Etching method and recipe for forming high aspect ratio contact hole

摘要

Disclosed is an etching method for forming a high aspect ratio contact hole. The plasma gas composition for the etching comprises Ar, a first fluorocarbon, O2 and a second fluorocarbon, wherein the fluorine-to-carbon ratio of the second fluorocarbon is higher than that of the first fluorocarbon. The method of the present invention can maintain the profile of the contact hole well, and reduce the accumulation of the etch stop generated during etching.