laser micro machining materials

8/8/2019 Laser Micro Machining Materials

1/13

Potomac Photonics Inc.

4445 Nicole Drive

Lanham, MD 20706

ISO 9001:2008

ISO 13485

Laser Micromachining Notes

Materials

Mike Adelstein

[email protected](301)459-3031

Potomac is your Micro Manufacturing

leader from prototypes to production.

Contact us today.


2/13


4445 Nicole Drive

Lanham, MD 20706

ISO 9001:2008

ISO 13485

2

Experts in Miniaturization

Microfabrication of features as small as 1-2 micronsProcess almost any material, including polymers, glass, ceramics

and metals

Applications include: holes, channels, cutting, and marking on bothflat and conformal surfaces.

New, advanced capability: revolutionary laser process developed atPotomac allows for deposition of materials such as silver on

polyimide.

Major industries served include: medical devices, biotechnology,and electronics.

Laser Deposition: part of a bandpass

filter. Silver deposited on Kapton

Laser cut stent from stainless

steel

Holes in Polyurethane

tubingMicromachining www.potomac-laser.com


3/13


4445 Nicole Drive

Lanham, MD 20706

ISO 9001:2008

ISO 13485

Polymer spectra

ArF KrF

101.10.0

0.2

0.4

0.6

0.8

1.0

Wavelength (m)

Transmission

3mm thickness

Nd:YLF

Polycarbonate

Polyimide

Polystyrene

Acrylic

Micromachining www.potomac-laser.com


4/13


4445 Nicole Drive

Lanham, MD 20706

ISO 9001:2008

ISO 13485

Strong and weak

absorbers

0.50.40.30.20.1

.01

.1

1

10

100

1000

Wavelength(m)

Absorptiondepth(m)

ArF KrF

PMMA

Polyimide



5/13


4445 Nicole Drive

Lanham, MD 20706

ISO 9001:2008

ISO 13485

Metal spectra

Excimer YAGCO2



6/13


4445 Nicole Drive

Lanham, MD 20706

ISO 9001:2008

ISO 13485

Crystal/glass spectra

101.1

0.0

0.2

0.4

0.6

0.8

1.0

Sapphire

Fused Silica

PyrexMgF2

1 mm thickness

Wavelength (m)

Transmission

ArF KrF Nd:YLF



7/13


4445 Nicole Drive

Lanham, MD 20706

ISO 9001:2008

ISO 13485

Ablation energy

Modestlaser

energy forsmall

features

Ceramic or metal ablation

Polymer ablation

100101

.01

.1

1

10

100

Focal Spot Diameter (m)

Fluence(J/cm2

)

100 nJ

1 J

10 J

100 J



8/13


4445 Nicole Drive

Lanham, MD 20706

ISO 9001:2008

ISO 13485

Pulse duration and the HAZ

Largest HAZ in goodthermal conductors

Short laser pulsesminimize HAZ

Heat conduction distance = (Thermal diffusivity x time)1/2

QS YAGExcimer

1000100101.1.01.001.01

.1

1

10

100

1000

10000

Aluminum

Stainless Steel

Al2O3

Glass

Polyimide

Time (s)

ThermalDiffusionDis

tance(m)

Pulse YAG Mod CO2



9/13


4445 Nicole Drive

Lanham, MD 20706

ISO 9001:2008

ISO 13485

Single pulse ablation depth

Material Depth/pulse

Polymers 0.3 - 0.7 mCeramics & Glass 0.1 - 0.2 m

Diamond .05 - .1 m

Metals 0.1 - 0.2 mAblationdepth

Conditions:

Fluence - 2 to 10 J/cm2

Strong optical absorption

Pulse duration - 10 - 50 ns



10/13


4445 Nicole Drive

Lanham, MD 20706

ISO 9001:2008

ISO 13485

Focusing on repeatability

Feature sizechanges with

surface height

Largest effect withhigh N.A. optics

Implications: Fixturing Substrate

uniformity

Focus monitor

Largerdiameter

Smallerdiameter



11/13


4445 Nicole Drive

Lanham, MD 20706

ISO 9001:2008

ISO 13485

Light absorption by

polymers

UV1. Light excites bound

electrons

2. Some bonds break

3. Some electron energyconverted to molecular

vibrations (heat)

IR1. Light excites molecular

vibrations (heat)

UV PRODUCES COOLER EXCITATION IN POLYMERS

Laser Beam

Absorption region

Bulkpolymer



12/13


4445 Nicole Drive

Lanham, MD 20706

ISO 9001:2008

ISO 13485

Light absorption in

crystals & glasses

UV1. Photons excite

bound electrons2. Electron excitation

converted to lattice

vibrations (heat)

IR1. Photons excite

lattice vibrations

(heat)

Laser Beam

Absorption region

Bulkcrystal



13/13


4445 Nicole Drive

Lanham, MD 20706

ISO 9001:2008

ISO 13485

Machining layered

structures

Top layer shouldhave lower ablation

threshold energy

Examples: Polyimide on

copper

SiO2 onaluminum

ITO on glass


laser micro machining materials

Documents