Patent ID: 6147007
Filing Date: 2000-11-14
Classification: H01L

Abstract:
A method for forming a contact hole on a semiconductor wafer, the semiconductor wafer comprising a substrate, a silicon nitride (SiN) layer positioned on the substrate, a silicon oxide layer positioned on the silicon nitride layer, and a photo-resist layer positioned on the silicon oxide layer, the photo-resist layer comprising a hole, the method comprising:performing a first anisotropic etching process in a downward direction to remove the silicon oxide layer under the hole down to the surface of the silicon nitride layer to form a recess, wherein polymer material remains at the bottom of the recess following this first anisotropic etching process;performing an in-situ plasma cleaning process to entirely remove the polymer material remaining at the bottom of the recess; andperforming an in-situ second anisotropic etching process in a downward direction to remove the silicon nitride layer from the bottom of the recess down to the surface of the substrate to form the contact hole.