Refined Appearance Potential Mass Spectrometry for High Precision Radical Density Quantification in Plasma

Abstract

As the analysis of complicated reaction chemistry in bulk plasma has become more important, especially in plasma processing, quantifying radical density is now in focus. For this work, appearance potential mass spectrometry (APMS) is widely used; however, the original APMS can produce large errors depending on the fitting process, as the fitting range is not exactly defined. In this research, to reduce errors resulting from the fitting process of the original method, a new APMS approach that eliminates the fitting process is suggested. Comparing the neutral densities in He plasma between the conventional method and the new method, along with the real neutral density obtained using the ideal gas equation, confirmed that the proposed quantification approach can provide more accurate results. This research will contribute to improving the precision of plasma diagnosis and help elucidate the plasma etching process.

Determination of Plasma Potential Using an Emissive Probe with Floating Potential Method

“…In particular, plasma has played a significant role in plasma processes such as plasma etching [ 1 , 2 , 3 ], ashing [ 4 ], deposition [ 5 ], and plasma decomposition [ 6 , 7 ]. To analyze the process chemistry and mechanism, several instruments have been developed and utilized, such as voltage–current probes [ 8 , 9 ], optical emission spectroscopy [ 10 , 11 ], and quadrupole mass spectrometers [ 12 , 13 ]. Recently, understanding plasma behavior in plasma processing has attracted significant attention, since plasma produces chemical species and thus dominates process chemistry [ 14 ].…”