Abstract:
A lift and rotate assembly for use in a workpiece processing station. The lift and rotate assembly includes a body having a slim profile and pins located on opposite sides for mounting the assembly onto a tool frame. The lift and rotating assembly further includes a rotating mechanism coupling a processing head to the body, and for rotating the process head with respect to the body. The rotating mechanism includes a motor, wherein the motor is located within the processing head and the shaft of the motor is coupled to and rotationally fixed with respect to the body. The lift and rotate assembly further includes a lift mechanism for lifting the process head with respect to the body. A cable assembly within the lift and rotate assembly includes a common cable loop for feeding additional length of cable along both the lift direction and the rotational direction of movement.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This is a divisional application of U.S. patent application Ser. No. 09/351,980, filed Jul. 12, 1999, entitled LIFT AND ROTATE ASSEMBLY FOR USE IN A WORKPIECE PROCESSING STATION AND A METHOD OF ATTACHING THE SAME now U.S. Pat. No. 6,168,695. 
    
    
     STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT 
     Not Applicable 
     BACKGROUND OF THE INVENTION 
     The present invention is directed to an apparatus for processing of semiconductor wafers, and in particular, a lift and rotate assembly for use in a workpiece processing station. 
     During the manufacture of semiconductor integrated circuits and other semiconductor articles from semiconductor wafers, it is often necessary to perform several processing steps in one or more processing stations. In order to more fully automate the process and minimize operator handling, tool architectures have been developed incorporating multiple processing stations and automated means for moving semiconductor wafers from one processing station to the next. 
     When developing a tool architecture one consideration is the overall size of a tool. One reason for this is because the manufacture of semiconductor integrated circuits typically take place in a clean room environment, where the creation and maintenance of clean room space has a relatively higher cost, which is related to the size of the space. As a result, efforts and developments which reduce the overall tool size can have a significant cost benefit. 
     Tool size can often be an important consideration when adding to and/or updating a particular tool in a line. If the size and shape of the new tool is equal to or smaller than the available space or the space created by the removal of the old tool being replaced, the impact on nearby tools is minimized. In contrast, when a new or replacement tool is larger than the available space or the space required by the previous tool, it can potentially require the adjustment and/or relocation of the placement of nearby tools. 
     One reason to update one or more tools in a semiconductor manufacturing line is to make a transition from a smaller to a larger wafer size. The use of larger wafer sizes is desirable because it enables a greater number of devices to be manufactured on each wafer. By producing more devices on each wafer the cost of manufacturing each device can often be reduced. 
     Whereas the present standard wafer size for a majority of semiconductor manufacturing lines is 200 millimeters, there is an increasing trend toward the use of 300 millimeter wafers. Therefore, efforts at minimizing or maintaining tool size, while enabling the tool to handle larger wafer sizes would similarly be beneficial. 
     Another consideration when developing a tool architecture is ease of maintenance. Occasionally individual processing stations or portions thereof, need to be removed for regular cleaning and/or maintenance, or replacement. The easier it is to service the assembly or subassembly requiring maintenance, the less time a tool will be down or out of service. 
     Ease of maintenance becomes especially important when one considers that, as previously noted, semiconductor manufacturing tools are often located in a clean room environment. In clean room environments, personnel are typically required to wear protective clothing including gloves, coats, masks, etc., which can make even routine tasks more cumbersome. Therefore, improvements in accessibility of installed assemblies and/or subassemblies and the ease of installation and/or removal of the same would similarly be beneficial. 
     BRIEF SUMMARY OF THE INVENTION 
     A lift and rotate assembly for use in a workpiece processing station is provided. The lift and rotate assembly comprises a body and a process head for receiving a workpiece. The process head is coupled to the body by a rotating mechanism enabling the process head to rotate with respect to the body. 
     In at least one embodiment, the rotating mechanism includes a motor, wherein the motor is located within the process head. The shaft of the motor is coupled to and rotationally fixed with respect to the body. 
     In at least an other embodiment, the lift and rotate assembly further includes a lift mechanism for lifting the portion of the body coupled to the process head with respect to the other portion of the body, in addition to the rotating mechanism. 
     The lift and rotate assembly further provides for a cable assembly providing at least one of signals, gases, and fluids to the processing head. The cable assembly includes a common cable loop for feeding additional length of cable along both the lift direction of movement by the lift mechanism and the rotational direction of movement by the rotating mechanism. 
     In a further embodiment, the lift and rotate assembly provides for pins adapted for mounting the assembly to an exposed surface of a tool frame. 
    
    
     BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS 
     FIG. 1 illustrates a top plan view of a prior art processing tool. 
     FIG. 2 illustrates an isometric view of a partial processing tool in accordance with the present invention shown with several panels removed. 
     FIG. 3 illustrates an isometric front view of the lift and rotate assembly in accordance with the present invention, showing the process head lifted vertically into a raised position with the process head rotated up into a load position. 
     FIG. 4 illustrates an isometric back view of the lift and rotate assembly illustrated in FIG.  3 . 
     FIG. 5 illustrates an isometric front view of the lift and rotate assembly in accordance with the present invention, showing the process head lowered vertically into a lowered position with the process head rotated down into a processing position. 
     FIG. 6 illustrates an isometric back view of the lift and rotate assembly illustrated in FIG.  5 . 
     FIG. 7 illustrates an isometric view of the lift and rotate assembly mounted to an exposed surface of a processing tool with the side panel removed. 
     FIG. 8 illustrates an isometric view of the socket, saddle, and adjustable surfaces, coupled to an exposed surface of the processing tool, within and against which the pins of the lift and rotate assembly rest. 
     FIG. 9 illustrates the lift and rotate assembly of FIG. 4 with the back covers removed. 
     FIG. 10 illustrates the lift and rotate assembly of FIG. 6 with the back covers removed. 
     FIG. 11 illustrates a side cross sectional view of the lift and rotate assembly rotated down in the processing position. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     FIG. 1 illustrates a top plan view of one example of a prior art processing tool  10 . Specifically, FIG. 1 illustrates a top plan view of the top deck  15  of an LT-210™ processing tool manufactured by Semitool, Inc. The LT-210™ processing tool is a tool architecture designed for processing semiconductor wafers up to 200 millimeters in size. The deck  15  includes openings  20  and  25  within which individual processing stations or components thereof can be received. Openings  20  correspond to openings within which processing chambers/bowls are typically received. Openings  25  correspond to openings within which corresponding lift and rotate mechanisms are typically received. To install a corresponding lift and rotate assembly, the assembly is raised above the opening and a portion of the assembly is inserted into the opening  25 . 
     FIG. 2 illustrates an isometric view of a partial processing tool  100 , in accordance with the present invention. Several of the panels are shown removed, however, a pair of side panels  105  are shown still in place. FIG. 2 further shows several lift and rotate assemblies  200 , which are installed in the partial processing tool  100 . Some of the lift and rotate assemblies  200  are shown without their corresponding process heads  205 . Similar to the processing tool  10  in FIG. 1, the processing tool  100  includes a deck  110  having openings  115  within which processing chambers/bowls  400  (FIG. 7) are typically received. 
     Whereas the lift and rotate assemblies of the prior art processing tool  10  (FIG. 1) have openings  25  in the deck  15  within which the lift and tilt assemblies are received, the preferred embodiment of the present invention includes lift and rotate assemblies  200 , which attach at the back edge  120  of the deck  110 . This enables more room on the deck for accommodating a larger processing chamber/bowl which is capable of handling larger wafer sizes. 
     The lift and rotate assemblies  200  can be used in conjunction with the processing chambers/bowls  400  to provide for processes including plating processes, rinse/dry processes, electroless plating processes, and/or immersion chamber processes. 
     FIGS. 3 and 4 illustrate an isometric view of each of the front and back view of the lift and rotate assembly  200 . The lift and rotate assembly includes a process head  205  and a base  210 . The process head  205  is rotatably coupled to the base by a rotating mechanism more clearly shown in connection with FIG.  11 . The base  210  includes a first portion  215  and a second portion  220 . The second portion  220  is adapted so as to be capable of being lifted with respect to the first portion  215 . Specifically, the process head  205  is coupled to the second portion  220  of the base  210 , so as to move with the second portion  220  as it moves with respect to the first portion  215 . 
     In the preferred embodiment, the process head  205  is shown with a single ring contact  225 , against which a wafer to be processed after being received will be held in place. In at least one preferred embodiment, the ring contact provides power to the wafer. 
     At the side near the bottom of the base  210  is a connection box  230  through which signals, including both communication and power signals, gases, and fluids can be received. In the preferred embodiment, the connection box  230  includes three terminals  235 ,  240  and  245 . Terminal  235  receives electronic signals. Terminal  240  receives plating power. Terminal  245  receives gases for actuating the pneumatics and for a backside nitrogen (N 2 ) purge. 
     The base  210  further includes a pair of pins  250  (one not shown) on each side of the base  210 . The pins  250  are adapted for mounting the lift and rotate assembly to the workpiece processing tool frame  100 , shown in FIG.  2 . 
     FIGS. 5 and 6 illustrate an isometric view of each of the front and back view of the lift and rotate assembly  200  in accordance with the present invention, showing the process head  205  lowered vertically into a lowered position with the process head  205  rotated down into a processing position. Otherwise, the features are very similar to the ones shown in FIGS. 3 and 4. 
     FIG. 7 illustrates an isometric view of the lift and rotate assembly  200  mounted to an exposed surface  125  of a processing tool  100  with the side panel  105 , shown in FIG. 2, removed. On the exposed surface  125  of the processing tool  100  is a socket  130 , a saddle  135 , and a pair of adjustable surfaces  140 . A pair of clips  145  captivates the two top pins  250  with respect to each of the adjustable surfaces  140 . It is noted that the clips can take on a variety of forms. A couple of examples include a screw on clamp or a self retaining spring clip. 
     Processing chambers/bowls  400  are shown extending from openings within the deck  110 . 
     FIG. 8 illustrates an isometric view of the socket  130 , saddle  135 , and adjustable surfaces  140 , coupled to an exposed surface  125  of the processing tool  100 , within and against which the pins  250  of the lift and rotate assembly  200  are adapted to rest. 
     The socket  130  includes a spherical recess  150  for receiving a pin  250 , and has a jack screw  160 , which enables the socket  130  to be adjusted in a direction shown by the arrow labeled X. The saddle  135  includes a cylindrical groove  155  for receiving a pin  250 , and similarly has a jack screw  165 , which enables the saddle  135  to be adjusted in a direction shown by the arrow labeled Z. A pair of jack screws  170  enables the adjustable surfaces  140  to be adjusted in a direction shown by the arrows labeled Y. 
     Initially, when the lift and rotate assembly  200  is being installed, the lower left pin  250  is placed in the spherical groove  150  of the socket  130 . With the lower left pin in place, the lower right pin  250  is then lifted up and over the lip  175  of the saddle  135  and lowered into the cylindrical groove  155 . 
     Aided by the weight of the process head  205 , the center of gravity causes the remaining two upper pins  250  of the lift and rotate assembly  200  to fall in the direction of the process head  205  until it comes into contact with the adjustable surfaces  140 . In order to provide greater stability, the upper pins  250  of the lift and rotate assembly  200  are captivated against the adjustable surfaces  140 . A pair of clips  145  are attached to the adjustable surfaces  140  in holes  180  located at the top of the adjustable surface. When in place, the clips  145  extend over and around the upper pins  250 , as shown in FIG.  7 . 
     The socket  130 , the saddle  135 , and the adjustable surfaces  140  can each be independently adjusted to provide proper alignment with the process chamber/bowl  400 . Adjustment is provided by turning one or more of the jack screws. 
     By attaching the lift and rotate assembly  200  to the exposed surface  125  of processing tool  100  via the pins  250  and corresponding hardware  130 ,  135  and  140 , the lift and rotate assembly  200  can be readily attached and detached from the processing tool  100 . Furthermore, the full surface of the deck  110  can then be used to provide an opening for the processing chamber/bowl  400  thereby maximizing bowl size. 
     Another factor which influences the available space on the deck  110  is the depth D of the base  210 . The depth of the base  210  is affected by the arrangement of the mechanical and electrical components inside the base  210 . 
     FIGS. 9 and 10 illustrate the lift and rotate assembly of FIGS. 4 and 6 with the back covers removed. With the back covers removed, the internal structure of the base  210  of the lift and rotate assembly  200  becomes visible. 
     The preferred embodiment of the lift and rotate assembly  200  includes a lift mechanism  255 . The lift mechanism includes a lift axis motor  260  and a lift actuator  265 , which turns a ball screw  270 . As the ball screw turns, a guide block  275  travels up and down the ball screw. The guide block  275  is coupled to the second portion  220  of the base  210 . Correspondingly, as the guide block  275  travels up and down in response to the turning of the ball screw  270 , the second portion  220  of the base  210  is raised and lowered. 
     A compressed gas spring  280  is coupled between the first portion  215  and the second portion  220  of the base  210 . The gas spring  280  ideally provides a counterbalance force approximately equivalent to the force of gravity being exerted on the process head  205  and related components being similarly raised and lowered. This minimizes the force required by the lift axis motor  260  for raising and lowering the process head  205 . 
     The preferred embodiment further includes a linear encoder  282 , which provides the lift mechanism  255  with absolute coordinates for locating itself 
     Located within the second portion  220  of the base  210  is a rotate axis assembly  285 . The rotate axis assembly includes a sensor  290  and a sensor flag  295  for monitoring the rotational movement of the process head  205 . The rotate axis assembly is coupled to a rotating mechanism  300  (FIG. 11) including a motor  305  (FIG. 11) located in the process head  205 . 
     The shaft  310  of the motor  305  is coupled to and rotationally fixed with respect to the base  210 . By fixing the motor shaft  310 , the motor  305  rotates when activated, correspondingly rotating the process head  205 . This enables the processing head to be rotated, and the bulk of the motor  305  to be located in the processing head  205 . As a result, a base  210  having a reduced depth D is possible. 
     The process head  205  receives at least one of signals, gases, and fluids from the signals, gases, and fluids supplied to the lift and rotate assembly  200  via the connection box  230  and a cable assembly  297 . The cable assembly includes a cable loop  315  for feeding additional length of cable to account for movement by the lift mechanism  255  and the rotating mechanism  300 . In positioning the rotating mechanism  300  and the lift mechanism  255 , the rotating mechanism  300  has been aligned with the lift mechanism  255  so as to provide a common direction of movement. 
     By providing a common direction of movement a single cable loop  315  can provide additional cable length for both the lift direction of movement and the rotational direction of movement, thus eliminating the need for a second cable loop. By eliminating the need for a second cable loop further space is conserved within the base  210  of the lift and rotate assembly  200 . 
     The base  210  further includes circuitry  320  for controlling the functioning of the lift and rotate assembly  200 . 
     By locating the bulk of the rotating mechanism  300  in the process head  205  and eliminating the need for a second cable loop, space is conserved in the base  210  of the lift and rotate assembly  200 . Correspondingly this allows for the depth D of the lift and rotate assembly  200  to be reduced and greater space on the deck  110  of the processing tool  100  to be available for the processing chamber/bowl  400 . 
     FIG. 11 illustrates a side cross sectional view of the lift and rotate assembly rotated down in the processing position. In addition to illustrating the presence of the bulk of the motor for the rotating mechanism  300  in the processing head, FIG. 11 illustrates a second motor  325  adapted for spinning a received workpiece in a plane parallel to the face  330  of the process head  205 . 
     Numerous modifications may be made to the foregoing system without departing from the basic teachings thereof. Although the present invention has been described in substantial detail with reference to one or more specific embodiments, those of skill in the art will recognize that changes may be made thereto without departing from the scope and spirit of the invention as set forth in the appended claims.