Method for forming contact openings on a MOS integrated circuit

摘要

A method for forming contact openings in various locations of the upper surface of an integrated circuit having raised areas, critical openings having to be formed between two neighboring raised areas, including the steps of covering the entire structure with a first protection layer; forming non-critical openings in the first protection layer; coating the structure with a second protection layer; performing an oblique irradiation so that the second protection layer is not irradiated at the bottom of the regions located between two raised areas; removing the non-irradiated portions of the second protection layer; removing the portions of the first protection layer located under the second protection layer at the locations where this second protection layer has been removed; and removing the irradiated portions of the second protection layer.