Judy Wang, Shing-Li Sung & Shawming Ma, Applied Materials, USA

ABSTRACT

Contact-hole distortion results from low mask selectivity and poor mask surface quality (roughness, striation, pitting, or pin holes) before or after etching.  Thinner, softer ArF resists are particularly susceptible to these defects, giving rise to the need for additional steps in the etch sequence to mitigate pattern deformation.  Experimentation with a polymer deposition process shows that by adding this step before, after or before and after the bottom anti-reflective coat (BARC) open step, mask quality is much improved and contact profiles can be well controlled.