LASER THIN FILM POLY-SILICON ANNEALING OPTICAL SYSTEM

摘要

A high energy, high repetition rate workpiece surface heating method and apparatus are disclosed which may comprise a pulsed XeF laser operating operating at or above 4000 Hz and producing a laser output light pulse beam at a center wavelength of about 351 nm; an optical system narrowing the laser output light pulse beam to less than 20 [mu]m in a short axis of the laser output light pulse beam and expanding the laser output light pulse beam to form in a long axis of the beam workpiece covering extent of the long axis; the optical system including a field stop intermediate the laser and the workpiece; the workpiece comprising a layer to be heated; ; wherein the optical system focuses the laser output light pulse beam at a field stop with a magnification sufficient to maintain an intensity profile that has sufficiently steep side walls to allow the field stop to maintain a sufficiently steep beam profile at the workpiece without blocking the beam profile at too high an intensity level 2. The apparatus may also have a high average power in the laser output light pulse beam as delivered to the workpiece and a linebow correction mechanism in a short axis optical assembly. The linebow correction mechanism may comprise a plurality of weak cross cylinders. The system may comprise a catadioptric projection system. The line width due to laser diffraction and divergence may be less than geometric limitations.; The system may project adjacent peaks of the nominal XeF spectrum to improve overall depth of focus through the separate center wavelengths of each respective adjacent peak having a different focal plane at the workpiece. The system may comprise a linebow is correction mechanism within a field stop optical assembly correcting linebow at the field stop plane and within a workpiece projection optical assembly correcting linebow at the workpiece plane.