Patent Publication Number: US-2012038383-A1

Title: Direct-docking probing device

Description:
FIELD OF INVENTION 
     The invention relates to a probing device, especially relates to a probing device having a longer service life and a space transforming plate thereof to be less likely to be deformed. 
     BACKGROUND OF THE INVENTION 
     Please refer to  FIG. 1A  and  FIG. 1B .  FIG. 1A  shows a conventional probing system.  FIG. 1B  shows a probing device shown in  FIG. 1A . The probing system  1000  includes a test head  1100 , a conventional probing device  1200 , and a prober  1400 . The probing device  1200  includes a probe interface board  1210 , a pogo tower  1220 , and a probe card  1230 . The probing device  1200  is mounted on the test head  1100 . The test signals sent from the test head  1100  are passed through the probe interface board  1210 , the pogo tower  1220 , and the probe card  1230  in turn, and then transmitted into a device under test (DUT)  1300  via a plurality of vertical probes  1231  of the probe card  1230 . Because the signal transmission path is of a relatively long distance, signal failure is possible to occur when a plurality of high-frequency test signals are transmitted. 
     To try to overcome the above described problems, person skilled in the art had provided another probing system and device. Please refer to  FIG. 2  which shows another conventional probing system. A conventional probing device  10  includes a probe interface board  12 , a space transforming plate  14 , and a vertical probe assembly  19 . The probe interface board  12  is electrically connected with the space transforming plate  14  via a plurality of solders. The vertical probe assembly  19  includes a guide plate  192  and a plurality of vertical probes  194 . The guide plate  192  is mounted on the bottom surface of the space transforming plate  14 . The vertical probes  194  are penetrated through the guide plate  192  and electrically connected with the space transforming plate  14 . 
     The probing device  10  is a direct-docking probing device. No probe card is disposed in the probing device  10 , so that the signal transmission path is shorter and the probing device  10  is suitable for carrying the high-frequency signals. In the probing device  10  (of direct-docking type), the probe interface board  12  is used to replace the circuit board of the probe card. Because the area of the probe interface board  12  is several times larger than that of the circuit board of the probe card, more electronic components can be mounted on the probe interface board  12 . Therefore, the probe interface board  12  has improved test effectiveness and can detect more types of DUTs. In addition, due to having a larger area, the probe interface board  12  can be configured to test a larger number of DUTs at the same time. 
     Whether referring to the probing device  10  in  FIG. 2  or the probing device  1200  in  FIG. 1B , both probing devices  10 ,  1200 , each of which requires to use a seating surface for a flatness standard. The flatness is defined as the difference between the maximum and minimum distances from the tip of the probe to the seating surface. 
     However, the probe interface board  12  and the space transforming plate  14  are connected together by reflowing. During the reflowing operation, the probe interface board  12  must sustain high temperature heating, so that the probe interface board  12  is possible to become damaged. In addition, the unit cost of the probe interface board  12  is higher due to having more electronic components disposed thereon, and the cost burden on the user is thereby increased. 
     In order to try to solve the above described problems, another conventional probing device  20  shown in  FIG. 3  is provided. The probing device  20  includes a probe interface board  22 , a space transforming plate  24 , a fixing frame  25 , a supporting plate  26 , a plurality of electrical contacts  28 , and a vertical probe assembly  29 . The supporting plate  26  is disposed between the probe interface board  22  and the space transforming plate  24 . The electrical contacts  28  are disposed in the supporting plate  26 . The fixing frame  25  is mounted on the probe interface board  22 . The pressing portion  251  of the fixing frame  25  is pressed on the space transforming plate  24 , in order to ensure adequate electrical conductivity between the electrical contacts  28  and the space transforming plate  24 . The electrical contacts  28  and the probe interface board  22  are connected without the reflowing operation, so that the probe interface board  22  does not require sustaining higher temperature heating, and thus the probe interface board  22  has longer service life. 
     In today&#39;s industry; the space transforming plate  24  is made by the back-end-of-line (BEOL) semiconductor manufacturing process, i.e. packaging process, so that the thickness of the space transforming plate  24  has become thinner. However, the height from the bottom surface of the probe interface board  22  to the tip of the vertical probe assembly  29  is limited by the usage environment; thus, such height is harder to be adjusted when the space transforming plate  24  becomes thinner. Taiwan patent publication number 201003078 discloses a thickening plate. The thickening plate, disposed between the electrical contacts and the space transforming plate, can solve the problems caused by the thinner space transforming plate. However, the thickening plate is mainly used in the vertical probe card instead of the direct-docking probing system. 
     Furthermore, the area of the space transforming plate  24  becomes larger due to the corresponding larger area of the probe interface board  22 . Because of the thinner thickness and the larger area of the space transforming plate  24 , the space transforming plate  24  will have larger deformation when the electrical contacts  28  apply an elastic force on it. Therefore, the probes of the vertical probe assembly  29  cannot accurately be contacted with the device under test. In addition, when the vertical probe assembly  29  is contacted with the device under test, the device under test will apply a reaction force back to the vertical probe assembly  29 , so as to deflect the space transforming plate  24  toward the probe interface board  22 , thus compressing and damaging the electrical contacts  28 . 
     Hence, there is a need in the art for preventing the space transforming plate from being deflected in the direct-docking probing device. 
     SUMMARY OF THE INVENTION 
     One aspect of the invention is to provide a direct-docking probing device. The direct-docking probing device can prevent the space transforming plate from being deflected. 
     To achieve the foregoing and other aspects, a direct-docking probing device is provided. The probing device includes a probe interface board, a space transformer, a conductive elastic member, a fixing frame, and at least one vertical probe assembly. The space transformer includes a space transforming plate and a reinforcing plate. The reinforcing plate is disposed between the probe interface board and the space transforming plate, and a plurality of circuits is disposed in the reinforcing plate. The reinforcing plate is electrically connected with the space transforming plate by a plurality of solders. The mechanical strength of the reinforcing plate is larger than that of the space transforming plate. Furthermore, the conductive elastic member is located between the reinforcing plate and the probe interface board, and electrically connected with the probe interface board and the reinforcing plate. The fixing frame includes a stiffener, a frame body, and a pressing portion. The stiffener is disposed on the probe interface board. The frame body contains the conductive elastic member. The pressing portion is pressed on the space transformer. The vertical probe assembly includes a plurality of vertical probes which are electrically connected with the space transforming plate. 
     In the probing device, the pressing portion is pressed on the reinforcing plate. 
     In the probing device, the pressing portion is pressed on the space transforming plate. 
     In the probing device, the reinforcing plate is a multilayer ceramic structure, and the space transforming plate is a multilayer organic structure. The thickness of the space transforming plate is smaller than 1.8 mm and the thickness of the reinforcing plate is larger than 1.0 mm. In addition, the thickness of the space transforming plate is preferably smaller than 1.5 mm and the thickness of the reinforcing plate is preferably larger than 1.5 mm. 
     In the probing device, the solders are surrounded by a filler layer, and the material of the filler layer is a polymer. 
     In the probing device, the Young&#39;s modulus of the space transforming plate is 11 Gpa and the Young&#39;s modulus of the reinforcing plate is 120 Gpa. 
     In the probing device, the conductive elastic member comprises a supporting plate and a plurality of electrical contacts. The electrical contacts are penetrated through and fixed by the supporting plate; and the electrical contacts possess elasticity. 
     In addition, the probing device further comprises a protective device. Compared with respect to the pressing portion of the fixing frame, the protective device is pressed on the other side of the space transformer. 
     In the probing device, the protective device comprises at least two protective spacers. The two ends of the protective spacers are pressed on the probe interface board and the reinforcing plate, respectively. 
     In the probing device, the protective device comprises at least two protective screws. The protective screws are penetrated through the probe interface board, and the bottom ends of the protective screws are pressed on the reinforcing plate. 
     In the probing device, the protective device comprises a limit portion. The limit portion is formed on the frame body and pressed on the reinforcing plate. 
     The protective device comprises a protective frame. The protective frame comprises a hollow portion; and the hollow portion is used for containing the conductive elastic member. The two ends of the protective frame are pressed on the probe interface board and the reinforcing plate, respectively. 
     In the probing device, the protective device is located around the periphery of the conductive elastic member. 
     In the probing device, the electrical circuits in the reinforcing plate are vertically penetrated through the reinforcing plate. 
     In the probing device, the frame body and the pressing portion are formed integrally. 
     The probing device further comprises a protective screw. The protective screw is penetrated through the center portion of the probe interface board and the center portion of the conductive elastic member. The bottom end of the protective screw is pressed on the reinforcing plate. 
     In the probing device, the protective device comprises a protective film, and the conductive elastic member comprises a supporting plate and a plurality of electrical contacts. The electrical contacts are penetrated through the supporting plate and are supported by the supporting plate, and the electrical contacts possess elasticity. The protective film is located between the supporting plate and the reinforcing plate or between the supporting plate and the probe interface board. A plurality of through holes, through which the electrical contacts are penetrated, is formed in the protective film. 
     In the probing device, the quantity of the space transforming plates and the vertical probe assemblies are both numerous, i.e. more than one. Each vertical probe assembly is individually electrically connected to one of the space transforming plates, respectively. 
     Because the mechanical strength of the reinforcing plate is larger than that of the space transforming plate, the amount of deformation of the reinforcing plate is smaller than that of the space transforming plate. Therefore, the offset amount of the vertical probe assembly is small, so that the vertical probes can be more accurately contacted with the device under test. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1A  shows a conventional probing system. 
         FIG. 1B  shows a probing device shown in  FIG. 1A . 
         FIG. 2  shows another conventional probing system. 
         FIG. 3  shows yet another conventional probing system. 
         FIG. 4A  shows a probing system of a first embodiment in the present invention. 
         FIG. 4B  shows a probing device of the first embodiment in the present invention. 
         FIG. 4C  shows a probing device of a second embodiment in the present invention. 
         FIG. 5  shows a probing device of a third embodiment in the present invention. 
         FIG. 6  shows a probing device of a fourth embodiment in the present invention. 
         FIG. 7  shows a probing device of a fifth embodiment in the present invention. 
         FIG. 8  shows a probing device of a sixth embodiment in the present invention. 
         FIG. 9  shows a probing device of a seventh embodiment in the present invention. 
         FIG. 10  shows a probing device of an eighth embodiment in the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Please refer to  FIG. 4A  and  FIG. 4B .  FIG. 4A  shows a probing system of a first embodiment in the present invention.  FIG. 4B  shows a probing device  30  of the first embodiment in the present invention. The probing device  30  is, for example, mounted on the probing system  2000 . The probing system  2000  includes a test head  2100 , the probing device  30 , and a prober  2400 . The prober  2400  includes a wafer stage  2410 . A device under test  2300  is disposed on the wafer stage  2410 . The probing device  30  includes a probe interface board  32 , a space transformer  34 , a fixing frame  35 , a conductive elastic member  36 , two protective spacers  37 , and a vertical probe assembly  39 . 
     Please refer to  FIG. 1A  and  FIG. 4A . In  FIG. 1A  the probe card  1230  of the probing device  1200  is configured to be set downward. The seating surface for the probe card  1230  is formed on the prober  1400 . In  FIG. 4A , the probing device  30  is connected with the test head  2100 . In other words, the probe interface board  32  of the probing device  30  is set in an upward configuration. The seating surface for the probe interface board  32  is formed on the test head  2100 , i.e. the probe interface board  32  is connected with the test head  2100 . 
     Please refer to  FIG. 4B . The space transformer  34  includes a space transforming plate  341  and a reinforcing plate  343 . The reinforcing plate  343  is located between the probe interface board  32  and the space transforming plate  341 . The reinforcing plate  343  is electrically connected with the space transforming plate  341  via a plurality of solders  342 . Furthermore, the mechanical strength of the reinforcing plate  343  is larger than that of the space transforming plate  341 . Because of the presence and usage of the reinforcing plate  343  in the space transformer  34 , the overall mechanical strength of the space transformer  34  is increased. 
     The conductive elastic member  36  is located between the reinforcing plate  343  and the probe interface board  32 . In the embodiment, the conductive elastic member  36  includes a supporting plate  362  and a plurality of electrical contacts  364 . The electrical contacts  364  possess elasticity, and are penetrated through and supported by the supporting plate  362 . Furthermore, a plurality of circuits  3431  is disposed in the reinforcing plate  343 . Therefore, after passing through the electrical contacts  364 , the test signals sent from the probe interface board  32  is then passed through the circuits  3431  in the reinforcing plate  343  and transferred into the space transforming plate  341 . 
     The fixing frame  35  includes a stiffener  352 , a body frame  354 , and a pressing portion  356 . The stiffener  352  is disposed on one side of the probe interface board  32 , and by using two locking screws  353 , the body frame  354  can be screwed on the other side of the probe interface board  32 . The body frame  354  contains the reinforcing plate  343  and the conductive elastic member  36 . The pressing portion  356  is locked on the body frame  354  by the two locking screws  353 . The pressing portion  356  is pressed on one side of the reinforcing plate  343 , in order to ensure adequate electrical conductivity between the electrical contacts  364  and the space transforming plate  343 . Although the body frame  354  and the pressing portion  356  are of two different elements, the body frame  354  and the pressing portion  356  can be formed integrally, so that the locking screws  353  are no longer needed. In addition, the electrical conductivity between the electrical contacts  364  and the reinforcing plate  343  can be enhanced by screwing the locking screws  351  more tightly. 
     Furthermore, the protective spacer  37  is disposed between the reinforcing plate  343  and the probe interface board  32 , and located around the periphery of the conductive elastic member  36 . The two protective spacers  37  are each located on the two opposite sides, respectively. The top ends of the protective spacers  37  are pressed against the probe interface board  32  and the bottom ends of the protective spacers  37  are pressed on the reinforcing plate  343 . Compared with respect to the pressing portion  356 , the protective spacers  37  are pressed on the other side of the reinforcing plate  343 . 
     Please refer to  FIG. 4A . The vertical probe assembly  39  includes a plurality of vertical probes  394 . The vertical probes  394  are electrically connected with the space transforming plate  341 . The bottom of the vertical probes  394  are contacted with the device under test (not shown). 
     In the embodiment, the Young&#39;s module of the space transforming plate  341  is 11 Gpa, and the Young&#39;s module of the reinforcing plate  343  is 120 Gpa. Because the mechanical strength of the reinforcing plate  343  is larger than that of the space transforming plate  341 , the amount of deformation of the space transforming plate  341  is smaller than that of the space transforming plate  24  in  FIG. 3 . Therefore, compared to the vertical probe assembly  29  in  FIG. 3 , the offset amount of the vertical probe assembly  39  is smaller, so that the vertical probes  394  can be more accurately contacted with the device under test (not shown). 
     In addition, when the vertical probe  394  is contacted with the device under test, the device under test will apply a reaction force back to the vertical probe  394 . At the same time, because of the support of the protective spacer  37 , the space transformer  34  is not easily deflected toward the probe interface board  32 . Thus, the electrical contacts  364  are not easily compressed and are thereby better protected. 
     In the embodiment, the reinforcing plate  343  is a multilayer ceramic structure, and the space transforming plate  341  is a multilayer organic structure. Person of ordinary skill in the art can modify the material and the structure of the reinforcing plate  343  or the space transforming plate  341 , provided that the mechanical strength of the reinforcing plate  343  is larger than that of the space transforming plate  341 , so as to prevent any large amount of deformation from occurring on the space transforming plate  341 . The reinforcing plate  343  can also be made as a multilayer organic structure, a printed circuit board structure, or a FR-4 type glass fiber board. 
     In this embodiment, the thickness of the space transforming plate  341  is smaller than 1.8 mm, and the thickness of the reinforcing plate  343  is larger than 1.0 mm. In a preferred embodiment, the thickness of the space transforming plate  341  is smaller than 1.5 mm, and the thickness of the reinforcing plate  343  is larger than 1.5 mm. 
     Please refer to  FIG. 4C  which shows a probing device  30 ′ of a second embodiment in the present invention. In the probing device  30 ′, the solders  342  are surrounded by a filler layer  344 , and the filler layer  344  is made of polymer material. The filler layer  344  is used to prevent the solders  342  from being polluted by the external environment. Because the other elements of the probing device  30 ′ is identical or similar to the elements shown in FIG.  4 B, they are marked with the same numbers in  FIG. 4C  and not described in detail. 
     Person of ordinary skill in the art can use other protective device to replace the protective spacer  37 , for example: a protective frame. The protective frame is a hollow plate-shaped object and is located around the conductive elastic member  36 . The hollow portion of the protective frame is used to contain the conductive elastic member  36 . The two ends of the protective frame are pressed on the probe interface board  32  and the reinforcing plate  343 , respectively. 
     Please refer to  FIG. 5  which shows a probing device  40  of a third embodiment in the present invention. The probing device  40  includes two protective screws  47 . The protective screws  47  are penetrated through the probe interface board  32 , and the bottom ends of the protective screws  47  are pressed on the reinforcing plate  343 . The protective screws  47  and the protective spacer  37  have a similar function, i.e. preventing the space transformer  34  from being deflected toward the probe interface board  32 , so as to avoid the electrical contacts  364  being compressed and damaged. 
     Please refer to  FIG. 6  which shows a probing device  50  of a fourth embodiment in the present invention. In the probing device  50 , a limit portion  3541 ′ is formed on the body frame  354 ′ of the fixing frame  35 ′. Compared with respect to the pressing portion  356 , the limit portion  3541 ′ is pressed on the other side of the reinforcing plate  343 . In other words, the reinforcing plate  343  is clamped by the pressing portion  356  and the limit portion  3541 ′. Because of the limit portion  3541 ′, the deformation of the space transformer  34  caused by the reaction force from the device under test can be avoided. In addition, the limit portion  3541 ′ can prevent the transformer  34  from being deflected toward the probe interface board  32  and protect the electrical contacts  364  from being compressed and damaged, so that the limit portion  3541 ′ can be a protective device for the probing device  50 . 
     Please refer to  FIG. 7  which shows a probing device  60  of a fifth embodiment in the present invention. The probing device  60  includes a protective screw  67 . The protective screw  67  is penetrated through the center portion of a probe interface board  62  and the center portion of a supporting plate  662  of the conductive elastic member  66 . The bottom end of the protective screw  67  is pressed on the reinforcing plate  643 . In another embodiment, a threaded hole (not shown) can be formed in the reinforcing plate  643 , and the bottom end of the protective screw  67  can be screwed with the threaded hole. If the reinforcing plate  643  is made of ceramic material and not easily to be threaded, a metal block having an inner thread can be embedded in the reinforcing plate  643 , so as to lock the bottom end of the protective screw  67  and the reinforcing plate  643  together. When the vertical probe  394  is contacted with the device under test, the device under test will apply a reaction force back. At this time, because the bottom end of the protective screw  67  is pressed on the reinforcing plate  643 , the deflection of a space transformer  64  toward the probe interface board  62  can be avoided. 
     In  FIG. 4A , the circuits  3431  is penetrated through the reinforcing plate  343  vertically. However, in the probing device  60  shown in  FIG. 7 , the protective screw  67  is penetrated through the central portion of the conductive elastic member  66 , so that the electrical contacts  664  would be configured to be disposed in locations toward the respective two sides. Therefore, the circuits  6431  in the reinforcing plate  643  have a deflecting part, in order to ensure adequate electrical connection between the space transformer  64  and the reinforcing plate  643 . Furthermore, in order to better protect the electrical contacts  664 , other protective devices, such as the protective device shown in  FIG. 4A˜FIG   6 , can be disposed around the conductive elastic member  66  shown in  FIG. 7 . 
     Please refer to  FIG. 8  which shows a probing device  70  of a sixth embodiment in the present invention. In this embodiment, the protective device of the probing device  70  includes two protective films  77 . One of the protective films  77  is disposed between the supporting plate  362  and the reinforcing plate  343 , and another protective film  77  is disposed between the supporting plate  362  and the probe interface board  32 . The protective film  77  has a plurality of through holes  771  and the electrical contacts  364  are penetrated through the through holes  771 . Person of ordinary skill in the art can also choose to dispose only one protective film  77  in the probing device  70 , and the protective film  77  is disposed between the supporting plate  362  and the reinforcing plate  343  or between the supporting plate  362  and the probe interface board  32 . 
     In the above described embodiments, the reinforcing plate  343  is disposed in the fixing frame  35 , and the space transforming plate  341  is disposed outside of the fixing frame  35 . Please refer to  FIG. 9 , which shows a probing device  80  of a seventh embodiment in the present invention. In the probing device  80 , a reinforcing plate  343 ′ of a space transformer  34 ′ and a space transforming plate  341 ′ are both disposed in the frame body  354  of the fixing frame  35 . Furthermore, the pressing portion  356  of the fixing frame  35  is pressed on the space transforming plate  341 ′. 
     Please refer to  FIG. 10 , which shows a probing device  90  of an eighth embodiment in the present invention. In the probing device  90 , two space transforming plates  941  are disposed, and two vertical probe assemblies  994  are each mounted on the bottom ends of the two space transforming plates  941 , respectively. Thus the probing device  90  can probe two devices under test at the same time. The surfaces of the probe interface board  32  and the reinforcing plate  343  can be enlarged depending on the requirement conditions, therefore more space transforming plates and vertical probe assemblies can be mounted thereon, so as to probe more than one device under test at the same time. 
     In all of the embodiments discussed above, the electrical contacts are used to electrically connect the reinforcing plate and the probe interface board, and prevent the probe interface board from being processed under the reflow operation, so as to increase the service life of the probe interface board. The electrical contacts can be designed to be in the form such as the signal contacts shown in FIG. 1 and FIG. 2 of U.S. Pat. No. 6,722,893, the electrical contacts shown in FIG. 3 and FIG. 4 of U.S. Pat. No. 6,846,184, or the elastomeric contacts shown in FIG. 1 and FIG. 2 of U.S. Pat. No. 6,712,620. The electrical contacts can be mainly comprised of the anisotropic conductive paste. 
     In the above described embodiments, the probing devices are all equipped with the protective devices. However, Person of ordinary skill in the art can opt to design a probing device having no protective device. 
     Although the description above contains many specifics, these are merely provided to illustrate the invention and should not be construed as limitations of the invention&#39;s scope. Thus it will be apparent to those skilled, in the art that various modifications and variations can be made in the system and processes of the present invention without departing from the spirit or scope of the invention.