System and process learning in a full-field, high-power EUVL alpha tool

ABSTRACT Full-field imaging with a developmental projection optics box (POB1) was successfully demonstrated in the alpha-tool Engineering Test Stand (ETS) last year. Many improvements in the ETS have been made to prepare for operation as a major component of the Resource Development Center (RDC). These improvements include upgrading the optics with a lower flare, better figure, projection optics box (POB2), developing a more reliable source, implementing lower jitter stages, adding EUV sensors, and installing a more flexible control system. The net result has been improved lithographic performance, with better image quality, improved reliability, improved throughput, and scanned features of 70 nm. This paper reports on ETS system upgrades and the impact on system performance. Keywords: EUVL, extreme ultraviolet, lithography, optical fabrication, optical design, laser-produced plasma, laser plasma source, maglev, magnetic levitation, precision engineering 1. INTRODUCTION The Engineering Test Stand (ETS) was designed as a full-field, extreme ultraviolet (EUV) imaging system to provide early learning for critical issues on EUV lithography (EUVL) and to demonstrate the feasibility of EUVL. It has proven to be a useful tool for acquiring the learning needed to develop commercial EUVL tools. Last year the ETS demonstrated the printing of 90-nm-resolution scanned images using a high-power (500 W) laser and a developmental projection optics system, POB1.