1. 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 (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 % 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