Block copolymer lithography: Feature size control and extension by an over-etch technique, Thin Solid Films (2012), doi: 10.1016/j.tsf.2012.09.017 This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. ABSTRACT Block copolymer lithography based on block copolymer (BCP) self-assembly can be used to develop soft mask nanoscale templates for subsequent pattern transfer to generate substrate features. Self-assembly of lamellar polystyrene-b-polymethylmethacrylate BCP of varying molecular weights to generate silicon nanoscale features are reported here. It has also been demonstrated that the feature size can be controlled by a plasma over-etch process and discussed.