Thermal anneal of block copolymer films with top interface constrained to wet both blocks with equal preference

1. A method of forming a nanostructured polymer material, comprising:

heating a substrate and a block copolymer material on the substrate to a temperature above a boiling point of an organic solvent to minimize swelling of the block copolymer material; and

thermally annealing the block copolymer material in a vapor of the organic solvent and at a temperature above the glass transition temperature (T g ) of the block copolymer material to cause polymer blocks of the block copolymer material to phase separate and self-assemble within a trench.

2. The method of claim 1 , wherein thermally annealing a block copolymer material in a vapor of an organic solvent and at a temperature above the glass transition temperature (T g ) of the block copolymer material comprises:

heating a first section of the block copolymer material to cause the first section to phase separate and self-assemble, and then subsequently heating remaining sections of the block copolymer material to cause the remaining sections to phase separate and self-assemble.

3. The method of claim 1 , wherein the trench comprises a neutral wetting floor and preferentially wetting sidewalls and ends.

4. The method of claim 3 , wherein the preferentially wetting sidewalls and ends of the trench comprises a material selected from the group consisting of silicon with native oxide, oxide, silicon nitride, silicon oxycarbide, indium tin oxide (ITO), silicon oxynitride, methacrylate resist, and polydimethylglutarimide resist.

5. The method of claim 3 , wherein the neutral wetting floor of the trench comprises a material selected from the group consisting of a random copolymer material, a blend of grafted homopolymers, and hydrogen-terminated silicon.

6. The method of claim 1 , wherein thermally annealing a block copolymer material in a vapor of an organic solvent and at a temperature above the glass transition temperature (T g ) of the block copolymer material comprises:

annealing the block copolymer material in a solvent vapor that is non-preferential to any polymer block.

7. The method of claim 1 , wherein thermally annealing a block copolymer material in a vapor of an organic solvent and at a temperature above the glass transition temperature (T g ) of the block copolymer material comprises:

annealing the block copolymer material in a partly saturated concentration of the organic solvent.

8. The method of claim 1 , wherein the block copolymer material comprises a cylindrical-phase block copolymer.

9. The method of claim 8 , wherein thermally annealing a block copolymer material in a vapor of an organic solvent and at a temperature above the glass transition temperature (T g ) of the block copolymer material comprises:

self-assembling the block copolymer material into cylinders of a first block within a matrix of a second block of the block copolymer material, the cylinders oriented perpendicular to and extending from a floor of the trench to an interface of the block copolymer material with the vapor of the organic solvent.

10. The method of claim 1 , wherein thermally annealing a block copolymer material in a vapor of an organic solvent and at a temperature above the glass transition temperature (T g ) of the block copolymer material comprises:

zone heating the block copolymer material in the vapor of the organic solvent to cause polymer blocks of the block copolymer material to phase separate and self-assemble within the trench.

11. The method of claim 1 , wherein thermally annealing a block copolymer material in a vapor of an organic solvent and at a temperature above the glass transition temperature (T g ) of the block copolymer material comprises:

zone heating a first section and then subsequent sections of the block copolymer material in the vapor of the organic solvent to cause the copolymer material phase to separate and self-assemble in the first section and then in the subsequent sections.

12. The method of claim 1 , wherein thermally annealing a block copolymer material in a vapor of an organic solvent and at a temperature above the glass transition temperature (T g ) of the block copolymer material comprises maintaining a concentration of the organic solvent in the air at a vapor interface with the block copolymer material at or under saturation.

13. The method of claim 1 , wherein thermally annealing a block copolymer material in a vapor of an organic solvent and at a temperature above the glass transition temperature (T g ) of the block copolymer material comprises globally heating the block copolymer material.

14. The method of claim 1 , wherein thermally annealing a block copolymer material in a vapor of an organic solvent and at a temperature above the glass transition temperature (T g ) of the block copolymer material comprises:

heating the block copolymer material above an order-disorder temperature of the block copolymer material; and

cooling the heated block copolymer material to below the order-disorder temperature but above the glass transition temperature of the block copolymer material.

15. The method of claim 1 , wherein the block copolymer material comprises a polymer selected from the group consisting of poly(styrene)-b-poly(vinylpyridine), poly(styrene)-b-poly(methyl methacrylate), poly(styrene)-b-polyacrylate, poly(styrene)-b-poly(methacrylate), poly(styrene)-b-poly(lactide), poly(styrene)-b-poly(tert-butyl acrylate), poly(styrene)-b-poly(ethylene-co-butylene), poly(styrene)-b-poly(ethylene oxide), poly(isoprene)-b-poly(ethyleneoxide), poly(isoprene)-b-poly(methyl methacrylate), poly(butadiene)-b-poly(ethyleneoxide), poly(styrene)-b-poly(ethylene oxide) copolymer having a cleavable junction between poly(styrene) and poly(ethylene oxide) blocks, poly(styrene)-b-poly(methyl methacrylate) doped with poly(ethylene oxide)-coated gold nanoparticles, poly(styrene)-b-poly(2-vinylpyridine) copolymer having a cleavable junction, poly(styrene)-b-poly(methyl methacrylate)-b-poly(ethylene oxide), poly(styrene)-b-poly(methyl methacrylate)-b-poly(styrene), poly(methyl methacrylate)-b-poly(styrene)-b-poly(methyl methacrylate), poly(styrene)-b-poly(isoprene)-b-poly(styrene), and combinations thereof.

16. A method of forming a nanostructured material, comprising:

forming a block copolymer material within a trench in a material layer overlying a substrate;

heating the substrate and the block copolymer material to a temperature above a boiling point of an organic solvent;

thermally annealing the block copolymer material in a vapor of the organic solvent and at a temperature above the glass transition temperature (T g ) of the block copolymer material to cause polymer blocks of the block copolymer material to phase separate and self-assemble;

selectively crosslinking a first block of the self-assembled block copolymer material;

selectively removing a second block of the self-assembled block copolymer material to form openings extending through the self-assembled block copolymer material; and

removing at least a portion of the substrate through the openings.

17. The method of claim 16 , wherein thermally annealing a block copolymer material in a vapor of an organic solvent and at a temperature above the glass transition temperature (T g ) of the block copolymer material comprises exposing the substrate to a temperature gradient, followed by cooling.

18. The method of claim 16 , wherein thermally annealing a block copolymer material in a vapor of an organic solvent and at a temperature above the glass transition temperature (T g ) of the block copolymer material comprises:

self-assembling the block copolymer material into at least one row of perpendicular-oriented cylinders of the second block within a matrix of the first block of the block copolymer material, with the perpendicular-oriented cylinders registered and parallel to sidewalls of the trench.

19. The method of claim 16 , wherein thermally annealing a block copolymer material in a vapor of an organic solvent and at a temperature above the glass transition temperature (T g ) of the block copolymer material comprises self-assembling the block copolymer material into cylindrical domains of the second block within a matrix of the first block of the block copolymer material, and

wherein selectively removing the second block of the self-assembled block copolymer material comprises removing the cylindrical domains of the second block to form openings extending through the self-assembled block copolymer material.

20. The method of claim 16 , further comprising, after removing at least a portion of the substrate through the openings,

removing the crosslinked first block of the self-assembled block copolymer material, and filling the openings with a fill material.

21. The method of claim 20 , wherein filling the openings with a fill material comprises filling the openings with a material selected from the group consisting of a metal, a metal alloy, and a metal-insulator-metal stack.