PracticalPractical ApplicationsApplications ofof LaserLaser TechnologyTechnology forfor SemiconductorSemiconductor ElectronicsElectronics MOPA Single Pass Nanosecond Laser Applications for Semiconductor / Solar / MEMS & General Manufacturing
Mark Brodsky US Application Laboratory Manager Overview
● General Industrial Laser Overview ● Sources and variables ● MOPA vs Q-Switch Lasers ● Typical laser uses for Electronics ● Gaussian vs Single Pass Pulses ● Benefits of High kHz and Peak power ● Application Examples
Not to be distributed without prior consent of SPI Lasers Wide Spectrum-Rules of Thumb
1.064 is industrial starting place for smaller but powerful spots Cut wavelength in half at Triple the price and less power Less absorption depth comes at a price of thermal stability
Not to be distributed without prior consent of SPI Lasers Lasers in Electronics
● MicroMachining ● A range of infra red, visible and ultra violet laser sources give fast machining of a wide range of materials
● Via Drilling ● CO2 Laser drilling machine: Package, Printed circuit board, Ceramic device Material: Glass-epoxy, Epoxy, Green sheet) ● UV Laser drilling machine: Package, Printed circuit board, Flexible board material: Glass-epoxy, Epoxy, Polymide)
● Stencil Cutting ● CO2 Laser drilling machine: Package, Printed circuit board, Ceramic device Material: Glass-epoxy, Epoxy, Green sheet) ● UV Laser drilling machine: Package, Printed circuit board, Flexible board material: Glass-epoxy, Epoxy, Polymide)
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● Plastic ● Ceramic ● Through Plating ● Strip / Remark
Not to be distributed without prior consent of SPI Lasers Nanosecond Lasers
● Predominantly solid state 1micron sources
●Rod - Nd:YAG, YVO 4
●Disk – Yb+:YAG
●Fiber - Yb+
Not to be distributed without prior consent of SPI Lasers Pulsed MOPA Fiber Laser
Amplifier Chain (GTWave Technology) directly modulated LD
Seed Pre-Amp Post-Amp Laser
Advantages of MOPA architecture: Pulse parameters can be controlled independently at different stages
Extensive pulse energy and peak power parameter space
Not to be distributed without prior consent of SPI Lasers MOPA Laser Technical Description
Seed Optical Yb GTWave TM Yb GTWave TM Fibre Optic Output Pulses Pulses Pre-Amplifier Power-Amplifier Beam Delivery
Seed Laser Diode Pump Laser Diode Pump Laser Diodes
Seed Laser Driver Pump Laser Driver Pump Laser Driver
Main Control and Monitoring Electronics
User Control Electronics
• MOPA architecture • optical seed pulse generated by a single-mode semi-conductor (master-oscillator) laser diode • dual-stage Yb GTWaveTM fibre amplifier system pumped by multi-mode 9xx nm laser diodes • fibre-optic beam delivery cable terminated with collimator, optical isolator and optional telescopes
Not to be distributed without prior consent of SPI Lasers SPI’s PulseTune Optical Pulses
Directly ModulatedNew Waveforms 20W @ 20W Q-Switched Fiber laser @ 20W
16.0 16 25 kHz 15 14.0 14 20 kHz 13 30 kHz 12.0 12 40 kHz 60 kHz 11 80 lHz 10.0 10 9 20 kHz 8.0 8 80 kHz
Power (kW) Power 7 6.0 6 peak powerpeak (kW) 5 4.0 4 3 2.0 2 80 kHz 1 0.0 0 -50 0 50 100 150 200 250 300 0 50 100 150 200 250 300 350 Time (s) time (ns) Increasing rep rate by using different Increased rep rate Wave Forms with shorter pulse significantly reduces peak lengths limits peak power reduction power
Not to be distributed without prior consent of SPI Lasers Marking Optics – Galvo Systems Mirror(2) Beam Aperture Expander Scan Head
Pupil Spacer iBDO Spacer F-Theta Lens Spot Size Marking Plane
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● Equals High Speed Processing
Not to be distributed without prior consent of SPI Lasers Spot Overlap: Marking quality up-close (one of several quality measures) Half the story!
No Spot Overlap Spot overlap is a key • visible mark • poor resolution ● Greater overlap produces a more continuous mark appearance • dotted-line ● >60% overlap desired for many marking applications
To increase spot overlap <5% Spot Overlap ● Slow down the mark until the • improved mark pulses overlap • low resolution • “scallop” edge Or (better put)
● Increase the pulse repetition rate at your desired marking speed ! >60% Spot Overlap • desired mark • high resolution • smooth line edge
Not to be distributed without prior consent of SPI Lasers Higher KHz provides smoother ablation
●Spot overlaps only works when transition energy is has been passed.
●Less ablation, more material conversion
Not to be distributed without prior consent of SPI Lasers Solar Energy/Display Technology ● Scribing Transmissive Conducting Oxide (TCO) ● Typically Indium Tin Oxide (ITO) ● Careful control of the pulse energy is crucial to; ● completely remove the film, ● produce minimal burr to the patterned edge, ● lack of cracking/delamination of the TCO ● no damage to the glass substrate.
20W; 25kHz WF0 20W; 125kHz WF2 1m/s scan speed 1m/s scan speed 80 m scribe width 40 m scribe width
Not to be distributed without prior consent of SPI Lasers Different Beam Quality & Pulse Energy The right tool for every job!
Series SM RM/HS HM
M2 <1.3 <2 ~3.2
Power 10W / 20W 10W / 12W / 20W 30W / 40W Key attribute Fine feature Multi purpose Wider lines <25micron 35-80micron >60micron
Application Scribing (P1) General marking and Wide marks deep Fine marking micro-machining engrave area/logo
Not to be distributed without prior consent of SPI Lasers Comparison of M 2 on Application
● What is best for Snap and break in ceramic 20W SM 1.1 20W HS 1.8 40W HM 3.2
Pulse with smallest M 2 has highest power density but may not be best for the application!
Not to be distributed without prior consent of SPI Lasers Flexible Tool - Diverse Applications
Images and samples courtesy of: Miyachi Unitek, Electrox, LMCo & Orotig Silicon Processing
● Scribing and Cutting ● Low rep rate 25kHz ● Deep scribe ● High level of debris ● High rep rate >100kHz ● Shallow scribe ● Low level of debris ● Drilling ● Similar effect to above ● >400holes/s in 200µm Si wafers with 20W laser ● Diameter circa 50 µm ● Marking ● Can be smooth on surface ● But no circuitry can be below
Not to be distributed without prior consent of SPI Lasers Molybdenum thin film ablation
● P1 scribe ● Electrically conducting back contact film for CIGS or CIS modules ● 0.25-1 µm thick ● 125kHz, 4 m/s ● 30-40µm wide lines on 0.2 mm pitch
Not to be distributed without prior consent of SPI Lasers Enhanced Ohmic conduction ● Annealing of thin metallic film ● Array or overlapping spot fill techniques ● Enhanced contact with underlying layer ● Control of pulse to minimise damage
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Difficult to process TG ~3000°C ns Pulsed fiber laser 20W HS Good solution for micromachining
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Fired and Green Ceramic
Half mm Copper Heat
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● Cutting ● Drilling ● Mould cleaning ● Micro-machining
Not to be distributed without prior consent of SPI Lasers LaserLaser ProcessingProcessing ApplicationsApplications
The majority of laser materials processing applications are impacted by: Peak pulse power which is typically required to overcome processing thresholds. kW Pulse energy which governs the amount of thermal energy available to effect any material processing. mJ Pulse duration impacts beam material interaction time. ns Power Density – which reflects the intensity of the laser energy on the substrate. W/mm2 Average Power – typically governs productivity and processing speed W Pulse M 2 – Spike, Hammer, or “Hoss” Hat
It is often a combination of these parameters that needs to be considered in pulsed laser materials processing applications. Conclusions ● MOPA ns pulsed fiber lasers offer: ● Front end loaded pulse energy ● High peak power - High kHz processing for speed ● Expanding application space
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