High-precision magnetic levitation stage for photolithography

In this paper, we present a high-precision magnetic levitation (maglev) stage for photolithography in semiconductor manufacturing. This stage is the world's first maglev stage that provides fine six-degree-of-freedom motion controls and realizes large (50 mm x 50 mm) planar motions with only a single magnetically levitated moving part. The key element of this stage is a linear motor capable of providing forces in both suspension and translation without contact. The advantage of such a stage is that the mechanical design is far simpler than competing conventional approaches and, thus, promises faster dynamic response and higher mechanical reliability. The stage operates with a positioning noise as low as 5 nm rms in x and y, and acceleration capabilities in excess of 1 g (10 m/s(2)). We demonstrate the utility of this stage for next-generation photolithography or in other high-precision motion control applications. (C) 1998 Elsevier Science Inc.