Analysis of resist pattern collapse and optimization of DUV process for patterning sub-0.20-um gate line

摘要

Abstract: We analyzed the local pattern collapse by KLA-2132 in patterning gate line of 0.18 $mu@m on the Poly-Si/WSix/Si$- 3$/N$-4$/, where the thickness variation of Si$-3$/N$-4$/ (Nitride) film affected on the substrate reflectivity. By thickness split experiments of organic bottom anti- reflective layers (ARLs), we showed the effect of thickness variation of Nitride on the resist pattern collapse. We investigated the contribution of various factors to the pattern collapse. First of all, we focused on the CD variation due to substrate reflectivity variation to remove patterns of tolerable aspect ratio. In order to obtain better CD uniformity by tight reflectivity control considering the thickness variation of Nitride film, we optimized anti-reflective layer process using inorganic ARLs. As an inorganic ARL, we used PECVD SiOxNy:H(SiON) of which optical constants were changed by deposition conditions. We compared typical positive-tone DUV resists, of acetal based with environmentally stable chemically amplified photoresist type, to clarify the effect of resist and organic bottom ARL materials.!5