LINE WIDTH ROUGHNESS CONTROL WITH ARC LAYER OPEN

摘要

To achieve the foregoing and in accordance with the purpose of the present invention a method for etching an etch layer disposed below an antireflective coating (ARC) layer below a patterned mask is provided. The ARC layer is opened, and features are etched into the etch layer through the patterned mask. The opening the ARC layer includes (1) providing an ARC opening gas comprising a halogen containing gas, COS, and an oxygen containing gas, (2) forming a plasma from the ARC opening gas to open the ARC layer, and (3) stopping providing the ARC opening gas to stop the plasma. The patterned mask may be a photoresist (PR) mask having a line-space pattern. COS in the ARC opening gas reduces line width roughness (LWR) of the patterned features of the etch layer.