| AVS 55th International Symposium & Exhibition | |
| Electronic Materials and Processing | Thursday Sessions |
| Session EM-ThP |
| Session: | Electronic Materials and Processing Poster Session |
| Presenter: | S. Sambasivan, Suffolk Community College |
| Authors: | S. Sambasivan, Suffolk Community College V.M. Prabhu, National Institute of Standards and Technology D.A. Fischer, National Institute of Standards and Technology L.K. Sundberg, IBM Almaden Research Center R.D. Allen, IBM Almaden Research Center |
| Correspondent: | Click to Email |
Near-edge x-ray absorption fine structure (NEXAFS) spectroscopy was used to quantify the surface composition and depth profiling in the top 2 to 6 nm range of photoacid generators (PAG) in thin film photoresist materials. By considering model compositional profiles, NEXAFS distinguishes the surface molar excess within the top 6 nm from the bulk. A surface enriched system, triphenylsulfonium perfluorooctanesulfonate (TPS-PFOS), is contrasted with a perfluorobutanesulfonate (TPS-PFBS) photoacid generator, which displays an appreciable surface profile within a 6 nm segregation length scale. A comparative study of the surface composition of PAG (TPS-PFOS, TPS-PFBS and TPS-Triflate) in photoresist system before and water immersion was monitored via NEXAFS. Results reveal that the loss of PAG occurs after the water immersion in all the three different PAG system examined. Detailed quantification of the PAG loss due to water immersion was seen to critically depend on the size of the PAG and its solubility in water. TPS-PFOS photoacid generator largest in size despite its least solubility in water showed the maximum loss after water immersion followed by TPS-PFBS and TPS-Triflate. These results, while applied to 193-nm photoresist materials, highlight a general approach to quantifying NEXAFS partial electron yield data and find application to immersion lithography fundamentals.