Laser-Induced Growth of Microstructures

Abstract

In the field of microelectronic devices, laser-induced processes are currently under investigation for various applications such as wafer marking, substrate cleaning, doping, oxidation, etching, deposition of thin films, exposure or removal of photoresists and recrystallization of silicon on insulators [1]. Laser irradiation of reactant gases can generate activated species on the substrate surface and localized growth of microstructures can be achieved by focusing a laser beam on absorbing substrates. Owing to small laser beam diameters and high energy densities (fluences), very high reaction rates are obtained. The laser spot can be positioned and automatically moved over the substrate surface making one step fabrication of microstructures possible. This “direct writing” technique is very promising to establish new interconnection networks in very-large scale integrated (VLSI) circuits through laser-induced chemical vapor deposition (LCVD) and etching. With such processes, semiconductor devices have been fabricated without using masks [2]. Laser processing is a way of obtaining the precision required in the microelectronic industry for integrated circuits with micron and submicron sizes. Review papers have been published on laser-generated microstructures [3] as well as laser-induced CVD [4–7] and laser-microchemical processing for VLSI [8–12].