Patent ID: 7833350

Claim:
An apparatus for treating a substrate, comprising: a stage adapted to receive the substrate; a gas shield facing said substrate, said gas shield having a retention space and having top, middle and bottom plates with first, second, and third unconnected gas paths disposed therein, said gas paths each having an introduction port through which gas is introduced and an exit port from which the gas exits, wherein said retention space is surrounded by inner surfaces of said top, middle and bottom plates, wherein said first gas path is located on a top surface of said middle plate, wherein said top surface of said middle plate is parallel to said stage, and the exit port of said first gas path directly meets a middle space of said retention space, wherein said middle space is surrounded by said inner surface of said middle plate; an energy source facing said top plate such that light emitted therefrom irradiates a part of said Substrate through said retention space; a reaction gas supplier connected to said first gas path to supply reaction gas to said middle space; and first and second pumps connected to said second and third gas paths, respectively, wherein said first pump is capable of inhaling gas from and exhaling gas to said second gas path and said second pump is capable of inhaling gas from and exhaling gas to said third gas path, wherein further comprising an inert gas supplier and an inert gas path in said gas shield, said inert gas supplier connected to said inert gas path, wherein said reaction gas supplier and said inert gas supplier are introduced to the gas plates through different introduction ports in said top plate and connected to said retention space through different grooves in said top surface of said middle plate, and wherein said different grooves in the top surface of said middle plate directly meet the middle space of said retention space to directly supply the reaction gas from the reaction gas supplier and said inert as from said inert gas supplier to said middle space of said retention space, wherein the gas shield further includes a heating plate surrounding said retention space and sandwiched between at least one of said top plate and said middle plate or between said middle plate and said bottom plate.