Method of forming a contact hole in a semiconductor wafer

摘要

The present invention provides a method of forming a contact hole in a semiconductor wafer. The semiconductor wafer comprises a silicon substrate, a silicon-oxygen layer positioned on the silicon substrate, and a photoresist layer positioned on the silicon-oxygen layer. An anisotropic dry-etching process is performed to vertically remove the silicon-oxygen layer below the opening to a predetermined depth to form the contact hole which contains a polymer layer on its surface. A soft-etching process is performed to remove the polymer layer in the contact hole. The dry-etching process and soft-etching process are performed alternatively to vertically remove the silicon-oxygen layer under the contact hole until the surface of the silicon substrate can be reached through the contact hole.