Optimization of 193-nm single-layer resists through statistical design

Abstract

Through a series of statistical design experiments we optimized the lithographic performance of a 193 rim single layer resist based on a norbomene-maleic anhydride matrix resin. Several interesting findings were found including that having the PEB temperature higher than the SB temperature improved the performance of the resist. The polymer composition was found to strongly influence the lithographic performance of the resist. Variables that we examined included acrylate loading and blocking level. By optimizing the composition of the polymer, we have obtained resists with high etch resistance, square profiles and 0. 130 micron dense line ultimate resolution in 0.5 micron thick films. The resist formulations are compatible with industry standard 0.262 N TMAH. During exposure the resist does not suffer from the outgassing of volatile species (less than 2 molecules/cm2 x sec).

Fundamental Investigations of the Free Radical Copolymerization and Terpolymerization of Maleic Anhydride, Norbornene, and Norbornene tert-Butyl Ester: In-Situ Mid-Infrared Spectroscopic Analysis

“…A variety of synthetic routes for producing resist materials with alicyclic backbones have been investigated. For example, cyclic olefin alternating free radical copolymerization, − metal-catalyzed vinyl addition polymerization, ,,− and ring-opening metathesis polymerization (ROMP) followed by hydrogenation. , In recent years, the most promising of these methods that has emerged for synthesizing alicyclic materials for 193 nm lithography is the alternating free radical copolymerization of maleic anhydride with cyclic olefin monomers such as norbornene (Scheme ). ,, Cyclic olefins will homopolymerize poorly via free radical methods. However, norbornene is a cyclic olefin that contains bridged allylic hydrogens that do not chain transfer to an appreciable extent due to the resulting unstable radical .…”

“…12 A variety of synthetic routes for producing resist materials with alicyclic backbones have been investigated. For example, cyclic olefin alternating free radical copolymerization, [22][23][24][25][26][27][28][29][30] metal-catalyzed vinyl addition polymerization, 23,24,[31][32][33] and ring-opening metathesis polymerization (ROMP) followed by hydrogenation. 23,24 In recent years, the most promising of these methods that has emerged for synthesizing alicyclic materials for 193 nm lithography is the alternating free radical copolymerization of maleic anhydride with cyclic olefin monomers such as norbornene (Scheme 1).…”