Title: Lithographic applications of excimer laser exposures of polymeric films.
Abstract: KrF excimer laser lithography is a major candidate for sub-half micron VLSI technology, although it has many problems. The main topics of the present paper is not the excimer laser lithography, but a lithographic application of excimer laser photoablation, and surface modifications of polymer films, including silylation and metallization induced by excimer laser irradiation. Because the main application of excimer laser ablation is contact hole fabrication, photoablation of Teflon or Teflon like materials is important. We carried out photoablation of Teflon AF (a copolymer of tetrafluoroethylene and 2, 2-bis(trifluoromethyl)-4, 5-difluoro-1, 3-dioxolene) using a dopant at 193 and 248nm. High temperature resistant polymers like polyimides and polyphenylquinoxaline show imagewise wetting after excimer laser exposure in air, giving rise to direct surface silylation of these materials. Although we have not carried out image transfer experiments yet, XPS data clearly showed silicon incorporation. Imagewise metallization of these polymer surfaces after ArF excimer laser exposure in air showed some interfacial compound formations between exposed polymer surfaces and metal deposited. The XPS data of gold on PPQ exposed in air will be discussed.Effects of excimer laser exposures on polymer surfaces are repoorted, which include photoablation of Teflon AF by ArF and KrF excimer laser pulses, and surface modifications of some unsolved questions of the nature of interactions between deposited metals and laser exposed polymer surfaces. The study on these problems are in progress.