Non‐self‐sustained electron beam RF‐generated plasma in application for functional surface pretreatment

Simulation of non‐self‐sustained plasma generated by a 2‐keV electron beam in Ar with radiofrequency (RF) biasing is carried out using a one‐dimensional particle‐in‐cell Monte Carlo method. The effect of 10–30 mTorr gas pressure and different RF voltages of 0–45 V on the ion energy and angle distribution functions is analyzed and discussed. The performed ab initio dynamic simulations confirmed the possibility to eliminate methyl groups from the low‐k surfaces with low‐energy (10–20 eV) Ar ions, thereby turning these surfaces from hydrophobic into hydrophilic. The analytical model is developed to calculate the ion fluxes on two‐dimensional trench walls and bottom for conditions under study. It was shown that plasma with a pressure of 10 mTorr and a bias voltage of ≤45 V is better suited for pretreatment of the low‐k trench walls. The combination of low‐k surface pretreatments and area‐selective deposition of self‐assembled monolayers on trench sidewalls seems to be a perspective approach for fabrication of metal barriers without the bulk damage of low‐k films. In this paper, we theoretically show that e‐beam‐sustained radiofrequency plasma with controlled energy and angular distributions of low‐energy ions may be one of the most promising methods for pretreatment of the low‐k trench walls.