Pulsed laser processing of electronic materials in micro/nanoscale

Time-resolved pump-and-probe side-view imaging has been performed to investigate the energy coupling to the target specimen over a wide range of fluences. Plasmas generated during the laser ablation process are visualized and the decrease of the ablation efficiency in the high fluence regime (>10 J/cm2) is attributed to the strong interaction of the laser pulse with the laser-induced plasmas.; The high intensity ultra-short laser pulses also trigger volumetric multi-photon absorption (MPA) processes that can be beneficial in applications such as three-dimensional bulk modification of transparent materials. Femtosecond laser pulses were used to fabricate straight and bent through-channels in the optical glass. Drilling was initiated from the rear surface to preserve consistent absorbing conditions of the laser pulse. Machining in the presence of a liquid solution assisted the debris ejection. Drilling process was further enhanced by introducing ultrasonic waves, thereby increasing the aspect ratio of drilled holes and improving the quality of the holes.; In conventional lens focusing schemes, the minimum feature size is determined by the diffraction limit. Finer resolution is accomplished by combining pulsed laser radiation with Near-field Scanning Optical Microscopy (NSOM) probes. Short laser pulses are coupled to a fiber-based NSOM probes in order to ablate thin metal films. A detailed parametric study on the effects of probe aperture size, laser pulse energy, temporal width and environment gas is performed. The significance of lateral thermal diffusion is highlighted and the dependence of the ablation process on the imparted near-field distribution is revealed. As a promising application of laser ablation in nanoscale, laser induced breakdown spectroscopy (LIBS) system has been built up based on NSOM ablation configuration. NSOM-LIBS is demonstrated with nanosecond pulsed laser excitation on Cr sample. Far-field collecting scheme by top objective lens was chosen as a first approach.; As another useful application of NSOM based laser processing, the pyrolytic NSOM laser chemical vapor deposition (LCVD) of silicon dots on crystalline silicon wafer by the decomposition of SiH4 has been demonstrated. Nanosecond laser pulses of visible wavelength were coupled through NSOM fiber probe in order to obtain sub-100nm synthesized features with various laser pulse energies.; Polymer based photolithography and ablation lithography was performed by both objective lens and NSOM probe schemes. Femtosecond laser pulses generated features of high aspect ratio and sub-diffraction limit size due to non-linear beam propagation and MPA process. Development of ultra-thin film process is essential for NSOM probe based processing. Photosensitive dendritic surface monolayer films were successfully tested in order to fabricate both ablative (negative) and self-assembled (positive) features using objective lens focused femtosecond laser pulses of 400 nm wavelength. (Abstract shortened by UMI.)...