Abstract:
A mounting apparatus that does not compromise the strength of a probe board. The apparatus comprises a probe board spaced from a support member by a spacer. A fixed portion with a female screw hole is mounted on one surface of the probe board. A male screw member is threaded into the screw hole for the purpose of tightening the support member to the probe board at a fixed distance defined by the length of the spacer. The probe board has a support plate. Pluralities of conductive paths penetrate the support plate. A wiring plate wherein wiring paths are connected to corresponding conductive paths, and whose one surface is fixed to the support plate. The other surface is provided with probes corresponding to the wiring paths. The fixed portion includes a female screw member at an area where no conductive paths are formed.

Description:
RELATED APPLICATIONS 
   This application claims the benefit of Japanese Patent Application No. 2007-54259, filed Mar. 5, 2007. 
   BACKGROUND OF THE INVENTION 
   The present invention relates to an electrical connecting apparatus such as a probe card to be used for an electrical test of an electrical circuit to connect, for example, an integrated circuit as a device under test to a tester that performs an electrical test of it. 
   As one of the conventional electrical connecting apparatuses of this kind is proposed an electrical connecting apparatus comprising a probe board provided with a plurality of probes and enabling adjustment of the planarity of the probe board Japanese Unexamined Patent Publication No. 2003-528459). With this electrical connecting apparatus, a thrusting force or a tensile force can act from a support member supporting the probe board toward a part of the probe board. Adjustment of this acting force can correct bend and deformation of the probe board even if the probe board is bent to maintain the planarity of the probe board. 
   Accordingly, since the planarity of the probe board can be maintained by the aforementioned adjustment work after the probe board has been attached to the support member even if the probe board is bent and deformed at the time of manufacture of the probe board provided with the plurality of probes, the tips of the plurality of probes extending from the probe board can be held on the same plane. Thus, since the tips of all the probes can reliably contact electrical connecting terminals, corresponding to the respective probes, of an electrical circuit as a device under test, efficient electrical contact can be attained between them. 
   However, in the aforementioned prior art described in Japanese Unexamined Patent Publication No. 2003-528459, adjustment is needed every time of the probe board is attached to the support member in accordance with bend and deformation introduced in each probe board so that all the probe tips may be located on the same plane. The adjustment work to let all the probe tips appropriately contact the aforementioned corresponding respective electrical connecting terminals of the device under test in a state where the probe board is attached to the support member is troublesome and requires skills. Especially, in a test of numerous integrated circuits formed on a semiconductor wafer, the number of probes to be provided on the probe board significantly increases. Thus, the adjustment work to let such numerous probes appropriately contact the corresponding respective pads on the semiconductor wafer is not easy. 
   Under such circumstances, the present applicant proposed in a prior International Patent Application (PCT/JP2005/009812) an electrical connecting apparatus that requires no planarity adjustment work of the probe board after being attached to the support member regardless of the deformation of the probe board and enables reliable electrical connection between the probes and the corresponding electrical connecting terminals of the electrical circuit as a device under test. 
   In this electrical connecting apparatus, a spacer allowing an attachment bolt to pass therethrough is arranged between the attachment surface of the support member and the probe board so that the tips of the probes provided on the probe board are aligned on the same surface. The tip of this attachment bolt is screwed in a screw hole in a fixed portion formed on an opposite surface of a surface of the probe board on which the probes are provided. The aforementioned spacer acts to keep predetermined space between the attachment surface of the support member and the probe board so that the probe tips are located on the same surface at the time of tightening of the attachment bolt. 
   Thus, after the probe board is attached to the support member, the tips of all the probes can be thrust to the respective electrical connecting terminals of the electrical circuit as a device under test approximately uniformly without the need for the conventional adjustment work for planarization of the probe board. As a result, the aforementioned conventional troublesome planarity adjustment work is not needed per replacement of the probe board provided with the plurality of probes, which enables an efficient electrical test. 
   Meanwhile, such a probe board is formed by combining a wiring plate in which wiring paths are formed in a multilayered form and to which the probes are provided per corresponding wiring path with a support plate such as a ceramic plate supporting the wiring plate at the opposite surface of the surface to which the probes are provided. Numerous conductive paths referred to as through holes are formed to pass through the ceramic plate as the support plate of the probe board in the plate thickness direction for electrical paths for the corresponding probes. Also, on the ceramic plate is formed the fixed portion in which the tip of the aforementioned attachment bolt is screwed. 
   This fixed portion is formed by fixing a female screw member at an area where unnecessary ones out of the through holes or conductive paths formed in the ceramic plate are provided. Accordingly, when a strong tensile force acts on the female screw member forming the fixed portion at the time of and as a result of tightening of the aforementioned attachment bolt, a portion of the ceramic plate fixed by the female screw member is tensed by the female screw member. Since the rim portion of the through hole under the female screw member of the ceramic plate can be a fragile portion of the probe board against this tensile force, heightening of the mechanical strength of the probe board has been desired. 
   BRIEF SUMMARY OF THE INVENTION 
   It is an object of the present invention to provide an electrical connecting apparatus that does not cause lack of mechanical strength in the support plate of the probe board. 
   The present invention focuses attention on the fact that numerous unused conductive paths exist in the support plate of the probe board such as the ceramic plate and is characterized by forming in this support plate an area where no conductive paths are arranged and forming at this area where no conductive paths are arranged a fixed portion in which a male screw member is screwed. 
   More specifically, an electrical connecting apparatus according to the present invention comprises a support member, a flat plate shaped probe board spaced from one surface of the support member, arranged with its one surface opposed to the support member, and provided on its other surface with numerous probes that are connected to a tester and whose tips can abut on electrode terminals of a device under test for an electrical test by the tester, a fixed portion formed on one surface of the probe board and provided with an opened screw hole at its top portion, a cylindrical spacer keeping a distance from the support member to a top surface of the fixed portion, and a male screw member that penetrates the support member and whose tip is screwed in the screw hole of the fixed portion for the purpose of tightening the support member and the probe board at a distance in accordance with the length of the spacer. The probe board has a support plate in which a plurality of conductive paths penetrating in the plate thickness direction and connected to the tester are formed and a wiring plate in which wiring paths are formed, whose one surface is fixed to the support plate so as to let the wiring paths connected to the corresponding conductive paths, and on the other surface of which are provided the probes corresponding to the wiring paths, and on one surface of the support plate is fixed a female screw member to form the fixed portion. This female screw member is characterized by being fixed to the support plate at an area of the support plate where no conductive paths are formed. 
   In the electrical connecting apparatus according to the present invention, the female screw member is fixed to the support plate at a solid area where no conductive paths such as through holes are formed. Thus, the rim portion of the through hole housing the conductive path of the support plate will not be fixed to the female screw member. Accordingly, even when tightening by the male screw member acts on the female screw member, this tightening force will not act on the rim portion of the through hole housing the conductive path of the support plate. Thus, since no strong tensile force will act on the rim portion of the through hole, which is a fragile portion against the aforementioned tightening force, via the female screw member, it is possible to prevent breakages from occurring on the support plate as a result of this tensile force. Consequently, the mechanical strength of the support plate is heightened 
   The female screw member may be a metal nut. In such a case, the female screw member may be fixed to the support plate via a metal film. As this metal film, a part of a wiring layer formed in the support plate may be utilized. On this metal film utilizing the wiring layer, the female screw member that is the metal nut may be fixed firmly by brazing or by using adhesive. 
   The support plate may be constituted by a ceramic plate. Also, another electrical insulating plate having approximately the same Young&#39;s modulus as that of this ceramic plate may be used as the support plate. 
   As the spacer, a spacer having a head portion whose lower surface is mounted on the other surface of the support member and a body portion whose one edge is connected to the head portion, that is arranged to pass through a through hole formed in the support member, and whose other edge is arranged to abut on the top surface of the fixed portion may be used. The spacer may be given a length dimension required to align the height locations of tips of the probes on the same virtual surface by collaborating with the fixed portion. 
   It is preferable that the spacer is prevented from moving in the axial direction of the body portion in relation to the support member by releasable lock means. Instead of this lock means, the spacer may be screwed in the support member. 
   As the spacer, a spacer whose distance from the lower surface of the head portion to the other edge of the body portion is applicable to maintain the tips of the probes on the same virtual plane may be selected and used in accordance with variation within process tolerance of the top surface of the fixed portion. 
   Between the support member and the probe board, a wiring board having a wiring path to be connected to the tester and having a through hole that allows the spacer to pass therethrough may be arranged. Also, between the wiring board and the probe board, a connector having a through hole that allows the spacer to pass therethrough and connecting the wiring path of the wiring board to the corresponding conductive path of the support plate may be arranged. In such a case, the spacer may be arranged to pass through the respective through holes of the wiring board and the connector. Also, the male screw member is applied so that its tip may be screwed in the screw hole of the fixed portion of the probe board. 
   As the connector, a pogo pin connector having a pogo pin contactor as a contactor may be used. 
   According to the present invention, since there are no conductive paths such as through holes directly under the fixed portion formed on the support plate, but the solid portion of the support plate is located there, the mechanical strength of a portion of the probe board supporting the fixed portion can be heightened. Thus, even when the conventional strong tightening force acts on the fixed portion by the male screw member screwed in the fixed portion, it is possible to prevent damage such as breakages from occurring at the portion of the probe board supporting the fixed portion by this tightening force, which can improve durability of the electrical connecting apparatus. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a plan view showing an electrical connecting apparatus according to the present invention. 
       FIG. 2  is a cross-sectional view obtained along the line II-II shown in  FIG. 1 . 
       FIG. 3  is an enlarged cross-sectional view showing the probe board shown in  FIG. 2 . 
       FIG. 4  is a plan view of the probe board shown in  FIG. 3 . 
   

   DETAILED DESCRIPTION OF THE INVENTION 
   An electrical connecting apparatus  10  according to the present invention is shown in  FIGS. 1 and 2 . This electrical connecting apparatus  10  is used in an electrical test of a semiconductor wafer  14  on a conventionally well-known vacuum chuck  12  constituting a stage of a tester as shown in  FIG. 2 , for example. In the semiconductor wafer  14  are integrated not shown numerous IC circuits, and for an electrical test of these IC circuits, the electrical connecting apparatus  10  is used to connect the respective connection pads of the respective IC circuits to an electrical circuit of a tester main body (not shown). 
   The electrical connecting apparatus  10  is used, being attached to a tester head of the aforementioned tester, for example. The electrical connecting apparatus  10  comprises a circular flat plate shaped wiring board  18  whose rim portion is held at an annular card holder  16  provided to the aforementioned tester head, a circular flat plate shaped support member  20  attached to an upper surface  18   a  of the wiring board, a probe board  22  arranged to be spaced from a lower surface  18   b  of the wiring board  18 , and an electrical connector  24  arranged between the lower surface  18   b  of the wiring board  18  and an upper surface  22   a  of the probe board facing the lower surface, as shown in  FIG. 2 . 
   On a lower surface  22   b  of the probe board  22  are provided numerous probes  26 . Each probe  26  corresponds to aforementioned each connection pad provided in the aforementioned IC circuit on the semiconductor wafer  14 . As this probe  26 , various kinds of conventional well-known probes such as a needle type, a blade type, or a pogo pin type instead of a cantilever type shown in the figure may be used. 
   The support member  20 , wiring board  18 , electrical connector  24 , and probe board  22  are combined integrally by male screw members  28  such as bolts with tips  26   a  of the probes  26  provided on the probe board directing downward. For this combination, each male screw member  28  is arranged to extend through the support member  20 , wiring board  18 , and electrical connector  24  from an upper surface  20   a  side of the support member  20 , and its tip is screwed in a fixed portion  30  formed on the upper surface  22   a  of the probe board  22 . This fixed portion  30  is formed by a female screw member  30  as described later. 
   The male screw member  28  is equipped with a cylindrical spacer  32  whose tip abuts on the top surface of the fixed portion  30 . The spacer  32  has a head portion  32   a  and a body portion  32   b  whose one edge is connected to the head portion, and a through hole  32   c  penetrating the head portion  32   a  and the body portion  32   b  and allowing the male screw member  28  to pass therethrough is formed. The spacer  32  is arranged to pass through respective through holes  20   c  and  18   c  provided in the support member  20  and the wiring board  18 , and the spacer  32  located at the center is arranged to pass through a through hole  24   c  of the electrical connector  24  as well. 
   In the example shown in  FIG. 2 , on the upper surface  20   a  of the support member  20  is formed a recess  34  to receive the head portion  32   a , and the lower surface of the head portion  32   a  is mounted on a bottom surface  34   a  of the recess  34  so that the upper surface of the head portion  32   a  may correspond to the upper surface  20   a  in the recess. The other edge or lower edge of the body portion  32   b  of the spacer  32  abuts on the top surface of the fixed portion  30 . Also, the upper surface of the head portion  32   a  abuts on the inner rim portion of an annular lock tool  38 , for example, removably fixed on the upper surface  20   a  with male screw members  36  screwed in the support member  20  as shown in  FIG. 2  although the male screw members  36  are omitted in  FIG. 1  for simplification of the drawing. This prevents the spacer  32  from moving in its axial direction in relation to the support member  20 . 
   The spacer  32  having a length dimension required to align the respective tips  26   a  of the probes  26  on a virtual plane P 1  parallel to the lower surface  20   b  of the support member  20  as a reference plane when the tip of the male screw member  28  inserted in each spacer  32  is screwed in the fixed portion  30 , and the male screw member  28  is tightened, is selected in accordance with the applicable position in each case. More specifically, the spacer  32  whose distance from the lower surface of the head portion  32   a  of the spacer  32  to the lower edge of the body portion  32   b  is applicable to maintain the tips  26   a  of the probes  26  on the same virtual plane P 1  is selected and used in accordance with bend of the probe board  22  or variation such as process tolerance of the top surface of the fixed portion  30 . 
   The wiring board  18  is a printed circuit board (PCB) similar to a conventional wiring board, and as shown in  FIG. 1 , the annular rim portion of its upper surface  18   a  is exposed from the outer rim of the support member  20  arranged concentrically with the wiring board  18 . At this exposed rim portion, a plurality of sockets  40  constituting connectors to the aforementioned tester are arranged annularly. 
   Referring to  FIG. 2  again, in the wiring board  18  are formed a plurality of wiring paths  42  corresponding to the respective sockets  40 . In  FIG. 2 , one of them is shown representatively and schematically. Each wiring path  42  extends from the upper surface  18   a  to the lower surface  18   b  of the wiring board  18  and is connected to the corresponding socket  40  at its upper surface  18   a . Also, the wiring path  42  is connected to the corresponding probe  26  of the probe board  22  via the electrical connector  24  at the lower surface  18   b.    
   The electrical connector  24  disposed between the wiring board  18  and the probe board  22  is a well-known pogo pin connector in the example shown in  FIG. 2 . This pogo pin connector  24  comprises a pogo pin block  24   a  inserted between the wiring board  18  and the probe board  22  and a plurality of pogo pins  24   b  embedded in the pogo pin block. The aforementioned through hole  24   c  of the electrical connector  24  receiving the spacer  32  is formed in the pogo pin block  24   a  in the plate thickness direction. Each pogo pin  24   b  of the electrical connector  24  electrically connects the wiring path  42  provided in the wiring board  18  with a wiring path  44  provided in the probe board  22  corresponding to it. 
   To each wiring path  44  is connected each corresponding probe  26 . Thus, since each probe  26  of the probe board  22  is connected to the socket  40  via the wiring path  44  of the probe board  22 , the pogo pin  24   b  of the electrical connector  24 , and the wiring path  42  of the wiring board  18 , it is connected to the electrical circuit of the tester main body via an electrical wire connected to the socket. Accordingly, by letting the tip  26   a  of each probe  26  contact aforementioned each corresponding connection pad of the semiconductor wafer  14 , the electrical test of the aforementioned IC circuit integrated in the semiconductor wafer  14  can be performed. 
     FIG. 3  is a cross-sectional view showing a specific example of the probe board  22 . In the example shown in  FIG. 3 , the probe board  22  has a support plate  46  such as a ceramic plate, for example, having an upper surface  46   a  opposed to the lower surface  18   b  of the wiring board  18  and a wiring plate  48  such as a resilient multilayered wiring board, for example, fixed to a lower surface  46   b  of the support plate. 
   The support plate  46  has an approximately uniform thickness dimension, and numerous conductive paths  44   a  are formed in the plate thickness direction. This conductive path  44   a  is formed by a hollow through hole having a conductive layer made of a metal layer, for example, formed by covering the peripheral wall of a through hole formed in the plate thickness direction of the support plate  46  or a solid through hole made of a conductive member filling the aforementioned through hole, as is conventionally well known although not shown in the figure. The conductive path  44   a  is connected to the lower edge of the corresponding pogo pin  24   b  of the electrical connector  24  at the upper surface  46   a  of the support plate  46 . 
   Since the through holes are formed in the support plate  46  regardless of whether this conductive path  44   a  is the aforementioned hollow through hole or the solid through hole, this lowers the strength of the support plate. Thus, in the present invention, the through holes or conductive paths  44   a  are arranged to be distributed approximately evenly at an area except the arrangement area of the female screw members  30  forming the fixed portions  30 , as shown in  FIGS. 3 and 4 . In  FIG. 4 , the circular areas shown as a numeral  50  represent locations of the fixed portions  30  or female screw members  30 , and in the flat surface area (upper surface  46   a ,  46   b ) except these circular areas  50  are formed the numerous through holes  44   a  to be distributed evenly and to penetrate the support plate  46  in the plate thickness direction. 
   The female screw member  30  is a metal nut, for example, and is fixed with adhesive, for example, at the circular area  50  where no through holes  44   a  are formed on the upper surface  46   a  of the support plate  46  so that the tip of the male screw member  28  may be screwed in a not shown screw hole. Instead of the adhesive, the metal nut  30  may be fixed on the upper surface  46   a  by brazing. In such a case, a metal layer is formed at the circular area  50  in relation to formation of the conductive paths  44   a , and the metal nut  30  is brazed at the metal layer. 
   As for the wiring plate  48 , its upper surface  48   a  is fixed to the lower surface  46   b  of the support plate  46 . On a lower surface  48   b  of the wiring plate  48  are fixed the aforementioned probes  26 . Also, in the wiring plate  48  are formed wiring paths  44   b  corresponding to the probes  26 . Thus, the conductive path  44   a  or through hole  44   a  of the support plate  46  and the wiring path  44   b  of the wiring plate  48  collaborate with each other to constitute the wiring path  44  of the probe board  22  extending from the upper surface  22   a  of the probe board  22  (upper surface  46   a  of the support plate  46 ) to the lower surface  22   b  of the probe board  22  (lower surface  48   b  of the wiring plate  48 ). 
   In the electrical connecting apparatus  10  according to the present invention, the probe board  22  is constituted by the support plate  46  in which the conductive paths  44   a  or through holes  44   a  are formed and the wiring plate  48  whose upper surface  48   a  is fixed to the support plate  46 , whose lower surface  48   b  is provided with the probes  26 , and in which the wiring paths  44   b  each forming the wiring path  44  to the probe  26  together with the through hole  44   a  are provided. While the through holes  44   a  are formed in the support plate  46 , the female screw members  30  forming the fixed portions  30  are fixed to the probe board  22  at the circular areas  50  where no through holes  44   a  are formed, as described above. 
   Accordingly, even when tightening by the male screw member  28  acts on the female screw member  30 , this tightening force will not act on the rim portion of the through hole  44   a  of the support plate  46  since no through holes  44   a  are formed under the female screw member. Thus, since no strong tensile force will act on the rim portion of the through hole  44   a , which is a fragile portion against the aforementioned tightening force, via the female screw member  30 , it is possible to prevent breakages such as chips or cracks from occurring on the support plate  46  as a result of this tensile force. Consequently, the mechanical strength of the support plate  46  is heightened, and durability of the probe board  22  and thus the electrical connecting apparatus  10  can be improved. 
   A resin nut made of a resin material may be used as the female screw member  30 . Also, another electrical insulating plate having approximately the same Young&#39;s modulus as that of the ceramic plate may be used as the support plate  46 . 
   An example in which the spacer  32  is prevented from moving in its axial direction by the releasable lock means consisting of the male screw members  36  and the lock tool  38  has been shown. Instead of this lock means ( 36 ,  38 ), a male screw portion may be formed at the spacer  32 , a female screw groove corresponding to the aforementioned male screw portion may be formed at the recess  34  or the through hole  20   c  of the support member  20 , and by the screwing relationship between them, the spacer  32  may be prevented from moving in its axial direction in relation to the support member  20 . 
   The present invention is not limited to the above embodiments but may be altered in various ways without departing from the spirit and scope of the present invention. For example, as the electrical connector, another electrical connector such as a wire connector may be applied, instead of the pogo pin assembly.