Patent ID: 7575636

Claim:
A substrate processing apparatus, comprising: a substrate holding device for holding a substrate in a horizontal position, said substrate holding device being operable to lower the substrate into a processing liquid and to hold the substrate within the processing liquid in a bubble removal position and a substrate processing position; and a processing tank for holding the processing liquid, said processing tank including: a gas bubble removing section including a circular wall having a circular top end portion with an outer diameter smaller than an outer diameter of the substrate to be held by said substrate holding device; and a processing liquid supply inlet for supplying the processing liquid into said processing tank such that the processing liquid must flow through a center area surrounded by said circular wall toward a lower surface of the substrate to be held by said substrate holding device and then radially along the lower surface of the substrate toward a periphery of the substrate; wherein said substrate holding device and said gas bubble removing section are arranged such that, when the substrate is lowered into the processing liquid in said processing tank to the bubble removal position which is lower than the substrate processing position, a circular slit is formed between said circular top end portion of said circular wall and a periphery of the lower surface of the substrate to thereby increase a flow speed of the processing liquid flowing radially along the lower surface of the substrate through the circular slit so as to remove gas bubbles resting against the lower surface of the substrate; and wherein said substrate holding device and said gas bubble removing section are arranged such that, when the substrate is raised to the substrate processing position within the processing liquid from the bubble removal position, a sufficiently wide clearance is formed between said circular top end portion of said circular wall and the periphery of the lower surface of the substrate to thereby form a stable flow of the processing solution.