Prospects of semiconductor lithography

Abstract

Lithography technologies have overcome many barriers over the years as the driving force behind the semiconductor technology roadmap. It appears, however, that they are now running into a very formidable barrier. The key technology at present is optical lithography using KrF (248 nm) and ArF (193 nm) excimer lasers as light sources, and this technology along with innovative mask and resist technologies has made the mass production of 65‐nm nodes possible. In contrast, the coming of next‐generation lithography has been delayed despite the original expectation for its early implementation. The key technology for producing nodes of 45‐nm nodes and beyond still awaits realization. Candidates for this next‐generation lithography appear regularly, however, and the field is now saturated with many candidates. These are generally divided into short‐wavelength optical lithography from the F2laser (157 nm) to the EUV (13.5 nm) and electron beam lithography. In particular, immersion lithography technology has attracted considerable interest recently, and research to extend. ArF excimer laser and F2laser lithography technologies has been quite active. There is also discussion about applying imprint lithography, which was originally used in the nanotechnology field, in to semiconductor fabrication and miniaturization. In this report, we describe the current state of optical lithography technologies and trends in next‐generation lithography technologies in reference to worldwide developments, and discus future directions in semiconductor miniaturization.