Process and apparatus for manufacturing MOS device

摘要

A process and apparatus for manufacturing MOS devices are disclosed. The process comprises the step of controlling a first clearance linear speeds (1st CLSs) X which is the flows of an oxidizing and an annealing gases defined as ratios of the flow rates thereof to the area of a clearance between a semiconductor wafer and the interior surface of the tube of a heat treating furnace to be at least 30 cm/min while the semiconductor wafer is oxidized and annealed. The process comprises the step of controlling a second clearance linear speed (2nd CLS) Y which is a flow of the annealing gas defined as a ratio of the flow rate thereof to the area of the clearance to be at least 100 cm/min while the semiconductor wafer is taken out of the tube. The process comprises the step of controlling a relation between the 1st CLSs X and the 2nd CLS Y so that Y>/=-2.5 X+275. The process and the apparatus reduce and control the fixed-charge density in the oxide film of a MOS device with a high repeatability.