Plasma density information measuring method, probe used for measuring plasma density information, and plasma density information measuring apparatus
First Claim
1. A plasma density information measuring method, comprising the steps of:
- supplying high-frequency power to plasma;
measuring a physical amount indicative of reflection or absorption state of said high-frequency power by plasma load; and
obtaining a plasma absorption frequency which is a frequency in which strong absorption of high frequency power occurs attributed to the plasma density based on the result of measurement of the physical amount as above.
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Abstract
A plasma density information measuring method capable of easily measuring the plasma density information over the long term, a probe for measuring the plasma density information, and a plasma density information measuring apparatus are disclosed. A measuring probe is set such that a tip end of a glass tube of the measuring probe is brought into contact with plasma PM to be measured. High-frequency power sent through a coaxial cable is supplied to the plasma PM from a loop antenna through a wall of the tube, and reflection power of the high-frequency power is received by the loop antenna to obtain a counter frequency variation of reflection coefficient of the high-frequency power. In the obtained reflection coefficient, a portion thereof in which the reflection coefficient is largely reduced is a peak at which strong absorption of high-frequency power is caused due to the plasma density. The plasma density can be obtained from the plasma absorption frequency.
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Citations
7 Claims
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1. A plasma density information measuring method, comprising the steps of:
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supplying high-frequency power to plasma;
measuring a physical amount indicative of reflection or absorption state of said high-frequency power by plasma load; and
obtaining a plasma absorption frequency which is a frequency in which strong absorption of high frequency power occurs attributed to the plasma density based on the result of measurement of the physical amount as above. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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Specification