Process chamber for a supercritical process and apparatus for treating substrates having the same

Disclosed are a supercritical process chamber and an apparatus having the same. The process chamber includes a body frame having a protrusion protruding in an upward vertical direction from a first surface of the body frame and a recess defined by the protrusion and the first surface of the body frame; a cover frame; a buffer chamber arranged between the body frame and the cover frame; and a connector. The buffer chamber includes an inner vessel detachably coupled to the body frame providing a chamber space in the recess and an inner cover detachably coupled to the cover frame. The inner cover is in contact with a first surface of the inner vessel enclosing the chamber space from surroundings. The connector couples the body frame and the cover frame having the buffer chamber arranged therebetween such that the enclosed chamber space is transformed into a process space in which the supercritical process is performed.