Neutral layer polymers, methods of manufacture thereof and articles comprising the same
View Patent ↗Disclosed herein is a block copolymer comprising a first segment and a second segment that are covalently bonded to each other and that are chemically different from each other; where the first segment has a first surface free energy and where the second segment has a second surface free energy; and an additive copolymer; where the additive copolymer comprises a surface free energy reducing moiety where the surface free energy reducing moiety has a lower surface free energy than that of the first segment and the second segment; the additive copolymer further comprising one or more moieties having an affinity to the block copolymer; where the surface free energy reducing moiety is chemically different from the first segment and from the second segment; where the additive copolymer is not water miscible; and where the additive copolymer is not covalently bonded with the block copolymer.
1. A composition comprising:
a block copolymer comprising a first segment and a second segment that are covalently bonded to each other and that are chemically different from each other; where the first segment has a first surface free energy and where the second segment has a second surface free energy;
an additive copolymer; where the additive copolymer comprises a surface free energy reducing moiety where the surface free energy reducing moiety has a lower surface free energy than that of the first segment and the second segment; the additive copolymer further comprising one or more moieties having an affinity to the block copolymer; where the surface free energy reducing moiety is chemically different from the first segment and from the second segment; where the additive copolymer is not water miscible; where the additive copolymer is not covalently bonded with the block copolymer; and where the additive copolymer is operative to form a neutral layer on a surface of the block copolymer and to facilitate formation of domains in the block copolymer that are perpendicular to a surface of a substrate that the composition is disposed on; where the surface free energy reducing moiety is covalently bonded to a segment that is chemically identical or chemically compatible with the first segment of the block copolymer, or to a segment that is chemically identical or chemically compatible with the second segment of the block copolymer; and
a solvent.
2. The composition of claim 1 , where the surface free energy reducing moiety comprises a fluorine atom, a silicon atom, an unsubstituted or substituted C 1 -C 12 hydrocarbyl, or a combination thereof.
3. The composition of claim 1 , wherein the solvent is a mixture comprising an additive solvent and a primary solvent, wherein the additive solvent is present in an amount less than the primary solvent, and wherein the additive solvent has a lower evaporation rate than the primary solvent.
4. The composition of claim 1 , where the additive copolymer comprises a first additive copolymer and a second additive copolymer, where the first additive copolymer is not covalently bonded to the second additive copolymer; where the first additive copolymer comprises a first surface free energy reducing moiety and where the second additive copolymer comprises a second surface free energy reducing moiety; where the first surface free energy reducing moiety and the second surface free energy reducing moiety are the same or different from each other.
5. The composition of claim 1 , where at least one moiety of the additive copolymer is chemically identical with the first segment or with the second segment of the block copolymer.
6. The composition of claim 1 , where the additive copolymer is a block or a graft copolymer.
7. The composition of claim 1 , where the block copolymer comprises polysiloxane and polystyrene and where the additive copolymer comprises poly(methyl methacrylate-random-trifluoroethyl methacrylate).
8. The composition of claim 1 , where the block copolymer comprises polystyrene and poly(2-vinylpyridine) and where the additive copolymer comprises poly(1,1,1,3,3,3-hexafluoroisopropyl methacrylate)-block-poly(methyl methacrylate).
9. A method comprising:
disposing on a substrate a composition comprising:
a block copolymer comprising a first segment and a second segment that are covalently bonded to each other and that are chemically different from each other; where the first segment has a first surface free energy and where the second segment has a second surface free energy;
an additive copolymer; where the additive copolymer comprises a surface free energy reducing moiety where the surface free energy reducing moiety has a lower surface free energy than that of the first segment and the second segment; the additive copolymer further comprising one or more moieties having an affinity to the block copolymer; where the surface free energy reducing moiety is chemically different from the first segment and from the second segment; where the additive copolymer is not water miscible; where the additive copolymer is not covalently bonded with the block copolymer; and where the additive copolymer is operative to form a neutral layer on a surface of the block copolymer and to facilitate formation of domains in the block copolymer that are perpendicular to a surface of the substrate that the composition is disposed on; where the surface free energy reducing moiety is covalently bonded to a segment that is chemically identical or chemically compatible with the first segment of the block copolymer, or to a segment that is chemically identical or chemically compatible with the second segment of the block copolymer; and
a solvent.
10. The method of claim 9 , further comprising annealing the composition.
11. The method of claim 9 , further comprising removing the neutral layer to expose the underlying block copolymer and selectively removing portions of the block copolymer to form a patterned resist layer.