Evaluation of an advanced dual hard mask stack for high resolution pattern transfer

A dual hard mask concept for high resolution patterning has been evaluated with focus on highly selective etching processes for semiconductor manufacturing. The integration of thin SiO2 and ZrO2 hard mask materials enables highly selective patterning via plasma etch processes for future technology nodes. The patterning sequence is demonstrated for hole arrays with sizes down to 25 nm using a 50 nm thin resist which leads to the fabrication of trenches in silicon with aspect ratios up to 20:1. Alternative ZrO2 based materials were investigated with focus on surface roughness reduction since it influences the final line etch roughness. Here Si-doped ZrO2 (ALD) and spin-coatable ZrO2 were compared to the pure and crystalline ZrO2 as main selective material.