Laser-Produced Plasma Light Source Development for Extreme Ultraviolet Lithography
Hiroshi Komori, Georg Soumagne, Tamotsu Abe, Takashi Suganuma, Yousuke Imai, Hiroshi Someya, Y. Takabayashi, Akira Endo, K. Toyoda
Japanese Journal of Applied Physics · 2004 · 인용 14
We present recent results of our laser-produced plasma light source development for next-generation lithography. The plasma target of the extreme ultraviolet (EUV) source system is a liquid xenon jet and the driver laser is a 600 W Nd:YAG laser operating at a repetition rate of 10 kHz. A EUV output power of 2.2 W at 13.5 nm (2% bandwidth, 2π sr) having a stability of 0.72% (1σ, 50-pulse moving average) has been achieved.
Related to future collector mirror lifetime considerations, fast ions from the laser-produced plasma have been characterized by time-of-flight (TOF) measurements. Using a low repetition rate 8-ns, 100-mJ Nd:YAG laser Xe + to Xe 6+ ions were observed with Xe 2+ being the main charge state. In addition, the effects of fast ions on Mo/Si multilayer mirrors have been studied using a Xe ion gun.
Ion sputtering of the multilayer structure is the main damage mechanism but layer boundary mixing and surface roughness increase are also observed.