The synthesis and lithographic evaluation of 193-nm and EUV photoresists that utilize a higher-order reaction mechanism of deprotection is presented. Unique polymers utilize novel blocking groups that require two acid-catalyzed steps to be removed. When these steps occur with comparable reaction rates, the overall reaction can be higher order (≤ 1.85). The LWR of these resists is plotted against PEB time for a variety of compounds to acquire insight into the effectiveness of the proposed higher-order mechanisms. Evidence acquired during testing of these novel photoresist materials supports the conclusion that higher-order reaction kinetics leads to improved LWR vs. control resists.
This paper presents two new concepts that together provide a 100,000X improvement in stability
for AAs that produce highly-fluorinated, strong sulfonic acids. These two new design concepts are
based on (1) an olefin-trigger structure and (2) a trifluoromethyl group alpha to the sulfonic ester.
These new concepts led to the synthesis of the first stable acid amplifier that generates triflate acid
and for the synthesis of AAs that are stable enough to be used as monomers in free-radical
polymerization reactions yet produce very strong, fluorinated acids. Lastly, we present preliminary
results where one new AA is able to improve the LER of a control resist from 4.6 ± 0.5 nm to 2.1 ±
A novel series of stable, acid amplifiers (AAs) has been designed and tested for use in Extreme Ultraviolet
(EUV) lithography, that generate strong, fluorinated polymer bound sulfonic acids. Novel polymer bound and
blended AAs were prepared in moderate to good yields and characterized by NMR. We demonstrated by EUV
lithography that the polymer bound AA resist has line-edge roughness (LER) values of 3.8 nm and the
polymer blended AA resist has LER values of 2.1 nm while the control resist has LER values of 4.6 nm.
Although sensitivity comparisons have yet to be made, these new resists using bound and blended AAs are
showing remarkable improvements in LER when compared with the control resist without AAs.