The Plasma Etching of the Deep Hole Structure in Silicon with the Mixed Gas of SF6, HBr and O2

We studied the inductively coupled plasma (ICP) etching of deep silicon hole with the etchant gas of $\mathrm{SF}_{6}/\mathrm{HBr}/\mathrm{O}_{2}$. We mainly researched the influence of HBr flow and bias voltage during the plasma etching process. Based on the profile of Si hole, we found that increasing the HBr flow could obviously enhance the etching rate within a proper range and the bias voltage could control the roughness of the sidewall. Through balancing the HBr flow and bias voltage, we could realize the vertical and smooth sidewall of the Si hole, which could be applied to other plasma etching of Si hole requiring high quality profile.