Laser bandwidth reduction, for an excimer laser used for semiconductor wafer lithography, divides the laser beam into two part-beams to strike the end reflector at different angles

摘要

The system is for the reduction of the bandwidth of a laser (40), especially an excimer laser, where the laser beam (58) oscillates in a resonator between a catcher (42) and an end reflector (44) with wavelength selection as a diffraction grid. The laser beam is divided into two part-beams (60,62), with deflection so that they strike the end reflector at different and overlapping angles (alpha , alpha +delta ). The angles are adjusted according to the wavelength to be amplified, so that the part-beams are reflected inside against each other.