Continuous Wave Etching Using Ar/Cl₂Inductively Coupled Plasmas

The semiconductor industry relies heavily on plasma etching, a process of removing materials from the surface of a substrate to create nano-scale patterns, essential in the manufacturing of microelectronics devices. Continuous-wave (CW) etching, in particular, involves the acceleration of positive ions towards a solid substrate where continuous bias power is applied. The Hybrid Plasma Equipment Model (HPEM) was used to computationally investigate CW etching of silicon wafers using Ar/Cl₂ inductively coupled plasmas (ICP). The ICP has a radio-frequency (RF) biased substrate similar to a commercial plasma etch tool. Feature evolution was simulated using the Monte Carlo Feature Profile Model (MCFPM). The cylindrically symmetric ICP chamber is 15.7 cm height and 27.3 cm radius, with a 30 cm diameter wafer. A mixture of 99% Argon and 1% Cl₂ gas is pumped into the chamber at 600 sccm to generate and sustain a bulk plasma using CW ICP power. Higher CW bias power results in improved etch properties and anisotropic features. Further research is to be performed to investigate feature profiles during pulsed bias power.