Abstract:
The present invention relates to a probe stylus  1  for an inspection of semiconductor device in a state of wafer. When a large number of pad  5  are disposed in a semiconductor device, setting of the probe styluses  1  onto a probe card, on which a semiconductor to be inspected shall be mounted, is difficult. An objet of the present invention is to improve the form of the probe stylus to solve this problem.  
     The object is attained by a probe stylus according to the present invention. The probe stylus  1  is comprised of a first electrically conductive member  2,  a second electrically conductive member  3,  and an insulating member  4  disposed between the first and second electrically conductive members  2,3,  wherein the first and second electrically conductive members  2,3  have a form of a needle and they form a single needle. In an embodiment, the first and second electrically conductive members have a half round cross section. In another embodiment, each of the first and second electrically conductive members has a resilient portion at their tip portion. In another embodiment, the first electrically conductive member is covered with the insulating member, and the insulating member is covered with the second electrically conductive member. In further another embodiment, a slit is disposed between the first and second electrically conductive members.

Description:
BACKGROUND OF THE INVENTION  
         [0001]    1. Field of the Invention  
           [0002]    The present invention relates to a probe stylus for inspecting a semiconductor at a wafer state.  
           [0003]    2. Description of the Prior Art  
           [0004]    A probe stylus in the prior art is constituted as a single electrically conductive needle. In a high precise inspection of a semiconductor device at a wafer state, probe styluses for forcing and probe styluses for sensing are connected to pads disposed in a semiconductor. And these probe styluses are connected to form a Kelvin connection. In such a probe stylus, a cantilever type probe stylus and a perpendicular type probe stylus are known. The cantilever type probe stylus contacts obliquely with a pad disposed in a semiconductor device, and the perpendicular type probe stylus contacts perpendicularly with a pad, at an inspection of a semiconductor.  
           [0005]    At an inspection of an I/O of a semiconductor device, for example, a high speed logic element, when an output data of a driver of a tester is inputted into a signal input terminal of a semiconductor, and the output from the output terminal of the semiconductor is received by a comparator of the tester, there is case that a dead band appears. For eliminating such a dead band, it is proposed to use a signal line specialized for transferring the data signal from the output terminal of the tester to the input terminal of the semiconductor and another signal line specialized for transferring the signal from the output terminal of the semiconductor to the comparator of the tester. A dead band means a period, in which the tester cannot judge the semiconductor, because of a conflict of the signals from the output terminal of the semiconductor and the data signal from the output terminal of the driver of the tester.  
           [0006]    Many probe styluses have already been known, which allows to inspect precisely a semiconductor device at a wafer state, even when a large number of pads are disposed in the semiconductor device. Such probe styluses are disclosed, for example, in Japanese Patent Applications JP-A-5-144895, JP-Utility-Model-A-1-174932, JP-A-Utility-Model-61-104380, JP-A2-124469 and JP-A-4-288847.  
           [0007]    [0007]FIG. 62 is a perspective view of a probe stylus disclosed in JP-A-5-144895. FIG. 62 shows a state that a probe stylus  201  contacts with a pad  204  disposed in a semiconductor. The probe stylus  201  is a so-called cantilever type probe stylus constituted of a first electrically conductive member  202  and a second electrically conductive member  203 , which are jointed to each other so as to form a branching structure.  
           [0008]    [0008]FIG. 63 is a cross sectional view of a probe stylus disclosed in JP-Utility-Model-A-1-174932. FIG. 63. shows that a probe stylus  211  contacts with a pad  216  disposed in a semiconductor. The probe stylus  211  is a so-called perpendicular type probe stylus constituted of a first electrically conductive member  212 , a second electrically conductive member  203  and an insulating member  214  disposed between the first and second probe stylus. The first and second electrically conductive members  212 ,  213 , have a form of a conventional perpendicular type probe stylus. The first and second electrically conductive members  212 ,  213  and the insulating member  214  are adhered to each other by an adhesive  215 .  
           [0009]    [0009]FIG. 64 is a cross sectional view of a probe stylus disclosed in JP-Utility-Model-A-61-104380. FIG. 64 shows that a probe stylus  221  contacts with a pad disposed in a semiconductor. The probe stylus  221  is a so-called cantilever type probe stylus constituted of a first electrically conductive member  222 , a second electrically conductive member  223 , and insulating member  224  disposed between and around the first and second electrically conductive members  222 ,  223 . The first electrically conductive member  222  has a form of a conventional cantilever type probe stylus. The second electrically conductive member  223  is thinner than the first electrically conductive member  222 . The first and second electrically conductive members  222 ,  223  are fixed to each other by the insulating member  224  so that they form a single body.  
           [0010]    [0010]FIG. 65 ( a ) is a side view of a probe stylus disclosed in JP-A-2-124469, FIG. 65( b ) is a E 1 -E 1  cross-sectional view of FIG. 65 ( a ). The probe stylus  231  is a so-called cantilever type probe stylus constituted of a first electrically conductive member for forcing  232 , a second electrically conductive member for sensing  233 , and an insulating member  234  disposed between the first and second electrically conductive members  232 ,  233 . The first electrically conductive member for forcing  232  has a form of a conventional cantilever type probe stylus. The outside of the first electrically conductive member  232  is covered with the insulating member  234 , and the outside of the insulating member  234 , in turn, is covered with the second electrically conductive members  233 .  
           [0011]    Also, JP-A-4-288847 discloses a similar probe stylus constituted of a first electrically conductive member for forcing  232 , which has a form of a conventional cantilever type probe stylus and is covered with an insulating member  234 , and a second electrically conductive member for sensing  233 , which covers the outside of the insulating member  234 .  
           [0012]    The probe stylus of the prior art, constituted as a single electrically conductive needle, has following drawbacks. In general, a large number of probe styluses are required for high precision inspection of a semiconductor in a wafer state, when a large number of pad is disposed in the semiconductor device. However, the setting of the probe styluses of the prior art onto a probe card are difficult, when a large number of pads are disposed in a semiconductor device.  
           [0013]    Another drawback is that a probe card tends to warp, when perpendicular type probe styluses contact with the pads disposed in a semiconductor device.  
         SUMMARY OF THE INVENTION  
         [0014]    An object of the present invention is to eliminate these drawbacks of the probe stylus of the prior art.  
           [0015]    Another object is to propose a probe stylus, which allows to inspect precisely a semiconductor at a wafer state, even when a large number of the pads are disposed in a semiconductor device.  
           [0016]    Another object is to propose a probe stylus, which does not cause a warp of the probe card, when the probe styluses contact with the pads, even when a large number of pads are disposed in a semiconductor device.  
           [0017]    The object is attained by a probe stylus according to Claim 1.  
           [0018]    In an embodiment the probe stylus of the present invention, the cross section of each of the first and second electrically conductive members perpendicular to their longitudinal direction is half round.  
           [0019]    In another embodiment the probe stylus of the present invention, each of the first and second electrically conductive members has a resilient portion at their tip portion, where the probe stylus contacts with a pad disposed in a semiconductor device.  
           [0020]    In another embodiment the probe stylus of the present invention, the first electrically conductive member is covered with the insulating member, and the insulating member is covered with the second electrically insulating member, and the first and second electrically conductive members are electrically connected to each other at their tip portion.  
           [0021]    In another embodiment the probe stylus of the present invention, the first electrically conductive member is covered with the insulating member, and the insulating member is covered with the second electrically insulating member, and the first and second electrically conductive members are not electrically connected to each other at their tip portion, but are connected to each other through a pad disposed in a semiconductor device at an inspection of the semiconductor device.  
           [0022]    In another embodiment the probe stylus of the present invention, the probe stylus is a cantilever type probe stylus, and a slit is disposed between the first and second electrically conductive members at their tip portion, where the probe stylus contacts with a pad disposed in a semiconductor device, the slit opens when the probe stylus contacts with a pad disposed in the semiconductor device so that the first and second electrically conductive members separate from each other. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0023]    [0023]FIG. 1 is a schematic side view of a probe stylus as a first embodiment of the present invention.  
         [0024]    [0024]FIG. 2 is a plan view of the probe stylus seen from the side A in FIG. 1.  
         [0025]    [0025]FIG. 3 is a cross sectional view of the probe stylus along B-B line in FIG. 1.  
         [0026]    [0026]FIG. 4 is a cross sectional view of a probe card having probe styluses according to the first embodiment of the present invention.  
         [0027]    [0027]FIG. 5 is a detailed cross sectional view of the a connecting portion of a probe stylus and the probe card of FIG. 4.  
         [0028]    [0028]FIG. 6 is a plan view of the connecting portion of a probe stylus and the probe card seen from the side D in FIG. 5.  
         [0029]    [0029]FIG. 7 is a schematic side view of a probe stylus as a second embodiment of the present invention.  
         [0030]    [0030]FIG. 8 is a cross sectional view of the probe stylus along E-E line in FIG. 7.  
         [0031]    [0031]FIG. 9 is a plan view of a probe stylus as a third embodiment of the present invention.  
         [0032]    [0032]FIG. 10 is a side view of the probe stylus seen from the side F in FIG. 9.  
         [0033]    [0033]FIG. 11 is a cross sectional view of the probe stylus along G-G line in FIG. 11.  
         [0034]    [0034]FIG. 12 is a plan view of the connecting portion of a probe stylus according to the third embodiment and a probe card seen from the bottom side.  
         [0035]    [0035]FIG. 13 is a plan view of a probe stylus according to the fourth embodiment.  
         [0036]    [0036]FIG. 14 is a cross sectional view of the probe stylus along H-H line in FIG. 13.  
         [0037]    [0037]FIG. 15 is a schematic side view of a probe stylus as a fifth embodiment of the present invention.  
         [0038]    [0038]FIG. 16 is a cross sectional view of the probe stylus along I-I line in FIG. 15.  
         [0039]    [0039]FIG. 17 is a cross sectional views of a probe card having probe styluses according to the fifth embodiment of the present invention.  
         [0040]    [0040]FIG. 18 is a detailed cross sectional view of the probe card at the connecting portion of a probe card and a probe stylus according to the fifth embodiment, showing an example of the connection between them.  
         [0041]    [0041]FIG. 19 a detailed cross sectional view of the probe card at the connecting portion of a probe card and a probe stylus according to the fifth embodiment, showing another example of the connection between them.  
         [0042]    [0042]FIG. 20 is a schematic side view of a probe stylus as a sixth embodiment of the present invention.  
         [0043]    [0043]FIG. 21 is a cross sectional view of the probe stylus along K-K line in FIG. 20.  
         [0044]    [0044]FIG. 22 is a schematic side view of a probe stylus as a seventh embodiment of the present invention.  
         [0045]    [0045]FIG. 23 is a cross sectional view of the probe stylus along L-L line in FIG. 22.  
         [0046]    [0046]FIG. 24 is a schematic side view of a probe stylus as an eighth embodiment of the present invention.  
         [0047]    [0047]FIG. 25 is a cross sectional view of the probe stylus along M-M line in FIG. 24.  
         [0048]    [0048]FIG. 26 is a schematic side view of a probe stylus as a ninth embodiment of the present invention.  
         [0049]    [0049]FIG. 27 is a cross sectional view of the probe stylus along N-N line in FIG. 26.  
         [0050]    [0050]FIG. 28 is a schematic side view of a probe stylus as a tenth embodiment of the present invention.  
         [0051]    [0051]FIG. 29 is a cross sectional view of the probe stylus along O-O line in FIG. 28.  
         [0052]    [0052]FIG. 30 is a schematic side view of a probe stylus as an eleventh embodiment of the present invention.  
         [0053]    [0053]FIG. 31 is a cross sectional view of the probe stylus along P-P line in FIG. 30.  
         [0054]    [0054]FIG. 32 is a schematic side view of a probe stylus as a twelfth embodiment of the present invention.  
         [0055]    [0055]FIG. 33 is a cross sectional view of the probe stylus along Q-Q line in FIG. 32.  
         [0056]    [0056]FIG. 34 is a schematic side view of a probe stylus as a thirteenth embodiment of the present invention.  
         [0057]    [0057]FIG. 35 is a cross sectional view of the probe stylus along R-R line in FIG. 34.  
         [0058]    [0058]FIG. 36 is a schematic side view of a probe stylus as a fourteenth embodiment of the present invention.  
         [0059]    [0059]FIG. 37 is a cross sectional view of the probe stylus along S-S line in FIG. 36.  
         [0060]    [0060]FIG. 38 is a schematic side view of a probe stylus as a fifteenth embodiment of the present invention.  
         [0061]    [0061]FIG. 39 is a cross sectional view of the probe stylus along T-T line in FIG. 38.  
         [0062]    [0062]FIG. 40 is a schematic side view of a probe stylus as a sixteenth embodiment of the present invention.  
         [0063]    [0063]FIG. 41 is a cross sectional view of the probe stylus along U-U line in FIG. 40.  
         [0064]    [0064]FIG. 42 is a schematic side view of a probe stylus as a seventeenth embodiment of the present invention.  
         [0065]    [0065]FIG. 43 is a cross sectional view of the probe stylus along V-V line in FIG. 42.  
         [0066]    [0066]FIG. 44 is a cross sectional views of a connecting portion between a probe card a probe stylus according to the seventeenth embodiment of the present invention.  
         [0067]    [0067]FIG. 45 is a schematic side view of a probe stylus as a eighteenth embodiment of the present invention.  
         [0068]    [0068]FIG. 46 is a cross sectional view of the probe stylus along W-W line in FIG. 45.  
         [0069]    [0069]FIG. 47 is a schematic side view of a probe stylus as a nineteenth embodiment of the present invention.  
         [0070]    [0070]FIG. 48 is a cross sectional view of the probe stylus along X-X line in FIG. 47.  
         [0071]    [0071]FIG. 49 is a detailed cross sectional view of an example of the connecting portion between the probe card and a substrate of a probe stylus according to the nineteenth embodiment.  
         [0072]    [0072]FIG. 50 is a detailed cross sectional view of another example of the connecting portion between the probe card and a substrate of a probe stylus according to the nineteenth embodiment.  
         [0073]    [0073]FIG. 51 is a schematic side view of a probe stylus as a twentieth embodiment of the present invention.  
         [0074]    [0074]FIG. 52 is a cross sectional view of the probe stylus along Y-Y line in FIG. 51.  
         [0075]    [0075]FIG. 53 is a schematic side view of a probe stylus as a twenty-first embodiment of the present invention.  
         [0076]    [0076]FIG. 54 is a cross sectional view of the probe stylus along Z-Z line in FIG. 53.  
         [0077]    [0077]FIG. 55 is a schematic side view of a probe stylus as a twenty-second embodiment of the present invention.  
         [0078]    [0078]FIG. 56 is a cross sectional view of the probe stylus along A 1 -A 1  line in FIG. 55.  
         [0079]    [0079]FIG. 57 is a schematic plan view of a probe stylus according to the twenty-third embodiment at a state that the probe stylus is not contacting with a pad disposed in a semiconductor.  
         [0080]    [0080]FIG. 58 is a schematic plan view of a probe stylus according to the twenty-third embodiment at a state that the probe. stylus is contacting with a pad disposed in a semiconductor.  
         [0081]    [0081]FIG. 59 is a side view of a probe stylus seen from the side B 1  in FIG. 57.  
         [0082]    [0082]FIG. 60 is a cross sectional view of an example of a probe stylus, (a) shows a cross section along the line C 1 -C 1  in FIG. 57, (b) shows a cross section along the line D 1 -D 1  in FIG. 57.  
         [0083]    [0083]FIG. 61 is a cross sectional view of another example of a probe stylus, which has a form different from that of FIG. 60, (a) shows a cross section along the line C 1 -C 1  in FIG. 57, (b) shows a cross section along the line D 1 -D 1  in FIG. 57.  
         [0084]    [0084]FIG. 62 is a perspective view of a probe stylus disclosed in JP-A-5-144895.  
         [0085]    [0085]FIG. 63 is a cross sectional view of a probe stylus disclosed in JP-Utility-Model-A-5-144895.  
         [0086]    [0086]FIG. 64 is a cross sectional view of a probe stylus disclosed in JP-Utility-Model-A-61-104380.  
         [0087]    [0087]FIG. 65 ( a ) is a side view of a probe stylus disclosed in JP-A-61-104380, FIG. 65( b ) is a E 1 -E 1  cross sectional view of FIG. 65 ( a ). 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
     FIRST EMBODIMENT  
       [0088]    The first embodiment of the probe stylus according to the present invention is explained below, referring to FIGS.  1 - 6 . FIGS. 1 and 2 show that the probe stylus  1  is contacting with a pad  5  disposed in a semiconductor device.  
         [0089]    The probe stylus  1  of the first embodiment of the present invention is a so-called cantilever type probe stylus. Each of the first and second electrically conductive members  2 , 3  has a form of needle. The cross section perpendicular to the longitudinal direction of the needle is half round. Namely, each of the first and second electrically conductive member has a form of a conventional cantilever type probe stylus divided equally along its longitudinal axis. Thus, the assembly of the probe stylus of the first embodiment has a thickness substantially equal to the conventional probe stylus. The first and second electrically conductive members  2 ,  3  are connected to each other at their tip, where the probe stylus  1  contacts with a pad  5  disposed in a semiconductor device. In this embodiment, the first and second electrically conductive members  2 ,  3  are arranged so that one of them is positioned over the other.  
         [0090]    Referring to FIG. 4, a base substrate  12  of the probe card  11  has a center hole  13 , and a probe stylus  1  is fixed to a ring  14  by a synthetic resin  15 . FIG. 5 shows a detailed cross sectional view of the part C in FIG. 4 framed by a broken line. FIG. 6 is a plan view of the connecting portion of a probe stylus and the probe card seen from the side D in FIG. 5. Referring to FIG. 6, first and second lands  16 ,  17  are disposed on the base substrate  12  of the probe card  1 . And the first electrically conductive member  2  contacts with a first land  16 , the second electrically conductive member  3  contacts with a second land  17 . Reference numeral  18  denotes soldering portion connecting the first and second electrically conductive members  2 ,  3  with the first and second land  16 ,  17 , respectively. The structure of the other part is similar to that shown in FIGS. 1,4.  
         [0091]    The function of the probe card and the probe stylus is explained below.  
         [0092]    At a precise inspection of a semiconductor device at a wafer state, a probe stylus  1  is brought in contact with a pad  5  disposed in a semiconductor device. And one of the first and second electrically conductive member  2 ,  3  is used as an electrically conductive member for forcing, and the other is used as an electrically conducting member for sensing. In this case, the first and second electrically conductive members are connected at their tip, therefore, the value of voltage and/or electric current can be compensated up to the tip of the probe stylus  1 , when a Kelvin connection is formed at the tips of the first and second electrically conductive members  2 ,  3 .  
         [0093]    At an inspection of an I/O of a semiconductor device at a wafer state, the probe stylus  1  is brought in contact with a pad  5  disposed in the semiconductor device, and one of the first and second electrically conductive member  2 ,  3  is used as an electrically conductive member for driving and the other is used as an electrically conductive member for tester. In this case, the first and second electrically conductive members are contacted electrically to each other at their tip. Therefore, the line specialized for transferring output data signal from the driver to the pad  5  disposed in the semiconductor device, and the line specialized for transferring the output data signal from the pad  5  to the comparator of the tester are assured up to the tip of the probe stylus.  
         [0094]    As explained, the probe stylus  1  according to the first embodiment of the present invention has a first electrically conductive member  2  and a second electrically conductive member  3 . Therefore, such a probe stylus functions equivalent to two probe styluses of the prior art. As a result, by contacting one probe stylus to one of the pads disposed in a semiconductor device, it is possible to eliminate so-called dead band in the comparator in a precise inspection of a semiconductor device at a wafer state, or in an inspection of an I/O of a semiconductor device at a wafer state. Also in a case that a large number of pads are disposed in a semiconductor device, corresponding large number of probe styluses can be disposed on a probe card, so that so-called dead band in the-comparator can be eliminated in such a precise inspection of a semiconductor device at a wafer state, or in an inspection of an I/O of a semiconductor device at a wafer state.  
         [0095]    A probe stylus according to the first embodiment of the present invention functions equivalently to two probe styluses of the prior art, hence, the number of probe styluses  1  to be attached to a probe card and/or the area required for the arrangement of the probe stylus in a probe card can be reduced, as a result, the fabrication cost can be reduced.  
         [0096]    Additionally, according to the first embodiment of the present invention, each of the first and second electrically conductive members has a half round cross section perpendicular to the longitudinal direction. Therefore, the thickness of the probe stylus according to the first embodiment is smaller than that of bundled two probe styluses of the prior art. As a result, also in a case that a large number of pads are disposed in a semiconductor device, a corresponding number of the probe styluses  1  can be attached onto a probe card.  
       SECOND EMBODIMENT  
       [0097]    In a probe stylus according to the first embodiment, the first and second electrically conductive members  2 ,  3  are connected at their tip. On the other hand, in a probe stylus according to the second embodiment of the present invention, the first and second electrically conductive members are not connected at their tip. And at an inspection of a semiconductor device, they are connected to each other through a pad disposed in a semiconductor device. The other feature is similar to that of the first embodiment.  
         [0098]    [0098]FIG. 7 shows that the probe stylus la is contacting with a pad  5  disposed in a semiconductor device. Referring to the figure, reference numerals  1   a,    2   a,    3   a  denote a probe stylus, a first electrically conductive member, and a second electrically conductive member, respectively. The first and second electrically conductive members  2   a ,  3   a  are connected by an insulating member  4   a  arranged between them. Reference numeral  5  denotes a pad disposed in a semiconductor.  
         [0099]    The structure of a probe card having probe stylus  1   a  according to the second embodiment is similar to that of the probe card shown in FIG. 4. The connection between a probe stylus  1   a  and the substrate of a probe card is similar to that shown in FIGS. 5, 6.  
         [0100]    The function of the probe card and the probe stylus is explained below.  
         [0101]    At a precise inspection of a semiconductor device at a wafer state, a probe stylus  1   a  is brought in contact with a pad  5  disposed in the semiconductor device. And one of the first and second electrically conductive member  2   a ,  3   a  is used as an electrically conductive member for forcing, and the other is used as an electrically conducting member for sensing. In this case, the first and second electrically conductive members connects electrically through the pad  5 , therefore, the value of voltage and/or electric current can be compensated up to the pad  5 , when a Kelvin connection are formed on the pad  5 .  
         [0102]    At an inspection of an I/O of a semiconductor device at a wafer state, the probe stylus  1   a  is brought in contact with a pad  5  disposed in the semiconductor device, and one of the first and second electrically conductive member  2   a ,  3   a  is used as an electrically conductive member for driving and the other is used as an electrically conductive member for tester. In this case, the first and second electrically conductive member  2   a ,  3   a  contact electrically to each other through the pad  5 . Therefore, a line specialized for transferring output data signal from the driver to the pad  5  disposed in the semiconductor device (hereinafter referred to “a line for driver”), and a line specialized for transferring the output data signal from the pad  5  to the comparator of the tester (hereinafter referred to “a line for comparator) are assured up to the pad  5 .  
         [0103]    As explained, the first and second electrically conductive members  2   a ,  3   a  in the probe stylus according to the second embodiment contact electrically to each other through a pad  5  disposed in the semiconductor at an inspection of a semiconductor device. Therefore, the value of voltage and/or electric current can be compensated up to the pad  5 , at a precise inspection of a semiconductor device at a wafer state. And a line for driver and a line for comparator are assured up to the pad  5 , at an inspection of an I/O of a semiconductor device at a wafer state. As a result, a higher precision inspection of a semiconductor device is possible.  
         [0104]    A probe stylus according to the second embodiment has similar advantages to that of a probe stylus according to the first embodiment.  
       THIRD EMBODIMENT  
       [0105]    The first and second electrically conductive members  2 , 3  in a probe stylus according to the first embodiment are so arranged that one of them is positioned over the other. On the other hand, the first and second electrically conductive members in a probe stylus according to the third embodiment are arranged side by side. The other features of a probe stylus according to the third embodiment are similar to that of the first embodiment.  
         [0106]    [0106]FIGS. 9 and 10 show that a probe stylus  1   b  contacts with a pad  5  disposed in a semiconductor device. Referring to the figures, reference numerals  1   b ,  2   b ,  3   b  denote a probe stylus, a first electrically conductive member, and a second electrically conductive member, respectively. The first and second electrically conductive members  2   b ,  3   b  are connected by an insulating member  4   b  arranged between them. Reference numeral  5  denotes a pad disposed in a semiconductor.  
         [0107]    The structure of a probe card having probe stylus  1   b  according to the third embodiment is similar to that of the probe card shown in FIG. 4. FIG. 12 corresponds to FIG. 6. An element in FIG. 12 corresponding to an element in FIGS. 6, 9 are referred by the same reference numeral. The function of each element of a probe stylus according to the third embodiment is similar to that of a probe stylus according to the first embodiment.  
         [0108]    Because the first and second electrically conductive members  2   b ,  3   b  of the probe stylus according to the third embodiment are arranged side by side, a force urges them equally, when the probe stylus  1   b  contacts with a pad  5  disposed in a semiconductor. As a result, the structural reliability of the probe stylus is improved.  
         [0109]    A probe stylus according to the third embodiment has similar advantages to that of a probe stylus according to the first embodiment.  
       FOURTH EMBODIMENT  
       [0110]    In a probe stylus according to the third embodiment, the first and second electrically conductive members  2   b ,  3   b  are connected at their tip. On the other hand, in a probe stylus according to the fourth embodiment of the present invention, the first and second electrically conductive members are not connected at their tip. And at an inspection of a semiconductor device, they are connected to each other through a pad disposed in the semiconductor device. The other feature is similar to that of the third embodiment.  
         [0111]    [0111]FIG. 13 shows that the probe stylus  1   c  is contacting with a pad  5  disposed in a semiconductor device. Referring to the figures, reference numerals  1   c ,  2   c ,  3   c  denote a probe stylus, a first electrically conductive member, and a second electrically conductive member, respectively. The first and second electrically conductive members  2   c ,  3   c  are connected by an insulating member  4   c  arranged between them. Reference numeral  5  denotes a pad disposed in a semiconductor.  
         [0112]    The structure of a probe card having probe stylus  1   c  according to the fourth embodiment is similar to that of the probe card shown in FIG. 4. The connection between a probe stylus  1   c  and the substrate of a probe card is similar to that shown in FIG. 12. The function of the probe stylus according to the fourth embodiment is similar to that of second embodiment.  
         [0113]    As explained, the first and second electrically conductive members  2   c ,  3   c  in the probe stylus according to the fourth embodiment contact electrically to each other through a pad  5  disposed in the semiconductor at an inspection of a semiconductor device. Therefore, the value of voltage and/or electric current can be compensated up to the pad  5 , at a precise inspection of a semiconductor device at a wafer state. And a line for driver and a line for comparator are assured up to the pad  5 , at an inspection of an I/O of a semiconductor device at a wafer state. As a result, a higher precision inspection of a semiconductor device becomes possible.  
         [0114]    A probe stylus according to the fourth embodiment has similar advantages to that of a probe stylus according to the third embodiment.  
       FIFTH EMBODIMENT  
       [0115]    [0115]FIG. 15 shows that the probe stylus  21  is contacting with a pad  5  disposed in a semiconductor device. Referring to the figure, reference numerals  21 ,  22 ,  23  denote a probe stylus, a first electrically conductive member, and a second electrically conductive member, respectively. The first and second electrically conductive members  22 ,  23  are connected by an insulating member  24  arranged between them. Reference numeral  5  denotes a pad disposed in a semiconductor device.  
         [0116]    The probe stylus  21  of the fifth embodiment of the present invention is a so-called perpendicular type probe stylus. Each of the first and second electrically conductive members  22 ,  23  has a form of needle. The cross section perpendicular to the longitudinal direction of the needle is half round. Namely, each of the first and second electrically conductive member  22 ,  23  has a form of a conventional perpendicular type probe stylus divided equally along its longitudinal axis. Thus, the assembly of the probe stylus of the fifth embodiment has a thickness substantially equal to the conventional perpendicular type probe stylus. The first and second electrically conductive members  22 ,  23  are connected to each other at their tip, where the probe stylus  21  contacts with a pad  5  disposed in a semiconductor device.  
         [0117]    Referring to FIG. 17, probe card  31  comprises a first substrate  32 , a second substrate  33 , a third substrate  34 , a ring  35  and wiring  36 . FIG. 18 shows a detailed cross sectional view of the part J framed by a broken line in FIG. 17. As shown in FIG. 18, a first land  37 , a second land  38  are formed at the second substrate  33 . And a fixing ring  39  fixes the probe stylus  21  to the third substrate  34 . The wiring  36  is fixed to the second substrate  33  by a soldering  40 . The structure of other elements is similar to that of the elements referred by the same reference numeral in FIGS. 15 and 17.  
         [0118]    [0118]FIG. 19 shows a different connection of the probe card and the probe stylus according to the fifth embodiment. FIG. 19 shows a detailed cross sectional view of the part J framed by a broken line in FIG. 17. Referring to FIG. 19, wiring  36  is fixed to the second substrate  33  through a first and second single contactors  41 ,  42 . A spring  43  is disposed between the hole of the second substrate and each of the first and second single contactors  41 ,  42 . The structure of the other elements is similar to that of elements referred by the same reference numeral in FIG. 18.  
         [0119]    The function of the probe stylus according to the fifth embodiment is identical to that of the first embodiment. And the advantage of the probe stylus according to the fifth embodiment is similar to that of third embodiment.  
       SIXTH EMBODIMENT  
       [0120]    In a probe stylus according to the fifth embodiment, the first and second electrically conductive members  22 ,  23  are connected at their tip. On the other hand, in a probe stylus according to the sixth embodiment of the present invention, the first and second electrically conductive members  22 ,  23  are not connected at their tip. And at an inspection of a semiconductor device, they are connected to each other through a pad disposed in a semiconductor device. The other feature is similar to that of the fifth embodiment.  
         [0121]    [0121]FIG. 20 shows that the probe stylus  21 a is contacting with a pad  5  disposed in a semiconductor device. Referring to the figure, reference numerals  21   a,    22   a ,  23   a  denote a probe stylus, a first electrically conductive member, and a second electrically conductive member, respectively. The first and second electrically conductive members  22   a ,  23   a  are connected by an insulating member  24   a  arranged between them. Reference numeral  5  denotes a pad disposed in a semiconductor.  
         [0122]    The structure of a probe card having probe styluses  21   a  according to the sixth embodiment is similar to that of probe card shown in FIG. 17. The structure of the connecting part of a probe card and a probe stylus  21   a  according to the sixth embodiment is similar to that of shown in FIGS. 18, 19.  
         [0123]    The function of the probe stylus according to the sixth embodiment is similar to that of the second embodiment of the present invention.  
         [0124]    And the advantage of the probe stylus according to the sixth embodiment is similar to that of fourth embodiment.  
       SEVENTH EMBODIMENT  
       [0125]    [0125]FIG. 22 shows that the probe stylus  51  is contacting with a pad  5  disposed in a semiconductor device. Referring to the figure, reference numerals  51 ,  52 ,  53  denote a probe stylus, a first electrically conductive member, and a second electrically conductive member, respectively. The first and second electrically conductive members  52 ,  53  are connected by an insulating member  54  arranged between them. Reference numeral  5  denotes a pad disposed in a semiconductor.  
         [0126]    The probe stylus  51  of the seventh embodiment of the present invention is a so-called perpendicular type probe stylus. Each of the first and second electrically conductive members  52 ,  53  has a form of needle. The cross section perpendicular to the longitudinal direction of the needle is half round. Namely, each of the first and second electrically conductive member has a form of a conventional perpendicular type probe stylus divided equally along its longitudinal axis. Thus, the assembly of the probe stylus of the seventh embodiment has a diameter substantially equal to the conventional probe stylus. The first and second electrically conductive members  52 ,  53  are connected to each other at their tip, where the probe stylus  1  contacts with a pad  5  disposed in the semiconductor device. A probe stylus according to the seventh embodiment of the present invention has a circular resilient portion at the tip portion of the first and second electrically conductive members  52 ,  53 , with which the probe stylus  1  contacts with a pad  5  disposed in a semiconductor device.  
         [0127]    The structure of a probe card having probe styluses  51  according to the seventh embodiment is similar to that of probe card shown in FIG. 17. The structure of the connecting part of a probe card and a probe stylus  51  according to the seventh embodiment is similar to that of shown in FIGS. 18, 19.  
         [0128]    The function of the probe stylus according to the seventh embodiment is similar to that of the first embodiment of the present invention.  
         [0129]    As explained, the probe stylus  51  according to the seventh embodiment of the present invention has a first electrically conductive member  52  and a second electrically conductive member  53 . Therefore, the probe stylus functions equivalent to two probe styluses in the prior art. As a result, by contacting one probe stylus to each pad disposed in a semiconductor device, it is possible to eliminate so-called dead band in the comparator in a precise inspection of a semiconductor device at a wafer state, or in an inspection of an I/O of a semiconductor device at a wafer state. Also in a case that a large number of pads are disposed in a semiconductor device, corresponding large number of probe styluses can be disposed on a probe card, so that so-called dead band in the comparator can be eliminated in a precise inspection of a semiconductor device at a wafer state, or in an inspection of an I/O of a semiconductor device at a wafer state.  
         [0130]    A probe stylus according to the seventh embodiment of the present invention functions equivalently to two probe stylus in the prior art, hence, the number of probe styluses  51  to be attached to a probe card and/or the area required for the arrangement of the probe stylus in a probe card can be reduced, as a result, the fabrication cost can be reduced.  
         [0131]    Because the probe stylus  51  according to the seventh embodiment is a so-called perpendicular type probe stylus, a force urges the first and second electrically conductive members  52 ,  53  equally, when the probe stylus  51  contacts with a pad  5  disposed in a semiconductor. As a result, the structural reliability of the probe stylus  51  is improved.  
         [0132]    In a probe stylus according to the seventh embodiment of the present invention, a circular resilient portion is formed at the tip portion of the first and second electrically conductive members  52 , 53 , with which the probe stylus  51  contacts with a pad  5  disposed in the semiconductor device. As a result, the impact at the contact of the probe stylus and the pad disposed in the semiconductor is absorbed by the circular resilient portion. Therefore, a warp of a probe card, which may be caused by the contact of the probe styluses and the pads, can be avoided.  
         [0133]    According to the seventh embodiment of the present invention, each of the first and second electrically conductive members  52 ,  53  has a round cross section perpendicular to the longitudinal direction. And the diameter of each of the first and second electrically conductive members is equal to that of a probe stylus in the prior art. Therefore, a current capacity of an electrically conductive member for forcing can be assured to be equal to that of probe stylus for forcing in the prior art, when any one of the first and second electrically conductive members  52 ,  53  is used as an electrically conductive member for forcing at a precise inspection of I/O of a semiconductor device.  
       EIGHTH EMBODIMENT  
       [0134]    In a probe stylus according to the seventh embodiment, the first and second electrically conductive members  52 ,  53  are connected at their tip. On the other hand, in a probe stylus according to the eighth embodiment of the present invention, the first and second electrically conductive members are not connected at their tip. And at an inspection of a semiconductor device, they are connected to each other through a pad disposed in the semiconductor device. The other feature is similar to that of the first embodiment.  
         [0135]    [0135]FIG. 24 shows that the probe stylus  61   a  is contacting with a pad  5  disposed in a semiconductor device. Referring to the figures, reference numerals  51   a,    52   a ,  53   a  denote a probe stylus, a first electrically conductive member, and a second electrically conductive member, respectively. The first and second electrically conductive members  52   a ,  53   a  are connected by an insulating member  54   a  arranged between them. Reference numeral  5  denotes a pad disposed in a semiconductor.  
         [0136]    The structure of a probe card having probe stylus  51   a  according to the eighth embodiment is similar to that of the probe card shown in FIG. 17. The connection between a probe stylus  51   a  and the substrate of a probe card is similar to that shown in FIGS. 18, 19. The function of the probe stylus and the probe card is similar to that of the second embodiment.  
         [0137]    As explained, in the probe stylus according to the eighth embodiment, the first and second electrically conductive members  52   a ,  53   a  contact electrically to each other through a pad  5  disposed in a semiconductor at an inspection of a semiconductor device. Therefore, the value of voltage and/or electric current can be compensated up to the pad  5 , at a precise inspection of a semiconductor device at a wafer state. And a line for driver and a line for comparator are assured up to the pad  5 , at an inspection of an I/O of a semiconductor device at a wafer state. As a result, a higher precision inspection of a semiconductor device becomes possible. A probe stylus according to the eighth embodiment has similar advantages to that of a probe stylus according to the seventh embodiment.  
       NINTH EMBODIMENT  
       [0138]    In a probe stylus according to the seventh embodiment, the cross section perpendicular to the longitudinal direction of the electrically conductive members  52 ,  53  is round. On the other hand, the cross section perpendicular to the longitudinal direction of a first and second electrically conductive members of a probe stylus according to the ninth embodiment is half round. Namely, each of the first and second electrically conductive member has a form of an electrically conductive member divided equally along its longitudinal axis. The other feature is similar to that of the seventh embodiment.  
         [0139]    [0139]FIG. 26 shows that the probe stylus  51   a  is contacting with a pad  5  disposed in a semiconductor device. Referring to the figure, reference numerals  51   b,    52   b ,  53   b  denote a probe stylus, a first electrically conductive member, and a second electrically conductive member, respectively. The first and second electrically conductive members  52   a ,  53   a  are connected by an insulating member  54   a . arranged between them. Reference numeral  5  denotes a pad disposed in a semiconductor.  
         [0140]    The structure of a probe card having probe stylus  51   b  according to the ninth embodiment is similar to that of the probe card shown in FIG. 17. The connection between a probe stylus  51   b  and the substrate of a probe card is similar to that shown in FIGS. 18, 19. The function of the probe stylus and the probe card is similar to that of the first embodiment.  
         [0141]    As explained, the probe stylus  51   b  according to the ninth embodiment of the present invention has a first electrically conductive member  52   b  and a second electrically conductive member  53   b . Therefore, the probe stylus  51   b  functions equivalently to two probe styluses in the prior art. As a result, by contacting one probe stylus to each pad disposed in the semiconductor device, it is possible to eliminate so-called dead band in the comparator in a precise inspection of a semiconductor device at a wafer state, or in an inspection of an I/O of a semiconductor device at a wafer state. Hence, in a case that a large number of pads are disposed in a semiconductor device, corresponding large number of probe styluses  51   b  can be disposed on a substrate of a probe card, so that so-called dead band in the comparator can be eliminated in a precise inspection of a semiconductor device at a wafer state, or in an inspection of an I/O of a semiconductor device at a wafer state.  
         [0142]    Because the probe stylus  51   b  according to the ninth embodiment functions equivalently to two probe styluses in the prior art, the number of probe styluses  51   b  to be attached to a probe card and/or the area required for the arrangement of the probe stylus  51   b  in a probe card can be reduced. As a result, the fabrication cost can be reduced.  
         [0143]    Additionally, according to the ninth embodiment of the present invention, each of the first and second electrically conductive members  52   b ,  53   b  has a half round cross section perpendicular to the longitudinal direction. Therefore, the thickness of the probe stylus according to the first embodiment is smaller than that of a bundle of two probe styluses of the prior art. As a result, also in a case that a large number of pads are disposed in a semiconductor device, a corresponding number of the probe styluses  51   b  can be attached onto a probe card.  
         [0144]    Because the probe stylus  51   b  according to the ninth embodiment is a so-called perpendicular type probe stylus, a force urges the first and second electrically conductive members  52 ,  53  equally, when a probe stylus  51   b  contacts with a pad  5  disposed in a semiconductor. As a result, the structural reliability of the probe stylus  51   b  is improved.  
         [0145]    In a probe stylus according to the ninth embodiment of the present invention, a circular resilient portion is formed at the tip portion of the first and second electrically conductive members  52   b ,  53   b , with which the probe stylus  51   b  contacts with a pad  5  disposed in the semiconductor device. As a result, the impact at the contact of the probe stylus and the pad disposed in the semiconductor is absorbed by the circular resilient portion. Therefore, a warp of a probe card, which may be caused by the contact of the probe styluses and the pads, can be avoided.  
       TENTH EMBODIMENT  
       [0146]    In a probe stylus according to the ninth embodiment, the first and second electrically conductive members  52   b ,  53   b  are connected at their tip. On the other hand, in a probe stylus according to the tenth embodiment of the present invention, the first and second electrically conductive members are not connected at their tip. And at an inspection of a semiconductor device, they are connected to each other through a pad disposed in the semiconductor device. The other feature is similar to that of the ninth embodiment.  
         [0147]    [0147]FIG. 28 shows that the probe stylus  51   a  is contacting with a pad  5  disposed in a semiconductor device. Referring to the figure, reference numerals  51   c,    52   c ,  53   c  denote a probe stylus, a first electrically conductive member, and a second electrically conductive member, respectively. The first and second electrically conductive members  52   c ,  53   c  are connected by an insulating member  54   a  arranged between them. Reference numeral  5  denotes a pad disposed in a semiconductor.  
         [0148]    The structure of a probe card having probe stylus  51   c  according to the tenth embodiment is similar to that of the probe card shown in FIG. 17. The connection between a probe stylus  51   c  and the substrate of a probe card is similar to that shown in FIGS. 18, 19. The function of the probe stylus and the probe card is similar to that of the second embodiment.  
         [0149]    As explained, the first and second electrically conductive members  52   c ,  53   c  in the probe stylus according to the tenth embodiment contact electrically to each other through a pad  5  disposed in the semiconductor at an inspection of a semiconductor device. Therefore, the value of voltage and/or electric current can be compensated up to the pad  5 , at a precise inspection of a semiconductor device at a wafer state. And a line for driver and a line for comparator are assured up to the pad  5 , at an inspection of an I/O of a semiconductor device at a wafer state. As a result, a higher precision inspection of a semiconductor device becomes possible.  
         [0150]    A probe stylus according to the tenth embodiment has similar advantages to that of a probe stylus according to the ninth embodiment.  
       ELEVENTH EMBODIMENT  
       [0151]    [0151]FIG. 30 shows that the probe stylus  61  is contacting with a pad  5  disposed in a semiconductor device. Referring to the figure, reference numerals  61 ,  62 ,  63  denote a probe stylus, a first electrically conductive member, and a second electrically conductive member, respectively. The first and second electrically conductive members  62 ,  63  are connected by an insulating member  64  arranged between them. Reference numeral  5  denotes a pad disposed in a semiconductor.  
         [0152]    The probe stylus  61  of the eleventh embodiment of the present invention is a so-called perpendicular type probe stylus. Each of the first and second electrically conductive members  62 ,  63  has a form of needle. The cross section perpendicular to the longitudinal direction of the needle is round. Namely, each of the first and second electrically conductive member  62 ,  63  has a form of a conventional perpendicular type probe stylus.  
         [0153]    A probe stylus according to the eleventh embodiment of the present invention has a Y-formed resilient portion at the tip portion of the first and second electrically conductive members  62 , 63 , with which the probe stylus  61  contacts with a pad  5  disposed in a semiconductor device. The first and second electrically conductive members  6  are connected to each other through a third electrically conductive member  65 , which is disposed between the tip of the electrically conductive members, where the probe stylus contacts with a pad disposed in a semiconductor device.  
         [0154]    The structure of a probe card having probe stylus  61  according to the eleventh embodiment is similar to that of the probe card shown in FIG. 17. The connection between a probe stylus  61  and the substrate of a probe card is similar to that shown in FIGS. 18, 19. The function of the probe stylus and the probe card is similar to that of the second embodiment.  
         [0155]    As explained, according to the eleventh embodiment, the tip portion of a probe stylus  61 , where the probe stylus contacts with a pad disposed in a semiconductor device, is widened, therefore a probe stylus  61  contacts with a pad  5  at two points. As a result, the electric resistance at the contact between the probe stylus and the pad is small. A probe stylus according to the eleventh embodiment has advantages similar to that of the seventh embodiment.  
       TWELFTH EMBODIMENT  
       [0156]    In a probe stylus according to the eleventh embodiment, the first and second electrically conductive members  62 ,  63  are connected through a third electrically conductive member  65  disposed at their tip. On the other hand, in a probe stylus according to the twelfth embodiment of the present invention, no such a third electrically conductive member for connecting the first and second electrically conductive members  62 ,  63  are disposed. And at an inspection of a semiconductor device, they are connected to each other through a pad disposed in the semiconductor device. The other feature is similar to that of the eleventh embodiment.  
         [0157]    [0157]FIG. 32 shows that the probe stylus  61   a  is contacting with a pad  5  disposed in a semiconductor device. Referring to the figure, reference numerals  61   a,    62   a ,  63   a  denote a probe stylus, a first electrically conductive member, and a second electrically conductive member, respectively. The first and second electrically conductive members  62   a ,  63   a  are connected by an insulating member  64   a  arranged between them. Reference numeral  5  denotes a pad disposed in a semiconductor.  
         [0158]    The structure of a probe card having probe stylus  61   a  according to the twelfth embodiment is similar to that of the probe card shown in FIG. 17. The connection between a probe stylus  61   a  and the substrate of a probe card is similar to that shown in FIGS. 18, 19. The function of the probe stylus and the probe card is similar to that of the second embodiment.  
         [0159]    As explained, according to the twelfth embodiment, the tip portion of a probe stylus  61   a,  where the probe stylus contacts with the pad disposed in a semiconductor device, is widened, therefore a probe stylus  61  contacts with a pad  5  at two points. As a result, the electric resistance at the contact between the probe stylus and the pad is small. A probe stylus according to the twelfth embodiment has advantages similar to that of the eighth embodiment.  
       THIRTEENTH EMBODIMENT  
       [0160]    In a probe stylus according to the eleventh embodiment, the cross section perpendicular to the longitudinal direction of the electrically conductive members  52 ,  53  is round. On the other hand, the cross section perpendicular to the longitudinal direction of a first and second electrically conductive members of a probe stylus according to the thirteenth embodiment is half round. Namely, each of the first and second electrically conductive member has a form of a first and second electrically conductive members in the eleventh embodiment divided equally along its longitudinal axis. The other feature is similar to that of the seventh embodiment.  
         [0161]    [0161]FIG. 34 shows that the probe stylus  61   b  is contacting with a pad  5  disposed in a semiconductor device. Referring to the figure, reference numerals  61   b,    62   b ,  63   b  denote a probe stylus, a first electrically conductive member, and a second electrically conductive member, respectively. The first and second electrically conductive members  62   a ,  63   a  are connected by an insulating member  64   a  arranged between them. The firsts and second electrically conductive members  62   b ,  63   b  are electrically connected by a third electrically conductive member  65   b.  Reference numeral  5  denotes a pad disposed in a semiconductor.  
         [0162]    The structure of a probe card having probe stylus  61   b  according to the thirteenth embodiment is similar to that of the probe card shown in FIG. 17. The connection between a probe stylus  61   b  and the substrate of a probe card is similar to that shown in FIGS. 18, 19. The function of the probe stylus and the probe card is similar to that of the first embodiment.  
         [0163]    A probe stylus according to the thirteenth embodiment has advantages similar to that of the ninth embodiment.  
       FOURTEENTH EMBODIMENT  
       [0164]    In a probe stylus according to the thirteenth embodiment, the first and second electrically conductive members  62   b ,  63   b  are connected through a third electrically conductive member  65   b  disposed near to their tip. On the other hand, in a probe stylus according to the fourteenth embodiment of the present invention, no such a third electrically conductive member for connecting the first and second electrically conductive members are disposed. And at an inspection of a semiconductor device, they are connected to each other through a pad disposed in a semiconductor device. The other feature is similar to that of the thirteenth embodiment.  
         [0165]    [0165]FIG. 36 shows that the probe stylus is contacting with a pad disposed in a semiconductor device. Referring to the figure, reference numerals  61   c,    62   c ,  63   c  denote a probe stylus, a first electrically conductive member, and a second electrically conductive member, respectively. The first and second electrically conductive members  62   a ,  63   a  are connected by an insulating member  64   c  arranged between them. Reference numeral  5  denotes a pad disposed in a semiconductor.  
         [0166]    The structure of a probe card having probe stylus  61   c  according to the fourteenth embodiment is similar to that of the probe card shown in FIG. 17. The connection between a probe stylus  61   c  and the substrate of a probe card is similar to that shown in FIGS. 18, 19. The function of the probe stylus and the probe card is similar to that of the second embodiment.  
         [0167]    A probe stylus according to the fourteenth embodiment has advantages similar to that of the tenth embodiment.  
       FIFTEENTH EMBODIMENT  
       [0168]    [0168]FIG. 38 shows that the probe stylus is contacting with a pad disposed in a semiconductor device. Referring to the figure, reference numerals  71 ,  72 ,  73  denote a probe stylus, a first electrically conductive member, and a second electrically conductive member, respectively. The first and second electrically conductive members  72 ,  73  are connected by an insulating member  74  arranged between them. Reference numeral  5  denotes a pad disposed in a semiconductor.  
         [0169]    The probe stylus  71  of the fifteen embodiment of the present invention is a so-called perpendicular type probe stylus. Each of the first and second electrically conductive members  72 ,  73  has a form of needle. The cross section perpendicular to the longitudinal direction of the needle is round. In this embodiment, the diameter of the second electrically conductive member  72  is smaller than that of the first electrically conductive member  73 . Namely, the assembly of the probe stylus of the fifteenth embodiment has a thickness substantially equal to the conventional probe stylus. A probe stylus according to the fifteenth embodiment of the present invention has an arc or jack-knifed resilient portion at the tip portion of the first and second electrically conductive members  72 , 73 , with which the probe stylus contacts with a pad  5  disposed in a semiconductor device. The first and second electrically conductive members  72 ,  73  are connected to each other at their tip portion, where the probe stylus contacts with a pad  5  disposed in the semiconductor device.  
         [0170]    The structure of a probe card having probe styluses  71  according to the fifteenth embodiment is similar to that of probe card shown in FIG. 17. The structure of the connecting part of a probe card and a probe stylus  71  according to the seventh embodiment is similar to that of shown in FIGS. 18, 19. The function of the probe stylus according to the fifteenth embodiment is similar to that of the first embodiment of the present invention.  
         [0171]    As explained, the probe stylus  71  according to the fifteenth embodiment of the present invention has a first electrically conductive member  72  and a second electrically conductive member  73 . Therefore, the probe stylus functions equivalent to two probe styluses in the prior art. As a result, by contacting one probe stylus to each pad disposed in the semiconductor device, it is possible to eliminate so-called dead band in the comparator in a precise inspection of a semiconductor device at a wafer state, or in an inspection of an I/O of a semiconductor device at a wafer state. Also in a case that a large number of pads are disposed in a semiconductor device, corresponding large number of probe styluses can be disposed on a probe card, so that so-called dead band in the comparator can be eliminated in a precise inspection of a semiconductor device at a wafer state, or in an inspection of an I/O of a semiconductor device at a wafer state.  
         [0172]    A probe stylus according to the fifteenth embodiment of the present invention functions equivalently to two probe stylus in the prior art, hence, the number of probe styluses  71  to be attached to a probe card and/or the area required for the arrangement of the probe stylus in a probe card can be reduced, as a result, the fabrication cost can be reduced.  
         [0173]    According to the fifteenth embodiment of the present invention, the diameter of the second electrically conductive member  73  is smaller than that of the first electrically conductive member  72 . And the diameter of the probe stylus  71  is substantially equal to that of a probe stylus of the prior art. Therefore, the thickness of the probe stylus  71  according to the fifteenth embodiment is smaller than that of bundled two probe styluses in the prior art. As a result, also in a case that a large number of pads are disposed in a semiconductor device, a corresponding number of the probe styluses  1  can be attached onto a probe card.  
         [0174]    In a probe stylus according to the fifteenth embodiment of the present invention, an arc or jack-knifed resilient portion is formed at the tip portion of the first and second electrically conductive members  72 , 73 , with which the probe stylus  71  contacts with a pad  5  disposed in the semiconductor device. As a result, the impact at the contact of the probe stylus and the pad disposed in the semiconductor is absorbed by the resilient portion. Therefore, a warp of a probe card, which may be caused by the contact of the probe styluses and the pads, can be avoided.  
         [0175]    According to the fifteenth embodiment, the first electrically conductive member  72  has a round cross section perpendicular to the longitudinal direction. And the diameter of the first electrically conductive members is substantially equal to that of a probe stylus in the prior art. Therefore, a current capacity of an electrically conductive member for forcing at a precise inspection of I/O of a semiconductor device at a wafer state can be assured to be equal to that of probe stylus for forcing in the prior art.  
       SIXTEENTH EMBODIMENT  
       [0176]    In a probe stylus according to the fifteenth embodiment, the first and second electrically conductive members  72 ,  73  are connected to each other. On the other hand, in a probe stylus according to the sixteenth embodiment of the present invention, the first and second electrically conductive member are not connected to each other. And at an inspection of a semiconductor device, they are connected to each other through a pad disposed in a semiconductor device. The other feature is similar to that of the fifteenth embodiment.  
         [0177]    [0177]FIG. 40 shows that the probe stylus is contacting with a pad disposed in a semiconductor device. Referring to the figure, reference numerals  71   c,    72   c ,  73   c  denote a probe stylus, a first electrically conductive member, and a second electrically conductive member, respectively. The first and second electrically conductive members  72   a ,  73   a  are connected by an insulating member  74   c  arranged between them. Reference numeral  5  denotes a pad. disposed in a semiconductor.  
         [0178]    The structure of a probe card having probe stylus  71   c  according to the sixteenth embodiment is similar to that of the probe card shown in FIG. 17. The connection between a probe stylus  71   c  and the substrate of a probe card is similar to that shown in FIGS. 18, 19. The function of the probe stylus and the probe card is similar to that of the second embodiment.  
         [0179]    As explained, the first and second electrically conductive members  72   a ,  73   a  in the probe stylus according to the sixteenth embodiment contact electrically to each other through a pad  5  disposed in a semiconductor at an inspection of a semiconductor device. Therefore, the value of voltage and/or electric current can be compensated up to the pad  5 , at a precise inspection of a semiconductor device at a wafer state. And a line for driver and a line for comparator are assured up to the pad  5 , at an inspection of an I/O of a semiconductor device at a wafer state. As a result, a higher precision inspection of a semiconductor device becomes possible.  
         [0180]    A probe stylus according to the sixteenth embodiment has advantages similar to that of the fifteenth embodiment.  
       SEVENTEENTH EMBODIMENT  
       [0181]    [0181]FIG. 42 shows that the probe stylus is contacting with a pad disposed in a semiconductor device. Referring to the figure, reference numerals  81 ,  82 ,  83  denote a probe stylus, a first electrically conductive member, and a second electrically conductive member, respectively. The first and second electrically conductive members  82 ,  83  are connected by an insulating member  84  arranged between them. Reference numeral  5  denotes a pad disposed in a semiconductor.  
         [0182]    The probe stylus  81  of the seventeenth embodiment of the present invention is a so-called cantilever type probe stylus. The first electrically conductive members  82  has a form of needle. The cross section perpendicular to the longitudinal direction of the needle is round. The second electrically conductive member  83  has a form of cylinder covering the first electrically conductive member  82 . In this embodiment, the first electrically conductive member  82  has a thickness equal to that of a cantilever type probe stylus in the prior art, and the outer side of the first electrically conductive member is covered with an insulating member  84 . Further, the outside of the insulating member  84  is covered with the second electrically conductive member  83 . Thus, the assembly of the probe stylus of the seventeenth embodiment has a thickness substantially equal to a cantilever type probe stylus in the prior art. The first and second electrically conductive members  82 ,  83  are connected to each other at their tip, where the probe stylus contacts with a pad disposed in a semiconductor device.  
         [0183]    The structure of a probe card having probe stylus  81  according to the seventeenth embodiment is similar to that of the probe card shown in FIG. 4. FIG. 44 is a detailed cross sectional view of the connecting portion between the probe card and a probe stylus according to the seventeenth embodiment. FIG. 44 corresponds to FIG. 5. Each element in FIG. 44 corresponding to an element in FIG. 5 and/or  42  is referred by the same reference numeral. The function of the probe stylus and the probe card is similar to that of the first embodiment.  
         [0184]    As explained, the probe stylus  81  according to the seventeenth embodiment of the present invention has a first electrically conductive member  82  and a second electrically conductive member  83 . Therefore, such a probe stylus functions equivalent to two probe styluses in the prior art. As a result, by contacting one probe stylus to each pad disposed in the semiconductor device, it is possible to eliminate so-called dead band in the comparator in a precise inspection of a semiconductor device at a wafer state, or in an inspection of an I/O of a semiconductor device at a wafer state. Also in a case that a large number of pads are disposed in a semiconductor device, corresponding large number of probe styluses can be disposed on a probe card, so that so-called dead band in the comparator can be eliminated in a precise inspection of a semiconductor device at a wafer state, or in an inspection of an I/O of a semiconductor device at a wafer state.  
         [0185]    A probe stylus according to the seventeenth embodiment of the present invention functions equivalently to two probe stylus in the prior art, hence, the number of probe styluses  81  to be attached to a probe card and/or the area required for the arrangement of the probe stylus in a probe card can be reduced, as a result, the fabrication cost can be reduced.  
         [0186]    In this embodiment, the assembly of the probe stylus of the seventeenth embodiment has a thickness substantially equal to a cantilever type probe stylus in the prior art. Therefore, the thickness of the probe stylus  81  according to the seventeenth embodiment is smaller than that of bundled two probe styluses in the prior art. As a result, also in a case that a large number of pads are disposed in a semiconductor device, a corresponding number of the probe styluses  81  can be attached onto a probe card.  
         [0187]    According to the seventeenth embodiment of the present invention, the first electrically conductive members  82  has a round cross section perpendicular to the longitudinal direction. And the diameter of the first electrically conductive members is substantially equal to that of a probe stylus in the prior art. Therefore, a current capacity of an electrically conductive member for forcing can be assured to be equal to that of probe stylus for forcing in the prior art, when the first electrically conductive members  82  is used as an electrically conductive member for forcing at a precise inspection of I/O of a semiconductor device at a wafer state.  
         [0188]    According to the seventeenth embodiment, the first electrically conductive member  82  is covered with an insulating member  84 , and the insulating member  84 , in turn, is covered with the second electrically conductive member  83 . Therefore, when the first electrically conductive member  82  is used for sensing, the electrically conductive member for sensing can be protected from external noises.  
       EIGHTEENTH EMBODIMENT  
       [0189]    In a probe stylus according to the seventeenth embodiment, the first and second electrically conductive members  82 ,  83  are connected at their tip. On the other hand, in a probe stylus according to the eighteenth embodiment of the present invention, the first and second electrically conductive members are not connected at their tip. And at an inspection of a semiconductor device, they are connected to each other through a pad disposed in the semiconductor device. The other feature is similar to that of the seventeenth embodiment.  
         [0190]    [0190]FIG. 45 shows that the probe stylus is contacting with a pad disposed in a semiconductor device. Referring to the figure, reference numerals  81   a,    82   a ,  83   a  denote a probe stylus, a first electrically conductive member, and a second electrically conductive member, respectively. The first and second electrically conductive members  82   a ,  83   a  are connected by an insulating member  84   a  arranged between them. Reference numeral  5  denotes a pad disposed in a semiconductor.  
         [0191]    The structure of a probe card having probe stylus  81   a  according to the eighteenth embodiment is similar to that of the probe card shown in FIG. 4. The connection between a probe stylus  81   a  and the substrate of a probe card is similar to that shown in FIG. 44. The function of the probe card and the probe stylus is similar to that of the second embodiment.  
         [0192]    As explained, the first and second electrically conductive members  82   a ,  83   a  in the probe stylus according to the eighteenth embodiment contact electrically to each other through a pad  5  disposed in the semiconductor at an inspection of a semiconductor device. Therefore, the value of voltage and/or electric current can be compensated up to the pad  5 , at a precise inspection of a semiconductor device at a wafer state. And a line for driver and a line for comparator are assured up to the pad  5 , at an inspection of an I/O of a semiconductor device at a wafer state. As a result, a higher precision inspection of a semiconductor device becomes possible.  
         [0193]    A probe stylus according to the eighteenth embodiment has advantages similar to that of the seventeenth embodiment.  
       NINETEENTH EMBODIMENT  
       [0194]    [0194]FIG. 47 shows that the probe stylus is contacting with a pad disposed in a semiconductor device. Referring to the figure, reference numerals  91 ,  92 ,  93  denote a probe stylus, a first electrically conductive member, and a second electrically conductive member, respectively. The first and second electrically conductive members  92 ,  93  are connected by an insulating member  94  arranged between them. Reference numeral  5  denotes a pad disposed in a semiconductor.  
         [0195]    The probe stylus  91  of the nineteenth embodiment of the present invention is a so-called perpendicular type probe stylus. The first electrically conductive members  92  has a form of needle and its cross section perpendicular to the longitudinal direction of the needle is round. The second electrically conductive member  93  has a form of a cylinder, and covers the first electrically conductive member  92 . In this embodiment, the first electrically conductive member  92  has a thickness substantially equal to that of a perpendicular type probe stylus in the prior art, and the outer side of the first electrically conductive member is covered with an insulating member  94 . Further, the outside of the insulating member  94  is covered with the second electrically conductive member  93 . Thus, the assembly of the probe stylus of the nineteenth embodiment has a thickness substantially equal to a perpendicular type probe stylus in the prior art. The first and second electrically conductive members  92 ,  93  are connected to each other at their tip portion, where the probe stylus contacts with a pad  5  disposed in a semiconductor device.  
         [0196]    The structure of a probe card having probe stylus  91  according to the nineteenth embodiment is similar to that of the probe card shown in FIG. 17.  
         [0197]    [0197]FIG. 49 is a detailed cross sectional view of an example of the connecting portion between the probe card and a substrate of a probe stylus  91  according to the nineteenth embodiment. FIG. 49 corresponds to FIG. 18. In the figure, reference numeral  96  denotes a electrically conductive boss. And reference numeral  97  denotes a spring. The other element corresponding to an element in FIG. 47 is referred by the same reference numeral.  
         [0198]    [0198]FIG. 50 is a detailed cross sectional view of another example of the connecting portion between the probe card and a substrate of a probe stylus  91  according to the nineteenth embodiment. FIG. 50 corresponds to FIG. 19. In the figure, reference numerals  98 ,  99 , and  100  denote a contacter, a electrically conductive bar and an insulating member, respectively. The other element corresponding to an element in FIG. 49 is referred by the same reference numeral. The function of the probe stylus and the probe card is similar to that of the first embodiment. The probe stylus according to the nineteenth embodiment has advantages similar to that of the seventeenth embodiment.  
       TWENTIETH EMBODIMENT  
       [0199]    In a probe stylus according to the nineteenth embodiment, the first and second electrically conductive members  92 ,  93  are connected at their tip. On the other hand, in a probe stylus according to the twentieth embodiment of the present invention, the first and second electrically conductive members are not connected at their tip. And at an inspection of a semiconductor device, they are connected to each other through a pad disposed in the semiconductor device. The other feature is similar to that of the nineteenth embodiment.  
         [0200]    [0200]FIG. 51 shows that the probe stylus is contacting with a pad disposed in a semiconductor device. Referring to the figure, reference numerals  91   a,    92   a ,  93   a  denote a probe stylus, a first electrically conductive member, and a second electrically conductive member, respectively. The first and second electrically conductive members  92   a ,  93   a  are connected by an insulating member  94   a  arranged between them. Reference numeral  5  denotes a pad disposed in a semiconductor.  
         [0201]    The structure of a probe card having probe stylus  91   a  according to the twentieth embodiment is similar to that of the probe card shown in FIG. 17. The connection between a probe stylus  91   a  and the substrate of a probe card is similar to that shown in FIGS. 49 and 50. The function of the probe card and the probe stylus is similar to that of the second embodiment. The probe stylus according to the twentieth embodiment has advantages similar to that of the eighteenth embodiment.  
       TWENTY-FIRST EMBODIMENT  
       [0202]    [0202]FIG. 53 shows that the probe stylus is contacting with a pad disposed in a semiconductor device. Referring to the figure, reference numerals  101 ,  102 ,  103  denote a probe stylus, a first electrically conductive member, and a second electrically conductive member, respectively. The first and second electrically conductive members  102 ,  103  are connected by an insulating member  104  arranged between them. Reference numeral  5  denotes a pad disposed in a semiconductor.  
         [0203]    The probe stylus  101  of the twenty-first embodiment of the present invention is a so-called perpendicular type probe stylus. The first electrically conductive members  102  has a form of needle and its cross section perpendicular to the longitudinal direction of the needle is round. The second electrically conductive member  103  has a form of cylinder, and covers the first electrically conductive member  102 . In this embodiment, the first electrically conductive member  102  has a thickness equal to that of a perpendicular type probe stylus in the prior art, and the outer side of the first electrically conductive member is covered with an insulating member  104 . Further, the outside of the insulating member  104  is covered with the second electrically conductive member  103 . Thus, the assembly of the probe stylus of the twenty-first embodiment has a thickness substantially equal to a perpendicular type probe stylus in the prior art.  
         [0204]    A probe stylus  101  according to the twenty-first embodiment of the present invention has an arc or jack-knifed resilient portion at the tip portion of the first and second electrically conductive members  102 ,  103 , with which the probe stylus  101  contacts with a pad  5  disposed in the semiconductor device. The first and second electrically conductive members  102 ,  103  are connected to each other at their tip, where the probe stylus  101  contacts with a pad  5  disposed in the semiconductor device.  
         [0205]    The structure of a probe card having probe stylus  101  according to the twenty-first embodiment is similar to that of the probe card shown in FIG. 17. The connection between a probe stylus  101  and the substrate of a probe card is similar to that shown in FIGS. 49 and 50. The function of the probe card and the probe stylus is similar to that of the first embodiment.  
         [0206]    In a probe stylus according to the twenty-first embodiment of the present invention, an arc or jack-knifed resilient portion is formed at the tip portion of the first and second electrically conductive members  102 ,  103 , with which the probe stylus contacts with a pad  5 , which is disposed in a semiconductor device. As a result, the impact at the contact of the probe stylus and the pad disposed in the semiconductor is absorbed by the resilient portion. Therefore, a warp of a probe card, which may be caused by the contact of the probe styluses and the pads, can be avoided. The probe stylus according to the twenty-first embodiment has advantages similar to that of the seventeenth embodiment.  
       TWENTY-SECOND EMBODIMENT  
       [0207]    In a probe stylus according to the twenty-first embodiment, the first and second electrically conductive members  102 ,  103  are connected at their tip. On the other hand, in a probe stylus according to the twenty-second embodiment of the present invention, the first and second electrically conductive members are not connected at their tip. And at an inspection of a semiconductor device, they are connected to each other through a pad disposed in a semiconductor device. The other feature is similar to that of the twenty-first embodiment.  
         [0208]    [0208]FIG. 55 shows that the probe stylus is contacting with a pad disposed in a semiconductor device. Referring to the figure, reference numerals  101   a,    102   a ,  103   a  denote a probe stylus, a first electrically conductive member, and a second electrically conductive member, respectively. The first and second electrically conductive members  102   a ,  103   a  are connected by an insulating member  104   a  arranged between them. Reference numeral  5  denotes a pad disposed in a semiconductor.  
         [0209]    The structure of a probe card having probe stylus  101   a  according to the twenty-second embodiment is similar to that of the probe card shown in FIG. 17. The connection between a probe stylus  101   a  and the substrate of a probe card is similar to that shown in FIGS. 49, 50. The function of the probe card and the probe stylus is similar to that of the second embodiment.  
         [0210]    In a probe stylus according to the twenty-second embodiment of the present invention, an arc or jack-knifed resilient portion is formed at the tip portion of the first and second electrically conductive members  102   a ,  103   a,  with which the probe stylus contacts with a pad  5 , which is disposed in a semiconductor device. As a result, the impact at the contact of the probe stylus and the pad disposed in the semiconductor is absorbed by the resilient portion. Therefore, a warp of a probe card, which may be caused by the contact of the probe styluses  101   a  and the pads, can be avoided. The probe stylus according to the twenty-second embodiment has advantages similar to that of the eighteenth embodiment.  
       TWENTY-THIRD EMBODIMENT  
       [0211]    [0211]FIGS. 57, 58 are schematic plan views of a probe stylus according to the twenty-third embodiment. FIG. 57 shows a state that the probe stylus is not contacting with a pad disposed in a semiconductor. And FIG. 58 shows a state that the probe stylus is contacting with a pad disposed in a semiconductor. FIG. 59 is a side view of a probe stylus seen from the side B 1  in FIG. 57. FIG. 60 is a cross sectional view of an example of a probe stylus. FIG. 60( a ) shows a cross section along the line Cl-Cl in FIG. 57. FIG. 60( b ) shows a cross section along the line D 1 -D 1  in FIG. 57. FIG. 61 is a cross sectional view of another example of a probe stylus, which has a form different from that of FIG. 60. FIG. 61( a ) shows a cross section along the line C 1 -C 1  in FIG. 57. FIG. 61( b ) shows a cross section along the line D 1 -D 1  in FIG. 57.  
         [0212]    Referring to the figures, reference numerals  111 ,  112 ,  113  denote a probe stylus, a first electrically conductive member, and a second electrically conductive member, respectively. The first and second electrically conductive members  112 ,  113  are connected by an insulating member  114  arranged between them. Reference numeral  5  denotes a pad disposed in a semiconductor  
         [0213]    A probe stylus according to the twenty third embodiment of the present invention is a so-called perpendicular type probe stylus. The first and second electrically conductive members  112 ,  113  have a form of needle. Their cross section perpendicular to their longitudinal direction are an arc as shown in FIGS.  60 ( a ), ( b ) or a quadrate as shown in FIGS.  61 ( a ), ( b ). The nearer to their tip, where the probe stylus contacts with a pad  5  disposed in a semiconductor device, the thinner their thickness is. According to the twenty-third embodiment, a slit is disposed in the tip portion of the probe stylus, where the probe stylus contacts with a pad disposed in a semiconductor stylus. When the probe stylus does not contact with a pad  5 , the slit closes so that the first and second electrically conductive members  112 ,  113  contact to each other. On the other hand, when the probe stylus contacts with a pad  5 , the slit opens so that the first and second electrically conductive members  112 ,  113  separate from each other.  
         [0214]    The structure of a probe card having probe stylus  111  according to the twenty-third embodiment is similar to that of the probe card shown in FIG. 4. The connection between a probe stylus  111  and the substrate of a probe card is similar to that shown in FIG. 12. The function of the probe card and the probe stylus is similar to that of the second embodiment.  
         [0215]    As explained, the probe stylus  1  according to the twenty-third embodiment of the present invention has a first electrically conductive member  112  and a second electrically conductive member  113 . Therefore, such a probe stylus functions equivalent to two probe styluses in the prior art. As a result, by contacting one probe stylus to each pad disposed in the semiconductor device, it is possible to eliminate so-called dead band in the comparator in a precise inspection of a semiconductor device at a wafer state, or in an inspection of an I/O of a semiconductor device at a wafer state. Also in a case that a large number of pads are disposed in a semiconductor device, corresponding large number of probe styluses can be disposed on a probe card, so that so-called dead band in the comparator can be eliminated in a precise inspection of a semiconductor device at a wafer state, or in an inspection of an I/O of a semiconductor device at a wafer state.  
         [0216]    A probe stylus according to the twenty-third embodiment of the present invention functions equivalently to two probe stylus in the prior art, hence, the number of probe styluses  111  to be attached to a probe card and/or the area required for the arrangement of the probe stylus in a probe card can be reduced, as a result, the fabrication cost can be reduced.  
         [0217]    Because the first and second electrically conductive members  112 ,  113  of the probe stylus according to the twenty-third embodiment are arranged side by side, a force urges them equally, when the probe stylus  111  contacts with a pad  5  disposed in a semiconductor. As a result, the structural reliability of the probe stylus is improved.  
         [0218]    In a probe stylus according to the twenty-third embodiment of the present invention, a slit is disposed between the tip portion of the first and second electrically conductive members  112 , 113 , with which the probe stylus  111  contacts with a pad  5  disposed in the semiconductor device. As a result, the impact at the contact of the probe stylus  111  and the pad  5  disposed in the semiconductor is absorbed by the slit portion. Therefore, a warp of a probe card, which may be caused by the contact of the probe styluses and the pads, can be avoided.  
         [0219]    The first and second electrically conductive members  112 ,  113  in the probe stylus  111  according to the twenty-third embodiment separate from each other, when the probe stylus  111  contacts with a pad  5  disposed in a semiconductor. Therefore, the value of voltage and/or electric current can be compensated up to the pad  5 , at a precise inspection of a semiconductor device at a wafer state. And a line for driver and a line for comparator are assured up to the pad  5 , at an inspection of an I/O of a semiconductor device at a wafer state. As a result, a higher precision inspection of a semiconductor device becomes possible.