Abstract:
An electrical connecting device and related method of testing a semiconductor device which provides testing of a semiconductor device under excellent and stable current transfer characteristics. Moreover, the electrical connecting device is easily produced under mass production conditions and can be made with a structure for testing of a semiconductor device where there are many pins arranged in a fine pitch on the semiconductor device. The electrical connector device includes a contactor which has a coil-shaped spring and a transformable conductive member extending in the compressing direction of the coil-shaped spring. When one end of the conductive member is in contact with a first electrode and the other end of the conductive members in contact with the second electrode, the contactor electrically connects between the first electrode and the second electrode via the conductive member and generates contact pressure against the electrodes when the coil-shaped spring is pressed. A guide plate is provided in the electrical connector device having a through hole for inserting and positioning the contactor therein. In a preferred embodiment, the semiconductor device to be tested has the first electrode for contact against one end of the conductive member of the contactor. The second electrode is a land pattern in a substrate of the electrical connecting device contacting the other end of the transformable conductive member, with the land pattern in turn being connected to testing equipment for testing of the semiconductor device.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a divisional of application Ser. No. 09/104,332, filed Jun. 25, 1998, now U.S. Pat. No. 6,033,233. 
    
    
     This application is based upon and claims priority of Japanese Patent Application No. 09-329106, filed Nov. 28, 1997, the contents being incorporated herein by reference. 
     BACKGROUND OF THE INVENTION 
     The present invention generally relates to an electrical connecting mechanism for a semiconductor device and other electrical elements and more particularly to a connecting device for electrical connection to an IC package in which many pins are arranged with a fine pitch, or a high speed, high frequency IC, such as a bare chip, wafer or other electrical element. 
     A contactor, such as a probe pin, has generally been used as a device for electrical connection to a semiconductor device and other electrical elements, particularly for testing purposes. 
     FIG. 1 is a diagram showing a structure of a probe pin in the related art. The probe pin shown in FIG. 1 includes a metal tube or pipe  200 , a coil-shape spring  201 , a metal end piece  202  and a terminal portion  203 . The coil-shape spring  201  is provided within the metal pipe  200  and the metal end piece  202  is spring-biased in the upward direction of the drawing by the spring force of the coil-shape spring  201 . The metal end piece  202  is provided to establish an electrical connection with an external electrode of a semiconductor device as the object of the test and the spring force produces a contact pressure between the metal end piece  202  and the external electrode. The terminal portion  203  is connected to testing equipment for testing the semiconductor device. 
     In the probe pin shown in FIG. 1, when the metal end piece  202  is in contact with an external electrode of the semiconductor device, a current flows to the terminal portion  203  via the metal tube or pipe  200  from the metal end piece  202 . Therefore, the probe pin itself must be formed in a fine structure in order to provide many of these pins arranged to correspond with an IC package with many external electrodes arranged in a fine pitch. However, since the probe pin has a comparatively complicated structure, it is difficult to manufacture a fine probe pin. Moreover, even if such a fine probe is formed, it becomes very expensive. 
     Therefore, a probe pin as shown in FIG. 2 tends to be used recently. The probe pin of FIG. 2 includes a guide plate  210 , a plurality of holes  211  provided in the guide plate  210  and a plurality of coil-shape springs  212  inserted into the holes  211 . One end of the coil-shape spring  212  to be used as a contactor is placed in contact with an external electrode of a semiconductor device, while the other end of the spring  212  is connected to a testing apparatus. This type of probe pin is formed in a simplified structure and therefore many coil-shape springs  212  can be arranged with a fine pitch. 
     In the probe pin having the structure shown in FIG. 2, a current is transferred via the coil-shape spring  212 . If a certain turn of the coil-shape spring  212  is not kept in contact with the next single turn, a current is transferred through a spiral path of metal wire of the coil-shape spring. Therefore, a problem arises that resistance and inductance become large. 
     In the case of the structure of the probe pin shown in FIG. 2 where a certain turn of the coil-shape spring  212  is in contact with the next single turn in many areas, resistance and inductance can be lowered. However, in this case, when the coil-shape spring  212  is compressed by a contact pressure from the external electrode, the contact condition of a certain turn and the next single turn changes, thereby resulting in a delicate change of a current transfer route. Therefore, a problem arises that fluctuation is generated in the current transfer characteristic in the contact condition. 
     BRIEF SUMMARY OF THE INVENTION 
     It is therefore an object of the present invention to provide an electrical connecting device having an excellent and stable current transfer characteristic. 
     It is a further object of the present invention to provide an electrical connecting device that has a simplified structure, that can be readily mass-produced, and that can be arranged in a fine pitch. 
     It is a further object of the present invention to provide a method of testing a semiconductor device under a condition of an excellent and stable current transfer characteristic. 
     Objects of the invention are achieved by an electrical connecting device comprising a contactor to electrically connect first and second electrodes and having a coil-shape spring, and a transformable conductive member extending in a compressing direction of the coil-shape spring, wherein one end of the conductive member is pressure contactable with the first electrode and the other end of the conductive member is pressure contactable with the second electrode to electrically connect the first and second electrodes when the coil-shape spring is compressed; and a guide plate having a through hole in which the contactor is positioned. 
     A current transfer path may be shortened and low resistance, low inductance and stable electrical transfer characteristic may be realized, and a contact pressure may also be generated with a coil-shape spring by establishing the electrical connection between the first electrode and second electrode via the conductive member in place of the coil-shape spring. Moreover, for electrical connection to a semiconductor device where many pins are arranged with a fine pitch, it can be realized easily that the electrical connecting device can have a plurality of through holes in the guide plate provided with a fine pitch and a plurality of corresponding contactors can be inserted thereto and thereby a low price and high performance electrical connecting device can be provided. 
     Further objects of the invention are achieved by a method of testing a semiconductor device comprising: loading a semiconductor device having a first electrode to an electrical connecting device, the electrical connecting device having a contactor with a coil-shape spring, a transformable conductive member extending in a compressing direction of the coil-shape spring, wherein one end of the conductive member is in contact with the first electrode of the semiconductor device and the other end of the conductive member is in contact with a second electrode to electrically connect the first electrode and the second electrodes when the coil-shape spring is compressed, and a guide plate having a through hole in which the contactor is positioned; connecting test equipment to the second electrode of the electrical connecting device; executing a test to the semiconductor device through the second electrode; and removing the semiconductor device from the electrical connecting device. 
     Since the stable and excellent electrical transfer characteristic can be provided via the conductive member, high precision testing of semiconductor devices can be achieved and deterioration of an electrical signal for testing can be prevented. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     These and other objects and advantages of the invention will become apparent and more readily appreciated from the following description of the preferred embodiments, taken in conjunction with the accompanying drawings of which: 
     FIG. 1 is a diagram showing a structure of a probe pin in the related art. 
     FIG. 2 is a diagram showing another structure of a probe pin in the related art. 
     FIGS. 3A and 3B are diagrams showing a contactor for an electrical connecting device according to a preferred embodiment of the present invention. 
     FIGS. 4A,  4 B,  4 C,  4 D,  4 E, and  4 F, are diagrams showing further modified contactors for an electrical connecting device according to preferred embodiments of the present invention. 
     FIGS. 5A and 5B are diagrams showing an electrical connecting device according to a preferred embodiment of the present invention. 
     FIG. 6 is a diagram showing an electrical connecting device according to another preferred embodiment of the present invention. 
     FIG. 7 is a diagram showing an electrical connecting device according to another preferred embodiment of the present invention. 
     FIG. 8 is a diagram showing an electrical connecting device according to another preferred embodiment of the present invention. 
     FIGS. 9A and 9B are diagrams showing further modified contactors for an electrical connecting device according to a preferred embodiment of the present invention. 
     FIG. 10 is a diagram showing a connection profile for an electrical connecting device using the contactor of the type shown in FIG.  9 A and FIG.  9 B. 
     FIGS. 11A-11D are diagrams showing a method of manufacturing a contactor shown in FIG. 3A according to a preferred embodiment of the invention. 
     FIG. 12 is a diagram showing a structure for a semiconductor device test system using the electrical connecting device according to a preferred embodiment of the present invention. 
     FIGS. 13A-13C are diagrams showing a method for testing a semiconductor device according to a preferred embodiment of the invention. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Reference will now be made in detail to the preferred embodiments of the present invention, examples of which are illustrated in the accompanying drawings, wherein like reference numerals refer to like elements throughout. 
     In accordance with a preferred embodiment of the invention, and as shown in FIGS. 3A and 3B, there is provided an electrical connecting device having a contactor  10 . Contactor  10  of FIG. 3A includes an easily transformable, elongated conductive member  11  and a coil-shape spring  12 . The conductive member  11  is provided within the coil-shape spring  12  along the longitudinal direction thereof and, for example, is formed of a metal wire to transfer current. At both ends of the conductive member  11 , metal balls  11   a  or other similar disc-like contact elements are provided. The coil-shape spring  12  is compressed, as shown in FIG. 3B, when the metal ball  11   a  is in contact with an external electrode such as that of a semiconductor to provide a contact pressure. In this case when the spring  12  is compressed, the conductive member  11  deforms as shown in FIG.  3 B. 
     The metal ball  11   a  has a diameter preferentially larger than the internal diameter of the coil-shape spring  12 . In this manner, the conductive member  11  is never or not allowed to be removed from the coil-shape spring  12 . Even when the coil-shape spring  12  is formed of a conductive material, current is transferred along the shortest route through the conductive member  11 . Therefore, the coil-shape spring  12  may be formed of either a conductive material or a non-conductive material. 
     As explained, in the contactor for the electrical connecting device according to the preferred embodiment of the present invention, the coil-shape spring  12  provides elasticity to generate a contact pressure, while the transformable conductive member  11  provides a current transfer route. Since the route of the conductive member  11  is short, and in particular shorter than through the coil-shape spring, an excellent current transfer characteristic is realized resulting in small inductance and resistance. Moreover, since the current transfer route does not change even during contact with the external electrode, a stable current transfer characteristic also may be realized. 
     FIG. 4A to FIG. 4F show modifications to the contactor for the electrical connecting device in accordance with preferred embodiments of the present invention. In the contactor  10 A of FIG. 4A, both ends of the conductive member  11 A are welded to the coil-shape spring  12 . In the contactor  10 B of FIG. 12B, both ends of the conductive member  11 B are fixedly hooked to the coil-shape spring  12 . In the contactor  10 C of FIG. 4C, a plurality of conductive members  11 C are provided and both ends thereof are welded to the coil-shape spring  12 . In the contactor  10 D of FIG. 4D, the conductive member  11 D is provided on the outside or at the external side of the coil-shape spring  12  and both ends thereof are welded to the coil-shape spring  12 . In the contactor  10 E of FIG. 4E, the conductive member  11 E is arranged on the outside of the coil-shape spring  12  and both ends thereof are fixedly hooked to the coil-shape spring  12 . In the contactor  10 F of FIG. 4F, a plurality of conductive members  11 F are arranged on the outside of the coil-shape spring  12  and both ends thereof are welded to the coil-shape spring  12 . 
     The modified contactors of FIGS. 4A-4F operate and can achieve the same or similar functions as the contactor shown in FIGS. 3A and 3B and as described earlier. Particularly, for the contactors shown in FIG. 4C or FIG. 4F, when a plurality of conductive members are provided, resistance and inductance of the current transfer route may further be reduced in comparison with the case where only one conductive member is provided. 
     An electrical connecting device is shown in FIGS. 5A and 5B and now will be described hereafter in accordance with a preferred embodiment of the invention. 
     As shown in FIG. 5A, electrical connecting device  18  includes contactors  10 , a guide plate  20 , screws  22 , screw stoppers  23  and a substrate  24 . The guide plate  20  is provided with a plurality of holes  21  corresponding to the positions of the external electrodes  31  of a semiconductor device  30  and contactors  10  are positioned in the corresponding holes  21 . Land patterns  25  are formed on one side of the substrate  24  to correspond with the holes  21  and contactors  10  located therein as shown in FIG.  5 B. The guide plate  20  is fixed to the substrate  24  with the screws  22  and screw stoppers  23 . Where the electrical connecting device  18  is applied to an IC package, the pitch of the electrical connecting device  18  can be 2.54 mm to as little as 0.5 mm in a particularly fine pitch, and the quantity of contactors accordingly could be from 10 to as many as 1,000. Where the electrical connecting device  18  is applied to a bare chip, the pitch of the electrical connecting device  18  can be 0.3 mm to as little as 0.04 mm in a particularly fine pitch, and the quantity of contactors accordingly could be a few to as many as a few thousands. 
     FIG. 5B is an enlarged view of portion “A” for the electrical connecting device shown in FIG.  5 A. As shown in FIG. 5B, the contactors  10  are arranged within the holes  21  of the guide plate  20  so that these contactors  10  are in contact with corresponding land patterns  25 . As embodied herein, hole  21  has an inwardly tapered internal wall where the internal diameter of the center area of the hole, for example, is narrowed as shown in FIG.  5 B. Accordingly, the contactor  10  is prevented to be removed from the hole  21 . The land pattern  25  is provided with a wiring  26  for connection with test equipment  49 . 
     The electrical connecting device according to the preferred embodiment of the present invention can be electrically connected stably to the external electrode  31  of the semiconductor device  30  and the semiconductor device  30  can be tested easily by the test equipment  49 . Moreover, since the structure of the contactors  10  and guide plate  20  is comparatively simple, it may be divided easily into small sections and it can be used with a semiconductor device  30  where a plurality of external electrodes  31  are arranged in a fine pitch. 
     An electrical connecting device  18 A according to another preferred embodiment of the present invention is shown in FIG.  6  and will now be described. In FIG. 6, the elements like those elements for the device in FIGS. 5A and 5B are designated by like reference numerals and the same explanation is not repeated herein. 
     In the embodiment of the electrical connecting device  18 A of FIG. 6, a contactor  10 G is used in place of the contactor  10 . In the embodiment of the device shown in FIG. 6, reliability of the electrical connection can be improved by mechanical coupling between the contactor  10 G and land pattern  25 . The contactor  10 G is coupled to the land pattern  25  at the end part of the contactor using a metal coupling means. Such a metal coupling means, for example, could be a metal ball or disc-like element  11   b  fused using solder and fixedly coupled to the land pattern  25 . As another example, a wire bonding technique can be applied. First, a ball at an end of a wire which is through a capillary is made using a hydrogen torch or electrical spark method. Next, the ball is secured at the land pattern  25  by mechanical pressure from the capillary and after the securing step, the wire is cut with appropriate length. Next, a coil-shape spring is provided around the remaining wire on the land pattern  25 . Finally, a metal ball  11   a  is made using a hydrogen torch or electrical spark method. However, the metal coupling means need not be so limited to these examples. 
     An electrical connecting device  18 B according to another preferred embodiment of the present invention is shown in FIG.  7  and will no be described. In FIG. 7, the elements like those elements for the device in FIGS. 5A and 5B are designated by like reference numerals and the same explanation is not repeated here. 
     In the embodiment of the electrical connecting device  18 B in FIG. 7, two guide plates  20 A and  20 B having a plurality of corresponding holes  27  are stacked together. The corresponding holes  27  of the two guide plates have stepped portions  27   a  facing each other where the guide plates join together. Within the space formed by the stepped portion  27   a  of the guide plate  20 A and the respective stepped portion  27   a  of the guide plate  20 B, contactors  10 H having connecting parts  11   c  connected in series are fitted therein. This arrangement prevents the contactor  10 H from being removed from its respective hole  27 . 
     An electrical connecting device  18 C according another embodiment of the present invention is shown in FIG.  8  and will now be described below. In FIG. 8, the elements like those elements for the device in FIG. 7 are designated by like reference numerals and the same explanation is not repeated here. 
     In the embodiment of the electrical connecting device  18 C of FIG. 8, two guide plates  20 A and  20 B having a plurality of corresponding holes  27  are again stacked together. The corresponding holes  27  of the two guide plates have stepped portions  27   a  facing each other where the guide plates join together. Within the space formed by the stepped portion  27   a  of the guide plate  20 A and the stepped portion  27   a  of the guide plate  20 B, a relaying member  13  is fitted therein. Contactors  10 I have connecting parts  11   c  connected in series through the relaying member  13 . This structure prevents the contactors  10 I from being removed from the holes. The method of securing between the metal ball of the contactor  10 I and land pattern  25  or relaying member  13  is the same as the securing method for the embodiment of FIG.  6 . 
     A contactor  10 J and  10 K having a modified structure for the electrical connecting device is shown in FIG.  9 A and FIG. 9B according to another preferred embodiment of the present invention. In FIG.  9 A and FIG. 9B, the elements of this contactor  10 J and  10 K that are like those elements of the contactor  10  in FIG.  3 A and FIG. 3B are designated by like reference numerals and the same explanation is not repeated herein. 
     Contactor  10 J of FIG. 9A includes a conductive member  11 , a coil-shape spring  12  and a metal end piece  14  connected to both ends of the conductive member  11  for contact. As shown in FIG. 9A, the metal end piece  14  for contact has a recess  14   a  and reliable electrical connection can be established by fitting a ball type external electrode of a Ball-Grid-Array (“BGA”) type semiconductor device into the recess  14   a.    
     The further modified contactor  10 K of FIG. 9B includes a conductive member  11 , a coil-shape spring  12  and a metal end piece  15  connected to both ends of the conductive member  11  for contact. As shown in FIG. 9B, the metal end piece  15  for contact has a sharp end point  15   a  and reliable electrical connection can be established by pushing the end point  15   a  to a pin type external electrode of a Quadrille-Flat-Package (“QFP”) type semiconductor device and to the electrode like the land pattern  25  of the substrate  24  for the device of FIG.  5 B. 
     In the contactors shown FIG.  9 A and FIG. 9B, as explained above, reliable electrical connection can be established by providing the metal end piece for contact suitable for the shape of the electrode to be connected. It is not required to provide a metal end piece for contact having the same shape at both ends of the contactor. For example, the metal end piece  14  for contact in the contactor of FIG. 9A can be provided at one end and the metal end piece  15  for contact in the contactor of FIG. 9B can be provided at the other end. 
     FIG. 10 is a schematic view showing a connection for an electrical connecting device using a contactor having metal end pieces of the types shown in FIG.  9 A and FIG.  9 B. In FIG. 10, the elements for the device like those in FIG.  5 A and FIG. 5B, and FIG.  9 A and FIG. 9B are designated by like reference numerals and the same explanation is not repeated here. 
     In this electrical connecting device  18 D of FIG. 10, contactors  10 L have the metal end piece  14  for contact provided at one end and the metal end piece  15  for contact at the other end. Moreover, the recess  14   a  of the metal end piece  14  for contact and the sharp end point or end part  15   a  of the metal end piece  15  for contact are respectively provided with a metal plating  16  of Au to improve the electrical connection. 
     The ball-type external electrode  31  of the semiconductor device  30  is positioned into the recess  14   a  of the metal end piece  14  for contact, while the end part  15   a  of the metal end piece  15  for contact is pushed into contact with the land pattern  15  of the substrate  24 . Thereby, reliable electrical connection can be established between the ball type external electrode  31  of the semiconductor device  30  and the land pattern  25 . 
     A method for manufacturing a contactor for an electrical connecting device in accordance with a preferred embodiment of the invention is shown in FIGS. 11A-11D and will now be described below. 
     As shown in FIG. 11A, in making the contactor  10  a wire  42  is fed from a wire reel  40  and is then inserted into the inside portion of the coil-shape spring  12  which is fixed to a clamping jig  41 . FIG. 11B shows the condition in the subsequent step where the wire  42  is inserted into the coil-shape spring  12 . In this condition and in the next step shown in FIG. 11C, the wire  42  is thermally cut at both ends of the coil-shape spring  12 , for example, by a hydrogen torch method. The wire  42  also may be thermally cut, for example, by an electrical discharging process. When the wire  42  is thermally cut, and as shown in the subsequent step of FIG. 11D, the wire  42  is hardened in the form of a sphere at the cutting end, to provide the conductive member  11  inserted into the coil-shape spring  12  and with metal balls or similar disc-like elements  11  a at both ends of the conductive member  11 . 
     As explained above, the contactor and the other components for the electrical connecting device according to preferred embodiments of the present invention may be produced easily by simple processes which are quite suitable for mass-production. 
     As will now be described and as illustrated in FIG. 12, there is provided an arrangement for semiconductor device test equipment utilizing the electrical connecting device according to embodiments of the present invention. 
     The semiconductor device test equipment shown in FIG. 12 includes a tester  50 , a test head  51 , a wiring  52  connecting the test head  51  and tester  50  and a contactor  53  using the electrical connecting device according to an embodiment of the present invention provided at the test head  51 . An LSI  60  is fitted to the contactor  53  to test the LSI  60 , for example a BGA type LSI, with the tester  50 . The semiconductor device test equipment of FIG. 12 is available in the related art, except for use of the electrical connecting device of the present invention, for example, the embodiment of the device shown in FIG.  5 A. Therefore, a detailed explanation thereof is omitted herein. 
     A method for testing a semiconductor device utilizing the semiconductor device test equipment in FIG. 12 now be described in accordance with a preferred embodiment of the invention. The semiconductor testing method is also illustrated in FIGS. 13A through 13C. 
     In FIG.  13 A through FIG. 13C, the elements of the electrical connecting device used in this testing method that are like those elements of the electrical connecting device in FIG.  5 A and FIG. 5B are designated by like reference numerals and the same explanation is not repeated here. 
     As shown in FIG. 13A, this testing method uses a contactor  53  which includes a guide plate  20  arranging contactors  10  corresponding to an arrangement of external electrodes  61  of LSI  60 . The electrical connection between the external electrode  61  and contactor  10  is established by inserting the LSI  60  into the contactor  53 . FIG. 13B shows the condition or subsequent step where the LSI  60  is inserted into the contactor  53 . Under this condition, various electrical tests are executed on LSI  60  using the appropriate test equipment. After the test, in the next step, the LSI  60  is removed from the contactor  43  as shown in FIG.  13 C. 
     As explained above, this method of testing a semiconductor device can be executed under a stable and excellent electrical connecting condition, while the semiconductor device is loaded or unloaded easily. These advantages of conducting the semiconductor device test according to the processes shown in FIG.  13 A through FIG. 13C are achievable by using the semiconductor test system shown in FIG. 12 provided with an electrical connecting device according to the present invention. 
     Although a few preferred embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that changes may be made in these embodiments without departing from the principles and spirit of the invention, the scope of which is defined in the claims and their equivalents.