The present invention provides a semiconductor manufacturing apparatus having a slit valve control system including first and second process chambers disposed adjacent to each other, a slit aperture disposed between the first and second chambers, a slit valve to open and close the slit aperture between first and second chambers, an air source to operate the slit valve, a pressure supply flow path connecting the slit valve with the air source, and a pressure regulator installed on the supply flow path to regulate pressure supplied from the air source to the slit valve.