Abstract:
A pattern imprint template incudes a patterned recesses and a layer formed over the patterned recesses. The pattern recesses form a pattern in a resist when brought in contact with a substrate with a resist thereon. The layer formed over the patterned recesses has a first surface energy. The first surface energy is lower in comparison to a second surface energy of the substrate with the resist thereon. The lower first surface energy in comparison to the second surface energy of the substrate avoids trapping gas in the resist by pushing gas toward the imprint template for venting through the patterned recesses.

Description:
RELATED APPLICATIONS 
       [0001]    The instant application is a divisional application and claims the benefit and priority to the U.S. patent application Ser. No. 15/044,962 filed Feb. 16, 2016 and further claims the benefit and priority to the U.S. patent application Ser. No. 13/362,972 filed on Jan. 31, 2012, and are incorporated by reference in their entirety herein. 
     
    
     BACKGROUND 
       [0002]    Ultraviolet (UV) nano-imprint processes place an imprint template into a resist fluid deposited on a template substrate. The resist fluid fills the imprint template voids by capillary action. The flow of the fluid resist can trap gas in the imprint template void. The trapped gas creates bubbles in the UV cured resist creating void defects. 
       SUMMARY 
       [0003]    A pattern imprint template incudes a patterned recesses and a layer formed over the patterned recesses. The pattern recesses form a pattern in a resist when brought in contact with a substrate with a resist thereon. The layer formed over the patterned recesses has a first surface energy. The first surface energy is lower in comparison to a second surface energy of the substrate with the resist thereon. The lower first surface energy in comparison to the second surface energy of the substrate avoids trapping gas in the resist by pushing gas toward the imprint template for venting through the patterned recesses. These and other features and advantages will be apparent from a reading of the following detailed description. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0004]      FIG. 1  shows a block diagram of an overview of a method of surface tension control to reduce trapped gas bubbles of one embodiment. 
           [0005]      FIG. 2  shows a block diagram of an overview flow chart of a method of surface tension control to reduce trapped gas bubbles of one embodiment. 
           [0006]      FIG. 3A  shows for illustrative purposes only an example of surface tension interfacial flow rate effect of one embodiment. 
           [0007]      FIG. 3B  shows for illustrative purposes only an example of dominant imprint template water contact angles of one embodiment. 
           [0008]      FIG. 4A  shows for illustrative purposes only an example of a mechanism of bubble trapping of one embodiment. 
           [0009]      FIG. 4B  shows for illustrative purposes only an example of dominant imprint template surface tension of one embodiment. 
           [0010]      FIG. 4C  shows for illustrative purposes only an example of a trapped gas bubble of one embodiment. 
           [0011]      FIG. 4D  shows for illustrative purposes only an example of a substrate reduced hydrophobic surface of one embodiment. 
           [0012]      FIG. 4E  shows for illustrative purposes only an example of a suspended trapped gas bubble of one embodiment. 
           [0013]      FIG. 5A  shows for illustrative purposes only an example of a controlled increase of imprint template surface tension of one embodiment. 
           [0014]      FIG. 5B  shows for illustrative purposes only an example of a controlled dominance of substrate surface tension of one embodiment. 
           [0015]      FIG. 5C  shows for illustrative purposes only an example of a controlled pre-cured liquid resist wetting of one embodiment. 
           [0016]      FIG. 5D  shows for illustrative purposes only an example of a of a controlled liquid resist filling of template topography of one embodiment. 
           [0017]      FIG. 6A  shows for illustrative purposes only an example of surface tension modification process of one embodiment. 
           [0018]      FIG. 6B  shows for illustrative purposes only an example of modified surface tension chemistry liquid resist wetting of one embodiment. 
           [0019]      FIG. 7A  shows for illustrative purposes only an example of surface tension control imprint template design adjustments of one embodiment. 
           [0020]      FIG. 7B  shows for illustrative purposes only an example of surface tension modification imprint template undercut of one embodiment. 
           [0021]      FIG. 7C  shows for illustrative purposes only an example of an optimal surface tension control modification adjustment of one embodiment. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0022]    In a following description, reference is made to the accompanying drawings, which form a part hereof, and in which is shown by way of illustration a specific example in which the invention may be practiced. It is to be understood that other embodiments may be utilized and structural changes may be made without departing from the scope of the present invention. 
       General Overview: 
       [0023]    It should be noted that the descriptions that follow, for example, in terms of a method of surface tension control to reduce trapped gas bubbles is described for illustrative purposes and the underlying system can apply to any number and multiple types of surface tension control processes, stack fabrication processes and stack designs. In one embodiment the method of surface tension control to reduce trapped gas bubbles can be configured using a modification of surface chemistry. The modification of surface chemistry can be configured to include decreasing the surface tension of an imprint template and can be configured to include relatively increasing the surface tension of a substrate using the present invention. 
         [0024]      FIG. 1  shows a block diagram of an overview of a method of surface tension control to reduce trapped gas bubbles of one embodiment.  FIG. 1  shows a method of surface tension control which reduces or eliminates the formation of trapped gas bubbles in for example ultraviolet (UV) imprint processes. UV imprint processes are used in nano fabrication to transfer the topography of an imprint template to a substrate to for example create a master template or to fabricate stacks for example bit patterned media (BPM) of one embodiment. 
         [0025]    UV imprint processes place an imprint template onto liquid resist materials deposited on the surface of the substrate. The resist materials are cured using exposure of ultraviolet UV light through the imprint template. The UV exposure of the resist materials for example hardens the liquid resist thereby retaining the topography of the template of one embodiment. 
         [0026]    The liquid resist materials are deposited onto the surface of the substrate for example in droplets. The droplets flow between the surfaces of the imprint template and the substrate and merge. Capillary action fills the cavity or raised sections of the topography. The merging of the liquid resist droplets may trap gas in the resist. Trapped gas after curing becomes void defects of one embodiment. 
         [0027]    Voids (cured trapped gas bubbles) interfere with other processes such as reactive ion etch (RIE) used in the processes to transfer the template patterns. These interferences caused by the void defects can lead to missing pattern sections and deformities in the patterns. The missing pattern sections and deformities negatively affect the quality of a master template and any stacks fabricated made using the master template of one embodiment. 
         [0028]    The trapped gas bubbles are formed when merging of the liquid resist is uncontrolled. The flow rates of the liquid resist are governed by the surface tension due to the surface energy of the materials of the interface surfaces of the imprint template and substrate. The method of surface tension control to reduce trapped gas bubbles can alter gas bubble trapping mechanisms  100  of one embodiment. 
         [0029]    The alteration of the mechanism of bubble trapping is achieved by modification of surface chemistry  110 . The modification of surface chemistry  110  is performed to increase or decrease surface energy of imprint template or substrate  120  thereby controlling the levels of the surface tensions of both surfaces. The increase or decrease in the surface energy of imprint template or substrate  120  provides a method to control the interfacial flow rate of liquid resist materials  130  of one embodiment. 
         [0030]    The method to control the interfacial flow rate of liquid resist materials  130  can eliminate or reduce gas trapping  140 . The elimination or reduction of trapped gas bubbles prevents void defects from forming. The method of surface tension control to reduce trapped gas bubbles increases the quality of master templates and stacks such as bit patterned media (BPM) fabricated using UV imprint processes of one embodiment. 
       Detailed Description: 
       [0031]      FIG. 2  shows a block diagram of an overview flow chart of a method of surface tension control to reduce trapped gas bubbles of one embodiment.  FIG. 2  shows a method of surface tension control to alter gas bubble trapping mechanisms  100 . The method of surface tension control to reduce trapped gas bubbles alters the mechanisms of bubble trapping in for example UV imprint processes by the modification of surface chemistry  110 . 
         [0032]    The surface chemistry of the materials used in the fabrication of imprint templates and substrates determines the amount of surface energy. The surface energy can accelerate or inhibit flow rates of the liquid resist materials used in the UV imprint process pattern transfer. Materials such as quartz are used in the fabrication of the imprint template. Quartz, glass and silicon are examples of materials used in fabricating substrates used in nano fabrication to create master templates and for fabrication of stacks such as bit patterned media (BPM). A substrate may further include layers deposited on top of the substrate for example a chromium (Cr) or amorphous carbon (a-C) image layer of one embodiment. 
         [0033]    The flow of the liquid resist deposited on the surface of the substrate into the topography of the imprint template is the foundation of the UV imprint process to transfer patterns. The variety of materials used for both imprint templates and un-layered and layered substrates can cause uncontrolled flow rates to occur when the liquid resist materials are sandwiched between the two surfaces. Liquid resist is applied to the surface of the substrate in a deposition process for example dispensed by ink-jet nozzles in droplet form of one embodiment. 
         [0034]    Uncontrolled liquid resist flow rates can lead to gas being trapped between merging droplets beneath the imprint template. The trapped gas bubbles are transformed into void defects when the resist is cured with exposure to UV light. The bubble voids inside the cured (hardened) resist can for example cause non-uniformity of the etch rate in a RIE process. This can cause sections of the designed patterns to be deformed or be missing all together of one embodiment. 
         [0035]    The method of surface tension control to reduce trapped gas bubbles modification of surface chemistry  110  can increase or decrease surface energy of imprint template or substrate  120  surfaces that come into contact with the liquid resist. The modification of surface chemistry  110  can thusly control the interfacial flow rate of liquid resist materials  130 . The control of the flow rates of the interface opposing surfaces can eliminate or reduce gas trapping  140  and the void defects created by the trapped gas bubbles of one embodiment. 
         [0036]    The surface chemistry of an imprint template  200  can be modified for example using a deposition of extremely hydrophobic material  210 . The deposition of extremely hydrophobic material  210  includes for example fluoroalkylsilanes such as 1H, 1H, 2H, 2H-perfluorodecyltrichlorosilane (FDTS), 1H, 1H, 2H, 2H-perfluorooctyltriethoxysilane and 1H, 1H, 2H, 2H-perfluorooctyltrichlorosilane. The deposition of extremely hydrophobic material  210  can be performed using a vapor deposition process. The thickness of the vapor deposition can be controlled to not affect the imprint template pattern or the fabrication of the imprint template can be adjusted to adjust for the addition of the vapor deposit of one embodiment. 
         [0037]    The un-layered and layered substrate  220  can be modified for example using a deposition of adhesion promoters  230 . A substrate for example a quartz substrate has a hydrophilic surface on which liquid resist can flow easily. A deposit of adhesion promoters modifies the substrate to a hydrophobic surface to decrease the flow rate of a liquid resist. Adhesion promoters can include materials for example ValMat (Molecular Imprints) and mr-APS1 (Microresist Technology). The adhesion promoter materials can be deposited using processes for example a vapor deposition or a spun application to enhance adhesion force between the substrate  220  and cured resist of one embodiment. 
         [0038]    The increase or decrease surface energy of imprint template or substrate  120  surfaces can be applied to one or both interface surfaces. A liquid such as water is a relatively high surface energy material and flows at a fast rate when in contact with a higher energy surface (hydrophilic surface). Water when in contact with a material that has a lower surface energy (hydrophobic surface) may for example bead up due to a very low flow rate of one embodiment. 
         [0039]    When for example the liquid resist flow rate against the imprint template  200  interface surfaces is dominant or faster than the liquid resist flow rate against the substrate  220  interface surface it is easy to capture or trap gas bubbles and form void defects after the UV curing process. The modification of surface chemistry  110  in this example would decrease the surface energy of the imprint template  200  interface surfaces using for example a deposition of extremely hydrophobic material  210 . This modification of surface chemistry  110  then shifts the dominance in flow rates to the substrate  220  surfaces. The resulting increase in the wetting or flow rate of the liquid resist on the substrate  220  surfaces to be greater than that of the imprint template  200  results in fewer chances to trap gas in the inner part of resist layer of one embodiment. 
         [0040]    The modification of surface chemistry  110  creates a dominant substrate surface energy  240 . The UV imprint process continues with a liquid resist dispensed onto substrate surface  250 . An imprint template lowered into liquid resist  260  with the modified increased surface energy begins to control the interfacial flow rate of liquid resist materials  130 . The dominant substrate surface energy  240  produces controlled flow rates that eliminate or reduce gas trapping  140 . The method of surface tension control to reduce trapped gas bubbles thereby prevents formation of trapped gas bubbles that create void defects which negatively affect the quality of the UV imprint pattern transfer processes of one embodiment. 
       Surface Tension Interfacial Flow Rate Effect: 
       [0041]      FIG. 3A  shows for illustrative purposes only an example of surface tension interfacial flow rate effect of one embodiment.  FIG. 3A  shows a process in which an quartz imprint template  300  is placed on top of a pre-cured liquid resist  320  that has been deposited on top of a quartz substrate  310  for example in droplets. The clean environment used in the process may include a gas  330  such as helium. The quartz imprint template  300  can be fabricated using materials such as quartz or silicon. The quartz substrate  310  can be fabricated using materials such as quartz, glass or silicon as well. The exposed surface materials would be characterized by having equal surface energy  344  levels leading to equal surface tensions  340  when the quartz imprint template  300  and quartz substrate  310  are made of the same materials. This would cause the pre-cured liquid resist  320  to have an equal interfacial flow rate  348  along the two surfaces of one embodiment. 
         [0042]    The quartz substrate  310  can also be fabricated with multiple layers being deposited on top of the quartz substrate  310  surface such as an image layer using for example amorphous carbon (a-C) or Chromium (Cr). An adhesion layer can for example be deposited on top of the image layer to better adhere the resist materials to the substrate structure. Different materials carry various levels of surface energy. The effect of the different surface energy levels causes different surface tensions and the pre-cured liquid resist  320  to have different flow rates along the two unlike surfaces. Different pre-cured liquid resist  320  flow rates can cause the trapping of the gas  330  between merging droplets of the pre-cured liquid resist  320  of one embodiment. 
       Dominant Imprint Template Water Contact Angles: 
       [0043]      FIG. 3B  shows for illustrative purposes only an example of dominant imprint template water contact angles of one embodiment.  FIG. 3B  shows the quartz imprint template  300  and the opposing quartz substrate  310 . Between the opposing structures is gas  330  for example helium used in the clean fabrication environment. In one embodiment on top of the quartz substrate  310  is deposited an image layer  350  and a hydrophobic adhesion layer  352 . The hydrophobic adhesion layer  352  can be deposited to better adhere a pre-cured liquid resist  320  to the substrate structure. The pre-cured liquid resist  320  can for example be deposited on the surface of the substrate structure. After resist deposition the quartz imprint template  300  is lowered into the pre-cured liquid resist  320  causing the spreading or wetting of the liquid resist materials between the interfaces of the two opposing surfaces of one embodiment. 
         [0044]    The quartz imprint template  300  presents a hydrophilic surface contact for the pre-cured liquid resist  320 . The hydrophilic surface of the quartz forms an imprint template lower water contact angle  360  of for example 4° (degrees). The hydrophilic surface with the lower water contact angle has a higher surface energy  366  creating a higher surface tension  362  which leads to a faster interfacial flow rate  364  of the pre-cured liquid resist  320  of one embodiment. 
         [0045]    The hydrophobic adhesion layer  352  material deposited on the quartz substrate  310  modifies the surface to a hydrophobic surface contact for the pre-cured liquid resist  320 . The hydrophobic surface of the hydrophobic adhesion layer  352  material creates a substrate structure higher water contact angle  370  of for example 64° (degrees). The hydrophobic surface with the higher water contact angle has a lower surface energy  376  creating a lower surface tension  372  which leads to a slower interfacial flow rate  374  of the pre-cured liquid resist  320  of one embodiment. 
       Mechanism of Bubble Trapping: 
       [0046]      FIG. 4A  shows for illustrative purposes only an example of a mechanism of bubble trapping of one embodiment.  FIG. 4A  shows the quartz imprint template  300  and the quartz substrate  310  structure with the image layer  350  and the hydrophobic adhesion layer  352 . The pre-cured liquid resist  320  has been deposited in droplets on the hydrophobic adhesion layer  352  of the quartz substrate  310  structure and the quartz imprint template  300  lowered into the pre-cured liquid resist  320 . The gas  330  is seen between the two merging droplets of liquid resist of one embodiment. 
         [0047]    A dominant quartz imprint template surface tension  400  due to the nature of the different surface materials causes a faster interfacial flow rate  364  along the surface of the quartz imprint template  300 . A slower interfacial flow rate  374  of the pre-cured liquid resist  320  occurs along the surface of the hydrophobic adhesion layer  352  of one embodiment. 
       Dominant Imprint Template Surface Tension: 
       [0048]      FIG. 4B  shows for illustrative purposes only an example of dominant imprint template surface tension of one embodiment.  FIG. 4B  shows the quartz imprint template  300  and the quartz substrate  310  structure. The quartz substrate  310  structure can include the image layer  350  and hydrophobic adhesion layer  352 . The spreading of the pre-cured liquid resist  320  droplets increases as the quartz imprint template  300  is lowered  325  further into the pre-cured liquid resist  320 . A capillary filling action  410  is triggered as the pre-cured liquid resist  320  reaches the cavity area of the raised template topography. The dominant faster interfacial flow rate  364  along the imprint template lower surface tension  362  of  FIG. 3B  fills the cavity area of the raised template topography. The gas  330  below is cut off from venting along the raised template topography cavity. The slower interfacial flow rate  374  along the surface of the hydrophobic adhesion layer  352  leaves open the void filled with the gas  330  of one embodiment. 
       Trapped as Bubble: 
       [0049]      FIG. 4C  shows for illustrative purposes only an example of a trapped gas bubble of one embodiment.  FIG. 4C  shows the quartz imprint template  300  lowered  325  further into the pre-cured liquid resist  320  towards the quartz substrate  310 , image layer  350  and surface of the hydrophobic adhesion layer  352 . The capillary filling action  410  of  FIG. 4B  filling the cavity area of the raised template topography has prevented the venting of the gas  330  of  FIG. 3A . This creates a trapped gas bubble  430  that may be in contact with the hydrophobic adhesion layer  352  surface of one embodiment. 
       Substrate Reduced Hydrophobic Surface: 
       [0050]      FIG. 4D  shows for illustrative purposes only an example of a substrate reduced hydrophobic surface of one embodiment.  FIG. 4D  shows the quartz imprint template  300  lowered  325  further into the pre-cured liquid resist  320 . The faster interfacial flow rate  364  occurs along the surface of the quartz imprint template  300  as the pre-cured liquid resist  320  droplets merge closer together. The capillary filling action  410  fills the cavity of the imprint template topography of one embodiment. 
         [0051]    In one embodiment an adhesion layer  420  has been deposited on top of the image layer  350  on the quartz substrate  310 . The adhesion layer  420  is less hydrophobic than the hydrophobic adhesion layer  352  of  FIG. 3B  creating an increased substrate surface tension  424 . The increased substrate surface tension  424  causes an increased interfacial flow rate  428  of the pre-cured liquid resist  320  along the surface of the adhesion layer  420 . The increased interfacial flow rate  428  begins to close the merging droplets underneath the gas  330  of one embodiment. 
       Suspended Trapped as Bubble: 
       [0052]      FIG. 4E  shows for illustrative purposes only an example of a suspended trapped gas bubble of one embodiment.  FIG. 4E  shows the final positioning of the quartz imprint template  300  as it is lowered  325  further into the pre-cured liquid resist  320 . The adhesion layer  420  on top of the image layer  350  and quartz substrate  310  has completely closed the merged droplets of the pre-cured liquid resist  320  underneath the gas  330  of  FIG. 3A . The gas could not vent through the cavity of the template topography and has formed a suspended trapped gas bubble  440  of one embodiment. 
       Controlled Increase of Imprint Template Surface Tension: 
       [0053]      FIG. 5A  shows for illustrative purposes only an example of a controlled increase of imprint template surface tension of one embodiment.  FIG. 5A  shows the quartz imprint template  300  on to which an extremely hydrophobic material layer  500  has been deposited. The extremely hydrophobic material layer  500  can include for example materials such as fluoroalkylsilanes (FDTS) deposited for example by vapor or wet deposition. The extremely hydrophobic material layer  500  material presents an extremely hydrophobic surface interfacial contact for the pre-cured liquid resist  320  of one embodiment. 
         [0054]    The extremely hydrophobic material layer  500  creates an imprint template higher water contact angle  510  of for example 111° (degrees). The extremely hydrophobic surface with the higher water contact angle has a much lower surface energy  376  creating a much lower surface tension  372 . The lower surface tension  372  leads to a slower interfacial flow rate  374  of the pre-cured liquid resist  320  of one embodiment. 
         [0055]    The quartz substrate  310  has deposited on it the image layer  350  and the adhesion layer  420 . The hydrophobic surface of the adhesion layer  420  material forms a substrate water contact angle  520  of for example 64° (degrees) lower than the imprint template higher water contact angle  510 . The substrate lower water contact angle  520  in relationship to the imprint template higher water contact angle  510  creates a relatively higher surface energy  366  and accompanying relatively higher surface tension  362  on the surface of the adhesion layer  420 . The differential in surface tensions creates the relatively faster interfacial flow rate  364  of the pre-cured liquid resist  320  along the adhesion layer  420  surface. The controlled decrease of imprint template surface tension lessens the chances of trapping gas  330  and forming trapped gas bubbles in the pre-cured liquid resist  320  of one embodiment. 
       Controlled Dominance of Substrate Surface Tension: 
       [0056]      FIG. 5B  shows for illustrative purposes only an example of a controlled dominance of substrate surface tension of one embodiment.  FIG. 5B  shows a controlled dominance of substrate surface tension due to the controlled deposition of the extremely hydrophobic material layer  500  on the quartz imprint template  300 . The quartz substrate  310  structure with the image layer  350  and the adhesion layer  420  maintains its surface tension and accompanying flow rate. The extremely hydrophobic material layer  500  has a lower surface energy  376  and resulting lower surface tension  372  of one embodiment. 
         [0057]    The lower surface tension  372  produces a slower interfacial flow rate  374  of the pre-cured liquid resist  320  along the surface of the extremely hydrophobic material layer  500 . Relative to the decreased surface tension of the extremely hydrophobic material layer  500 , the adhesion layer  420  has the relatively higher surface energy  366  and higher surface tension  362  resulting in the faster interfacial flow rate  364 . The faster interfacial flow rate  364  of the pre-cured liquid resist  320  along the surface of the adhesion layer  420  forces the small gas  330  molecules (the kinetic diameter of He is 0.256 nm) to penetrate through the pores (about 0.3 nm diameter) of the quartz template. A dominant substrate surface tension  530  controls the flow rate of the pre-cured liquid resist  320  in a manner that prevents the trapping of gas of one embodiment. 
       Controlled Pre-Cured Liquid Resist Wetting: 
       [0058]      FIG. 5C  shows for illustrative purposes only an example of a controlled pre-cured liquid resist wetting of one embodiment.  FIG. 5C  shows the controlled pre-cured liquid resist wetting that occurs as the quartz imprint template  300  coated with the extremely hydrophobic material layer  500  is lowered  325  further into the pre-cured liquid resist  320 . The slower interfacial flow rate  374  along the surface of the extremely hydrophobic material layer  500  prevents the pre-cured liquid resist  320  from reaching the cavity of the raised template topography before the liquid resist fills from below of one embodiment. 
         [0059]    The faster interfacial flow rate  364  along the surface of the adhesion layer  420  merges the droplets of pre-cured liquid resist  320  above the quartz substrate  310  and image layer  350 . The filling of the interface from the bottom up forces the gas  330  towards the cavity for venting  540 . The capillary filling action  410  begins to fill the cavity as the pre-cured liquid resist  320  flowing from the bottom and along the surface of the extremely hydrophobic material layer  500  reach the cavity of one embodiment. 
       Controlled Liquid Resist Filling of Template Topography: 
       [0060]      FIG. 5D  shows for illustrative purposes only an example of a controlled liquid resist filling of template topography of one embodiment.  FIG. 5D  shows the quartz imprint template  300  and deposited extremely hydrophobic material layer  500  as they are lowered  325  further into the pre-cured liquid resist  320  to the final position. The layered quartz substrate  310  including the image layer  350  and the adhesion layer  420  has a continuous coating of the pre-cured liquid resist  320 . The surfaces of the extremely hydrophobic material layer  500  also have a continuous coating of the pre-cured liquid resist  320  of one embodiment. 
         [0061]    The dominant substrate surface tension  530  of  FIG. 5B  created with the method of surface tension control to reduce trapped gas bubbles has prevented any trapping of the gas  330  of  FIG. 3A . The controlled liquid resist filling of template topography prevents trapping gas bubbles and the formation of void defects in the cured resist materials and thereby increases the quality of stacks such as bit-patterned media (BPM) fabricated using a UV imprint process of one embodiment. 
       Surface Tension Modification Process: 
       [0062]      FIG. 6A  shows for illustrative purposes only an example of surface tension modification process of one embodiment.  FIG. 6A  shows one embodiment of the processes for the modification of surface chemistry  110  of  FIG. 1  in a UV imprint process. In this embodiment the process starts with a (bit-patterned media) BPM quartz imprint template  600 . Onto the BPM quartz imprint template  600  is a vapor deposition of fluoroalkylsilanes (FDTS)  610 . 
         [0063]    The extremely hydrophobic material layer  500  of  FIG. 5A  can include extremely hydrophobic materials such as fluoroalkylsilanes in compounds such as 1H, 1H, 2H, 2H-perfluorodecyltrichlorosilane (FDTS), 1H, 1H, 2H, 2H-perfluorooctyltriethoxysilane and 1H, 1H, 2H, 2H-perfluorooctyltrichlorosilane. The vapor or wet deposition of fluoroalkylsilanes (FDTS)  610  creates mono or multi-layers of fluoroalkylsilanes (FDTS) layer  615 . The fluoroalkylsilanes (FDTS) layer  615  creates a lower modified surface tension  625  on the FDTS coated quartz BPM imprint template  620  of one embodiment. 
         [0064]    The quartz substrate  310  is coated with an adhesion promoter layer  634 . The adhesion promoter layer  634  creates a higher modified surface tension  636  relative to the fluoroalkylsilanes (FDTS) layer  615 . An adhesion promoter layer coated substrate  630  can include an adhesion promoter such as ValMat (Molecular Imprints) and Mr-APS1 (Microresist Technology). An adhesion promoter layer coated substrate  630  may be used for example in a direct etch transfer of the cured resist pattern of one embodiment. 
         [0065]    The next step is to include for example pre-cured liquid resist dispensed by ink-jet nozzles in droplet form  640  on the adhesion promoter layer coated substrate  630 . The following step is to lower imprint template into liquid resist  650 . The FDTS coated quartz BPM imprint template  620  settles into the liquid resist beaded droplets  655  on the adhesion promoter layer coated substrate  630 . The processes continue on  FIG. 6B  of one embodiment. 
       Modified Surface Tension Chemistry Liquid Resist Wetting: 
       [0066]      FIG. 6B  shows for illustrative purposes only an example of modified surface tension chemistry liquid resist wetting of one embodiment.  FIG. 6B  shows the continuation of processes from one embodiment described in  FIG. 6A .  FIG. 6B  shows the pre-cured liquid resist  320  of  FIG. 3A  wetting results produced by the modification of surface chemistry  110  of  FIG. 1  during the UV imprint process of one embodiment. 
         [0067]    The lower imprint template into liquid resist  650  action produces imprint template contact forces wetting of liquid resist  660 . The lower surface tension of the modified FDTS coated quartz template  620  slows the spread of the liquid resist on these surfaces. The liquid resist initial interface wetting  662  has a much faster flow rate of spreading or wetting on the surfaces of an adhesion promoter layer coated substrate  630 . A dominant substrate surface tension meniscus  664  illustrates the more rapid wetting along the bottom surfaces of the interface of one embodiment. 
         [0068]    A modified surface chemistry controlled interfacial flow rate  670  promotes the capillary filling action  410 . The capillary filling action  410  of the cavities of the imprint template occurs from the bottom up as the action continues to lower imprint template into liquid resist  650 . The relative increased or accelerated flow rate created by the adhesion promoter layer coated substrate  630  causes the droplets to complete the lateral merging of the pre-cured liquid resist. The decrease or retardation of the flow rate caused by the FDTS coated quartz template  620  permits gas  330  venting  540  by penetrating through the pores of the quartz template of one embodiment. 
         [0069]    An imprint template lowered to final position  680  terminates the interfacing movements. The FDTS coated quartz template  620  and adhesion promoter layer coated substrate  630  surfaces and interface interior are fully wetted with liquid resist without trapped air bubbles  690 . The surface tension control achieves the full wetting of the pre-cured liquid resist without creating potential voids due to trapped gas bubbles. The UV imprint processes can continue beyond this step to cure the resist and transfer the BPM pattern into the substrate without void defects of one embodiment. 
       Surface Tension Control Imprint Template Design Adjustments: 
       [0070]      FIG. 7A  shows for illustrative purposes only an example of surface tension control imprint template design adjustments of one embodiment.  FIG. 7A  shows the imprint template  200  with for example the design cavity width  700  dimensions and the cavity height  710  dimensions. The deposition of the extremely hydrophobic material layer  500  used to modify the chemistry of the imprint template  200  surfaces adds an extremely hydrophobic material layer thickness  720 . The nano fabrication architecture deals for example in units of nanometers (nm). The vapor disposition of the addition of an extremely hydrophobic material may add a thickness ranging from a few nm to for example 100 nm of one embodiment. 
         [0071]    The materials selected for the imprint template  200 , extremely hydrophobic material layer  500 , substrate  220  of  FIG. 2 , adhesion layer  352  of  FIG. 3B  and pre-cured liquid resist  320  of  FIG. 3A  can vary. The thickness or volume of the materials may vary as well. For example the pre-cured liquid resist  320  of  FIG. 3A  may be dispensed in thicknesses of 110 nm, 70 nm, 50 nm, and 35 nm. The flow rate of pre-cured liquid resist  320  of  FIG. 3A  material with the same viscosity may be affected by the dispensed volume of one embodiment. 
         [0072]    The modification of the surface chemistry  110  of  FIG. 1  materials selected and the disposition thicknesses are adjusted to accommodate the variations. Therefore the surface tension control added thicknesses may distort the design dimensions of the imprint template  200 . Adjustments in the imprint template design dimensions made for the surface tension control added thicknesses achieve the original dimensions post depositions of one embodiment. 
       Surface Tension Modification Imprint Template Undercut: 
       [0073]      FIG. 7B  shows for illustrative purposes only an example of surface tension modification imprint template undercut of one embodiment.  FIG. 7B  shows an imprint template design undercut adjustment  750  being made to the imprint template  200  topography design dimensions. The topography is undercut by the extremely hydrophobic material layer thickness  720  dimension. An adjustment is made to for example the design cavity width  700  of  FIG. 7A  dimensions and the cavity height  710  of  FIG. 7A  dimensions using an imprint template undercut depth  740 . The adjustments in the imprint template design are then used in the etching of the imprint template topography when it is created of one embodiment. 
         [0074]      FIG. 7C  shows for illustrative purposes only an example of an optimal surface tension control modification adjustment of one embodiment.  FIG. 7C  shows an undercut adjusted imprint template  780  created using an optimal surface tension control modification adjustment  770 . The undercut adjusted imprint template  780  after the extremely hydrophobic material layer  500  is deposited maintains the same cavity width  700  dimensions and cavity height  710  dimensions of the original imprint template design. The original imprint template design dimensions can be achieved by adjusting for the extremely hydrophobic material layer thickness  720  of one embodiment. 
         [0075]    The optimal surface tension control modification adjustment  770  accommodates the control achieved using the modification of surface chemistry  110  of  FIG. 1  without changing the dimensions of the original imprint template design. The modifications to increase or decrease surface tension of imprint template or substrate  120  and faithful transfer of the imprint template pattern are achieved using the method of surface tension control to reduce trapped gas bubbles of one embodiment. 
         [0076]    The foregoing has described the principles, embodiments and modes of operation. However, the invention should not be construed as being limited to the particular embodiments discussed. The above described embodiments should be regarded as illustrative rather than restrictive, and it should be appreciated that variations may be made in those embodiments by workers skilled in the art without departing from the scope as defined by the following claims.