Study of Profile Improvement Through Shift of Phase Between RF Source and Bias at the RF-Biased ICP Reactor

This study explores a novel approach to improving the etching process by controlling the phase shift between the RF source and RF bias in a 13.56 MHz RF-biased Inductively Coupled Plasma (ICP) reactor. By adjusting the phase difference, we aim to optimize plasma density and ion energy, leading to enhanced control over the etch rate and pattern profile, while minimizing sidewall damage.

Our experimental results show that the phase shift significantly influences the plasma characteristics, including ion flux, plasma impedance, and reactance. These changes result in variations in etch rate, with the most favorable etching profiles observed at a specific phase shift (240°), where plasma density is optimized, and sidewall damage is minimized. Optical emission spectroscopy (OES) and scanning electron microscopy (SEM) analyses confirm the relationship between phase shifts and the resulting etching profiles, providing valuable insights into the interaction between plasma characteristics and etch quality.

The findings of this research highlight the potential of phase shift control as an efficient method for enhancing precision in semiconductor etching processes, offering new pathways for process optimization in advanced semiconductor manufacturing.