| abstract |
A method of etching features in a stack including a dielectric material on a substrate is provided. In step (a), an etching plasma is generated from an etching gas, the stack is exposed to the etching plasma, and features in the stack are partially etched. In step (b), an atomic layer deposition process is provided to deposit a protective film on the sidewalls after step (a). The atomic layer deposition process includes a plurality of cycles, wherein each cycle includes exposing the stack to a first reactant gas comprising WF 6 , wherein the first reactant gas is adsorbed to the stack and exposing the stack to a plasma formed from a second reactant gas, wherein the plasma formed from the second reactant gas reacts with the adsorbed first reactant gas to form a plasma in the stack A protective film is formed over the parts. In step (c), steps (a)-(b) are repeated at least once. |