Abstract:
A low-cost approach to near field nano-scale photolithography using a plasmonic head with hydrostatic gas bearings. The hydrostatic gas bearing flies the plasmonic head at less than 100 nm, and more preferably less than 50 nm, above the photo-resist without the need to spin the substrate. The plasmonic head concentrates short-wavelength surface plasmons into about sub-100 nm regions on the photo-resist and can pattern features of about 80 nm or less.

Description:
RELATED APPLICATIONS 
       [0001]    The present application claims the benefit of U.S. Provisional Patent Application Ser. No. 61/172,685 entitled Plasmon Head with Hydrostatic Gas Bearing for Near Field Photolithography, filed Apr. 24, 2009. 
     
    
     FIELD OF THE INVENTION 
       [0002]    This invention relates to plasmonic heads with hydrostatic gas bearings for near field nano-scale photolithography. 
       BACKGROUND OF THE INVENTION 
       [0003]    The continuing size reduction of integrated circuits to nanometer (nm) scale dimensions requires the development of new lithographic techniques. The ultimate resolution of conventional photolithography is restricted by the diffraction limit. It is becoming increasingly difficult and complex to use the established method of optical projection lithography at the short optical wavelengths required to reach the desired feature sizes. For example, the use of wavelengths in the deep ultraviolet, the extreme ultraviolet (EUV), or the X-ray regime requires increasingly difficult adjustments of the lithographic process, including the development of new light sources, photo-resists, and optics. 
         [0004]    U.S. Pat. Publication No. 2003/0129545 (Kik et al.) discloses a method for performing nanolithography using a photo-mask with conductive nanostructures disposed thereon. The nanostructures have a plasmon resonance frequency that is determined by the dielectric properties of the surroundings and of the nanostructures, as well as the nanostructure shape. The nanostructures are illuminated with light at or near the frequency of the plasmon resonance frequency, which causes collective oscillations of the electrons at the surface of the nanostructure. These oscillations can have wavelengths that are much shorter than the wavelength of the light that excited them, which are sufficient to modify adjacent portions of the resist layer. The resist layer is developed to create plasmon printed, subwavelength patterns. Creating the photo-mask, however, is time intensive, expensive, and does not easily permit design changes. 
         [0005]    The commercialization of nanoscale devices requires the development of high-throughput nanofabrication technologies that allow frequent design changes. Maskless nanolithography, including electron-beam and scanning-probe lithography, offers the desired flexibility, but is limited by low throughput and extremely high cost. 
         [0006]    U.S. Pat. Publication No. 2007/0069429 (Albrecht et al.) is directed to a system and method for patterning a master disk to be used for nanoimprinting magnetic recording disks. An air-bearing created by a rotating master disk substrate supports a slider with an aperture structure within the optical near-field of a resist layer. The fly height of the slider is typically about 10 to about 20 nanometers. A liquid lubricant and/or a protective film, such as a carbon film, may be provided on the resist layer to improve the flyability of the slider supporting the plasmonic head. The timing of the laser pulses is controlled to form a pattern of exposed regions in the resist layer, with this pattern ultimately resulting in the desired pattern of data islands and non-data islands in a magnetic recording disks when they are nanoimprinted by the master disk. 
         [0007]    The spinning master disk of Albrecht is essential to establish the air bearing between the slider and the photo-resist. The spinning master disk, however, is subject to vibration and spindle run-out errors that lead to patterning errors and potential collisions between the slider and the photo-resist. Roughness of the photo-resist and media needs to be closely controlled to enable the slider to fly without crashing. If the plasmonic lens contacts the master disk it can be coated with photo-resist, potentially smearing the lens and causing patterning errors. Finally, a spinning master disk is not a practical method of making more complex structures, such as for example micro electrical mechanical systems (MEMS). 
       BRIEF SUMMARY OF THE INVENTION 
       [0008]    The present invention is directed to a low-cost approach to near field nano-scale photolithography using a plasmonic head with hydrostatic gas bearings. The hydrostatic gas bearing flies the plasmonic head at less than 100 nm, and more preferably less than 50 nm, above the photo-resist without the need to spin the substrate. The plasmonic head concentrates short-wavelength surface plasmons into about sub-100 nm regions on the photo-resist and can pattern features of about 80 nm or less. This nanofabrication system has the potential to provide desktop, maskless nanophotolithography at several orders of magnitude lower cost than current maskless techniques. Nano-scale typically refers to features with dimensions of less than one micrometer (1×10 6  meters). 
         [0009]    At least one plasmonic head is preferably located at the trailing edge of the slider. Alternatively, one or more lenses are mounted on the slider. For commercial applications, a plurality of plasmonic heads are provided on each slider. 
         [0010]    The slider is supported by a suspension assembly fabricated with air channels connected to an external air supply. The channels are fluidly coupled to openings in the air bearing surface of the slider. In one embodiment, channels are etched in the suspension assembly and a polyamide cover is applied over the channels to form gas conduits. The channels can be on the top or the bottom of the suspension assembly. 
         [0011]    The hydrostatic gas bearing provides a controlled clearance between the substrate and the slider. The clearance is maintained by externally pressurizing a plurality of pads located on the air bearing surface of the slider in proximity with the substrate. Once the desired clearance is attained between the hydrostatic slider and the substrate, a laser is directed at a near field transducer located on the slider. The resulting emission from the near field transducer exposes the photo-resist. 
         [0012]    In one embodiment, the externally pressurized gas bearing design allows for independently controlling the pressure on each pad of the hydrostatic bearing. Independent control of each gas port permits the pitch and roll of the slider to be adjusted to optimize the photolithographic process. 
         [0013]    The clearance of the slider is preferably calibrated ex-situ on an optical fly height tester prior to usage. Each hydro-static pad pressure is calibrated to assure a near field gap. A sensor is preferably provided on the slider to monitor flying height. Heaters may also be provided adjust the position of the plasmonic head relative to the photo-resist. 
         [0014]    The system includes an X-Y stage to accurately locate a substrate relative to the slider. A controller operating the X-Y stage and the laser assembly accurately expose the photo-resist to form the desired pattern. Since the substrate is not required to spin to maintain a gas bearing, transfer of vibration and spindle run-out errors to the pattern are minimized. 
         [0015]    Micro electro mechanical systems (MEMS) methods are well suited for fabricating the present hydrostatic slider. For example, a silicon wafer is patterned with the gas bearing features. A series of through holes for the gas ports are machined with a deep reactive ion etch process (DRIE) or simply machined. Once the silicon wafers are patterned and fabricated, a series of slider bars are sliced to expose the slider sides for further processing. A thick dielectric such as alumina is sputtered at the end of slider. A planar solid immersion mirror with a dual offset grating used to focus a waveguide mode onto the near-field transducer (NFT) is fabricated onto the trailing edge of the slider. 
         [0016]    The photolithography system includes a head suspension assembly with a load beam having a flexure at a distal end and a plurality of channels. A covering layer extends over the channels to form gas conduits. The slider includes a first surface attached to the flexure and a second surface facing the substrate. The first surface of the slider includes a plurality of ports fluidly coupled to the gas conduits. The ports extend through the slider and exit through holes in at least one air bearing surface located on the second surface. A near field assembly on the slider emits radiation onto a region of the photo-resist in response to incident radiation. The region has a maximum dimension of less than about 100 nanometers. A laser assembly supplies the incident radiation. A source of pressurized gas delivered to the gas conduits maintains a clearance between the near field assembly and the photo-resist layer of less than about 100 nanometers. A controller synchronizes activation of the laser assembly with the position of the substrate relative to the near field assembly to form the desired pattern on the photo-resist layer. 
         [0017]    The substrate can be one or more of flexible, rigid, planar, non-planar, or cylindrical. The laser assembly supplies radiation at a first wavelength and the near field assembly emits radiation at a second shorter wavelength in response to incident radiation. The region of radiation emitted onto the photo-resist has a maximum dimension of less than about 80 nanometers, and preferably a maximum dimension of less than about 60 nanometers. 
         [0018]    The pattern has features with sizes less than about a wavelength of the incident radiation. The features are preferably less than about 50% of a wavelength of the incident radiation, and more preferably less than about 20%. 
         [0019]    The slider preferably includes a sensor monitoring the clearance between the near field assembly and the photo-resist layer. The clearance between the near field assembly and the photo-resist layer of less than about 50 nanometers, and more preferably less than about 20 nanometers. 
         [0020]    The present invention is also directed to a plasmonic head for near field photolithography. 
         [0021]    The present invention is also directed to a method for forming a pattern in photo-resist layer on a substrate using a photolithography system. A pressurized gas is delivered through conduits in a head suspension to ports on a slider. The pressurized gas is ejected from the ports in the slider to create a hydrostatic gas bearing with a clearance between a near field assembly and a photo-resist layer of less than about 100 nanometers. Incident radiation is directed from a laser assembly to the near field assembly. A region of radiation with a maximum dimension of less than about 100 nanometers is emitted from the near field assembly onto the photo-resist in response to the incident radiation. Activation of the laser assembly is synchronized with a position the substrate relative to the near field assembly to form the pattern. 
     
    
     
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING 
         [0022]      FIG. 1  is a schematic illustration of a maskless, nano-photolithography system with a hydrostatic gas bearing in accordance with an embodiment of the present invention. 
           [0023]      FIG. 2A  illustrates a near field assembly formed on an edge of a slider in accordance with an embodiment of the present invention. 
           [0024]      FIG. 2B  is a perspective view of the slider of  FIG. 2A . 
           [0025]      FIG. 2C  is a schematic illustrate of an alternate near field transducer in accordance with an embodiment of the present invention. 
           [0026]      FIG. 3  is an exploded view of a head suspension in accordance with an embodiment of the present invention. 
           [0027]      FIG. 4  is a top view of the head suspension of  FIG. 3 . 
           [0028]      FIG. 5  is a bottom exploded view of the head suspension of  FIG. 3 . 
           [0029]      FIG. 6  is a perspective view of an alternate head suspension in accordance with an embodiment of the present invention. 
           [0030]      FIG. 7  is a bottom view of the slider of  FIG. 6 . 
           [0031]      FIG. 8  is a schematic illustration of a maskless nanophotolithography system with a hydrostatic gas bearing for use with a non-planar substrate in accordance with an embodiment of the present invention. 
           [0032]      FIG. 9  is a schematic illustration of a maskless nanophotolithography system with a hydrostatic gas bearing for use with a flexible substrate in accordance with an embodiment of the present invention. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0033]    The entire content of U.S. Provisional Patent Application Ser. No. 61/172,685, filed Apr. 24, 2009, is hereby incorporated by reference. 
         [0034]      FIG. 1  is a schematic illustration of the system  50  for maskless, nano-scale, photolithography in accordance with an embodiment of the present invention. A master  52  including a substrate  54  with photo-resist layer  56  supported on X-Y stage  58 . Slider  60  has an air-bearing surface (ABS)  62  that is oriented toward the master  52 . 
         [0035]    The slider  60  is mounted on a suspension  64  similar to a conventional suspension like that used in magnetic recording disk drives, with a head gimbal assembly or flexure  66  that permits the slider  60  to “pitch” and “roll” relative to the master  52 . The suspension  64  is connected to support arm  68  that is supported by controller  70 . The support aim  68  applies a preload to the suspension  64  to maintain the flying ability of the slider  60 . 
         [0036]    In one embodiment, the support arm  68  is fixedly mounted on controller  70 . In another embodiment, the support arm  68  is adapted to translate relative to the controller  70 . Translation can include linear movement in the X, Y, and/or Z directions, as well as rotation around a fixed point. For example, a linear actuator can move the support arm  68  in the X-direction and/or Y-direction. Alternatively, a rotary actuator, such as a rotary voice-coil-motor (VCM) actuator, rotates the support arm  68  along a generally radial or arcuate path. 
         [0037]    The slider  60  includes a near field assembly  72  that directs radiation from laser assembly  74  to the resist layer  56 . The laser assembly  74  typically includes a laser, a modulator and one or more lenses. Alternatively, one or more lenses may be located on the slider  60 . The laser assembly  74  is supported by armature  76  attached to the controller  70 . In embodiments where the support arm  68  is permitted to translate relative to the controller  70 , the armature  76  preferably translates with the support arm  68  so that the position of the laser assembly  74  relative to the near field assembly  72  is maintained. The master  52  is movable relative to the slider  60  by X-Y stage  58 . 
         [0038]    Radiation  80  from the laser assembly  74  may be directed to the near field assembly  72  using a variety of techniques, such as for example the system disclosed in U.S. Pat. No. 5,497,359 or U.S. Pat. Publication 2007/0069429, which are hereby incorporated by reference. Alternatively, the radiation  80  from laser assembly  74  may be delivered to the near field assembly  72  by optical fibers. 
         [0039]    Most commonly used lasers are diode-pumped solid state lasers, e.g., Nd:YAG or Nd:YLF. These may be frequency multiplexed to give radiation at higher harmonics. For example a Nd:YAG laser with frequency multiplexing may be used to generate radiation at 1064 nm, 532 nm, 355 nm or 266 nm. Additionally, the radiation from the laser may be modulated using external modulators. Mode-locked lasers also provide rapid pulses with frequencies up to about 100 MHz. Other lasers such as pulsed diode lasers may also be used. 
         [0040]    The controller  70  can be a specialty computer, a conventional PC, or a combination thereof. The controller  70  is programmed with the desired pattern to be created in the photo-resist  56 . The control system  70  controls the X-Y stage  58  and activation of the laser assembly  74  to form the desired pattern in the resist layer  56  of master  52 . In another embodiment, the laser assembly  74  delivers pulses on demand, in response to a trigger signal. 
         [0041]      FIG. 2A  is an enlarged view of a near field assembly  102  located on a side surface of a slider  100  in accordance with one embodiment of the present invention. Planar solid immersion mirror  104  with dual offset gratings  106 A,  106 B focuses radiation  80  onto near field transducer  108 . The dual offset grating  106 A,  106 B are offset by half a wavelength of the radiation  80  causing a phase shift. The near field transducer  108  is located at the focus of the planar solid immersion mirror  104 . When the near field transducer  108  is excited to surface plasmon resonance, tip  110  couples the light into the photo-resist  56 . The tip  110  provides a lightning rod effect for field confinement. A near field assembly suitable for use in the present embodiment is disclosed in Challener, et al.  Heat - assisted Magnetic Recording by a Near - field Transducer with Efficient Optical Energy Transfer,  DOI: 10.1038 Nature Photonics (2009) and U.S. Pat. No. 7,272,079 (Challener), which are incorporated by reference. 
         [0042]    Surface plasmons (SPs) are collective oscillations of surface charge that are confined to an interface between a dielectric and a metal. When surface plasmons are resonantly excited by the external optical field  80 , the field amplitude of the output radiation  112  in the vicinity of the region  114  may be orders of magnitude greater than that of the incident radiation  80 . 
         [0043]    The region  114  of output radiation  112  is tightly confined, with a cross-sectional area much smaller than the incident wavelength  80 . The region  114  is typically circular or oval in shape, although a variety of other shapes are possible. The region  114  preferably covers an area with a major dimension of less than about 100 nanometers, and more preferably less than about 80 nanometers, and more preferably less than about 60 nanometers. 
         [0044]    The output radiation  112  from the near field transducer  108  heats the photo-mask  56  to form exposed regions  115  with different properties than the unexposed regions  119  of the photo-mask  56 . The exposed regions  115  are depicted as corresponding to the size of the region  114  created from a single laser pulse. The size of the exposed regions  115 , however, can be modified by varying the on-time of the laser, clearance  118 , and a variety of other factors. 
         [0045]    After exposure to heat from the output radiation  112 , the photo-resist  56  forms a new material different from the unexposed regions. By controlling the position of the master  52  and the pulses from the laser assembly  74 , the controller  70  can generate a predetermined pattern. The master  52  is then etched, such as by chemical etchants or reactive-ion-etching (RIE). The exposed regions  115  are resistant to the etching acting as a mask. The exposed regions  115  are resistant to hydrochloric acid mixtures (HCl:H.sub.2O.sub.2:H.sub.2O, 1:1:48) and nitric acid mixtures, while the unexposed regions  119  are removed in the same acid mixture. 
         [0046]    The etching is performed into the substrate  54  so that after removal of the remaining photo-resist  56 , the substrate  54  has the desired pattern features  121 . The present system permits features  121  with dimensions less than the wavelength of the incident radiation  80 . The features  121  preferably have a size less than about 50%, more preferably less than about 30%, and most preferably less than about 20%, of the wavelength of the incident radiation. The features  121  preferably have a maximum dimension of less than about 80 nanometers, and more preferably less than about 60 nanometers, and more preferably less than about 40 nanometers. 
         [0047]    Due to the exponential decay of the evanescent field of surface plasmons, the tightly focused region  114  only exists at the near field of the near field transducer  108 , normally less than about 100 nanometers. To achieve high-speed scanning, clearance  118  between distal end  116  of the tip  110  and surface  57  of the photo-resist  56  is preferably less than about 50 nanometers, and more preferably less than about 20 nanometers to about 10 nanometers, above the photo-resist layer  56 . 
         [0048]    As best illustrated in  FIG. 2B , distal end  116  of the tip  110  is flush with air bearing surface  130 C so that the clearance  118  is controlled by the gas bearing. In another embodiment, the tip  110  extends beyond the air bearing surface  130 C toward the master  52 . This embodiment permits the plasmon field to be closer to the photo-mask  56 , while maintaining a greater clearance between the slider  60  and the surface  57  of the photo-resist  56 . 
         [0049]      FIG. 2C  is a schematic illustrate of an alternate near field transducer  108 C in accordance with an embodiment of the present invention. Distal end  116 C includes pointed tip  110 C. The tip  110 C concentrates energy from the transducer  108 C. A variety of other shapes are possible for the tip  110 C, depending on the shape and size of the desired exposed regions  115  (see  FIG. 2A ). 
         [0050]    In some embodiments, the slider  100  may contain one or more heaters to control the position of the near field assembly  102  and/or the near field transducer  108  relative to the surface  57  of the photo-resist layer  56 . Various heater configurations and methods for controlling the position of the near field assembly  102  are disclosed in U.S. Pat. No. 5,991,113 (Meyer et al.); U.S. Pat. No. 7,428,124 (Song et al.); U.S. Pat. No. 7,430,098 (Song, et al.); and U.S. Pat. No. 7,388,726 (McKenzie et al.); U.S. Publication Nos. 2006/0285248 (Pust et al.) and 2007/0035881 (Burbank et al.); and U.S. application Ser. No. 12/424,441 (Boutaghou et al.), all of which are hereby incorporated by reference. 
         [0051]      FIGS. 3 through 5  illustrate a suspension assembly  200  capable of generating a hydrostatic gas bearing in accordance with an embodiment of the present invention. Stainless steel suspension  202  is etched to create channels  204 A,  204 B,  204 C,  204 D (collectively “ 204 ”). In the illustrated embodiment, distal ends of the channels  204  terminate in through holes  206 A,  206 B,  206 C,  206 D (collectively “ 206 ”). The through holes  206  are configured to align with ports  208 A,  208 B,  208 C,  208 D (collectively “ 208 ”) in slider  210 . 
         [0052]    While the illustrated embodiment includes four channels and four ports  208  in the slider  210 , a variety of other configurations are possible. In one embodiment, the channels  204 A and  204 B are combined into a single channel, as are  204 C and  204 D. As will be discussed herein, the number and/or the locations of ports  208  can also vary. In another embodiment, the channels  204  may be formed in the bottom surface of the suspension  202 , making the holes  206  unnecessary. 
         [0053]    Sealing layer  212  is located over the top of the channels  204  to form a substantially air-tight seal. In one embodiment, the sealing layer  212  is a polyamide sheet with a pressure sensitive adhesive on one surface. Pressurized gas can be delivered to the channels  204  from base plate  214  attached to load beam  216 . In one embodiment, a multi-layered polyamide sheet  215  delivers pressurized gas from the controller  70  to the base plate  214 . The polyamide sheet  215  includes conduits  217 A,  217 B,  217 C,  217 D (collectively “ 217 ”) fluidly coupled to through holes  228 A,  228 B,  228 C,  228 D in the base plate  214  and the load beam  216 . The pressurized gas travels down the respective channels  204  to flexure  218 , out through holes  206 , and into the ports  208  on the slider  210 . 
         [0054]    As best illustrated in  FIG. 5 , bottom surface  230  of the flexure  218  includes recesses  232  around the through holes  206 . These recesses  232  mate with the ports  208  on the top of the slider  210 . Each port  208  is fluidly coupled to a respective plurality of holes  234 A,  234 B,  234 C,  234 D (collectively “ 234 ”) formed in respective air bearing surfaces  236 A,  236 B,  236 C,  236 D (collectively “ 236 ”) on the base of the slider  210 . The pressurized gas exits these holes  234  to form a gas bearing between the slider  210  and the master  52 . 
         [0055]    The controller  70  monitors gas pressure delivered to the slider  60 . Gas pressure to each of the four channels  204  is preferably independently controlled so that the pitch and roll of the slider  60  can be adjusted. In another embodiment, the same gas pressure is delivered to each of the channels  204 . While clean air is the preferred gas, other gases such as for example argon may also be used. The gas pressure is typically in the range of about 2 atmospheres to about 4 atmospheres. 
         [0056]    The slider  210  includes an alternate near field assembly  250  in accordance with another embodiment of the present invention. The near field assembly  250  includes aperture  252  formed of a material, such as glass, quartz or another dielectric material, that is transmissive to radiation  80  at the wavelength of the laser assembly  74 . A film  254  of material substantially reflective to the radiation  80  at the wavelength of the laser assembly  74  is located on the disk-facing side  256  around the aperture  252 . The aperture  252  is preferably subwavelength-sized, i.e., its diameter if it is circularly-shaped or its smallest feature if it is non-circular, is less than the wavelength of the incident laser radiation  80  and preferably less than one-half the wavelength of the laser radiation  80 . A suitable near field assembly  250  is disclosed in U.S. Pat. Publication No. US 2007/0069429. 
         [0057]    Optical transmission through a subwavelength aperture in a metal film is enhanced when the incident radiation is resonant with surface plasmons at a corrugated metal surface  250  surrounding the aperture  252 . Thus features such as ridges or trenches in the metal film  250  serve as a resonant structure to further increase the emitted radiation output from the aperture  252  beyond what it would be in the absence of these features. The effect is a frequency-specific resonant enhancement of the radiation emitted from the aperture  252 , which is then directed onto the photo-resist  56  positioned within the near-field. This resonant enhancement is described by Thio et al.,  Enhanced Light Transmission Through A Single Subwavelength Aperture,  Optics Letters, Vol. 26, Issue 24, pp. 1972-1974 (2001) and in US 2003/0123335. 
         [0058]      FIGS. 6 and 7  illustrate the slider  100  of  FIGS. 2A and 2B  as part of a suspension assembly  120  in accordance with an embodiment of the present invention. Top surface  122  of the suspension  120  is etched to form three channels  124 A,  124 B, and  124 C (collectively “ 124 ”). The channels  124  terminate in through holes  126 A,  126 B,  126 C (collectively “ 126 ”) fluidly coupled to ports through the slider  100 . As best illustrated in  FIG. 7 , bottom surface  128  of the slider  100  includes three air bearing surfaces  130 A,  130 B, and  130 C, each with a plurality of holes  132  fluidly coupled to the channels  124 . The single pad  130 C near the near field assembly  102  optimizes the tracking of the tip  110  with the waviness of the master  52 . The four-pad design of  FIG. 5 , by contrast, averages the waviness of the master  52  across the entire lower surface of the slider  210 . 
         [0059]    The substrate  54  may be any suitable material, such as a wafer of single-crystal silicon. The photo-resist  56  is preferably a photo-resist that is generally insensitive to light with a wavelength greater than about 400 nm so that it can be handled in room light. The photo-resist is a material that changes its optical or chemical etching properties when heated by exposure to laser radiation. 
         [0060]      FIG. 8  is a schematic illustration of a maskless nanophotolithography system  300  with a hydrostatic gas bearing for use with non-planar substrates in accordance with an embodiment of the present invention. In the illustrated embodiment, the non-planar substrate  302  is a cylindrical roll  302  with a photo-resist layer  304 . 
         [0061]    Slider  306  is mounted on a suspension  308  with a head gimbal assembly or flexure that permits “pitch” and “roll” relative to the cylindrical roll  302 , as discussed above. Support arm  312  and/or controller  310  preferably translates in the X, Y, and/or Z directions relative to the cylindrical roll  302 . The cylindrical roll  302  also rotates around axis  314 . A rotary actuator optionally rotates the support arm  312  along a generally radial or arcuate path. Consequently, the slider  306  can be positioned anywhere on the surface of the cylindrical roll  302 . 
         [0062]    One or more near field assemblies located on the slider  306  selectively heats the photo-mask  304  to form the desired pattern. The cylindrical roll  302  is then etched to create the desired patterns. The cylindrical roll  302  can be the final article or can be used to imprint the pattern into another article. For example, the etched cylindrical roll  302  can be a negative used to transfer the pattern to another roll, planar substrate, flexible substrate, and the like. 
         [0063]      FIG. 9  is a schematic illustration of a maskless nanophotolithography system  350  with a hydrostatic gas bearing for use with a flexible substrate  352  in accordance with an embodiment of the present invention. The flexible substrate  352  can be a polymeric film, a metal foil, or a combination thereof, coated with a photo-resist layer. The flexible substrate  352  is positioned opposite slider  354  on roll  356 . The desired pattern is then formed directly onto a flexible substrate  352  as discussed herein. 
         [0064]    In one embodiment, a plurality of sliders are positioned along the length of the cylindrical roll to simultaneously form the desired pattern in the flexible cylindrical roll  302  or the flexible film  352 . 
         [0065]    Where a range of values is provided, it is understood that each intervening value, to the tenth of the unit of the lower limit unless the context clearly dictates otherwise, between the upper and lower limit of that range and any other stated or intervening value in that stated range is encompassed within the inventions. The upper and lower limits of these smaller ranges which may independently be included in the smaller ranges is also encompassed within the inventions, subject to any specifically excluded limit in the stated range. Where the stated range includes one or both of the limits, ranges excluding either both of those included limits are also included in the inventions. 
         [0066]    Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which these inventions belong. Although any methods and materials similar or equivalent to those described herein can also be used in the practice or testing of the present inventions, the preferred methods and materials are now described. All patents and publications mentioned herein, including those cited in the Background of the application, are hereby incorporated by reference to disclose and described the methods and/or materials in connection with which the publications are cited. 
         [0067]    The publications discussed herein are provided solely for their disclosure prior to the filing date of the present application. Nothing herein is to be construed as an admission that the present inventions are not entitled to antedate such publication by virtue of prior invention. Further, the dates of publication provided may be different from the actual publication dates which may need to be independently confirmed. 
         [0068]    Other embodiments of the invention are possible. Although the description above contains much specificity, these should not be construed as limiting the scope of the invention, but as merely providing illustrations of some of the presently preferred embodiments of this invention. It is also contemplated that various combinations or sub-combinations of the specific features and aspects of the embodiments may be made and still fall within the scope of the inventions. It should be understood that various features and aspects of the disclosed embodiments can be combined with or substituted for one another in order to form varying modes of the disclosed inventions. Thus, it is intended that the scope of at least some of the present inventions herein disclosed should not be limited by the particular disclosed embodiments described above. 
         [0069]    Thus the scope of this invention should be determined by the appended claims and their legal equivalents. Therefore, it will be appreciated that the scope of the present invention fully encompasses other embodiments which may become obvious to those skilled in the art, and that the scope of the present invention is accordingly to be limited by nothing other than the appended claims, in which reference to an element in the singular is not intended to mean “one and only one” unless explicitly so stated, but rather “one or more.” All structural, chemical, and functional equivalents to the elements of the above-described preferred embodiment that are known to those of ordinary skill in the art are expressly incorporated herein by reference and are intended to be encompassed by the present claims. Moreover, it is not necessary for a device or method to address each and every problem sought to be solved by the present invention, for it to be encompassed by the present claims Furthermore, no element, component, or method step in the present disclosure is intended to be dedicated to the public regardless of whether the element, component, or method step is explicitly recited in the claims.