Abstract:
An apparatus for quickly and reliably aligning a semiconductor handling apparatus with a semiconductor tester. Two docking plates are attached, one to the device handler and one to the device tester. On the docking plates a substructure is mounted which first allows initial alignment of the handler plate with the test head plate after which the substructure provides the means of securely positioning and interlocking the handler plate with the test head.

Description:
FIELD OF THE INVENTION 
     The invention relates to the field of semiconductor processing, and more specifically to docking and undocking of an electronic test head with a device handler. 
     DESCRIPTION OF THE PRIOR ART 
     In the automatic testing of integrated circuits (IC) and other electronic devices, special device handlers have been used which place the device to be tested in position. The electronic testing itself is provided by a large and sophisticated automatic testing system that includes a test head. The test head is required to connect to and dock with the device handler. In such testing systems, the test head is usually very heavy. The reason for this heaviness is that the test head uses high-speed electronic timing signals. The electronic test circuits must therefore be located as close as possible to the device under test. Accordingly, the test head has been densely packaged with electronic circuits in order to achieve the high speed testing of the state of the art devices. 
     The state of the art left much to be desired in providing a manipulator or positioner to easily move the heavy test head accurately in position with respect to the device handler mechanism. The user has had to move the heavy device handler or the heavy positioner itself in order to provide alignment. When the test head is accurately in position with respect to the device handler, the test head and the device handler are said to be aligned. When the test head and the device handler are aligned, the fragile test head and the device handler electrical connections can be brought together (that is docked) enabling the transfer of test signals between the test head and the device handler. Prior to docking, the test head and the device handler electrical connections must be precisely aligned to avoid damaging the electrical connectors. 
     In a typical electrical test environment, the test head is manually guided to connect delicate electrical pins to the contacting plate of the device handler without alignment guides after which the test head is locked or kept level by means of a device manipulator. This often presents problems during production testing. For instance, the test head can drop in position and loose the electrical connections with the device handler. Or the device handler vibrates causing intermittent electrical connections with the device test head or even causing damage to the electrical equipment. 
     U.S. Pat. No. 5,440,943 (Holt et al) shows a positioner that facilitates docking and undocking of an electronic test head with a device handler. 
     U.S. Pat. No. 5,149,029 (Smith) discloses a system for positioning an electronic test head with respect to an electronic device handler. 
     U.S. Pat. No. 5,450,766 (Holt) shows a test head manipulator for positioning a test head with respect to a device handler. 
     U.S. Pat. No. 5,608,334 (Holt) shows a device testing system. 
     U.S. Pat. No. 4,527,942 (Smith) shows an electronic test head positioner for test systems. 
     U.S. Pat. No. 4,588,346 (Smith) shows a method for positioning an electronic test head. 
     SUMMARY OF THE INVENTION 
     The present invention addresses the problems of quickly and reliably positioning and interlocking a device handler head with respect to a device tester head. 
     The primary objective of the present invention is to provide an apparatus for establishing quick and reliable connections between the semiconductor device handler and the semiconductor device tester. 
     Another objective of the present invention is to reduce the negative effect on device yield caused by unreliable device handler to device tester connection. 
     Yet another objective of the present invention is to reduce the need for device re-testing due to unreliable testing results caused by unreliable device handler to device tester connections (re-screen downtimes). 
     Yet another objective of the present invention is to reduce the downtime required for changing equipment set-up within the semiconductor testing and manufacturing environments. 
     Yet another objective of the present invention is to facilitate the required equipment conversions between different device testing set-up configurations; such that the testhead can be docked securely to the device handler on either 0-degree, 90-degree, or 180-degree positions; such that the device testhead can be docked securely to the device handler on either single-site, double-site or three-site contacts; and such that the device testhead can be docked securely to the device handler on a multiplicity of, different thicknesses of the electronic contactors. 
     The present invention teaches a system for positioning an electronic test head with respect to an electronic device handler. This system comprises two interface plates and an arrangement of mounting brackets to connect the interface plates to the device handler and the device tester respectively. The present invention addresses the problem of quickly and reliably positioning a device handler plate with respect to a device test head plate. The device handler plate is used in moving the semiconductor device between positions, the device test head plate is used when testing the semiconductor device. The present invention relieves problems of questionable yield fallout, excessive downtime for re-testing and equipment set-up. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 shows device handler  1 , the UDS handler plate  2 , the Universal Docking System (UDS) test head plate  3 , the device test head  4 , and the device prober or tester  5 . 
     FIG. 2 shows the UDS handler plate  2 . 
     FIG. 3 shows the prober plate  51 ; this plate is not shown in FIG.  1 . 
     FIG. 4 shows the head plate  61  with mounting taps  62  and alignment holes  63 ; this plate is not shown in FIG.  1 . 
     FIG. 5 shows the test device head plate  70  with UDS alignment cam  71  and UDS alignment pin  72 . Four UDS alignment cams  71  and four UDS alignment pins are mounted on the test device head plate  70 , only one set has been highlighted with numbers in FIG.  5 . 
     FIG. 6 shows one corner of the testhead plate with one UDS cam  71  and one alignment pin  72 . 
     FIG. 7 shows a docking square. 
     FIG. 8 shows a docking triangle. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     It must be pointed out that, for clearness of overview of FIG. 1, the following two units of the tester  5  are not shown in FIG.  1 : the prober plate  51  (see FIG. 3) that is attached to top of the device prober  5  and the complete head plate  61  (see FIG. 4) that interfaces (for alignment purposes) between the device prober  5  and the device prober plate  51 . These two units will be highlighted in subsequent figures. 
     Referring now specifically to FIG.1, shown in FIG. 1 is the relative positioning of the device handler  1 , the device tester  5 , the device test head  4 , and the two UDS device plates, that is the UDS device handler plate  2  and the UDS device test head plate  3 . The UDS device handler plate  2  together with the UDS device test head plate  3  form a mechanical system which aligns, connects and disconnects with respect to each other by means of four pairs of interlocking mechanical sub-assemblies. The UDS handler plate  2  is attached to the device handler  1 , the UDS test head plate  3  is attached to the device test head  4 . The UDS handler plate  2  together with the UDS test head plate  3  form the Universal Docking System (UDS) of the invention. The UDS serves as the mechanism for aligning, connecting and disconnecting the two systems with which they interface. In FIG. 1 these two systems are the device handler and the device tester. 
     FIG. 2 shows the UDS device handler plate  20  in more detail. In a typical application, the UDS device handler plate  20  is an 8 mm. thick aluminum plate that is 876×876 mm. in size. The dimensions for this plate are however not limited to the typical dimensions indicated, the present invention is not limited to these dimensions. The center  21  of the UDS device handler plate  20  is cut out so as not to interfere with any electrical or mechanical components of the test head. On each of the four corners  22  of the UDS device handler plate  20  are mounted an alignment socket  31  and a cam bearing  32 . The UDS device handler plate  20  (FIG. 2) is mounted against the device handler  7  (FIG. 7) using extension brackets (not shown in FIG. 2) which are attached to the sides and the bottom base plate of the device handler. Threads are tapped into the handler plate  22  for screws to fasten the brackets. 
     The above indicated brackets provide the means for mounting the device handler plate onto the device handler. FIG. 2 also shows details of the alignment socket  31  and the cam bearing  32 . The alignment socket  31  is, during the alignment of the UDS device handler plate  2  (FIG. 1) with the device test head plate  3  (FIG.  1 ), brought into contact with and guides an alignment pin. This action positions the UDS handler plate  2  (FIG. 1) in the correct position with respect to the UDS device test head plate  3  (FIG.  1 ). 
     FIG. 2 also shows the UDS handler plate  20  with adjustment slot guides  41  and side adjustment locations  42 . For conversions of the tester where testing is required on more than a central site, such as second or third site testing, the slot guides  41  are used in conjunction with a suspend screw (not shown) attached to the device handler  1  to shift the UDS device handler plate  2  into the second or third test position. The site adjustments  42  have the same function in adjusting the UDS handler plate  2  (FIG. 1) to positions other than the central test position with respect to the test head  4  (FIG.  1 ). 
     FIG. 2 shows on the device handler plate  20  a total of four corners  22  with, on each corner  22 , mounted one alignment socket  31  with, for each alignment socket  31 , a set of two cam bearings  32 . 
     FIG. 3 shows the prober plate  51  that has the same function as the UDS handler plate  2 . However, the thickness of the prober plate  51  is typically 12 mm., this to compensate for the amount of materials which has to be removed so as not to interfere with mechanical or electrical components of the test head  4  (FIG.  1 ). The prober plate  51  is mounted on the head plate of the overhead device prober or tester  5 . 
     FIG. 4 shows the complete test head plate  61  with mounting taps  62  and alignment holes  63 . These positioners are used for positioning the prober plate  61  with respect to the prober equipment  5  when attaching the prober plate  61  to this equipment. 
     The combination of the head plate (FIG. 4) and the prober plate (FIG. 3) provide the mechanical means for mounting the test head plate  3 , FIG. 1, to the tester  5 , FIG. 1, and the device handler  1 , FIG. 1, that is plate  51 , FIG. 3, and plate  61 , FIG. 4, form the mechanical interfaces for mounting the UDS of the invention between the device handler  1 , FIG. 1, and the device tester  5 , FIG.  1 . 
     FIG. 5 shows the test head plate  70 , this assembly has three main bar members which are mounted in a U-Shape structure. The U-bar mounts around the test head using brackets. 
     FIG. 5 shows, on the head test plate  70 , a total of four alignment cams  71  and four alignment pins  72 . These four units  71 / 72  each align with one of the four units  31 / 32  on the corners of the device handler plate  20 , FIG. 2, as previously highlighted under FIG.  2 . The number of matching units  31 / 32  with  71 / 72  is not restricted to four but can be any number of units, such as three, that can establish stability and firm connectivity between the device handler plate  2  (FIG. 1) and the device test head plate  3  (FIG.  1 ). 
     FIG. 6 shows a perspective view of one of the corners of the test plate  70 . Shown in detail is the UDS alignment cam  71  with the UDS alignment pin  72 . 
     During alignment of the device handler  1  (FIG. 1) with the test head  4  (FIG.  1 ), the UDS handler plate  2  (FIG. 1) is visually brought into close physical contact with the UDS test head plate  3 . The alignment pin  72 , FIG. 5, is positioned in line with the matching alignment socket  31 , FIG.  2 . The UDS device alignment cam  71 , FIG. 5, is then manually rotated while final alignment of the UDS device alignment pin  72  with the alignment socket  31  is observed and assured. During the alignment of UDS alignment pin  72  with the UDS alignment socket  31 , the UDS alignment cam  71  starts to touch or engage the UDS alignment cam bearing  32 . Once that contact has been established and the diagonal cut of the UDS alignment cam  71  touches the UDS alignment cam bearing  32 , the cam  71  can be further manually rotated. This final rotation forces the alignment pin  72  into the alignment socket  31 ; the rotation of the cam  71  is supported by the rotation of the cam bearings  32 . After the alignment pin  72  is firmly seated in the alignment socket  31 , the alignment cam  71  is locked in place. 
     The UDS handler plate  2  (FIG. 1) is now securely locked into place with respect to the UDS test head plate  3 . The contact between the handler and the tester is furthermore assured and firm due to the firmness of the UDS constructs. 
     Basic geometry teaches that three points fixed in space define a plane. It is therefore apparent that, in order to accomplish the alignment of one plane with another, such as the UDS handler plate  2  with the UDS test head plate  3 , three points of suspension suffice for each of these two plates. This leads to the concept of three point docking plates, this as opposed to the for point docking system as highlighted in FIGS. 2 and 5 where the UDS handler plate  20  and the UDS test head plate  70  are detailed. FIGS. 7 and 8 highlight the concept of the three point docking system. 
     Referring specifically to FIG. 7, the three points  2 ,  3 , and  4  form the basic or typically used docking points. These three points provide docking possibility of 0-degrees, 90-degrees and 180-degrees docking rotation. Point  1  within FIG. 7 allows for an alternate docking point and can be used in combination with a selection or two points from the three point set  2 ,  3 , and  4 . This selection is completely equipment design and configuration dependent while it provides an additional degree of freedom in the use of the UDS docking system of the present invention. 
     Referring specifically to FIG. 8, the three point docking configuration shown herein by points  1 ,  2 , and  3  provides less freedom in the possible docking configurations since this configuration limits the docking to one configuration. This limitation is however not to be considered a drawback or limitation of the present invention since there are conditions of device testing where this configuration, by means of its very simplicity, can be a configuration of choice most notably where considerations of high device throughput, speed of test set up, etc. are of importance. 
     Although the present invention is illustrated and described herein as embodied in a handler to tester interface which comprises two interface plates and interface positioning substructures, it is nevertheless not intended to be limited to the details as presented. Rather, various modifications may be made in the details within the scope and range of equivalents of the claims and without departing from the spirit of the invention.