Patent ID: 7148159

Claim:
An apparatus for performing laser thermal annealing of a substrate having a surface, comprising: a laser capable of generating continuous annealing radiation having a wavelength that is not substantially absorbed by the substrate at room temperature; an annealing optical system adapted to receive the annealing radiation and form an annealing radiation beam that forms a first image at the substrate surface, and wherein the first image is scanned across the substrate surface; and a heating device for heating at least a portion of the substrate to a critical temperature such that the annealing radiation beam incident upon said portion is substantially absorbed near the surface of the substrate at said portion during scanning; wherein the heating device includes: a preheating radiation source adapted to emit preheating radiation of a wavelength that is substantially absorbed by the substrate at room temperature; and a relay system adapted to receive the preheating radiation from the preheating radiation source and form a preheating radiation beam that forms and scans a second image over the substrate surface to preheat a portion of the substrate that is in front of or that partially overlaps the scanned first image.