Proton Transfer to Melamine Crosslinkers in X-Ray Chemically Amplified Negative Resists Studied by Time-Resolved and Steady-State Optical Absorption Measurement

Abstract

Proton transfer to melamine crosslinkers has been analyzed in three X-ray chemically amplified (CA) negative resists. One is an in-house fabricated resist composed of m-cresol novolac, 2,4,6-tris (trichloromethyl)-1,3,5-triazine (TCT), and hexamethoxymethylmelamine (HMMM). The other two are commercially available resists: SAL-601 (Shipley Co.) and AZ-PN 100 (Hoechst Co.). The behavior of protons induced by X-ray exposure was analyzed using both conventional steady-state optical absorption spectroscopy and nanosecond time-resolved absorption spectroscopy (pulse radiolysis). The results indicate that the protons are transferred from the proton adducts (acid precursors) of matrix polymers to the melamine crosslinker in a very early step. This proton transfer was much faster than that from the proton adducts of matrix polymers to dissolution inhibitors in CA positive resists.