LASER MATERIAL REMOVAL METHODS AND APPARATUS

摘要

Embodiments of the present invention generally provide methods and apparatus for material removal using lasers in the fabrication of solar cells. In one embodiment, an apparatus is provided that precisely removes portions of a dielectric layer deposited on a solar cell substrate according to a desired pattern and deposits a conductive layer over the patterned dielectric layer. In one embodiment, the apparatus also removes portions of the conductive layer in a desired pattern. In certain embodiments, methods for removing a portion of a material via a laser without damaging the underlying substrate are provided. In one embodiment, the intensity profile of the beam is adjusted so that the difference between the maximum and minimum intensity within a spot formed on a substrate surface is reduced to an optimum range. In one example, the substrate is positioned such that the peak intensity at the center versus the periphery of the substrate is lowered. In one embodiment, the pulse energy is improved to provide thermal stress and physical lift-off of a desired portion of a dielectric layer.