Dimensional metrology for nanometre-scale science and engineering: towards sub-nanometre accurate encoders

Metrology is the science and engineering of measurement. It has played a crucial role in the industrial revolution at the milli-inch length scale and in the semiconductor revolution at the micrometre length scale. It is often proclaimed that we are standing at the threshold of another industrial revolution, brought by the advent and maturing of nanotechnology. We argue that for nanotechnology to have a similarly revolutionary effect a metrology infrastructure at and below the nanometre scale is instrumental and has yet to be developed. This paper focuses on dimensional metrology, which concerns itself with the measurement of lengths and its applications such as pattern placement and feature size control. We describe our efforts to develop gratingand grid-based scales with sub-nanometre accuracy over 300 mm dimensions using the nanoruler—a scanning-beam interference lithography tool. (Some figures in this article are in colour only in the electronic version)