Patent Publication Number: US-2022214391-A1

Title: Connecting device for inspection

Description:
TECHNICAL FIELD 
     The present invention relates to a connecting device for inspection used for inspecting the characteristics of an inspection object. 
     BACKGROUND ART 
     Semiconductor devices to which electrical signals and optical signals are transmitted (referred to below as “optoelectronic devices”) are formed on silicon substrates or the like by use of silicon photonics. 
     To inspect the characteristics of an optoelectronic device in a wafer state, it is effective to connect the optoelectronic device and an inspecting device by use of a connecting device for inspection including electric contacts that transfer electrical signals and optical contacts that transfer optical signals (refers to Patent Literature 1 and Patent Literature 2). For example, probes formed of conductive material are used as the electric contacts for connecting the optoelectronic device and the inspecting device, and optical fibers are used as the optical contacts for connecting the optoelectronic device and the inspecting device. 
     CITATION LIST 
     Patent Literature 
     
         
         Patent Literature 1: Japanese Unexamined Patent Application Publication No. H07-201945 
         Patent Literature 2: Japanese Unexamined Patent Application Publication No. 2018-81948 
       
    
     SUMMARY OF THE INVENTION 
     Technical Problem 
     The connecting device for inspection including units provided with the electric contacts and units provided with the optical contacts formed independently of each other is typically used for inspecting the optoelectronic device. The positioning between the optoelectronic device and the connecting device for inspection requires a certain period of time to align the optoelectronic device with the respective units independently of each other. In addition, the connecting device for inspection having the configuration described above has a problem of executing a test (a multi-test) that performs an electrical measurement using electrical signals and an optical measurement using optical signals simultaneously. 
     In response to this issue, the present invention provides a connecting device for inspection having a configuration capable of facilitating an alignment with an optoelectronic device and executing an electrical measurement and an optical measurement simultaneously. 
     Solution to Problem 
     An aspect of the present invention provides a connecting device for inspection including a probe head configured to hold an electric contact and an optical contact such that tip ends of the respective contacts are exposed on a lower surface of the probe head while a proximal end of the electric contact is exposed on an upper surface of the probe head and the optical contact is fixed to the probe head, and a transformer including a connecting wire provided therein such that a tip end on one side of the connecting wire electrically connected to the proximal end of the electric contact exposed on the upper surface of the probe head is arranged in a lower surface of the transformer while the optical contact slidably penetrates the transformer. A positional relationship between the tip end of the electric contact and the tip end of the optical contact on the lower surface of the probe head corresponds to a positional relationship between an electrical signal terminal and an optical signal terminal of a semiconductor device, and the optical contact continuously penetrates the probe head and the transformer. 
     Advantageous Effects of the Invention 
     The present invention can provide the connecting device for inspection with the configuration capable of facilitating the alignment with the optoelectronic device and executing the electrical measurement and the optical measurement simultaneously. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG. 1  is a schematic view illustrating a structure of a connecting device for inspection according to an embodiment of the present invention. 
         FIG. 2  is a schematic view illustrating a state in which a probe head and a transformer are attached to the connecting device for inspection according to the embodiment of the present invention. 
         FIG. 3  is a schematic view illustrating a state in which an optical contact is fixed to the probe head in the connecting device for inspection according to the embodiment of the present invention. 
         FIG. 4  is a schematic view illustrating a state in which the probe head and the transformer are separated from each other in the connecting device for inspection according to the embodiment of the present invention. 
         FIG. 5  is a schematic view illustrating an example of a tip end of the optical contact in the connecting device for inspection according to the embodiment of the present invention,  FIG. 5( a )  to  FIG. 5( d )  showing a variation in shape of the tip end of the optical contact. 
         FIG. 6  is a schematic view illustrating another example of the tip end of the optical contact in the connecting device for inspection according to the embodiment of the present invention,  FIG. 6( a )  and  FIG. 6( b )  showing a variation in shape of the tip end of the optical contact. 
         FIG. 7  is a schematic view illustrating still another example of the tip end of the optical contact in the connecting device for inspection according to the embodiment of the present invention,  FIG. 7( a )  and  FIG. 7( b )  showing a variation in shape of the tip end of the optical contact. 
         FIG. 8  is a schematic plan view illustrating a structure of a top guide plate of the probe head in the connecting device for inspection according to the embodiment of the present invention. 
         FIG. 9  is a schematic view for explaining an operation during inspection in the connecting device for inspection according to the embodiment of the present invention (part  1 ). 
         FIG. 10  is a schematic view for explaining the operation during inspection in the connecting device for inspection according to the embodiment of the present invention (part  2 ). 
         FIG. 11  is a schematic view for explaining the operation during inspection in the connecting device for inspection according to the embodiment of the present invention (part  3 ). 
         FIG. 12  is a plan view illustrating an example of a structure of an optoelectronic device as a target to be inspected. 
         FIG. 13  is a plan view illustrating an example of positions of guide holes provided in a bottom guide plate of the probe head in the connecting device for inspection according to the embodiment of the present invention. 
         FIG. 14  is a plan view illustrating the bottom guide plate of the probe head in the connecting device for inspection according to the embodiment of the present invention,  FIG. 14( a )  to  FIG. 14( e )  showing a variation in arrangement of units composing the bottom guide plate. 
     
    
    
     DESCRIPTION OF EMBODIMENTS 
     Some embodiments of the present invention are described below with reference to the drawings. The same or similar elements illustrated in the drawings are denoted below by the same or similar reference numerals. It should be understood that the drawings are illustrated schematically, and the proportions of the thicknesses of the respective elements in the drawings are not drawn to scale. It should also be understood that the dimensional relationships or proportions between the respective drawings can differ from each other. The embodiments described below illustrate devices or methods for embodying the technical idea of the present invention, but the respective embodiments are not intended to be limited to the materials, shapes, structures, or arrangements of the constituent elements as described herein. 
     A connecting device for inspection according to an embodiment of the present invention illustrated in  FIG. 1  is used for inspecting an optoelectronic device including an electrical signal terminal to which an electrical signal is transmitted and an optical signal terminal to which an optical signal is transmitted. The optoelectronic device as used herein can be presumed to be, but not necessarily, a semiconductor device such as a silicon photonic device and a vertical cavity surface emitting laser (VCSEL). The optoelectronic device as a target to be inspected, not illustrated in  FIG. 1 , has a configuration in which a surface provided with the optical signal terminal and the electrical signal terminal (also collectively referred to below as “signal terminals”) is opposed to the connecting device for inspection. 
     The connecting device for inspection illustrated in  FIG. 1  includes electric contacts  10 , optical contacts  20 , a probe head  30  holding the electric contacts  10  and the optical contacts  20  such that the respective tip ends are exposed on the lower surface of the probe head  30 , and a transformer  40  arranged on the probe head  30 . The tip ends of the electric contacts  10  extend downward from the lower surface of the probe head  30 , while the proximal ends of the electric contacts  10  are exposed on the upper surface of the probe head  30 . The optical contacts  20  extend upward from the upper surface of the probe head  30 . 
     A relative positional relationship between the tip end of the respective electric contacts  10  and the tip end of the respective optical contacts  20  as viewed in a surface normal direction of the lower surface of the probe head  30  (referred to below as a “planar view”) corresponds to a relative positional relationship between the electrical signal terminal and the optical signal terminal of the optoelectronic device as a target to be inspected. In particular, the respective electric contacts  10  and the respective optical contacts  20  are held by the probe head  30  with a predetermined positioning accuracy so as to be reliably connected to the respective signal terminals of the optoelectronic device as a target to be inspected during the inspection. The phrase “reliably connected” as used herein refers to a state in which the respective electric contacts  10  and the respective optical contacts  20  are connected to the signal terminals of the optoelectronic device so as to ensure a predetermined measurement accuracy. 
     The tip end of the respective electric contacts  10  is electrically connected to the electrical signal terminal of the optoelectronic device as a target to be inspected. The tip end of the respective optical contacts  20  is optically connected to the optical signal terminal of the optoelectronic device as a target to be inspected. The optical connection leads the optical signal to be transmitted between the optical signal terminal of the optoelectronic device and the respective optical contacts  20 . The optical contacts  20  are fixed to the probe head  30 . 
     The transformer  40  is equipped therein with connecting wires  41 . The tip ends on one side of the connecting wires  41  arranged in the lower surface of the transformer  40  are electrically connected to the proximal ends of the electric contacts  10  exposed on the upper surface of the probe head  30 . The other tip ends of the connecting wires  41  are arranged in the upper surface of the transformer  40 . The optical contacts  20  slidably penetrate the transformer  40 . The optical contacts  20  continuously penetrate the probe head  30  and the transformer  40 . 
     The connecting device for inspection illustrated in  FIG. 1  further includes distributing wires  70  coupled with the other tip ends of the connecting wires  41  arranged inside the transformer  40 , and a main substrate  60  provided thereon with electric terminals  61  electrically connected to the connecting wires  41  via the distributing wires  70 . The distributing wire  70  are connected to the electric terminals  61  by soldering, for example. The main substrate  60  is also provided thereon with an optical terminal  62  coupled with the proximal ends of the optical contacts  20 . 
     The main substrate  60  is provided with an electric circuit (not illustrated) electrically connected to the distributing wires  70  via the electric terminals  61 . A preferable example of the main substrate  60  to be used is a printed substrate (a PCB). An inspecting device (not illustrated) is electrically connected to the electrical signal terminal of the optoelectronic device as a target to be inspected via the main substrate  60 . 
     The inspecting device and the optical contacts  20  are connected to each other via the optical terminal  62  provided on the main substrate  60 . For example, all of the optical contacts  20  may be connected to the inspecting device collectively at a single position of the main substrate  60  by use of an optical connector used as the optical terminal  62 . Alternatively, a plurality of optical terminals  62  connected to the tip ends of the optical contacts  20  may be provided on the main surface of the main substrate  60  so as to connect the inspecting device with the respective optical contacts  20  independently of each other. The optical signals in this case may be input to the inspecting device after being converted to the electrical signals, or may be input directly to the inspecting device, which depends on the specifications of the inspecting device. For example, the optical contacts  20  and the inspecting device may be connected to each other via a photoelectric converting unit mounted on the main substrate  60  so as to use the input/output signals of the inspecting device as the electrical signals. 
     The optical signal terminal and the optical contact  20  are typically optically connected to each other in a state of being adjacent to each other but separately from each other. The connecting device for inspection illustrated in  FIG. 1  enables the optical contacts  20  and the electric contacts  10  to be connected to the optoelectronic device simultaneously during the inspection of the optoelectronic device. 
     Upon the inspection of the optoelectronic device, the tip end of the electric contact  10  is electrically connected to the electrical signal terminal of the optoelectronic device, and the tip end of the optical contact  20  is optically connected to the optical signal terminal of the optoelectronic device. The electrical signal is then input to the optoelectronic device from the tip end of the electric contact  10 , and the optical signal output from the optoelectronic device is input to the tip end of the optical contact  20 , for example, so that the optical signal is detected by the inspecting device. The connecting device for inspection thus functions as a probe card that connects the inspecting device to the optoelectronic device as a target to be inspected. 
     A preferable example of the optical contact  20  to be used is an optical fiber. For example, the optical signal enters, from the optical signal terminal of the optoelectronic device, the end surface of the optical fiber located adjacent to the optical signal terminal. The optical contact  20  is not limited to the optical fiber, and may be any optical member that includes an optical guide. The optical guide of the optical fiber and the like is preferably configured to have a refractive index substantially equal to that of the optoelectronic device. In the case of the application to a silicon photonic device, the optical contact  20  is formed of a material having a refractive index conforming to silicon. 
     A preferable example of the electric contact  10  to be used is a probe formed of a conductive material. The electric contact  10  may be any type of probe. 
     A stiffener  50  having higher strength than the main substrate  60  is fixed to the main substrate  60 . The stiffener  50  is used as a supporting body to ensure mechanical strength of the connecting device for inspection so as to prevent the main substrate  60  from being bent and also fix the respective constituent members to the connecting device for inspection. 
     The stiffener  50  is fixed to the main substrate  60  with fixing bolts  91  in the connecting device for inspection illustrated in  FIG. 1 . The transformer  40  is fixed to the stiffener  50  with fixing bolts  92 . The transformer  40  fixed to the main substrate  60  thus can be presumed to serve as an integrated substrate together with the main substrate  60 . The probe head  30  is attached to the transformer  40  with supporting bolts  93 . 
     Positioning pins  94  are used for aligning the lower surface of the probe head  30  in parallel with the main surface of the optoelectronic device and for adjusting an attachment angle of the probe head  30  with respect to the transformer  40 , for example. The positioning pins  94  are also used for positioning the probe head  30  with the transformer  40  so as to align the positions in the horizontal direction between the tip ends of the distributing wires  70  arranged in the transformer  40  and the upper parts of the electric contacts  10 . 
     As described above, the probe head  30  is attached to the main substrate  60  and the transformer  40  with the supporting bolts  93  and the positioning pins  94 . This structure facilitates the removal and attachment of the probe head  30  with respect to the main substrate  60  and thus facilitates the maintenance of the probe head  30 . 
     As illustrated in  FIG. 2 , the probe head  30  includes a plurality of guide plates arranged separately from each other in the vertical direction between the upper surface and the lower surface through which the electric contacts  10  and the optical contacts  20  each penetrate. The probe head  30  illustrated in  FIG. 2  includes a bottom guide plate  31  located adjacent to the tip ends of the electric contacts  10 , and a top guide plate  32  located adjacent to the proximal ends of the electric contacts  10 . A spacer  33  is interposed between the outer edge region of the bottom guide plate  31  and the outer edge region of the top guide plate  32  so as to provide a hollow region  330  between the top guide plate  32  and the bottom guide plate  31 . The guide plates for supporting the electric contacts  10  and the optical contacts  20  need to have predetermined mechanical strength. In view of this, a ceramic plate is preferably used that has mechanical strength and is easily provided with penetration holes. 
     The probe head  30  further includes a first guide film  34  and a second guide film  35  (also collectively referred to below as “guide films”) arranged between the bottom guide plate  31  and the top guide plate  32 . The electric contacts  10  and the optical contacts  20  penetrate the guide films. The first guide film  34  is arranged adjacent to the bottom guide plate  31 , and the second guide film  35  is arranged substantially in the middle between the bottom guide plate  31  and the top guide plate  32 . The guide films to be used are films made of resin, for example. 
     The electric contacts  10  and the optical contacts  20  penetrate through guide holes provided in the guide plates and the guide films. As illustrated in  FIG. 2 , the position of the top guide plate  32  and the position of the bottom guide plate  31  through which the common electric contacts  10  penetrate are displaced from each other in the planar view (referred to below as an “offset arrangement”). 
     The offset arrangement leads the respective electric contacts  10  to be bent by elastic deformation between the bottom guide plate  31  and the top guide plate  32  inside the hollow region  330 . When each electric contact  10  comes into contact with the optoelectronic device, the electric contact  10  is further bent and buckled so as to be pressed against the optoelectronic device with a predetermined pressure. The offset arrangement thus can bring the electric contact  10  into contact with the optoelectronic device stably. The arrangement of the guide films in the hollow region  330  can prevent the respective electric contacts  10  in a bent state from coming into contact with each other. 
     In the connecting device for inspection according to the embodiment, the optical contacts  20  are fixed to the bottom guide plate  31  that is the lowest guide plate among the plural guide plates included in the probe head  30 . For example, in the state in which the optical contacts  20  penetrate through the guide holes of the bottom guide plate  31 , a resin  80  is injected to the gaps between the guide holes and the optical contacts  20 , as illustrated in  FIG. 3 . The optical contacts  20  are fixed to the bottom guide plate  31  when the resin  80  is cured. 
     The bottom guide plate  31  illustrated in  FIG. 3  is provided with a first guide hole  311  to which the electric contact  10  is inserted, and a second guide hole  312  to which the optical contact  20  is inserted. 
     The first guide hole  311  includes a large-diameter electric guide hole  311   a  having an inner diameter larger than a diameter of the electric contact  10  and a small-diameter electric guide hole  311   b  having an inner diameter substantially the same as the diameter of the electric contact  10 , in which the respective electric guide holes communicate with each other in the extending direction of the first guide hole  311 . The small-diameter electric guide hole  311   b  is located closer to the lower surface of the probe head  30  than the large-diameter electric guide hole  311   a , and the tip end of the electric contact  10  is inserted to the small-diameter electric guide hole  311   b.    
     The tip end of the electric contact  10  is inserted first to the large-diameter electric guide hole  311   a  so that the electric contact  10  is easily inserted to the first guide hole  311 . The electric contact  10  is then inserted to the small-diameter electric guide hole  311   b  communicating with the large-diameter electric guide hole  311   a . Setting the inner diameter of the small-diameter electric guide hole  311   b  to be substantially the same as the diameter of the electric contact  10  enables the accurate positioning of the tip end of the electric contact  10 . The use of the first guide hole  311  including the large-diameter electric guide hole  311   a  and the small-diameter electric guide hole  311   b  communicating with each other contributes to both facilitating the insertion of the electric contact  10  to the guide hole and achieving the accurate positioning of the tip end of the electric contact  10 . 
     The second guide hole  312  includes a large-diameter electric guide hole  312   a  having an inner diameter larger than a diameter of the optical contact  20  and a small-diameter electric guide hole  312   b  having an inner diameter substantially the same as the diameter of the optical contact  20 , in which the respective electric guide holes communicate with each other in the extending direction of the second guide hole  312 . The small-diameter electric guide hole  312   b  is located closer to the lower surface of the probe head  30  than the large-diameter electric guide hole  311   a , and the tip end of the optical contact  20  is inserted to the small-diameter electric guide hole  312   b.    
     The tip end of optical contact  20  is inserted first to the large-diameter electric guide hole  312   a  so that the optical contact  20  is easily inserted to the second guide hole  312 . The optical contact  20  is then inserted to the small-diameter electric guide hole  312   b  communicating with the large-diameter electric guide hole  312   a . The tip end of the optical contact  20  is fixed to the inside of the small-diameter electric guide hole  312   b  with the resin  80 . Setting the inner diameter of the small-diameter electric guide hole  312   b  to be substantially the same as the diameter of the optical contact  20  enables the accurate positioning of the tip end of the optical contact  20 . The use of the second guide hole  312  including the large-diameter electric guide hole  312   a  and the small-diameter electric guide hole  312   b  communicating with each other contributes to both facilitating the insertion of the optical contact  20  to the guide hole and achieving the accurate positioning of the tip end of the optical contact  20 . 
     As described above, the connecting device for inspection according to the embodiment can execute the positioning between the electric contacts  10  and the optical contacts  20  inside the same bottom guide plate  31 , so as to have the advantage of achieving the accurate positioning of the respective tip ends of the electric contacts  10  and the optical contacts  20  quickly. 
     The connecting wires  41  may be part of the distributing wires  70 . In particular, part of the distributing wires  70  is inserted to the penetration holes formed in the transformer  40 , and the tip ends of the distributing wires  70  are exposed on the lower surface of the transformer  40 . The tip ends of the distributing wires  70  and the proximal ends of the electric contacts  10  exposed on the upper surface of the probe head  30  are connected to each other during the attachment of the transformer  40  and the probe head  30 . For example, resin may be inserted to gaps between the penetration holes formed in the transformer  40  and the distributing wires  70  and then cured so as to fix the distributing wires  70  to the transformer  40 . This can fix the positions of the tip ends of the distributing wires  70 . 
     In the connecting device for inspection described above, the probe head  30  and the transformer  40  are detachably attached to each other. In particular, as illustrated in  FIG. 4 , the probe head  30  and the transformer  40  can be separated from each other in the state in which the electric contacts  10  and the optical contacts  20  are positioned. Since the optical contacts  20  are not fixed to the transformer  40 , the optical contacts  20  slide inside the penetration holes formed in the transformer  40  as the probe head  30  is gradually separated from the transformer  40 . 
     The detachable attachment of the probe head  30  and the transformer  40  can ensure the effects of facilitating the maintenance of the connecting device for inspection. For example, a repair or a replacement of the probe head  30  can be executed in the state in which the optical contacts  20  keep penetrating the transformer  40 . This can reduce the time required for the maintenance. The replacement of the electric contacts  10  in the probe head  30  can be executed one by one. The replacement of the optical contacts  20  can be executed together with the bottom guide plate  31  to which the optical contacts  20  are fixed. 
     The proximal ends of the electric contacts  10  exposed on the upper surface of the probe head  30  are led to be electrically connected to the tip ends on one side of the connecting wires  41  arranged in the lower surface of the transformer  40  upon the attachment of the transformer  40  and the probe head  30 . 
     Various kinds of shapes can be used for the tip end of the optical contact  20  opposed to the optoelectronic device. For example, when an optical fiber  21  including a core  211  and a clad  212  is used as the optical contact  20 , the tip end of the optical fiber  21  can have various shapes, as illustrated in  FIG. 5( a )  to  FIG. 5( d ) . 
       FIG. 5( a )  illustrates a straight shape in which the end surface of the optical fiber  21  and the lower surface of the probe head  30  are located on the same plane. The straight shape enables the processing of the probe head  30  most easily. 
       FIG. 5( b )  illustrates a flanged shape in which the opening of the guide hole formed on the lower surface of the probe head  30  has a smaller diameter than the end surface of the optical fiber  21 . The flanged shape leads the tip end of the optical fiber  21  to come into contact with the flange of the guide hole, so as to stably keep the position of the end surface of the optical fiber  21 . 
       FIG. 5( c )  and  FIG. 5( d )  each illustrate a shape in which the end surface of the optical fiber  21  is curved.  FIG. 5( c )  illustrates a case in which the opening of the guide hole formed on the lower surface of the probe head  30  has a tapered shape, and  FIG. 5( d )  illustrates a case in which the opening of the guide hole formed on the lower surface of the probe head  30  has a spherical surface. The curved end surface of the optical fiber  21  facilitates the concentration of light emitted from the optoelectronic device on the optical fiber  21 . 
     As illustrated in  FIG. 6( a )  and  FIG. 6( b ) , the tip end of the optical fiber covered with a coating film  25  may be set to be located below the lower surface of the probe head  30 .  FIG. 6( a )  illustrates a case in which the guide hole through which the optical fiber  21  having a straight-shaped tip end penetrates has a flanged shape in which the lower part is narrowed. This shape leads the coating film  25  provided along the circumference of the optical fiber  21  to come into contact with the flange of the guide hole, so as to stably keep the position of the optical fiber  21 .  FIG. 6( b )  illustrates a case in which the optical fiber  21  having a curved tip end is covered with the coating film  25 . The coating film  25  in this case also comes into contact with the flange of the guide hole. The coating film  25  thus serves as a stopper so as to prevent the optical fiber  21  from coming off the guide hole. The coating film  25  to be used is a resin film, for example. The use of the coating film  25  as a stopper for stopping the optical fiber  21  in the probe head  30  as described above can eliminate the use of resin for fixing the optical fiber  21  to the probe head  30 . The coating film  25  leads the optical fiber  21  to be tightly attached to the probe head  30 . 
     As illustrated in  FIG. 7( a )  and  FIG. 7( b ) , the tip end of the optical fiber  21  not covered with the coating film  25  may be set to be located below the lower surface of the probe head  30 . The optical fiber  21  not covered with the coating film  25  has a smaller outer diameter, contributing to a reduction in pitch, as compared with the optical fiber  21  covered with the coating film  25 . 
     In the case in which the tip end of the optical fiber  21  does not protrude below the lower surface of the probe head  30 , the probe head  30  has a probability of coming into contact with the optoelectronic device when the tip end of the optical fiber  21  is brought closer to the optoelectronic device. The tip end of the optical fiber  21  that protrudes below the probe head  30 , as illustrated in  FIG. 6( a )  and  FIG. 6( b )  or  FIG. 7( a )  and  FIG. 7( b ) , can be brought closer to the optoelectronic device that is still separated from the probe head  30 . 
     The tip end of the optical fiber  21  may be provided with a lens. The fixing method by use of the resin  80  is selected as appropriate depending on the specifications of the tip end of the optical fiber  21 . The lower surface of the probe head  30  can be subjected to grinding processing before the respective electric contacts  10  are inserted to the probe head  30  after the step of fixing the optical fibers  21  to the probe head  30 . 
     As illustrated in  FIG. 8 , the respective guide holes  320  provided in the top guide plate  32  through which the optical contacts  20  penetrate may be used in common with the plural optical contacts  20  adjacent to each other.  FIG. 8  is a plan view illustrating the main surface of the top guide plate  32 . 
     The connecting device for inspection according to the embodiment is used for inspecting the optoelectronic device as follows. The respective electric contacts  10  and the optoelectronic device are positioned with each other with the connecting device for inspection having a configuration in which the tip end of the electric contact  10  extends by a tip-end length T1 below the lower surface of the probe head  30 , as illustrated in  FIG. 9 . The tip-end length T1 is about 200 μm, for example. 
     The positioning is executed such that a stage having a mount surface on which the optoelectronic device is mounted is moved in a direction parallel to the mount surface or is rotated about a central axis in a surface normal direction of the mount surface. This positioning may be executed while an alignment mark provided in the connecting device for inspection is captured by an imaging device such as a CCD camera mounted on the stage. 
     For example, when a captured image of the alignment mark provided in the connecting device for inspection is obtained by the imaging device mounted on the stage, the information on the relative position between the stage on which the optoelectronic device is mounted and the connecting device for inspection is acquired through image processing executed for the captured image. The position and the direction of the stage, for example, are adjusted in accordance with the information on the relative position so that the tip end of the electric contact  10  can be located at a position in contact with the electrical signal terminal of the optoelectronic device. 
     The tip end of the electric contact  10  is then brought into contact with the electrical signal terminal (not illustrated) of the optoelectronic device  100 , as illustrated in  FIG. 10 , in a state in which the tip end of the electric contact  10  and the position of the electrical signal terminal of the optoelectronic device  100  conform to each other in the planar view. Since the positional relationship between the tip end of the electric contact  10  and the tip end of the optical contact  20  corresponds to the positional relationship between the electrical signal terminal and the optical signal terminal of the optoelectronic device  100 , the optical contact  20  is also positioned so as to conform to the optical signal terminal of the optoelectronic device  100 . 
     Next, as illustrated in  FIG. 11 , the optoelectronic device  100  and the connecting device for inspection are brought closer to each other so that the electric contact  10  is pressed at a predetermined pressure against the electrical signal terminal of the optoelectronic device  100 . For example, overdrive is applied so as to press the tip end of the electric contact  10  against the optoelectronic device  100 . 
     The optoelectronic device  100  and the connecting device for inspection are brought closer to each other such that a gap T2 between the tip end of the optical contact  20  and the optical signal terminal of the optoelectronic device  100  reaches a gap that allows the optical contact  20  and the optical signal terminal to be optically connected to each other. The gap between the tip end of the optical contact  20  and the optoelectronic device  100  can be regulated in a predetermined range depending on the setting of the tip-end length T1 of the electric contact  10  and the setting of the overdrive. For example, the gap T2 is about 100 μm when the tip-end length T1 of the electric contact  10  is set to 160 μm and the overdrive of 60 μm is applied. 
     In the connecting device for inspection illustrated in  FIG. 1 , the electric contacts  10  and the optical contacts  20  are each arranged in the probe head  30  with a predetermined positioning accuracy. As described above, the positioning of the electric contact  10  with the electrical signal terminal of the optoelectronic device  100  enables the simultaneous positioning of the optical contact  20  with the optical signal terminal of the optoelectronic device  100 . This facilitates the alignment between the connecting device for inspection and the optoelectronic device  100 . The simultaneous positioning with the predetermined positioning accuracy between the electric contact  10  and the electrical signal terminal of the optoelectronic device  100  and between the optical contact  20  and the optical signal terminal of the optoelectronic device  100  can execute the electrical measurement and the optical measurement for the optoelectronic device  100  simultaneously. 
     The connecting device for inspection to be aligned with the optoelectronic device  100  provided with the electrical signal terminal  101  and the optical signal terminal  102  as illustrated in  FIG. 12  is described below.  FIG. 12  illustrates the optoelectronic device  100  with a VCSEL in which the electrical signal terminal  101  is a signal input terminal, and the optical signal terminal  102  is a light-emission surface. 
     The plural optoelectronic devices  10  are arranged in a wafer. As illustrated in  FIG. 13 , the probe head  30  is prepared that includes a plurality of units  310  each arranged such that a guide hole  301  for electric contact and a guide hole  302  for optical contact respectively correspond to the position of the electrical signal terminal  101  and the position of the optical signal terminal  102 .  FIG. 13  is a plan view illustrating the bottom guide plate  31 . The single unit  310  corresponds to the single optoelectronic device  100 . The probe head  30  thus has a configuration in which the plural units  310  are each arranged such that the tip end of the electric contact  10  and the tip end of the optical contact  20  respectively correspond to the electrical signal terminal and the optical signal terminal of each optoelectronic device  100 . 
     The electric contacts  10  and the optical contacts  20  are inserted to the guide holes provided in the guide plates and the guide films of the probe head  30 . This fixes the positions of the respective tip ends of the electric contacts  10  and the optical contacts  20 . 
     The plural optoelectronic devices  100  are typically arranged in a grid state in the wafer. The units  310  are thus typically positioned to correspond to the positions of the optoelectronic devices  100  arranged in the grid state. The positions of the units  310  may be varied depending on the arrangement of the optoelectronic devices  100  in the wafer.  FIG. 14( a )  to  FIG. 14( e )  illustrate a variation in the arrangement of the units  310 . 
     For example, the units  310  are arranged adjacent to each other both in an X direction and a Y direction, as illustrated in  FIG. 14( a ) . The unit  310  may be arranged adjacent to each other only in the X direction but arranged with intervals interposed therebetween in the Y direction, as illustrated in  FIG. 14( b ) . The units  310  may be arranged with intervals interposed therebetween in the X direction and arranged adjacent to each other in the Y direction, as illustrated in  FIG. 14( c ) . 
     The units  310  may also be arranged with intervals interposed therebetween both in the X direction and the Y direction, as illustrated in  FIG. 14( d ) , or may be arranged diagonally in the planar view, as illustrated in  FIG. 14( e ) . 
     As described above, the connecting device for inspection according to the embodiment includes the electric contacts  10  and the optical contacts  20  positioned in the probe head  30  with a predetermined positioning accuracy so as to ensure the reliable connection of the respective tip ends. The accurate correspondence of the positional relationship between the electric contacts  10  and the optical contacts  20  to the positional relationship between the respective signal terminals of the optoelectronic devices enables the positioning of the electrical signal terminals of the optoelectronic devices with the electric contacts  10 , so as to achieve the accurate positioning of the optical contacts  20  with the optical signal terminals of the optoelectronic devices accordingly. The configuration of the connecting device for inspection thus facilitates the alignment with the optoelectronic devices. In addition, the provision of the electric contact  10  and the optical contact  20  in the same unit  310  enables the electrical measurement and the optical measurement for the optoelectronic device simultaneously. 
     In the connecting device for inspection, the optical contacts  20  penetrate the probe head  30  and the transformer  40  while being fixed to the probe head  30  but not fixed to the transformer  40 . The proximal ends of the electric contacts  10  exposed on the upper surface of the probe head  30  are electrically connected to the tip ends of the connecting wires  41  provided in the lower surface of the transformer  40 . This configuration enables the detachable arrangement between the probe head  30  and the transformer  40 , and facilitates the maintenance of the connecting device for inspection accordingly. 
     Other Embodiments 
     While the present invention has been described above with reference to the embodiment, it should be understood that the present invention is not intended to be limited to the descriptions and the drawings composing part of this disclosure. Various alternative embodiments, examples, and technical applications will be apparent to those skilled in the art according to this disclosure. 
     While the embodiment has been illustrated above with the case in which the connecting wires  41  provided inside the transformer  40  are part of the distributing wires  70 , the transformer  40  used may be a multi-layer wiring substrate such as a multi-layer organic (MLO) substrate or a multi-layer ceramic (MLC) substrate. The use of the wiring substrate as the transformer  40  that uses the connecting wires  41  as a conductive layer can expand the intervals between the respective tip ends on one side of the connecting wires  41  connected to the distributing wires  70  more than the intervals between the respective tip ends on the other side of the connecting wires  41  connected to the proximal ends of the electric contacts  10 . This facilitates the expansion of the intervals between the respective distributing wires  70 . The wiring substrate, when used as the transformer  40 , is provided with the penetration holes through which the optical contacts  20  penetrate in a region in which the connecting wires  41  are not arranged. 
     The electric contacts  10  used may be spring pins instead of the probes bent inside the probe head  30 . 
     It should be understood that the present invention includes various embodiments not disclosed herein.