Femtosecond laser micromachining system

Information in this document is confidential and can be disclosed only with approval of Altechna R&D Ltd.

Workshop of Photonics – a registered trademark of Altechna R&D Mokslininkų 6A, LT-08412, Vilnius, Lithuania, tel.: 370-5-2725738, fax.: 370-5-2723704, e-mail: [email protected], www.wophotonics.com

System Features

- Femtosecond laser with 1028 nm, 514 nm

wavelength

- High accuracy sample positioning

- Machine vision

- Control of entire system through single-window GUI

software

- Laboratory design - easily extendable system,

custom design

- 1 year warranty (extendable)

Applications

- Micro-cutting, drilling, marking

- Surface micro- and nano-structuring

- Waveguide fabrication

- Multi photon polymerization

FemtoLAB Femtosecond laser

micromachining system

femtoLAB initial design



Figure 1 femtoLAB SZU principal scheme. Final optical configuration might differ.

Motorized attenuators (MA)

SHG 514 nm

280 fs 200 kHz

PHAROS laser control

Granite Base with bridge

XYZ1Z2 4 axis Aerotech

positioning system

CCD

LED

Harmonics generator SH and FH

PHAROS Femtosecond laser 1028 nm 10 W <300 fs 200 kHz

MA1 MA2

SLM

X y

Z1

PR2

PR1 Motorized polarization

rotators (PR)

Z2

1028 nm 280 fs

200 kHz

Principal optical system scheme



System components specifications

Feature Specifications Value Unit

Femtosecond laser source Pharos

Wavelength

1028 nm

Average power 10 W (at 1028 nm)

Repetition rate (tunable) 1 kHz – 1 MHz

Pulse duration (tunable) 290 fs – 10 ps

Pulse energy (tunable) max. 200 μJ

Beam quality M2 <1.2

Beam diameter (FWHM) 3 ±1 mm

Beam divergence 1.1x diffraction limited

Polarization (switchable) Linear, horizontal

Beam pointing stability < 20 μrad/°C

Pulse picker Included

Cooling Water cooled

Industrial harmonic generator (IHG)

Generated harmonics

SHG

514 nm

Conversion efficiency >50 % @514 nm

Beam quality M2 < 1.3 @514 nm

Changing harmonics motorized

IHG module is mounted directly on the output of the laser and integrated into the system.

External power control 2 pcs

Motorized Yes Power control 0 – 100 % Wavelength 1028

514 nm nm

Automated power calibration

Yes

Time dispersion t<4 fs for 100 fs

XYZ1Z2 positioning system 4 axis positioning stages



sketch drawings

Total travel XYZ1Z2

200 x 100 x 5 + 50 mm

XY axis Air bearings Accuracy XY ±400 nm Accuracy Z1 (5 mm travel) ±1.5 μm Accuracy Z2 (50 mm travel) ±2.5 μm Vertical load Z2 10 kg Resolution XY 5 nm Minimum controllable displacement XYZ1

50 nm

Max speed XY 500 mm/s Max speed Z1 4 mm/s Max Acceleration XY 0.5 G Max. Load. 5 kg Repeatability XY ±100 nm XYZ orthogonality 10 arc sec Mounted on granite base Yes Position synchronized output (PSO)

Spatial light modulator (SLM)

Matrix size

SXGA (1280 x 1024 pixels)

Operating wavelength 510 ± 50 nm Number of input levels 256 (8 bits) levels Effective area 16 mm x 12.8 mm Spatial resolution max. 25 lp/mm Light utilization efficiency 98 %

Polarization rotation 2 pcs

Motorized

Yes

Wavelengths 1028 nm, 514 nm Half Waveplates ZO λ/2 Material crystalline quartz

Beam delivery optics

Dielectric mirror HR 45 deg

R >99.5%

Wavelenghts 1028 nm, 514 nm

No dispersion Wavefront distortion λ/8 Clear paperture 25 mm Mounted in standard two-adjuster kinematic mirror mounts

Focusing optics for 1028 nm & 514 nm 5 pcs

Magnification

10X

20X

50X

100X

63X



Numerical aperture 0.28 0.29 0.42 0.7 1.4

Working distance, mm 34 31 17 6 0.1

Operating wavelength

1028 nm + + +

514 nm + + + + +

Resolution 4 μm 2 μm 1 μm 0.5 μm 0.3 μm

Immersion oil no no no no yes

Machine vision 1 pcs

Operating wavelength

590 nm

CMOS matrix size 1280x1024 Resolution (on axis camera) >1 μm* Speed (GigE interface) 15 fps Live fabrication preview (with on axis camera) Advanced find focus algorithms Superposition with fabrication algorithm preview * depend on objective used

Power meters 1 pcs

Power measuring heads

6 W

Aperture 12 mm Spectral range 0.19 – 20 μm Auto calibration yes Beam power real-time read out by SCA software

Safety goggles 1 pcs

Color

Amber

Optical Density 5+ (190-534 nm); 5+ (730-1090 nm);

7+ (1064 nm)

Visible Light Transmission 10.6 %

Debris removal exhaust system 1 pcs

Air flow

190 m3/h

Filters dedicated for laser fume and dust:

• Resublimation filter / spark protection

• Submicron particulate filter

• Activated carbon filter

SCA Software

Controls all system devices



Laser firing Laser power Pulse repetition rate Power attenuation with motorized attenuator Automatic and manual positioning stage control Beam power real-time read out by software DXF, STL, PLT, BMP, TXT file import Polylines blending and transformation



Additional system configuration information

System is equipped with industrial computer with Microsoft Windows operating system. Minor

components and exact configuration is determined during system design stage. Set of spare optical

components (mirrors, beam splitters, polarizers) is included in system price.

Delivery Terms

Assembly of the whole system will take 5-7 months after confirmation of purchase order. System will

be assembled and tuned in Lithuania by Altechna R&D or its subcontractors. Final system commissioning

will take place in at customer site. Customer is responsible for preparation of installation premises.

Laboratory requirements:

• Temperature 21 ±2˚C

• Humidity 40 ±10% (more stable the better)

• Power supply 220 VAC, 10 A

• Clean room at least ISO 8 (ISO 14644-1 cleanroom standards)

Maintenance Terms

All technical issues during the warranty period, arising from proper use of the system should be

solved by Altechna R&D or its subcontractors.

Any technical issue should be discussed through Skype or phone and effort should be made from

both sides to solve the problem in a distance through consultations.

If remote solving of the problem fails, an engineer from Altechna R&D or its subcontractors should

visit the site in less than four weeks to solve the problem;

Warranty

The key components of the system bear one year of warranty. Laser beam delivery, focusing and

harmonic generator optics shall be treated as consumables, therefore only limited installation warranty is

valid for two weeks after installation.



Micromachining examples with FemtoLAB

Images provided below are made using different photo techniques: optical microscope, SEM, white

light surface profilometer. Samples there processed with different femtoLAB configurations: different

harmonics, beam shaping units, focusing objectives.

Figure 2 Optical microscope photo of olivine sample surface before experiment. Few testing cuts on the smallest piece of the shattered sample are visible (left). Pattern designed for complex shape of the sample, optimized to get maximum number of discs from available cutting area (center). Final sample prepared according to scan trajectories. Some parts of the sample seem to have less debris, indicating weaker or no damage to crystal bond – thickness variations. No cleaning after laser processing.

Figure 3 Optical microscope photos of circle grooves ablated on olivine surface. Circle grooves diameter from 35 μm to 150 μm, depth 7 – 10 μm (left). Example of bottom of grooves (40 μm diameter discs) ablated by multiple passes. Depth of grooves up to ~25 μm (wavelength and pulse duration confidential).



Figure 4 SEM photo of silicon (Si) surface back contact formation for photovoltaics (ʎ = 343 nm, τ = 300 fs).

Figure 5 BST ceramics grooves ablation. Optical microscope photo (left) and SEM image of lines crossing

(wavelength and pulse duration confidential).

Figure 6 Optical microscope photo of a 5 μm diameter hole drilled in glass tube (wavelength and pulse

duration confidential).



.

Figure 7 Optical microscope photos of tapper less hole drilling in stainless steel alloy. Process requires

special beam shifter unit (ʎ = 1030 nm, τ = 300 fs).

Figure 8 Front surface (left) and back side optical microscope photos of 200 μm thickness PLLA polymer cutting (ʎ = 343 nm, τ = 300 fs).



Figure 9 Optical microscope photos of various diameter holes drilled in optical fiber (left). Dark field

photo of 10 μm diameter hole drilled in fiber up to the core (ʎ = 1030 nm, τ = 300 fs).

Figure 10 Optical microscope (left) and SEM photo of micro- lens fabricated on the tip of the fiber using multiphoton polymerization technique (ʎ = 515 nm, τ = 300 fs).



Figure 11 Photo of Lithuanian scientist fabricated on the surface of 50 mm diameter dielectric mirror (left). Optical microscope photo of ≈15 μm pixels (ʎ = 1030 nm, τ = 300 fs).

Figure 12 Photo of surface acoustic wave transducers fabricated on YZ-LiNbO3 by selectively ablating thin chromium layer (left). Optical microscope (front illumination) photo of transducer (ʎ = 1030 nm, τ = 300 fs).

Figure 13 optical microscope photos of ceramic and PET sandiwtch drilling (ʎ = 515 nm, τ = 300 fs).



Figure 14 Optical microscope photos of holes drilled and line scribed in 250 μm thickness AlN substrate (ʎ = 343 nm, τ = 180 fs).

Figure 15 Optical photos of brass micro-marking (ʎ = 1030 nm, τ = 300 fs).

Figure 16 Optical mcroscope photos of 50 μm diameter holes drilled in non-tempered 320 T glass 320 μm thickness substrate (ʎ = 343 nm, τ = 300 fs).



Figure 17 Optical microscope photos of silicon nitride (SiN) dielectric layer selective ablation from silicon (Si) substrate. Special beam shaping unit is required for this process (ʎ = 1030 nm, τ = 10 ps).

Figure 18 SEM images of nanoriples fabricated on surface of sapphire (ʎ = 1030 nm, τ = 300 fs).

Figure 19 Optical microscope photos of hex pattern ablated on glass surface. Line width 10 μm (ʎ = 515 nm, τ = 300 fs).



Figure 20 SEM images of 3D photonic crystals fabricated using multi photon polymerization techniques (ʎ = 515 nm, τ = 300 fs).

Figure 21 SEM images of various 3D elements grating (left) and axicon fabricated using multi photon polymerization technique (ʎ = 515 nm, τ = 300 fs).

Figure 22 SEM images of various 3D elements birpism and lens with grating fabricated using multi photon polymerization technique (ʎ = 515 nm, τ = 300 fs).



Figure 23 SEM images of scaffolds (large 2 mm x 2 mm structure (left)) and single 3D HEX cells fabricated using multi photon polymerization technique in special polymer (ʎ = 515 nm, τ = 300 fs).

Figure 24 Optical microscope photo of grooves ablated on sintered silicon carbide surafe (left) and ablated groove surface (ʎ = 343 nm, τ = 300 fs).

Figure 25 White light profilometer image of dots array fabricated on glass surface (left) and single dot profile

(ʎ = 1030 nm, τ = 300 fs).



Figure 26 SEM image (left) of 3 μm diameter micro-channel fabricated on soda lime glass surface and it‘s profile measured with white light profilometer (ʎ = 343 nm, τ = 300 fs).

Figure 27 SEM images of cutting 10 μm thickness copper layer on printed circuit board. Top view (left) and 60 deg tilted view on the right (ʎ = 1030 nm, τ = 300 fs).

Femtosecond laser micromachining system

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