Comparison of electron density measurements by using a plasma absorption probe and a double Langmuir probe in inductively coupled plasmas

Summary form only given, as follows. The absolute, spatially resolved electron densities in inductively coupled plasmas have been measured by using two different plasma diagnostic tools, a plasma absorption probe and double Langmuir probe. The plasma absorption probe is able to measure the absolute, spatially resolved electron density even when the probe is soiled with processing plasmas. The technique is based on the resonant absorption of surface waves excited in a cavity at the probe head. The plasma absorption probe consists of a small antenna connected with a coaxial cable. The antenna is enclosed in a tube inserted in a plasma. The plasma source is a planar inductively coupled plasma. Over a wide parameter range (gas type, input power and gas pressure), the results by the two techniques are compared and analyzed.