Photocurable positive photoresist‐comprising copolymers having pendant alkoxy ethyl moieties

Abstract

A series of copolymers based on methacrylic acid (MAA), methyl methacrylate (MMA), n-butyl methacrylate (BM), and bornyl methacrylate (BMA) with various feed molar ratios were synthesized. To introduce the protecting alkoxy ethyl moieties onto copolymers, the pendant carboxyl groups were further reacted with alkyl vinyl ether. The pendant alkoxy ethyl groups on copolymers could be deprotected by acid catalyst. Characterization of positive-tone photoresist-comprising copolymers having pendant alkoxy ethyl groups was carried out. Effects of alicyclic bornyl groups on the sensitivity and thermal properties of copolymers were investigated. It was found that the existence of bornyl groups in polymer might interfere with the hydrogen bonding produced by pendant carboxyl groups, leading to the decrease of thermal resistance. Acid-catalyzed dehydration crosslinking of pendant carboxyl groups of copolymers was also investigated. The exposure characteristic curves and the lithographic evaluation of the positive-tone photoresist were all investigated. Effects of alicyclic bornyl groups on the plasma etching resist of copolymers were also evaluated.

Atom Transfer Radical Polymerization of 1-Ethoxyethyl (Meth)acrylate: Facile Route toward Near-Monodisperse Poly((meth)acrylic acid)

“…This simple deprotection step without the need for further purification adds new prospects for the use of these polymers in thermoresponsive systems and in applications where a change from hydrophobic to hydrophilic properties is needed, for instance in photoresist technology . Even reversible systems are possible …”

“…17 Even reversible systems are possible. 18 The monomers, 1-ethoxyethyl methacrylate (EEMA) and 1-ethoxyethyl acrylate (EEA), were synthesized by the acid-catalyzed addition reaction of (meth)acrylic acid to ethyl vinyl ether, 19 as previously described 20 (see Scheme 1).…”

Preparation and characterization of molecular photoresists: Crosslinkable positive and water developable negative tones

“…The chemical amplification resist system is a potential future photolithographic technology using a new irradiation method 9–12. In this system, a generating acid is produced in a photo‐acid generator when light is present, which promotes deprotection of the protecting groups, such as t ‐butyl ester, acetal, trimethylsilyl, and tetrahydropyranyl groups to achieve higher resolution resist materials 13–16. Recently, many new chemical amplification photoresist materials have been reported using various polymers containing fluorine atoms and alicyclic groups, such as adamantane and norbornane 17, 18.…”

“…[9][10][11][12] In this system, a generating acid is produced in a photo-acid generator when light is present, which promotes deprotection of the protecting groups, such as t-butyl ester, acetal, trimethylsilyl, and tetrahydropyranyl groups to achieve higher resolution resist materials. [13][14][15][16] Recently, many new chemical amplification photoresist materials have been reported using various polymers containing fluorine atoms and alicyclic groups, such as adamantane and norbornane. 17,18 From these studies, it seems that material molecular size is one of the important factors to achieve ultra-high resolution.…”