Patent ID: 6815377
Filing Date: 2004-11-09
Classification: B23K,H01L

Abstract:
A laser annealing method, in which an amorphous silicon thin film to be converted from amorphous silicon into polycrystalline silicon is irradiated with a laser beam so as to convert the amorphous silicon into polycrystalline silicon, comprising:irradiating an amorphous silicon film sample with a laser beam under various energy density conditions so as to prepare a plurality of polycrystalline silicon film samples having different grain sizes, each polycrystalline silicon film sample having a corresponding energy density condition; allowing a light beam having a wavelength region including a visible wavelength in a center to be incident on said polycrystalline silicon film samples at a first angle relative to a line normal to a surface of the polycrystalline silicon film and detecting scattered light or reflected light at a second angle corresponding to a direction different from a direction of a regular reflection of said incident light so as to measure degrees of surface scattering of said plural polycrystalline silicon film samples and, thus, to obtain an energy density condition corresponding to a polycrystalline silicon film sample having a highest degree of scattering; adding a certain value of energy density to the energy density condition obtained in the preceding step so as to determine a set value of the energy density; and irradiating said amorphous silicon thin film to be converted from amorphous silicon into polycrystalline silicon with a laser beam at the set value of the energy density determined in the preceding step so as to carry out the laser annealing.