Neutron Reflectivity Characterization of the Photoacid Reaction-Diffusion Latent and Developed Images of Molecular Resists for Extreme Ultraviolet Lithography
- National Inst. of Standards and Technology (NIST), Gaithersburg, MD (United States). Polymers Division
- Cornell Univ., Ithaca, NY (United States). Dept. of Materials Science & Engineering
- Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Center for Nanophase Materials Science (CNMS)
- National Inst. of Standards and Technology (NIST), Gaithersburg, MD (United States). Center for Neutron Research
Lithographic feature size requirements have approached a few radius of gyration of photoresist polymers used in thin-film patterning. Furthermore, the feature dimensions are commensurate with the photoacid diffusion length that defines the underlying latent image. Smaller imaging building blocks may enable reduced feature sizes; however, resolution limits are also dependent upon the spatial extent of the photoacid-catalyzed reaction diffusion front and subsequent dissolution mechanism. The reaction-diffusion front was characterized by neutron reflectivity for ccc stereoisomer-purified, deuterium-labeled tert-butoxycarbonyloxy calix[4]resorcinarene molecular resists. The spatial extent of the reaction front exceeds the size of the molecular resist with an effective diffusion constant of (0.13 ± 0.06) nm2/s for reaction times longer than 60 s, with the maximum at shorter times. Comparison to a mean-field reaction-diffusion model shows that a photoacid trapping process provides bounds to the spatial and extent of reaction via a reaction-limited mechanism whereas the ratio of the reaction rate to trapping rate constants recovers the effective diffusion peak. Finally, under the ideal step-exposure conditions, surface roughness was observed after either positive- or negative-tone development. However, negative-tone development follows a surface restructuring mechanism rather than etch-like dissolution in positive-tone development.
- Research Organization:
- Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States). Center for Nanophase Materials Sciences (CNMS)
- Sponsoring Organization:
- USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22); National Science Foundation (NSF)
- DOE Contract Number:
- AC05-00OR22725
- OSTI ID:
- 1039978
- Journal Information:
- Langmuir, Journal Name: Langmuir Journal Issue: 20 Vol. 28; ISSN 0743-7463
- Publisher:
- American Chemical Society
- Country of Publication:
- United States
- Language:
- English
Similar Records
Characterization of the non-uniform reaction in chemically-amplified calix[4]resorcinarene molecular resist thin films
Architectural Effects on Reaction-Diffusion Kinetics in Molecular Glass Photoresists