| Summary: | 碩士 === 國立清華大學 === 工程與系統科學系 === 103 === Nowadays, in the semiconductor manufacturing process, the stability of plasma processing influence greatly to yield rate, while the plasma density is the key parameters for plasma processing. Therefore, monitoring and maintaining the plasma, by adjusting procedure parameter to achieve its needed state, it the important step to the process.
In this study, plasma absorption probe (PAP) is used to analyze that RF sheath affect the peak of spectrum in experiment. The probe tip is fed into the microwave, when the microwave resonates both with probe structure and with electron in the plasma, the microwave is absorbed greatly by plasma, in this time the microwave have lowest reflected and the absorption frequency can be obtained at the lowest point of the active plasma resonance spectrum (APRS). Using the High Frequency Structure Simulator (HFSS) to set the real plasma environment and probe structure, simulating and obtaining the active plasma resonance spectrum in simulation. Compare with the FWHM of spectrums in experiment,
The peak of spectrum in experiment is more broaden then in simulation, it will reduce the identification of absorption frequency, the slight changes of plasma density will be difficult to detect. The rf sheath effect can be support the phenomenon. In the experiment, using the RF-bias power to increase the plasma potential and finding the peak of spectrum is wider with the rf-bias power increasing, it is also confirm the rf sheath affect the plasma measurement. Developing new structure of plasma absorption probe by coating the dielectric on metal antenna to improve the bandwidth of resonance peak. According to the simulation result, the plasma absorption probe is not suitable for measurement in the high pressure and low-density plasma environment. Finally, the hairpin probe, which is the quarter-wavelength structure of resonant itself, be developed by simulation and experiment and the probe can measure the high pressure (~1 atm) and low plasma density (~2x109 cm-3). It is effective to measure environment the ALD and PECVD process.
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