Study on Ashing-less Dry Etching Process to Eliminate Q-time Defect Formation

The Q-time limit is one of the factors influencing the productivity and yield of the semiconductor device in manufacturing process. In general, most dry etching processes leave gaseous by-products on the wafer, and Q-time defects occur when the following step is delayed. Therefore, at the development stage of a dry etching scheme, it is important to consider proper post-treatment for eliminating residual gas. O 2 plasma ashing and DSP (Diluted Sulfuric Peroxide) stripping are typical post-treatment methods for dry etching process. However, some mask materials for dry etching may be damaged by such post-treatments, so the reactivity of mask films, the treatment conditions, and the chemical properties of residual gas must be considered. This paper discusses the effective removal of ionic Q-time defects and the determination of the appropriate Q-time limit margin for dry etching process employing mask films that are susceptible to post-treatment conditions.