Study of PAG Material Design for ArF Immersion Photoresist

One of some critical issues for ArF immersion lithography was leaching of resist components to water fluid. To decrease the leaching amount, increase hydrophobicity of Photo Acid Generator (PAG) was one of the most effective methods. The hydrophobicity of PAG was detected by simulating Log-P value and measuring Retention Time (RT) on reversed phase chromatography. However, simple high hydrophobic PAG indicated high defect number. The improvement of this issue was achieved by introducing acid cleavable group into PAG cation frame. It may suggest that PAG material proposed on this study showed low leaching amount and low defect risk as new concept for ArF immersion resist.