CONTACT HOLE FORMING METHOD

摘要

The method for reducing the aspect ratio of contact hole form, solves problems of metal step coverage in depositing metal. The method for forming a contact hole on oxidized film (2) deposited on silicon substrate (1), comprises the steps of: forming contact hole pattern (3a) on photosensitive film (3) by a photo mask process; dry-etching primary contact hole (2a) with a certain depth (h1) on the film (2) by freon gas plasma; dry-etching the film (3) with a certain width (W) by oxygen gas plasma; dry-etching secondary contact hole (2b) with a certain depth (h2) by freon gas plasma; over-etching the film (2) by freon gas plasma with high C/F ratio after dry-etching the film (2) by freon gas plasma and widening the film (3) by oxygen gas plasma; removing the film (3) on the oxidized film (2) by H2SO4/H2O2 solution.