We are developing a Scanning Beam Interference Lithography (SBIL) system. SBIL represents a new paradigm in semiconductor metrology, capable of patterning large-area linear gratings and grids with nanometer overall phase accuracy. Realizing our accuracy goal is a major challenge because the interference fringes have to be locked to a moving substrate with nanometer spatial phase errors while the period of the fringes has to be stabilized to approximately one part per million. In this paper, we present a review of the SBIL design, and report recent progress towards prototyping the first-ever SBIL tool.© (2002) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.