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25 February 2002 Laser-induced rear ablation of metal thin films
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Proceedings Volume 4426, Second International Symposium on Laser Precision Microfabrication; (2002)
Event: Second International Symposium on Laser Precision Micromachining, 2001, Singapore, Singapore
The purpose of this study is to investigate the correlation between Laser Induced Forward Transfer (LIFT) process observed experimentally and the deposited structure, especially the size accuracy. Ablated plume and shadowgraph of transferring materials were observed using image intensified CCD camera. The intensity of reflected He-Ne laser from the front and rear side of thin films, respectively, were measured using photodiode to investigate the behavior of thin film during laser pulse. Metal thin films (Au and Ni), with several tens - hundreds of nanometer in thickness deposited on quartz substrate using ion sputtering deposition method, were irradiated by KrF excimer laser (wavelength 248 nm, pulse width 30 ns). The measurement of the reflected He-ne laser shows that the film removal finishes during incident laser pulse. Ablated plume images and shadowgraphs of transferring materials show that the velocity of both the top of ablated plume and the transferring materials become faster in increase fo fluence, and that the transferring materials precede the plume. Optimum fluence exists at each film thickness to achieve high size accuracy of deposited structure. At lower fluence, the deposited structure shows bad feature due to incomplete removal from the support substrate. At higher fluence, the big shock causes the wide range of spread of deposited structure when the transferring particles have a collision with the acceptor substrate. At optimum fluence, the high size accuracy of deposited structure is achieved as the film-substrate distance is made as short as possible.
© (2002) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Tomokazu Sano, Hirokazu Yamada, Takayuki Nakayama, and Isamu Miyamoto "Laser-induced rear ablation of metal thin films", Proc. SPIE 4426, Second International Symposium on Laser Precision Microfabrication, (25 February 2002);

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