Laser-produced plasmas for soft x-ray projection lithography

Laser-produced plasmas are one of the most likely sources to be used for soft x-ray projection lithography. The characteristics of these sources are described in terms of the expected radiation efficiency within the illumination bandwidth of a lithographic system. Measurements of the plasma particulate emission are described and techniques for interdicting this emission before it reaches the illumination optics are discussed. The laser requirements are obtained for a lithographic system producing a wafer rate of 60, 6 in. wafers per hour.