SEMICONDUCTOR MANUFACTURING EQUIPMENT

PROBLEM TO BE SOLVED: To provide a method and a mechanism for stably maintaining and automatically controlling the quantity of air to be mixed into a quartz tube. SOLUTION: In semiconductor manufacturing equipment wherein oxygen or a steam gas produced by the reaction of oxygen and hydrogen is introduced, and a semiconductor substrate is heated up to a prescribed temperature under prescribed exhaust pressure and then is heat-treated to form an insulation film, or in semiconductor manufacturing equipment wherein nitrogen or a mixed gas of nitrogen and oxygen is introduced, and a semiconductor substrate is heated up to a prescribed temperature under prescribed exhaust pressure and then is heat-treated to diffuse impurities in the semiconductor substrate, treated gas is exhausted by the exhaust pressure being automatically controlled by means of a variable valve provided in an exhaust pipe to reduce variations in the thickness of an oxide film grown on the semiconductor substrate. COPYRIGHT: (C)2003,JPO