Abstract:
A pickup chuck for retaining a semiconductor chip package having electrical contact pads on a surface thereof facing into the pickup chuck. The pickup chuck includes an electrically conductive member for coupling the contact pads to an external electrical device, such as a tester.

Description:
BACKGROUND OF THE INVENTION 
     1). Field of the Invention 
     The present invention relates generally to testing of semiconductor chip packages and, more specifically, to a pickup chuck which is used in combination with a contactor for purposes of testing a semiconductor chip package, and to a method of making electrical contact between a semiconductor chip package and a contactor. 
     2). Discussion of Related Art 
     FIG. 1 of the accompanying drawings shows a conventional semiconductor chip package  10  comprising a package substrate  12  and a semiconductor chip  14  located on the package substrate  12 . An integrated circuit is located within the semiconductor chip  14 . The integrated circuit is placed in electrical communication with the package substrate  12  via an array of solder balls  16 . Electrical leads  18  lead through the package substrate  12  to a set of contact pads  20  on an opposing surface of the package substrate  12 . A semiconductor chip such as the semiconductor chip  14  of FIG. 1 is usually tested after being located on the package substrate  12  and before being shipped out. 
     FIG. 2 illustrates diagramatically a portion of a conventional pickup chuck  26 , for purposes of picking up a semiconductor chip package  10  such as in FIG. 1, defining a recess  28 . The pickup chuck is positioned over the semiconductor chip package  10  with the semiconductor chip package  10  located within the recess  28  and seating on an inner surface  30  of the recess  28 . Suction pads or the like (not shown), are then operated so as to retain the semiconductor chip package  10  within the recess  28 . Utilizing the pickup chuck  26 , the semiconductor chip package  10  is then transported to a contactor which is electrically connected to an electrical test unit. 
     FIG. 3 illustrates the pickup chuck  26  which is used in combination with a contactor  32  for purposes of electrically connecting the contact pads  20  to the electric test unit. The contactor  32  has a locating formation  34  therein which receives the pickup chuck  26 , and a set of pogo pins  36 , located within the locating formation  34 , each of which making contact with a respective contact pad  20 . Electrical leads  38  extend from the pogo pins  36  and eventually end up within the electric test unit. The semiconductor chip  14  is thus electrically connected to the test unit via the array of solder balls  16 , the electric leads  18 , the contact pads  20 , the pogo pins  36 , and the electric leads  38 . Two of the electric leads  38 A and  38 B are respectively connected to a power source and electric ground for purposes of supplying electric power to the semiconductor chip  14  and supplying the semiconductor chip  14  with electric ground. Note that the electric power and electric ground are supplied to the semiconductor chip package  10  via two of the contact pads  20 , all of the contact pads being located on a single surface of the package substrate  12 . 
     FIG. 4 illustrates recent developments in the technology of Intel Corporation of Santa Clara, Calif. wherein electric contacts are provided on opposing surfaces of the package substrate. FIG. 4 shows a semiconductor chip package  50  which includes a package substrate  52  and a semiconductor chip  54  located on the package substrate  52 . Electric connection between an integrated circuit within the semiconductor chip  54  and the package substrate  52  is made via an array of solder balls  56 . The package substrate  52  is made in layers which include a first metal layer  58  and a second metal layer  60 . The first and second metal layers  58  and  60  each has a exposed region at the end of the package substrate  52 . The exposed regions are positioned so as to form a first electric contact  62  on a chip side of the package substrate  52  and a second electric contact  64  on a non-chip side of the package substrate  52 . First and second electric leads  66 A and  66 B connect the semiconductor chip  54  electrically to respectively the first metal layer  58  and the second metal layer  60 . Electric power is supplied to the semiconductor chip  54  by application of a power source to the first electric contact  62 , and electric ground is supplied to the semiconductor chip  54  by application of electric ground to the second electrical contact  64 . More electric leads  68  extend through the package substrate  52  to contact pads  70  on the non-chip side of the package substrate  52 . The contact pads  70  serve to provide logic communication to the semiconductor chip  54 . 
     It can thus be seen that the semiconductor chip package  50  has electric contacts on opposing sides thereof, as opposed to the semiconductor chip package  10  of FIG. 1 which only has electric contact pads on one side thereof. A test arrangement is therefore required which can make contact with all contacts. Although the description that follows is primarily directed at apparatus for purposes of handling the semiconductor chip package  50  of FIG. 4, it should be understood that the invention resides in the broader concept of making electric contact with contacts on opposing sides of a semiconductor chip package, regardless of the exact positioning or purpose of the contacts. 
     SUMMARY OF THE INVENTION 
     The invention provides a pickup chuck which includes a body defining a recess for receiving a semiconductor chip package, and an electrically conductive element mounted within the recess. The electrically conductive element comprises a first portion contacting an electrical contact on the semiconductor chip package facing into the recess, and a second portion extending from the first portion past an edge of the semiconductor chip package in a direction which is out of the recess. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The present invention is illustrated by way of example and not limitation in the figures in the accompanying drawings in which: 
     FIG. 1 is a sectioned side view of a conventional semiconductor chip package; 
     FIG. 2 is a sectioned side view of a conventional pickup chuck which is used for picking up the semiconductor chip package of FIG. 1; 
     FIG. 3 is a sectioned side view of the pickup chuck of FIG. 2 used in combination with a conventional contactor; 
     FIG. 4 is sectioned side view of one semiconductor chip package having contacts on opposing surfaces; 
     FIG. 5 is sectioned side view illustrating a pickup chuck according to one embodiment of the invention; 
     FIG. 6 is a sectioned side view of a contactor and the pickup chuck of FIG. 5 which is used for picking up a semiconductor chip package of the kind shown in FIG. 4; 
     FIG. 7 is a sectioned side view, similar to FIG. 6, illustrating the pickup chuck after engagement with the contactor; 
     FIG. 8 is a sectioned side view of another semiconductor chip package; 
     FIG. 9 is a plan view of the semiconductor chip package of FIG. 8; 
     FIG. 10 is a perspective view from above of a conductive element for purposes of making contact with the semiconductor chip package of FIG. 9; 
     FIG. 11 is a perspective view from below of the element of FIG. 10; and 
     FIG. 12 is a sectioned side view of another contactor and a pickup chuck incorporating the element of FIGS. 10 and 11. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     In the following description, for purposes of explanation, numerous specific details are set forth in order to provide a thorough understanding of the present invention. It will be evident, however, to one skilled in the art that the present invention may be practiced without these specific details. In other instances well known testing methods and apparatuses have not been described in detail in order to not obscure the present invention. 
     FIG. 5 of the accompanying drawings illustrates a pickup chuck  90 , according to the invention, which includes a body  92  defining a recess  94 , an L-shaped electrically conductive element  96  and a suction pad  97  mounted within recess  94 . 
     The element  96  comprises a first portion  98  extending in a direction  100  which is towards a periphery of the recess  94 , and a second portion  102  extending from the first portion  98  in a direction  104  which is outwardly from the recess  94 . The element  96  is mounted to the body  92  by a set of springs  106  which bias the element  96  in a direction  108  which is outwardly from the recess  94 . A capacitor  110  is electrically connected to the first portion  98  and is fixed thereto. 
     FIG. 6 illustrates a tester combination, including the pickup chuck  90  of FIG. 5 and a contactor  116 . 
     The pickup chuck  90  is shown after picking up a semiconductor chip package  50  of the kind shown in FIG. 4 with the suction pad  97  engaging the semiconductor chip package  50 , retaining the semiconductor chip package  50  within the recess  94 . The recess  94  is deep and wide enough to accommodate the semiconductor chip package  50  and is shaped to receive the semiconductor chip package  50  with the first electric contact  62  facing into the recess  94  and touching the first portion  98  of the electrically conductive element  96 . The semiconductor chip package  50  thus seats on an inner surface of the recess  94  and on the first portion  98  of the element  96 . The second portion  102  extends from the first portion  98  past an edge of the semiconductor chip package  50 . An exposed side  118  of the pickup chuck  90  and the semiconductor chip package  50  thus have a number of contacts exposed to the contactor  116 , including the contact pads  70 , the second electrical contact  64 , a contact  119  on the capacitor  110 , and a surface  121  of the second portion  102  of the electrically conductive element  96 . 
     The contactor  116  is formed with a locating formation  126 , a number of pogo pins on a surface within the locating information  126 , and a number of electrical leads connected to the pogo pins, including a power supply lead  128  and an electrical ground lead  130 . A number of the pogo pins  132  are aligned with the contact pads  70 . A pogo pin  134  is aligned with the second electrical contact  64 . A pogo pin  136  is aligned with the contact  119  on the capacitor  110 . A pogo pin  138  is aligned with the surface  121  of the second portion  102  of the electrically conductive element  96 . The pogo pins  132  are connected via electrical leads  140  to an electrical test unit. The pogo pins  134  and  136  are connected to the electric ground  130 . The pogo pin  138  is connected to the power supply  128 . 
     FIG. 7 illustrates the tester combination of FIG. 6 after the pickup chuck  90  is moved towards the contactor  116 ,and until the pickup chuck  90  engages within the locating formation  126 . The movement of the pickup chuck  90  towards the contactor  116  causes the pogo pins  132  to contact the contact pads  70 , the pogo pin  134  to contact the second electrical contact  64 , the pogo pin  136  to contact the contact  119  on the capacitor  110 , and the pogo pin  138  to contact the surface  121  of the second portion  102  of the electrically conductive element  96 . The second electrical contact  64 , and therefore the semiconductor chip  54 , is thus connected to electric ground  130  and the first electric contact  62 , facing into the recess  94 , is connected to the power supply  128  via the electrically conductive element  96 . Electric power and ground is thus established with the semiconductor chip  54 . 
     Positive engagement of the electrically conductive element  96 , the semiconductor chip package  50 , and the pogo pins relatively to one another is allowed for by compression of the springs  106 . 
     It is known than a certain inductance exists between the first electrical contact  62  and the second electrical contact  64 . High inductance is undesirable when alternating power is supplied to the contacts  62  and  64 . The inductance can be reduced by bridging the contacts  62  and  64  with a capacitor. The closer the capacitor is in the electric circuit to the contacts  62  and  64 , the more the inductance will be reduced. For this reason the capacitor  110  is located on the first portion  98 , so as to be as close as possible to the first electric contact  62 , and is connected to the second electric contact  64  via the pogo pins  136  and  134 . By positioning of the capacitor  110  in the position shown, the inductance can generally be reduced to below 0.3 nH. 
     Thus, a tester combination, a pickup chuck, and a method of making electrical contact between a semiconductor chip package and a contactor have been described. Although the present invention has been described with reference to specific exemplary embodiments, it will be evident that various modifications may be made to these embodiments without the departing from the broader spirit and scope of the invention. 
     For example, FIGS. 8 and 9 illustrate another semiconductor chip package  210  and FIGS. 10-12 illustrate apparatus for use in handling the semiconductor chip package  210 . 
     The semiconductor chip package  210  includes a package substrate  212  and a semiconductor chip  214  located on the package substrate  212 . Electric connection between an integrated circuit located in the semiconductor chip  214  and the package substrate  212  is made via an array of solder balls  216 . The package substrate  212  is made in layers which includes a first metal layer  218 , a second metal layer  220 , and a third layer of metal  222 . The first and second metal layers  218  and  220  each has an exposed region at an end of the package substrate  212 . The exposed regions are positioned so as to form a first electric contact  224  on a chip side of the package substrate  212  and a second electric contact  226  on non-chip side of the package substrate  212 . First and second electric leads,  228 A and  228 B respectively, connect the semiconductor chip  214  electrically to respectively the first metal layer  218  and the second metal layer  220 . Electric power is supplied to the semiconductor chip  214  by application of a power source to the first electric contact  224 , and electric ground is supplied to the semiconductor chip  214  by application of electric ground to the second electric contact  226 . More electric leads  230  extend through the package substrate  212  to contact pads  232  on the non-chip side of the package substrate  212 . The contact pads  232  serve to provide logic communication to the semiconductor chip  214 . 
     The third layer of metal  222  is formed in strips which terminate in a set of contact pads  233 A,B,C . . . A number of the solder balls, which in FIG. 8 are located behind or in another, are each connected to a respective strip of the third layer of metal  222  by means of respective electric leads  236 A,B,C . . . Each solder ball can therefore be independently accessed by making contact to a respective contact pad  233 A,B,C . . . of the set of contact pads. The semiconductor chip package  212  thus has more than one electric contact on the chip side thereof, and more electric contacts on the non-chip side thereof. 
     FIGS. 10 and 11 illustrate an electrically conductive element  250  which is used in a pickup chuck  252  which is shown in FIG.  12 . 
     The electrically conductive element  250  comprises a first conductive component  254  and a set of second conductive components  256 A,B,C . . . The first conductive component  254  is in an L shape which extends the entire width of the electrically conductive element  250 . The second conductive components  256 A,B,C . . . each curls around an outer surface of the L shaped first conductive component  254 . The first conductive component  254  is insulated from the second conductive components  256 A,B,C, . . . , and the second conductive components  256 A,B,C . . . are each insulated from one another, by means of insulating material  258 . Referring specifically to FIG. 11, each conductive component  256 A,B,C . . . has terminating contact pads  260 A,B,C . . . and  261 A,B,C . . . respectively on opposing sides of the first conductive component  254 . 
     The pickup chuck  252 , shown in FIG. 12, includes a body  270  defining a recess  272  with the electrically conductive element  250  and a suction pad  251  mounted within the recess  272 . The electrically conductive element  250  is mounted to the body  270  by a set of springs  274  which bias the electrically conductive element  250  in a direction which is outwardly from the recess. The semiconductor chip package  210  is retained within the recess  272  and seats on an inner surface of the recess  272  and on a first portion  282  of the electrically conductive element  250 . The terminating contact pads  261 A,B,C . . . each contacts a respective contact pad  233 A,B,C . . . of the set of contact pads, and the first conductive component  254  contacts the first electric contact  224 . An exposed side  284  of the pickup chuck  252  and the semiconductor chip package  210  thus have a number of contacts exposed, including the terminating contact pads  260 A,B,C . . . , a surface  263  of the first conductive component  254 , the second electric contact  226 , and the contact pads  232 . 
     FIG. 12 also shows a contactor  290  which is used in combination with a pickup chuck  252 . The contactor  290  is formed with a locating formation  292 , a number of pogo pins on the surface within the locating formation  292 , and a number of electrical leads connected to the pogo pins, including a power supply lead  300  and electrical ground lead  302 . A number of the pogo pins  310  are aligned with the contact pads  232 . A pogo pin  312  is aligned with a second electrical contact  226 . A pogo pin  314  is aligned with the surface  26  of the first conductive component  254 . A row of pogo pins  316 A,B,C . . . are aligned with the respective terminating contact pads  260 A,B,C . . . of the second conductive components  256 A,B,C . . . The pogo pin  312  is connected to the electric ground line  302 . The pogo pin  314  is connected to the power supply line  300 . The pogo pins  310  are connected via electrical leads  318  to an electrical test unit. Each of the pogo pins  316 A,B,C . . . is also connected via a respective electrical lead  320 A,B,C . . . to the electrical test unit. The strips of the third layer of metal  222  can thus be individually accessed through the respective electrical leads  320 A,B,C . . . and may, for example, be used to provide logic communication with the semiconductor chip  214 . Such logic communication may, for example, include communication, between the electrical test unit and the semiconductor chip  210 , of the electrical power required by the semiconductor chip  210 . 
     The embodiment of FIGS. 10-12 may be provided with a capacitor, such as in the embodiment of FIGS. 5-7, and other modifications are possible without departing from the broader spirit of the invention. Accordingly, the specification and drawings should be regarded in an illustrative rather than a restrictive sense. 
     Although the two embodiments described above each utilizes an electrically conductive element on the pickup chuck, an embodiment may also be possible wherein the electrically conductive element is located on a contactor, or wherein the electrically conductive element is separate from either a pickup chuck and a contactor. 
     Electric connection in the two embodiments described, is made by movement of the pickup chuck towards the contactor. An embodiment may also be possible wherein electric contact with an electrically conductive element is made following engagement of a pickup chuck with a contactor.