A process chamber is provided for an etching apparatus that etches a substrate, such as a liquid crystal display (LCD) substrate, using plasma. The process chamber may include a chamber body, in one wall of which a gate slit is formed, a rotary inner door that opens and closes an inner opening of the gate slit, and a door driving mechanism that rotates the inner door. When the substrate is etched, the inner door is closed preventing an interior of the chamber body from communicating with the gate slit. Thereby, a space in which the plasma is formed may be maintained symmetrical, so that the plasma may be uniformly distributed in an interior of the chamber body.