Production of a structure in a substrate comprises forming a hard mask on the substrate, forming a structure of trenches in the substrate

摘要

Production of a structure in a substrate (10) comprises forming a hard mask (20) on the substrate; forming a structure of trenches (T1, T2) in the substrate having a high aspect ratio using the mask; self-adjusting a second hard mask (30) on the first hard mask and the trench structure using non-conforming deposition of a Ti or Ti compound so that the deposited material of the second mask is deposited only on the upper side of the first mask; converting the Ti or Ti compound by tempering into TiO2; and forming a modified structure by selectively etching using the second mask so that the modified structure has even higher aspect ratio. Preferred Features: The first and/or second masks are deposited by a CVD process.