Abstract:
Substrate supports for use in process chambers having limited physical space for configuring chamber components are disclosed. In some embodiments, a substrate support may include a body having a support surface; a utilities feed coupled to the body and comprising a second portion coupled to and extending laterally away from the body beyond a diameter of the body, and first portion coupled to the second portion and extending perpendicularly away from the body; and a cover plate movably disposable beneath and with respect to the body between a first position disposed completely beneath the body, and a second position wherein the cover plate is disposed over the first portion of the utilities feed and includes a first portion disposed beneath the body, and wherein the first portion has a curved edge having a radius equal to the distance from a central axis of the support surface to the curved edge.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims benefit of U.S. provisional patent application Ser. No. 61/638,622, filed Apr. 26, 2012, which is herein incorporated by reference in its entirety. 
     
    
     FIELD 
       [0002]    Embodiments of the present invention generally relate to semiconductor manufacturing. 
       BACKGROUND 
       [0003]    Various semiconductor manufacturing processes utilize cluster tools having multiple load lock chambers. In some embodiments, the multiple load lock chambers are stacked vertically. However, such a configuration presents a limited physical space for providing access to the chambers for certain facilities, particularly for the upper chamber of the stacked chambers. For example, the inventors have observed that uniform pumping around a substrate disposed within the upper load lock chamber may be negatively impacted by the configuration of the pump port and other physical components within the chamber due to the lack of vertical space to configure the process chamber. 
         [0004]    Accordingly, the inventors have provided an improved apparatus for uniformly pumping within stacked process chambers or in other chambers were limited physical space may be an issue. 
       SUMMARY 
       [0005]    Embodiments of substrate supports for use in process chambers having limited physical space for configuring chamber components are disclosed herein. In some embodiments, a chamber for handling a substrate may include a first chamber body having an inner volume defined in part by a floor, a ceiling, and one or more sidewalls; a ledge extending radially inward from the one or more sidewalls to define a central opening having a first diameter, wherein the ledge separates the inner volume into a processing volume disposed on one side of the ledge adjacent to the ceiling and a pumping volume disposed on an opposing side of the ledge adjacent to the floor; a pump port disposed through the floor of the first chamber body; a first opening disposed through the floor of the chamber body; a substrate support disposed in the processing volume coaxially with respect to the central opening, the substrate support having a second diameter that is larger than the first diameter, where the substrate support is disposed in a spaced apart relation with respect to the ledge such that a gap is defined between a lower surface of the substrate support and the ledge; a utilities feed for providing utilities to the substrate support, wherein the utilities feed comprises a first portion disposed through the first opening and a second portion that extends laterally beneath the substrate support from the first opening to a location on a lower surface of the substrate support where the utilities feed is coupled to the substrate support; a notch disposed through the ledge from the central opening toward a sidewall of the one or more sidewalls, wherein at least a portion of the notch is aligned with the first opening and sized to facilitate passing the first portion of the utilities feed into the first opening; and a cover plate having a first edge that conforms to the geometry of the notch and a second edge with a radius equal to that of the central opening, wherein the cover plate is movably disposed between a first position that fills the notch and aligns the curved edge with the central opening such that the central opening and the curved edge together form a circle, and a second position that exposes the notch such that the first portion of the utilities feed can pass through the notch and into the first opening during installation. 
         [0006]    In some embodiments, a substrate support is provided for use in a chamber for handling a substrate that comprises a first chamber body having an inner volume defined in part by a floor, a ceiling, and one or more sidewalls, a ledge extending radially inward from the one or more sidewalls to define a central opening having a first diameter, wherein the ledge separates the inner volume into a processing volume disposed on one side of the ledge adjacent to the ceiling and a pumping volume disposed on an opposing side of the ledge adjacent to the floor, a pump port and a first opening disposed through the floor of the first chamber body, and a notch disposed through the ledge from the central opening toward a sidewall of the one or more sidewalls, wherein at least a portion of the notch is aligned with the first opening and sized to facilitate passing a portion of the substrate support therethrough. In some embodiments, the substrate support may include a substrate support sized to be disposed in the processing volume coaxially with respect to the central opening, the substrate support having a second diameter that is larger than the first diameter, where the substrate support, when installed in the chamber, is disposed in a spaced apart relation with respect to the ledge such that a gap is defined between a lower surface of the substrate support and the ledge; a utilities feed for providing utilities to the substrate support, wherein the utilities feed comprises a first portion disposed through the first opening and a second portion that extends laterally beneath the substrate support from the first opening to a location on a lower surface of the substrate support where the utilities feed is coupled to the substrate support; and a cover plate having a first edge that conforms to the geometry of the notch and a second edge with a radius equal to that of the central opening, wherein the cover plate is movably disposed between a first position that fills the notch and aligns the curved edge with the central opening such that the central opening and the curved edge together form a circle, and a second position that exposes the notch such that the first portion of the utilities feed can pass through the notch and into the first opening during installation. 
         [0007]    In some embodiments, a substrate support may include a body having a support surface to support a substrate; a utilities feed coupled to the body to provide utilities to the body, wherein the utilities feed comprises a second portion coupled to the body and extending laterally away from the body beyond a diameter of the body, and first portion coupled to the second portion and extending perpendicularly away from the body; and a cover plate movably disposable beneath and with respect to the body between a first position and a second position, wherein in the first position the cover plate is disposed predominantly beneath the body and not over the first portion of the utilities feed, wherein in the second position the cover plate is disposed over the first portion of the utilities feed and includes a portion disposed beneath the body, and wherein the portion disposed beneath the body has curved edge aligned with a radial arc of the body having a radius equal to the distance from a central axis of the support surface to the curved edge. 
         [0008]    Other and further embodiments are discussed below. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0009]    So that the manner in which the above recited features of the present invention can be understood in detail, a more particular description of the invention, briefly summarized above, may be had by reference to embodiments, some of 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]      FIG. 1  depicts a perspective view of a chamber body in accordance with some embodiments of the present invention. 
           [0011]      FIG. 2  depicts a sectional view through a pumping port of a chamber body in accordance with some embodiments of the present invention. 
           [0012]      FIG. 3  depicts a sectional view through a first opening of a chamber body in accordance with some embodiments of the present invention. 
           [0013]      FIG. 4  depicts a perspective view of a substrate support, utilities feed, and cover plate assembled together in accordance with some embodiments of the present invention. 
           [0014]      FIG. 5  depicts a perspective view of a substrate support, utilities feed, and cover plate assembled together in accordance with some embodiments of the present invention. 
           [0015]      FIG. 6A  depicts a perspective view of a first surface of the cover plate in accordance with some embodiments of the present invention. 
           [0016]      FIG. 6B  depicts a perspective view of a second surface of the cover plate in accordance with some embodiments of the present invention. 
           [0017]      FIG. 7  depicts a perspective schematic view of a substrate support, and utilities feed assembled disposed within a chamber body in accordance with some embodiments of the present invention. 
           [0018]      FIG. 8  depicts a perspective view of a substrate support and cover plate disposed within a chamber body in accordance with some embodiments of the present invention. 
           [0019]      FIG. 9  depicts a top view of a cover plate in a second position in accordance with some embodiments of the present invention. 
           [0020]      FIG. 10  depicts a top view of a cover plate in a first position in accordance with some embodiments of the present invention. 
       
    
    
       [0021]    To facilitate understanding, identical reference numerals have been used, where possible, to designate identical elements that are common to the figures. The above drawings are not to scale and may be simplified for illustrative purposes. 
       DETAILED DESCRIPTION 
       [0022]    Embodiments of the present invention provide an improved apparatus for uniformly pumping around a substrate within a substrate processing chamber. Embodiments of the present invention may be utilized, in a non-limiting example, in a load lock chamber with limited vertical space, such as a stacked load lock chamber. Embodiments of the present invention may advantageously be used in any load lock or other substrate processing chamber where vertical space is limited. For example, the present invention may be used in combination with the dual load lock chamber described in PCT Patent Application Publication WO2012118897, published Sep. 7, 2012, entitled “Abatement and Strip Process Chamber in a Dual Loadlock Configuration”. Alternatively, the present invention may be used in combination with the load lock chamber described in PCT Patent Application Publication WO 2012/148568, published Nov. 1, 2012, entitled “Method and Apparatus for Substrate Transfer and Radical Confinement”. 
         [0023]      FIG. 1  is a perspective view of a load lock chamber  100  in accordance with some embodiments of the present invention.  FIG. 2  and  FIG. 3  depict a sectional view of the load lock chamber body  100  in accordance with some embodiments of the present invention. The load lock chamber  100  includes a first chamber body  102 . The first chamber body  102  has an inner volume  104  that is defined by a floor  106  and one or more sidewalls  108 . In some embodiments, the load lock chamber  100  includes a first chamber body  102  disposed above a second chamber body as described in PCT Patent Application Publication WO2012118897. In some embodiments, the first chamber body  102  and the second chamber body are coupled together by bolts, welding or brazing. In some embodiments, the first chamber body  102  and the second chamber body are integrally formed, such as being formed from a single billet of material. 
         [0024]    The first chamber body  102  has a ledge  110  that extends radially inward from the one or more sidewalls  108 . The ledge  110  separates the inner volume  104  into a processing volume  114  on one side of the ledge  110 , and a pumping volume  116  on an opposing side of the ledge  110 . The first chamber body  102  also comprises a pump port  118  and a first opening  120 . The pump port  118  and the first opening  120  are both disposed through the floor  106  of the first chamber body  102 , proximate a side of the pumping volume  116 . The pump port  118  and the first opening  120  are fluidly coupled to the inner volume  104  of the first chamber body  102 . A central opening  112  is predominantly defined by the inner diameter of the ledge  110 . A notch  122  is disposed through the ledge  110  and extends the central opening  112  toward a sidewall  108 . At least a portion of the notch  122  is vertically aligned with the first opening  120  to permit access to the first opening  120  from the processing volume  114  side of the ledge  110 . 
         [0025]    A substrate support may be disposed within the first chamber body  102  to support a substrate during processing.  FIGS. 4 and 5  depict a perspective view of a substrate support  400 , a utilities feed  402 , and a cover plate  412  assembled together in accordance with some embodiments of the present invention suitable for use in the first chamber body  102 . In some embodiments, the substrate support  400  includes a body which may comprise an upper plate  404  having an upper surface and a lower surface. The upper plate  404  is configured to support a substrate. In some embodiments, a lower plate  406  may be attached to the lower surface of the upper plate  404 . A heating element may optionally be disposed between the upper plate  404  and the lower plate  406 . In some embodiments, the heating element may be disposed in channels formed on an upper surface of the lower plate  406 , a lower surface of the upper plate  404 , or combinations thereof. The heating element may be a resistive heater or conduits arranged to flow a heat transfer fluid, or the like. In some embodiments, the lower plate  406  has an outer diameter that is larger than the outer diameter of the upper plate  404 . The upper plate  404  and the lower plate  406  may be joined together in any suitable fashion, such as by bolts, clamps, welding, brazing, or the like. In some embodiments, the upper plate  404  and the lower plate  406  may be formed from metal, such as aluminum. 
         [0026]    A utilities feed  402  is coupled to the substrate support  400  for providing utilities to the substrate support  400 . The utilities feed  402  has a first portion  408  that may be disposed through the first opening  120  when installed and a second portion  410  that extends laterally underneath the substrate support  400  from the first opening  120  to a first location on the lower plate  406  of the substrate support  400  where the utilities feed  402  is coupled to the substrate support  400 . In some embodiments, the first location may be coincident with a central axis of the support surface of the substrate support. In some embodiments, the first portion  408  of the utilities feed  402  comprises an extension tube. In some embodiments, the second portion  410  of the utilities feed  402  comprises a cantilevered tube. The cantilevered tube extends from a backside near the center of the lower plate  406  radially outward to connect with the extension tube disposed through the first opening  120  of the first chamber body  102 . 
         [0027]    The cantilevered tube and the extension tube provide a passageway for power supplies, sensors and other wiring to be used by the substrate support  400 . In some embodiments, a heater power source, a sensor signal receiver and a chucking control unit are wired to the substrate support  400  through the passageway in the cantilevered tube and the extension tube. Other substrate support configurations may utilize partially or completely different utilities. 
         [0028]    A more detailed description of the substrate support  400  can be found in PCT Patent Application Publication WO2012118606, published Sep. 7, 2012, entitled “Thin Heated Substrate support”. 
         [0029]      FIGS. 6A and 6B  depict a cover plate  412  having a first primary surface  416  and an opposing second primary surface  418 . The cover plate  412  has substantially the same geometry as the notch  122 . For example, the cover plate  412  has a first edge  420  that corresponds to the shape of the notch  122  and a second edge having a radius substantially equal to the radius of the central opening  112 . The cover plate may be configured to interface with the substrate support  400  and be radially movably disposed with respect to the substrate support  400 . For example, in some embodiments, the cover plate  412  may have a plurality of features, such as a plurality of pins  414 , extending from the second surface  418  to interface with the second portion  410  of the utilities feed  402  to allow radial movement while preventing the cover plate  412  from sliding off of the second portion  410  of the utilities feed  402 . 
         [0030]    Returning to  FIG. 4  and  FIG. 5 , the cover plate  412  may be movably disposed between the second portion  410  of the utilities feed  402  and the lower plate  406 . The cover plate  412  can slide along the length of the second portion  410  of the utilities feed  402  between a first position to facilitate processing and a second position to facilitate installation and removal of the substrate support  400 . 
         [0031]    In some embodiments, as depicted in  FIGS. 7 through 10 , the substrate support  400  is disposed in the processing volume  114 , coaxially with respect to the central opening  112  to define a substantially uniform gap between a lower surface of the substrate support  400  adjacent to the ledge  110  and an upper surface of the ledge  110 . During installation of the substrate support  400  into the processing volume  114 , the cover plate may be placed in the second position, as depicted in  FIG. 10 . Sliding the cover plate  412  to the second position exposes the notch  122  and allows the first portion  408  of the utilities feed  402  to pass through the notch  122  and into the first opening  120 . At least a portion of the notch  122  is aligned with the first opening  120  to facilitate passing the first portion  408  of the utilities feed  402  into the first opening  120 . Having the notch  122  exposed facilitates a line of sight view into the first opening  120  which advantageously facilitates proper alignment of the first portion  408  of the utilities feed, and therefore, of the substrate support  400  when installing the substrate support in the process chamber. 
         [0032]    Once the substrate support  400  is installed, the cover plate  412  may be moved into the first position, as depicted in  FIGS. 8 and 9 , which fills the notch  122  and aligns the second edge of the notch  122  with the central opening  112 . In this position, the central opening  112  and the curved edge  420  form a complete circle and provide a substantially uniform gap in both width and length around the entire periphery of the substrate support  400  between the upper surfaces of the ledge  110  and the curved edge  420  of the cover plate  412  and the lower surface of the body of the substrate support  400 . 
         [0033]    Accordingly, in some embodiments and as best depicted in  FIG. 7 , a portion of the substrate support  400  is disposed above and in a spaced apart relation with respect to the ledge  110 , thereby creating a substantially uniform gap  700  between the lower plate  406  of the substrate support  400  and the ledge  110 . The uniform gap  700  allows for substantially uniform gas flow from the processing volume  114  above the substrate support  400  to the pumping volume  116  and pumping port  118  below the substrate support  400 . In some embodiments, a peripheral edge of the lower plate  406  overlaps the ledge  110  creating a restricted flow condition and enhancing uniform gas flow from the processing volume  114 . The restricted flow condition may be, but need not be, a choked flow condition. However, the restricted flow condition should be sufficient to facilitate providing a more uniform pressure around the perimeter of the substrate support  400 . In some embodiments, the gap  700  may illustratively be about  0 . 26  inches, although other dimensions, both smaller and larger, may be used. 
         [0034]    In some embodiments as illustrated in  FIGS. 4 and 5 , one or more support structures, for example first support  422  and second support  426 , may be disposed on the lower surface of the substrate support  400  near a central axis of the substrate support  400 . When present, the first support  422  extends through an opening in the second portion  410  of the utilities feed  402 . The first support  422  comprises a surface  425  configured to rest on the floor  106  of the first chamber body  102  to stabilize and provide vertical support to the substrate support  400  when installed. In some embodiments, the support structure comprises a locating structure, such as the boss  427 , configured to locate the substrate support  400  within the volume  104 . The boss  427  may be received in a cooperating feature, such as a suitably positioned and formed cavity (not shown) in the chamber floor  106 . 
         [0035]    In some embodiments, the first support  422  may comprise one or more holes  424  (two shown) formed through the support and sized to accept a fastener (not shown), such as a threaded fastener, to couple the substrate support  400  to the chamber floor  106 . 
         [0036]    The second support  426  may be disposed about the first support  422  and have a support surface, such as the raised lip  428  near the periphery. The raised lip  428  may be coplanar with the surface  425  and configured to rest on the floor  106  of the first chamber body  102  to stabilize and provide vertical support to the substrate support  400 . The second support  426  may include additional support surfaces. The raised lip  428  may include a vent  430  to facilitate equalization of pressure between the volume  104  and the volume formed between the second support  426  and the chamber floor  102 . 
         [0037]    In some embodiments, the first and second supports  422 ,  426  may also thermally isolate the substrate support  400  from the chamber floor  102 , i.e.,  422  and  426  may also be thermal isolators. In some embodiments, the first and second supports  422 ,  426  may be fabricated of a process compatible material having a low thermal conductivity, or may provide a small contact area (e.g., surfaces  425 ,  428 ) between the substrate support and the chamber body to limit conductive heat loss from the substrate support  400  to the chamber body through the first and second supports  422 ,  426 . 
         [0038]    In some embodiments, the first and second supports  422 ,  428  are sized such that the support surface of the substrate support  400  is maintained in a substantially horizontal plane and is disposed above the ledge  110 , thereby creating a gap between a lower surface of the substrate support  400  and the ledge  110 . 
         [0039]    While the foregoing is directed to embodiments of the present invention, other and further embodiments of the invention may be devised without departing from the basic scope thereof.