A novel approach to chemically amplified resist materials for next generation of lithography

Chemically amplified resists (CARs) would be one of the most promising candidates for the next generation of lithographic resist materials. The key difficulty in the 193nm (ArF) and 157nm (F/sub 2/) photoresist design was the apparent inability to meet etch resistance, optical transparency, sensitivity and line edge roughness. Avenues that can lead to the etching resistant polymer include the incorporation of alicyclic moieties and optical transparency. They can be improved by appropriate placement of electron-withdrawing group, such as fluorine into a polymer structure. And chemical amplification solves the sensitivity problem. In general, the CARs composed of the linear structure of polymers and photosensitive catalysts have been used. The chain entanglement inherent to linear polymers may hinder lithographic imaging at molecular scale dimensions in next generation lithography. In this work, we suggest a new concept to solve this point. We prepared the nanoparticle sizes ranging from 20-50nm by intramolecular self-crosslinking of methylmethacrylate (MMA), 2-hydroxyethyl methacrylate (HEMA) and tert-butyl methacrylate (t-BOC) terpolymer in an ultra dilute solution. These materials are characterized by NMR spectroscopy, SEM, GPC, FT-IR, exposure system and TGA. These resists which are not affected by intermolecular chain entanglement may decrease line edge roughness (LER) at very small feature size.