This study on the main chain scission type polymers, PMMA and a copolymer system, shows that the EUV-printability is proportional to the Mw of the starting material, which is attributed to the enhanced litho-parameters of higher Mw material.

Hydrogen Silsesquioxane (HSQ) photoresist has shown extremely high-resolution performance for Electron-Beam Lithography (EBL) and Interference Lithography (IL) and can be a potential photoresist candidate for Extreme Ultraviolet Lithography (EUVL). To optimize this system for sub-10 nm patterning, it is important to understand the EUV and electron-induced chemistry underpinning the functionality of this resist material. Here we present a EUVprintability study on HSQ photoresist at a resolution of 16 and 22 nm combined with a mechanistic study on EUV and electron-induced desorption of HSQ film. Firstly, patterning results showed that the simple HSQ cages require a high EUV-dose and an aggressive developer to print dense features. EUV-and electron-induced desorption experiments revealed that hydrogen and silane are the dominant species fragmented from HSQ, indicating dehydrogenation and redistribution pathways as the crosslinking mechanism. Quantum chemical calculations suggested that the Neutral Dissociation (ND) is the dominant mechanism in HSQ cross-linking at low energies, i.e., below its ionization threshold, whereas Dissociative Ionization (DI) contributes significantly at higher energies. A distinct structure is observed at about 8 eV and a clear peak at about 11 eV indicating a significant contribution through Dissociative electron attachment (DEA) at these energies. Based on these results, an engineered HSQ system is designed by adding silanol or carbinol (R-CH3OH)-groups to the partially crosslinked HSQ-cages to increase its Tetramethylammonium hydroxide (TMAH)-developer and EUV-sensitivity. Finally, 2.38% v/v TMAH is used to develop a 16 nm printed dense line-space (L/S) with a line-edge-roughness (LER) of 6.4 nm but requiring an EUV-dose of over 100 mJ/cm 2 .

Secondary electrons generated during the Extreme Ultraviolet Lithography (EUVL) process are predominantly responsible for inducing important patterning chemistry in the photoresist film. Therefore, it is crucial to understand the electron-induced...

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