Abstract:
A micro-casted silicon carbide nano-imprinting stamp and method of making a micro-casted silicon carbide nano-imprinting stamp are disclosed. A micro-casting technique is used to form a foundation layer and a plurality of nano-sized features connected with the foundation layer. The foundation layer and the nano-sized features are unitary whole that is made entirely from a material comprising silicon carbide (SiC) which is harder than silicon (Si) alone. As a result, the micro-casted silicon carbide nano-imprinting stamp has a longer service lifetime because it can endure several imprinting cycles without wearing out or breaking. The longer service lifetime makes the micro-casted silicon carbide nano-imprinting stamp economically feasible to manufacture as the manufacturing cost can be recouped over the service lifetime.

Description:
FIELD OF THE INVENTION  
         [0001]    The present invention relates generally to a structure and a method of forming a hardened nano-imprinting stamp from silicon carbide. More specifically, the present invention relates to a structure and a method of forming a hardened nano-imprinting stamp using a micro-casting process.  
         BACKGROUND OF THE ART  
         [0002]    Nano-imprinting lithography is a promising technique for obtaining nano-size (as small as a few tens of nanometers) patterns. A key step in forming the nano-size patterns is to first form an imprinting stamp that includes a pattern that complements the nano-sized patterns that are to be imprinted by the stamp.  
           [0003]    In FIG. 1 a , a prior nano-imprint lithography process includes an imprinting stamp  200  having a plurality of imprint patterns  202  formed thereon. In FIG. 1 b , the imprint patterns  202  consists of a simple line and space pattern having a plurality of lines  204  separate by a plurality of spaces  206  between adjacent lines  204 . The imprint patterns  202  are carried by a substrate  211 . By pressing (see dashed arrow  201 ) the imprinting stamp  200  into a specially designed mask layer  203 , a thickness of the mask layer  203  is modulated with respect to the imprint patterns  202  (see FIG. 1 a ) such that the imprint patterns  202  are replicated in the mask layer  203 .  
           [0004]    Typically, the mask layer  203  is made from a material such as a polymer. For instance, a photoresist material can be used for the mask layer  203 . The mask layer  203  is deposited on a supporting substrate  205 . Using a step and repeat process, the imprinting stamp  200  is pressed repeatedly onto the mask layer  203  to replicate the imprint patterns  202  in the mask layer  203  and to cover the whole area of the mask layer  203 . In FIG. 2, after the step and repeat process, the mask layer  203  includes a plurality of nano-size impressions  207  that complement the shape of the imprint patterns  202 . Next, in FIG. 3, the mask layer  203  is anisotropically etched (i.e. a highly directional etch) to form nano-sized patterns  209  in the mask layer  203 . Typically, the supporting substrate  205  or another layer (not shown) positioned between the mask layer  203  and the supporting substrate  205  serves as an etch stop for the anisotropic etch.  
           [0005]    In FIG. 4, each line  204  includes opposed side surfaces  204   s , a top surface  204   t , opposed face surfaces  204   f , and edges  204   e . A space  206  separates each line  204 . Typically, the imprint stamp  200  is made from a material such as silicon (Si). For example, the substrate  211  can be a silicon wafer and the line and space features ( 204 ,  206 ) can be made from silicon (Si) or polysilicon (α-Si). Silicon is the material of choice for nano-imprint stamps because there are well established microelectronics processes for manufacturing silicon based structures and circuits, and because silicon is readily available at a reasonable cost.  
           [0006]    However, one of the disadvantages of the prior imprint stamp  200  is that silicon is a soft material and is subject to breakage, damage, and wear from repeated pressing steps into the mask layer  203 . In FIG. 4, a section E-E of the line feature  204  is particularly subject to wear, damage, and breakage due to repeated pressing steps. In FIG. 5, an enlarged view of the section E-E of FIG. 4 illustrates that the edges  204   e , the top surface  204   t , the side surfaces  204   s , and the face surfaces  204   f  are particularly susceptible to wear W from only a few pressing with the mask layer  203 .  
           [0007]    In FIG. 6, the imprint stamp  200  is pressed  201  into the mask layer  203  so that the line features  204  are disposed in the mask layer  203 . Repeated pressing steps cause wear, damage, and breakage denoted as W at the edges  204   e  and the top surface  204   t  of the line features  204 . Only ten or fewer pressing steps can result in the imprint stamp  200  wearing to the point where it can no longer be used to form consistent, repeatable, and accurate imprint patterns  209 . In FIGS. 7 a  and  7   b , a more detailed view of the wear to the line features  204  shows that the wear is most severe along the edges  204   e  and top surface  204   t  as those portions of the line features  204  contact the mask layer  203  first and have surface features that are substantially normal to the direction of pressing  201 . Accordingly, as illustrated in FIGS. 8 a  and  8   b , the line feature  204  quickly deteriorates from the ideal line feature  204  of FIG. 8 a  to the worn out line features  204  of FIG. Bb after only a few pressing cycles with the mask layer  203 .  
           [0008]    Fabrication of the imprint stamp  200  is one of the most crucial and most expensive steps in the entire imprinting lithography process. Another disadvantage of the prior imprint stamp  200  is that a cost of manufacturing the imprint stamp  200  is not recouped because the imprint stamp  200  is damaged and/or wears out before an adequate number of pressing steps required to justify the manufacturing cost of the imprint stamp  200  can occur. Accordingly, the prior imprint stamp  200  is not economical to manufacture.  
           [0009]    Consequently, there exists a need for a nano-size imprinting stamp that is resistant to wear, damage, and breakage. There is also an unmet need for a nano-size imprinting stamp that can retain consistent, repeatable, and accurate imprint patterns over multiple pressing steps so that the cost of manufacturing the nano-size imprinting stamp is recovered.  
         SUMMARY OF THE INVENTION  
         [0010]    The micro-casted silicon carbide nano-imprinting stamp of the present invention solves the aforementioned disadvantages and limitations of the prior nano-imprinting stamps. The micro-casted silicon carbide nano-imprinting stamp of the present invention is stronger and tougher because silicon carbide is used as the material for the imprint stamp as opposed to the silicon material of the prior nano-imprinting stamps. The micro-casted silicon carbide nano-imprinting stamp of the present invention has an increased service lifetime; therefore, the cost of manufacturing the micro-casted silicon carbide nano-imprinting stamp can be recovered because the stamp can withstand many pressing cycles without wearing out, breaking, or being damaged, unlike the prior nano-imprinting stamps that are made from silicon.  
           [0011]    Other aspects and advantages of the present invention will become apparent from the following detailed description, taken in conjunction with the accompanying drawings, illustrating by way of example the principles of the present invention. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0012]    [0012]FIGS. 1 a  and  1   b  are profile and top plan views respectively of a prior imprint stamp and prior imprint patterns.  
         [0013]    [0013]FIG. 2 is a profile view of a prior mask layer with nano-size impression formed therein by the prior imprint stamp of FIG. 1 a.    
         [0014]    [0014]FIG. 3 is a profile view of the prior mask layer of FIG. 2 after an anisotropic etch step.  
         [0015]    [0015]FIG. 4 is a side profile view of a prior imprint stamp being pressed into a mask layer.  
         [0016]    [0016]FIG. 5 is a more detailed view depicting portions of a prior imprint stamp that are most susceptible to wear, breakage, or damage.  
         [0017]    [0017]FIG. 6 is a cross-sectional view depicting a prior imprint stamp pressed into a mask layer.  
         [0018]    [0018]FIGS. 7 a  and  7   b  depict wear to the prior imprint stamp resulting from the pressing step of FIG. 6.  
         [0019]    [0019]FIGS. 8 a  and  8   b  depict the rapid progression of wear to the prior imprint stamp after only a few pressing cycles.  
         [0020]    [0020]FIG. 9 is a profile view of a of a micro-casted silicon carbide nano-imprinting stamp including a plurality of nano-sized silicon carbide features according to the present invention.  
         [0021]    [0021]FIG. 10 is a profile view of a silicon carbide foundation layer and a plurality of nano-sized silicon carbide features according to the present invention.  
         [0022]    [0022]FIGS. 11 a  and  11   b  are cross-sectional views that depict an imprinting process using a micro-casted silicon carbide nano-imprinting stamp according to the present invention.  
         [0023]    [0023]FIGS. 12 a  through  12   c  are cross-sectional views that depict a method of forming a micro-casting mold according to the present invention.  
         [0024]    [0024]FIG. 13 is a top profile view of a plurality of nano-sized mold cavities according to the present invention.  
         [0025]    [0025]FIGS. 14 a  and  14   b  are cross-sectional views that depict a method of micro-casting a silicon carbide nano-imprinting stamp according to the present invention.  
         [0026]    [0026]FIGS. 15 through 18 are cross-sectional views that depict a method of extracting a micro-casted silicon carbide nano-imprinting stamp according to the present invention.  
         [0027]    [0027]FIGS. 19 a  through  22  are cross-sectional views that depict an alternative method of forming a micro-casted silicon carbide nano-imprinting stamp according to the present invention.  
         [0028]    [0028]FIGS. 23 a  through  25   b  are cross-sectional views that depict yet another method of forming a micro-casted silicon carbide nano-imprinting stamp according to the present invention. 
     
    
     DETAILED DESCRIPTION  
       [0029]    In the following detailed description and in the several figures of the drawings, like elements are identified with like reference numerals.  
         [0030]    As shown in the drawings for purpose of illustration, the present invention is embodied in a micro-casted silicon carbide nano-imprinting stamp and a method of micro-casting a silicon carbide nano-imprinting stamp. The micro-casted silicon carbide nano-imprinting stamp includes a handling substrate, a glue layer connected with the handling substrate, and a foundation layer connected with the glue layer and including a base surface and a plurality of nano-sized features that are connected with the foundation layer and extend outward of the base surface. Each nano-sized feature includes an outer surface that defines an imprint profile. The foundation layer and the nano-sized features are made entirely of a material comprising silicon carbide and the foundation layer and the nano-sized features are a micro-casted unitary whole, that is, they are formed as a single piece or unit.  
         [0031]    The micro-casted silicon carbide nano-imprinting stamp of the present invention is cost effective because the micro-casted silicon carbide nano-sized features are durable, resilient, and are harder than the silicon nano-sized features of prior nano-imprinting stamps. Therefore, the micro-casted silicon carbide nano-imprinting stamp has a longer service life that allows for the cost of manufacturing the micro-casted silicon carbide nano-imprinting stamp to be recovered before its useful service life has ended.  
         [0032]    Additionally, the micro-casted silicon carbide nano-imprinting stamp of the present invention is more accurate than the prior silicon nano-imprinting stamps because the silicon carbide (SiC) nano-sized features are a harder material than is silicon (Si) alone and therefore maintain their imprint profile over repeated pressing steps thereby producing repeatable, consistent, and dimensionally accurate imprints in a media imprinted by the micro-casted silicon carbide nano-imprinting stamp.  
         [0033]    In FIG. 9, a micro-casted silicon carbide nano-imprinting stamp  10  includes a handling substrate  15 , a glue layer  17  that is connected with the handling-substrate  15 , and a foundation layer  11  that is connected with the glue layer  17 . The foundation layer  11  includes a base surface  13  and a plurality of nano-sized features  12  that are connected with the foundation layer  11  and extending outward of the base surface  13 . The nano-sized features  12  include an outer surface that defines an imprint profile. The imprint profile can be the same or it can vary among the nano-sized features  12 . For instance, the imprint profile can be determined by the dimensions of the nano-sized features  12  such as their respective width W, length L, and height H. Although the nano-sized features  12  are illustrated as having a rectangular imprint profile, the present invention is not to be construed as being limited to the imprint profiles illustrated herein and the imprint profiles need not be rectangular.  
         [0034]    In FIGS. 9 and 10, together with the base surface  13 , the nano-sized features  12  define an imprint pattern that is to be transferred into a media (not shown) to be imprinted by the micro-casted silicon carbide nano-imprinting stamp  10 . For example, a space S between the nano-sized features  12  can be a part of the imprint pattern such that the nano-sized features  12  and the space S define a line and space pattern that is to be imprinted in the media.  
         [0035]    In FIG. 10, for a rectangular or square imprint profile, the outer surface of the nano-sized features  12  includes opposed side surfaces  12   s , a top surface  12   t , a front surface  12   f  and back surface  12   b , and edges  12   e . The nano-sized features  12  may not include the aforementioned surfaces if the imprint profile has a shape other than a rectangular or square shape. The nano-sized features  12  and the foundation layer  11  are a unitary whole. That is, they are a single piece that is formed as a unit from a micro-casting process that will be described below. Both the nano-sized features  12  and the foundation layer  11  are made from a material comprising silicon carbide (SIC). Although the material for the nano-sized features  12  and the foundation layer  11  is primarily silicon carbide, the silicon carbide can include other materials or trace amounts of other materials. For instance, the silicon carbide can include nitrogen (N) atoms as a dopant material.  
         [0036]    The handling substrate  15  can be made from a variety of materials including but not limited to a bear silicon wafer, a polysilicon (α-Si) coated silicon wafer, a silicon oxide (Sio 2 ) coated silicon wafer, a silicon nitride (Si 3 N 4 ) coated silicon wafer. A silicon wafer is a good choice for the handling substrate  15  because equipment used in microelectronics processing is well suited to handling silicon wafers, silicon wafers are a readily available low cost material, and silicon wafers are an excellent substrate material for wafer bonding processes.  
         [0037]    Although a variety of materials can be used for the handling substrate  15 , the material selected should be a durable material because the handling substrate  15  must carry the foundation layer  11  and must be able to withstand many imprinting cycles without breaking or warping. Additionally, the handling substrate  15  must be capable of being handled by processing equipment without breaking or damaging the foundation layer  11 , the nano-sized features  12 , or the base surface  13 .  
         [0038]    The glue layer  17  can be a material including but not limited to tungsten (W), titanium (Ti), titanium nitride (TIN), cobalt (Co), platinum (Pt), gold (Au), a gold-tin alloy (AuSn), silver (Ag), and a silicide of those metals with the silicon of the handling substrate  15 . For example, the glue layer  17  can be a tungsten silicide (WSi 2 ). As will be described below, the glue layer  17  mechanically bonds the foundation layer  11  with the handling wafer  15 . When silicon is selected for the handling substrate  15 , one of the aforementioned metals can be selected so that at an interface between the glue layer  17  and the handling substrate  15 , a silicide bond is formed. Preferably, a wafer bonding process is used to form the bond between the handling substrate  15  and the foundation layer  11  with the glue layer  17  serving as the bonding material.  
         [0039]    The actual dimensions of the nano-sized features  12  and the space S between the nano-sized features  12  will be application dependent and can also depend on a lithography limit of a lithography system used for lithographically defining the nano-sized features  12  and the spaces S. However, the dimensions will be less than about 1.0 μm and are more typically of a nanometer scale (i.e. sub 100 nm) and are therefore about 100.0 nm or less.  
         [0040]    In FIG. 11 a , a media  50  to be imprinted by the micro-casted silicon carbide nano-imprinting stamp  10  includes a imprint media  53  carried by a substrate  51 . The micro-casted silicon carbide nano-imprinting stamp  10  is urged (see dashed arrow U) into contact with the imprint media  53 . For instance the micro-casted silicon carbide nano-imprinting stamp  10  and/or the media  50  can be pressed into contact with each other. The amount of pressure used will be application dependent and will also depend on the material for the imprint media  53 . For example, the imprint media  53  can be a polymer material, such as photoresist.  
         [0041]    In FIG. 11 b , the micro-casted silicon carbide nano-imprinting stamp  10  is depicted already pressed into contact with the imprint media  53 . The nano-size features  12  are subject to pressure and wear all along their respective outer surfaces and in particular along various contact points C p , such as the edges  12   e , the opposed side surfaces  12   s , the top surface  12   t , a front surface  12   f  and back surface  12   b , and the base surface  13 . During the imprinting process, pressures of about 300 psi to about 500 psi or more are common. Accordingly, the potential for ware, breakage, or damage to the nano-size features  12  is reduced by the harder silicon carbide material of the micro-casted silicon carbide nano-imprinting stamp  10  of the present invention and the nano-size features  12  are therefore more resistant to wear in general and especially along the aforementioned contact points C p .  
         [0042]    In FIGS. 12 a  through  18 , a method of micro-casting a silicon carbide nano-imprinting stamp  10  includes forming a release layer  23  on a surface  21   s  of a substrate  21 . The release layer  23  can be deposited using a process including but not limited to chemical vapor deposition (CVD), physical vapor deposition (PVD), and sputtering. The release layer  23  can have a thickness of about several μm or less. The substrate  21  can be a material including but not limited to silicon (Si), single crystal silicon, and a silicon wafer. The release layer  23  can be made from a material including but not limited to those set forth in Table 1 below:  
                     TABLE 1                       Materials for the release layer 23                                Tetraethylorthosilicate (TEOS)       A Boron (B) doped Tetraethylorthosilicate (BSG)       A Phosphorus (P) doped Tetraethylorthosilicate (PSG)       A Boron (B) and Phosphorus (P) doped Tetraethylorthosilicate (BPSG)       Heavily Doped Polysilicon (α-Si)       Silicon Nitride (Si 3 N 4 )                  
 
         [0043]    In FIG. 12 b , a mold layer  25  is formed on a surface  23   s  of the release layer  23 . The material for the mold layer  25  should be easy to deposit, easy to etch, and capable of being patterned as a nanometer scale feature. Preferably, the mold layer  25  is deposited over a substantially flat substrate or release layer ( 21 ,  23 ) with a uniform deposition rate over the substrate or release layer ( 21 ,  23 ) so that the mold layer  25  is smooth and substantially flat over its surface  25   s . The mold layer  25  can be deposited using a process including but not limited to CVD, PVD, and sputtering. Suitable materials for the mold layer  25  include but are not limited to the materials set forth in Table 2 below:  
                         TABLE 2                       Materials for the mold layer 25                                    Silicon Oxide (SiO 2 )           Silicon Nitride (Si 3 N 4 )           Polysilicon (α-Si)           Crystalline Silicon (Si)                      
 
         [0044]    In FIG. 12 c , the mold layer  25  is lithographically patterned with a mask  24  and then etched to form a plurality of nano-sized mold cavities  31  that extend all the way to the release layer  23 . The material for the release layer  23  can be selected so that the release layer  23  serves as an etch stop for the material used to etch the mold layer  25 .  
         [0045]    For example, an isotropic etch process, such as reactive ion etching (RIE), can be used to form the nano-sized mold cavities  31 . Reactive ion etching is particularly well suited to forming vertical side wall surfaces for the nano-sized mold cavities  31 , especially when a desired imprint profile for the nano-sized features  12  that will be formed in the nano-sized mold cavities  31  are to have a rectangular or square imprint profile.  
         [0046]    The patterning of the mold layer  25  can be accomplished using well known microelectronics photolithography processes. For instance, the mask  24  can be a patterned layer of photoresist material. In FIG. 13, the nano-sized mold cavities  31  extend from a top surface  25   s  of the mold layer to the surface  23   s  of the release layer  23 . The dimensions of the nano-sized mold cavities  31  can be the same or it can vary among the nano-sized mold cavities  31  as illustrated in FIG. 13. The actual dimensions of the nano-sized mold cavities  31  will be application dependent and as stated above for the nano-sized features  12 , dimensions of about 1.0 μm or more preferably about 100 nm or less will be typical of the nano-sized mold cavities  31  because the imprint profile of the nano-sized features  12  are determined by the nano-sized mold cavities  31  in which they will be micro-casted.  
         [0047]    In FIG. 14 a , the nano-sized mold cavities  31  are completely filled with a material comprising silicon carbide (SIC). The portion of the silicon carbide that fills the nano-sized mold cavities  31  forms a plurality of the nano-sized features  12 ; whereas, the remainder of the silicon carbide forms the foundation layer  11  which is connected with the nano-sized features  12 . In FIG. 14 b , the foundation layer  11  is planarized (see line F-F) to form a substantially planar surface  1  is. A process such as chemical mechanical planarization (CMP) can be used to planarize the foundation layer  11  and form the substantially planar surface along the line F-F.  
         [0048]    In FIG. 15, a glue layer  17  is formed on the planar surface  11   s  of the foundation layer  11 . The glue layer  17  can be deposited using a process including but not limited to CVD, PVD, and sputtering. Suitable materials for the glue layer  17  include but are not limited to the materials set forth in Table 3 below:  
                         TABLE 3                       Materials for the glue layer 17                                    Tungsten (W)           Titanium (Ti)           Titanium Nitride (TiN)           Cobalt (Co)           Platinum (Pt)           Gold (Au)           A Gold-Tin (AuSn) Alloy           Silver (Ag)           A Silicide with the Above Materials                      
 
         [0049]    In FIG. 16 a , a handling substrate  15  is bonded with the glue layer  17  by applying pressure P and heat h to the handling substrate  15  and the substrate layer  21 . The heat h and pressure P are continued until the glue layer  17  forms a mechanical bond between the foundation layer  11  and the handling substrate  15 . The amount of pressure P and heat h necessary to form the bond will be application dependent and will depend on the materials selected for the foundation layer  11 , the glue layer  17 , and the handling substrate  15 . For example, for a gold-tin (AuSn) alloy wafer bond, the pressure P is about 5,000 lbs over an entire surface of a 4-inch wafer (i.e. ˜64 psi) and the heat h applied is about 320° C. As another example, for an oxide-to-oxide wafer bond, the heat h applied is about 1100° C. and the pressure P is about 1 atm (i.e. no added pressure). Suitable materials for the handling substrate  15  are identical to those set forth above in reference to FIGS. 9 and 10.  
         [0050]    In FIG. 16 b , a backside  21   b  of the substrate layer  21  is lithographically patterned (e.g. through a mask  28 ) and then etched to form a plurality of through holes  22  that extend to the release layer  23 . For instance, a reactive ion etch can be used to form the through holes  22 . After the through holes  22  are formed, the substrate layer  21  is released by introducing an etch material into the through holes  22  so that the release layer is etched away thereby releasing the substrate layer  21 . A hydrogen fluoride (HF) solution or vapor can be used to etch away the release layer  23 . For instance, a hydrogen fluoride etchant will etch a silicon oxide (Sio 2 ) based release layer made from materials such as BSG, BPSG, PSG, and TEOS.  
         [0051]    In FIG. 17, the remainder of the mold layer  25  is etched away to remove the mold layer  25  from the nano-sized features  12  and the foundation layer  11 . A hydrogen fluoride (HF) solution or vapor can be used to etch away the mold layer  25 .  
         [0052]    In FIG. 18, after the mold layer  25  is removed, what remains is the micro-casted silicon carbide nano-imprinting stamp  10  of the present invention. The micro-casted silicon carbide nano-imprinting stamp  10  can be used repeatedly to imprint the nano-sized features  12  into an imprint media  53  as was described above in reference to FIGS. 11 a  and  11   b . As a result of the imprinting process, nanometer scale features are imprinted into the imprint media  53  by the nano-sized features  12 .  
         [0053]    In one embodiment of the present invention, as illustrated in FIGS. 19 a  through  22 , the aforementioned release layer  23  is dispensed with, and instead, the mold layer  25  is formed directly on the substrate layer  21  as illustrated in FIG. 19 a . The material for the mold layer  25  should be easy to deposit, easy to etch, and capable of being patterned as a nanometer scale feature. Preferably, the mold layer  25  is deposited over a substantially flat substrate  21  with a uniform deposition rate over the substrate  21  so that the mold layer  25  is smooth and substantially flat over its surface  25   s.    
         [0054]    In FIG. 19 b , the mold layer  25  is then patterned and etched as was described above to form a plurality of nano-sized mold cavities  31  that extend all the way to the substrate layer  21 . The substrate layer  21  can serves as an etch stop for the material used to etch the mold layer  25 . The materials for the substrate layer  21  can be the same materials as set forth above and the mold layer  25  can be made from the materials set forth above in reference to Table 2.  
         [0055]    In FIG. 20, the nano-sized mold cavities  31  extend to the substrate layer  21  and can have dimensions that are the same or that can vary among the nano-sized mold cavities  31  as was described above.  
         [0056]    In the same manner as was described above in reference to FIGS. 14 a  through  16 , a foundation layer  11  and a plurality of nano-sized features  12  made from a material comprising silicon carbide are formed on the mold layer  25 . The foundation layer  11  is planarized and then a glue layer  17  is formed on the planar surface  11   s  of the foundation layer  11 . Next, in FIG. 21, a handling substrate  15  is bonded to the glue layer  17  by applying heat h and pressure P until the handling substrate  15  is mechanically bonded with the glue layer  17 . The materials for the glue layer  17  can be the same as set forth above in reference to Table 3.  
         [0057]    In FIG. 22, the substrate layer  21  can be removed from the mold layer  25  by grinding a backside  21   b  of the substrate layer  21  until the substrate layer  21  is removed from the mold layer  25 . For example, a process such as CMP can be used to grind away the substrate layer  21 . Subsequently, the mold layer  25  can be selectively etched away to release the foundation layer  11 . A hydrogen fluoride (HF) solution or vapor can be used to etch away the mold layer  25 .  
         [0058]    Alternatively, the substrate layer  21  can be removed from the mold layer  25  by patterning and then etching the backside  21   b  of the substrate layer  21  to form a plurality of through holes  22  therein that extend to the mold layer  25  (see FIG. 16). Next, a selective etchant, such as HF, can be introduced into the through holes  22  to etch away the mold layer  25  and thereby releasing the substrate layer  21  and the nano-sized features  12  and the foundation layer  11  as well. In FIG. 18, after the mold layer  25  is removed, what remains is the micro-casted silicon carbide nano-imprinting stamp  10  of the present invention.  
         [0059]    In yet another embodiment of the present invention, as illustrated in FIGS. 23 a  through  25 , a mold layer  25  having a substantially planar surface  25   s  is patterned  24  (see FIG. 23 a ) and then etched to form a plurality of nano-sized mold cavities  31  therein (see FIG. 23 b ). The mold layer  25  can be made from the materials set forth above in reference to Table 2.  
         [0060]    In FIG. 23 c , a plurality of nano-sized features  12  and a foundation layer  11  are formed by filling the nano-sized mold cavities  31  with a material comprising silicon carbide as was describe above. The foundation layer  11  is then planarized (see dashed line F-F) to form a substantially planar surface  11   s  thereon (see FIG. 24). In FIG. 24, a glue layer  17  is formed on the substantially planar surface  11   s  as was described above. Next, in FIG. 25 a , a handling substrate  15  is bonded to the glue layer  17  by applying heat h and pressure P as was also described above. The mold layer  25  can be removed from the foundation layer  11  by selectively etching the mold layer  25  until it is released or dissolved from the foundation layer  11 . A selective etch process such as a dry or wet etch can be used to selectively etch the material of the mold layer  25 . Alternatively, in FIG. 25 b , a backside  25   b  of the mold layer  25  can be ground (e.g. using CMP) to reduce a thickness of the mold layer  25  such that only a thin layer of the mold layer  25  still covers the top surfaces  12   t  of the nano-sized features  12 . A selective etch process such as reactive ion etching (RIE) can be used to selectively remove the remainder of the mold layer  25  from the foundation layer  11  (see FIG. 18). The materials for the glue layer  17  can be the same as those set forth above in reference to Table 3; whereas, the material for the handling substrate  15  can be the same as set forth above.  
         [0061]    Although several embodiments of the present invention have been disclosed and illustrated, the invention is not limited to the specific forms or arrangements of parts so described and illustrated. The invention is only limited by the claims.