Patent ID: 7425277
Filing Date: 2008-09-16
Classification: H01L

Abstract:
1. A method for etching, comprising: positioning a substrate at a location to be exposed to a source of high density plasma, the substrate having a topmost layer of inorganic mask material disposed directly over a layer of silicon nitride, wherein each of the inorganic mask material and silicon nitride layers have regions that are substantially parallel to the source and regions that are not parallel to the source; setting the high density plasma to isotropically contact the inorganic mask material on both the regions that are substantially parallel to the source and the regions that are not parallel to the source, the contact causing the inorganic mask material to be removed to expose the silicon nitride regions that are substantially parallel to the source while leaving the silicon nitride regions that are not parallel to the source covered by remaining portions of inorganic mask material; and setting the high density plasma to remove the exposed silicon nitride regions that are substantially parallel to the source, the remaining portion of inorganic mask material preventing the removal of silicon nitride from the regions that are not parallel to the source.