Simulation of silicon etching in NF₃ plasma reactor

Abstract

The plasma etching process plays a vital role in microelectronics chip manufacturing and cleaning of the vapour deposition reactors. Plasma etching phenomena can be better understood using plasma-chemistry models. Plasma discharge generates various gas species and gas species interact with the surface species. The interaction of gas species and surfaces species creates volatile species which can come out from the surface very easily and contributes to the surface etch. The simulation of the etching process makes the plasma etching reactor superior by enhancing the performance and exploration of processes. The simulation of the silicon etching is carried out in an NF₃ plasma reactor. The plasma chemistry along with the surface chemistry models are utilised for reaction happening inside the reactor. Reactor parameters, such as pressure, RF power deposition, mass flow rate, etc. were varied to enhance the reactor performance and understand the events’ dependency. The simulation was done using the Perrin experimental parameters and simulated results were compared with the published experimental results. The simulation is based on the mixed plasma reactor within a certain volume. It does not account for geometrical parameters and therefore it is 0-d modelling of the reactor. The simulation is based on the flow dynamics along with gas and surface chemistry. The simulation shows the same trend as the experiment. The established simulation model was also used to estimate the etch rate in future in-house experiments. The parameters and simulation results of a future in-house experiment are also included in the report. The work conducted here is to support future in-house experiments of silicon etching for better performance. This is also important for establishing an etching facility for manufacturing electronic integrated circuit and metal surface cleaning.