Abstract:
A method for spreading a conformable material between a substrate and a template having a mold. The method comprises positioning the mold to be in superimposition with the substrate defining a volume therebetween. A first sub-portion of the volume is charged with the conformable material through capillary action between the conformable material and one of the mold and the substrate. A second sub-portion of the volume is filled with the conformable material by creating a deformation in the mold.

Description:
CROSS-REFERENCE TO RELATED PATENT APPLICATIONS  
       [0001]     The present application is a divisional patent application of U.S. patent application Ser. No. 11/292,568 (Attorney Docket Number P233), filed Dec. 1, 2005 and entitled “Technique for Separating a Mold from Solidified Imprinting Material,” and listing Mahadevan GanapathiSubramanian, Byung-Jin Choi, Michael N. Miller, and Nicholas A. Stacey as inventors, the entirety of which is incorporated by reference herein. 
     
    
     BACKGROUND OF THE INVENTION  
       [0002]     The field of invention relates generally to nano-fabrication of structures. More particularly, the present invention is directed to a method for improving contact imprinting employed in imprint lithographic processes.  
         [0003]     Nano-scale fabrication involves the fabrication of very small structures, e.g., having features on the order of one nanometer or more. A promising process for use in nano-scale fabrication is known as imprint lithography. Exemplary imprint lithography processes are described in detail in numerous publications, such as United States published patent application 2004/0065976 filed as U.S. patent application Ser. No. 10/264,960, entitled “Method and a Mold to Arrange Features on a Substrate to Replicate Features having Minimal Dimensional Variability”; United States published patent application  2004-0065252  filed as U.S. patent application Ser. No. 10/264,926, entitled “Method of Forming a Layer on a Substrate to Facilitate Fabrication of Metrology Standards”; and U.S. Pat. No. 6,936,194, entitled “Method and a Mold to Arrange Features on a Substrate to Replicate Features having Minimal Dimensions Variability”; all of which are assigned to the assignee of the present invention.  
         [0004]     Referring to  FIG. 1 , the basic concept behind imprint lithography is forming a relief pattern on a substrate that may function as, inter alia, an etching mask so that a pattern may be formed into the substrate that corresponds to the relief pattern. A system  10  employed to form the relief pattern includes a stage  11  upon which a substrate  12  is supported, and a template  14  having a mold  16  with a patterning surface  18  thereon. Patterning surface  18  may be substantially smooth and/or planar, or may be patterned so that one or more recesses are formed therein. Template  14  is coupled to an imprint head  20  to facilitate movement of template  14 . A fluid dispense system  22  is coupled to be selectively placed in fluid communication with substrate  12  so as to deposit polymerizable material  24  thereon. A source  26  of energy  28  is coupled to direct energy  28  along a path  30 . Imprint head  20  and stage  11  are configured to arrange mold  16  and substrate  12 , respectively, to be in superimposition, and disposed in path  30 . Either imprint head  20 , stage  11 , or both vary a distance between mold  16  and substrate  12  to define a desired volume therebetween that is filled by polymerizable material  24 . The relative positions of substrate  12  and stage  11  is maintained employing standard chucking techniques. For example, stage  11  may include a vacuum chuck, such as a pin chuck (not shown) coupled to a vacuum supply (not shown).  
         [0005]     Typically, polymerizable material  24  is disposed upon substrate  12  before the desired volume is defined between mold  16  and substrate  12 . However, polymerizable material  24  may fill the volume after the desired volume has been obtained. After the desired volume is filled with polymerizable material  24 , source  26  produces energy  28 , which causes polymerizable material  24  to solidify and/or cross-link, forming polymeric material conforming to the shape of the substrate surface  25  and mold surface  18 . Control of this process is regulated by processor  32  that is in data communication with stage  11  imprint head  20 , fluid dispense system  22 , and source  26 , operating on a computer-readable program stored in memory  34 .  
         [0006]     An important characteristic with accurately forming the pattern in polymerizable material  24  is to ensure that the dimensions of the features formed in the polymerizable material  24  are controlled. Otherwise, distortions in the features etched into the underlying substrate may result.  
         [0007]     A need exists, therefore, to improve the imprinting technique employed in contact lithographic processes.  
       SUMMARY OF THE INVENTION  
       [0008]     The present invention provides a method for spreading a conformable material between a substrate and a template having a mold. The method comprises positioning the mold to be in superimposition with the substrate defining a volume therebetween. A first sub-portion of the volume is charged with the conformable material through capillary action between the conformable material and one of the mold and the substrate. A second sub-portion of the volume is filled with the conformable material by creating a deformation in the mold. These and other embodiments are described herein. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0009]      FIG. 1  is a simplified plan view of a lithographic system in accordance with the prior art;  
         [0010]      FIG. 2  is a simplified plan view of a template and imprinting material disposed on a substrate in accordance with the present invention;  
         [0011]      FIG. 3  is a simplified plan view of the template and substrate, shown in  FIG. 2 , with the imprinting material being shown as patterned and solidified upon the substrate;  
         [0012]      FIG. 4  is a detailed view of the substrate shown in  FIGS. 2 and 3 , in accordance with the present invention;  
         [0013]      FIG. 5  is a detailed view of the substrate shown in  FIG. 4  having a solidified formation of imprinting material disposed thereon;  
         [0014]      FIG. 6  is a detailed view of the substrate shown in  FIG. 5  after being subjected to an etching chemistry to expose regions of the substrate;  
         [0015]      FIG. 7  is a detailed view of the substrate shown in  FIG. 6  after being subjected to an etch and removal of the solidified imprinting material;  
         [0016]      FIG. 8  is a cross-sectional view of a flexible template in accordance with the present invention;  
         [0017]      FIG. 9  is a cross-sectional view of the mold shown in  FIG. 8  imprinting polymerizable material disposed on the substrate shown in  FIG. 4 , in accordance with the present invention;  
         [0018]      FIG. 10  is a detailed view of the mold shown in  FIG. 9  before the same has conformed to a shape of the substrate;  
         [0019]      FIG. 11  is a detailed view of the substrate shown in  FIG. 9  after being subjected to an etching chemistry to expose regions of the substrate;  
         [0020]      FIG. 12  is a detailed view of the substrate shown in  FIG. 9  after being subjected to an etch and removal of the solidified imprinting material;  
         [0021]      FIG. 13  is a cross-sectional view of the flexible template shown in  FIG. 8 , in accordance with an alternate embodiment of the present invention;  
         [0022]      FIG. 14  is a cross-sectional view of the flexible template shown in  FIG. 8 , in accordance with a second alternate embodiment of the present invention;  
         [0023]      FIG. 15  is a cross-sectional view of the flexible template shown in  FIG. 8 , in accordance with a third alternate embodiment of the present invention;  
         [0024]      FIG. 16  is a flow diagram showing an exemplary imprinting operation employing the template shown in  FIG. 12 , in accordance with the present invention;  
         [0025]      FIG. 17  is a simplified plan view of a chucking system employed to retain the template shown in  FIG. 13 , with the template being disposed proximate to a substrate;  
         [0026]      FIG. 18  is a bottom up view of a chuck body shown in  FIG. 17 ;  
         [0027]      FIG. 19  is an exploded perspective view of components included in an imprint head, shown in  FIG. 1  in accordance with the present invention;  
         [0028]      FIG. 20  is a bottom perspective view of the components shown in  FIG. 19 ;  
         [0029]      FIG. 21  is a simplified plan view of the chucking system shown in  FIG. 17  with the template undergoing deformation to facilitate separation of the template from solidified imprinting material present on the substrate;  
         [0030]      FIG. 22  is a detailed view of region  217 , shown in  FIG. 21 , in accordance with an alternate embodiment;  
         [0031]      FIG. 23  is a simple plan view of template  214  shown in  FIG. 21 ;  
         [0032]      FIG. 24  is a detailed cross-section view showing the template of  FIG. 21  undergoing separation from formation  50 ; and  
         [0033]      FIG. 25  is a simplified cross-sectional view of the template shown in  FIG. 21 . 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0034]     Referring to  FIGS. 1 and 2 , a mold  36 , in accordance with the present invention, may be employed in system  10 , and may define a surface having a substantially smooth or planar profile (not shown). Alternatively, mold  36  may include features defined by a plurality of spaced-apart recessions  38  and protrusions  40 . The plurality of features defines an original pattern that is to be transferred into a substrate  42 . Substrate  42  may be comprised of a bare wafer or a wafer with one or more layers disposed thereon. To that end, reduced is a distance “d” between mold  36  and substrate  42 . In this manner, the features on mold  36  may be imprinted into an imprinting material, such as polymerizable material  24 , disposed on a portion of surface  44  that presents a substantially planar profile. It should be understood that substrate  42  may be a bare silicon wafer  48  or may include a native oxide or one or more layers, shown as primer layer  45 . In the present example, substrate  42  is discussed with respect to including a primer layer  45 . Exemplary compositions from which primer layer  45  and polymerizable material  42  may be formed are discussed in U.S. patent application Ser. No. 11/187,406, filed Jul. 22, 2005, entitled COMPOSITION FOR ADHERING MATERIALS TOGETHER, having Frank Xu listed as the inventor, assigned to the assignee of the present invention and is incorporated by reference herein.  
         [0035]     Referring to both  FIGS. 2 and 3 , the imprinting material may be deposited using any known technique, e.g., spin-coating, dip coating and the like. In the present example, however, the imprinting material is deposited as a plurality of spaced-apart discrete droplets  46  on substrate  42 . Imprinting material is formed from a composition that may be selectively polymerized and cross-linked to record the original pattern therein, defining a recorded pattern.  
         [0036]     Specifically, the pattern recorded in the imprinting material is produced, in part, by interaction with mold  36 , e.g., electrical interaction, magnetic interaction, thermal interaction, mechanical interaction or the like. In the present example, mold  36  comes into mechanical contact with the imprinting material, spreading droplets  46 , so as to generate a contiguous layer of the imprinting material over surface  44  that is solidified into a formation  50 . Formation  50  includes projections  52  and recessed regions  34 . A height thickness t 1  of formation  50  is defined by projections  52 . Recessed region  54  defines a residual thickness t 2  of formation  50 . In one embodiment, distance “d” is reduced to allow imprinting material to ingress into and fill recessions  38 . To facilitate filling of recessions  38 , before contact between mold  36  and droplets  46 , the atmosphere between mold  36  and droplets  46  is saturated with helium or is completely evacuated or is a partially evacuated atmosphere of helium.  
         [0037]     Referring to  FIGS. 2, 3  and  4 , a problem addressed by the present invention concerns controlling the thickness of t 1  and t 2  after reaching a desired distance d. Specifically, exemplary dimensions of the features of mold  36 , e.g., width W 1  of protrusions  40  and width W 2  of recessions  38 , may be in the range of 30 to 100 nanometers. Height with thickness t 1  may be in a range of 400 nanometers to one micrometer ±20-80 nanometers. Residual thickness t 2  may be in a range of 400 nanometers to one micrometer ±20-80 nanometers. Thus, a height of projections  52 , measured from a nadir surface  55 , is in a range 40 to 140 nanometers. As a result, surface  44  presents a non-planar profile, e.g., undulations are present as hills  56  and troughs  57 . The undulations make problematic controlling thicknesses t 1  and t 2 .  
         [0038]     Referring to  FIGS. 3, 4  and  5 , undulations make difficult ensuring that thickness t 1  is substantially equal over the area of formation  150  and thickness t 2  is substantially equal over the area of formation  150 . For example, after solidifying imprinting material, formation  150  is formed in which regions over which thickness t 1  varies and thickness t 2  varies. For example, features in region  58  have a height thickness t′ 1 ±δt′ 1  and a residual thickness t′ 2 ±δt′ 2 , where δt′ 1  and δt′ 2  results from the variation in thickness t′ 1  and t′ 2 , respectively, due to the curvature of surface  44  in superimposition with region  58 . Similarly, features in region  60  have a height thickness t″ 1 ±δt″ 1  and a residual thickness t″ 2 ±δt″ 2 , where δt″ 1  and δt″ 2  correspond to the variation in thicknesses t″ 1  and t″ 2 , respectively, due to the curvature of surface  44  in superimposition with region  60 .  
         [0039]     Referring to  FIGS. 5, 6  and  7 , were the difference between residual thicknesses t′ 2 ±δt′ 2  and t″ 2 ±δt″ 2  greater than t′ 1 ±δt′ 1 , a distortion in the pattern formed in substrate  42  would occur. This can be seen after formation  150  has undergone a break-through etch to expose regions  62  and  64  and  66  of substrate  42 . Were it desired to commence etching of regions  62 ,  64  and  66 , the result would be recesses  68 ,  70  and  72 , with a largely unpatterned region  74  being present that results from no exposure of substrate  42  during the break-through etch. This is undesirable. Were it desired to pattern region  84  of substrate  42 , etching of formation  150  would occur until a break-through in region  60  occurs. This would cause substantially all of the features of region  58  to be removed. As a result, large regions of substrate  42  would remain unpatterned, due, inter alia, to the absence of masking material.  
         [0040]     Referring to  FIGS. 3, 4  and  8 , to reduce, if not abrogate, the problems presented by the undulations, template  114 , including a mold  136 , is made so as to conform to surface  44 . In this manner, mold  136  may conform in response to the presence of undulations, thereby minimizing variations among thickness t 1  and variations among thickness t 2  over the area of formation  50 . To that end, template  114  is fabricated from a relatively thin sheet of fused silica having a thickness  113 , measured from opposed sides  115  and  116 , up to approximately 1.5 millimeters, with of approximately 0.7 being preferred. With a thickness of 0.7 millimeter, flexibility is provided by establishing an area of template  114  to be approximately 4,225 square millimeters. The area of mold  136  may be any desired, e.g., from 625 square millimeters to be extensive with the area of substrate  42 .  
         [0041]     Referring to  FIGS. 8-12  the conformableness of template  114  affords mold  136  the functionality so that control of thicknesses t 1  and t 2  may be achieved in the face of undulations. Specifically, mold  136  contacts imprinting material so that formation  250  may be formed. Formation  250  has a first surface  252  that rests against substrate  42  and has a profile matching the profile of the surface  44  of substrate  42  in the presence of undulations. However, a difficulty presented by flexible mold  236  results from the generation of capillary forces between mold  136  and the polymerizable material in droplets  46 . Upon contact by mold  136  with a first sub-portion of the polymerizable material, e.g., droplets  46  in region  158 , capillary forces between mold  136  and the polymerizable material are generated. However, capillary forces are substantially absent in the remaining sub-section of the polymerizable material, e.g., droplets in regions  160  and  161 . To form formation  250 , fluid pressure is applied to side  115  to deform template  114  and, therefore, mold  136  so that the same contacts droplets  46  in regions  160  and  161 .  
         [0042]     As a result of the flexibility of mold  136 , control of thicknesses t 1  and t 2 , is achieved so that thickness t 1  is within a specified tolerance ±δt 1 , referred to as being substantially uniform. Similarly thickness t 2  is substantially uniform in that the same is within a specified tolerance ±δt 2 . The tolerance results from the distortion in the features that result from the mold  136  conforming to surface  44 . It was determined, however, that by maintaining δt 1  and δt 2  to be less than or equal to 5 nanometers over a 25 millimeter area that the distortions that result from the conformableness of mold  136  are acceptable. Specifically, after a break-through-etch of formation  250 , regions  162  over the entire area of substrate  42  are exposed. Thereafter, patterning of the entire surface of substrate may occur, shown as recessions  164 . In this manner, the entire substrate  42  may be patterned, thereby overcoming the problems associated with thickness t 1  having, as well as thickness t 2 , varying, over an area of substrate  42  to be patterned.  
         [0043]     Referring to both  FIGS. 8 and 13 , although template  114  is shown having a mold  136  with protrusions lying in a common plane P along with surface  116 , other templates may be employed. For example, template  214  may include a mesa  235  that embodies mold  236 . Typically, a height, h, of mesa  235  is approximately 15 micrometers, as measured from surface  216  to a top surface of a protrusion  240 .  
         [0044]     Referring to both  FIGS. 8 and 14 , in another embodiment, template  314  is substantially identical to template  114 , excepting that mold  336  is surrounded by an entrainment channel  337 . Entrainment channel  337  extends further from side  316  than recessions  338 . In yet another embodiment, template  414 , shown in  FIG. 15 , is substantially identical to template  114 , shown in  FIG. 8 , excepting that regions of side  416  lying outside of mold  436  are coplanar with recessions  438 .  
         [0045]     Referring to  FIGS. 4, 13  and  16 , during an exemplary operation, template  214  and substrate  42  are placed in proximity to one another, e.g., within one millimeter, at step  500 . At step  502 , template  214  is bowed so that side  216  facing substrate  42  and, therefore, mold  236 , both have a convex shape, defining a bowed template. Specifically, a neutral axis, N, of mold  236  is bowed so that a central portion moves 350-400 micrometers away from neutral axis N so as to have a curved shape. At step  504 , the relative distance between the bowed template and substrate  42  is reduced so that the bowed mold  236  is placed in contact with one or more of droplets  46  of imprinting material and subsequently conforms to the shape of the imprinting material disposed between mold  236  and substrate  42  under compression therebetween. Typically, mold  236  is centered with respect to substrate  42  before contacting the imprinting material. A central portion  233  of mold  236  is centered with respect to the area of substrate  42  that is to be patterned. In this example, nearly an entire surface  44  of substrate  44  is to be patterned. The dimension of the area of substrate  42  to be patterned is defined by the thicknesses of formation  250  and the aggregate volume of polymerizable material in droplets  46 . As a result, the area of mold  236  may be greater, less than or equal to the area of substrate  42 . Typically, central portion  233  of mold  236  contacts the center of the area (not shown) with the remaining portions of the imprinting area being subsequently contacted by the non-central portions of mold  236 .  
         [0046]     At step  506 , fluid pressure is applied to side  115  to attenuate, if not abrogate, variations among thickness t 1  of the area of formation  150  and variations among thickness t 2  over the area of formation  150 . Specifically, side  115  is subjected to a sufficient magnitude of fluid pressure to compress imprinting material between mold  236  and substrate  42  to the state whereby the imprinting material can no longer undergo compression. In this condition, the imprinting material demonstrates visco-elastic properties in that the same behaves as a solid. Further, in the visco-elastic state the imprinting material conforms fully with surface  44  so that a side of the imprinting material facing mold  236  has the same shape as surface  44 . Mold  236  is established to be more compliant than the imprinting material in a visco-elastic state and, therefore, fully conforms to the shape of the side of the imprinting material facing mold  236 . At step  508 , imprinting material is exposed to actinic radiation to solidify the same so as to conform to a shape of the mold  236  and surface  44  of substrate  42 . At step  510 , mold  236  is separated from the solidified imprinting material.  
         [0047]     Referring to  FIGS. 12, 17  and  18 , to facilitate control of the pressures on side  215  of template  214 , disposed opposite to mold  236 , a chuck body  520  is adapted to retain template  214  employing vacuum techniques. To that end, chuck body  520  includes first  522  and second  524  opposed sides. A side, or edge, surface  526  extends between first side  520  and second side  524 . First side  522  includes a first recess  532  and a second recess  534 , spaced-apart from first recess  532 , defining first  536  and second  538  spaced-apart support regions. First support region  536  cinctures second support region  538  and the first  532  and second  534  recesses. Second support region  538  cinctures second recess  534 . A portion  540  of chuck body  520  in superimposition with second recess  534  is transmissive to energy having a predetermined wavelength, such as the wavelength of actinic energy employed to solidify the polymerizable material mentioned above. To that end, portion  540  is made from a thin layer of material that is transmissive with respect to broad band ultraviolet energy, e.g., glass. However, the material from which portion  540  is made may depend upon the wavelength of energy produced by source  26 , shown in  FIG. 1 .  
         [0048]     Referring again to  FIGS. 17 and 18 , portion  540  extends from second side  524  and terminates proximate to second recess  534  and should define an area at least as large as an area of mold  236  so that mold  236  is in superimposition therewith. Formed in chuck body  520  are one or more throughways, shown as  542  and  544 . One of the throughways, such as throughway  542 , places first recess  532  in fluid communication with side surface  526 . The remaining throughways, such as throughway  542 , places second recess  532  in fluid communication with side surface  526 .  
         [0049]     It should be understood that throughway  542  may extend between second side  524  and first recess  532 , as well. Similarly, throughway  544  may extend between second side  524  and second recess  534 . What is desired is that throughways  542  and  544  facilitate placing recesses  532  and  534 , respectively, in fluid communication with a pressure control system, such a pump system  546 .  
         [0050]     Pump system  546  may include one or more pumps to control the pressure proximate to recesses  532  and  534 , independently of one another. Specifically, when mounted to chuck body  520 , template  136  rests against first  536  and second  538  support regions, covering first  532  and second  534  recesses. First recess  532  and a portion  548  of template  136  in superimposition therewith define a first chamber  550 . Second recess  534  and a portion  552  of template  136  in superimposition therewith define a second chamber  554 . Pump system  546  operates to control a pressure in first  550  and second  554  chambers. Specifically, the pressure is established in first chamber  550  to maintain the position of the template  214  with the chuck body  520  and reduce, if not avoid, separation of template  214  from chuck body  520  under force of gravity {right arrow over (g)}. The pressure in second chamber  554  may differ from the pressure in first chamber  548  to reduce, inter alia, distortions in the pattern generated by template  214  during imprinting, by modulating a shape of template  214 . For example, pump system  546  may apply a positive pressure in chamber  554  for the reasons discussed above. Pump system  546  is operated under control of processor  32 , shown in  FIG. 1 .  
         [0051]     Referring to  FIGS. 1, 17  and  19 , template  214  is coupled to imprint head  20  via coupling of chuck body  520  to a flexure  556  that is coupled to an orientation system  558 . Orientation system  558  moves template  214 . Flexure  556  is disclosed and claimed in U.S. patent application Ser. No. 11/142,838, filed Jun. 1, 2005, entitled “Compliant Device for Nano-Scale Manufacturing”, which is assigned to the assignee of the present invention, and is incorporated by reference herein. Orientation system  558  is disclosed in U.S. patent application Ser. No. 11/142,825, filed Jun. 1, 2005 entitled “Method and System to Control Movement of a Body for Nano-Scale Manufacturing,” which is assigned to the assignee of the present invention and incorporated by reference herein.  
         [0052]     Referring to both  FIGS. 19 and 20 , orientation system  558  is shown having an inner frame  560  disposed proximate to an outer frame  562 , and flexure ring  564 , discussed more fully below. Body  520  is coupled to orientation system  558  through flexure  556 . Specifically, body  520  is connected to flexure  556 , using any suitable means, such as threaded fasteners (not shown) located at the four corners of body  520  connecting to four corners of flexure  556  closest to the four corners of body  520 . Four corners  566  of flexure  556  that are closest to a surface  568  of inner frame  560  are connected thereto using any suitable means, such as threaded fasteners, not shown.  
         [0053]     Inner frame  560  has a central throughway  570 , and outer frame  562  has a central opening  572  in superimposition with central throughway  570 . Flexure ring  564  has an annular shape, e.g., circular or elliptical, and is coupled to inner frame  560  and outer frame  562  and lies outside of both central throughway  570  and central opening  572 . Specifically, flexure ring  564  is coupled to inner frame  560  at regions  574 ,  576  and  578 , and outer frame  562  at regions  580 ,  582  and  584  using any suitable means, such as threaded fasteners (not shown). Region  580  is disposed between regions  574  and  576  and disposed equidistant therefrom; region  582  is disposed between regions  576  and  58  and disposed equidistant therefrom; and region  584  is disposed between regions  574  and  58  and disposed equidistant therefrom. In this manner, flexure ring  564  surrounds flexure  556 , body  520 , and template  214  and fixedly attaches inner frame  560  to outer frame  562 .  
         [0054]     It should be understood that the components of orientation system  558  and flexure  556  may be formed from any suitable material, e.g., aluminum, stainless steel and the like. Additionally, flexure  556  may be coupled to orientation system  558  using any suitable means. In the present example, flexure  556  is coupled to surface  45  employing threaded fasteners (not shown) located at the four corners  586 .  
         [0055]     Referring to  FIGS. 17 and 19 , system  558  is configured to control movement of template  214  and to place the same in a desired spatial relationship with respect to a reference surface, such as substrate  42  disposed on stage  11 . To that end, a plurality of actuators  588 ,  590  and  592  are connected between outer frame  562  and inner frame  560  so as to be spaced about orientation system  558 . Each of actuators  588 ,  590  and  592  has a first end  594  and a second end  596 . First end  594  faces outer frame  562 , and second end  596  faces away from outer frame  562 .  
         [0056]     Referring to both  FIGS. 19 and 20 , actuators  588 ,  590  and  592  tilt inner frame  560  with respect to outer frame  562  by facilitating translational motion of inner frame  560  along three axes Z 1 , Z 2 , and Z 3 . Orientation system  558  may provide a range of motion of approximately ±1.2 mm about axes Z 1 , Z 2 , and Z 3 . In this fashion, actuators  588 ,  590  and  592  cause inner frame  560  to impart angular motion to both flexure  556  and, therefore, template  214  and body  520 , about one or more of a plurality of axes T 1 , T 2  and T 3 . Specifically, by decreasing a distance between inner frame  560  and outer frame  562  along axes Z 2  and Z 3  and increasing a distance therebetween along axis Z 1 , angular motion about tilt axis T 2  occurs in a first direction.  
         [0057]     Increasing the distance between inner frame  560  and outer frame  562  along axes Z 2  and Z 3  and decreasing the distance therebetween along axis Z 1 , angular motion about tilt axis T 2  occurs in a second direction opposite to the first direction. In a similar manner angular movement about axis T 1  may occur by varying the distance between inner frame  560  and outer frame  562  by movement of inner frame  560  along axes Z 1  and Z 2  in the same direction and magnitude while moving of the inner frame  560  along axis Z 3  in a direction opposite and twice to the movement along axes Z 1  and Z 2 . Similarly, angular movement about axis T 3  may occur by varying the distance between inner frame  560  and outer frame  562  by movement of inner frame  560  along axes Z 1  and Z 3  in the same direction and magnitude while moving of inner frame  560  along axis Z 2  in direction opposite and twice to the movement along axes Z 1  and Z 3 . Actuators  588 ,  590  and  592  may have a maximum operational force of ±200 N. Orientation System  558  may provide a range of motion of approximately ±0.15° about axes T 1 , T 2 , and T 3 .  
         [0058]     Actuators  588 ,  590  and  592  are selected to minimize mechanical parts and, therefore, minimize uneven mechanical compliance, as well as friction, which may cause particulates. Examples of actuators  588 ,  590  and  592  include voice coil actuators, piezo actuators, and linear actuators. An exemplary embodiment for actuators  588 ,  590  and  592  is available from BEI Technologies of Sylmar, Calif. under the trade name LA24-20-000A and are coupled to inner frame  560  using any suitable means, e.g., threaded fasteners. Additionally, actuators  588 ,  590  and  592  are coupled between inner frame  560  and outer frame  562  so as to be symmetrically disposed thereabout and lie outside of central throughway  570  and central opening  572 . With this configuration an unobstructed throughway between outer frame  562  to flexure  556  is configured. Additionally, the symmetrical arrangement minimizes dynamic vibration and uneven thermal drift, thereby providing fine-motion correction of inner frame  560 .  
         [0059]     The combination of the inner frame  560 , outer frame  562 , flexure ring  564  and actuators  588 ,  590  and  592  provides angular motion of flexure  556  and, therefore, body  520  and template  214  about tilt axes T 1 , T 2  and T 3 . It is desired, however, that translational motion be imparted to template  214  along axes that lie in a plane extending transversely, if not orthogonally, to axes Z 1 , Z 2 , and Z 3 . This is achieved by providing flexure  556  with the functionality to impart angular motion upon template  214  about one or more of a plurality of compliance axes, shown as C 1  and C 2 , which are spaced—part from tilt axes T 1 , T 2  and T 3  and exist on the surface of the template when the template, the template chuck, and the compliant device are assembled.  
         [0060]     Another embodiment of the present invention facilitates separation of mold  236  from the solidified imprinting material which forms, for example, formation  50 . This is based upon the finding that localizing initial separation to a relatively small area of the interface between mold  236  and the solidified imprinting material reduces the magnitude of upwardly forces imparted upon mold  236  by orientation system  558  necessary to achieve separation. A desirable result is that the probability of separation between substrate  42  and stage  11  is reduced.  
         [0061]     Referring to  FIG. 21 , a deleterious situation that the present invention seeks to avoid separation of substrate  42  from stage  11  upon separation of mold  236  from formation  50 . Imprint head  20  applies a sufficient force to overcome the forces of attraction between mold  236  and formation  50 . In the situation in which the area of mold  236  is substantially co-extensive with the area of substrate  42 , e.g., whole wafer imprinting, the force required to separate mold  236  from formation  50  is often much greater than the force of attraction between substrate  42  and stage  11 , e.g., a vacuum or electrostatic force of attraction between substrate  42  and stage  11 . Therefore, it is desirable to reduce the force applied to template  214  necessary to achieve separation of mold  236  from formation  50 . Specifically, it is desirable to ensure that the upwardly force required to separate template  114  from formation  50  is less than the downwardly applied by stage  11  to substrate  42  to maintain the same thereupon.  
         [0062]     The upwardly force required to separate template  214  from formation  50  is reduced by creating localized separation between mold  236  and formation  50  at a region proximate to a periphery of mold  236 . To that end, for mold  236  having an area substantially coextensive with substrate  42 , mold  236  will have a maximum area to ensure that a perimeter  237  thereof is spaced-apart from an edge  222  of substrate  42  approximately 1 millimeter, shown as distance R. Localized separation is obtained by initiating separation of mold  236  from the solidified imprinting material employing pump system  546  pressurizing chamber  554  to approximately 20 kPa. This distorts the shape of a region  217  of template  214  that surrounds mold  236 . A first portion  219  of the surface template  214  in region  217  is displaced downwardly away from a neutral position N P  toward substrate  42 , with the nadir of portion  219  being approximately 1 micrometer below surface  43  of substrate  42 . As a result, the distortion afforded to template  214  by pump system  546  should be sufficient to allow nadir portion  219  to extend from the neutral position N P  a magnitude that is greater than the thickness t 1 , shown in  FIG. 3 , and height h, shown in  FIG. 13 .  
         [0063]     Referring again to  FIGS. 21 and 22 , a second portion  220  of the surface of template  214  moves upwardly away from substrate  42 , with an apex thereof being spaced-apart from surface  43  approximately fifteen micrometers. A segment of template disposed between second portion  220  and nadir portion  219  contacts edge  222  of substrate  42 . The Young&#39;s modulus associated with template  214  results in a returning force F R  to facilitate returning region  217  to neutral position N P , wherein undulations shown as nadir portion  219  and second portion are attenuated to form arcuate surface  224 . The returning force F R  results from the material of template  214  undergoing movement to return to a reduced-stressed and/or reduced-strained state.  
         [0064]     Referring to both  FIGS. 21, 24  and  25 , the returning force F R  causes an area  221  of mold  236  proximate to region  217  to separate from substrate  42 , while segment  227  functions to press substrate  42  downwardly against stage  11 , firmly securing the same together. In this manner, separation mold  236  from formation  50  occurs by cantilevering template  214  with respect to substrate  42 . Specifically, portion  227  contacts edge  222  of substrate  42  holding the same against stage  11 , which reduces the upwardly force on template  214  required to separate mold  236  from substrate and prevents substrate  42  from separating from stage  11 . It can be said, therefore, that returning force F R  reduces the magnitude of the upwardly forces imparted upon mold  236  by orientation system  558  that are necessary to achieve separation. As a result, returning force F R  must be greater than the adhering force between area  221  and formation  50 . The returning force F R  results in an oblique angle θ being formed with respect to formation  50 , measured for example, between a plane P 2  in which nadir surfaces  138  of recessions  38  lie and a plane P 3  in which nadir surfaces  154  of recessed regions  54  lie. The back pressure and returning force F R  coupled with the angle θ, causes template  214  and, therefore, mold  236 , to have an arcuate shape in which region  221  is further from formation  50  than regions of mold  236  disposed remotely therefrom, center portions of mold  236  located proximate to center axis A. Typically, the angle θ will be on the order of micro-radians so that shearing of features in solidified layer  50  is on the order of pico-meters. The remaining portions of mold  236  are separated from formation  50  may be controlled by operation of actuators  588 ,  590  and  592 , shown in  FIG. 19 .  
         [0065]     Referring to both  FIGS. 19 and 25 , by having actuators  588 ,  590  and  592  move at approximately the same rate, mold  236  is separated from formation so that the last portions thereof proximate to region  221  are separated from formation  50  before regions proximate to center axis A. In this manner, regions of mold  236  that are radially symmetrically disposed about axis A are sequentially separated from formation  50 , e.g., region  221  separates then region  223 , then region  225  and etc. It should be understood, however, that regions  221 ,  223  and  225  are radially symmetrically disposed about axis A, due to the shape of mold  236 . It is entirely possible that mold  236  have a rectangular or square shape. As a result, the shape of regions sequentially removed from formation  50  would be complementary to the shape of perimeter  237 . As a result, regions of mold  236  that are concentric with respect to perimeter  237  are sequentially separated from formation  50 . It should be understood, however, that actuators  588 ,  590  and  592  may be operated so as to produce a peeling separation of mold  236  from formation  50 . This may be achieved by moving mold  236  about on of tilt axes T 1 , T 2  and T 3 .  
         [0066]     Referring to  FIGS. 21 and 22 , another manner to achieve localized separation of template  214  would include forming arcuate surface  224  of template that is proximate to mold  236 . Specifically, pump system  546  would create a pressure in pressurizing chamber  554  sufficient to bow arcuate surface  224  and provide the same with a substantially constant radius of curvature. The returning force F R  would induce localized separation between mold  236  and formation  50  proximate to region  221 , as discussed above. Thereafter, mold  236  may be separated from formation  50  employing the techniques discussed above. Forming contoured surface is particularly advantageous were mold  236  sized so as to be much smaller than the area of substrate  42 , e.g., were mold  236  to have an area of 625 square millimeters, cantilevering would not occur.  
         [0067]     The embodiments of the present invention described above are exemplary. Many changes and modifications may be made to the disclosure recited above, while remaining within the scope of the invention. The scope of the invention should not, therefore, be limited by the above description, but instead should be determined with reference to the appended claims along with their full scope of equivalents.