| AVS 60th International Symposium and Exhibition | |
| Plasma Science and Technology | Tuesday Sessions |
| Session PS1-TuA |
| Session: | Plasma Diagnostics, Sensors and Control |
| Presenter: | T. Tsutsumi, Nagoya University, Japan |
| Authors: | T. Tsutsumi, Nagoya University, Japan T. Ohta, Meijo University, Japan K. Ishikawa, Nagoya University, Japan K. Takeda, Nagoya University, Japan H. Kondo, Nagoya University, Japan M. Sekine, Nagoya University, Japan M. Hori, Nagoya University, Japan M. Ito, Meijo University, Japan |
| Correspondent: | Click to Email |
High-precision, rapid temperature measurements on wafers such as silicon, sapphire, etc. are required for plasma processing. A method is demonstrated here that uses a frequency-domain low-coherence interferometer (FD-LCI).
In order to realize the plasma processing with high precision, the temperature control of wafer or chamber-wall is one of important factors. Especially the wafer temperature influences on etched profile and etching rates. Moreover, a spatial distribution of radicals in gas phase or plasma-surface interactions on the surface are affected by temperatures of the chambar-wall. Therefore, the precisely non-contact temperature-measurement technology is needed for the fabrication of electric devices.
In this study, we have developed a highly precise and non-contact temperature monitor using a Fourier domain low-coherence interferometer (FD-LCI) and a super luminescent diode (SLD: center wavelength: 1330 nm, spectral width: 37.6 nm) as a low coherence light source. The FD-LCI can measure an optical path length of wafer on the basis of auto-correlation signals, which are generated by interferences between the light reflected from the front and back surfaces, and analyzed by the inverse Fourier transform of spectral interferogram. Since the optical path is changed by thermal expansion and refractive-index, the wafer-temperatures can be analyzed. By this method, we have successfully achieved to estimate a temperature of various commercial wafers such as silicon, sapphire during plasma processes.