Dual brush process for selective surface modification in grapho-epitaxy directed self-assembly

摘要

Grapho-epitaxy directed self-assembly is a potential low-cost solution for patterning via layers with pitches beyond the reach of a single optical lithographic exposure. In this process, selective control of the interfacial energy at the bottom and sidewall of the template is an important but challenging exercise. In this work, a dual brush process is implemented, in which two brushes with distinct end-groups are consecutively grafted to the pre-pattern to achieve fully independent modification of the bottom and sidewall surface of the template. A comprehensive study of hole pattern quality shows that using a dual brush process leads to a substantial improvement in terms of positional and dimensional variability across the process window. These findings will be useful to others who wish to manipulate polymer-surface interactions in directed self-assembly flows.