Laser Micromachining of Silicon and Glass Motivations Explore the impact of nanosecond pulses of IR to UV wavelengths on rate of micromachining of Si and Glass Study the effect of high repetition rate, spot diameters, interaction time on micromachining of Silicon and Glass Evaluate laser threshold fluence of nanosecond IR and UV wavelengths for ablation of silicon and glass Objectives Short Pulse Multi-Wavelength Micromachining: A) Silicon Numerical Simulation of Crator Morphology: Experimental Set-up PhD candidate: Shiva Gadag Advisor: Prof. Dr. Radovan Kovacevic Department of Mechanical Engineering Conclusions: Feasibility of using nanosecond pulsed lasers for micromachining of Si and glass for microelectronics and optoelectronics applications has been performed. Threshold fluence for ablation of Si and glass by nanosecond pulses are proportional to square root of pulse widths. Depth of cut and depth of crators, channels, holes increases with pulse energy, number pulses, frequency of pulses. The diameters of dicing, crators or holes and width of channels are proportional to beam diameter and applied laser fluence. Micromachining experiments with nano pulsed lasers have shown promising results in drilling array of holes, channels, in Glass and Silicon. Publications: 1] Shiva Gadag, F. Ehsan, S. Santhanakrishnan, C. Gilbert, R. Kovacevic, Laser processing of preplaced HAp on EB melted Ti alloy, 28th ICALEO Conference held in Nov. 2-5, 2009, Orlando, FL, USA. 2] Shiva Gadag and Mool Gupta, Laser Synthesis of ZnO Nanostructures, Lasers in Engg.,V17, No. 3-4, pp 239-250 (2007). Introduction: Examples of Micromachined samples by short pulsed Lasers Miniaturization of electronic devices needs new micromachining techniques to machine brittle and transparent materials such as - texturing, micro-milling, drilling, dicing, micro welding and cutting Perform a feasibility study of using nanosecond pulsed lasers for micromachining-Si and Glass for MEMs, Micro-fluidics, Photonics and Optoelectronics device applications Laser power and fluence as function of pulsing frequency 100 Revolutions 1000 Revolutions 2000 Revolutions 4000 Revolutions 8000 Revolutions 10000 Revolutions Laser cutting of Si wafers using IR 1064 95% power Effect of laser rotation on width of Si wafer dicing Laser Micromachining: Si wafers Effect of laser spot diameter on Si Crator Grant No# P200A06216 Grant No#NNX07AB12G Numerical Integration of Energy of net number of pulses residing over beam diameter during laser –materials interaction is used to simulate pulsed laser micromachining Texture=100mm deep Area= 4 sq. mm Micro Texturing of Si : a) 355 nm UV266,P=0.45W,RR=50kHz,Passes=1000; Texuring time =245 s b) 266 nm UV Laser Fractional distance Effective No. Pulses Pulse Overlap Integrated Energy of Moving Pulses Heat Transfer during Nanosecond Pulsed Laser Micromachining: Laser Micro-Milling of Silicon by 532 nm Green Laser B) Glass and Quartz 1 mm Corning Glass Marking/Scribing 1 mm Corning Glass drilling by UV266 P=0.35 W; 3000 pulse/hole P=0.5 W UV266 ; 1000 pulse/hole 2.5 mm Quartz: l=1064nm P=17.3W l=1064 nm P=16.5W; Dia=118 mm l=1064nm; P=16.5–17.5W; V=2mm/s; t =50s Si Ablation Si Crator Si Texturing Si Micro Motor Glass: MicroChannels Laser Micromachining of Silicon and Glass