EXCIMER-LASER WITH HIGH-REPETITION-RATE FOR DUV LITHOGRAPHY

The 248nm wavelength of the KrF excimer laser is the accepted tool for the production of structures in the range of 0.25 mu m. When going to below 0.20 mu m, the even shorter excimer wavelength of 193nm will be used. The demands on the laser source have changed over the last year s for both the reflective and the refractive Step&Scan tools. The cost -effective operation of such lithography tool requires excimer lasers with high power and repetition rates of greater than or equal to 1kHz. Precise dose control of the exposure requires high repetition rate an d stability of the laser output energy.