Substrate processing apparatus and substrate processing method

A substrate processing method comprising:

• holding a first area of a lower surface of a substrate with a centering stage;
• obtaining an amount of eccentricity and an eccentricity direction of a center of the substrate, when held on the centering stage, from a central axis of the centering stage;
• performing a centering operation for aligning the center of the substrate with a central axis of a process stage, based on the amount of eccentricity and the eccentricity direction of the center of the substrate, held on the centering stage, from the central axis of the centering stage, the process stage including an increased diameter portion having an annular substrate holding surface forming a lip portion for holding a second area of the lower surface of the substrate, a decreased diameter portion supporting the increased diameter portion, and the increased diameter portion having an outer diameter larger than an outer diameter of the decreased diameter portion;
• transferring the substrate from the centering stage to the process stage to be held on the process stage;
• obtaining an amount of eccentricity and an eccentricity direction of the center of the substrate, held on the process stage, from the central axis of the process stage;
• confirming that the obtained amount of eccentricity of the center of the substrate from the central axis of the process stage is within a predetermined allowable range;
• and
• processing the substrate while rotating the processing stage about the central axis of the processing stage, when the obtained amount of eccentricity of the center of the substrate from the central axis of the process stage is within the predetermined allowable range.

A substrate processing apparatus, comprising:

• a centering stage configured to hold a first area of a lower surface of a substrate;
• a process stage configured to hold a second area of the lower surface of the substrate;
• a process-stage rotating mechanism configured to rotate the process stage about a central axis of the process stage;
• an eccentricity detecting mechanism configured to obtain an amount of eccentricity and an eccentricity direction of a center of the substrate, when held on the centering stage, from a central axis of the centering stage;
• and
• an aligner configured to perform a centering operation for aligning the center of the substrate with the central axis of the process stage based on the amount of eccentricity and the eccentricity direction of the center of the substrate, held on the centering stage, from the central axis of the centering stage,
• wherein the process stage includes an increased diameter portion having an annular substrate holding surface for holding the second area, and a decreased diameter portion supporting the increased diameter portion,
• wherein the aligner obtains, after the substrate is transferred from the centering stage to the process stage and held on the process stage, an amount of eccentricity and an eccentricity direction of the center of the substrate, held on the process stage, from the central axis of the process stage by use of the eccentricity detecting mechanism;
• and
• confirms that the obtained amount of eccentricity of the center of the substrate from the central axis of the process stage is within a predetermined allowable range,
• wherein an upper surface of the increased diameter portion constitutes the annular substrate holding surface, and the annular substrate holding surface has an outer diameter smaller than a diameter of the substrate, and
• wherein an outer diameter of the increased diameter portion is gradually decreased from the upper surface which is the substrate holding surface, toward a lower surface of the increased diameter portion, and an outer diameter of the lower surface of the increased diameter portion is equal to an outer diameter of an upper surface of the decreased diameter portion.