Method of forming a deep trench in a substrate

摘要

Methods of forming deep trenches in substrates are described. A method includes providing a substrate with a patterned film disposed thereon, the patterned film including a trench having a first width and a pair of sidewalls, the trench exposing the top surface of the substrate. The method also includes forming a material layer over the patterned film and conformal with the trench. The method also includes etching the material layer to form sidewall spacers along the pair of sidewalls of the trench, the sidewall spacers reducing the first width of the trench to a second width. The method also includes etching the substrate to form a deep trench in the substrate, the deep trench undercutting at least a portion of the sidewall spacers.