Abstract:
The present invention prevents damage of adjacent mounting portions caused by heat at the time of mounting of contactors and further reduces the arrangement pitch of the contactors. An electrical connecting apparatus uses at least four types of contactors different in terms of at least the shapes of seat portions and the height positions of arm portions. Each of such contactors has a seat portion mounted on a mounting portion of a board, an arm portion extending in the left-right direction from the lower end of the seat portion, and a probe tip portion extending downward from the tip end portion of the arm portion and having a probe tip at the lower end. These contactors are mounted in parallel in a cantilevered manner alternately in the front-back direction with the mounting positions to the board displaced in the left-right direction.

Description:
TECHNICAL FIELD 
   The present invention relates to an electrical connecting apparatus for use in an electrical test of a flat-plate-shaped device under test such as a semiconductor integrated circuit. 
   BACKGROUND ART 
   A flat-plate-shaped device under test such as a semiconductor integrated circuit undergoes an electrical test to determine whether or not it is manufactured in accordance with the specification. The electrical test of this kind is performed by using an electrical connecting apparatus, such as a probe card, an IC socket, a probe block, a probe unit, or the like, having a plurality of probes or contactors to be thrust to respective electrodes of the device under test. The electrical connecting apparatus of this kind is used to electrically connect the electrodes of the device under test to a tester. 
   As one of the IC probe cards of this kind, there is one in which multiple plate-shaped probes or contactors are mounted on mounting portions of a base plate or board such as a wiring board, a probe board, etc. in a cantilevered manner to supply power to multiple non-cutting integrated circuits in a semiconductor wafer form simultaneously or in several batches, as described in Patent Documents 1 and 2. 
   [Patent Document 1]
         Japanese Patent Appln. Public Disclosure No. 2005-203606       

   [Patent Document 2]
         Japanese Patent Appln. Public Disclosure No. 2005-201844       

   Each of these conventional techniques comprises at least one contactor group in which a plurality of plate-shaped contactors are arranged in a line and attaches each contactor to a mounting portion such as a wire, a connection land, etc. of a board such as a wiring board, a probe board, etc. by conductive adhesive such as solder. Mounting the contactor to the mounting portion is performed per contactor since the arrangement pitch of the contactors is narrow, which makes it difficult to mount a plurality of contactors simultaneously. 
   Also, to prevent an adjacent contactor that has been mounted from being damaged at the time of mounting a contactor to a mounting portion and to prevent contactors adjacent to one another from electrically interfering with one another in a state where they are incorporated in an IC socket, the mounting positions to the mounting portions are displaced in a direction intersecting with the arrangement direction of the contactors, that is, are arranged in zigzags. 
   Meanwhile, in recent years, the number of integrated circuits to be integrated in one semiconductor wafer increases, and thus the arrangement pitch of the electrodes is further reduced. Such a trend tends to proceed further in the future. 
   However, in each of the conventional apparatuses, the contactors in one contactor group are just divided into two sub groups whose mounting positions differ in a direction intersecting with the arrangement direction of the contactors. Thus, when each of the conventional apparatuses is to be applied to an electrical test of an integrated circuit in which the electrodes are arranged in a fine pitch as described above, the adjacent contactors will contact, and indeed the electrical test cannot be performed. 
   BRIEF SUMMARY OF THE INVENTION 
   Technical Problem 
   It is an object of the present invention to prevent damage of adjacent mounting portions caused by heat at the time of mounting of contactors and further reduce the arrangement pitch of the contactors. 
   Solution to Problem 
   An electrical connecting apparatus according to the present invention comprises a board having first, second, third, and fourth mounting portion groups each including a plurality of mounting portions spaced from one another in a front-back direction and arranged on a lower surface of the board such that the mounting portions in each of the mounting portion group are displaced in a left-right direction from the mounting portions in the other of the mounting portion groups; and first, second, third, and fourth contactor groups each including a plurality of plate-shaped contactors in which the contactors in the first, second, third, and fourth contactor groups respectively correspond to the mounting portions in the first, second, third, and fourth mounting portion groups and are mounted to corresponding mounting portions in a cantilevered manner in a state of extending from said corresponding mounting portions in the same direction, and in which the mounting positions to said board are displaced in said left-right direction. 
   Each contactor has a seat portion mounted on the corresponding mounting portion at the upper end portion, an arm portion extending in the left-right direction from the lower end of the seat portion, and a probe tip portion extending downward from the tip end portion of the arm portion and having a probe tip at the lower end. 
   The contactors in the first, second, third, and fourth contactor groups are identical in terms of the height positions of the probe tips but are different from one another in terms of the shapes of the seat portions. 
   The height positions of the arm portions of the contactors in the first contactor group are different from the height positions of the arm portions of the contactors in at least the third and fourth contactor groups. 
   Each seat portion of each contactor in the first, second, third, and fourth contactor groups may have an inclined portion inclined in the left-right direction to one side or to the other side of the board. 
   Each seat portion of each contactor in the first contactor group may be inclined on one side in the left-right direction, and the inclined portion of each seat portion of each contactor in the second, third, and fourth contactor groups may be inclined on the other side in the left-right direction. 
   The seat portions of the contactors in the first, second, third, and fourth contactor groups may be mounted on the mounting portions in a state where the mounting positions to the board are gradually distanced in the left-right direction from the positions of the probe tips further in the order of the first, second, third, and fourth contactor groups. 
   The contactors in the first, second, third, and fourth contactor groups may be placed alternately in the front-back direction in the order of the contactors in the first, third, second, and fourth contactor groups or in the order of the contactors in the first, fourth, second, and third contactor groups. 
   The contactors adjacent to one another in the front-back direction may overlap one another at parts of the arm portions, seen from the upper side. 
   The probe tips of the contactors in the first, second, third, and fourth contactor groups may be aligned on a common virtual line extending in the front-back direction. 
   The board may further have the board further has fifth, sixth, seventh, and eighth mounting portion groups each including a plurality of mounting portions at positions distanced from the mounting portions in the first, second, third, and fourth mounting portion groups at the same side in the left-right direction further than the positions of the probe tips of said respective contactors in said first, second, third, and fourth contactor groups and arranged on the lower surface such that the mounting portions in each of the fifth, sixth, seventh, and eighth mounting portion groups are displaced in said front-back direction from one another, for each group, and that the mounting portions in the fifth, sixth, seventh, and eighth mounting portion groups are placed alternately in said front-back direction. In such a case. the electrical connecting apparatus may further comprise fifth, sixth, seventh, and eighth contactor groups each including plural plate-shaped contactors in which the contactors in the fifth, sixth, seventh, and eighth contactor groups respectively correspond to said mounting portions in the fifth, sixth, seventh, and eighth mounting portion groups and are mounted on corresponding mounting portions in a cantilevered manner in a state of extending from the corresponding mounting portions to a side of the contactors in the first, second, third, and fourth contactor groups, and in which the mounting positions are displaced to the board in the left-right direction. 
   Each of said contactors in the fifth, sixth, seventh, and eighth contactor groups may have a seat portion mounted on the corresponding mounting portion at the upper end portion, an arm portion extending in said left-right direction from the lower end of the seat portion, and a probe tip portion extending downward from the tip end portion of the arm portion and having a probe tip at the lower end. 
   The contactors in the fifth, sixth, seventh, and eighth contactor groups may be identical in terms of the height positions of the probe tips but may be different from one another in terms of the shapes of the seat portions. Also, the height positions of the arm portions of the contactors in the fifth contactor group may be different from the height positions of the arm portions of the contactors in at least the seventh and eighth contactor groups. 
   The probe tips of said contactors in said first, second, third, and fourth contactor groups may be aligned on a common virtual line, and the probe tips of said contactors in said fifth, sixth, seventh, and eighth contactor groups may be aligned on another common virtual line extending in said front-back direction distanced opposite a side of said contactors in said first, second, third, and fourth contactor groups from said virtual line on which said probe tips of said contactors in said first, second, third, and fourth contactor groups are aligned. 
   The probe tips of the contactors in the fifth, sixth, seventh, and eighth contactor groups may be aligned on a second common virtual line extending in the front-back direction distanced opposite a side of the contactors in the first, second, third, and fourth contactor groups from the virtual line on which the probe tips of the contactors in the first, second, third, and fourth contactor groups are aligned. 
   ADVANTAGEOUS EFFECTS OF INVENTION 
   As the mounting positions to the board of the contactors in the first, second, third, and fourth contactor groups are displaced in the left-right direction, the contactors in the first, second, third, and fourth contactor groups are identical in terms of the height positions of the probe tips but are different from one another in terms of the shapes of the seat portions, and the height positions of the arm portions of the contactors in the first contactor group are different from the height positions of the arm portions of the contactors in at least the third and fourth contactor groups, not only the center-to-center dimension in the left-right direction of the mounting positions to the board of the contactors in the first, second, third, and fourth contactor groups adjacent to one another in the front-back direction but also the center-to-center dimension in the front-back direction of the mounting positions to the board of the contactors in the respective contactor groups adjacent to one another in the front-back direction increase. 
   As a result of the above, even when the arrangement pitch of the contactors is reduced, it is prevented that heat at the time of mounting of the contactors to the board influences the contactors and the mounting portions adjacent in the front-back direction, which prevents the adjacent mounted contactors and the adjacent mounting portions from being damaged, and the arrangement pitch of the contactors can be further reduced. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a bottom view showing one embodiment of an electrical connecting apparatus according to the present invention. 
       FIG. 2  is a front view of the electrical connecting apparatus shown in  FIG. 1 . 
       FIG. 3  is an enlarged cross-sectional view obtained along the  3 - 3  line in  FIG. 2 . 
       FIG. 4  is a partially enlarged bottom view of the electrical connecting apparatus shown in  FIG. 1 . 
       FIG. 5  is a view obtained along the  5 - 5  line in  FIG. 4 . 
       FIG. 6  is a partially enlarged perspective view showing inversely upside-down direction of the electrical connecting apparatus shown in  FIG. 1 . 
       FIG. 7  is an enlarged cross-sectional view obtained along the  7 - 7  line in  FIG. 4 . 
       FIG. 8  shows relationship between electrodes of a device under test and mounting portions of a probe board in the electrical connecting apparatus shown in  FIG. 1 . 
       FIG. 9  is an arrangement view showing an arrangement example of the mounting portions. 
       FIG. 10  explains shapes of various kinds of contactors. 
       FIG. 11  explains a method for assembling a probe board in the electrical connecting apparatus shown in  FIG. 1 . 
       FIG. 12  is an enlarged upside-down perspective view of another arrangement example of the contactors. 
       FIG. 13  is a view similar to  FIG. 9  showing another arrangement example shown in  FIG. 12 . 
   

   DETAILED DESCRIPTION OF THE INVENTION 
   Regarding Terms 
   In the present invention, in  FIG. 3 , the left-right direction is referred to as a left-right direction or an X direction (extending direction of contactors), the direction perpendicular to the drawing sheet is referred to as a front-back direction or a Y direction (arrangement direction of the contactors in each contactor group), the up-down direction is referred to as an up-down direction or a Z direction, and the plane including the X direction and the Y direction is referred to as a horizontal plane. However, these directions and plane differ depending on the posture in which a device under test is arranged in a testing apparatus. 
   Accordingly, as for the above directions and plane, the plane including the X direction and the Y direction may be determined to be within any one plane of a horizontal plane vertical to the vertical line, an inclined plane inclined to the horizontal plane, and a vertical plane vertical to the horizontal plane or may be determined to be a combination of these planes in accordance with an actual testing apparatus. 
   Also, in the present invention, the probe tip side of the contactor is referred to as a tip end side or a front side, and the opposite side is referred to as a back end side or a back side. 
   Embodiment 
   Referring to  FIGS. 1 to 10 , an electrical connecting apparatus  10  is adapted to test, as a flat-plate-shaped device under test  12 , a semiconductor wafer having multiple non-cutting integrated circuit regions (regions under test) in a matrix form and is constituted so as to enable an electrical test of the multiple integrated circuit regions or regions under test simultaneously at a time or in several batches. 
   Each region under test has a plurality of pad electrodes  14  (refer to  FIG. 7 ) in two lines spaced from each other in the left-right direction, that is, in the form of two electrode arrays. The plurality of pad electrodes  14  in the electrode array located on one side in the left-right direction constitute a first electrode group, and the plurality of pad electrodes  14  in the electrode array located on the other side in the left-right direction constitute a second electrode group. 
   The electrodes  14  in each electrode group are aligned in a line, being spaced from one another in the front-back direction. The positions in the left-right direction of the electrodes  14  in the respective electrode groups of the regions under test adjacent to one another in the front-back direction are corresponded to one another. 
   The electrical connecting apparatus  10  includes a circular wiring board  20 , a rectangular probe board  22  arranged on the lower surface of the wiring board  20 , and a plurality of contactors  24  arranged on the lower surface of the probe board  22 . 
   The wiring board  20  has at the edge portion on the upper surface of the wiring board  20  a plurality of tester lands  26  to be connected to electrical circuits of a tester and has on the lower surface and inside a plurality of wires electrically connected to the tester lands  26  in one-to-one relationship although not shown in figures. 
   The probe board  22  has a plurality of mounting portions  28  each having conductivity on the lower surface of an electrical insulating plate  30  and has a plurality of internal wires (not shown) electrically connected to the mounting portions  28  in one-to-one relationship in the electrical insulating plate  30 . 
   Although, in the example shown in the figures, the mounting portion  28  is an independent probe land electrically connected to the internal wire of the probe board  22 , it may be a part of the internal wire exposed on the lower surface of the probe board  22 . 
   Each wire of the probe board  22  is electrically connected to the aforementioned not shown wire of the wiring board  20 . Thus, each mounting portion  28  is electrically connected to the wire of the wiring board  20  in one-to-one relationship. The multiple contactors  24  and the multiple mounting portions  28  are respectively allocated per regions under test that are to be tested simultaneously. The contactors  24  and the mounting portions  28  correspond to one another and to the electrodes  14  in one-to-one relationship. 
   The wiring board  20  and the probe board  22  are relatively positioned by a plurality of positioning pins (not shown) extending through them in the thickness direction and are mutually coupled by a plurality of screw members (not shown). 
   The multiple mounting portions  28  allocated to the regions under test are divided into first, second, third, and fourth mounting portion groups each including plural mounting portions  28  spaced from one another in the front-back direction and located on one side (left side in  FIGS. 3 and 4  in the example shown in the figures) in the left-right direction in relation to a first virtual line VL 1  extending in the front-back direction located at the center of the electrodes  14  in the left-right direction and fifth, sixth, seventh, and eighth mounting portion groups each including plural mounting portions  28  spaced from one another in the front-back direction and located on the other side (right side in  FIGS. 3 and 4  in the example shown in the figures) in the left-right direction in relation to the first virtual line VL 1 . 
   In the example shown in the figures, the mounting portions in the first, second, third, and fourth mounting portion groups are shown by adding alphabets a, b, c, and d to their numerals  28 , and the mounting portions in the fifth, sixth, seventh, and eighth mounting portion groups are shown by adding alphabets a, b, c, and d to their numerals  28 . 
   As shown in  FIGS. 3 ,  4 , and  9 , the mounting portions  28   a ,  28   b ,  28   c , and  28   d  in the first, second, third, and fourth mounting portion groups are formed on the board  22  such that they are mutually distanced in the left-right direction, and such that their positions in the left-right direction are distanced from the first virtual line VL 1  further in the order of the mounting portions in the first, second, third, and fourth mounting portion groups. 
   In the same manner as above, the mounting portions  28   a ,  28   b ,  28   c , and  28   d  in the fifth, sixth, seventh, and eighth mounting portion groups are also formed on the board  22  so that they are mutually distanced in the left-right direction, and so that their positions in the left-right direction are distanced from the first virtual line VL 1  further in the order of the mounting portions in the fifth, sixth, seventh, and eighth mounting portion groups. 
   Each of the mounting portions  28   a ,  28   b ,  28   c , and  28   d  in each mounting portion group of the first, second, third, and fourth mounting portion groups is displaced, for each group, in the front-back direction from the mounting portions in the other mounting portion groups and is placed such that these mounting portions are repeatedly arranged in the front-back direction in the order of the mounting portions  28   a ,  28   d ,  28   b ,  28   c ,  28   a . . . .    
   In the same manner as above, each of the mounting portions  28   a ,  28   b ,  28   c , and  28   d  in the fifth, sixth, seventh, and eighth mounting portion groups is also displaced for each group, in the front-back direction from the mounting portions in the other mounting portion groups and is placed such that these mounting portions are repeatedly arranged in the front-back direction in the order of the mounting portions  28   a ,  28   d ,  28   b ,  28   c ,  28   a . . . .    
   As shown in  FIG. 10 , each contactor  24  is a plate-shaped blade-type probe comprising a plate-shaped seat portion  32  mounted on the corresponding mounting portion  28  at the upper end portion, a plate-shaped arm portion  34  extending in the left-right direction from the lower end of the seat portion  32 , and a plate-shaped probe tip portion  36  extending downward from the tip end portion of the arm portion  34 . The probe tip portion  36  has a probe tip  38  at its lower end. 
   The seat portion  32  and the arm portion  34  have holes passing through them in the thickness direction. The hole of the arm portion  34  is an elongated hole elongated in the left-right direction. Accordingly, the arm portion  34  is elastically deformed easily when overdrive acts on the contactor  24 . 
   Each contactor  24  is mounted to the corresponding mounting portion  28  of the probe board  22  in a cantilevered manner at the seat portion  32  with its thickness direction being the front-back direction and in a state where the probe tip  38  accords with a second or third virtual line VL 2  or VL 3  corresponding to the positions of the electrodes  14  of one or the other of the aforementioned electrode arrays. 
   The multiple contactors  24  allocated to each of the regions under test are divided into first, second, third, and fourth contactor groups each including plural contactors  24  displaced from one another in the front-back direction and located on one side in the left-right direction in relation to the first virtual line VL 1  and fifth, sixth, seventh, and eighth contactor groups each including plural contactors  24  displaced from one another in the front-back direction and located on the other side in the left-right direction in relation to the first virtual line VL 1 . 
   In the example shown in the figures, the contactors in the first, second, third, and fourth contactor groups are shown by adding alphabets a, b, c, and d to their numerals  24 , and the contactors in the fifth, sixth, seventh, and eighth contactor groups are shown by adding alphabets a, b, c, and d to their numerals  24 . 
   As shown in  FIGS. 3 to 7 , the contactors  24   a ,  24   b ,  24   c , and  24   d  in the first, second, third, and fourth contactor groups are attached to the probe board  22  such that they are mutually distanced in the left-right direction, and such that their mounting positions to the probe board  22  in the left-right direction are distanced from the second virtual line VL 2  further in the order of the contactors in the first, second, third, and fourth contactor groups. 
   In the same manner as above, the contactors  24   a ,  24   b ,  24   c ,  24   d  in the fifth, sixth, seventh, and eighth contactor groups are also attached to the probe board  22  such that they are mutually distanced in the left-right direction, and such that their mounting positions to the probe board  22  in the left-right direction are distanced from the third virtual line VL 3  further in the order of the contactors in the fifth, sixth, seventh, and eighth contactor groups. 
   Each of the contactors  24   a ,  24   b ,  24   c , and  24   d  in the first, second, third, and fourth contactor groups is displaced in the front-back direction from the contactors in the other contactor groups and is placed such that these contactors are repeatedly arranged in the front-back direction in the order of the contactors  24   a ,  24   d ,  24   b ,  24   c ,  24   a . . . .    
   In the same manner as above, each of the contactors  24   a ,  24   b ,  24   c , and  24   d  in the fifth, sixth, seventh, and eighth contactor groups is also displaced in the front-back direction from the contactors in the other contactor groups and is placed such that these contactors are repeatedly arranged in the front-back direction in the order of the contactors  24   a ,  24   d ,  24   b ,  24   c ,  24   a . . . .    
   Since the distance dimension from the electrode group to each mounting portion  28  differs depending on the mounting portion group, the respective locations of the contactors  24   a ,  24   b ,  24   c , and  24   d  differ from one another. This will be explained below with reference to  FIG. 10 . 
   The height positions of the probe tips of the contactors  24   a ,  24   b ,  24   c , and  24   d  in the respective contactor groups from the corresponding mounting portions  28   a ,  28   d ,  28   b ,  28   c  (height dimensions of the contactors  24  from the corresponding mounting portions  28  to the probe tips  38 ) are identical. 
   The dimensions of the arm portions  34  in the up-down direction (width dimensions), the dimensions of the seat portions  32  and the arm portions  34  in the front-back direction (thickness dimensions), and the dimensions of the arm portions  34  in the left-right direction (length dimensions) are also identical to one another, respectively. 
   The height dimensions from the mounting portions  28  of the seat portions  32  of the contactors  24   a ,  24   b  in the first, second, fifth, and sixth contactor groups (height dimensions of the contactors  24  from the corresponding mounting portions  28  to the probe tips  38 ) are identical. 
   The height dimensions from the mounting portions  28  of the seat portions  32  of the contactors  24   c ,  24   d  in the third, fourth, seventh, and eighth contactor groups are mutually identical, but are greater than the height dimensions from the mounting portions  28  of the seat portions  32  of the contactors  24   a ,  24   b  in the first, second, fifth, and sixth contactor groups as much as the added amount of several micrometers to several tens of micrometers or so to the width dimensions of the arm portions  34 . 
   From the foregoing explanation, the height dimensions from the mounting portions  28  of the arm portions  34  of the contactors  24   c ,  24   d  in the third, fourth, seventh, and eighth contactor groups are greater than the height dimensions from the mounting portions  28  of the arm portions  34  of the contactors  24   a ,  24   b  in the first, second, fifth, and sixth contactor groups. 
   The dimensions in the front-back direction of the probe tip portions  36  and the probe tips  38  of the contactors  24   a ,  24 ,  24   c , and  24   d  in the respective contactor groups (thickness dimensions) are mutually identical, but are smaller than the thickness dimensions of the seat portions  32  and the arm portions  34 . 
   The dimensions in the up-down direction of the probe tip portions  36  of the contactors  24   a ,  24   b  in the first, second, fifth, and sixth contactor groups (length dimensions) are identical. However, the dimensions in the up-down direction of the probe tip portions  36  of the contactors  24   c ,  24   d  in the third, fourth, seventh, and eighth contactor groups (length dimensions) are mutually identical, but are smaller than those of the probe tip portions  36  of the contactors  24   a ,  24   b  in the first, second, fifth, and sixth contactor groups as much as the difference between the height dimensions of the seat portions  32 . 
   The length dimensions in the left-right direction of the seat portions  32  of the contactors  24   a ,  24   b ,  24   c ,  24   d  in the first to eighth contactor groups (dimensions from the back ends of the mounting parts of the seat portions  32  to the corresponding mounting portions  28  to the arm portions  34 ) gradually increase in the order of the contactors  24   a ,  24   b ,  24   c ,  24   d.    
   The seat portions  32  of the contactors  24   a  in the first and fifth contactor groups have inclined surfaces  40   a  directing obliquely downward on a side opposite the electrode group side. The seat portions  32  of the contactors  24   b  in the second and sixth contactor groups have inclined surfaces  40   b  directing obliquely downward on the opposite side to the electrode group side. 
   The seat portions  32  of the contactors  24   c  in the third and seventh contactor groups have inclined surfaces  40   c  directing obliquely upward on the electrode group side. The seat portions  32  of the contactors  24   d  in the fourth and eighth contactor groups have inclined surfaces  40   d  directing obliquely upward on the electrode group side. 
   Each contactor  24  is attached to a predetermined mounting portion  28  with use of a heat source such as laser and conductive adhesive such as solder. 
   The probe board  22  having the above contactors  24  can be assembled in the following procedures. 
   First, as shown in  FIG. 11(A) , the probe board  22  having the multiple mounting portions is prepared. In parallel with this, the aforementioned multiple contactors  24   a ,  24   b ,  24   c , and  24   d  are prepared. 
   Next, as shown in  FIG. 11(B) , the contactors  24   a  in the first contactor group are attached to the predetermined mounting portions  28   a . Next, as shown in  FIG. 11(C) , the contactors  24   b  in the second contactor group are attached to the predetermined mounting portions  28   b . Next, as shown in  FIG. 11(D) , the contactors  24   c  in the third contactor group are attached to the predetermined mounting portions  28   c . Next, as shown in  FIG. 11(E) , the contactors  24   d  in the fourth contactor group are attached to the predetermined mounting portions  28   d.    
   As a result of the above operations, as shown in  FIG. 11(E) , the probe board  22  having the respective contactors  24  in the first, second, third, and fourth contactor groups is assembled. 
   The contactors  24  in the fifth, sixth, seventh, and eighth contactor groups are attached to the predetermined mounting portions in the same manner as above. 
   The electrical connecting apparatus  10  is attached to the tester in a state where the wiring board  20  is on the upper side, and where the contactors  24  are on the lower side. In a state of being attached to the tester, the electrical connecting apparatus  10  is thrust to the pad electrodes  14  of the device under test  12  at the probe tips  38  of the respective contactors  24 . 
   By doing so, overdrive acts on each contactor  24 , and each contactor  24  is elastically deformed at the arm portion  34 . In this state, power is supplied from the tester to a predetermined contactor  24  via the tester land  26 , the wire of the wiring board  20 , and the wire of the probe board  22 , and an electrical signal is outputted from the predetermined contactor  24  to the tester. 
   In the electrical connecting apparatus  10 , the center-to-center dimension in the left-right direction of the mounting positions to the board  22  of the contactors  24  adjacent to one another in the front-back direction and the center-to-center dimension in the front-back direction of the mounting positions of the contactors  24  adjacent to one another in the front-back direction respectively increase. 
   As a result of the above, even when the arrangement pitch of the contactors  24  is reduced, it is prevented that heat at the time of mounting of the contactors  24  influences the adjacent mounting portions  28 , which prevents the adjacent mounting portions  28  from being damaged. Also, since the seat portions  34  and the arm portions  36  of the adjacent contactors  24  are not opposed to each other, electrical interference between the adjacent contactors  24  is prevented or reduced. 
   Also, since the contactors  24  in the first, second, third, and fourth contactor groups and the contactors  24  in the fifth, sixth, seventh, and eighth contactor groups are arranged to be symmetrical centering on the first virtual line VL 1 , the electrical connecting apparatus  10  can be applied to an electrical test of a device under test having more electrodes  14  on each region under test. 
   In the above embodiments, the contactors  24   a ,  24   b ,  24   c , and  24   d  in the first, second, third, and fourth contactor groups and the contactors  24   a ,  24   b ,  24   c , and  24   d  in the fifth, sixth, seventh, and eighth contactor groups are placed such that these contactors are repeatedly arranged in the front-back direction in the order of the contactors  24   a ,  24   d ,  24   b ,  24   c ,  24   a . . . .    
   However, as shown in  FIG. 12 , the contactors  24   a ,  24   b ,  24   c , and  24   d  in the first, second, third, and fourth contactor groups and the contactors  24   a ,  24   b ,  24   c , and  24   d  in the fifth, sixth, seventh, and eighth contactor groups may be placed such that these contactors are repeatedly arranged in the front-back direction in the order of the contactors  24   a ,  24   c ,  24   b ,  24   d ,  24   a . . . .    
   In the above case, the probe board  22  in which the mounting portions  28   a ,  28   b ,  28   c , and  28   d  are arranged as shown in  FIG. 13  is used. 
   The present invention do not need to comprise either the contactors  24   a ,  24   b ,  24   c , and  24   d  in the first, second, third, and fourth contactor groups or the contactors  24   a ,  24   b ,  24   c , and  24   d  in the fifth, sixth, seventh, and eighth contactor groups. 
   Also, the present invention can be applied not only to an electrical connecting apparatus for a device under test having a plurality of electrodes in two arrays on the region under test but also to an electrical connecting apparatus for a device under test having a plurality of electrodes in one array or three or more arrays on the region under test. 
   Further, the present invention can be applied to an electrical connecting apparatus in which contactors are attached directly to a wiring board. 
   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.