Amplitude modulated electrostatic lithography using atomic force microscopy (AFM) on 20-50 nm thin polymer films is discussed. Electric bias of AFM tip increases the distance over which the surface influences the oscillation amplitude of an AFM cantilever, providing a process window to control tip-film separation. Arrays of nanodots, as small as 10-50 nm wide by 1-10 nm high are created via a localized Joule heating of a small fraction of polymer above the glass transition temperature, followed by electrostatic attraction of the polarized viscoelastic polymer melt toward the AFM tip in the strong (10(8)-10(9) V/m) nonuniform electric field. (C) 2003 American Institute of Physics.