Direct top-down ordering of diblock copolymers through nanoimprint lithography

In this work, thermal nanoimprint lithography (NIL) is used on full 8 in. silicon wafers to imprint a thin PS-b-PMMA block copolymer (BCP) layer. The authors show that the imprinted BCP layer can thermally self-organize after the NIL process or during the NIL process itself, depending on experimental conditions used. Self-organized imprinted features with good graphoepitaxy alignment are obtained with a cylindrical BCP. Nevertheless, a standard fluorinated silane mold treatment is shown not to be neutral to the BCP. Then, if the line features do not have a thickness exactly commensurable to the natural self-organizing period of the polymer l₀, a surface wetting layer is observed.