Laser drilling of a Copper Mesh Vincenzo Berardi U.O.S. Bari, Italy - - PowerPoint PPT Presentation

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Laser drilling of a Copper Mesh Vincenzo Berardi U.O.S. Bari, Italy - - PowerPoint PPT Presentation

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7th RD51 Collaboration Meeting 13-15 April 2011 - CERN Laser drilling of a Copper Mesh Vincenzo Berardi U.O.S. Bari, Italy Dip. Interuniversitario di Fisica M. Merlin Laser Ablation Definition Laser ablation is the process of removing

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SLIDE 1

Laser drilling of a Copper Mesh

Vincenzo Berardi

7th RD51 Collaboration Meeting 13-15 April 2011 - CERN

U.O.S. Bari, Italy

  • Dip. Interuniversitario di Fisica

“M. Merlin”

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SLIDE 2

Laser Ablation Definition

Laser ablation is the process of removing material from a solid surface by irradiating it with a laser beam. At low laser flux, the material is heated by the absorbed laser energy and evaporates or sublimates. At high laser flux, the material is typically converted to a plasma. Usually, laser ablation refers to removing material with a pulsed laser

Vincenzo Berardi - 14 April 2011 CERN – 7° RD51 Collaboration Meeting

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SLIDE 3

Timescales of the laser ablation process

Mazur et al. Nature Materials 2, 217 (2002) fs ps ns µs

energy absorption by free electons electron - lattice energy transfer ablation by phase explosion or evaporation Thermal diffusion Melting and resolidification

Vincenzo Berardi - 14 April 2011 CERN – 7° RD51 Collaboration Meeting

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SLIDE 4

Laser drilling strategies for high accuracy

Trepanning optic for helical drilling

  • F. Dausinger et al., Springer (2004)

Vincenzo Berardi - 14 April 2011 CERN – 7° RD51 Collaboration Meeting

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SLIDE 5

Cu Parameters

Material Density (g cm-3) Thermal Conductivity (W m-1 K-1) Melting point (°C) Vaporization temperature (°C) Copper Metal 8.94 400 1084 2562

  • Finding optimal laser process parameters

(pulse duration, wavelength, fluence, drilling strategy)

  • Copper oxide around the hole walls

(post process cleaning could be required) Advantages Flexible technology: complete control of the hole morphology (taper, diameter) and geometry (density of the holes mm-2, distribution)

Vincenzo Berardi - 14 April 2011 CERN – 7° RD51 Collaboration Meeting

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SLIDE 6

Microchip laser fiber amplifier (100 ps)

mm mm

Pump diode

0.55 m PM-DC 1.5 m PM-PCF 18 Watt 5 Watt

Yb-doped photonic crystal fiber

fiber coupled diode laser, 808nm, 1W dichroic mirror, HR @ 1064nm, AR @ 808nm f=30mm f=20mm coating, laser crystal, SESAM Q-switched output spin on glass glue

Quasi-monolithic Q-switched microchip laser

Vincenzo Berardi - 14 April 2011 CERN – 7° RD51 Collaboration Meeting

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SLIDE 7

CNR-IFN Bari - Laser materials processing lab

Short pulse 100 ps fiber laser

Specifications

Wavelength 1064 nm Pulse duration 100 ps Repetition rate ≈ 100 kHz Pulse energy max. 100 μJ Average power 10 W Peak power max. 1 MW Collaboration CNR-IFN Bari FSU JENA

Vincenzo Berardi - 14 April 2011 CERN – 7° RD51 Collaboration Meeting

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SLIDE 8

Post process Analysis

  • Electron Microscopy - Field Emission
  • EDS (EDX) (Energy Dispersive X-ray Spectroscopy)

Vincenzo Berardi - 14 April 2011 CERN – 7° RD51 Collaboration Meeting

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SLIDE 9

A look at the surface(s)

Vincenzo Berardi - 14 April 2011 CERN – 7° RD51 Collaboration Meeting 5mm layer front surface 5 mm layer back surface

5mm 18mm

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SLIDE 10

Vincenzo Berardi - 14 April 2011 CERN – 7° RD51 Collaboration Meeting

EDS

Metallic surface

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SLIDE 11

Single layer drilling

Vincenzo Berardi - 14 April 2011 CERN – 7° RD51 Collaboration Meeting

5mm 18mm

Array of 400 x 400 holes 1cm x 1 cm (post processing 20 x 20) Average Pitch (center to center) d = 24mm Average size (diameter) = 13 mm Laser Power = 500mW Overall processing time = 2 hours and 30 mins

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SLIDE 12

Single layer drilling

Vincenzo Berardi - 14 April 2011 CERN – 7° RD51 Collaboration Meeting

#8_02Mar_5up_laser_entry01 #8_02Mar_5up_laser_entry02 #8_02Mar_5up_laser_entry03 #8_02Mar_5up_laser_entry04

Diameter (mm) Pitch (mm) 5mm layer 13.10 (0.8) 24.50 (1) 18 mm layer 7.50 (0.8) 23.55 (1)

5mm 18mm

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SLIDE 13

Vincenzo Berardi - 14 April 2011 CERN – 7° RD51 Collaboration Meeting

Double layer drilling

5mm 18mm 1 2 3 4 5mm 18mm #9_02Mar_5up_laser_entry01 #9_02Mar_5up_laser_entry02 #9_02Mar_5up_laser_entry03 #9_02Mar_5down_laser_exit01

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SLIDE 14

Vincenzo Berardi - 14 April 2011 CERN – 7° RD51 Collaboration Meeting

Double layer drilling

#9_02Mar_5down_laser_exit02 #9_02Mar_5down_laser_exit03 #9_02Mar_5down_laser_exit04 #9_02Mar_5down_laser_exit05 5mm 18mm 1 2 3 4 5mm 18mm

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SLIDE 15

Vincenzo Berardi - 14 April 2011 CERN – 7° RD51 Collaboration Meeting

EDS

Hole edge Between holes

5mm 18mm

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SLIDE 16

Vincenzo Berardi - 14 April 2011 CERN – 7° RD51 Collaboration Meeting

EDS

Near Hole edge

5mm 18mm

Hole edge

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SLIDE 17

Summary

Vincenzo Berardi - 14 April 2011 CERN – 7° RD51 Collaboration Meeting

 Cu meshes can be drilled to obtain 12-14 micron diameter holes with a pitch of 20-25 microns (focusing spot down to < 10 μm)  Only percussion drilling can be reliably used and Oxide formation can be limited but not avoided by flowing inert gas on the surface.  Contamination can be reduced by changing the geometry as follows

5mm 18mm 18mm

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SLIDE 18

IFN Group

Antonio Ancona CNR-IFN, Staff Teresa Sibillano CNR-IFN, Staff Francesca Di Niso Dept of Physics, PhD student

Vincenzo Berardi - 14 April 2011 CERN – 7° RD51 Collaboration Meeting

INFNGroup

Gabriella Catanesi INFN, Staff Vincenzo Berardi Dept of Physics, Staff Emilio Radicioni INFN, Staff