Patent ID: 8679255

Claim:
A gas supply device for supplying a processing gas into a processing chamber in which a target substrate is arranged, the processing gas being used for processing the target substrate, comprising: a gas introduction member provided in the processing chamber to face with the target substrate, the gas introduction member having gas inlet portions through which a gas containing the processing gas is introduced into the processing chamber; a processing gas supply unit configured to supply the processing gas into the gas introduction member; a processing gas supply path through which the processing gas flows from the processing gas supply unit; branch paths configured to supply the processing gas in a specific split flow rate ratio, the branch paths being branched off from the processing gas supply path and connected to the gas introduction member; an additional gas supply unit configured to supply an additional gas into the gas introduction member, the additional gas being used in adjusting processing characteristics of the processing gas; and an additional gas supply path connected to the additional gas supply unit and the gas introduction member, wherein the gas inlet portions include a first and a second gas inlet portion for supplying the processing gas toward a region where the target substrate is positioned and a third gas inlet portion for introducing the additional gas toward a region outside an outermost periphery portion of the target substrate, the branch paths being connected to the first and the second gas inlet portion, the additional gas supply path being connected to the third gas inlet portion, and a bypass passage that connects the additional gas supply path to one of the branch paths, and wherein the target substrate is processed by using the processing gas introduced through the first and the second gas inlet portion, and processing characteristics of the processing gas in the outmost periphery portion of the target substrate is adjusted by using the additional gas introduced through the third gas inlet portion.