Block copolymer for lithography and lithography method using the same
The inventive concept relates to a block copolymer for lithography, capable of self-assembling and self-healing, and more particularly, to a block copolymer including a first block which is a repeating unit of polymerized siloxane and a second block which is a repeating unit of polymerized alkyl azobenzene acrylate. The alkyl is a linear or branched chain of 1 to 10 carbon atoms, the number (x) of the repeating unit of polymerized siloxane is about 60 to about 80, and the number (y) of the repeating unit of polymerized alkyl azobenzene acrylate is about 15 to about 25. The block copolymer has a cylindrical phase.
1 . A block copolymer for lithography, the block copolymer comprising:
a first block comprising a first repeating unit of Formula 1; and
a second block comprising a second repeating unit of Formula 2:
R 1 and R 2 are each independently hydrogen or a linear or branched C1-C10 alkyl group, and
“x” is an integer between 60 and 80,
R 3 is a linear or branched C1-C10 alkyl group,
“y” is an integer between 15 and 25, and
the block copolymer has a cylindrical phase.
2 . The block copolymer for lithography of claim 1 , wherein a ratio (y/x) of “y” to “x” is about 0.2 to about 0.3.
3 . The block copolymer for lithography of claim 1 , wherein a ratio of a volume of the first block to a volume of the block copolymer is about 0.45 to about 0.55.
4 . The block copolymer for lithography of claim 1 , wherein R 1 and R 2 are methyl groups.
5 . The block copolymer for lithography of claim 1 , wherein a line width of a cylindrical structure of the second block is about 8 nm to about 20 nm.
6 . A method for lithography comprising:
forming a polymer layer comprising a block copolymer on a substrate;
applying an electric field to the polymer layer to form a first nanostructure and a second nanostructure, the first nanostructure and the second nanostructure extending in a first direction and parallel to each other; and
selectively removing the first nanostructure,
wherein the block copolymer comprises:
a first block including a repeating unit of polymerized siloxane; and
a second block including a repeating unit of polymerized alkyl azobenzene acrylate,
the alkyl is a linear or branched chain of 1 to 10 carbon atoms,
a number (x) of the repeating unit of the polymerized siloxane is 60 to 80,
a number (y) of the repeating unit of the alkyl azobenzene acrylate is 15 to 25,
the first nanostructure comprises the first block, and
the second nanostructure comprises the second block.
7 . The lithography method of claim 6 , further comprising irradiating visible light to the first nanostructure and the second nanostructure, during or after applying the electric field.
8 . The lithography method of claim 6 , wherein the second nanostructure has a cylindrical structure formed using the second block.
9 . The lithography method of claim 8 , wherein the cylindrical structure extends horizontally in the first direction.
10 . The lithography method of claim 6 , wherein the forming of the polymer layer comprises spin coating a solution containing the block copolymer on the substrate.
11 . The lithography method of claim 6 , further comprising irradiating ultraviolet light to the block copolymer, before or during formation of the polymer layer.
12 . The lithography method of claim 6 , wherein a line width of each of the first nanostructure and the second nanostructure is about 8 nm to about 20 nm.
13 . The lithography method of claim 6 , wherein a ratio of a length of the second nanostructure in the first direction to a line width of the second nanostructure is about 300 to about 500.
14 . The lithography method of claim 6 , further comprising:
irradiating ultraviolet light to a damage region between the first nanostructure and the second nanostructure; and
applying an electric field again to the damage region to form at least one nanostructure extending in the first direction.
15 . A method of manufacturing a semiconductor device, the method comprising:
forming transistors on a substrate; and
forming wirings on the transistors, the wirings extending in a first direction,
wherein the forming of the wirings comprises:
forming an etch target layer on the transistors;
forming a polymer layer comprising a block copolymer on the etch target layer;
applying an electric field to the polymer layer to form first nanostructures and second nanostructures, the first nanostructures and the second nanostructures extending in the first direction and parallel to each other;
selectively removing the first nanostructures; and
patterning the etch target layer using the second nanostructures as an etching mask,
the block copolymer comprises:
a first block including a polymer of a silicon (Si) backbone; and
a second block including a repeating unit of polymerized monomers, each of the monomers comprising azobenzene,
a ratio of a volume of the first block to a volume of the block copolymer is about 0.45 to about 0.55,
each of the first nanostructures comprises the first block, and
each of the second nanostructures comprises the second block.
16 . The method of manufacturing a semiconductor device of claim 15 , wherein the first nanostructures and the second nanostructures are alternately arranged in a second direction which crosses the first direction.
17 . The method of manufacturing a semiconductor device of claim 15 , wherein the second nanostructures have a cylindrical structure formed using the second block.
18 . The method of manufacturing a semiconductor device of claim 15 , wherein a line width of each of the second nanostructures is about 8 nm to about 20 nm, and
a line width of each of the wirings is about 8 nm to about 20 nm.
19 . The method of manufacturing a semiconductor device of claim 15 , wherein a ratio of a length of the second nanostructures in the first direction to a line width of the second nanostructures is about 300 to about 500.
20 . The method of manufacturing a semiconductor device of claim 15 ,
wherein a degree of polymerization of the first block is 60 to 80, and
a degree of polymerization of the second block is 15 to 25.