Current Status of the EUV Engineering Test Stand.

Abstract

The EUV Engineering Test Stand (ETS) has demonstrated the printing of static and scanned 100 nm dense features. This milestone was first achieved in 2001 with a developmental set of projection optics (P0 Box 1) and with a low power LPP source (40W drive laser). Since that time, the source has been upgraded to a 1500W (3 chains, 500W per chain) TRW drive laser. Operating with one chain (500W), the printed static images for 100 nm features are comparable to those obtained with the low power source, while exposure time was decreased by a factor of 15 to 30. One hundred nanometer dense features printed in step-and-scan mode are of the same image quality as those obtained in static imaging. The stages have demonstrated combined x any y j fitter values of 2 to 4 nm RMS over most of the wafer stage travel range, at the designed scanned speed of 10 mm/s at the wafer. This value is less than half of the designed value and provides sufficient stability to support printing of 70 nm features. EUV specific sensors at the wafer and reticle planes have been demonstrated with the TRW laser and integration will be completed later this year. The developmental projection optics (P0 Box 1) will be replaced later this year with an improved projection optics system (P0 Box 2) capable of printing 70 nm dense features.