VERTICAL OXIDE ETCH METHOD
Original Publication Date: 1990-Mar-01
Included in the Prior Art Database: 2001-Nov-15
Photoresist patterned silicon dioxide steps may be etched in a hexode reactive ion etch (WE) system without change in critical dimensions such as a taper in the oxide sidewall profile or a change in the width of the feature. Initially, a non-erodable hard mask of a material such as polysilicon is formed on top of an oxide layer to be etched. The hard mask is anisotropically etched just prior to the oxide etch. Following the anisotropic etch of the hard mask, the oxide etch is performed at very low pressure (i.e. 5 mTorr) and the etch conditions are such that a minimal amount of fluoro- carbon polymer deposits on the sides of the feature.