Langmuir Probe Perturbation in Inductively Coupled Plasmas

다국어 초록 (Multilingual Abstract)

For radial plasma density profile measurements, Langmuir probes are usually used. In this paper,
a Langmuir probe was located at 4 cm below a dielectric window and the measurement was
performed at 25 mTorr of argon at various rf powers (13.56 MHz). We found that the radial plasma
density distributions became asymmetric as the rf power increases. To investigate the cause of this
asymmetric density distribution, we installed a floating probe that can measure plasma densities
and the electron temperatures in real time on the chamber wall. At high rf powers, as the probe
body went in, the plasma density measured by the floating probe decreased. This indicates that
the entire plasma density is affected by the probe intrusion. It appears that the Langmuir probe
passes through the skin layer and the probe body impedes the electron heating process in the skin
layer. As a solution, a probe body shape to avoid this perturbation is presented.

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