Fabrication of microkeratome blade with alignment features

Abstract

Various methods relating to one or more registration features ( 94 ) associated with a cutting blade ( 56 ) are disclosed. A masking layer ( 118 ) is formed on a wafer ( 130 ) and is patterned to define a plurality of mask apertures ( 122 a - c ). An anisotropic etch simultaneously forms a first cutting edge surface ( 72 ) and at least one registration surface ( 94 ) for the blade ( 56 ) via the mask apertures 122 a and 122 b , respectively. The anisotropic etch stops at the same crystallographic plane for both the first cutting edge surface ( 72 ) and the registration surface(s) ( 94 ). This may be used to accurately register a cutting edge ( 80 ) of the blade ( 56 ) relative to one or more structures that may be associated with the blade ( 56 ).

What is claimed is:  
     
         1 . A method for fabricating a blade from a substrate comprising a first surface, said method comprising the steps of: 
 forming a masking layer on said first surface of said substrate;    transferring a blade mask onto said masking layer; and    etching said substrate through first and second openings in said blade mask that each expose a predetermined portion of said first surface of said substrate and that defines a first cutting edge surface and a first registration feature, respectively, for a first blade.    
     
     
         2 . A method, as claimed in  claim 1 , further comprising the step of: 
 aligning said blade mask to a first crystallographic plane associated with said substrate before said transferring step.    
     
     
         3 . A method, as claimed in  claim 1 , wherein: 
 said transferring step comprises using a technique selected from the group consisting of photomasking, masking, photolithography, and microlithography.    
     
     
         4 . A method, as claimed in  claim 1 , wherein: 
 said etching step comprises an anisotropic etch of said substrate.    
     
     
         5 . A method, as claimed in  claim 1 , wherein: 
 said etching step is a chemical etch.    
     
     
         6 . A method, as claimed in  claim 1 , wherein: 
 said etching step comprises etching said substrate to the same crystallographic plane at each of first and second spaced locations to define said first cutting edge surface and said first registration feature, respectively.    
     
     
         7 . A method, as claimed in  claim 1 , wherein: 
 said etching step comprises simultaneously forming said first cutting edge surface and said first registration feature.    
     
     
         8 . A method, as claimed in  claim 1 , wherein, 
 said etching step comprises defining first and second planar and parallel surfaces at first and second locations, respectively, wherein said first cutting edge surface comprises said first planar surface, and wherein said first registration feature comprises said second planar surface.    
     
     
         9 . A method, as claimed in  claim 1 , wherein: 
 an intersection between said first cutting edge surface and a second surface of said substrate defines a first cutting edge, wherein said first and second surfaces of said substrate are oppositely disposed, and wherein said etching step comprises etching entirely through said substrate from only a first side of said substrate to define said first cutting edge.    
     
     
         10 . A method, as claimed in  claim 9 , wherein: 
 said etching step comprises etching entirely through said substrate from only said first side of said substrate to define said first registration feature.    
     
     
         11 . A method, as claimed in  claim 1 , wherein: 
 said etching step comprises etching entirely through said substrate from only one side of said substrate to define said first registration feature.    
     
     
         12 . A method, as claimed in  claim 1 , wherein: 
 said etching step comprises etching said substrate to define a first registration cavity, wherein said first registration cavity is defined in part by a first registration surface, wherein said first registration surface comprises said first registration feature, and wherein said first cutting edge surface and said first registration surface are disposed in parallel relation.    
     
     
         13 . A method, as claimed in  claim 12 , wherein: 
 said etching step comprises defining at least a portion of a perimeter of said first blade, wherein an entirety of said first registration cavity is disposed inwardly of said perimeter.    
     
     
         14 . A method, as claimed in  claim 12 , wherein: 
 said etching step comprises etching entirely through said substrate to define said first registration cavity.    
     
     
         15 . A method, as claimed in  claim 12 , wherein: 
 said first cutting edge surface extends between a first edge and a first cutting edge, wherein said first edge is defined by an intersection of said first cutting edge surface and said first surface of said substrate; and    said first registration surface extends between second and third edges, wherein said second edge is defined by an intersection between said first registration surface and said first surface of said substrate, and wherein said third edge and said first cutting edge are disposed within a common reference plane that is parallel with said first surface.    
     
     
         16 . A method, as claimed in  claim 15 , wherein: 
 said substrate comprises a second surface that is disposed opposite of said first surface, wherein said third edge is defined by an intersection between said first registration surface and said second surface of said substrate.    
     
     
         17 . A method, as claimed in  claim 1 , further comprising the steps of: 
 etching said substrate through a third opening in said blade mask that exposes a predetermined portion of said first surface of said substrate and that defines a second registration feature for said first blade.    
     
     
         18 . A method, as claimed in  claim 17 , wherein: 
 said etching step comprises etching said substrate to the same crystallographic plane at each of first, second, and third spaced locations to define said first cutting edge surface, said first registration feature, and said second registration feature, respectively.    
     
     
         19 . A method, as claimed in  claim 17 , wherein: 
 said etching step comprises simultaneously forming said first cutting edge surface, said first registration feature, and said second registration feature.    
     
     
         20 . A method, as claimed in  claim 17 , wherein, 
 said etching step comprises defining first, second, and third planar surfaces at first, second, and third locations, respectively, wherein said first cutting edge surface comprises said first planar surface, wherein said first registration feature comprises said second planar surface, wherein said second registration feature comprises said third planar surface, and wherein said first planar surface is parallel with each of said second and third planar surfaces.    
     
     
         21 . A method, as claimed in  claim 20 , wherein: 
 said second and third planar surfaces are disposed within a common reference plane.    
     
     
         22 . A method, as claimed in  claim 17 , wherein: 
 said etching step comprises etching said substrate to define first and second registration cavities, wherein said first and second registration cavities are defined in part by first and second registration surfaces, respectively, wherein said first and second registration surfaces comprise said first and second registration features, respectively, wherein said first cutting edge surface is disposed in parallel relation with each of said first and second registration surfaces, and wherein said first and second registration surfaces are disposed in spaced relation.    
     
     
         23 . A method, as claimed in  claim 22 , wherein: 
 said etching step comprises defining a perimeter of said first blade, wherein an entirety of each of said first and second registration cavities is disposed inwardly of said perimeter.    
     
     
         24 . A method, as claimed in  claim 22 , wherein: 
 said first and second registration surfaces are disposed within a common reference plane.    
     
     
         25 . A method for fabricating a blade from a substrate, said method comprising the steps of: 
 executing a first etching step comprising etching said substrate at a first location to define a first cutting edge surface of a first blade; and    executing a second etching step comprising etching said substrate at a second location to define a first registration cavity of said first blade, wherein said first location is spaced from said second location.    
     
     
         26 . A method, as claimed in  claim 25 , wherein: 
 said first and second etching steps are executed concurrently using the same etchant.    
     
     
         27 . A method, as claimed in  claim 26 , wherein: 
 said etchant is an anisotropic etchant.    
     
     
         28 . A method, as claimed in  claim 25 , wherein: 
 said first etching step terminates upon reaching a first plane, wherein said second etching step terminates upon reaching a second plane, and wherein said first and second planes are parallel.    
     
     
         29 . A method, as claimed in  claim 28 , wherein: 
 said first and second planes each correspond with a common crystallographic plane.    
     
     
         30 . A method, as claimed in  claim 25 , wherein: 
 said second etching step comprises defining a first registration surface that is parallel with said first cutting edge surface.    
     
     
         31 . A method, as claimed in  claim 25 , wherein: 
 said second etching step comprises etching entirely through said substrate.    
     
     
         32 . A method, as claimed in  claim 25 , wherein: 
 said first cutting edge surface extends between a first edge and a first cutting edge, wherein said first edge is defined by an intersection of said first cutting edge surface and a first surface of said substrate; and    said second etching step comprises defining a first registration surface that extends between second and third edges, wherein said second edge is defined by an intersection between said first registration surface and said first surface of said substrate, and wherein said third edge and said first cutting edge are disposed within a common reference plane that is parallel with said first surface.    
     
     
         33 . A method, as claimed in  claim 32 , wherein: 
 said substrate comprises a second surface disposed opposite of said first surface, wherein said third edge is defined by an intersection between said first registration surface and said second surface of said substrate.    
     
     
         34 . A method, as claimed in  claim 25 , further comprising the step of: 
 executing a third etching step comprising etching said substrate to define at least a portion of a perimeter of said first blade, wherein an entirety of said first registration cavity is disposed inwardly of said perimeter.    
     
     
         35 . A method, as claimed in  claim 25 , further comprising the steps of: 
 executing a third etching step comprising etching said substrate at a third location to define a second registration cavity of said first blade, wherein said third location is spaced from each of said first and second locations.    
     
     
         36 . A method, as claimed in  claim 35 , wherein: 
 said first, second, and third etching steps are executed concurrently using the same etchant.    
     
     
         37 . A method, as claimed in  claim 35 , wherein: 
 said first, second, and third etching steps comprise etching said substrate to the same crystallographic plane at each of said first, second, and third spaced locations to define said first cutting edge surface, said first registration cavity, and said second registration cavity, respectively.    
     
     
         38 . A method, as claimed in  claim 35 , wherein: 
 said first, second, and third etching steps comprise simultaneously forming said first cutting edge surface, said first registration cavity, and said second registration cavity, respectively.    
     
     
         39 . A method, as claimed in  claim 35 , wherein, 
 said first, second, and third etching steps comprise defining first, second, and third planar surfaces, respectively, wherein said first cutting edge surface comprises said first planar surface, wherein part of said first registration cavity is defined by said second planar surface, wherein part of said second registration cavity is defined by said third planar surface, and wherein said first planar surface is parallel with each of said second and third planar surfaces.    
     
     
         40 . A method, as claimed in  claim 39 , wherein: 
 said second and third planar surfaces are disposed within a common reference plane.    
     
     
         41 . A method, as claimed in  claim 35 , further comprising the step of: 
 executing a fourth etching step comprising etching said substrate to define at least a portion of a perimeter of said first blade, wherein an entirety of each of said first and second registration cavities is disposed inwardly of said perimeter.    
     
     
         42 . A method, as claimed in  claim 25 , further comprising the steps of: 
 forming a masking layer on a first surface of said substrate;    transferring a blade mask onto said masking layer; and    etching said substrate through first and second openings in said blade mask that each expose a predetermined portion of said first surface of said substrate and that defines said first cutting edge surface and said first registration cavity, respectively.    
     
     
         43 . A method, as claimed in  claim 42 , further comprising the step of: 
 aligning said blade mask to at least one crystallographic plane associated with said substrate before said transferring step.    
     
     
         44 . A method, as claimed in  claim 42 , wherein: 
 said transferring step comprises using a technique selected from the group consisting of photomasking, masking, photolithography, and microlithography.    
     
     
         45 . A method for fabricating a blade from a substrate, comprising the steps of: 
 creating at least one opening that extends completely through said substrate, wherein said creating step comprises defining at least a portion of a perimeter of a first blade; and    defining a first registration feature from said substrate that is associated with said first blade, wherein said defining a first registration feature step is executed during said creating step.    
     
     
         46 . A method for fabricating a blade from a substrate, comprising the steps of: 
 creating at least one opening that extends completely through said substrate, wherein said creating step comprises defining at least a portion of a perimeter of a first blade; and    defining a first registration feature from said substrate that is associated with said first blade, wherein said defining a first registration feature step comprises using a same technique as said creating step.