Surface modification of hydrogenated amorphous carbon (a-C: H) films prepared by plasma enhanced chemical vapor deposition (PECVD)

Methods to modify the film surface of hydrogenated amorphous carbon (a-C: H) produced by PECVD have been studied. One way is to expose the film to O2-H2 plasma atmosphere, the topographical nature of the resulting surface can be modified substantially due to reaction of O2-H2 plasma with active ions and radicals, and therefore ashed carbon away with thickness decrease. The other way is to immerse films into O3-diluted deionized (DI) water. Free radicals produced at the surface during the PECVD process were quenched by reaction with oxygen and/or water and an oxidized hydrophilic layer was formed at the surface. Therefore, the film thickness, either optically measured by KLA tools or physically demonstrated with TEM images, has proven to be increased, different from that of dry physical etching.