Etch rate modulation through ion implantation

A method of processing a workpiece, comprising:

• creating an opening in a silicon nitride mask disposed on a silicon dioxide layer, the silicon dioxide layer disposed on a surface of the workpiece, so as to expose a portion of the silicon dioxide layer disposed beneath the mask;
• implanting an etch rate modifying species into the mask and the portion of the silicon dioxide layer;
• and
• etching the portion of the silicon dioxide layer;
• wherein the etch rate modifying species increases a difference between an etch rate of the silicon nitride and an etch rate of the silicon dioxide layer by at least a factor of two.

A method of processing a workpiece, comprising:

• creating an opening in a silicon nitride mask disposed on a surface of the workpiece, so as to expose a portion of a material disposed beneath the mask;
• implanting an etch rate modifying species into the mask and the portion of the material disposed beneath the mask;
• and
• etching the portion of the material disposed beneath the mask;
• wherein the etch rate modifying species increases a difference between an etch rate of the silicon nitride and an etch rate of the material, and wherein the etch rate modifying species comprises carbon, silicon, germanium or nitrogen.