Orientation control layer formed on a free top surface of a first block copolymer from a mixture of first and second block copolymers
View Patent ↗Disclosed herein is a method comprising disposing a first composition comprising a first block copolymer upon a substrate; where the first block copolymer comprises 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 disposing a second composition comprising an second copolymer upon a free surface of the first block copolymer; where the second copolymer comprises a surface free energy reducing moiety; where the surface free energy reducing moiety has a lower surface free energy than the first surface free energy and the second surface free energy; the second copolymer further comprising one or more moieties having an affinity to the first block copolymer; where the surface free energy reducing moiety is chemically different from the first segment and from the second segment.
1. A method comprising:
disposing a first composition comprising a first block copolymer and a second copolymer upon a substrate; where the first block copolymer comprises 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
where the second copolymer comprises a surface free energy reducing moiety; where the surface free energy reducing moiety has a lower surface free energy than the first surface free energy and the second surface free energy; the second copolymer further comprising one or more moieties having an affinity to the first block copolymer; where the surface free energy reducing moiety is chemically different from the first segment and from the second segment; and where the second copolymer contacts the top free surface of the first block copolymer.
2. The method of claim 1 , where the second copolymer is operative to form an orientation control layer on a surface of the composition and to facilitate formation of microdomains in the first block copolymer that are perpendicular to a surface of the substrate that the composition is disposed on.
3. The method of claim 1 , where the surface free energy reducing moiety is covalently bonded to a plurality of the same monomers that comprise the first segment and/or to the same monomers that comprise the second segment.
4. The method of claim 1 , where the second copolymer comprises a blend of copolymers, each of which comprises a surface free energy reducing moiety that is covalently bonded to a plurality of the same monomers that comprise the first segment and/or to the same monomers that comprise the second segment.
5. The method of claim 1 , where the first composition further comprises a solvent that is immiscible with the first block copolymer.
6. The method of claim 1 , further comprising an annealing step.
7. The method of claim 2 , further comprising removing the orientation control layer to expose the underlying block copolymer.
8. The method of claim 7 , further comprising selectively removing portions of the block copolymer to form a patterned resist layer.