Patent ID: 8575515

Claim:
A laser annealing apparatus that performs an annealing treatment on a workpiece to be processed by irradiating the workpiece with laser light, wherein apparatus comprises: (a) a gas supply unit that supplies an inert gas to at least a laser irradiation area of a workpiece, wherein the gas supply unit includes a purge box that has a bottom surface that is a flat surface parallel to a surface of the workpiece, wherein the bottom surface of the purge box is disposed so as to face the surface of the workpiece and the inert gas is introduced into the purge box; (b) a laser light source that emits laser light; and (c) a gas temperature controller that controls the temperature of the inert gas in a supply area, wherein the purge box includes i. a transmission window that transmits the laser light so the laser light is introduced into the purge box; and ii. an opening provided in the bottom surface of the purge box that passes the laser light introduced into the purge box through the purge box and the inert gas inside the purge box blows through the opening towards the workpiece, and wherein the inert gas blowing through the opening of the purge box forms a purge area between the bottom surface of the purge box and the surface of the workpiece, and the gas temperature controller controls the temperature of the inert gas supplied to the laser irradiation area of the workpiece so as to decrease a temperature difference between the temperature of the inert gas and an atmospheric temperature of a space disposed outside the supply area of the inert gas so as to surround an optical path of the laser light with the temperature controlled inert gas.