| 摘要 |
PROBLEM TO BE SOLVED: To provide a method that is simple, but can prevent excess cleaning in order to minimize damages to the inside of a treatment chamber and jigs set inside. SOLUTION: When a cleaning gas (ClF3 gas) is fed into outer/inner tubes forming a treatment chamber of a vertical low-pressure CVD system in order to remove internal depositions, a temperature 15a of the downstream side (top region) of the ClF3 gas is set higher than a temperature 17a of the upstream side (bottom region) for etching. Subsequently, at a point (point g) when the inside temperature of the central part (center region) rises due to the reaction of the ClF3 gas and depositions, the relation of temperatures at the bottom region and the top region is made reversed for etching. When the inside temperature of each region reached the corresponding predetermined temperature (points h, I and j), the ClF3 gas is stopped. Etching uniformity is improved by temporal change of the temperature, so that excess etching can be avoided by monitoring the internal temperature.
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