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.

This research involved an experimental investigation of the relationship between the plasma parameters and etching properties of SiO 2 over poly-Si mask in Ar/C 4 F 8 capacitively coupled plasma (CCP). In these experiments, the etching process was conducted in CCP and the external conditions such as the applied power, pressure, and gas ratio were varied. In addition, the density of radicals, which dominantly participate in surface reactions, the electron density, and the self-bias voltage were measured. As a result, deposition of the CF x polymer film on the poly-Si mask lowered the electron density and self-bias voltage and the etch rate of the target and the mask increased as the internal parameters of the plasma increased. This result indicated that the electron density and the self-bias voltage, which represent the physical etch elements of ion flux and energy, respectively, have a marked influence on the etching process. Consequently, our work led us to propose a critical value, which is the product of the electron density and self-bias voltage, n e V bias , to analyze the etching mechanism. Our results are also expected to serve as a basic processing database that enables an in-depth understanding of etching.

Recently, fluorocarbon (FC) film deposition on a SiO2 surface has become one of the most important processes in semiconductor manufacturing because the formation of a passivation layer on SiO2 during the deposition process plays a crucial role in atomic layer etching and high aspect ratio contact (HARC) etching, areas that are attracting intense interest in the semiconductor industry. In this work, various trends of sample thickness change, namely, decreasing, increasing, and anomalously increasing trends with time, were observed during FC film deposition on a SiO2 surface. The total thickness including both SiO2 and FC film was found to change during the deposition process in various ways depending on the plasma conditions. This can be successfully explained by considering the mechanism of SiO2 etching with FC plasma, taking into account the dependence of the SiO2 etch rate on FC film thickness. This result is expected to be utilized in semiconductor processes such as HARC etching where a precise control of film thickness is needed.

SiO2 etching characteristics were investigated in detail. Patterned SiO2 was etched using radio-frequency capacitively coupled plasma with pulse modulation in a mixture of argon and fluorocarbon gases. Through plasma diagnostic techniques, plasma parameters (radical and electron density, self-bias voltage) were also measured. In this work, we identified an etching process window, where the etching depth is a function of the radical flux. Then, pulse-off time was varied in the two extreme cases: the lowest and the highest radical fluxes. It was observed that increasing pulse-off time resulted in an enhanced etching depth and the reduced etching depth respectively. This opposing trend was attributed to increasing neutral to ion flux ratio by extending pulse-off time within different etching regimes.

One of the cleaning processes in semiconductor fabrication is the ashing process using oxygen plasma, which has been normally used N2 gas as additive gas to increase the ashing rate, and it is known that the ashing rate is strongly related to the concentration of oxygen radicals measured OES. However, by performing a comprehensive experiment of the O2 plasma ashing process in various N2/O2 mixing ratios and RF powers, our investigation revealed that the tendency of the density measured using only OES did not exactly match the ashing rate. This problematic issue can be solved by considering the plasma parameter, such as electron density. This study can suggest a method inferring the exact maximum condition of the ashing rate based on the plasma diagnostics such as OES, Langmuir probe, and cutoff probe, which might be useful for the next-generation plasma process.