SUBSTRATE TREATING APPARATUS INCLUDING EXHAUST LINE FOR SENSING OXYGEN

Provided is a substrate treating apparatus including an exhaust line for sensing oxygen. The substrate treating apparatus includes a gas exhaust pipe which protrudes from a process chamber, a first monitor pipe, a monitor valve, and a second monitor pipe which are successively located from the gas exhaust pipe to the opposite side of the gas exhaust pipe in order to be connected to the gas exhaust pipe, a monitor sensor which is located in the second monitor pipe, a gas flow control network and the monitor valve which are located between the gas exhaust pipe and the monitor sensor, and a control part which is electrically connected to the gas flow network and the monitor sensor.