We investigate poly (methylmethacrylate) (PMMA) development processing with cold developers (4 - 10 degreesC) for its effect on resolution, resist residue, and pattern quality of sub-10 nm electron beam lithography (EBL). We find that low-temperature development results in higher EBL resolution and improved feature quality. PMMA trenches of 4-8 nm are obtained reproducibly at 30 kV using cold development. Fabrication of single-particle-width An nanoparticle lines was performed by lift-off. We discuss key factors for formation of PMMA trenches at the sub-10 nm scale. (C) 2004 American Vacuum Society.