Abstract:
A tooling plate for installation into a probe station and being formed of a rigid plate defining a major aperture having a rim. The plate also defines a set of peripheral apertures fitted with spring loaded, retained screws adapted to facilitate fastening to mating threaded holes. In one embodiment, a set of dowel locator holes defined by the bottom surface and being precisely positioned with respect to the location of the major aperture. Another embodiment includes docking equipment adapted to permit connection to a predetermined tester attached to the top of the rigid plate.

Description:
RELATED APPLICATIONS 
   The present application is a divisional of U.S. patent application Ser. No.: 09/662,735; filing date: Sep. 15, 2000 now U.S. Pat. No. 6,408,500. 

   BACKGROUND OF THE INVENTION 
   In the semiconductor field, each set of wafers fabricated is typically performance tested, before they are diced into individual integrated circuits.  FIGS. 1-4  show equipment that is used in this testing. Although these figures show an embodiment of the invention they also show some features that are shared with prior art systems. These features are referenced in this section to help explain the context of the invention. 
   To perform wafer testing a piece of equipment known as a probe station  10  has a head plate  12  that defines an original head plate aperture  14  FIG.  3 . The aperture supports a circular device known as a probe card dish  16 , which in turn supports the probe card  17 . A separate piece of equipment, known as a tester  18  having docking units  20 , is lowered into mating position with respect to the probe station, the probe card dish and the probe card. Sometimes probe station  10  includes an obstacle, such as a wafer loader cover  19 , that is too close to the original head plate aperture  14  to permit the docking of a particular tester  18 . 
   Generally, a number of guides and associated docking equipment pieces are needed to successfully dock a tester to a probe station, a probe card dish and the wafer that the probe card dish supports. Probe stations are generally sold to semiconductor manufacturing facilities with this docking equipment already installed. Accordingly, when a new tester is purchased it is typically necessary to purchase a new probe station fitted with docking equipment to facilitate docking with the new tester. Unfortunately, the docking equipment, which is typically installed by the probe station vendor or a secondary source, generally permits docking to a single make of tester. The installation of docking equipment to permit the use of a different tester with the probe station is referred to in the industry as “hardware swap-out” and results in extensive use of technician time and equipment down time. 
   It is known to machine a single prober to accept a single tooling plate that permits docking to a desired tester. There appears, however, not to have been an effort in the prior art to produce a set of standardized tooling plates that could each be used on any one of a set of differing probe stations. As a result, only very limited flexibility was gained by this method. 
   Another issue facing semiconductor manufacturers is the lack of uniformity of head plate apertures, between the various commercial lines of probe stations. The unfortunate result is that there is currently no known technique for mating a probe station having a first head plate aperture size with a tester designed to mate with a prober having a second head plate aperture size. 
   SUMMARY OF THE INVENTION 
   In a first separate aspect, the present invention is a tooling plate for installation into a probe station. The plate comprises a rigid plate defining a major aperture and a set of peripheral apertures fitted with spring loaded, retained screws adapted to facilitate fastening to mating threaded holes. 
   In a second separate aspect, the present invention is a tooling plate for installation into a probe station, the plate comprising a rigid plate defining a major aperture and a set of dowel locater holes precisely set with respect to the location of the major aperture. 
   In a third separate aspect, the present invention is a tooling plate for installation into a probe station, said tooling plate comprising a rigid plate having a top and a bottom and defining a major aperture having a rim, and having docking equipment adapted to permit connection to a predetermined tester attached to said top of said rigid plate. 
   In a fourth separate aspect, the present invention is a tooling plate for installation into a probe station, said tooling plate comprising a rigid plate defining a major aperture having a rim adapted to retain a probe card dish and a set of bosses protruding slightly upwardly along said rim, each boss fitted with a threaded hole, to facilitate the attachment of said probe card dish. 
   The foregoing and other objectives, features and advantages of the invention will be more readily understood upon consideration of the following detailed description of the preferred embodiment(s), taken in conjunction with the accompanying drawings. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a side view of a probe station-tester mating pair wherein the probe station has been retrofitted according to the method of the present invention. 
       FIG. 2  is a top view of the probe station of FIG.  1 . 
       FIG. 3  is an exploded perspective view of a portion of the probe station of  FIG. 1 , showing some of the details of the retrofitting of the present invention. 
       FIG. 4  is a perspective view of a tooling plate and docking equipment attached to the tooling plate. 
       FIG. 5  is a perspective view of another embodiment of a tooling plate. 
   

   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
   To perform one preferred method of retrofitting a probe station according to the present invention, 0.3 mm (12 mils) of material is machined away from the top of the head plate  12  of the probe station  10  (both items have been introduced in the Background section) to form a head plate-tooling plate attachment region  34  (FIG.  3 ). A pair of through-holes (not shown) is drilled through the attachment region  34  of the head plate  12  to permit the attachment of a pair of dowel pins  38 . 
   In addition a sequence of threaded holes  44  are machined just inside the periphery of attachment region  34 . The method of retrofitting a probe station that is the subject of the present invention is accomplished with the use of a tooling plate  110  as shown in  FIGS. 1 and 2 . Spring-loaded screws are set into a set of apertures  113 , to permit the rapid attachment of plate  110  to a retrofitted probe station. The bottom side of plate  110  defines dowel pin locator holes  120 , which are configured to mate with dowel pins  38  and thereby facilitate the precise positioning of plate  110 . In one preferred embodiment the dowel pins  38  are sited with great precision relative to the center of aperture  14  to ensure correct alignment and positioning of a tooling plate  110 . 
   The tooling plate  110 , defines a tooling plate major aperture  112  for supporting a probe card dish. A rim  122 , adapted for probe card dish attachment is defined about aperture  112 . A set of bosses  124 , each sunk with a threaded hole  126 , ease the attachment of the probe card dish. Referring to  FIG. 4 , in some instances a set of docking equipment  130  is included as a part of an alternative tooling plate  110 ′ so that the installation of plate  110 ′ renders the probe station  10  ready to dock with a tester of choice  18 . 
   Ideally, a number of tooling plates  110 ′ could be provided, each one fitted with a distinct set of docking equipment  130  adapted to dock with a particular tester. In this manner, a semiconductor manufacturing facility that owns a number of testers and a number of probe stations could dock any one of a number of testers with any one of a number of probe stations. Moreover, if more than one probe station was retrofitted to accept any one out of a number of tooling plates  110 ′, than any one of these testers could be placed in service with any probe station for which a matable plate  110 ′ was available. 
   It should be expressly noted that by producing a set of tooling plates, each of which has a standardized set of location and attachment items, and by modifying a set of probe stations so that each one has a standardized set of location and attachment items designed to mate to the tooling plate location and attachment items, that a great flexibility can be achieved in the sense that any of the probe stations can be mated to any of the tooling plates and thereby to any tester for which such a tooling plate is available. This technique appears to be unknown in the prior art and can be applied even to probe stations of differing makes, such as the popular brands TSK®, TEL® and EG®. 
   In an alternative preferred embodiment, no depression is machined in head plate  12 . Dowell pins  38  and threaded holes  44  are provided on the top surface of head plate  12  and a tooling plate  110  is attached on top of head plate  12 . 
   In one preferred embodiment a second set of threaded holes  44 ′ is provided in head plate attachment region  34  for the attachment of a smaller tooling plate  110 . Such a smaller tooling plate  110  would typically be made to fit a probe station  10  having a smaller head plate. By providing the second set of threaded holes  44 ′ a probe station  10  is made available for retrofitting with tooling plates  110  made primarily for a different line of probe stations  10  having smaller head plates  12 . 
   Referring again to  FIGS. 1-2 , in some instances, a probe station will have a head plate that is fairly small and will, further, have an obstacle  19  such as the cover for the device that loads the wafers onto the probe card dish (the “loader cover”). It may not be possible to dock this type of probe station to a tester without moving the probe card dish location away from the obstacle. To do this, the original head plate aperture  14  is enlarged by region  208  (FIG.  3 ), and a tooling plate  210  ( FIG. 5 ) is provided having a major aperture  212  ( FIG. 5 ) that is not centered with respect to the remainder of the tooling plate  210 . When tooling plate  210  is installed the major aperture  212  is located differently from the original head plate major aperture  14  and is further away from the obstacle, thereby permitting a tester of choice to dock to tooling plate  210  without encountering the obstacle. 
   In this embodiment the docking equipment  220  is included on a set of docking equipment plates  222 . To facilitate the correct attachment of plates  222  to head plate  12 , head plate  12  is machined in similar manner to the machining of attachment region  34  but nearer to its edge to form docking equipment plate attachment regions (not shown) which would include location and attachment items such as threaded holes and dowel pins. 
   It should be noted that to successfully implement the embodiment shown in  FIGS. 1 and 2 , that the software that drives the tester and probe station must be adjusted to account for the difference in location between the tooling plate major aperture  212  and head plate original major aperture  14 . 
   The terms and expressions which have been employed in the foregoing specification are used as terms of description and not of limitation, and there is no intention, in the use of such terms and expressions, of excluding equivalents of the features shown and described or portions thereof, it being recognized that the scope of the invention is defined and limited only by the claims which follow.