High-etch-rate ArF BARC composed of polyester

Abstract

As the pattern size decreases, the thickness of resist also should be decreased owing to the pattern collapse problem. So the using of surfactant containing rinse material, instead of DI water, can be a solution to the collapse problem. The developing of Bottom Anti Reflective Coating (BARC) that has high etch rate will be helpful to the collapse issue because it enables low thickness resist process and pattern collapse will be decrease. In this paper, Polyacetal, polyacrylate and polyesters BARCs were evaluated. Polyacetal type BARC shows best coating property. Regardless of the topology, polyacetal type BARC shows good conformality. However, polyacrylate and polyesters show coating fail on the topology wafer. In terms of pattern collapse, polyacetal type BARC also shows best results. Among the three types of BARC, ArF BARC that is made by polyester resin shows highest etch rate after 2000ÅBRAC etch. However, when the etching target is 60nm, all BARCs have same etch rate. For the matching with line and space resist, all these three BARCs show good profile. However, polyester type BARC does not match with contact hole resist and could not define contact hole pattern.