Patent ID: 8701593
Filing Date: 2014-04-22
Classification: C23C,Y10T

Abstract:
1. A gas supply system for supplying a gas into a processing chamber through a plurality of buffer chambers for processing a substrate to be processed, the system comprising: a processing gas supply unit for supplying processing gas for processing the substrate to be processed; a processing gas supply line for allowing the processing gas from the processing gas supply unit to flow therein; a first and a second processing gas branch line branched from the processing gas supply line, wherein the buffer chambers include a first and a second buffer chamber, the first processing gas branch line is connected to the first buffer chamber, and the second processing gas branch line is connected to the second buffer chamber; a branch flow control unit for controlling branch flows of the processing gas distributed from the processing gas supply line to the first and the second processing gas branch line based on inner pressures of the first and the second processing gas branch line, respectively; an additional gas supply unit for supplying additional gas; an additional gas supply line for allowing the additional gas from the additional gas supply unit to flow therein; a first additional gas branch line branched from the additional gas supply line to be connected with the first processing gas branch line at a downstream side of the branch flow control unit; a second additional gas branch line branched from the additional gas supply line to be connected with the second processing gas branch line at a downstream side of the branch flow control unit; a flow path switching unit for switching a flow path of the additional gas from the additional gas supply line between the first and the second additional gas branch line; and a control unit configured to supply, before processing the substrate to be processed, the processing gas from the processing gas supply unit while performing a pressure ratio control on the branch flow control unit such that a pressure ratio between the inner pressures of the first and the second processing gas branch line is kept at a target pressure ratio, and then supply the additional gas from the additional gas supply unit after the inner pressures of the first and the second processing gas branch line become stable to be at a first and a second stable inner pressure, wherein in case of supplying the additional gas to the second processing gas branch line via the second additional gas branch line, the additional gas is supplied from the additional gas supply unit after the control unit switches the pressure ratio control on the branch flow control unit to a first fixed pressure control that controls the branch flows such that the first stable inner pressure is maintained in the first processing gas branch line, wherein in case of supplying the additional gas to the first processing gas branch line via the first additional gas branch line, the additional gas is supplied from the additional gas supply unit after the control unit switches the pressure ratio control on the branch flow control unit to a second fixed pressure control that controls the branch flows such that the second stable inner pressure is maintained in the second processing gas branch line, wherein, when the inner pressures of the first and the second processing gas branch line become stable to be at a third and a fourth stable inner pressure after supplying the additional gas, the control unit is configured to set a pressure ratio between the third and the fourth stable inner pressure as a second target pressure ratio different from the target pressure ratio, and switch the first or the second fixed pressure control on the branch flow control unit to another pressure ratio control that controls the branch flows such that a pressure ratio between the inner pressures of the first and the second processing gas branch line is kept at the second target pressure ratio.