Nitride film forming method, semiconductor device fabrication method, capacitor fabrication method and nitride film forming apparatus

摘要

The nitride film forming method comprises the first step of loading a semiconductor substrate 12 into a reaction furnace, and decompressing the inside of the reaction furnace 14 to remove oxygen and water from the inside of the reaction furnace 14 and the semiconductor substrate 12, the second step of heating the reaction furnace 14 to further remove the oxygen and the water from the reaction furnace 14 and the semiconductor substrate 12, and the third step of purifying nitrogen gas to have the oxygen concentration to be 1 ppb or below, and performing thermal processing with the purified nitrogen gas being fed into the reaction furnace to form a nitride film 56 over the semiconductor substrate 12. The thermal nitriding is performed using an ultrahigh-purity nitrogen gas of an oxygen concentration of 1 ppb or below, whereby nitrogen film of very good quality can be formed without setting the thermal processing temperature very high.