Effect of Susceptor Temperature on Ion Energy and Angle Distributions in a Cap Acitively Coupled Plasma

Abstract

In semiconductor fabrication, the temperature of a susceptor is adjusted to control deposition rate and quality of a thin film in plasma-enhanced chemical vapor deposition (PECVD) process. Kim and Lee reported that thermal diffusion due to a heated susceptor affects the distribution of neutrals and radicals [1]. Unintentionally, the high temperature on the susceptor causes depletion of background gas, which can affect ion energy and angle distribution (IEAD) due to the reduced collisions of ions with neutrals. In an atomic layer etching (ALE) process, it is important to control ion energy and angle distributions. The ion energy must be in ALE window for self-limiting reaction, and the ion incident angle should be perpendicular to the substrate for anisotropic etching [2], [3]. In this study, we investigate the effects of susceptor temperature on plasma parameters, especially IEAD, in a capacitively coupled plasma (CCP) using particle-in-cell/Monte Carlo collision method. With the increase of susceptor temperature, background gas density near the wafer is depleted, the plasma density decreases, and the sheath size increases, respectively. Finally, ion energy increases, and the angle distribution becomes narrower due to fewer collisions.