Abstract:
A vertical probe device includes two guide members arranged in a stack manner and defining therebetween an accommodation chamber, a probe holder plate disposed between the guide members, and a plurality of probes inserted through the guide plates and the probe holder plate in such a manner that the probes are flexible within the accommodation chamber. One of the guide plates has at least one through hole. The probe holder plate is slightly moveable in horizontal and vertical directions but fixable to one of the guide plats under a force applied through the at least one through hole to the probe holder plate while the other of the guide plates is removed, thereby preventing damage of the probes or movement of the probes during a maintenance work.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    1. Field of the Invention 
         [0002]    The present invention relates to a probe device and more particularly, to a vertical probe device, which facilitates the performance of a maintenance work without causing damage to each probe of the probe device. 
         [0003]    2. Description of the Related Art 
         [0004]      FIG. 1  shows a vertical-type probe card  1  according to the prior art. According to this design, a circuit board  10  of the vertical-type probe card  1  has multiple transmission lines  11  electrically connected to a probe set  12 . The probe set  12  comprises an upper guide plate  121 , a lower guide plate  122 , a probe holder plate  123 , and a plurality of probes  120 . The upper guide plate  121 , the lower guide plate  122  and the probe holder plate  123  each have a plurality of probe holes for receiving the probes  120 . During installation, the probe holder plate  123  is held at a predetermined elevation relative to the lower guide plate  122 , and then the probes  120  are respectively inserted through the probe holder plate  123  and the lower guide plate  122 , and then the upper guide plate  121  is covered on the probe holder plate  123  to keep the probes  120  standing. Each of the probes  120  has an upper end protruding over the top side of the upper guide plate  121  and electrically connected to the transmission line  11  or other signal line on the circuit board  10 , and a bottom probe tip protruding over the bottom side of the lower guide plate  122  for probing ICs in a wafer level testing. Because the probe holder plate  123  is provided for holding the probes  120  to be inserted through and aligned with the respective probe holes of the guide plate  121  and  122 , it is designed to have a certain looseness relative to each of the probes  120 . In addition, by means of the structure of a free space defined between the upper guide plate  121  and the lower guide plate  122  for allowing displacement of the body portion of each of the probes  120 , the bottom probe tip of each of the probes  120  can flexibly be adjusted to the same probing plane when all of the probes  120  press on the testing ICs at the same time. As a result, the probe set  12  effectively eliminates the anti-force against from the stressed ICs and prevents damage to any of the probes  120 , and therefore ensures an optimal contact of the vertical probe device  1  with all ICs at the test wafer. 
         [0005]    In actual application, replacement or repair of a maintenance work is necessary for probes of a probe device after a long term test engineering. During a maintenance work of the probe set  12 , the upper guide plate  12  must be taken away and then the damaged or worn probes  120  must be pulled out from the probe holder plate  123  and the lower guide plate  122  for replacement or repair. However, because the probe holder plate  123  is covered by the upper guide plate  121  without fixing to any structures of the probe set  12 , it may be lifted with the upper guide plate  121  by the adhesion force induced by taking away the upper guide plate  12  in the maintenance work. As a result, the relative probes  120  standing on the lifted portion of the probe holder plate  123  are forced to be pulled out from the lower guide plate  122 , thus a rework of inserting those still good probes  120  into the probe holder plate  123  and the lower guide plate  122  will be necessary. Therefore, this design requires much labor and time in maintenance. Further, once the probe holder plate  123  is lifted, the correspondingly lifted probes  120  may somewhat be distorted and/or even damaged, thus the extra cost must be paid. 
         [0006]      FIG. 2  shows a Hybrid-buckling beam probe device  20  constructed according to US patent publication No. 2006/0066328. According to this design, a template  32  provided as the probe holder plate  123  of the aforesaid prior art is adhered to the top side of a raised boss formed above a lower die  28 . Therefore, the template  32  is kept in place during the maintenance engineering to open an upper die to repair or replace the damaged or worn probes  36 . However, because the template  32  is affixed to the lower die  28 , it cannot provide the certain looseness and flexibility to the relative probes  36  as the aforementioned probe holder plate  123  of the vertical probe device  1 . At the moment the probes  36  touch the test devices on a semiconductor wafer, the probes  36  receive a forward stress of the anti-force against from the probing devices with limitation to release out, thereby resulting in high possibility of being damaged and shortening the lifetime of the probes  36 . Therefore, this design of Hybrid-buckling beam probe device is still not satisfactory in function. 
       SUMMARY OF THE INVENTION 
       [0007]    The present invention has been accomplished under the circumstances in view. It is therefore the primary objective of the present invention to provide a vertical probe device, which extends the lifetime of probes in a wafer level test and facilitates the performance of a maintenance work for the probe device. 
         [0008]    To achieve this objective of the present invention, the vertical probe device comprises two guide plates arranged in a stack manner, a probe holder plate and a plurality of probes. The probes are made of an electrically conducting material and are used for probing the electronic devices of circuits of the wafer under test. The guide plates and the probe holder plate have respectively probe holes through which the probes are respectively inserted. One of the guide plates has at least one through hole and the two guide plates define therebetween an accommodation chamber. The probe holder plate is disposed between the two guide plates. The probes are flexible within the accommodation chamber. The probe holder plate is slightly moveable in horizontal and vertical directions but fixable to one of the guide plats under a force applied through the at least one through hole to the probe holder plate while the other of the guide plates is removed. 
     
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0009]    The present invention will become more fully understood from the detailed description given hereinbelow and the accompanying drawings which are given by way of illustration only, and thus are not limitative of the present invention, and wherein: 
           [0010]      FIG. 1  is a schematic sectional view of a vertical probe card according to the prior art; 
           [0011]      FIG. 2  is a sectional view of a vertical probe device according to US patent publication No. 2006/0066328; 
           [0012]      FIG. 3  is an exploded view of a vertical probe device constructed in accordance with a first preferred embodiment of the present invention; 
           [0013]      FIG. 4  is a sectional view of the vertical probe device in accordance with the first preferred embodiment of the present invention; 
           [0014]      FIG. 5  is an exploded view of the first preferred embodiment of the present invention during the assembly process of the vertical probe device; 
           [0015]      FIG. 6  is an exploded view of the first preferred embodiment of the present invention during a maintenance work of the vertical probe device; 
           [0016]      FIG. 7  is a schematic sectional view of a vertical probe device in accordance with a second preferred embodiment of the present invention; 
           [0017]      FIG. 8  is a schematic sectional view of a vertical probe device in accordance with a third preferred embodiment of the present invention, and 
           [0018]      FIG. 9  is a schematic sectional view of a vertical probe device in accordance with a fourth preferred embodiment of the present invention. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0019]    As shown in  FIGS. 3 and 4 , a vertical probe device  3  for testing semiconductor wafers or the like in accordance with a first preferred embodiment of the present invention comprises a first guide plate  30 , a second guide plate  40 , a probe holder plate  50 , and multiple conductive probes  60  for probing contact pads of ICs on a semiconductor wafer. 
         [0020]    The first guide plate  30  and the second guide plate  40  are connected with each other in a stack, each having a plurality of probe holes  31  or  41  for the insertion of the probes  60 . The diameter of the probe holes  31  and  41  is approximately equal to the diameter at each of the two distal ends of each probe  60 . The first guide plate  30  has four through holes  32  and a support  33  downwardly protruding from the bottom of the first guide plate  30  and surrounding the through holes  32 . The second guide plate  40  has two supports  42  and an accommodation open chamber  43 . The two supports  42  protrude over the top surface of the second guide plate  40  at a height smaller than that of the support  33  of the first guide plate  30  and a height difference between the supports  42  and the support  33  is greater than the thickness of the probe holder plate  50 . The supports  42  each have two screw holes  421  corresponding to the through holes  32 . The accommodation open chamber  43  is a recessed space defined between the supports  42 . 
         [0021]    The probe holder plate  50  is made of an insulating material and supported by the supports  42  such that the probe holder plate  50  covers the accommodation open chamber  43 . The probe holder plate  50  has a plurality of probe holes  51  and four screw holes  52 . The probe holes  51  of the probe holder plate  50  respectively correspond to the probe holes  31  and  41  of the first guide plate  30  and the second guide plate  40  for the insertion of the probes  60 . The diameter of the probe holes  51  is approximately equal to the cross section of the body of each probe  60 . The screw holes  52  of the probe holder plate  50  are respectively aligned with the screw holes  421  of the supports  42  of the second guide plate  40  for the insertion of respective fasteners, for example, screws  53  (see  FIG. 5 ). The maximum outer diameter of the screws  53  is smaller than the through holes  32  of the first guide plate  30  so that the screws  53  are passable through the through holes  32  of the first guide plate  30 . 
         [0022]    Referring to  FIG. 5 , in the assembly process of the probe device  3 , four screws  53  are respectively fastened to the screw holes  52  of the probe holder plate  50  and the screw holes  421  of the supports  42  of the second guide plate  40  to affix the probe holder plate  50  to the second guide plate  40 , and then the probes  60  are respectively inserted through the probe holes  51  of the probe holder plate  50  and the probe holes  41  of the second guide plate  40  and kept in vertical. And then, align the probe holes  31  of the first guide plate  30  with the probes  60  respectively such that the probes  60  can be respectively inserted through the probe holes  31  of the first guiding plate  30  and the first guide plate  30  can cover over the probe holder plate  50 . And then, remove the four screws  53  from the probe holder plate  50  and the second guide plate  40  through the through holes  32  of the first guide plate  30 . After the assembly is completed, the probe holder plate  50  is slightly movable horizontally as well as vertically in between the first guide plate  30  and the second guide plate  40 . As shown in  FIG. 4 , the probes  60  are respectively inserted through the three-layer structure of the first guide plate  30 , probe holder plate  50  and second guide plate  40 , and kept in vertical. Further, the height difference between the support  33  of the first guide plate  30  and the supports  42  of the second guide plate  40  provides a space for allowing slight displacement of the probe holder plate  50  horizontally as well as vertically so that the probes  60  are slightly deformable to prevent friction between the probes  60  and the probe holder plate  50  when the probes  60  touch the test devices. 
         [0023]    Referring to  FIG. 6 , when replacing or repairing the probes  60  during a maintenance work, four screws are respectively fastened to the screw holes  52  of the probe holder plate  50  and the screw holes  421  of the supports  42  of the second guide plate  40  through the through holes  32  of the first guide plate  30  to affix the probe holder plate  50  to the second guide plate  40  in advance, and then the first guide plate  30  is removed away without displacement or lift of the probe holder plate  50  and the probes  60 , and then the damaged or worn probes  60  can be replaced or repaired. Therefore, the maintenance work of the probe device  3  is easy and will not cause damage to the probes  60 . 
         [0024]    The measure to affix the probe holder plate  50  to the second guide plate  40  is not limited to the arrangement of the screws  53  and the screw holes  52  and  421 .  FIG. 7  shows a vertical probe device  4  in accordance with a second preferred embodiment of the present invention. According to this embodiment, magnetic members  34  are used to fasten the probe holder plate, referenced by  54 , to the second guide plate, referenced by  44  by means of magnetism. For example, a magnetically inductive device is provided at the bottom side of the probe device  4  to attract the magnetic members  34 , thereby holding down the probe holder plate  54  firmly on the second guide plate  44 . The means of magnetism for fixing the probe holder plate with respect to the second guide plate is not limited to the arrangement of the magnetically inductive device at the bottom side of the vertical probe device, that is, not limited to the direction of induced magnetic-field of the magnetic members. Any of a variety of other measures that cause a magnetic force acting in direction from the probe holder plate  54  toward the second guide plate  44  may be employed to achieve the same effect. During a maintenance work, the magnetic members  34  are respectively inserted into the through holes  32  of the first guide plate  30  and closely attached to the probe holder plate  54  to secure the probe holder plate  54  to the second guide plate  44  firmly in place for allowing removal of the first guide plate  30  without displacing or lifting the probe holder plate  54  and the probes  60 . 
         [0025]      FIG. 8  illustrates a vertical probe device  5  in accordance with a third preferred embodiment of the present invention. According to this embodiment, the probe device  5  comprises a first guide plate  35 , a second guide plate  45 , a probe holder plate  55 , and probes  60 . This third embodiment is substantially similar to the aforesaid first and second embodiments with the exception that the first guide plate  35  eliminates the aforesaid through holes; the second guide plate  45  has through holes  450  cut through the supports thereof. When the probe holder plate  55  is covered on the second guide plate  45 , it blocks the through holes  450 . A vacuum pump or like means may be used to draw air out of the through holes  450 , keeping the through holes  450  in a lower air pressure with respect to the ambient air or even in a vacuum state so that the probe holder plate  55  is firmly secured to the second guide plate  45  for allowing removal of the first guide plate  35  during a maintenance work without displacing or lifting the probe holder plate  55  and the probes  60 . 
         [0026]    Further, the vertical probe device of the present invention is not limited to the structure with the respective supports of the first and second guide plate of the aforesaid embodiments.  FIG. 9  shows a vertical probe device  6  in accordance with a fourth preferred embodiment of the present invention. According to this embodiment, the second guide plate comprises a spacer  70  located below the first guide plate  30 , and a base plate  46  attached to a bottom side of the spacer  70 . The spacer  70  has two supports  71  protruded from the top wall thereof. The supports  71  each have a plurality of screw holes  72  corresponding to the through holes  32  on the first guide plate  30  and the screw holes  52  on the probe holder plate  50 . Thus, the probe holder plate  50  can be affixed to the spacer  70  with screws during a maintenance work. When a different set of probes  60  of a different length is used to fit a different probing application, a different height of spacer  70  may be provided to support the probe holder plate  50  above the base plate  46  at a desired elevation so that the installed probes  60  are kept at the optimal elevation for proving test devices accurately. 
         [0027]    The invention being thus described, it will be obvious that the same may be varied in many ways. Such variations are not to be regarded as a departure from the spirit and scope of the invention, and all such modifications as would be obvious to one skilled in the art are intended to be included within the scope of the following claims.