Study on the characteristics of inductively coupled plasma using multidipole magnets and its application to oxide etching

In this study, the effects of multidipole type of magnets on the characteristics of the inductively coupled plasmas and SiO₂ etch properties were investigated. As the magnets, four pairs of permanent magnets were applied and C₂F₆, CHF₃, C₄F₈, H₂, and their mixtures were used to etch SiO₂. When SiO₂ was etched using the fluorocarbon gases, the significant increase of SiO₂ etch rate and also the increase of etch uniformity could be obtained by applying the magnets. By optimizing the process parameters at 1000 W of inductive power with the magnets, the highest SiO₂ etch rate of 800 nm/min with the SiO₂: photoresist etch selectivity about 4 could be obtained for C₄F₈ and the highest etch selectivity more than 15 with the SiO₂ etch rate of 400 nm/min could be obtained for C₄F₈/50% H₂.