Although pulse-modulated plasma has overcome various problems encountered during the development of the high aspect ratio contact hole etching process, there is still a lack of understanding in terms of precisely how the pulse-modulated plasma solves the issues. In this research, to gain insight into previously observed phenomena, SiO2 etching characteristics were investigated under various pulsed plasma conditions and analyzed through plasma diagnostics. Specifically, the disappearance of micro-trenching from the use of pulse-modulated plasma is analyzed via self-bias, and the phenomenon that as power off-time increases, the sidewall angle increases is interpreted via radical species density and self-bias. Further, the change from etching to deposition with decreased peak power during processing is understood via self-bias and electron density. It is expected that this research will provide an informative window for the optimization of SiO2 etching and for basic processing databases including plasma diagnosis for advanced plasma processing simulators.

Arcing is a ubiquitous phenomenon and a crucial issue in high-voltage applied systems, especially low-temperature plasma (LTP) engineering. Although arcing in LTPs has attracted interest due to the severe damage it can cause, its underlying mechanism has yet to be fully understood. To elucidate the arcing mechanism, this study investigated various signals conventionally used to analyze arcing such as light emission, arcing current and voltage, and background plasma potential. As a result, we found that light emission occurs as early as 0.56 μs before arcing current initiation, which is a significant indicator of the explosive development of arcing as well as other signals. We introduce an arcing inducing probe (AIP) designed to localize arcing on the tip edge along with multiple snapshot analysis since arcing occurs randomly in space and time. Analysis reveals that the prior light emission consists of sheath and tip glows from the whole AIP sheath and the AIP tip edge, respectively. Formation mechanisms of these emissions based on multiple snapshot image analysis are discussed. This light emission before arcing current initiation provides a significant clue to understanding the arcing formation mechanism and represents a new indicator for forecasting arcing in LTPs.

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The microwave planar cutoff probe, recently proposed by Kim et al. is designed to measure the cutoff frequency in a transmission (S21) spectrum. For real-time electron density measurement in plasma processing, three different types have been demonstrated: point-type, ring-type (RCP), and bar-type (BCP) planar cutoff probes. While Yeom et al. has shown that the RCP and BCP are more suitable than the point-type probe for process monitoring, the basic characteristics of the ring- and bar-type probes have yet to be investigated. The current work includes a computational characterization of a RCP and BCP with various geometrical parameters, as well as a plasma parameter, through a commercial three-dimensional electromagnetic simulation. The parameters of interest include antenna size, antenna distance, dielectric thickness of the transmission line, and input electron density. Simulation results showed that the RCP has several resonance frequencies originating from standing-wave resonance in the S21 spectrum that the BCP does not. Moreover, the S21 signal level increased with antenna size and dielectric thickness but decreased with antenna distance. Among the investigated parameters, antenna distance was found to be the most important parameter to improve the accuracy of both RCP and BCP.