Abstract: A multi-scale numerical method coupled with the reactor, sheath and trench model is constructed to simulate dry etching of SiO₂ in inductively coupled C₄F₈ plasmas. Firstly, ion and neutral particle densities in the reactor are decided using the CFD-ACE+ commercial software. Then, the ion energy and angular distributions (IEDs and IADs) are obtained in the sheath model with the sheath boundary conditions provided with CFD-ACE+. Finally, the trench profile evolution is simulated in the trench model. What we principally focus on is the effects of the discharge parameters on the etching results. It is found that the discharge parameters, including discharge pressure, radio-frequency (rf) power, gas mixture ratios, bias voltage and frequency, have synergistic effects on IEDs and IADs on the etched material surface, thus further affecting the trench profiles evolution.