Mold for nanoimprinting, its production process, and processes for producing molded resin having fine concavo-convex structure on its surface and wire-grid polarizer

Abstract

To provide a mold for nanoimprinting capable of accurately transcribing a fine concavo-convex structure, available at a low cost and having high durability, its production process, and processes for producing a molded resin having a fine concavo-convex structure on its surface having the fine concavo-convex structure of the mold accurately transcribed, and a wire-grid polarizer, with high productivity. A mold 10 for nanoimprinting having on its mold surface a fine concavo-convex structure comprising a plurality of grooves 14 formed in parallel with one another at a constant pitch, which comprises a mold base 12 made of a resin having on its surface a fine concavo-convex structure to be the base of the fine concavo-convex structure, a metal oxide layer 16 covering the surface having the fine concavo-convex structure of the mold base 12 , and a release layer 18 covering the surface of the metal oxide layer 16 , is used.

1 . A mold for nanoimprinting having a fine concavo-convex structure on its mold surface, which comprises a mold base made of a resin having on its surface a fine concavo-convex structure to be the base of the fine concavo-convex structure, a metal oxide layer covering the surface having the fine concavo-convex structure of the mold base, and a release layer covering the surface of the metal oxide layer. 
     
     
         2 . The mold for nanoimprinting according to  claim 1 , wherein the fine concavo-convex structure on the mold surface is a structure having convex stripes or grooves. 
     
     
         3 . The mold for nanoimprinting according to  claim 2 , wherein the width of the convex stripes or the width of the grooves is from 10 nm to 50 μm on the average. 
     
     
         4 . The mold for nanoimprinting according to  claim 2 , wherein the thicknesses of the metal oxide layer and the release layer are at least 1 nm, respectively, and the total thickness of them is at most 0.4 time the width of the grooves. 
     
     
         5 . The mold for nanoimprinting according to  claim 1 , wherein the fine concavo-convex structure on the mold surface comprises a plurality of grooves formed in parallel with one another at a constant pitch, and the pitch of the grooves is from 30 to 300 nm. 
     
     
         6 . The mold for nanoimprinting according to  claim 1 , wherein the metal oxide layer is a layer containing an oxide of at least one metal selected from the group consisting of Si, Al and Zr. 
     
     
         7 . The mold for nanoimprinting according to  claim 1 , wherein the release layer is a release layer formed by a compound having a fluoroalkyl group (which may have an etheric oxygen atom). 
     
     
         8 . The mold for nanoimprinting according to  claim 1 , wherein the mold base is made of a cured product of a photocurable resin composition. 
     
     
         9 . A process for producing a mold for nanoimprinting, which comprises a step of forming a layer of a photocurable resin composition on the surface of a support substrate; a step of overlaying a master mold having a fine concavo-convex structure on its mold surface and the support substrate to sandwich the photocurable resin composition between the mold surface of the master mold and the surface of the support substrate; a step of curing the photocurable resin composition in a state where the photocurable resin composition is sandwiched to form a mold base having on its surface a fine concavo-convex structure reverse of the fine concavo-convex structure on the mold surface; a step of separating the mold base and the master mold; a step of forming a metal oxide layer on the surface having the concavo-convex structure of the mold base; and a step of forming a release layer on the surface of the metal oxide layer. 
     
     
         10 . The process for producing a mold for nanoimprinting according to  claim 9 , wherein the method of forming the metal oxide layer is a sputtering method. 
     
     
         11 . The process for producing a mold for nanoimprinting according to  claim 9 , wherein the method of forming the release layer is a method of bringing a solution containing a release agent into contact with the surface of the metal oxide layer, and then cleaning the surface of the metal oxide layer with a cleaning liquid, followed by drying. 
     
     
         12 . A process for producing a molded resin having a fine concavo-convex structure on its surface, which comprises a step of forming a layer of a photocurable resin composition on the surface of a support substrate; a step of overlaying the mold for nanoimprinting as defined in  claim 1  and the support substrate to sandwich the photocurable resin composition between the mold surface having the fine concavo-convex structure and the surface of the support substrate; a step of curing the photocurable resin composition in a state where the photocurable resin composition is sandwiched to form a molded resin having on its surface a fine concavo-convex structure reverse of the fine concavo-convex structure on the mold surface; and a step of separating the molded resin and the mold. 
     
     
         13 . A process for producing a wire-grid polarizer, which comprises a step of forming a layer of a photocurable resin composition on the surface of a support substrate; a step of overlaying the mold for nanoimprinting as defined in  claim 5  and the support substrate to sandwich the photocurable resin composition between the mold surface having the grooves and the surface of the support substrate; a step of curing the photocurable resin composition in a state where the photocurable resin composition is sandwiched to form a light-transmitting substrate having a plurality of convex stripes corresponding to the grooves on the mold surface; a step of separating the light-transmitting substrate and the mold; and a step of forming a metal layer on the convex stripes of the light-transmitting substrate.