Patent ID: 8238731

Claim:
A heat treatment apparatus for heating a substrate by light irradiation, comprising: a chamber having a tube-like inner wall with upper and lower openings; a holding part for holding a substrate in a horizontal position within said chamber; a first light-irradiation part provided on the upper side of said chamber and for irradiating the substrate held by said holding part with light; a second light-irradiation part provided on the lower side of said chamber and for irradiating the substrate held by said holding part with light; a first chamber window for closing the upper opening of said chamber and allowing the light emitted from said first light-irradiation part to pass through into said chamber; a second chamber window for closing the lower opening of said chamber and allowing the light emitted from said second light-irradiation part to pass through into said chamber; and a transport opening formed in the side wall of said chamber and for transporting a substrate into and out of said chamber, wherein an annular recessed portion is horizontally formed in the inner wall surface of said chamber to surround the periphery of said holding part, said recessed portion having a greater width in a vertical direction than said transport opening, and said transport opening communicates with the outer peripheral surface of said recessed portion.