| 摘要 |
PURPOSE:To prevent the air which has infiltrated into the chamber from contacting with an object to be processed by providing a protective cap formed in a cylinder in a fork-shape. CONSTITUTION:In a process chamber 2, since a gas which was made lighter by heating moves to the upper space, heavy and low-temperature air infiltrate into the process chamber 2 from the furnace inlet 5 through the gap between a sealing cap 19 and the inner periphery of a process tube 1. However, since a wafer 8 is surrounded by a protective cap 10, the air which has infiltrated tends to flow from the furnace inlet 5 to a supply port 4, but it is pressed back by a process gas flowing in the opposite direction. At this time, since the protective cap 10 narrows the passage for the process gas and the air, a pressure difference occurs between the front and the back of a blockade wall portion 12 of the protective cap 10 in the inner space of the process chamber 2, so that pressing back of the air by the process gas effectively acts. |
