Spatio-temporal Kinetic Analysis of Anomalous Heating and Skin Depth Evolution in Inductively Coupled Plasmas under Varying Power and Pressure Conditions

Inductively Coupled Plasma (ICP) systems are widely used in advanced semiconductor fabrication for their ability to achieve high plasma density and low ion energy, enabling highly uniform etching and deposition in sub-3 nm technology nodes [1]. Electron heating in ICP is primarily driven by inductively generated electromagnetic fields, with the classical skin effect prominently observed at low pressures. However, anomalous heating, a non-classical energy absorption mechanism, can emerge under certain conditions, altering power deposition profiles and electron energy distributions [2]. Fluid-based models have offered insights into time-averaged fields, but their assumption of Maxwellian EEPFs limits the ability to resolve non-equilibrium and non-local electron behavior. Moreover, detailed analysis of skin depth dynamics and localized heating remains limited. In this study, we employ a two-dimensional Particle-in-Cell/Monte Carlo Collision (PIC/MCC) simulation to investigate how varying RF power and gas pressure affect skin depth evolution, spatial power localization, and EEPF distortion. Bulk and sheath-edge electron heating mechanisms are distinguished through phase-resolved power absorption analysis. Additionally, non-Maxwellian characteristics of the EEPF are quantitatively assessed to uncover kinetic effects in anomalous electron heating not captured by fluid models.