| 摘要 |
Intense far-ultraviolet laser radiation is applied to a workpiece in performance of processes in the fabrication of integrated circuits, including processes of ablation, deposition, impurity implantation and radiation induced chemical processes. Other processes where intense far-ultraviolet laser radiation is applied include hardening and annealing a workpiece by exposure to the radiation. Particular embodiments of the invention herein enables selective removal of a polymer film on a semiconductor substrate by ablative photodecomposition (APD) using intense far-ultraviolet, or shorter wave length, radiation from a pulsed laser requires focusing the laser radiation to provide sufficiently high fluence of laser light energy to ablate a selected area of the polymer to a useful depth in a reasonable time, sometimes referred to as the threshold of fluence of the laser pulses required to produce effective APD of the polymer. This is done with a reflective objective lens system between the laser and the polymer film that focuses the laser beam on a target area of the film surface to a high fluence image of the beam exceeding the threshold for APD. All optical surfaces of the objective lens system are reflective and so are not damaged by the intense radiation as refractive lenses can be. In a preferred embodiment, the reflective objective lens system includes two reflectors, one large concave reflector with an entrance aperture at the center facing the target and one small centrally-located convex reflector facing away from the target. |
