Control of Ion Energy and Angle Distribution via Waveform-Driven Embedded Electrode in Capacitively coupled plasma by using two-dimensional particle in cell simulation

As device miniaturization progresses, the development of next-generation DRAM and 3D NAND structures has highlighted the need for high aspect ratio (HAR) etching techniques. To achieve superior etch profiles, precise control of ion flux and ion energy–angle distribution (IEAD) is required; in particular, resolving plasma nonuniformity caused by electrical characteristics at the wafer edge and overall plasma density imbalances is essential. In this study, we investigate the effect of the embedded electrode in the focus ring of a CCP chamber on the plasma behavior near the wafer edge using a two-dimensional particle-in-cell (PIC) simulation parallelized using a GPU. The embedded electrode was placed inside the focus ring next to the bottom electrode. We apply single-frequency, sinusoidal dual-frequency, and pulsed dual-frequency RF waveforms with a high frequency of 40 MHz and a low frequency of 400 kHz. The surface charge density on the focus ring is controlled by each waveform, which in turn modifies local sheath oscillations. These changes allow active modulation of ion flux and IEAD. In addition, we propose a method to improve plasma density uniformity across the entire wafer beyond localized edge control by applying waveform-based driving techniques.