RECENT PROGRESS IN CHEMICAL AMPLIFICATION RESISTS FOR EXCIMER LASER LITHOGRAPHY: REVERSE POLARITY CHANGE VIA PINACOL REARRANGEMENT

Abstract

Chemical amplification resists based on the reverse polarity change from a polar to a nonpolar state have been designed. The imaging mechanism relies on the pinacol-pinacolone rearrangement, wherein vic-diols (pinacols) are converted to ketones or aldehydes with photochemically generated acid as a catalyst. A polymeric pinacol has been synthesized and has demonstrated very efficient and clean rearrangement to provide negative images upon development with methanol. Small pinacol compounds have been also utilized in three-component, aqueous base developable, negative resist systems, where the rearrangement products inhibit the dissolution of the phenolic matrix resin in the exposed regions.