NEXAFS Measurements of the Surface Chemistry of Chemically Amplified Photoresists

Published

September 1, 2003

Author(s)

E Jablonski, M Angelopoulos, H Ito, Joseph~undefined~undefined~undefined~undefined~undefined Lenhart, S Sambasivan, Daniel A. Fischer, Ronald L. Jones, Eric K. Lin, Wen-Li Wu, D L. Goldfarb, K Temple

Abstract

Near edge x-ray absorption fine structure (NEXAFS) spectroscopy was used to quantify the surface composition profile (top 1 nm to 6 nm) of model chemically amplified photoresists with various photo-acid generators. These materials are prone to interfacial and surface phenomena that cause deviations in the desired lithographic pattern such as T-topping and closure. If interfacial excess or depletion of the photo-generated acid occurs, either from atmospheric contamination, evaporation, or segregation within the film, the resulting compositional heterogeneity will affect the interfacial photoresist structure, composition, and deprotection kinetics. A significant technical challenge lies in measuring the surface composition and extent of reaction with high resolution at interfaces. NEXAFS allows measurement of the surface chemical composition, particularly for carbon, fluorine, oxygen, and nitrogen. When exposed to vacuum ultraviolet x-rays, the top surface of the material releases Auger electrons that can be measured with an electron yield detector. By varying the negative voltage bias at the entrance to the electron yield detector, it is possible to differentiate Auger electrons escaping from depths up to 6 nm into the film. This measurement capability becomes increasingly important with the drive towards sub?100 nm lithography. As the photoresist film thickness continually decreases and the interfacial regions dominate the behavior of the material, it is crucial to understand both their physical and chemical nature.

Proceedings Title

Characterization and Metrology for ULSI Technology, International Conference | | Characterization and Metrology for ULSI Technology: 2003 International Conference on Characterization and Metrology for ULSI Technology | AIP

Volume

683

Conference Dates

March 1, 0024

Conference Title

AIP Conference Proceedings

Pub Type

Conferences

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Keywords

NEXAFS, photo-acid generator, photoresist, surface chemistry

Citation

Jablonski, E. , Angelopoulos, M. , Ito, H. , Lenhart, J. , Sambasivan, S. , Fischer, D. , Jones, R. , Lin, E. , Wu, W. , Goldfarb, D. and Temple, K. (2003), NEXAFS Measurements of the Surface Chemistry of Chemically Amplified Photoresists, Characterization and Metrology for ULSI Technology, International Conference | | Characterization and Metrology for ULSI Technology: 2003 International Conference on Characterization and Metrology for ULSI Technology | AIP, [online], https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=852164 (Accessed October 15, 2024)