A novel approach to <i>o</i>-nitrobenzyl photochemistry for resists

Abstract

We have developed a two-component (resin-solution inhibitor) resist system having good photosensitivity in the 230–300 nm range. The resin is an optically transparent methyl methacrylate-methacrylic acid copolymer that is soluble in aqueous alkali. The second component is one of a family of o-nitrobenzyl carboxylates that are initially insoluble in the alkaline developer but are cleaved to soluble components upon irradiation. A number of o-nitrobenzyl alcohol esters have been prepared and examined for use in this two-component system. They have proven useful in the development of sensitive high-resolution short-wavelength photoresists which are described.