Device and exception handling method for single-wafer wet process

This disclosure is directed to an exception handling method for a single-wafer wet process having the following steps: providing a wafer, an arm and a light receiver, the arm is connected to an actuating motor and provided with a nozzle and a light deflector, the actuating motor can rotate among multiple angular positions to swing the arm horizontally, the actuating motor is configured within an angular reference range when the nozzle is located at a center of the wafer, and the light deflector is located at a trigger position; projecting a ray from a predetermined position to the trigger position; swinging the arm and receiving the ray by the light receiver when the light deflector passes the trigger position; shutting the nozzle and rinsing the wafer if the light receiver detects the ray when the actuating motor is configured out of the angular reference range.