Optimization of laser-induced forward transfer process of metal thin films

The optimization of laser-induced forward transfer (LIFT) process using laser ablation of thin film and the evaluation of the dependence in laser spot size on the resolution of deposited material are reported. Ni thin film of several hundred of nanometer thickness, which is deposited on fused silica substrate, was irradiated by single pulse of KrF excimer laser (wavelength: 248 nm, pulse width: 30 ns), and transferred to a Si acceptor substrate. Images of the plume, which were photographed using image intensified CCD camera, indicated the cause of transfer of particles. The deposited material with clear contour was obtained under the condition that thin film was in contact with an acceptor substrate to inhibit the transfer of particles which were generated by laser irradiation. The resolution of a deposited material tended to be improved as the size of laser spot became smaller. (C) 2002 Elsevier Science B.V. All rights reserved.