Solvent annealing block copolymers on patterned substrates
Provided herein are block copolymer thin film structures and methods of fabrication. Aspects described herein include methods of directed self-assembly of block copolymers on patterns using solvent annealing, and the resulting thin films, structures, media or other compositions. According to various embodiments, solvent annealing is used direct the assembly of block copolymers on chemical patterns to achieve high degrees of pattern perfection, placement of features at the precision of the lithographic tool used to make the chemical pattern, improved dimensional control of features, improved line edge and line width roughness, and resolution enhancement by factors of two to four or greater.
1. A method comprising:
providing a substrate pattern;
depositing a block copolymer material on the substrate pattern; and
inducing the formation of microphase-separated domains in the block copolymer material by solvent annealing, wherein the substrate pattern has a pattern period (L s ) between 0.8 and 1.2 times a vitrified microdomain period of the block copolymer material in the solvent (L v ).
2. The method of claim 1 , wherein L v is not equal to the bulk period L o of the block copolymer material.
3. The method of claim 1 , wherein L v is less than the bulk period L o of the block copolymer material.
4. The method of claim 1 , wherein L v is greater than the bulk period L o of the block copolymer material.
5. The method of claim 1 , wherein the substrate pattern includes at least one feature having an effective pattern period that differs from L s .
6. The method of claim 1 , further comprising evaporating the solvent.
7. The method of claim 1 , further comprising, prior to providing the substrate pattern, determining L v .
8. The method of claim 1 , wherein the solvent is selected from methanol, acetone, carbon disulfide, dimethylformamide, toluene, and tetrahydrofuran.
9. The method of claim 1 , wherein all of the polymer blocks of the block copolymer material are soluble in the solvent.
10. The method of claim 1 , wherein at least one of the polymer blocks of the block copolymer material is insoluble in the solvent.
11. The method of claim 1 , wherein the microphase-separated domains are registered with the substrate pattern.
12. The method of claim 1 , wherein the microphase-separated domains are oriented substantially perpendicular to the substrate.
13. The method of claim 12 , wherein the microphase-separated domains extend through the entire thickness of the block copolymer material.
14. The method of claim 1 , wherein L s is between 0.9 L v and 1.1L v .
15. The method of claim 1 , wherein the interaction parameter (χ) of a block copolymer in the block copolymer material is larger than that of PS-b-PMMA at the temperature of assembly.
16. The method of claim 1 , wherein the solvent annealing is performed at room temperature.
17. A method comprising:
providing a block copolymer film on a substrate pattern;
exposing the block copolymer film on the substrate pattern to a solvent to thereby direct the assembly of the block copolymer film while the block copolymer film is in a solvated and microphase-separated state such that the block copolymer film has assembled domains having dimensions in x- and y-directions, the x- and y-directions being parallel to an underlying substrate; and,
after directing the assembly of the block copolymer film, evaporating the solvent such that the assembled domains are in a vitrified state, wherein the x- and y-dimensions of the assembled domains in the vitrified state are the same as the x- and y- dimensions of the assembled domains in the solvated state.
18. The method of claim 17 , wherein the assembled block copolymer film has smaller features than the bulk block copolymer.
19. The method of claim 17 , wherein the density of features in the assembled block copolymer film is greater than the substrate pattern density.