Optical films and methods of making the same

Abstract

In general, in a first aspect, the invent features a method, including providing a layer having a plurality of spaced-apart lines of a first material extending along a first direction and forming a line of a second material on opposing surfaces of each line of the first material, the first and second materials being different and adjacent lines of the second material being discontinuous. After forming the lines of the second material, forming pairs of spaced-apart lines of a third material between adjacent pairs of the lines of the second material, wherein each line of the third material is spaced apart from the closest line of the second material and the first and third materials are different.

1 . A method, comprising:
 providing a layer comprising a plurality of spaced-apart lines of a first material extending along a first direction;   forming a line of a second material on opposing surfaces of each line of the first material, the first and second materials being different and adjacent lines of the second material being discontinuous;   after forming the lines of the second material, forming pairs of spaced-apart lines of a third material between adjacent pairs of the lines of the second material,   wherein each line of the third material is spaced apart from the closest line of the second material and the first and third materials are different.   
     
     
         2 . The method of  claim 1 , wherein the lines of the first material have a pitch of 200 nm or less. 
     
     
         3 . The method of  claim 1 , wherein forming the lines of the second material comprises:
 forming a continuous layer of the second material on the layer comprising the lines of the first material; and   removing portions of the continuous layer of the second material to provide the lines of the second material.   
     
     
         4 . The method of  claim 3 , wherein the continuous layer of the second material is formed using atomic layer deposition. 
     
     
         5 . The method of  claim 3 , wherein the continuous layer of the second material conforms to the surface profile of the layer comprising the plurality of lines of the first material. 
     
     
         6 . The method of  claim 3 , wherein removing the portions of the continuous layer of the second material comprises etching the layer of the second material. 
     
     
         7 . The method of  claim 1 , wherein the second material has a refractive index of 1.8 or more and an extinction coefficient of 1.8 or more for a wavelength λ that is 400 nm or less. 
     
     
         8 . The method of  claim 1 , wherein the lines of the second material have a line width of 20 nm or less. 
     
     
         9 . The method of  claim 1 , wherein the lines of the second material have a thickness of 100 nm or more. 
     
     
         10 . The method of  claim 1 , wherein the lines of the second material have an aspect ratio of 5:1 or more. 
     
     
         11 . The method of  claim 1 , wherein forming the lines of the third material comprises:
 forming a continuous layer of a fourth material over the lines of the second material; and   forming a layer of the third material over the layer of the fourth material,   wherein the second and third materials are different from the fourth material.   
     
     
         12 . The method of  claim 11 , wherein forming the lines of the third material further comprises removing portions of the continuous layer of the third material to provide the lines of the third material. 
     
     
         13 . The method of  claim 1 , wherein the third material is the same as the second material. 
     
     
         14 . The method of  claim 1 , wherein the second material has a refractive index of 1.8 or more and an extinction coefficient of 1.8 or more for a wavelength λ that is 400 nm or less. 
     
     
         15 . The method of  claim 1 , wherein the lines of the third material have a line width of 20 nm or less. 
     
     
         16 . The method of  claim 1 , wherein the lines of the third material have a thickness that is different from a thickness of the lines of the second material. 
     
     
         17 . The method of  claim 16 , wherein the thickness of the lines of the second material is greater than the thickness of the lines of the third material. 
     
     
         18 . The method of  claim 1 , further comprising depositing fifth material over the lines of the third material, wherein the first material and the third material are different. 
     
     
         19 . The method of  claim 18 , wherein the first material is the same as the fifth material. 
     
     
         20 . The method of  claim 18 , wherein the fifth material is deposited using atomic layer deposition. 
     
     
         21 . The method of  claim 18 , wherein depositing the fifth material fills spaces between adjacent lines of the third material. 
     
     
         22 . The method of  claim 21 , wherein depositing the fifth material forms a monolithic layer comprising the fifth material, the lines of the second material, and the lines of the third material. 
     
     
         23 . The method of  claim 1 , wherein providing the layer comprising the lines of the first material comprises providing a continuous layer of the first material and removing portions of the first material from the continuous layer to provide the lines of the first material. 
     
     
         24 . The method of  claim 1 , wherein the lines of the second and third materials form a grating that transmits 20% or more of light of wavelength λ having a first polarization state incident on the layer along a path, transmits 2% or less of light of wavelength λ having a second polarization state incident on the layer along the path, the first and second polarization states being orthogonal, and λ is 400 nm or less. 
     
     
         25 . The method of  claim 24 , wherein the grating has an extinction ratio of 20 dB or more for light at λ transmitted by the grating. 
     
     
         26 . The method of  claim 24 , wherein λ is in a range from 100 nm to 400 nm. 
     
     
         27 . The method of  claim 24 , wherein λ is about 266 nm, about 248 nm, about 193 nm, or about 157 nm. 
     
     
         28 . The method of  claim 1 , wherein the pairs of spaced-apart lines of the third materials are formed between alternating pairs of the lines of the second material. 
     
     
         29 . The method of  claim 28 , wherein the lines of the first material are positioned between pairs of lines of the second material between which no lines of the third material are formed. 
     
     
         30 . A method, comprising:
 forming a first conformal layer of a first material over a first grating comprising a plurality of lines of the second material different from the first material;   removing portions of the first conformal layer to provide a second grating comprising lines of the first material;   forming a second conformal layer of a third material over the second grating; and   removing portions of the second conformal layer to provide a third grating comprising lines of the third material and the lines of the first material,   wherein the third grating transmits 20% or more of light of wavelength λ having a first polarization state incident on the layer along a path, transmits 2% or less of light of wavelength λ having a second polarization state incident on the layer along the path, the first and second polarization states being orthogonal, and λ is 400 nm or less.   
     
     
         31 . An article, comprising:
 a layer extending in a plane, the layer comprising:   a plurality of spaced-apart lines of a first material extending along a first direction in the plane, each of the lines of the first material having a thickness, t 1 , along a second direction perpendicular to the plane;   a plurality of spaced-apart lines of a second material extending along the first direction, each of the lines of the second material having a thickness, t 2 , along the second direction, t 2  being less than t 1 , and each line of the second material being spaced-apart from a closest line of the first material,   wherein the first and second materials have a respective refractive index of 1.8 or more and a respective extinction coefficient of 1.8 or more for a wavelength λ that is 400 nm or less, and   the layer transmits 20% or more of light of wavelength λ having a first polarization state incident on the layer perpendicular to the plane, transmits 2% or less of light of wavelength λ having a second polarization state incident on the layer along the path, the first and second polarization states being orthogonal.   
     
     
         32 . A system, comprising:
 a light source configured to provide radiation at a wavelength λ during operation of the system;   a support apparatus configured to position a substrate to receive radiation provided by the light source; and   a polarizer positioned between the light source and the target, the polarizer comprising the article of  claim 31 .