21 March 2018 Polymer effects on PAG acid yield in EUV resists
Author Affiliations +
The photo-mechanism of EUV exposures in chemically amplified photoresists are much different than that of previous lithographic wavelengths. Electrons generated during EUV exposure are demonstrated to be a source of acid production through a process referred to as electron trapping. Density functional theory modeling indicates that it is energetically favorable for the PAG molecule to decompose if an electron is trapped. Low-energy electrons unlikely to produce holes and secondary electrons generate acid indicating electron-PAG interactions are capable to induce decomposition. Additionally, a more easily reduced PAG (i.e. higher likelihood of trapping an electron) produces a higher acid yield supporting electron trapping as a process of acid production. An acid indicator, Coumarin 6, was used to determine the number of acids generated per absorbed EUV photon. The results of these measurements indicate that electron-PAG interactions are a source of acid production through electron trapping; thus, increasing the number of electron-hole pairs available to induce chemical reactions would improve sensitivity. It is expected that lower band gap materials produce more electron-hole pairs after an absorption event. Subsequently, these measurements show that lower band gap polymers generate higher acid yields.
Conference Presentation
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Steven Grzeskowiak, Steven Grzeskowiak, Jake Kaminsky, Jake Kaminsky, Sean Gibbons, Sean Gibbons, Michael Murphy, Michael Murphy, Jonathan Chandonait, Jonathan Chandonait, Robert L. Brainard, Robert L. Brainard, Greg Denbeaux, Greg Denbeaux, } "Polymer effects on PAG acid yield in EUV resists", Proc. SPIE 10586, Advances in Patterning Materials and Processes XXXV, 105860D (21 March 2018); doi: 10.1117/12.2297692; https://doi.org/10.1117/12.2297692

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