Mold, mold manufacturing method and method for manufacturing anti-reflection film using the mold

Abstract

A mold of at least one embodiment of the present invention includes: a base; a conductive layer provided on the base; and an anodized film provided on the conductive layer, the anodized film having an inverted motheye structure in its surface, the inverted motheye structure having a plurality of recessed portions whose two-dimensional size viewed in a direction normal to the surface is not less than 10 nm and less than 500 nm, wherein the base, the conductive layer, and the anodized film are capable of transmitting ultraviolet light.

1 . A mold, comprising:
 a base;   a conductive layer provided on the base; and   an anodized film provided on the conductive layer, the anodized film having an inverted motheye structure in its surface, the inverted motheye structure having a plurality of recessed portions whose two-dimensional size viewed in a direction normal to the surface is not less than 10 nm and less than 500 nm,   wherein the base, the conductive layer, and the anodized film are capable of transmitting ultraviolet light.   
     
     
         2 . The mold of  claim 1 , wherein the conductive layer is formed by a titanium film whose thickness is not more than 100 nm. 
     
     
         3 . The mold of  claim 1 , further comprising a mold release layer provided on the anodized film. 
     
     
         4 . The mold of  claim 1 , wherein the anodized film has minute pores on a side of the plurality of recessed portions which is closer to the conductive layer, the minute pores being smaller than the plurality of recessed portions. 
     
     
         5 . The mold of  claim 1 , wherein the anodized film includes a porous alumina layer which has the inverted motheye structure in its surface and an alumina layer which does not have a minute pore, the alumina layer being provided on a side of the porous alumina layer which is closer to the conductive layer. 
     
     
         6 . The mold of  claim 5 , wherein a thickness of the alumina layer which does not have a minute pore is not less than 100 nm. 
     
     
         7 . A method of fabricating a mold that has an inverted motheye structure in its surface, the inverted motheye structure having a plurality of recessed portions whose two-dimensional size viewed in a direction normal to the surface is not less than 10 nm and less than 500 nm, the method comprising the steps of:
 (a) providing a base which is capable of transmitting ultraviolet light;   (b) forming on the base a conductive layer which is capable of transmitting ultraviolet light;   (c) depositing an aluminum film on the conductive layer; and   (d) anodizing an entirety of the aluminum film, step (d) including
 (d1) anodizing the aluminum film to form a porous alumina layer which has a plurality of very small recessed portions, 
 (d2) after step (d1), bringing the porous alumina layer into contact with an etchant, thereby enlarging the plurality of very small recessed portions of the porous alumina layer, and 
 (d3) after step (d2), further anodizing the aluminum film to grow the plurality of very small recessed portions. 
   
     
     
         8 . The method of  claim 7 , wherein step (d) includes, after step (d3), further performing step (d2) and step (d3). 
     
     
         9 . The method of  claim 7 , wherein step (d) further includes
 (da) forming the inverted motheye structure in a surface of the porous alumina layer through steps (d1) to (d3), and   (db1) after step (da), further anodizing the aluminum film to form minute pores on a side of the porous alumina layer which is closer to the conductive layer, the minute pores being smaller than the plurality of recessed portions.   
     
     
         10 . The method of  claim 9 , further comprising
 (db2) after step (db1), anodizing the aluminum film to form an alumina layer which does not have the minute pores on a side of the porous alumina layer which is closer to the conductive layer.   
     
     
         11 . The method of  claim 10 , wherein the step (db2) is performed in an electrolytic solution whose pH is more than 4.0 and not more than 7.0. 
     
     
         12 . The method of  claim 11 , wherein the electrolytic solution used in step (db2) is an aqueous solution which contains at least one of acids or salts selected from a group consisting of tartaric acid, ammonium tartrate, potassium sodium tartrate, boric acid, ammonium borate, ammonium oxalate, ammonium citrate, maleic acid, malonic acid, phthalic acid, and citric acid. 
     
     
         13 . The method of  claim 10 , wherein step (db2) is performed in an acidic aqueous solution with a concentration of not more than 0.1 mol/L. 
     
     
         14 . A method of fabricating an antireflection film, comprising:
 providing the mold as set forth in  claim 1  and a work; and   irradiating a UV-curable resin provided between the mold and a surface of the work with ultraviolet light supplied through the mold, thereby curing the UV-curable resin.