Patent Publication Number: US-2022214377-A1

Title: Test device

Description:
REFERENCE TO RELATED APPLICATIONS 
     This is a divisional of pending U.S. patent application Ser. No. 16/850,116 filed on Apr. 16, 2020, which is a continuation of International Patent Application PCT/KR2018/014396 filed on Nov. 22, 2018, which designates the United States and claims priority of Korean Patent Application No. 10-2017-0162775 filed on Nov. 30, 2017, the entire contents of which are incorporated herein by reference. 
    
    
     FIELD OF THE INVENTION 
     The present disclosure relates to a test device, and more particularly to a test device for a high-speed and high-frequency test, which effectively blocks out noise from an adjacent signal line and is excellent in signal transmission characteristics. 
     BACKGROUND OF THE INVENTION 
     To test electric characteristics of an object to be tested such as a semiconductor, a test device has employed a probe socket for supporting a test probe, and a test circuit board for contacting the test probe and applying a test signal. As a high-frequency and high-speed semiconductor is decreased in pitch and increased in allowable current, a noise shield between signal probes of the probe socket has become very important. That is, the mechanical length, impedance matching, etc. of the test circuit board have become important as test speed and frequency get higher. 
     A conventional test device includes a probe socket for supporting a signal probe, and a test circuit board placed under the probe socket and providing a test signal. The probe socket performs a test as the signal probe is inserted in a conductive brass block without contact. Further, the test circuit board includes a signal pad and a conductive column formed on an insulating dielectric substrate and transmitting the test signal. When the high-frequency and high-speed semiconductor or the like object that requires high isolation is subjected to the test, a conductive ground body has been used to shield adjacent signal probes of the probe socket from each other. However, for a more reliable test, there is a need of managing an isolation loss caused by noise made between the conductive columns and between the signal pads of the test circuit board. Further, the test circuit board includes a wiring line having a predetermined length, and thus a signal loss is caused corresponding to the length of the wiring line, thereby deteriorating signal transmission characteristics. 
     SUMMARY OF THE INVENTION 
     An aspect of the present disclosure is conceived to solve the conventional problems, and provides a test device which effectively blocks out noise between adjacent signal lines and tests a high-frequency and high-speed semiconductor excellent in transmission characteristics of a test signal. 
     In accordance with an embodiment of the present disclosure, there is provided a test device. The test device includes: a conductive block which includes a probe hole; at least one signal probe which is supported in an inner wall of the probe hole without contact, includes a first end to be in contact with a testing contact point of the object to be tested, and is retractable in a lengthwise direction; and a coaxial cable which includes a core wire to be in electric contact with a second end of the signal probe. Thus, the test device certainly blocks out noise between the signal probes on a cable supporting substrate and enhances the transmission characteristics of the test signal. 
     The test device may further include a cable accommodating hole in which the coaxial cable is accommodated, and a cable supporter which includes a cable supporting block coupled to the conductive block so that the probe hole corresponds to the cable accommodating hole, thereby firmly supporting the coaxial cable. 
     The cable supporting block may include a cable supporting recess for supporting the coaxial cable, thereby preventing the coaxial cable from moving. 
     The cable supporter may include an extended plate portion integrally extended from the cable supporting block, thereby preventing interference between the coaxial cables. 
     The cable supporter may include a cable supporting substrate having a through hole through which the cable supporting block passes, thereby stably fastening the cable supporting block to the conductive block. 
     With this test device, the coaxial cable is in direct contact with the signal probe, thereby fully blocking out noise in a test circuit board. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The above and/or other aspects will become apparent and more readily appreciated from the following description of exemplary embodiments, taken in conjunction with the accompanying drawings, in which: 
         FIG. 1  is an exploded cross-sectional view of a test socket in a test device according to a first embodiment of the present disclosure; 
         FIG. 2  is a plane view of the test device according to the first embodiment of the present disclosure; 
         FIG. 3  is a bottom perspective view of the test device according to the first embodiment of the present disclosure; 
         FIG. 4  is an exploded perspective view of the test device according to the first embodiment of the present disclosure; 
         FIG. 5  is a cross-sectional view of the test device according to the first embodiment of the present disclosure; 
         FIG. 6  is a partial enlarged cross-sectional view illustrating a detailed coupling state between a signal probe and a coaxial cable according to the first embodiment of the present disclosure; and 
         FIG. 7  is a cross-sectional view of a test device according to a second embodiment of the present disclosure. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Below, a test device  1  according to a first embodiment of the present disclosure will be described in detail with reference to the accompanying drawings. 
       FIG. 1  is an exploded cross-sectional view of a test socket in the test device  1  according to a first embodiment of the present disclosure, and  FIGS. 2 to 6  are respectively a plane view, a bottom perspective view, an exploded perspective view, a cross-sectional view and a partial enlarged cross-sectional view of the test device  1  according to the first embodiment of the present disclosure. As shown therein, the test device  1  includes a test socket  100 , a coaxial cable  200 , and a cable supporter  300 . 
     Referring to  FIG. 1 , the test socket  100  includes a conductive block  110  having at least one signal probe hole  112  and at least one ground probe hole  114 ; a signal probe  120  contactless-accommodated in the signal probe hole  112 ; a ground probe  130  contact-accommodated in the ground probe hole  114 ; an upper supporting member  140  for supporting an upper end of the signal probe  120 , and a lower supporting member  150  for supporting a lower end of the signal probe  120 . 
     The conductive block  110  includes an upper supporting member accommodating groove  116  on an upper side to accommodate the upper supporting member  140 . The upper supporting member accommodating groove  116  includes a shield island  117  protruding at the center. The shield island  117  blocks out noise made in the signal probes  120  supported on the non-conductive upper supporting member  140 . The signal probe  120  in the middle passes through the signal probe hole  112  without contact, and is then supported on the upper supporting member  140 . 
     The signal probe  120  has an upper end to be in contact with a testing contact point (not shown) of an object to be tested, and a lower end to be in contact with a core wire  210  of the coaxial cable  200 . The signal probe  120  applies a test signal through the core wire  210  of the coaxial cable  200 . The signal probe  120  may be materialized by a retractable Pogo pin. The signal probe  120  includes a barrel (not shown), upper and lower plungers (not shown) partially inserted in the opposite ends of the barrel, and a spring (not shown) arranged between the upper and lower plungers within the barrel. At least one of the upper and lower plungers is inserted in the barrel and slide to compress the spring within the barrel. 
     The ground probe  130  having an upper end to be in contact with a ground terminal of an object to be tested (not shown), and a lower end to be in contact with the cable supporter  300 . The ground probe  130  receives a ground signal from the object to be tested. The ground probe  130  may be may be materialized by a retractable Pogo pin. The ground probe  130  includes a barrel (not shown), upper and lower plungers (not shown) partially inserted in the opposite ends of the barrel, and a spring (not shown) arranged between the upper and lower plungers within the barrel. At least one of the upper and lower plungers is inserted in the barrel and slide to compress the spring within the barrel. The ground probe  130  is supported being in contact with the conductive block  110 . 
     Referring to  FIG. 1  and  FIG. 2 , the shield island  117  is interposed among three signal probe  120 , and five ground probe  130  are supported being in contact with the shield island  117 . In result, the grounded shield island  117  shields the signal probes  120  from noise. 
     The upper supporting member  140  is fastened to the conductive block  110  by a first screw  142  as accommodated in the upper supporting member accommodating groove  116 , thereby supporting the signal probe  120 . The signal probe  120  is inserted in the signal probe hole  112  of the conductive block  110  without contact as floating to prevent a short-circuit. To this end, the insulating upper supporting member  140  supports the upper end of the signal probe  120 . 
     Similarly, the lower supporting member  150  is made of a conductive material and is accommodated in a lower supporting member accommodating groove  118  to support the lower end of the signal probe  120 . The signal probe  120  is inserted in the signal probe hole  112  of the conductive block  110  without contact as floating to prevent a short-circuit. The lower supporting member  150  includes an insulating signal probe supporting member  152  to support the lower end of the signal probe  120 . In result, the signal probe  120  passes through the conductive block  110  and the lower supporting member  150  without contact, and the opposite ends of the signal probe  120  are supported by the upper supporting member  140  and the signal probe supporting member  152 . 
     The signal probe hole  112  and the ground probe hole  114  are formed penetrating the upper supporting member  140 , the conductive block  110  and the lower supporting member  150 . The signal probe  120  is inserted in the signal probe hole  112  without contact, and the ground probe  130  is inserted in and contacts the ground probe hole  114 . In this case, both ends of each of the signal probe  120  and the ground probe  130  partially protrude from the top and bottom surfaces of the upper supporting member  140  and the conductive block  110 . 
     The coaxial cable  200  includes a core wire  210  placed at the core and transmitting a signal, an external conductor  220  surrounding the outer portion of the core wire  210  as separated from the core wire  210  to block out the noise, and an insulator  230  filled in between the core wire  210  and the external conductor  220 . The core wire  210  of the coaxial cable  200  is grinded for contact with the signal probe  120 . The coaxial cable  200  has a first end contacting the signal probe  120  and supported on a cable supporting block  310  (to be described later), and a second end supported on a cable supporting substrate  320  positioned as separated from the first end. The coaxial cable  200  includes a signal connector  240  to receive a test signal from the outside. The signal connector  240  is mounted to the cable supporting substrate  320 . 
     The cable supporter  300  includes the cable supporting block  310  having a cable accommodating hole  312  for accommodating the coaxial cable  200 , and the cable supporting substrate  320  mounted with the test socket  100 . 
     The cable supporting block  310  includes a plurality of cable accommodating holes  312  at positions corresponding to the signal probe holes  112  of the lower supporting member  150 . The cable supporting block  310  may be made of conductive metal. The cable supporting block  310  is coupled to the conductive block  110  by a second screw  144  as inserted in a through hole  322  of the cable supporting substrate  320 . The cable supporting block  310  includes a cable supporting recess  314  recessed at an opposite side to a portion for contact with the conductive block  110 , and an extended plate portion  316  extended transversely. The coaxial cable  200  is inserted in the cable accommodating hole  312  of the cable supporting recess  314  and locked with adhesive (or glue)  315  filled in the cable supporting recess  314 . The extended plate portion  316  is in contact with a rear side of the cable supporting substrate  320  and supports the cable supporting substrate  320  along with the test socket  100 . 
     The cable supporting substrate  320  includes one side onto which the test socket  100  is mounted, and the rear side to which the second ends of the coaxial cables  200  are separately attached for blocking out the noise. The cable supporting substrate  300  includes the through hole  322  in which the cable supporting block  310  is accommodated while penetrating the cable supporting substrate  300 . 
       FIG. 7  is a cross-sectional view of a test device  2  according to a second embodiment of the present disclosure. In comparison with the test device  1  described with reference to  FIGS. 1 to 6 , like numerals refer to like elements, and only different parts will be described. 
     As shown therein, the test device  2  includes the test socket  100 , the coaxial cable  200 , and the cable supporter  300 . 
     The cable supporter  300  does not include the cable supporting substrate  320  unlike that of the first embodiment, and the signal connector  240  is fastened to the extended plate portion  316  instead of the cable supporting substrate  320 . 
     In the test device according to the present disclosure, the signal probe supported in the conductive block is in direct contact with the core wire of the coaxial cable, thereby certainly blocking out the noise between the signal lines at a side of an test circuit board and improving the transmission characteristics of the test signal. Thus, the test device according to the present disclosure enhances the test reliability at a high-speed/high-frequency test. 
     Although the present disclosure is described through a few exemplary embodiments and drawings, the present invention is not limited to the foregoing exemplary embodiments and it will be appreciated by a person having an ordinary skill in the art that various modifications and changes can be made from these embodiments. 
     Therefore, the scope of the present disclosure has to be defined by not the exemplary embodiments but appended claims and the equivalents.