Relationship between film thickness loss and polymer deprotection for extreme ultraviolet and ArF photoresists

摘要

The authors report on the relationship between the film thickness loss (FTL) and the polymer deprotection of chemically amplified resists with chemistries for ArF and extreme ultraviolet lithography. FTL curves are quickly and easily accessed experimentally through in-line ellipsometry measurements. They also provide affordable and valuable input for the description of acid generation and polymer deprotection kinetics for resist modeling. Unlike 248 nm resist platforms, where a linear relationship has been observed between the polymer deprotection and the FTL, they observe that for 193 and 13.5 nm technologies, the polymer composition induces a deviation from this linearity. In particular, the authors use Fourier transform infrared spectroscopy for the evaluation of the polymer deprotection in both model resists (with known chemical properties) and state-of-the-art commercial resists. With the corresponding FTL, chemical components that contribute to the nonlinearity are identified.