Hierarchical nanostructures have been generated by combining a top-down ion beam lithography with a bottom-up self-assembly of block copolymer thin films.  The ion beam irradiated an array of micron-sized areas of a continuous copolymer film, containing self-ordered, uniform, few-nanometer sized microdomains.  Subsequent development produced a matrix of micron features, each consisting of an ordered array of block copolymer microdomains. For such a process, the copolymer may be chosen so that irradiation will selectively degrade one component, so that development leads to a pattern of nanopores within each of the irradiated features.   Examples to be shown include the use of 10-20 keV He or Ne ions on three different material systems:  PS-b-PMMA;  PS-b-PEO and PS-b-PEO/organosilicate hybrid.  Typical nanopore sizes were 20 nm in diameter, with pitch of 40 nm.

 

Further experiments will also be discussed, in which the ion beam is used to pre-pattern the substrate surface prior to deposition of the copolymer film, thus providing a matrix for directing self-assembly of the copolymer film. 

 

This approach provides a simple route to fabrication of ordered structures containing multiple length scales over large areas, with few-nanometer definition, which may assist a variety of potential future applications, such as multi-scale device lithography.

Ho-Cheol Kim, IBM Almaden Research Center, United States
John Baglin*, IBM Almaden Research Center, United States

*presenting author