| 摘要 |
PROBLEM TO BE SOLVED: To improve plasma treatment speed by forming, at some gas inlet ports of an upper electrode, portions the port diameter of which is increased in the direction toward the open ends of those gas inlet ports, and letting in gas through the portions. SOLUTION: Two types of gas inlet ports are formed, and the gas inlets ports 5a and 5b are alternately placed. The diameter of the gas inlet ports 5a is increased at their open ends, and the diameter of the gas inlet ports 5b is constant in the direction toward their open ends. The gas inlet ports 5a and 5b let in different types of gases from two respective system of gas piping. More specifically, a gas which is low in dissociation efficiency in plasma is let in through the gas inlet ports 5a and a gas high in dissociation efficiency in plasma is let in through the gas inlet ports 5b. As a result, a high-density plasma region 13 is produced in the upper region without concentrating on an upper electrode and the gas dissociation efficiency and the plasma processing speed are improved.
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