Methods of patterning block copolymer layers and patterned structures

1. A method of patterning a block copolymer layer, the method comprising:

providing a substrate comprising a topographic pattern on a surface of the substrate, wherein the topographic pattern comprises a trench and a mesa;

forming, on the surface of the substrate, an underlayer comprising a polymer, having an anchoring group,

wherein the polymer consists of a first repeating unit derived from a substituted or unsubstituted aromatic vinyl monomer or a combination of the first repeating unit and a second repeating unit derived from at least one non-aromatic vinyl monomer selected from a substituted or unsubstituted C1 to C10 alkyl(meth)acrylate, and a substituted or unsubstituted C6 to C20 aryl(meth)acrylate;

heat-treating the underlayer to anchor the underlayer to the surface of the substrate via the anchoring group;

irradiating the heat-treated underlayer with light to form a crosslinked polymer with a crosslink between carbon atoms of main chains of the polymer, wherein an aromatic group of the first repeating unit is directly linked to a main chain carbon atom of the polymer;

forming a block copolymer layer on the underlayer comprising the crosslinked polymer; and

heat-treating the block copolymer layer to form a self-assembled structure of the block copolymer directed by the topographic pattern,

wherein the light in the irradiating the heat-treated underlayer is a UV light having a wavelength of shorter than or equal to about 300 nanometers,

wherein the anchoring group is selected from a hydroxyl group, a thiol group, an azide group, a carboxylic acid group, an amide group, an amine group, or a trichlorosilane group, and

wherein the anchoring group is disposed at a main chain carbon atom of the terminal end of the polymer.

2. The method of claim 1 , wherein the polymer in the underlayer comprises a repeating unit derived from a vinyl monomer comprising a substituted or unsubstituted benzene moiety, a substituted or unsubstituted naphthalene moiety, a substituted or unsubstituted anthracene moiety, a substituted or unsubstituted pyridine moiety, a substituted or unsubstituted pyrrole moiety, a substituted or unsubstituted furan moiety, or a substituted or unsubstituted thiophene moiety.

3. The method of claim 1 , wherein the polymer in the underlayer comprises a repeating unit derived from a substituted or unsubstituted styrene, a substituted or unsubstituted vinyl naphthalene, a substituted or unsubstituted vinylanthracene, a substituted or unsubstituted vinylpyridine, a substituted or unsubstituted vinylpyrrole, a substituted or unsubstituted vinylfuran, a substituted or unsubstituted vinylthiophene, or a combination thereof.

4. The method of claim 1 , wherein the polymer in the underlayer comprises a repeating unit derived from styrene, a C1 to C10 alkyl substituted styrene, a halogen substituted styrene, 1-vinylpyrrole, 2-vinylpyrrole, 3-vinylpyrrole, 2-vinylpyridine, 4-vinylpyridine, 2-vinylfuran, 3-vinylfuran, 2-vinylthiophene, 3-vinylthiophene, or a combination thereof.

5. The method of claim 1 , wherein the polymer in the underlayer is a homopolymer, a random copolymer, or a block copolymer.

6. The method of claim 1 , wherein the polymer in the underlayer is a hydroxy-terminated polystyrene, a hydroxy-terminated poly(methylstyrene), a hydroxy-terminated poly(ethylstyrene), a hydroxy-terminated poly(4-t-butylstyrene), a hydroxy-terminated poly(chlorostyrene), a hydroxy-terminated poly(2-vinylpyridine), a hydroxy-terminated poly(4-vinylpyridine), a hydroxy-terminated poly(1-vinylpyrrole), a hydroxy-terminated poly(2-vinylpyrrole), a hydroxy-terminated poly(vinylpyrrole), a hydroxy-terminated poly(methylmethacrylate-co-styrene) random copolymer, a hydroxy-terminated poly(styrene-co-vinylpyridine) random copolymer, a hydroxy-terminated poly(methylmethacrylate-co-vinylpyridine) random copolymer, or a combination thereof.

7. The method of claim 1 , wherein the heat-treating the underlayer is conducted at a temperature of greater than or equal to about 80° C. for about 30 minutes or longer.

8. The method of claim 1 , further comprising

washing the heat-treated underlayer with an organic solvent prior to the irradiating the heat-treated underlayer with light.

9. The method of claim 8 , wherein the organic solvent is a C6 to C20 aromatic hydrocarbon, a C5 to C10 aliphatic hydrocarbon, a ketone, or a combination thereof.

10. The method of claim 1 , wherein the irradiating the heat-treated underlayer with light is conducted at a light intensity of greater than or equal to about 10 Joules/centimeter 2 .

11. The method of claim 1 , wherein the block copolymer comprises

a block copolymer comprising a first repeating unit comprising styrene or a derivative thereof and a second repeating unit comprising (meth)acrylic acid ester,

a block copolymer comprising a first repeating unit comprising styrene or a derivative thereof and a second repeating unit comprising siloxane or a derivative thereof,

a block copolymer comprising a first repeating unit comprising styrene or a derivative thereof and a second repeating unit comprising an olefin, or

a block copolymer comprising a first repeating unit comprising styrene or a derivative thereof and a second repeating unit comprising an alkylene oxide.

12. The method of claim 1 , wherein the block copolymer self-assembled by the heat-treating of the block copolymer layer comprises a cylinder structure parallel to the substrate or a lamella structure perpendicular to the substrate.

13. The method of claim 1 , wherein a thickness of the block copolymer layer is greater than or equal to 15 nanometers so that a self-assembled structure of the block copolymer is directed by the topographic pattern both in the trench and on the mesa.

14. The method of claim 1 , wherein a thickness of the underlayer is substantially equal to a depth of the trench so that a self-assembly of the block copolymer is directed in a direction orthogonal to the topographic pattern.

15. A patterned polymer structure including

a substrate,

an underlayer disposed on a surface of the substrate, and

a block copolymer layer patterned on the underlayer,

wherein the underlayer comprises a crosslinked polymer consisting of a first repeating unit derived from a substituted or unsubstituted aromatic vinyl monomer or a combination of the first repeating unit and a second repeating unit derived from at least one non-aromatic vinyl monomer selected from a substituted or unsubstituted C1 to C10 alkyl(meth)acrylate, and a substituted or unsubstituted C6 to C20 aryl(meth)acrylate,

the crosslinked polymer is linked to the substrate via a moiety derived from an anchoring group,

wherein the crosslinked polymer comprises a crosslink between carbon atoms of a main chain of the polymer, and an aromatic group of the first repeating unit is directly linked to a carbon atom of the main chain of the polymer,

wherein the anchoring group is selected from a hydroxyl group, a thiol group, an azide group, a carboxylic acid group, an amide group, an amine group, or a trichlorosilane group, and

wherein the anchoring group is disposed at a main chain carbon atom of the terminal end of the polymer.