A method of making an integrated circuit comprises providing a substrate and forming a structure on the substrate comprising a first enclosed portion of a carbon material and a second portion of the carbon material, wherein an intersection of the first and second portion of the carbon material has a defined dimension. The method further comprises processing the substrate with a plasma comprising hydrogen in order to etch the second portion of the carbon material, wherein the defined dimension of the intersection of the first and second portion of the carbon material substantially suppresses etching of the first enclosed portion of the carbon material in a self-limiting way.