Reactive ion etching characteristics of partially-cured benzocyclobutene

This paper reports the reactive ion etching (RIE) characteristics of partially-cured benzocyclobutene (BCB) in sulrur-hexafluoride/oxygen (S F₆/O₂) plasmas. The etching rate and etch anisotropy are mainly dependent on RF power, chamber pressure, and SF₆ concentration. The processing parameters are investigated ranging from 50 to 200W, 22.5 to 270 mTorr, and 0% to 80%, respectively. According to the experiments, the BCB etching rate increases with RF power and chamber pressure, but decreases when the SF₆ concentration increases. We can achieve anisotropic etching using large RF power, high chamber pressure and high SF₆ concentration. Grass-like residue happens at low pressures, large power and low SF₆ concentration conditions. We also investigate the etching mechanisms of the dependence of the etching characteristics on the processing parameters.