draft 020210 pw10 picosecond laser...

PicosecondPicosecond laser processing of laser processing of semiconductor and thin film devicessemiconductor and thin film devices

Brian BairdBrian BairdBrian BairdBrian Baird

Summit Photonics LLCSummit Photonics LLC

January 26, January 26, 20102010

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Paper 7580-25, Fiber Lasers VII: Technology, Systems, and Applications, Proceedings of SPIE Vol. 7580, LASE SPIE Photonics West 2010

TopicsTopics

• Introduction and Source Architectures

• Semiconductor Micromachining

• Memory Processing

• Thin Film Device Microprocessing

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• Thin Film Device Microprocessing

• c-Si and Thin Film Solar Cells

• Emerging Technology and Processes

Pulsed Solid State PhotonicsPulsed Solid State PhotonicsEssential Essential MicroelectonicsMicroelectonics ToolsTools

• Pulsed lamp-pumped Nd:YAG lasers entered the trimming and marking laser systems markets in the 1970s.

• Pulsed diode-pumped Nd:YLF lasers entered the commercial systems market in 1988 (Spectra-Physics Model 7950 employed on the ESI Model

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commercial systems market in 1988 (Spectra-Physics Model 7950 employed on the ESI Model 9000)

• In the mid 1990s, 266 nm and 355 nm pulsed harmonic solid state lasers achieved wide adoption.

• Over the past decade, ps DPSS, hybrid, and fiber lasers have begun to enter the industrial laser processing market.

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psps Materials ProcessingMaterials ProcessingA

ve

rag

e P

ow

er

10W

100W

High speed processing –

Micro-via, drilling, dicing,

cutting

Quasi-CW 532nmAnd UV systems-SC Inspection, ,trimming, ...

Trumpf TruMicro –

Coherent Talisker Hybrid

Lumera , TBP, HIQ DPSS

Fianium, IMRAuFibre

SP–PanteraHybrid.

Coherent PaladinDPSS

High speed processing –

Medical, Polymers,

Scribing ....

SeedSources

Bio-

Medical

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Pulse EnergyPulse Energy

Ave

rag

e P

ow

er

100uJ10uJ1uJ100nJ10nJ1nJ 1mJ

1W

0.1W

DPSSFianium -FP1060, FP532Fibre

Ultrafast Ultrafast FiberFiber lasers lasers Comfort Zone NowComfort Zone Now

Fianium -UVP 355Fibre

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Ultrafast Ultrafast ProcessTimescalesProcessTimescales

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psps Solid State PhotonicSolid State PhotonicSource ArchitecturesSource Architectures

• DPSS MOPAs and regenerative amplifiers

• Hybrids (tandem amplifiers) employing fiber front end coupled to solid state

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fiber front end coupled to solid state amplifiers

• All fiber

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Time Bandwidth Time Bandwidth psps DPSS LasersDPSS LasersAmplifier domainlow speed

1 mJ

100 µJ

10 µJ

Pu

lse e

nerg

y

FORTIS™

FUEGO™

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Oscillator domainlow energy

CHEETAH™

1 kHz 10 kHz 100 kHz 1 MHz 10 MHz 100 MHz

Repetition rate

1 µJ

100 nJ

10 nJ

1 nJ

Pu

lse e

nerg

y

ARGOSDUETTO™

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Tandem Amplifier ConceptTandem Amplifier ConceptA Hybrid Approach to Peak Power Scaling A Hybrid Approach to Peak Power Scaling

• Employ DPSS amplifier to boost peak power and output energy per pulse while producing well defined tailored temporal pulse output

• Match gain spectrum of fiber and solid state medium to allow stable harmonic operation

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M-MOFPADPSS Amplifier

Harmonic module

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Tandem Amplifier 32 Experimental Setup

2-Stage, single pass

Nd:YVO4 Amplifier1

MOFPA

M. Frede, Opt. Exp. 15, 459-465 (2007)

MOFPA

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Amplifier ConceptAmplifier ConceptNew: Single or double passLow Input Power Module LP

Standard ModuleMP

New: High Power Module HP

< 100 mW 1-2 W 10-20 W > 50 W

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FI

< 100 mW 1-2 W 10-20 W > 50 W

Flexible power scaling (10-100W) by type and number of modulescw to ps-pulse regimes

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MPMP--Module CW Single Pass ResultsModule CW Single Pass Results

25

30

35

3

4

Nr.of stages:

Ou

tput

Pow

er

[W]

40

50

60

70

Ou

tpu

t P

ow

er

[W]

40

50

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0,0 0,2 0,4 0,6 0,8 1,0 1,2 1,4 1,6 1,8 2,0

0

5

10

15

20

1

2

Ou

tput

Pow

er

[W]

Input Power [W]

0 2 4 6 8 10 12 14 16 18 20

0

10

20

30

40

Ou

tpu

t P

ow

er

[W]

Input Power [W]

0

10

20

30

Ga

in

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Talisker Talisker -- Picosecond Industrial Hybrid LaserPicosecond Industrial Hybrid Laser

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The Promise of AllThe Promise of All--FiberFiber psps LasersLasers

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• Traditional ultrafast lasers have often been bulky, complex and expensive• Benefits of fiber lasers – compactness, reliability, and reduced maintanence• Improvements in DPSS and emergence of fiber lasers enables industrial applications

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Fianium FP1060 Fianium FP1060 psps MOFPAMOFPA

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• Flexible repetition rates

• > 1 MHz for high throughput

• Energy per pulse > 10 uJ

• Excellent beam quality

• Single shot and burst mode for flexibility and control

• Peak powers up to 500 KW4 MW

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TopicsTopics

• Introduction and Source Architectures

• Semiconductor Micromachining

• Memory Processing

• Thin Film Device Microprocessing

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• Thin Film Device Microprocessing

• Processing of c-Si and Thin Film Solar Cells

• Emerging Technology and Processes

psps Scribing Results in UltraScribing Results in Ultra--Low k DevicesLow k Devices

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Very low debris, minimal HAZ, High die fracture strength

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8

10

12

14

16

rem

oval ra

te [m

m³/

min

]

6 Burst

4 Burst

2 Burst

1 Burst

200µm

50µm

Hyper Rapid 50, 1064 nm, constant average power of 50W

Silicon Micromachining – Lumera Hyper-Rapid

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SPIE SPIE 75857585--16 16 MicroMicro-- and Nanomachining , Photonics West 2010and Nanomachining , Photonics West 2010

200 400 600 800 10000

2

4

6

rem

oval ra

te [m

m³/

min

]

repetition rate [kHz]

• High rep. rate + burst: 14x removal rate

Eff. ablation rate:HYPER-RAPID 50 > 20 mm3/min

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Wafer Scribing Wafer Scribing –– FP1060FP1060--HEHE

• 1064 nm• 10 ps• 5 MHz• 600 mm/sec

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• Scribing Low-K region • High repetition rate, low energy – pulse overlap• No Delamination, low debris – very clean scribe

• 600 mm/sec•1.1 uJ

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ps laser Marking of Silicon wafers

Product Tangerine fs Tangerine ps Tangerine sp

Pulse energy > 10 µJ > 10 µJ > 0.5 µJ

Repetition rate

2 MHz 2 MHz 30 MHz

Pulse duration

< 700 fs 10 ps < 100 fs

Footprint (cm)

120x40 120x40 120x40

16x16 DataMatrix

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SEM x385x2540

16x16 DataMatrixmarkingProcessing time 72msDimensions 0.5x0.5mm2µJ @2MHz 100pls/point

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TopicsTopics

• Introduction and Source Architectures

• Semiconductor Micromachining

• Memory Processing

• Thin Film Device Microprocessing

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• Thin Film Device Microprocessing

• c-Si and Thin Film Solar Cells Processing

• Emerging Technology and Processes

Laser Repair System Laser Repair System FabFab InstallationInstallation

~ 100 laser memory repair systems are

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systems are produced and installed annually

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Absorption Contrast is KeyAbsorption Contrast is Key

Professor Schawlow, an early proponent, demonstrates how to employ laser absorption contrast to selectively

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contrast to selectively process a work piece.

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1 1 µµµµµµµµm Compared to 1.3 m Compared to 1.3 µµµµµµµµmmAluminum Links

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1047 nm: Energy level just below damage threshold

1343 nm: Energy level centered in the process

window

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Picosecond pulse and Thresholding

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Thresholding on Si substrate

0.90µJ 0.92µJ 0.94µJ 0.96µJ

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ps Laser Link Processing Results

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57ps IR laser pulse 35ps IR laser pulse

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TopicsTopics

• Introduction and Source Architectures

• Semiconductor Micromachining

• Memory Processing

• Thin Film Device Microprocessing

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• Thin Film Device Microprocessing

• c-Si and Thin Film Solar Cells Processing

• Emerging Technology and Processes

Thin film removal for Flat Panel Displays532nm

• Patterning of ITO on SiN for flat panel displays.

• 532nm, 5µJ, 200kHz, scan speed =3m/s.

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TopicsTopics

• Introduction and Source Architectures

• Semiconductor Micromachining

• Memory Processing

• Thin Film Device Microprocessing

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• Thin Film Device Microprocessing

• c-Si and Thin Film Solar Cells Processing

• Emerging Technology and Processes

Comparison of ns and Comparison of ns and psps Edge Isolation Edge Isolation laser processinglaser processing

ns-system ps-system

≤16kΩcm² ≥24kΩcm²

Thermal regime Optical regime

6.6kΩcm²

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•Results:

•higher shunt resistances

•1 s laser processing time

•less damages

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psps Edge Edge Isolation of cIsolation of c--Si PV cellsSi PV cells

0,2

0,3

0,4

thermal penetration zone

0.2

0.3

Av.

ab

latio

n d

ep

th p

er

pu

lse

aP (

µm

/pu

lse

)TruMicro 5050

λ = 515 nm

τP = 7.3 ps

fP = 100kHz

0.4

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0,1 1 10

0,0

0,1

1010.1

0.0

0.1

Av.

ab

latio

n d

ep

th p

er

pu

lse

a

Laser fluence HP (J/cm

2)

optical penetration zone

Htrans

= 1 to 1.1 J/cm2

Typical ablation behaviour for a ps-laser

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532 nm 532 nm psps MOFPA ablation of MOFPA ablation of SiNSiN on con c--SiSi

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Speed: 4000 mm/sAblation threshold ~0.1 J/cm2

Goal: Remove SiN to produce metallization “streets”

532nm

Thin film removal – solar cells

355nmFluence ~0.11 J/cm2

(~1.5 times laser ablation threshold)

532nmFluence ~0.27 J/cm2

(~2 times laser ablation threshold)

355nm

• Selective removal of SiO2 from silicon.

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• No melt visible when using 355nm close to the laser ablation threshold.

• Some melt is visible on the silicon when using 532nm (note higher fluence).

SEM images courtesy of Nanogram

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Monolithic interconnection in CIGS solar modules

ZnO:Al Front contact

deposition by

sputtering

Mo back contact

deposition by sputtering

Scribing of Mo

by laser beam

CIGS absorber deposition

by vacuum evaporation

CdS or ZnS buffer

deposition

by chemical method

Patterning of buffer/CIGS

by laser scribing

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ZnO:Al (1 µm)

CdS or Zns (0.03 µm)

CIGS (2 µm)Mo (1 µm)

Substrate

Patterning of front contact

& wiring

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CIS P1 CIS P1 by by psps ablationablation, low overlap, low overlap

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• Ps-front side and ps back side ablation

• Process speed of 2 to 20 m/s possible

• Galvanic separation perfect

• Groove width of ca. 30 µm, depth 400 nm

• No damage on the ablation ground barrier layer functional

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CIS P3 CIS P3 by by psps ablationablation

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• Process speed 2 m/s possible

• Groove depth of 3.6 µm Complete separation of the ZnO-CIS-film.

• ZnO-layer (green) is chipped-off without thermal influence and micro cracks,

CIS-film (turquoise) exhibits faint rims on both sides of the groove, Mo-

surface (blue) is free of CIS

• Functionality has still to be validated

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Laser Shipment Projections for Thin Film Scribers Laser Shipment Projections for Thin Film Scribers

3000

4000

5000

6000L

asers

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0

1000

2000

2008 2009 2010 2011 2012 2013 2014 2015

Lasers

Year

Key Assumption: 0.25 Lasers/MW

TopicsTopics

• Introduction and Source Architectures

• Semiconductor Micromachining

• Memory Processing

• Thin Film Device Microprocessing

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• Thin Film Device Microprocessing

• c-Si and Thin Film Solar Cells Processing

• Emerging Technology and Processes

Laser Processing of Nontransparent MaterialsLaser Processing of Nontransparent Materials

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Laser Processing of Nontransparent MaterialsLaser Processing of Nontransparent Materials

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Optical Optical HyperdopingHyperdopingResponsivityResponsivity

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LIPSS Processing of Stainless SteelLIPSS Processing of Stainless Steel

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Silicon scribing and LIPSS texturing

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11 µm width groove – depth 6µm

Single Groove

6,5µm deep

Parrallelgrooves

Crossed

grooves

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Silicon Texturing (black silicon)

Flexible Flexible PulsewidthPulsewidth psps fiberfiber oscillatoroscillator

Narrow spectrum: < 1 nm

Linearly polarized

1064 nm central wavelength

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Adjustable pulse duration: 30 ps < ττττ < 300 ps

Repetition rate: > 5 MHz

Oscillator output pulse energy: 1-10 nJ.

US Patent application No 12/498,072

Amplification Amplification limitslimits of of psps pulses in pulses in silicasilica fibersfibers @ 1064 nm@ 1064 nm

SRS Maximum peak power SPM Spectral broadening

15

20

Am

plit

ude

nois

e (

± %

)

Amplitude noise on the optical pulses as a function of their peakpower normalized to the effective area of the amplifying fiber

140 ps

70 ps

35 ps

2

3.5

4

4.5

5

sp

ectr

al w

idth

FW

HM

(n

m)

Spectral broadening of the pulse as a function of their peakpower normalized to the effective area of the fiber

140 ps

70 ps

35 ps

S4444

0 10 20 30 40 50 60 700

5

10

Normalized peak power (kW / 100 µm2)

Am

plit

ude

nois

e (

± %

)

40 kW / 100 µm2 of effective area

0 10 20 30 40 50 60 70 800

0.5

1

1.5

2

2.5

3

Normalized peak power (kW / 100 µm2)

sp

ectr

al w

idth

FW

HM

(n

m)

[ ][ ]

[ ] [ ]2300

mApst

kWPnm

effFWHM

peak

FWHMµ

λ∆

≈∆

Summit is a provider of Summit is a provider of Photonics Engineering Services Photonics Engineering Services

• Founded June, 2008

• Office and lab facility in Portland metro area

• Laser processing system architecture design and system selection and evaluation

• Laser source evaluation, design, and selection

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• Laser source evaluation, design, and selection

• Advanced laser process development and evaluations

• Photonics intellectual property evaluation and creation– IP rights assignment

• Photonics “gap” engineering solutions

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Summit Laser Application LabSummit Laser Application Lab

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Summary and OutlookSummary and Outlook

• Industrial picosecond laser processes are being

adopted for semiconductor and solar cell

manufacturing.

• LIPSS applications represent an important area

of research and emerging industrial applications.

• High pulse energy applications will continue to

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• High pulse energy applications will continue to

be dominated by ps laser solutions employing

solid state power amplifiers.

• All fiber ps lasers will compete successfully in the

thin film (PV and display) and semiconductor IC

markets.

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AcknowledgementsAcknowledgements• Bob Hainsey (ESI)

• Sean Peng (ESI)

• Jeff Albelo (ESI)

• Joohan Lee (GSI)

• Kurt Weingarten (TBP)

• Mark Keirstead (Coherent)

• Pascal Deladurantaye (INO)

• Yves Taillon (INO)

• Maik Frede (LZH)

• Dietmar Kracht (LZH)

• Viktor Schuetz (LZH)

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• Mark Keirstead (Coherent)

• Colin Moorhouse (Coherent)

• Robert Braunschweig (A-S)

• John Clowes (Fianium)

• Heinz Huber (HiQ)

• Uwe Stute (Trumpf)

• Peter Herman (U. Toronto)

• Ralf Knappe (Lumera)

• Dirk Muller (Lumera)

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Thank You!

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Questions?

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