Measurement of Light Emission from High Density Plasma Produced by Pulse Laser for Extreme-ultraviolet (EUV) Source

Abstract

We investigated the light emission from high density plasma produced by pulse laser, which is essential to extreme–ultraviolet (EUV) source for the next generation lithography. We measured EUV intensity and visible light emission from the plasma generated by focused laser to targets of three metals (Sn, Al, Cu) and two target shapes (flat, cone), using a photo diode senser with Si/Zr filter and a high–speed framing camera. The EUV emission from Sn target was highest. The duration of visible light emission from the cone shaped target was longer than that for flat target. These results suggest that the cone shaped Sn target is promising for the high power EUV light source application.