Abstract:
A semiconductor substrate undergoing processing to fabricate integrated circuit devices thereon is spun about a rotational axis while introducing liquid onto a surface of the substrate. An annular-shaped sheet of liquid is formed on the surface, the sheet of liquid having an inner diameter defining a liquid-free void. The size of a diameter of the void is reduced by manipulation of the annular-shaped sheet of liquid. The void may then be enlarged until the surface is substantially dry. The annular-shaped sheet of liquid may be formed and altered by selectively moving a contact area on the surface of the substrate on which the liquid is introduced. Systems for processing a substrate and configured to deposit and manipulate a sheet of liquid thereon are also disclosed.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
   This application is a divisional of application Ser. No. 11/359,730, filed Feb. 22, 2006, now U.S. Pat. No. 7,470,638, issued Dec. 30, 2008. The disclosure of which is hereby incorporated by reference in its entirety. 

   BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   The present invention relates generally to methods and systems for removing liquids from surfaces of semiconductor substrates such as wafers. More particularly, the present invention relates to systems and methods for reducing or eliminating the presence of residues on a substrate surface following the removal of liquids therefrom by selective manipulation of the liquids on the substrate surface. 
   2. Discussion of Related Art 
   Integrated circuit devices such as microprocessors and memory devices are typically fabricated upon a semiconductor substrate, such as a full or partial wafer of semiconductor material (e.g., silicon, indium phosphide, gallium arsenide, etc.), or other substrate including one or more layers of semiconductor material thereon, such as a silicon-on-insulator (SOI) type substrate (such as, a silicon-on-glass (SOG), silicon-on-sapphire (SOS), silicon-on-ceramic (SOC), etc.), or any other suitable fabrication substrate. A large number of identical integrated circuit devices typically are fabricated on a single substrate, and the substrate is then diced, sawed, or cut, to physically separate individual semiconductor devices from one another. 
   Semiconductor substrates are subjected to a significant number of individual processes during the fabrication of integrated circuitry thereon. These processes often include growth or deposition of material layers, ion doping or implanting, photolithography processes, etc. These processes may be preceded or followed by cleaning steps that involve, for example, scrubbing, spray cleaning, and other such processes. At the completion of cleaning, the substrate may be further processed to remove the cleaning agents and contaminant materials from the surface of the substrate to prevent the formation of contaminating residue on the substrate surface. Often, the last step in a cleaning process includes a rinsing step using clean, de-ionized water followed by a drying process. 
   For example, it is known in the art to spin a fabrication substrate about a rotational axis extending through the center of the substrate and perpendicular to a major plane thereof, while directing a stream of clean de-ionized water onto a surface of the substrate. A substrate may be placed in a spin rinse drier (SRD) that includes a platform coupled to a drive motor. The drive motor may cause the platform to spin at a velocity of, for example, up to 4,000 revolutions per minute (rpm). A stream of water may be directed onto the surface of the substrate while it is spinning to rinse contaminants from the surface of the substrate. 
   Typically, a rinse liquid is applied to an entire surface of the substrate, including the center of rotation thereof, which is a point on the surface at which the axis about which the substrate is rotated intersects the surface of the substrate to which liquid is applied and removed. As the substrate spins, centrifugal forces cause the liquid to fan out across the surface of the substrate, thereby forming a substantially continuous sheet or film of liquid covering the surface of the substrate. To dry the surface of the substrate, the substantially continuous sheet or film of liquid is removed from the surface of the substrate by interrupting the flow of liquid onto the surface of the substrate while continuing to spin the substrate. Centrifugal forces acting on the liquid cause it to slide off from (or otherwise be removed from) the surface of the substrate in a generally radially outward direction from the center of rotation toward the lateral edges of the substrate. 
   Often, traces or residue of contaminant material or other unwanted matter, which may be referred to as “water marks” or “doilies,” are left behind on the surface of the substrate after the liquid has been removed from the substrate. These traces or residue may include solid matter such as, for example, silica or other materials left behind by prior processing of the substrate, and generally are undesirable as they may interfere with subsequent processing of the substrate. For example, if the rinse process is followed by an etch process in which a portion of the substrate underlying a water mark is to be etched, the solid matter forming the water mark may act as a mask to prevent or block the etch process on the underlying surface of the subject, thereby generating a defect in the structure being defined by the etch on the substrate. If the rinse process is followed by an ion implant process, in which ions of a selected material are to be implanted in a portion of the substrate underlying a water mark, the solid matter forming the water mark may prevent or block the ion implant process, thereby generating a defect in the portion of the substrate, such as a source or drain region, being implanted. 
   In view of the foregoing, it would be desirable to provide methods and systems for rinsing and drying a semiconductor substrate such as a wafer that minimizes water marks or other contaminant residue or matter left behind on the surface of the substrate. 
   BRIEF SUMMARY OF THE INVENTION 
   In one aspect, the present invention includes a method for processing a semiconductor substrate which, for the sake of convenience, may also be termed a “fabrication substrate” herein to signify its status as a semiconductor substrate under fabrication. The fabrication substrate is continuously spun about an axis of rotation while a stream of liquid is directed onto a surface of the fabrication substrate and, in so doing, a substantially continuous annular-shaped sheet or film of the liquid is formed on the surface of the fabrication substrate. The annular-shaped sheet or film of liquid has an inner diameter defining a substantially liquid-free void. The substantially continuous annular-shaped sheet or film of liquid is then manipulated by one or more techniques to reduce a size of the inner diameter of the annular-shaped sheet or film. The substantially liquid-free void may then be enlarged until the surface is substantially dry. 
   In yet another aspect, the present invention includes a method for processing a semiconductor substrate with a liquid. The semiconductor substrate is continuously spun about a rotational axis, and liquid is introduced onto a contact area on a surface of the semiconductor substrate. The area or region on the surface of the semiconductor substrate onto which the stream of liquid is directed is referred to herein as a “contact area.” The contact area is positioned at a first position on the surface of the semiconductor substrate that includes an intersection between the surface of the substrate and the rotational axis. The contact area is moved in a radially outward direction from the first position to a second position to form a substantially annular-shaped sheet or film of the liquid on the surface of the semiconductor substrate. The contact area does not include the intersection between the surface of the semiconductor substrate and the rotational axis in the second position. The contact area is then moved in a radially inward direction from the second position to a third position located radially between the first position and the second position to reduce an inner diameter of the substantially annular-shaped sheet or film of the liquid. The contact area does not include the intersection between the surface of the semiconductor substrate and the rotational axis in either the second position or the third position. 
   In an additional aspect, the present invention includes a system for processing a fabrication substrate. The system includes a rotatable support member configured to support a fabrication substrate to be processed using the system, a rotation actuator device coupled to the support member and configured to rotate the support member about a rotational axis, and means for dispensing liquid onto a contact area on a surface of the fabrication substrate. The means for dispensing liquid may include at least one liquid-dispensing device that is configured and located to dispense liquid onto a contact area on the surface of the fabrication substrate to be carried by the support member. The system further includes a computer device in communication with the means for dispensing liquid, and the computer device is configured under control of a program to provide the contact area in a first position that includes an intersection between the surface of the fabrication substrate as carried by the support member and the rotational axis, to move the contact area in a radially outward direction from the first position to a second position, and to move to the contact area in a radially inward direction from the second position to a third position radially between the first position and the second position. The contact area does not include the intersection between the surface of the fabrication substrate and the rotational axis in either the second position or the third position. 
   The features, advantages, and alternative aspects of the present invention will be apparent to those skilled in the art from a consideration of the following detailed description taken in combination with the accompanying drawings. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     While the specification concludes with claims particularly pointing out and distinctly claiming that which is regarded as the present invention, the advantages of this invention can be more readily ascertained from the following description of the invention when read in conjunction with the accompanying drawings in which: 
       FIG. 1  is a cross-sectional side view of a system for removing liquid from a fabrication substrate in accordance with teachings of the present invention; 
       FIGS. 2A-2D  are top plan views of the fabrication substrate shown in  FIG. 1  illustrating sequential contact areas of liquid directed toward the surface of the fabrication substrate by at least one liquid-dispensing element of the system shown in  FIG. 1 ; 
       FIGS. 3A-3D  are top plan views like those shown in  FIGS. 2A-2D  illustrating an additional contact area resulting from the direction of additional liquid toward the surface of the fabrication substrate; 
       FIG. 4A  is a side view of a fabrication substrate and another embodiment of a liquid-dispensing element that may be used in the system shown in  FIG. 1 ; 
       FIG. 4B  is a top plan view of the fabrication substrate and the liquid-dispensing element shown in  FIG. 4A ; and 
       FIG. 5  is a top plan view of a fabrication substrate and another embodiment of a liquid-dispensing element that may be used in the system shown in  FIG. 1 . 
   

   DETAILED DESCRIPTION OF THE INVENTION 
   In the description which follows, like features and elements have been identified by the same or similar reference numerals for ease of identification and enhanced understanding of the disclosure hereof. Such identification is by way of convenience for the reader only, however, and is not limiting of the present invention or an implication that features and elements of various components and embodiments identified by like reference numerals are identical or constrained to identical functions. 
   An illustrative system  10  that embodies teachings of the present invention is shown in  FIG. 1 . By way of example and not limitation, the system  10  may function as a spin, rinse, dry (SRD) system. The system  10  may include a rotatable support member  12  that is configured to support a fabrication substrate  14  such as, for example, a full or partial semiconductor wafer or other bulk semiconductor substrate that is to be processed using the system  10 . For example, the support member  12  may comprise a substantially planar member. The fabrication substrate  14  may be secured to the support member  12  by, for example, using a vacuum chuck or one or more mechanical clamps. In other embodiments, the rotatable support member  12  may include a plurality of structurally supported rollers configured to contact and grip the fabrication substrate  14  substantially along the peripheral edges thereof, as known in the art. The particular shape or configuration of the support member  12  does not contribute to the present invention, and as such, systems including any type or configuration of a support member  12  are within the scope of the present invention. 
   The system  10  may further include a rotation actuator device  16  that is operatively coupled to, or otherwise associated with, the support member  12  and configured to cause the support member  12  to rotate about a rotational axis  20 . By way of example and not limitation, the rotation actuator device  16  may include an electrical motor configured to spin a shaft  18  at a selectively variable speed, and the shaft  18  may be structurally coupled to the support member  12 . The rotation actuator device  16  may be configured to spin the shaft  18  and the support member  12  in either a clockwise or counter-clockwise direction, as indicated by the directional arrow  17  shown in  FIG. 1 . In additional embodiments, the rotation actuator device  16  may be directly coupled to the support member  12  without the use of an intermediate shaft  18  or other element for transmitting the kinetic energy generated by the rotation actuator device  16  to the support member  12 . 
   The system  10  also includes one or more liquid dispensers  22 , each of which may be configured and located to direct at least one stream of liquid  24  selectively toward a surface  15  of the fabrication substrate  14 . By way of example and not limitation, each liquid dispenser  22  may include a simple open-ended tube or conduit or a liquid-dispensing nozzle coupled to an outlet of a tube or conduit in communication with a liquid source. The stream of liquid  24  may include a substantially continuous column of liquid  24 , or a spray or drip of substantially discontinuous droplets of liquid  24 . Systems that embody teachings of the present invention, however, may include any other type or configuration of a liquid-dispensing element as long as the liquid-dispensing element is configured and oriented to direct a stream of liquid  24  onto at least one surface  15  of the fabrication substrate  14 . 
   In one particular embodiment shown in  FIG. 1 , the system  10  may include two liquid dispensers  22 , each configured, located and oriented to direct a stream of liquid  24  toward a surface of the fabrication substrate  14 . Liquid supply lines  30  may be used to supply liquid  24  from a liquid source (not shown) to the one or more liquid dispensers  22 . Selectively controllable flow valves  32  may be provided in the liquid supply lines  30  for selectively controlling the flow of liquid  24  through the liquid supply lines  30  to the liquid dispensers  22 . 
   A liquid dispenser actuator  26  may be coupled to or otherwise operatively associated with each liquid dispenser  22  and configured to cause the liquid dispenser  22  to dispense a stream of liquid  24  onto a selected, or desired, contact area on the surface of the fabrication substrate  14  (e.g., by selectively moving the liquid dispenser  22 ), as discussed in further detail below. 
   By way of example and not limitation, each liquid dispenser actuator  26  may be configured to move a liquid dispenser  22  in a linear direction relative to the fabrication substrate  14  as indicated by the directional arrows  27  in  FIG. 1 . Additionally, and without limiting the scope of the present invention, each liquid dispenser actuator  26  may be supported by and cooperate with a stationary member  28 , such as that shown in  FIG. 1 . The stationary member  28  may include, for example, a simple horizontally extending arm that is structurally coupled to an outer housing  54  of the system  10 . Any other type or configuration of stationary member  28  may be used in the system  10 . By way of example and not limitation, each liquid dispenser actuator  26  may include an electromechanical device comprising an electrically driven gear set cooperative with teeth on the stationary member  28 , a stepper motor cooperative with stationary member  28 , or a pneumatically or hydraulically driven piston attached at one end to the stationary member  28 . 
   In additional embodiments, systems that incorporate teachings of the present invention may include liquid dispensers  22  that move in any other manner (e.g., nonlinear) or direction relative to the fabrication substrate  14  or liquid dispensers  22  that are stationary relative to the fabrication substrate  14  but capable of altering the position at which a stream of liquid  24  dispensed thereby contacts the surface  15  of the fabrication substrate  14 . For example, systems that embody teachings of the present invention may include liquid dispensers  22  that are stationary relative to fabrication substrate  14  and configured to selectively vary the position at which the stream of liquid  24  dispensed thereby contacts the surface of the fabrication substrate  14  in response to selective variations in the liquid pressure at which the liquid  24  is dispensed from the liquid dispensers  22 . Furthermore, systems that incorporate teachings of the present invention may be configured to move a fabrication substrate in a lateral direction in the X-Y plane parallel to the major plane of the fabrication substrate relative to a stationary liquid dispenser  22  and/or stream of liquid  24  dispensed thereby. 
   The system  10  may include a liquid container  36  positioned to laterally surround the fabrication substrate  14  and configured to capture liquid  24  dispensed from the liquid dispensers  22  as the liquid  24  is spun off of the fabrication substrate  14 . For example, the liquid container  36  may include a bottom wall  38  and at least one lateral sidewall  40 . At least a portion of the lateral sidewall  40  may be configured to deflect liquid  24  into the container  36  toward the bottom wall  38  as the liquid  24  is spun off of the fabrication substrate  14  and impinges against the lateral sidewall  40 . As shown in  FIG. 1 , the liquid container  36  may be generally configured as a bowl having a bottom wall  38 , a sidewall  40 , and a top opening  42  through which a fabrication substrate  14  may be positioned on the support member  12 . At least a portion of the sidewall  40  may be disposed at an angle with respect to the fabrication substrate  14  and oriented to deflect liquid  24  spinning off from the fabrication substrate  14  towards the bottom wall  38  and into the liquid container  36 . The liquid container  36  also may include a drain  44  for removing liquid  24  from the container  36  for disposal, recycling, or further processing. 
   The liquid container  36  may be configured to move relative to the support member  12  between a first position in which the support member  12  is substantially disposed outside the liquid container  36  and a second position in which the support member  12  is substantially disposed inside the liquid container  36 . In such a configuration, placement of a fabrication substrate  14  onto the support member  12  may be facilitated while the liquid container  36  is in the first position, and capture of the liquid  24  spun off of the fabrication substrate  14  by the liquid container  36  may be facilitated while the liquid container  36  is in the second position during processing. 
   By way of example and not limitation, the system  10  may include a container actuator  46  such as, for example, an electromechanical device or motor, or a pneumatically or hydraulically actuated cylinder that is operatively coupled to a drive shaft  48 . The drive shaft  48  may be structurally coupled to the liquid container  36 . In this configuration, the container actuator  46  may be configured to selectively move the liquid container  36  in a vertical direction (as indicated by the directional arrow  50 ) back and forth between a first position in which the support member  12  is substantially disposed outside the liquid container  36  and a second position in which the support member  12  is substantially disposed inside the liquid container  36 . The liquid container  36  is shown in the second position in  FIG. 1 . 
   In additional embodiments, the rotatable support member  12  may be configured to move up and down in the vertical direction relative to the liquid container  36  instead of, or in addition to, the liquid container  36  being configured to move up and down in the vertical direction as previously discussed. Furthermore, the rotatable support member  12  and the liquid container  36  may be stationary relative to one another. 
   Optionally, an outer housing  54  may be used to substantially enclose the various components of the system  10 . 
   The system  10  also may include a computer device such as, for example, a programmable logic controller  58  or other electronic controlling device including, for example, at least one processor operably coupled to communicate with at least some of the active, controllable elements or components of the system  10 . By way of example and not limitation, the programmable logic controller  58  may communicate with and be configured to selectively control the liquid dispenser actuators  26  for moving the streams of liquid  24  dispensed by the liquid dispensers  22 , the flow control valves  32 , the rotation actuator device  16  for rotating or spinning the support member  12 , and the container actuator  46  for moving the position of the liquid container  36 . The programmable logic controller  58  also may communicate with and be configured to selectively control other active, controllable elements or components of the system  10  that are not shown in  FIG. 1  or described herein. 
   In this configuration, the programmable logic controller  58  may be programmed by way of computer software or code to spin, rinse, and dry a fabrication substrate  14  in accordance with a method that embodies teachings of the present invention and facilitates rinsing and drying of a fabrication substrate  14  while minimizing or eliminating water marks or other residues or matter left behind on the surface of the fabrication substrate  14 . 
   In at least a portion of a processing sequence, the programmable logic controller  58  may be programmed to continuously rotate, or spin, a fabrication substrate  14  about the rotational axis  20  while directing at least one stream of liquid  24  onto a contact area  62  on the surface  15  of the fabrication substrate  14 . Referring to  FIG. 2A  in combination with  FIG. 1 , the programmable logic controller  58  may be programmed to cause at least one liquid dispenser  22  to direct a stream of liquid  24  onto the surface  15  of the fabrication substrate  14  such that the contact area  62  is in a first, central position that includes an intersection between the surface  15  of the fabrication substrate  14  and the rotational axis  20 . This intersection between the surface  15  of the fabrication substrate  14  and the rotational axis  20  (see  FIG. 1 ) may define a center of rotation  21  on the surface  15  of the substrate  14 , illustrated in  FIGS. 2A-2D . The surface  15  of the fabrication substrate  14  may be substantially covered by a sheet or film of the liquid  24  dispensed from the liquid dispenser  22  ( FIG. 1 ) as the liquid  24  flows from the contact area  62  in a radially outward direction toward the peripheral edges  34  (e.g., circumference) of the fabrication substrate  14 . In this manner, the liquid  24  rinses the surface  15  of the fabrication substrate  14 . Optionally, at least one additional stream of liquid  24  may be directed onto one or more additional contact areas on the surface  15  of the surface of the fabrication substrate  14 , as discussed in further detail below. 
   Referring to  FIG. 2B  in combination with  FIG. 1 , the programmable logic controller  58  may be programmed to move the liquid dispenser  22  (while continuing to dispense liquid  24  from the liquid dispenser  22 ) such that the contact area  62  moves in a radially outward direction from the first position shown in  FIG. 2A  to a second position shown in  FIG. 2B  to form a substantially circular, substantially dry region  68  on the surface  15  of the fabrication substrate  14  that is centered about the rotational axis  20 . 
   In this second position shown in  FIG. 2B , the contact area  62  does not include the center of rotation  21 . The contact area  62  may be moved in a radially outward direction from the first position shown in  FIG. 2A  to the second position shown in  FIG. 2B  by a distance at which an outer periphery  63  of the contact area  62  is separated from the rotational axis  20  by a distance X 1  that is illustrated in  FIG. 2B . A substantially continuous annular-shaped sheet or film of liquid  24  may cover the regions on the surface  15  of the fabrication substrate  14  surrounding the substantially circular, substantially dry region  68  as the liquid  24  flows from the contact area  62  in a radially outward direction toward the peripheral edges  34  of the fabrication substrate  14 . The substantially continuous annular-shaped sheet or film of liquid  24  may have an inner diameter  72  that defines a void in the sheet or film of liquid  24  through which the substantially circular, substantially dry region  68  on the surface  15  of the fabrication substrate  14  is exposed. 
   By forming the substantially circular dry region  68 , the liquid  24  in the annular-shaped sheet or film of liquid  24  may be more readily spun off from the surface  15  of the fabrication substrate  14  relative to liquid  24  in a substantially continuous sheet or film substantially covering the surface  15  of the fabrication substrate  14 . Any finite area or region of liquid  24  on the surface  15  of a spinning fabrication substrate  14  may be subjected to both centrifugal forces and surface tension forces exerted on the area or region of liquid  24  by the surrounding liquid  24 . A finite area or region of liquid  24  located on the surface  15  of the fabrication substrate  14  may be subjected to surface tension forces by a portion of liquid  24  on the surface  15  of the fabrication substrate  14  radially inward thereof, relative to the rotational axis  20 . These surface tension forces may work against the centrifugal forces acting on the finite area or region of liquid  24 . By forming the substantially circular substantially dry region  68 , the surface tension acting on the liquid  24  that directly counteracts the centrifugal forces may be minimized or eliminated, thereby facilitating removal of the liquid  24  from the surface  15  of the fabrication substrate  14  by the centrifugal forces. 
   As a non-limiting example, the distance X 1  may be greater than about five percent (5%) of the distance across the surface  15  of the semiconductor fabrication substrate  14  (e.g., the diameter D shown in  FIG. 2A ). Accordingly, the inner diameter  72  of the annular-shaped sheet or film of liquid  24  may be greater than about ten percent (10%) of the distance across the surface  15  of the semiconductor fabrication substrate  14  (e.g., the diameter D shown in  FIG. 2A ). 
   As the contact area  62  is moved from the first position shown in  FIG. 2A  to the second position shown in  FIG. 2B , droplets of liquid  24  may splash onto the regions of the surface  15  of the fabrication substrate  14  radially inward from the contact area  62  (i.e., on the substantially circular, substantially dry region  68 ). These droplets of liquid  24  may leave water marks, residue, or other unwanted matter on the surface  15  of the fabrication substrate  14 . To minimize deposition of such water marks, residue, or other unwanted matter on the surface  15  of the fabrication substrate  14  by these droplets, the programmable logic controller  58  may be programmed to cause the liquid dispenser  22  or dispensers  22  to move the contact area  62  radially inward from the second position shown in  FIG. 2B  to a third position shown in  FIG. 2C  that is radially between the first position shown in  FIG. 2A  and the second position shown in  FIG. 2B , thereby reducing (but not eliminating) the diameter of the substantially circular, substantially dry region  68  and the inner diameter  72  of the annular-shaped sheet or film of liquid  24 . In the third position shown in  FIG. 2C , the outer periphery  63  of the contact area  62  may be separated from center of rotation  21  by a distance X 2  that is illustrated in  FIG. 2C . Thus, the contact area  62  does not include the center of rotation  21  in the third position shown in  FIG. 2C . 
   It may be desirable to provide a distance X 2  that is as small as possible without causing the liquid  24  to cover the center of rotation  21  and forming a substantially continuous sheet of liquid  24  that substantially covers the surface  15  of the fabrication substrate  14 . By way of example and not limitation, the distance X 2  shown in  FIG. 2C  may be less than about five percent (5%) of the distance across the surface  15  of the fabrication substrate  14  (e.g., the diameter D shown in  FIG. 2A ), and, accordingly, the inner diameter  72  of the annular-shaped sheet or film of liquid  24  may be less than about ten percent (10%) of the distance across the surface  15  of the fabrication substrate  14  (e.g., the diameter D shown in  FIG. 2A ). Furthermore, the diameter of the substantially circular, substantially dry region  68  and the inner diameter  72  of the annular-shaped sheet or film of liquid  24  may be less than about one centimeter (1 cm) in the third position shown in  FIG. 2C . 
   If the contact area  62  is moved from the first position shown in  FIG. 2A  directly to the third position shown in  FIG. 2C , the surface tension of the liquid  24  may prevent the formation of the relatively smaller substantially circular dry region  68  shown in  FIG. 2C . Therefore, the contact area  62  may be moved from the first position shown in  FIG. 2A  to the second position shown in  FIG. 2B  by a distance that is large enough to cause formation of the substantially circular dry region  68 . The contact area  62  may then be moved to the third position shown in  FIG. 2C , at which the size of the substantially circular dry region  68  may be minimized without causing the liquid  24  to substantially cover the surface  15  of the fabrication substrate  14  (entirely removing the substantially circular, substantially dry region  68 ). Moreover, as the contact area  62  is moved from the first position shown in  FIG. 2A  to the second position shown in  FIG. 2B , droplets of liquid  24  may be spattered or sprayed or otherwise deposited onto the substantially circular, substantially dry region  68 . By moving the contact area  62  from the second position shown in  FIG. 2B  to the third position shown in  FIG. 2C , these droplets of liquid  24  may be captured by or incorporated into the annular-shaped sheet or film of liquid  24 , thereby facilitating complete removal of the liquid  24  from the surface  15  of the fabrication substrate  14 . 
   The programmable logic controller  58  may be programmed to cause the liquid dispensers  22  to direct a stream of liquid  24  toward the first position shown in  FIG. 2A , the second position shown in  FIG. 2B , and the third position shown in  FIG. 2C  for predetermined amounts of time ranging from about zero seconds to several minutes or longer, as necessary or desired. 
   After the liquid dispensers  22  have been caused to position the contact area  62  of a stream of liquid  24  in the third position shown in  FIG. 2C , contact between the stream of liquid  24  impinging on the contact area  62  and the surface  15  of the fabrication substrate  14  may be interrupted while continuing to spin the fabrication substrate  14  to remove the liquid  24  from the surface  15  of the fabrication substrate  14 . For example, the programmable logic controller  58  may be configured to close one or more flow control valves  32  after the liquid dispensers  22  have positioned the contact area  62  in the third position shown in  FIG. 2C . As the fabrication substrate  14  continues to spin after interrupting the stream of liquid  24  impinging on the contact area  62 , the inner diameter  72  of the annular-shaped sheet or film of liquid  24  may progress in a radially outward direction towards the peripheral edge  34  (e.g., circumference) of the fabrication substrate  14 , as indicated by the directional arrows  74  in  FIG. 2D , until substantially all the liquid  24  has been spun off of the surface  15  of the fabrication substrate  14 . In other embodiments, the contact area  62  may be moved from the third position shown in  FIG. 2C  in a radially outward direction towards and beyond the peripheral edge  34  of the fabrication substrate  14  instead of closing one or more flow control valves  32  to interrupt the flow of liquid  24  onto the contact area  62 . 
   By way of example and not limitation, the fabrication substrate  14  may be spun at a rate greater than about 500 revolutions per minute while directing a stream of liquid  24  onto the surface  15  of the fabrication substrate  14 . More particularly, the fabrication substrate  14  may be spun at a rate of greater than about 4,000 revolutions per minute while directing a stream of liquid  24  onto the surface  15  of the fabrication substrate  14 . Furthermore, the fabrication substrate  14  may be spun at a rate or rates greater than about 2,000 revolutions per minute while the contact area  62  is in each of the first position shown in  FIG. 2A , the second position shown in  FIG. 2B , and the third position shown in  FIG. 2C , and at a rate or rates between about 500 revolutions per minute and about 1,000 revolutions per minute after interrupting contact between the stream of liquid  24  impinging on the surface  15  of the fabrication substrate  14  at the contact area  62 . In general, an optimum rate of rotation may be at least partially a function of the size of the fabrication substrate  14 , with smaller fabrication substrates  14  possibly requiring greater rates of rotation. 
   Optionally, at least one additional stream of liquid  24  may be directed onto the surface  15  of the fabrication substrate  14 . For example, as liquid  24  spreads out across the surface  15  of the fabrication substrate  14 , voids in the sheet or film of liquid  24  may occur near the peripheral edges  34  of the fabrication substrate  14 . Such voids may contribute to the deposition of water marks, residue, or other unwanted matter on the surface  15  of the fabrication substrate  14 , and may be undesirable. Referring to  FIG. 3A  in combination with  FIG. 1 , the programmable logic controller  58  may be programmed to concurrently direct at least one additional stream of liquid  24  onto at least one additional contact area  64  on the surface  15  of the fabrication substrate  14  to prevent or reduce the occurrence of voids in the sheet or film of liquid  24  near the peripheral edges  34  of the fabrication substrate  14 . 
     FIGS. 3A-3D  are similar to  FIGS. 2A-2D  respectively, and illustrate the use of an additional stream of liquid  24  to rinse the surface  15  of the fabrication substrate  14  to prevent or minimize the occurrence of voids in the sheet or film of liquid  24  proximate the peripheral edges  34  of the fabrication substrate  14 . Referring to  FIG. 3A , the programmable logic controller  58  may be programmed to cause at least one liquid dispenser  22  to direct a stream of liquid  24  onto an additional contact area  64  on the surface  15  of the fabrication substrate  14 . The second contact area  64  may be positioned on the surface  15  of the fabrication substrate  14  so as not to include or cover the center of rotation  21 . 
   As illustrated in  FIGS. 3A-3C , the additional stream of liquid  24  may be directed onto the surface  15  of the fabrication substrate  14  while the first contact area  62  is in one or more of the first position shown in  FIG. 3A , the second position shown in  FIG. 3B , and the third position shown in  FIG. 3C . The additional stream of liquid  24  may be directed onto the surface  15  of the fabrication substrate  14  while the first contact area  62  is in each of the first position shown in  FIG. 3A , the second position shown in  FIG. 3B , and the third position shown in  FIG. 3C . Additionally, the additional liquid  24  may be directed onto the surface  15  of the fabrication substrate  14  while the first contact area  62  is in only the second position shown in  FIG. 3B  and the third position shown in  FIG. 3C , or only while the first contact area  62  is in the third position shown in  FIG. 3C . Furthermore, the position of the additional contact area  64  on the surface  15  of the fabrication substrate  14  may vary as the first contact area  62  moves between the first position shown in  FIG. 3A , the second position shown in  FIG. 3B , and the third position shown in  FIG. 3C . 
   As shown in  FIG. 3A , the fabrication substrate  14  may have a diameter D. By way of example and not limitation, an outer periphery  65  of the second contact area  64  may be separated from the rotational axis  20  by a distance X 3  that is greater than about fifty percent (50%) of the diameter D ( FIG. 2A ) of the fabrication substrate  14  while the first contact area  62  is in the first position shown in  FIG. 3A , the second position shown in  FIG. 3B , and the third position shown in  FIG. 3C . 
   As shown in  FIG. 3D , a stream of liquid  24  may continue to be directed onto the additional contact area  64  until the inner diameter  72  of the annular-shaped sheet or film of liquid  24  approaches or reaches the additional contact area  64  after closing a flow control valve  32  to interrupt the stream of liquid  24  being directed at the first contact area  62  of the surface  15  of the fabrication substrate  14 . As the inner diameter  72  of the annular-shaped sheet or film of liquid  24  approaches or reaches the outer periphery  65  of the additional contact area  64 , the stream of liquid  24  being directed at or impinging on the additional contact area  64  on the surface  15  of the fabrication substrate  14  may also be interrupted while continuing to spin the fabrication substrate  14  until the liquid  24  has been substantially completely removed from the surface  15  of the fabrication substrate  14 . 
   In the systems and methods previously described in relation to  FIGS. 1 ,  2 A- 2 D, and  3 A- 3 D, the contact area  62  is moved relative to the surface  15  of the fabrication substrate  14  along a substantially linear path disposed along a line that includes the center of rotation  21 . As an alternative or in addition, the contact area  62  may be moved relative to the surface  15  of the fabrication substrate  14  along a curved or curvilinear path or any other nonlinear path. 
   Another embodiment of a liquid dispenser  76  is shown in  FIG. 4A  that may be used in the system  10  shown in  FIG. 1 . The liquid dispenser  76  may be configured to dispense a stream of liquid  24  in a lateral or horizontal direction relative to the surface  15  of the fabrication substrate  14 , as shown in  FIG. 4A . By way of example and not limitation, the liquid dispenser  76  may include a tube or conduit portion  78  and an outlet portion  80  configured to dispense a stream of liquid  24  in a lateral direction relative to the surface  15  of the fabrication substrate  14 . The liquid  24  may fall onto a contact area  62  on the surface  15  of the fabrication substrate  14  that is laterally spaced from the liquid dispenser  76 , as shown in  FIG. 4A . In this configuration, the position of the contact area  62  may be selectively moved across the surface  15  of the fabrication substrate  14  by, for example, rotating the liquid dispenser  76  about a dispenser axis  86 . Referring the  FIG. 4B , in such a configuration, the contact area  62  may be moved to a first position, from the first position to a second position, and from the second position, to a third position in accordance with the method described in reference to the first contact area  62  shown in  FIGS. 2A-2C , by selectively rotating the liquid dispenser  76  about the dispenser axis  86 . 
   The liquid dispenser  76  is shown in  FIG. 4B  rotated to a position about the dispenser axis  86  such that the contact area  62  is disposed in a first position that includes or covers the center of rotation  21 . In at least a portion of a processing sequence, a programmable logic controller  58  ( FIG. 1 ) may be programmed to rotate the liquid dispenser  76  about the dispenser axis  86  from the first position to a second position  88  such that the contact area  62  moves in a radially outward direction from the first position to a second position  90  to form a substantially circular, substantially dry region on the surface  15  of the fabrication substrate  14  having an outer diameter approximately represented by dashed line  92 . Moreover, the programmable logic controller  58  ( FIG. 1 ) may be programmed to rotate the liquid dispenser  76  about the dispenser axis  86  from the second position  88  to a third position  94  such that the contact area  62  moves in a radially inward direction from the second position  90  to a third position  96  to reduce the diameter of the substantially circular, substantially dry region to a size approximately represented by dashed line  98 . 
   In this manner, the liquid dispenser  76  may be selectively rotated or moved about the dispenser axis  86  to selectively move the contact area  62  to a first position including the center of rotation  21 , from the first position radially outward to a second position  90 , and from the second position  90  radially inward to a third position  96  in accordance with the method previously described in reference to  FIGS. 2A-2C . 
   In the systems and methods previously described herein, the contact area  62  is moved relative to the surface  15  of the fabrication substrate  14  by moving the position of the one or more liquid dispensers  22 ,  76  relative to the surface  15  of the fabrication substrate  14 . In other examples of systems and methods that embody teachings of the present invention, the contact area  62  may be moved relative to the surface  15  of the fabrication substrate  14  by means other than a moveable liquid dispenser  22 ,  76 . 
   For example, the system  10  ( FIG. 1 ) may include a liquid dispenser  99  as shown in  FIG. 5 , which may be configured to have a size and shape similar to the liquid dispenser  76  shown in  FIG. 4A . The liquid dispenser  99  may be positioned relative to the surface  15  of the fabrication substrate  14  radially outward from the center of rotation  21 , and oriented such that an outlet portion  80  of the liquid dispenser  99  directs a stream of liquid  24  (not shown in  FIG. 5 ) emitted thereby in a radially inward direction toward the center of rotation  21 . In such a configuration, the liquid dispenser  99  may be configured to selectively vary the position of the contact area  62  between the stream of liquid  24  and the surface  15  of the fabrication substrate  14  by selectively varying the pressure of the liquid  24  inside the liquid dispenser  76 . The system  10  ( FIG. 1 ) may include a selectively variable pressure control valve (not shown) in or along the fluid liquid supply lines  30 , and the programmable logic controller  58  may communicate with and be configured to selectively control the selectively variable pressure control valve. 
   In this configuration, the programmable logic controller  58  ( FIG. 1 ) may be programmed to vary the pressure of the liquid  24  inside the liquid dispenser  99 , thereby selectively moving the contact area  62  on the surface  15  of the fabrication substrate  14 . The programmable logic controller  58  may be programmed to move the contact area  62  (by varying the pressure of the liquid  24  in the liquid dispenser  99 ) to a first position that includes the center of rotation  21  (which may allow liquid  24  to substantially cover the surface  15  of the fabrication substrate  14 ), from the first position radially outward to a second position  100 , and from the second position  100  radially inward to a third position  102 , in a manner substantially similar to those previously described in reference to  FIGS. 2A-2D . As such, it may not be necessary to displace (e.g., move or rotate) the liquid dispenser  99  relative to the surface  15  of the fabrication substrate  14  in order to move the contact area  62  according to methods that incorporate teachings of the present invention. 
   Each of the methods described herein includes forming a substantially continuous annular-shaped sheet or film of liquid  24  on the surface  15  of a spinning fabrication substrate  14 , the annular-shaped sheet or film of liquid  24  having an inner diameter  72  defining a void in the sheet or film of liquid  24 , as well as reducing the size of the inner diameter  72  of the annular-shaped sheet or film of liquid  24 , then subsequently enlarging the inner diameter  72  of the annular-shaped sheet or film of liquid  24  until substantially no liquid  24  remains on the surface  15  of the fabrication substrate  14 . 
   In any of the previously described systems and methods, a stream of air or gas (such as, for example, clean dry air, nitrogen or another inert gas, etc.) may be directed at the surface  15  of the fabrication substrate  14  to facilitate the formation of a substantially circular, substantially dry region, such as the substantially circular, substantially dry region  68  shown in  FIGS. 2B-2D . Referring to  FIGS. 2A and 2B , and by way of example and not limitation, a stream of air or gas may be directed at the surface  15  of the fabrication substrate  14  at or proximate to the center of rotation  21  of the fabrication substrate  14  as the contact area  62  is moved from the first position shown in  FIG. 2A  to the second position shown in  FIG. 2B . The stream of air or gas may continue to be directed at the surface  15  of the fabrication substrate  14  while the contact area  62  is in the second position shown in  FIG. 2B , the third position shown in  FIG. 2C , and until the liquid  24  has been substantially removed from the surface  15  of the fabrication substrate  14  after interrupting the flow of liquid  24  onto the contact area  62 . 
   The inventors of the present invention have discovered, however, that by moving a contact area  62  in the manners and sequences previously described herein, the deposition of water marks, residue, or other unwanted matter on the surface  15  of a fabrication substrate  14  may be substantially minimized or eliminated. In this manner, the methods and systems of the present invention may facilitate rinsing and drying of a fabrication substrate while minimizing the deposition of water marks, contaminant residue, or other unwanted matter onto the surface of the substrate. Furthermore, methods and systems that embody teachings of the present invention may allow the liquid to be removed from the surface of a fabrication substrate faster than conventional methods and systems, and as a result, may reduce the amount of time required to dry semiconductor substrates. For example, methods and systems that embody teachings of the present invention may allow the liquid to be removed from the surface of a fabrication substrate up to twenty-percent (20%) faster than conventional methods and systems. 
   While systems that embody teachings of the present invention have been described in relation to what are referred to as spin, rinse, and dry (SRD) systems, the teachings of the present invention may be equally applicable to other semiconductor fabrication processes and systems in which a liquid is dispensed onto and removed from at least one surface of a spinning fabrication substrate. This may be particularly so in fabrication processes that involve liquids in which the surface tension of the liquid affects the removal of the liquid from the surface of the spinning fabrication substrate. By way of example and not limitation, wet etch systems and chemical-mechanical polishing (CMP) systems may also embody teachings of the present invention. As such, liquids dispensed from systems that embody teachings of the present invention may include clean de-ionized water, acids, solvents, or any other single- or multi-component liquid, solution, suspension or emulsion. 
   While the present invention has been described in terms of certain illustrated embodiments and variations thereof, it will be understood and appreciated by those of ordinary skill in the art that the invention is not so limited. Rather, additions, deletions and modifications to the illustrated embodiments may be effected without departing from the spirit and scope of the invention as defined by the claims which follow.