Apparatus for and method of processing substrate

Abstract

A substrate processing apparatus includes optical sensors (46) and a controller (30). The optical sensors (46) emit and receive inspection light in detection positions (P1, P2) on an advancing/retracting path of a substrate (W), and output a light blocking signal when the amount of inspection light received is lower than a threshold value. The controller (30) detects the position of an edge (E) of the substrate (W), based on a falling edge of the light blocking signal, when the substrate (W) moves away from the detection position (P1). The controller (30) detects the position of the edge (E) of the substrate (W), based on a rising edge of the light blocking signal, when the substrate (W) moves toward the detection position (P2). Thus, the position of the edge (E) of the substrate (W) is detected based on the signal of a portion closest to the outside of the substrate (W) among light blocking signals outputted near the edge (E) of the substrate (W). This allows the position of the edge (E) of the substrate (W) to be detected appropriately.

Dependencies are inferred from the claim text.