Method of forming sub-lithographic features using directed self-assembly of polymers

A method, comprising:

• providing a plurality of substrates each of which has openings whose targeted diameter is less than 200 nm, wherein the targeted diameter is the same for each of the substrates, the openings having average diameters having a statistical variation, for all of said openings in said substrates, characterized by a standard deviation σopenings and an average diameteropenings, with 3σopenings being at least 10% of the targeted diameter;
• applying, over each of the substrates, a layer of polymer that includes a block copolymer, wherein components of the copolymer are immiscible with one another;
• allowing the polymer to form, inside each of the openings in each of the substrates, a self-assembled central domain within a surrounding self-assembled domain;
• and
• selectively removing the central domains in each of the substrates, thereby forming a hole where each central domain was located, the holes having respective diameters and a statistical variation in their diameters, for all of said holes in said substrates, characterized by a standard deviation σholes and an average diameterholes;
• wherein σholes/average diameterholes is less than 0.8 of σopenings/average diameteropenings.

A method, comprising:

• providing a substrate having a surface with an opening therein, the opening having a boundary equivalent to that formed from overlapping holes whose targeted diameter is less than 200 nm, the holes having sidewalls that define protrusions where the sidewalls adjoin, the overlapping holes having respective diameters and a statistical variation in their diameters characterized by a standard deviation σoverlapping holes and an average diameteroverlapping holes;
• applying, over the surface, a layer of polymer that includes a block copolymer, wherein components of the copolymer are immiscible with one another;
• allowing the polymer to form a single discrete, segregated domain inside each portion of the opening corresponding to one of the holes, and
• removing at least some of the discrete, segregated domains, thereby forming holes, the formed holes having respective diameters and a statistical variation in their diameters characterized by a standard deviation σformed holes and an average diameterformed holes, wherein:
• i) the position of each discrete, segregated domain is predetermined by at least one sidewall and a protrusion that forms at least part of said at least one sidewall,
• ii) the domains have respective geometric centers, and for any given domain, its center and the center of the given domain's nearest neighbor are separated by a distance that is less than the sum of the average radii of curvature of the holes corresponding to the sidewalls that predetermine the positions of the given domain and the given domain's nearest neighbor, and
• iii) σformed holes/average diameterformed holes is less than σoverlapping holes/average diameteroverlapping holes.