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UV-VUV Absorption Spectroscopy for Radical Density Measurement in Processing Plasmas

2:40 pm - 3:10 pm

During plasma processes such as etching and deposition, the fundamental plasma parameters play the key role determining process yield and quality via controlling etching/depositing rate, uniformity, selectivity and anisotropy. Electron temperature and electron density are well known as fundamental plasma parameters which can be precisely determined by various diagnostic methods such as electrostatic probe. However, recently, radicals of small reactive atomic or molecular forms have been strongly attracted in processing plasmas because the most of plasma processes are influenced by chemical reactions between plasma and substrates. Especially, the measurement of radical density directly linked to etch or deposition rate is very important. Therefore, various non-invasive methods to measure radical density in the plasma have been studied. In this presentation, a spectroscopic method based on Beer-Lambert law calculating absorption intensity of external light is suggested to measure absolute density of atomic and molecular species generated in low-pressure inductively coupled plasmas. For the measurement of molecular species such as CF2, a broadband UV absorption spectroscopic methods is employed. Especially, in this work, a probe-type absorption spectroscopic system is suggested to investigate a spatial profile of CF2 density. On the other hand, a self-absorption VUV absorption spectroscopic method is evaluated to measure absolute density of atomic species such as hydrogen in the plasma. In this case, the effect of self-absorption by plasma lamp emitting VUV light is theoretically evaluated to improve the measurement precision. Based on UV and VUV absorption spectroscopic method, the absolute density of atoms and molecules for various plasma conditions are measured in low pressure plasmas and discussed the relation with plasma temperature and density. 

Speaker

SY Moon

Se Youn Moon

Associate Professor, Jeonbuk National University

Se Youn Moon, Ph.D. has been working for Department of Quantum System Engineering in Jeonbuk National University since 2012. From 2012, he is managing plasma experiments laboratory focusing plasma diagnostics and plasma surface applications.


Prior to joining Jeonbuk National University, Moon was senior researcher at University of Houston, senior researcher at LG Electronics and Samsung Electronics. During his 5 years at industries, Moon spent time to develop new PECVD for thin film solar cell in LG Electronics and new plasma etching processes in Samsung Electronics, respectively.


Moon received Ph.D degree in plasma physics from KAIST, Daejeon, Korea. In Asia-Pacific Plasma Surface Engineering Conference, Moon had been appointed as a young scientist. From 2001, Moon has been published 70 international journal papers related to plasma diagnostics and atmospheric pressure plasma technologies.