Abstract:
A substrate support that aligns a substrate placed thereon is generally provided. In one aspect, a substrate support for supporting a substrate includes a support plate, an alignment member and a cylindrical member. The alignment member is disposed proximate a first edge of the support plate while the cylindrical member is disposed proximate an adjacent, second edge of the support plate. The alignment member extends above the support plate and is adapted to urge the substrate in a first direction. The cylindrical member has a rotational axis aligned with the first direction. In another aspect of the invention, a load lock chamber is provided that includes a chamber body having a first and a second substrate transfer ports. A support plate is disposed in the chamber body and has a substrate alignment mechanism interacting therewith that aligns the substrate on the support plate.

Description:
CROSS REFERENCE TO OTHER RELATED APPLICATIONS  
       [0001]    This application is related to U.S. patent application Ser. No. ______, filed Feb. 22, 2002 (Attorney Docket No. 6885/AKT/DISLAY/BG), entitled “SUBSTRATE SUPPORT”, which is hereby incorporated by reference in its entirety. 
     
    
     
       FIELD OF THE INVENTION  
         [0002]    Embodiments of the invention generally relate to a substrate alignment apparatus.  
         BACKGROUND OF THE INVENTION  
         [0003]    Thin film transistors (TFTs) are conventionally made on large glass substrates or plates for use in monitors, flat panel displays, solar cells, personal digital assistants (PDAs), cell phones and the like. TFTs are made in a cluster tool by sequential deposition of various films including amorphous silicon, doped and undoped silicon oxides, silicon nitride and the like in a plurality of vacuum process chambers typically arranged around a central transfer chamber. The cluster tool is typically coupled to a factory interface that includes a plurality of substrate storage cassette that holds substrates before and after processing. A load lock chamber is generally disposed between the factory interface and cluster tool to facilitate substrate transfer between a vacuum environment of the cluster tool and an atmospheric environment of a factory interface.  
           [0004]    The positioning of glass substrates used for displays in a load lock chamber is difficult as compared to smaller, 200 mm and even 300 mm circular substrates. For example, as glass substrates often have dimensions exceeding 550 mm by 650 mm, with trends towards 1.2 square meters and larger, small deviations in position may result in significant substrate misalignment. A misaligned substrate has high probability of damage, resulting in a costly loss of the substrate. Moreover, a misaligned substrate must be manually removed from the load lock chamber, thereby requiring costly loss of production time and diminished substrate throughput.  
           [0005]    Typically, the accuracy of substrate placement is controlled by a robot disposed in the factory interface that is utilized to move substrates between the cassettes and the load lock. However, many end-users of cluster tools are now providing the factory interface and robot disposed therein. Thus, if the accuracy and repeatability of substrate placement by the user supplied robot is not within the designed specifications of the load lock chamber, substrate damage is likely. It would be desirable for the load lock chamber to be more compatible with regard to substrate placement so that tool components (i.e., user provided factory interfaces) may be used in order to reduce system costs while increasing design flexibility.  
           [0006]    Therefore, there is a need for a load lock chamber and substrate support that corrects the orientation and position of substrates placed thereon.  
         SUMMARY OF THE INVENTION  
         [0007]    A substrate support that aligns a substrate placed thereon is generally provided. In one embodiment, a substrate support for supporting a substrate includes a support plate, a first alignment member, a second alignment member and a cylindrical member. The first alignment member is disposed proximate a first edge of the support plate while the second alignment member is disposed proximate a second edge of the support plate. The cylindrical member is disposed proximate a third edge disposed between the first and second edges of the support plate. The first alignment member extends above the support plate and is adapted to urge the substrate in a first direction while the second alignment member is adapted to urge the substrate in a second direction opposite the first direction, thereby aligning the substrate therebetween. The cylindrical member has a rotational axis aligned with the first direction and is adapted to urge the substrate in a third direction to facilitate movement of the substrate laterally between the first and second alignment members.  
           [0008]    In another aspect of the invention, a load lock chamber is provided. In one embodiment, a load lock chamber includes a chamber body having a first and a second substrate transfer port. A support plate is disposed in the chamber body and has a first surface adapted to support the substrate passed through either the first or second substrate transfer port. A first alignment member is disposed proximate a first edge of the support plate and extends above a plane of the first surface of the support plate. The alignment member is adapted to urge the substrate in a first direction. A second alignment member is disposed proximate a second edge of the support plate opposite the first alignment member and is adapted to urge the substrate in a direction opposite the first direction. A first cylindrical member is disposed proximate a third edge of the support plate and has a rotational axis aligned with the first direction. A second cylindrical member is disposed proximate a fourth edge of the support plate opposite the third edge. The second cylindrical member has a rotational axis aligned with the first direction. The first and second alignments center the substrate therebetween along a first coordinate axis while the first and second cylindrical members center the substrate therebetween along a second coordinate axis that is different than the first coordinate axis, thereby cooperatively aligning the substrate relative to the support plate. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0009]    So that the manner in which the above recited features of the present invention are attained and can be understood in detail, a more particular description of the invention, briefly summarized above, may be had by reference to the embodiment thereof which are illustrated in the appended drawings. It is to be noted, however, that the appended drawings illustrate only typical embodiments of this invention and are therefore not to be considered limiting of its scope, for the invention may admit to other equally effective embodiments.  
         [0010]    [0010]FIG. 1 is a cluster tool having one embodiment of a load lock chamber coupled the cluster tool to a factory interface;  
         [0011]    [0011]FIG. 2 is a sectional view of the load lock chamber of FIG. 1;  
         [0012]    [0012]FIG. 3 is an isometric view of a first support plate having one embodiment of an alignment apparatus;  
         [0013]    [0013]FIG. 4 is a side view of the first support plate of FIG. 3; and  
         [0014]    [0014]FIG. 5 is a sectional view of the first support plate taken along section line  5 - 5  of FIG. 4. 
     
    
       [0015]    To facilitate understanding, identical reference numerals have been used, wherever possible, to designate identical elements that are common to the figures.  
       DETAILED DESCRIPTION  
       [0016]    The invention generally provides a substrate support having an alignment mechanism that aligns or centers a substrate disposed thereon to a predetermined position. The invention is illustratively described below utilized in a dual substrate load lock chamber, such as those available from AKT, a division of Applied Materials, Inc., Santa Clara, Calif. However, it should be understood that the invention has utility in other configurations, for example, single substrate load lock chambers, multiple substrate load lock chambers, robot hand-off platforms, buffer stations and other devices utilized to support a substrate where the positional accuracy of the substrate is desired.  
         [0017]    [0017]FIG. 1 is a cross sectional view of one embodiment of a process system  150 . The process system  150  typically includes a transfer chamber  108  coupled to a factory interface  112  by a load lock chamber  100  that has a substrate alignment apparatus  162 . The transfer chamber  108  has at least one vacuum robot  134  disposed therein that is adapted to transfer substrates between a plurality of circumscribing process chambers  132  and the load lock chamber  100 . In one embodiment, one of the process chambers  132  is a pre-heat chamber that thermally conditions substrates prior to processing to enhance throughput of the system  150 . Typically, the transfer chamber  108  is maintained at a vacuum condition to eliminate the necessity of adjusting the pressures between the transfer chamber  108  and the individual process chambers  132  after each substrate transfer.  
         [0018]    The factory interface  112  generally includes a plurality of substrate storage cassettes  138  and an atmospheric robot  136 . The cassettes  138  are generally removably disposed in a plurality of bays  140  formed on one side of the factory interface  112 . The atmospheric robot  136  is adapted to transfer substrates  106  between the cassettes  138  and the load lock chamber  100 . Typically, the factory interface  112  is maintained at or slightly above atmospheric pressure.  
         [0019]    [0019]FIG. 2 is a sectional view of one embodiment of the load lock chamber  100 . The load lock chamber  100  includes a body  102  having walls  104 A,  104 B, a bottom  206  and a top  208  that define a sealable internal volume  110 . The load lock chamber  100  is typically coupled to a factory interface  112  through a port  114  disposed in the wall  104 A. A slit valve  116  selectively seals the port  114  to isolate the atmospheres of the internal volume  110  of the load lock chamber  100  and the factory interface  112 . The slit valve  116  may be opened to allow a substrate  106  to pass through the port  114  between the factory interface  112  and the load lock chamber  100 .  
         [0020]    The load lock chamber  100  is typically coupled to the transfer chamber  108  through a port  118  disposed in the wall  104 B. A slit valve  120  selectively seals the port  118  to selectively isolate the atmospheres of the internal volume  110  of the load lock chamber  100  and the transfer chamber  108 . The slit valve  120  may be opened to allow the substrate  106  to pass between the transfer chamber  108  and the load lock chamber  100 . Examples of slit valves that may be adapted to benefit from the invention are described in U.S. Pat. No. 5,579,718, issued Dec. 3, 1996 to Freerks and U.S. Pat. No. 6,045,620, issued Apr. 4, 2000 to Tepman et al., both of which are hereby incorporated by reference in their entireties.  
         [0021]    The chamber body  102  additionally includes at least one port disposed therethrough to facilitate controlling the pressure within the interior volume  110 . In the embodiment depicted in FIG. 1, the chamber body  102  includes a vent port  122  and a vacuum port  124  formed through the chamber body  102 . Valves  126 ,  128  are respectfully coupled to the vent port  122  and vacuum port  124  to selectively prevent flow therethrough. The vacuum port  122  is coupled to a vacuum pump  130  that is utilized to selectively lower the pressure within the interior volume to a level that substantially matches the pressure of the transfer chamber  108 . When the pressures between the transfer chamber  108  and the load lock chamber  100  are substantially equal, the slit valve  120  may be opened to allow processed substrates to be transferred to the load lock chamber  100  and substrates to be processed transferred to the transfer chamber  108  by the vacuum robot  124 .  
         [0022]    After placing the substrate returning from the transfer chamber  108  in the load lock chamber  100 , the slit valve  120  is closed and the valve  126  is opened thereby allowing air into the load lock chamber  100  and raising the pressure within the internal volume  110 . Typically, the air entering the interior volume  110  through the vent port  122  is filtered to minimize potential particulate contamination of the substrate. Once the pressure within in the load lock chamber  100  is substantially equal to that of the factory interface  112 , the slit valve  116  opens, thus allowing the atmospheric robot  136  to transfer of substrates between the load lock chamber  100  and the substrate storage cassettes  138  coupled to the factory interface  112 .  
         [0023]    In order to minimize the precision and accuracy required of the atmospheric robot  136 , a support plate  160  disposed within the load lock chamber  100  and adapted to receive substrates from the atmospheric robot  136 , is equipped with at least one alignment apparatus  162  that positions the substrate  106  relative to the support plate  160 . For example, the alignment apparatus  162  may correct positional inaccuracies between a deposited position of the substrate  106  as placed by the atmospheric robot  136  on the support plate  160  and a predefined (i.e., designed) position of the substrate  106  relative the support plate  160 . Having the position of the substrate  106  aligned by the alignment apparatus  162  within the load lock chamber  100  independent from conventional correction methods that utilize the atmospheric robot  136  to adjust the substrate placement allows greater flexibility and lower system costs. For example, the support plate  160  with alignment apparatus  162  provides greater compatibility between the load lock chamber  100  and user supplied factory interfaces  112  since the load lock chamber  100  is more tolerant to substrate position on the support plate  160 , thereby reducing the need for robots of great precision and/or corrective robot motion algorithms generated by the factory interface provider. Moreover, as the positional accuracy designed criteria for the atmospheric robot  136  is diminished, less costly robots may be utilized.  
         [0024]    The first support plate  160  shown in FIG. 2, has the alignment apparatus  162  disposed over a second substrate support  202  in a dual substrate handling configuration. Embodiments of the invention, however, includes at least one substrate support plate having an alignment mechanism, which may be utilized with zero or a plurality of additional support plates, some, all or none of which may include alignment mechanisms.  
         [0025]    The first support plate  160  and the second support  202  are generally configured to respectively hold substrates in a stacked parallel orientation within the load lock chamber  100  in a position accessible to both the atmospheric and vacuum robots  136 ,  134 . Typically, the first support plate  160  is utilized for holding substrates entering the transfer chamber  106  while the second support  202  is utilized for holding substrates returning to the factory interface  112 . The first support plate  160  is coupled to the chamber body  102 , typically to the bottom  206 . As seen in FIGS. 2 and 3, stanchions  204  couple the first support plate  160  to the chamber bottom  206 . The stanchions  204  are generally positioned in a spaced-apart relationship to facilitate placement of a substrate on the second support  202 . The stanchions  204  are additionally spaced wide enough to allow movement of the cooling plate  214  therebetween.  
         [0026]    The second support  202  generally holds a substrate between the first support plate  160  and the chamber bottom  206 . The second support  202  may be a plate supported by the stanchions  204  or other member. In the embodiment depicted in FIGS. 2 and 3, the second support  202  comprises a plurality of substrate support posts  230  coupled to the chamber bottom  206 , each post  230  having a distal end  232  defining a generally planar, substrate supporting surface. The posts  230  are generally arranged not to interfere with the robots  134 ,  136  during substrate transfer.  
         [0027]    Thermal control of the substrates may additionally be practiced within the load lock chamber  100 . For example, the top  208  of the chamber body  102  may include a window  210  having a radiant heater  212  mounted thereover. The heater  212  illuminates the substrate through the window  210  to heat the substrate disposed on the first support plate  160 . A cooling plate  214  may additionally be disposed between the first support plate  160  and the bottom  206  of the chamber body  102 . The cooling plate  214  includes a plurality of apertures  228  formed therethrough that allow the posts  230  to be disposed through the cooling plate  214 . Typically, the cooling plate  214  is coupled to a lift mechanism  216  disposed outside the load lock chamber  100 . The lift mechanism  216  may be actuated to move the cooling plate  214  along the posts  230 . The lift mechanism  216  moves the cooling plate  214  in close proximately to the substrate retained on the distal ends  232  of the second support  202  thereby cooling the substrate prior to handling by the atmospheric robot. Optionally, the cooling plate  214  may lift the substrate off of the section support  202  to maximize heat transfer. Typically, the cooling plate  214  is coupled to the bottom  206  of the chamber body  102  by a dynamic seal, for example, a bellows  218 . In one embodiment, the cooling plate  214  includes one or more conduits  220  coupled to a heat transfer fluid source  222  through a shaft  224  that couples the cooling plate  214  to the lift mechanism  216 . Fluid, from the fluid source  222 , is flowed through the conduits  220  to remove heat transferred from the substrate to the second support  202 .  
         [0028]    [0028]FIG. 3 depicts an isometric view of the first support plate  160  and the second support  202 . The first support plate  160  generally includes a plurality of support elements  302  that are adapted to maintain the substrate in a spaced-apart relation relative to the first support plate  160 . The height of the support elements  302  is generally configured to allow a blade of the robots  136 ,  134  between the substrate seated on the support elements  302  and the support plate  160 . Optionally, channels may be formed the support plate  160  between the support elements  302  to provide space of the blade of the robots  136 ,  134 . The support elements  302  additionally allow the substrate to move parallel to a plane of the first support plate  160  without scratching or otherwise damaging the substrates. The support elements  302  may be low friction pads, roller balls or air bearings among others. In the embodiment depicted in FIG. 3, the support elements  302  are fabricated from stainless steel or a polymer, for example, fluoropolymers or polyetherether ketone. The distal ends  232  of the second support  202  may also include support elements  302  to minimize potential damage to the substrate.  
         [0029]    The first support plate  160  is typically circumscribed by a plurality of alignment apparatus  162 . The alignment apparatus  162  may be coupled to the support plate  160  or alternatively to a portion of the chamber body  102 . The alignment apparatus  162  are adapted to cooperatively ensure placement of a substrate in a predetermined position relative to the support plate  160 . Generally, a first pair of alignment devices are configured to align a substrate along a first coordinate axis  334  while a second pair of alignment devices are configured to align the substrate therebetween in a second coordinate axis  336 , thereby cooperatively moving the substrate into a predetermined position relative to the support plate  160 . Typically, the first coordinate axis  334  is orientated perpendicular to the second coordinate axis  336 .  
         [0030]    Generally, a first alignment apparatus  330  includes at least a first alignment member  304 A and a second alignment member  304 B disposed across opposite sides of the support plate  160 . The alignment members  304 A-B are positioned respectively along a first edge  340  and a second edge  342  of the support plate  160 , and cooperatively align the substrate therebetween along the first coordinate axis  334 . A second alignment apparatus  332  generally includes a first cylinder  306 A and a second cylinder  306 B disposed across a third  344  and an opposing fourth side  346  of the support plate  160 . The first and second cylinders  306 A-B cooperatively align the substrate therebetween along the second coordinate axis  336  that is different than the first coordinate axis  334 . The first and second alignment apparatus  330 ,  332  cooperatively align the substrate in a predetermined position relative to the support plate  160  in a position that facilitates further handling and processing of the substrate without damage due to substrate misalignment.  
         [0031]    In the embodiment depicted in FIG. 3, the first alignment apparatus  330  and the second alignment apparatus  332  are disposed across the four edges  340 ,  342 ,  344 ,  346  of the support plate  160 . Each alignment apparatus  330 ,  332  generally includes at least two alignment members  304 A-D and at least two cylinders  306 A-D. The set of alignment members and cylinders comprising each alignment apparatus are typically coupled to a first surface  308  of the support plate  160  on adjacent edges of the support plate  160  and are adapted to move a mis-positioned substrate into a predetermined position. Typically, the alignment member and cylinder comprising each alignment apparatus are adapted to move the substrate in orthogonal directions, however, the alignment member and cylinder may be configured to move the substrate in other directions.  
         [0032]    [0032]FIG. 4 depicts a sectional view of the support plate  160  having the first alignment apparatus  330  disposed across opposing sides  340 ,  342  of the support plate  160 . The first alignment apparatus  330  generally includes the first alignment member  304 A and the second alignment member  304 B. The first alignment member  304 A is coupled along the first edge  340  of the support plate  160 . The first alignment member  304 A is generally fabricated from or at least partially coated with a material that minimizes marring, scratching or contamination of the substrate. In one embodiment, the first alignment member  304 A is fabricated from stainless steel or a polymer, for example, fluoropolymers or polyetherether ketone.  
         [0033]    The first alignment member  304 A generally includes a first portion  406  and a second portion  408 . The first portion  406  is generally coupled to the first surface  308  of the first support plate  160 . The first portion  406  may include a plateau  410  having a top surface  412  orientated substantially parallel to the support plate  160 . The top surface  412  is typically at an elevation above the first surface  308  of the first support plate  160  that is about equal to or greater than an elevation of the support elements  302 . Optionally, the top surface  412  may taper towards the center  414  of the first support plate  160 .  
         [0034]    The second portion  408  of the first alignment member  304 A generally projects above the first surface  308  of the first support plate  160  and the plateau  410 . The second portion  408  includes a sloping face  416  that is disposed at an acute angle relative to the first surface  308  of the support plate  160 . In one embodiment, the angle of the sloping face  416  is about 60 to about 80 degrees. Generally, the sloping face  416  is adapted to move the substrate  106  contacting therewith in a first direction  420 , generally toward the center  414  of the support plate  160 .  
         [0035]    The second alignment member  304 B is disposed opposite the first alignment member  304 A on a second edge  342  of the support plate  160 . The second alignment member  304 B includes a plateau  428 , a top surface  430  and a sloping face  426  disposed on the support plate  160  and is typically configured in a mirror image relative to the first alignment member  304 A about the center  414  of the support plate  160 . Thus, the sloping face  426  of the second support member  304 B is adapted to move a substrate contacting therewith in a direction opposite the first direction  420 .  
         [0036]    A working distance  434  between intersections of opposing plateaus and sloping faces of the first and second alignment members  304 A,  304 B is generally configured to be about equal to a positional tolerance of designed parameters for substrate location relative to the support plate  160  in the direction between the members  304 A,  304 B. A correction range  436  is generally the distance over which the sloping faces  416 ,  426  will move an out-of-position substrate into the working distance  434 . For example, as an out-of alignment substrate  106  is lowered onto the support plate  160  by the atmospheric robot (not shown), the substrate  106  contacts the sloping face  416  of the first closest alignment member, for example, the first alignment member  304 A. The angle  418  of the sloping face  416  urges the substrate  106  in the first direction  420  to capture the substrate between the opposing second alignment member  304 B. The substrate  106  continues to move along the sloping face  416  until a bottom  432  of the substrate  106  become seated on the plateaus  410 ,  428  of the first and second alignment members  304 A,  304 B, at which point, the substrate  106  has moved within the working distance  434  and is correctly positioned (with respect to an coordinate axis defined by the first direction) for safe transfer without damage. The other alignment members are similarly configured.  
         [0037]    The first cylinder  306 A is generally coupled to the support plate  160  and has a rotational axis  440  aligned with the first direction  420  (i.e., the rotational axis  440  is within a few degrees of the first direction  420 ). In one embodiment, the axis  440  is parallel to the first direction  420 . The orientation of the axis  440  may alternatively be disposed at an acute angle with the first direction  440 . In one embodiment, the axis  440  is positioned at an elevation relative the first surface  308  of the support plate  160  about equal to or slightly less than the elevation of the top surface  412  of the plateau  410  of the first alignment element  304 A. The first cylinder  306 A may be fabricated from stainless steel or a polymer, for example, fluoropolymers or polyetherether ketone.  
         [0038]    Typically, the first cylinder  306 A is positioned along an edge of the support plate  160  adjacent the first edge  340  along which the first alignment member  304 A is disposed. The first cylinder  306 A is generally positioned so that at least a portion of the cylinder is inwards of the intersection of the sloping face  416  and the top surface  412 . The third cylinder  306 C is generally positioned along the same edge of the support plate  160  as the first cylinder  306 A.  
         [0039]    [0039]FIG. 5 is a sectional view of the support plate  160  illustrating the interaction between the substrate  106  and the first and second cylinders  306 A and  306 B. The first and second the first and second cylinders  306 A-B are generally positioned across opposite edges of the support plate  160  and cooperatively align the substrate therebetween along a second coordinate axis  336  that is different than the first coordinate axis  334 . The cylinders  306 A-B may be used in conjunction with the first and second alignment members  304 A-B to cooperatively align the substrate in a predetermined position relative to the support plate  160  in a position that facilitates further handling and processing of the substrate without damage due to substrate misalignment.  
         [0040]    The first cylinder  306 A is generally coupled to the support plate  160  along a third edge  344  that couples the first and second edges  340 ,  342  shown in FIG. 4. The rotational axis  440  of the first cylinder  306 A is typically disposed parallel to the third edge  344 . The first cylinder  306 A has an outer diameter  502  that is adapted to move a substrate in contact therewith in a second direction  504  that is typically, but not exclusively, orthogonal to the first direction  420  depicted in FIG. 4. The outer diameter  502  of the first cylinder  306 A is typically fabricated or coated with a material that does not scratch, mar or otherwise contaminate the substrate  106 . The second cylinder  306 B is generally positioned along a fourth edge  346  of the support plate  160  opposite the third edge  344 . The third cylinder  306 D includes an outer diameter  514 . The outer diameter  514  is adapted to move a substrate in contact therewith in a direction opposite the second direction  504 . Thus, the first and second cylinders  306 A-B may cooperatively move a substrate therebetween to a predetermined position.  
         [0041]    A working distance  510  defined between the outer diameters  502 ,  514  of the first and second cylinders  304 A,  304 B is generally configured to be about equal to the positional tolerance of designed parameters for substrate location relative to the support plate  160  along the second coordinate axis  336  defined between the cylinders  304 A,  304 B. A correction range  512  is generally distance over which the cylinders  306 A,  306 B will move an out-of-position substrate into the working distance  510 . The diameter of the correction range  512  is equal to or slightly less than the diameter of the cylinders  306 A,  306 B. The diameter of the cylinders  306 A,  306 B should be selected as not to stick up too high as to interfere with the substrate when transported by either the robots  134 ,  136  shown in FIG. 1. For example, as an out-of alignment substrate  106  is lowered onto the support plate  160  by the atmospheric robot (not shown), the substrate  106  contacts the outer diameter  502  of the closest cylinder, for example, the first cylinder  306 A. The offset between the point of contact between the substrate  106  and the outer diameter  502  and the rotational axis  440  causes the first cylinder  306 A to rotate, thus urging the substrate  106  in the second direction  504  toward the center of the support plate  160  and the second cylinder  306 B. The substrate  106  continues to move in the second direction  504  as the cylinder  306 A rotates until the bottom  432  of the substrate  106  become seated on the plateaus of the first and second alignment members  304 A,  304 B, at which point, the substrate  106  has moved within the working distance  510  and is correctly positioned for safe transfer without damage with respect to the second coordinate axis  336 .  
         [0042]    While the forgoing is directed to the some embodiments of the present invention, other and further embodiments of the invention may be devised without departing from the basic scope thereof, and the scope thereof is determined by the claims that follow.