Protonation Sites in Chemically Amplified Resists for Electron-Beam Lithography

Abstract

In chemically amplified resists that utilize acid-catalytic reactions for pattern formation, proton dynamics is important from the viewpoints of the insoluble layer formation due to acid loss, the resolution decrease due to acid diffusion, and the image quality improvement due to base-quencher effects. For electron-beam lithography, the protons and anions of the acid are initially generated at different places. Protons migrate in the resist matrix toward counter anions, attracted by the opposite electric charges. However, the details of proton migration are still unclear. In this study, we investigated proton quenching in poly(4-hydroxystyrene) films using base quenchers with different proton affinities. When the proton affinity of the base quencher was increased, the equimolecular proton adduct of the acid-sensitive dye was quenched without postexposure bake. Although the proton affinity is a gas-phase value, the quenching effect correlated well with the proton affinity.

Relationship between Sensitization Distance and Photon Shot Noise in Line Edge Roughness Formation of Chemically Amplified Resists Used for Extreme Ultraviolet Lithography

“…The preneutralization of acids before PEB [17,18] was assumed because an annealingtype resist is generally used in EUV lithography. The proton migration range at room temperature was set to 2.4 nm [19].…”

Requirement for Suppression of Line Width Roughness in Fabrication of Line-and-Space Patterns with 7 nm Quarter-Pitch Using Electron Beam Lithography with Chemically Amplified Resist Process

“…The preneutralization of acids before PEB [16,17] was assumed because an annealing-type resist is generally used in EB lithography. Using the acid distribution after the preneutralization as the initial condition, the catalytic chain deprotection during PEB was calculated by solving the reaction-diffusion equations for acids and quenchers.…”

Challenges in Development of Sub-10 nm Resist Materials

“…The preneutralization of acids before PEB [24,25] was assumed because annealing-type resists are generally used in EUV lithography. The proton migration range at room temperature was set to be 2.4 nm [26].…”