Plasma asymmetry effects induced by inter-electrode thermal gradients in capacitively coupled radio frequency plasmas

Abstract To enhance feature-scale etching and deposition control, precise temperature regulation of wafer electrodes is critical in semiconductor manufacturing. Thermal gradients between wafers and chamber walls induce non-uniform background gas distributions, significantly altering plasma characteristics. This study employs a coupled one-dimensional spatial and three-dimensional velocity resolution (1D3V) Direct Simulation Monte Carlo- particle-in-cell/Monte Carlo collision (PIC/MCC) numerical model to investigate the effects of different electrode temperatures on capacitively coupled plasmas under low-pressure conditions. Non-uniform gas distributions generate asymmetric discharge behavior and induce a DC self-bias that depends approximately linearly on the temperature difference between the powered and grounded electrode. Consequently, ion fluxes, ion energy distributions, and electron heating mechanisms exhibit significant modulation—a phenomenon that varies substantially with pressure.