International Business Machines Corporation

Anindarupa Chunder

Ankit Vora

Joy Cheng

Daniel Sanders

Melia Tjio

Block polymers are formed by ring opening polymerization (ROP) of a cyclic carbonate monomer using a polymeric initiator for the ROP that comprises repeating functionalized ethylene units. The block polymers are free of, or substantially free of, any polymer having a chemical structure that does not comprise the polymer backbone of the polymeric initiator. The block polymers are capable of directed self-assembly.

Methods of forming block polymers for directed self-assembly

A film layer comprising a high-chi (&#x3c7;) block copolymer for self-assembly and a surface active polymer (SAP) was prepared on a substrate surface that was neutral wetting to the domains of the self-assembled block copolymer. The block copolymer comprises at least one polycarbonate block and at least one other block (e.g., a styrene-based block). The SAP comprises a hydrophobic fluorinated first repeat unit and a non-fluorinated second repeat unit bearing at least one pendent OH group present as an alcohol or acid (e.g., carboxylic acid). The film layer, whose top surface has contact with an atmosphere, self-assembles to form a lamellar or cylindrical domain pattern having perpendicular orientation with respect to the underlying surface. Other morphologies (e.g., islands and holes of height 1.0Lo) were obtained with films lacking the SAP. The SAP is preferentially miscible with, and lowers the surface energy of, the domain comprising the polycarbonate block.

Additives for orientation control of block copolymers

A film layer comprising a high-chi (&#x3c7;) block copolymer for self-assembly and a hexafluoroalcohol-containing surface active polymer (SAP) was prepared on a substrate surface that was neutral wetting to the domains of the self-assembled block copolymer. The block copolymer comprises at least one polycarbonate block and at least one other block (e.g., a substituted or unsubstituted styrene-based block). The film layer, whose top surface has contact with an atmosphere, self-assembles to form a lamellar or cylindrical domain pattern having perpendicular orientation with respect to the underlying surface. Other morphologies (e.g., islands and holes of height 1.0 Lo) were obtained with films lacking the SAP. The SAP is preferentially miscible with, and lowers the surface energy of, the domain comprising the polycarbonate block.

Fluoro-alcohol additives for orientation control of block copolymers

A film layer comprising a high-chi (&#x3c7;) block copolymer for self-assembly and a hexafluoroalcohol-containing surface active polymer (SAP) was prepared on a substrate surface that was neutral wetting to the domains of the self-assembled block copolymer. The block copolymer comprises at least one polycarbonate block and at least one other block (e.g., a substituted or unsubstituted styrene-based block). The film layer, whose top surface has contact with an atmosphere, self-assembles to form a lamellar or cylindrical domain pattern having perpendicular orientation with respect to the underlying surface. Other morphologies (e.g., islands and holes of height 1.0Lo) were obtained with films lacking the SAP. The SAP is preferentially miscible with, and lowers the surface energy of, the domain comprising the polycarbonate block.

An orientation control layer (OCL) for self-assembly of block copolymers comprises a random copolymer comprising a first repeat unit having an ethylenic backbone functional group and a side chain aromatic ring, a second repeat unit comprising an ethylenic backbone functional group and a side chain polycarbonate, and a third repeat unit comprising an ethylenic backbone functional group and a side chain ester or amide bearing an active group capable of forming a covalent bond with a substrate surface (e.g., a silicon wafer). The OCLs are neutral wetting to block copolymers having a high Flory-Huggins interaction parameter chi (&#x3c7;) ('high-chi' block copolymers) such as a block copolymer comprising a polystyrene block and a polycarbonate block. The neutral OCL wetting properties allow for formation of lamellar domain patterns of the self-assembled high-chi block copolymers to be oriented perpendicular to the OCL surface.

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San Jose, CA, United States of America

Anindarupa Chunder