Optical Computer Aided Tomography of an Inductively Coupled Discharge
Eric C. Benck, J R. Roberts
Optical computer aided tomography (CAT) is being investigated as a potential in situ diagnostic for measuring plasma uniformity without making assumptions concerning the plasma symmetry. The presence of an opaque vacuum chamber wall severely limits the different directions optical emission measurements can be made of the plasma. The tomographic inversion problem with restricted optical access is being solved using Tikhonov regularization. The accuracy of the inversion process is investigated for several different observation geometries using theoretical test data generated from known distributions. Optical CAT is applied to an ICP-GEC plasma source, with all the measurements made through a single large 152 mm diameter window. Axially asymmetric plasma distributions are demonstrated as a function of gas flowrate and gas composition.
March 23-27, 1998
International Conference on Characterization and Metrology for ULSI Technology
and Roberts, J.
Optical Computer Aided Tomography of an Inductively Coupled Discharge, International Conference on Characterization and Metrology for ULSI Technology
(Accessed December 2, 2023)