Multicomponent negative-type photoresist based on Noria analog with 12 ethoxy groups

Abstract

The characteristics of Noria analogs with 12 ethoxy groups and 12 hydroxy groups (Noria-OEt), which were synthesized by the condensation reaction of 3-ethoxyphenol with 1,5-pentanedial, were examined in detail. The solubility of the synthesized Noria-OEt in common organic solvents was better than that of Noria. In addition, Noria-OEt was soluble in 2.38 wt% tetrametyl ammonium hydroxide (TMAH) aqueous as a developer. The thermal stability and mechanical properties were similar to those of Noria because of the ladder structure and amorphous characteristics, which means that the film-forming properties were confirmed. These characteristics are advantageous for use as a molecular glass photoresist. The patterning properties of the negative-type, alkaline developable, multicomponent photoresist based on Noria-OEt, with polyfunctional benzyl alcohols as a crosslinker and a photoacid generator, were evaluated with an extreme ultraviolet lithography system. This negative-type photoresist with 2,4-dihydroxymethyl-6-methylphenol as a crosslinker gave a resolution pattern of 35 nm half-pitch with 10.0 mJ cm−2. We synthesized Noria analogs (Noria-OEt) with 12 ethoxy groups and 12 hydroxy groups by the condensation reaction of 3-ethoxyphenol with 1,5-pentanedial in high yield and prepared negative-type photoresist composed of Noria-OEt, crosslinker, photoacid generator and quencher. The negative-working photoresist gave a resolution pattern of 35-nm half-pitch with high sensitivity (10.0 mJ cm−2) by an extreme ultraviolet (EUV) lithography system.