PURPOSE: To prevent the formation and deposition of ammonium nitrate by controlling the temperature of a substrate for avoiding the deposition of ammonium nitrate and peeling and removing a resist by the action of ultraviolet ray, ozone containing ammonia and heat higher than a particular value.

CONSTITUTION: A plurality of nozzles 10 are welded and fixed to a highly pure quartz plate 11, said nozzles 10 are welded and connected to a quartz branch cylinder 9, and the branch cylinder 9 is arranged near a light source 15 inside a containers 16 of an ultraviolet ray source 15. A mixed steam gas containing ozone and ammonia is supplied to the branch cylinder 9 by a connecting tube 8 and also blown to the surface of wafer 12 by the nozzles 10. Here, ammonium nitrate is formed at the same time with resist removing reaction. Ammonium nitrate is decomposed at about 210°C. Thus, the deposition of ammonium nitrate can be prevented by resist removing treatment at the temperature higher than 210°C by controlling a heater built-in a stage 13.