the positioning accuracy of the optical section of the optical element and the end surface of the optical waveguide is increased.  
           [0016]    (3) In this optical module, the hole may be a through hole.  
           [0017]    (4) In this optical module, a light-transmitting sealant may be provided at the through hole.  
           [0018]    By means of this, the optical waveguide is contacted with the sealant, and the positioning achieved.  
           [0019]    (5) In this optical module, an underfill material may be provided between the optical element and the semiconductor chip.  
           [0020]    By means of this, the optical element and semiconductor chip are protected, and also the connection therebetween can be made stable.  
           [0021]    (6) In this optical module, an interconnect pattern may be formed on the semiconductor chip; a plurality of electrodes may be formed on the optical element; and at least one of the plurality of electrodes may be electrically connected to the interconnect pattern.  
           [0022]    By means of this, since the optical element is mounted on the semiconductor chip, the optical module can be made more compact. To the semiconductor material constituting the semiconductor chip, the method of manufacture of the semiconductor device can be applied, and an interconnect pattern of high accuracy can be formed.  
           [0023]    (7) This optical module may further comprise a substrate for supporting at least either of the semiconductor chip and the optical element.  
           [0024]    (8) In this optical module, the substrate may assist the dispersion of heat from at least either of the semiconductor chip and the optical element.  
           [0025]    (9) This optical module may further comprise external terminals provided on the substrate, and electrically connected to at least either of the optical element and the semiconductor chip.  
           [0026]    (10) In this optical module, the semiconductor chip and the optical element may be sealed with resin.  
           [0027]    By means of this, the semiconductor chip and optical element are protected by the resin.  
           [0028]    (11) According to a second aspect of the present invention, there is provided a semiconductor device comprising: an optical element having an optical section; and a semiconductor chip electrically connected to the optical element, wherein the optical element and the semiconductor chip are packaged.  
           [0029]    According to this aspect of the present invention, since the optical element and semiconductor chip are packaged, further connection of the optical module and semiconductor chip is not required, and handling is made easier.  
           [0030]    (12) In this semiconductor device, the optical element and the semiconductor chip may be stacked.  
           [0031]    (13) In this semiconductor device, a hole may be formed in the semiconductor chip; the optical element may be disposed so that one end surface of the semiconductor chip and the optical section are opposed; and the optical element and the semiconductor chip may be stacked.  
           [0032]    (14) In this semiconductor device, the optical element and the semiconductor chip may be disposed on a substrate.  
           [0033]    (15) In this semiconductor device, a hole may be formed in the substrate; the optical element may be disposed so that one end surface of the semiconductor chip and the optical section are opposed; and the optical element may be disposed on the substrate.  
           [0034]    (16) According to a third aspect of the present invention, there is provided an optical transmission device comprising:  
           [0035]    an optical waveguide;  
           [0036]    a light-emitting element mounted with a light-emitting section facing one end surface of the optical waveguide;  
           [0037]    a semiconductor chip electrically connected to the light-emitting element and packaged with the light-emitting element;  
           [0038]    a light-receiving element mounted with a light-receiving section facing the other end surface of the optical waveguide; and  
           [0039]    a semiconductor chip electrically connected to the light-receiving element and packaged with the light-receiving element.  
           [0040]    According to this aspect of the present invention, the light-emitting element or light-receiving element and the semiconductor chip are packaged, and incorporate a semiconductor chip. Therefore, further connection between the light-emitting element or light-receiving element and the semiconductor chip is not required, and handling is made easier.  
           [0041]    (17) This optical transmission device may further comprise: a plug connected to the light-emitting element; and a plug connected to the light-receiving element.  
           [0042]    (18) According to a fourth aspect of the present invention, there is provided a method of manufacture of an optical module having at least an optical waveguide, an optical element having an optical section, and a semiconductor chip. This method comprises the steps of:  
           [0043]    electrically connecting the optical element and the semiconductor chip;  
           [0044]    relatively positioning the optical waveguide and the optical element; and  
           [0045]    packaging the optical element and the semiconductor chip.  
           [0046]    According to this aspect of the present invention, the optical element and semiconductor chip are packaged, and further connection of the optical module obtained to a semiconductor chip is not required, and handling is made easier.  
           [0047]    (19) In this method of manufacture of an optical module, an interconnect pattern may be formed on the semiconductor chip; the optical element may have a plurality of electrodes; and the step of electrically connecting the optical element and the semiconductor chip may bond at least one of the plurality of electrodes to the interconnect pattern.  
           [0048]    By means of this, merely by bonding the electrodes to the interconnect pattern, the electrical connection between the optical element and semiconductor chip can be achieved simply. Since the optical element is mounted on the semiconductor chip, the optical module can be made more compact. To the semiconductor material constituting the semiconductor chip, the method of manufacture of the semiconductor device can be applied, and an interconnect pattern of high accuracy can be formed.  
           [0049]    (20) In this method of manufacture of an optical module, the electrode and the interconnect pattern may be bonded with a soldering material; and the positions of the optical element and semiconductor chip may be determined by the surface tension of the fused soldering material.  
           [0050]    By means of this, by the surface tension of the soldering material the positioning of the optical element and semiconductor chip is carried out, and therefore a positioning step is not required.  
           [0051]    (21) In this method of manufacture of an optical module, a hole may be formed in the semiconductor chip; and the step of relatively positioning the optical waveguide and the optical element may include a step of inserting the optical waveguide into the hole.  
           [0052]    By means of this, by inserting the optical waveguide into the hole, the positioning of the optical waveguide and semiconductor chip is determined. Therefore, if the positioning of the optical element and semiconductor chip is carried out, the positioning of the optical element and optical waveguide can be carried out simply.  
           [0053]    (22) In this method of manufacture of an optical module, the hole may be formed by a laser.  
           [0054]    (23) In this method of manufacture of an optical module, the hole may be formed by etching.  
           [0055]    (24) This method of manufacture of an optical module may further comprise a step of forming a depression in the region in which the hole is to be formed in the semiconductor chip by anisotropic etching, and then penetrating the depression by a laser, to form the hole in the semiconductor chip.  
           [0056]    Anisotropic etching is widely carried out by the process of manufacture of a semiconductor device, and allows a depression of high accuracy to be formed. By means of anisotropic etching, the cross-section of the depression forms a V-shape, and therefore a hole formed by penetrating the depression with a laser has opening extremities which are tapered. Therefore, a hole with tapered opening extremities can be formed simply. The hole taper acts as a guide when the optical waveguide is inserted.  
           [0057]    (25) This method of manufacture of an optical module may further comprise a step of providing an underfill material between the semiconductor chip and the optical element.  
           [0058]    By means of this, by means of the underfill material, the optical element and semiconductor chip can be protected, and also the connection therebetween can be made stable.  
           [0059]    (26) In this method of manufacture of an optical module, the step of packaging the optical element and the semiconductor chip may comprise sealing the optical element and the semiconductor chip with a resin.  
           [0060]    By means of this, the semiconductor chip and optical element can be protected by the resin.  
           [0061]    (27) This method of manufacture of an optical module may further comprise a step of providing a substrate to at least either of the semiconductor chip and the optical element.  
           [0062]    (28) This method of manufacture of an optical module may further comprise a step in which external terminals electrically connected to at least either of the optical element and the semiconductor chip are provided on the substrate. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0063]    [0063]FIG. 1 shows a first embodiment of an optical module to which the present invention is applied;  
         [0064]    [0064]FIGS. 2A to  2 C show a method of forming a hole in a semiconductor chip;  
         [0065]    [0065]FIG. 3 shows a second embodiment of an optical module to which the present invention is applied;  
         [0066]    [0066]FIG. 4 shows a third embodiment of an optical module to which the present invention is applied;  
         [0067]    [0067]FIG. 5 shows a fourth embodiment of an optical transmission device to which the present invention is applied;  
         [0068]    [0068]FIG. 6 shows a fifth embodiment of an optical transmission device to which the present invention is applied;  
         [0069]    [0069]FIG. 7 shows a sixth embodiment of an optical module to which the present invention is applied; and  
         [0070]    [0070]FIG. 8 shows a seventh embodiment of an optical module to which the present invention is applied.  
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0071]    The present invention is now described in terms of a number of preferred embodiments, with reference to the drawings.  
         [0072]    First Embodiment  
         [0073]    [0073]FIG. 1 shows a first embodiment of an optical module to which the present invention is applied. The optical module comprises an optical element  10 , a semiconductor chip  20 , and an optical fiber  30 . The optical fiber  30  is an example of an optical waveguide. Since this optical module includes the semiconductor chip  20 , it may also be defined as a semiconductor device. This applies similarly to all of the below embodiments.  
         [0074]    The optical element  10  may be a light-emitting element or a light-receiving element. As an example of a light-emitting element may be used a surface emitting element, and particularly a surface emitting laser. A surface emitting element such as a surface emitting laser emits light in a direction perpendicular to the substrate. The optical element  10  includes an optical section  12 . When the optical element  10  is a light-emitting element, the optical section  12  is a light-emitting section, and when the optical element  10  is a light-receiving element, the optical section  12  is a light-receiving section.  
         [0075]    The optical element  10  is fixed in relative position with respect to the optical fiber  30 . More specifically, the optical section  12  of the optical element  10  and the end surface of the optical fiber  30  are preferably fixed in relative position. In more concrete terms, the optical section  12  is commonly disposed to oppose the end surface of the optical fiber  30 . In this embodiment, the optical section  12  faces a hole  28  in the semiconductor chip  20 .  
         [0076]    The optical element  10  has at least one (generally two or more) electrodes. For example, on the surface on which the optical section  12  is formed, first electrodes  14  may be provided. It should be noted that of the plurality of first electrodes  14 , at least one may be a dummy electrode. A dummy electrode may be formed of the same material as the first electrodes  14 , but has no electrical connection within the optical element  10 . For example, when the first electrodes  14  are formed such that if joined by straight lines they form a polygon of at least three sides, one or more thereof may be dummy electrodes. By this means, the optical element  10  can be stably supported with at least three points of fixture.  
         [0077]    On a surface different from the surface on which the first electrodes  14  are provided, second electrodes  16  may be provided. When the optical element  10  is a surface light-emitting laser or other semiconductor laser, the second electrodes  16  may be provided on the opposite surface to the surface on which the first electrodes  14  are provided.  
         [0078]    The semiconductor chip  20  is for driving the optical element  10 . The semiconductor chip  20  has an internal circuit for driving the optical element  10 . On the semiconductor chip  20  are formed a plurality of electrodes (or pads)  22  which are electrically connected to the internal circuit. On the surface on which the electrodes  22  are formed, an interconnect pattern  24  electrically connected to at least one electrode  22  is preferably formed.  
         [0079]    The semiconductor chip  20  and optical element  10  are electrically connected. For example, the first electrodes  14  of the optical element  10  and the interconnect pattern  24  formed on the semiconductor chip  20  are electrically connected. For the connection, wires or the like may be used, or a metal bond of solder  26  or the like as a soldering material, or the first electrodes  14  and the interconnect pattern  24  may be bonded with an anisotropic conductive material (film) interposed. In this case, the optical element  10  is mounted face-down on the semiconductor chip  20 . By means of this, not only can the electrical connection be made by the solder  26 , but also the optical element  10  and semiconductor chip  20  can be fixed by the solder  26 . It should be noted that of the first electrodes  14 , those which are dummy electrodes are also preferably connected to the interconnect pattern  24 . By means of this, the optical element  10  can be fixed to the semiconductor chip  20  in a stable state.  
         [0080]    The second electrodes  16  of the optical element  10  and the interconnect pattern  24  are electrically connected. For the connection, wires  27  or the like may be used, or a conductive paste may be provided from the second electrodes  16  to the interconnect pattern  24 .  
         [0081]    Between the optical element  10  and semiconductor chip  20 , an underfill material  40  may be provided. When the underfill material  40  covers the optical section  12  of the optical element  10 , it is preferable for the underfill material  40  to be transparent. The underfill material  40  covers and protects the electrical connection between the optical element  10  and the semiconductor chip  20 , and also protects the surface of the optical element  10  and semiconductor chip  20 . Furthermore, the underfill material  40  maintains the bonding between the optical element  10  and semiconductor chip  20 .  
         [0082]    In the semiconductor chip  20 , a hole (such as a through hole)  28  may be formed. The optical fiber  30  passes through the hole  28 . The hole  28  is formed to avoid the internal circuit, and to extend from the surface where the electrodes  22  are formed to the opposite surface. In the hole  28  may be provided a light-transmitting sealant  25  in the opening of the surface in which the electrodes  22  are formed. By providing the sealant  25  one end of the hole  28  is sealed, and positioning of the end of the optical fiber  30  can be achieved. The sealant  25  can be provided by forming the hole  28  from the surface (the rear surface) opposite to the surface on which the sealant  25  is provided, and leaving a passivation film of SiO 2 , or SiN x , or the like formed on the surface (the front surface) on which the sealant  25  is provided. At at least one opening extremity of the hole  28 , a taper  29  is preferably formed. By forming the taper  29 , it is made easier to insert the optical fiber  30  into the hole  28 .  
         [0083]    The semiconductor chip  20  may be mounted on a substrate  42 . More specifically, the semiconductor chip  20  may be adhered to the substrate  42  by an adhesive  44 . In the substrate  42  a hole  46  is formed. The hole  46  is formed in a position to communicate with the hole  28  in the semiconductor chip  20 . The adhesive  44  adhering the semiconductor chip  20  and the substrate  42  is provided so as not to block the two holes  28  and  46 , in order not to impede communication therebetween. The hole  46  in the substrate  42  is formed with a taper so as to have an internal diameter which is larger on the side opposite to the semiconductor chip  20 . By means of this, it is made easier to insert the optical fiber  30 .  
         [0084]    The substrate  42  may be formed of an insulating material such as resin, glass, or ceramic, but may also be formed of a conductive material such as metal. When the substrate  42  is of a conductive material, at least on the surface on which the semiconductor chip  20  is attached, an insulating film  43  is preferably formed. It should be noted that in the below embodiments also, similar materials can be used for the substrate  42 .  
         [0085]    The substrate  42  preferably has high thermal conductivity. According to this, the substrate  42  assists the dispersion of heat from at least one of the optical element  10  and semiconductor chip  20 . In this case, the substrate  42  is a heat sink or heat spreader. In this embodiment, since the semiconductor chip  20  is adhered to the substrate  42 , the semiconductor chip  20  can be cooled directly. It should be noted that the adhesive  44  adhering the semiconductor chip  20  and substrate  42  is preferably thermally conductive. Furthermore, since the semiconductor chip  20  is cooled, the optical element  10  bonded to the semiconductor chip  20  is also cooled.  
         [0086]    On the substrate  42  is provided an interconnect pattern  48 . On the substrate  42  are provided external terminals  50 . In this embodiment, the external terminals  50  are leads. The interconnect pattern  48  formed on the substrate  42  is connected, for example by wires  52 , to at least one of the electrodes  22  of the semiconductor chip  20 , the interconnect pattern  24  formed on the semiconductor chip  20 , and the first and second electrodes  14  and  16  of the optical element  10 . The interconnect pattern  48  may be electrically connected to the external terminals  50 .  
         [0087]    The optical fiber  30  includes a core and a cladding which concentric-circularly surrounds the core, so that light is reflected by the boundary between the core and the cladding, trapped within the core, and thus transmitted. The periphery of the cladding is commonly protected by a jacket.  
         [0088]    The optical fiber  30  is inserted into the hole  28  in the semiconductor chip  20 . The optical section  12  of the optical element  10  faces into the hole  28  in the semiconductor chip  20 . Therefore, the optical fiber  30  inserted into the hole  28  is positioned with respect to the optical section  12 .  
         [0089]    The optical fiber  30  is also passed through the hole  46  in the substrate  42 . The hole  46  has an internal diameter that gradually decreases toward the hole  28  in the semiconductor chip  20 , and on the surface opposite to that of the semiconductor chip  20 , the internal diameter of the opening of the hole  46  is larger than the optical fiber  30 . The gap between the optical fiber  30  and the internal surface of the hole  46  is preferably filled with a filling material  54  such as resin. The filling material  54  fixes the optical fiber  30  and also functions to prevent its removal.  
         [0090]    In this embodiment, the optical element  10  and semiconductor chip  20  are sealed with a resin  56 . The resin  56  also seals the electrical connection between the optical element  10  and the semiconductor chip  20  and the electrical connection between the semiconductor chip  20  and the interconnect pattern  48  formed on the substrate  42 .  
         [0091]    With this embodiment of the optical module, the optical element  10  and semiconductor chip  20  are packaged. Therefore, since it is not always necessary to make a connection of the driver circuit to the optical module, handling is made easier.  
         [0092]    This embodiment has the above described construction, and the method of manufacture thereof is now described.  
         [0093]    First, an optical element  10 , semiconductor chip  20 , and optical fiber  30  are prepared. The optical element  10  comprises an optical section  12 , and first and second electrodes  14  and  16 . On the semiconductor chip  20 , preferably on the surface on which the electrodes  22  are formed, the interconnect pattern  24  may also be formed. The hole  28  may be formed in the semiconductor chip  20 . Preferably the interconnect pattern  24  and hole  28  of the semiconductor chip  20  are formed with accurate relative positioning.  
         [0094]    The method of forming the hole  28  is now described with reference to FIGS. 2A to  2 C. These figures show a vertical sectional view passing through the location of formation of the hole  28  in the semiconductor chip  20 . As shown in FIG. 2A, a depression  21  is formed in the semiconductor chip  20 . The depression  21  is formed in the location of the opening of the hole  28 . Preferably, the depression  21  is formed in both surfaces in which the hole  28  opens. The semiconductor chip  20  is commonly constructed of silicon, and therefore anisotropic etching can be applied to form the depression  21  with a triangular vertical-section accurately along the crystal planes. Alternatively, the depression  21  may be formed with a rectangular vertical-section. The form of the opening of the depression  21  is not particularly restricted, but it may be rectangular. When the opening of the depression  21  is rectangular, the length of one side is preferably more than the diameter of the optical fiber  30 . By means of this, at least a part of the depression  21  can form the taper  29 .  
         [0095]    Next, as shown in FIG. 2B, the semiconductor chip  20  is bored between the pair of depressions  21  on mutually opposite sides. For example, a laser can be used. That is to say, laser light can be beamed into one depression  21 , and the semiconductor chip  20  bored. Further, to the hole bored between the pair of depressions  21 , etching is applied, to increase the diameter of the hole, and form the hole  28  as shown in FIG. 2C. It should be noted that at least a part of the depression  21  is preferably left remaining at the opening of the hole  28 . By means of this, at least a part of the depression  21  can form the taper  29 .  
         [0096]    Alternatively, the optical excitation electropolishing method can be applied to the formation of the hole  28 .  
         [0097]    This embodiment includes a step of electrically connecting the optical element  10  and semiconductor chip  20 . For example, the first electrodes  14  of the optical element  10  and the interconnect pattern  24  formed on the semiconductor chip  20  are bonded. Alternatively, the first electrodes  14  and the electrodes  22  formed on the semiconductor chip  20  are bonded.  
         [0098]    As a means of bonding, if solder  26  is used, a self-alignment effect is obtained. That is to say, when molten solder  26  is interposed between the first electrodes  14  and the interconnect pattern  24  or the electrodes  22 , the surface tension of the molten solder  26  automatically positions the optical element  10 . On the interconnect pattern  24  it is preferable for lands to be formed on which the solder  26  is provided. The positioning of the optical element  10  is carried out by the self-alignment effect, and therefore the optical section  12  of the optical element  10  can be automatically faced to the hole  28  in the semiconductor chip  20 .  
         [0099]    The second electrodes  16  of the optical element  10  and the interconnect pattern  24  formed on the semiconductor chip  20  are electrically connected. For the connection, wires  27  can be used.  
         [0100]    This embodiment includes a step of attaching at least either of the optical element  10  and semiconductor chip  20  to the substrate  42 . For example, using the adhesive  44 , the semiconductor chip  20  is adhered to the substrate  42 . When the hole  28  is formed in the semiconductor chip  20 , the hole  46  in the substrate  42  communicates with the hole  28  in the semiconductor chip  20 .  
         [0101]    This embodiment includes a step of providing external terminals  50  on the substrate  42 . In this embodiment, leads being the external terminals  50  are provided on the substrate  42 , and are electrically connected to the interconnect pattern  48 . The external terminals  50  are electrically connected to at least either of the optical element  10  and semiconductor chip  20  through the interconnect pattern  48 .  
         [0102]    This embodiment includes a step of relatively positioning and disposing the optical element  10  and optical fiber  30 . For example, the optical fiber  30  is inserted in the hole  28  formed in the semiconductor chip  20 . It should be noted that if the taper  29  is formed at the opening of the hole  28 , the optical fiber  30  can be inserted more easily. If the hole  46  in the substrate  42  is formed so as to enlarge toward the surface from which the optical fiber  30  is inserted, the optical fiber  30  can be inserted more easily.  
         [0103]    Simply by inserting the optical fiber  30  in the hole  28 , the positioning of the optical fiber  30  and semiconductor chip  20  can be carried out. If the semiconductor chip  20  and optical element  10  are accurately positioned, then the relative positioning of the optical fiber  30  and optical element  10  can be carried out. That is to say, simply by inserting the optical fiber  30  in the hole  28 , the relative positioning of the optical fiber  30  and optical element  10  can be carried out.  
         [0104]    This embodiment may include a step for preventing the optical fiber  30  from being pulled out. For example, the optical fiber  30  may be passed through the hole  46  in the substrate  42  and inserted in the hole  28  in the semiconductor chip  20 , then the hole  46  in the substrate  42  filled with the filling material  54 . If the filling material  54  is cured, the optical fiber  30  is fixed to the substrate  42 , and therefore the optical fiber  30  can be prevented from being pulled out of the hole  28  in the semiconductor chip  20 .  
         [0105]    This embodiment may include a step of packaging the optical element  10  and semiconductor chip  20 . For example, between the optical element  10  and semiconductor chip  20  is filled with the underfill material  40 . By means of this, the surfaces of the optical element  10  and semiconductor chip  20  are protected, the electrical connection between the two is protected, and the connection state of the two is maintained.  
         [0106]    Furthermore, at least the exposed surface of the optical element  10  and semiconductor chip  20 , the electrical connection between the two, and the electrical connection between at least either of the optical element  10  and semiconductor chip  20  and the interconnect pattern  48  formed on the substrate  42 , are preferably sealed with the resin  56  or the like. By means of the above process, an optical module with the optical element  10  and semiconductor chip  20  packaged can be obtained.  
         [0107]    The present invention is not limited to the above-described embodiment, and various modifications described below are possible.  
         [0108]    Second Embodiment  
         [0109]    [0109]FIG. 3 shows a second embodiment of an optical module to which the present invention is applied. This optical module differs from the first embodiment in the construction of external terminals  60 . That is to say, the external terminals  60  are provided on the surface of a substrate  62 . For example, on one surface of the substrate  62  an interconnect pattern  64  is formed, and the external terminals  60 , electrically connected to the interconnect pattern  64  through through holes  66 , are formed on the other surface of the substrate  62 . The external terminals  60  may be for example solder balls. By means of this, the optical module can be surface mounted. The optical module of this embodiment can also be packaged by a resin  68  or the like.  
         [0110]    In this embodiment, apart from the above-described points, the description of the first embodiment applies, and more detailed explanation is omitted here.  
         [0111]    Third Embodiment  
         [0112]    [0112]FIG. 4 shows a third embodiment of an optical module to which the present invention is applied. This optical module has a lead frame  70 , and the extremities of the lead frame  70  (outer leads) are external terminals  72 .  
         [0113]    The lead frame  70  is adhered to a substrate  74 . When a semiconductor device lead frame  70  is used, the substrate  74  is adhered to die pads  71  of the lead frame  70 . For the adhesion, an adhesive not shown in the drawings can be used. The substrate  74  may be formed of a resin or the like, or may be formed of silicon or glass. On the substrate  74  an interconnect pattern  76  is formed. In particular, when the substrate  74  is formed of silicon, the manufacturing process of the semiconductor device can be applied, and a precision interconnect pattern  76  can be formed.  
         [0114]    In this embodiment, an optical element  78  and a semiconductor chip  80  are mounted on the substrate  74 . The optical element  78  and semiconductor chip  80  are bonded by face-down bonding to the interconnect pattern  76  on the substrate  74 . The interconnect pattern  76  is electrically connected to the lead frame  70  by wires  75  or the like. By means of wires  77 , the interconnect pattern  76  and at least either of the optical element  78  and semiconductor chip  80  may be electrically connected.  
         [0115]    An optical fiber  82  is positioned by means of a hole  84  formed in the substrate  74 . The portion of the lead frame  70  which is adhered to the substrate  74  preferably has formed a hole avoiding the optical fiber  82 .  
         [0116]    For other aspects of the construction, the description of the first embodiment applies. The optical module of this embodiment is also packaged by a resin  86  or the like.  
         [0117]    It should be noted that in place of the “semiconductor chip” of the present invention, a chip including an internal circuit not using a semiconductor may also be applied, and in this case the same benefit as the present invention can be obtained.  
         [0118]    Fourth Embodiment  
         [0119]    [0119]FIG. 5 shows an embodiment of an optical transmission device to which the present invention is applied. An optical transmission device  90  is used to mutually connect electronic instruments  92  such as a computer, a display, a memory device, and a printer. The electronic instruments  92  may equally be data communications devices. The optical transmission device  90  may have plugs  96  provided at both ends of a cable  94 . The cable  94  includes one or a plurality of (at least one) optical fiber(s)  30  (see FIG. 1). The plugs  96  incorporate-semiconductor chip  20 . The fixing of the optical fiber  30  to the optical element  10  or the semiconductor chip  20  is as described above.  
         [0120]    The optical element  20  connected to one end of the optical fiber  30  is a light-emitting element. An electrical signal output from one electronic instrument  92  is converted to an optical signal by the optical element  20  being a light-emitting element. The optical signal passes through the optical fiber  30 , and is input to the optical element  20  at the other end. This optical element  20  is an light-receiving element, and converts the input optical signal to an electrical signal. The electrical signal is input to the other electronic instrument  92 . In this way, this embodiment of the optical transmission device  90  enables information to be transferred between the electronic instruments  92  by means of an optical signal.  
         [0121]    Fifth Embodiment  
         [0122]    [0122]FIG. 6 shows the use of an embodiment of an optical transmission device to which the present invention is applied. The optical transmission device  90  connects electronic instruments  100 . As the electronic instruments  100  may be cited liquid crystal display monitors or digital support CRTs (These may be used in the financial, communications marketing, medical, and educational fields.), liquid crystal projectors, plasma display panels (PDP), digital TV, retail cash registers (for Point of Sale Scanning (POS)), video, tuners, games machines, printers, and so on.  
         [0123]    Sixth Embodiment  
         [0124]    [0124]FIG. 7 shows an embodiment of an optical module to which the present invention is applied. This optical module comprises a semiconductor chip  110 , a plurality of optical elements  10 , and a plurality of optical fibers  30 . In the semiconductor chip  110  are formed a plurality of holes  112 , and an optical fiber  30  is inserted into each of the holes  112 . Corresponding to each optical fiber  30 , an optical element  10  is provided. In the example shown in FIG. 7, the optical module has four optical elements  10 , and when these are used to transmit a color image signal, the optical elements  10  and optical fibers  30  are used to transmit red, green, and blue signals and a clock signal.  
         [0125]    For other aspects of the construction, the description of the first embodiment applies. The optical module of this embodiment can also be packaged by a resin or the like.  
         [0126]    Seventh Embodiment  
         [0127]    [0127]FIG. 8 shows an embodiment of an optical module to which the present invention is applied. This optical module has an optical element  210 , a semiconductor chip  220 , and an optical fiber  30 . The optical element  210  is provided with a stopper  214  so that the end of the optical fiber  30  does not contact an optical section  212 . The stopper  214  is provided in a position being the surface of the optical element  210  on which the optical section  212  is provided, corresponding to within the area of the end surface of the optical fiber  30 . By forming the stopper  214  to be higher than the optical section  212 , the end surface of the optical fiber  30  is prevented from contacting the optical section  212 .  
         [0128]    In the semiconductor chip  220 , a hole  222  is formed for the optical fiber  30  to be passed through. The hole  222  is formed with opening extremities and a central part of larger diameter than the opening extremities. The opening extremities and central part are connected by tapers.  
         [0129]    The hole  222  of this shape can be formed as follows. First, a layer patterned to form an opening in the region in which the hole  222  is to be formed is formed on the semiconductor chip  220 . This layer may be of resist, or may be an oxide film, or may be a film formed by applying chemical vapor deposition (CVD). Then the opening in the layer of resist or the like (the surface of the semiconductor chip  220 ) is etched. For the etching it is preferable that dry etching be applied. The dry etching may be reactive ion etching (RIE). As the etching may be applied wet etching. In this way, on the surface of the semiconductor chip  220 , a depression (not a through hole) is formed.  
         [0130]    Then in the portion of the semiconductor chip  220  where the depression is formed, using a laser (for example a YAG laser or CO 2  laser) or the like, a small hole is formed. The laser beam can be directed to recognize the position of the depression. The laser beam may be directed from one side of the semiconductor chip  220 , or the laser beam may be directed from both sides of the semiconductor chip  220  (either sequentially or simultaneously). If the laser beam is directed from both sides, the effect on the semiconductor chip  220  is reduced. It should be noted that when directing the laser beam from both sides, it is preferable for depressions to be formed in both surfaces of the semiconductor chip  220 .  
         [0131]    Next the small hole is enlarged to form the hole  222 . For example, applying wet etching, the internal wall of the small hole may be etched. As etchant may be used, for example, a mixture of hydrofluoric acid and ammonium fluoride in aqueous solution (buffered hydrofluoric acid). Then the layer of resist or the like is removed as required.  
         [0132]    It should be noted that elements may be formed on the semiconductor chip  220  after forming the hole  222 , but if the presence of the hole  222  makes the formation of elements difficult, elements may be formed first.  
         [0133]    For other aspects of the construction, the description of the first embodiment applies. The optical module of this embodiment can also be packaged by a resin or the like. It should be noted that the interior of the hole  222  is preferably filled with the filling material  54  fixing the optical fiber  30 .  
         [0134]    In the above embodiments, an optical fiber was used as an optical waveguide, but a sheet form or strip form optical waveguide may equally be used. The optical waveguide may be formed of polyimide resin.