HSQ with high plasma etching resistance surface for borderless vias

摘要

HSQ is employed for gap filling patterned metal layers. The surface of the deposited HSQ gap fill layer is modified to decrease its plasma etching rate. Embodiments include modifying the HSQ surface by exposure to a plasma, such as a nitrogen-containing plasma, e.g., a plasma containing ammonia or hydrogen/nitrogen, to form a nitrided surface region. Reduction of the plasma etching rate of HSQ enables formation of reliable low resistance borderless vias.