Multi-angled deposition and masking for custom spacer trim and selected spacer removal

摘要

Multi-angled deposition and masking techniques are provided to enable custom trimming and selective removal of spacers that are used for patterning features at sub-lithographic dimensions. For example, a method includes forming a sacrificial mandrel on a substrate, and forming first and second spacers on opposing sidewalls of the sacrificial mandrel. The first and second spacers are formed with an initial thickness T_S. A first angle deposition process is performed to deposit a material (e.g., insulating material or metallic material) at a first deposition angle A1 to form a first trim mask layer on an upper portion of the first spacer and the sacrificial mandrel while preventing the material from being deposited on the second spacer. A spacer etch process is performed to trim the first spacer to a first thickness T1, which is less than T_S, using the first trim mask layer as an etch mask.