摘要 |
The present invention aims to decrease reflected waves in a vacuum chamber to suppress standing waves, thereby easily controlling a plasma density so that uniform treatment can be performed. An electromagnetic wave absorber 6 composed of a resistor such as carbon, a dielectric having a large dielectric loss, such as water, or a magnetic material such as ferrite-based ceramic, or a combination of these, is provided on an inner wall surface of a first vacuum chamber 21. Microwaves introduced from a waveguide 25 into the first vacuum chamber 21 via a transmissive window 23 are absorbed to the electromagnetic wave absorber 6 to suppress reflected waves, whereby a plasma density distribution with a nearly planned pattern is easily formed at an ECR point.
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