Hardware design and process optimization of industrial ICP N2 reactor using Two and Three Dimensional CFD models

The current report presents a systematic study on the hardware design and process optimization of industrial ICP reactor using comprehensive CFD modeling. As a first step, the 2D axisymmetric model is developed to simulate nitrogen discharge in Eugenus's ICP reactor. RF system is composed of RF generator, matching network, current ratio splitting system, and ICP plasma discharging antenna. Antenna design consists of inner and outer coil antennas which inductively shape magnetic field and corresponding E-field at target locations. It was observed that impedance of both antennas was relatively near series resonance location which is low resistance/maximum current state. Commercial modeling software, CFD-ACE+ was used for simulations of inductively coupled plasma reactor (without wafer bias) to address gas flow, heat transfer, plasma chemistry and electromagnetics in a coupled fashion. The parametric investigations have been performed with different coil current ratio, chamber pressure and mass flow rate to optimize the process. The plasma uniformity at 1mm above wafer was calculated for all the cases and results show that when current ratio and mass flow rate are fixed, higher processing pressure will obtain better uniformity. In addition, mass flow rate has little influence on the plasma uniformity. In a reasonable range, higher current in the outer trirosa antenna and lower current in durosa antenna can help achieve better plasma uniformity. A full three dimensional model also has been developed, and further studies are being performed including different coil current ratio. For three dimensional model, a 49-point uniformity calculation method is used and same trend was found compared with two dimensional simulation. The numerical results have been presented with plasma and species densities, electromagnetic field, ion flux to the substrate, and ion energy and angular distributions. Limited experiments are performed and presented to validate the CFD model.