Substrate processing apparatus

Abstract

A technique is provided that can easily achieve correction of stage position based on refractive index distribution. A substrate processing apparatus includes: a stage 10 for holding a substrate W; a position measuring unit 60 that irradiates the stage 10 with laser light 611 and measures the position of the stage 10 based on the detection result of the laser light 611 reflected from the stage 10; an imaging unit 70 that captures a background image 33 with a predetermined pattern via the laser light 611; and a position calculation unit 94 that calculates the position of the stage 10 based on the measurement result of the position measuring unit 60. The position calculation unit 94 calculates the refractive index distribution from the image obtained by the imaging unit 70 and corrects the measurement result of the position measuring unit 60 based on the calculated refractive index distribution.

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