introduction to nano-scale mechanical properties testing micro materials ltd. wrexham, uk

MEASURING NANOTECHNOLOGY

MICROMATERIALS

Introduction to Nano-scale Mechanical Properties Testing

Micro Materials Ltd. Wrexham, UK.


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Outline

• Depth-sensing indentation• The NanoTest system• Case studies• Nanoindentation – bond pads• Nano-impact – fatigue of DLC films• Polymer nanoindentation

• Summary


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What is depth-sensing indentation?

loading unloading

• force, displacement and time are recorded throughout the indentation of a test sample by a diamond probe

• elastic and plastic propertiesof the sample determine theshape of the unloading curve

Scanning = transverse sample movement during loadingImpact = sample oscillation at constant load

coating

substrate


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Where does depth-sensing indentation fit in?

• Surface/near-surface

• Mechanical properties of thin films and coatings

• Hardness

• Modulus

• Creep

• Depth-profiling

• Wear resistance

• Interfacial adhesion

• Fracture toughness

• Surface

• Friction

• Adhesion (local)

• (Wear)

• Topography

• Role of specific chemical interactions?

• Bulk

• Hardness of thick coatings and bulk materials

• Fracture toughness of bulk materials

SPM Nanoindentation Macro-hardness


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Micro Materials Limited -growing market share in a fast growing market...

Source: British Library on-line database. Keyword search on “nanoindentation”.


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The most versatilenanomechanicalproperty testing centre...

The NanoTest system

2 loading heads:

Nano - 10 N - 500 mN

Micro - 0.1 N - 20 N

3 modules:

IndentationScanningImpact

10 options including:

High temp testingContinuous compliancePin-on-disk wearMicroscopes


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The NanoTest pendulumAdvantages of the pendulum over vertical loading instruments include…

• large samples possible• calibrated contact load• high temperature stage• sample oscillation• options such as pin-on- disk wear testing and 2D levelling stage

Original design - University of Lancaster, UK, Newey, Wilkins and Pollock, J Phys E, 1982, pp119-122.Micro Materials formed 1988 by Dr Jim Smith, first instruments sold 1992.


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nickel plating

Al pad

passivation layerSi wafer

Quantitative measurement of themechanical properties of thin films

Aim: determine the hardness and modulus of top layer in IC bond pad without substrate influence

Technique Applied ForceSPM nN-NNanoTest 10 N-500 mNMicroTest 100 mN - 20 NHardness N-kN

Comparison of load ranges

Indentation


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NanoTest indentation module

Techniques• Nanoindentation• Microindentation• Load-partial-unload• High temperature testing• Continuous compliance

Properties• Hardness• Elastic modulus• Fracture toughness• Adhesion• Creep• Elastic and plastic work• Elastic recovery parameter• Stress-strain

Indentation


MICROMATERIALS Indentation


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Depth-profiling of mechanical property variation

Load-partial-unloadtechnique

20-cycle load-partial-unloadDepth controlled 50-1000 nmExperiment time 30 minAnalysis time 30 sec

• rapid and quantifiedvariation in hardnessand modulus with depth

Indentation


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• “1/10 rule” - for a hard coating on softer substrate

Hardness of 5 m Ni-based top-layer of bond pad

constanthardness

decreasinghardness

coating coating + substrate coating

+ substrate

Indentation


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How homogeneous is mycoating?

An example of nanoindentation as a QA tool

• rapid, automatic schedulingof arrays of indentations

Indentation


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Precise indent placement witha 4-objective high resolution metallurgical microscope

NOTE: 1 objective can be replaced by contact/AC mode SPM

Mapping variations in hardness and elasticity at the nanoscale

• studies of nano- and micro- scale phase separation

Indentations along 10 m alloy interfacebetween stainless steel surfaces

Indentation


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• indentation + residual stress = coating failure

Nanoindentation-induced adhesion failure

Adhesion failure

DLC on Si

Indentation


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NanoTest scanning module

for…

• Scratch testing• Nano- and micro- friction• Adhesion• Profilometry• Acoustic Emission• Fatigue wear

“Nanotribometer”

Scanning


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Ramped load scratch testing (1)

Film failure at critical normal load Lc is revealed by...

• Depth change• Acoustic Emission• Friction Force• Topography Scan• Optical Microscopy

Adhesion failure at critical load of 3.2 mN

Scanning


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Ramped load scratch testing (2)

• qualitative ranking of test coatings and multilayers at the development stage

Scanning


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Multi-pass sub-critical load scratch testing

dplast

dtotalExperimental parameters:25 m Rockwell probescratch load:- ramped to 1 mNtopography load 0.1 mNscan speed 0.5 m/s Nano-scratching wear of polymer film

Repeat scratches over the same wear track reveal...• fatigue behaviour• cohesive failure (fracture)• adhesive failure (delamination)

Scanning

2, 4, 6

1, 3, 5, 7


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NanoTest impact module

for…

• Impact testing• Contact fatigue testing• Erosive wear testing• Fracture toughness• Adhesion testing• Dynamic hardness

The only commercial nano-impact tester available

Impact


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Impact testing - simulating fatigue wear and failure

• adhesion failure• fracture

Impact


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Impact Testing of a brittle TiN coating

• For bulk materials wear rates are determined from changes in probe depth

• For coatings, time-to-failure is related to the bonding strength to the substrate

100 mN applied load ison throughout test

80 Hz oscillation frequency

Oscillation on 30 s after startOscillation off 30 s before end

Film failure after 250 s

Impact


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To summarise….

1. Nanoindentation techniques are essential in the optimisation of the mechanical properties of thin films and coatings

2. The NanoTest has large range of testing techniques, and thereforeoffers a complete testing capability

3. These techniques are possible due to the unique pendulum design

4. The high temperature option and impact module allow testing undercontact conditions that can closely simulate those in service

5. The versatility and wide range of options have resulted in the systemfinding applications in….


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NanoTest systems are in regular use in…

MIT USAEastman Kodak USAPhilips NetherlandsHP SingaporeGintic SingaporeCambridge Uni UKBarcelona Uni SpainVITO BelgiumNPL UKEnterprise IrelandSalford Uni UKCranfield Uni UK

Timken USARPI NY USAAGFA DELOT Oriel DEPaisley UKLoughborough UKTU Clausthal DEUMIST UKDERA UKLeeds Uni UKICM Madrid SpainTrivandrum India

...and many more - over 75 sites worldwide


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• Automotive• Bearings• Biomedical Devices• Ceramics• Composites• Contact Lenses• Cutting Tools• Hard Coatings• Laminates• Magnetic Disks• Microelectronics• Optical Coatings

• Optical Disks• Packaging Materials• Paints• Paper Coatings• Pharmaceuticals• Photographic Film• Polymers• Powders• Printing Plates• Semiconductors• Thin Film Adhesion• Turbine Blades

Current NanoTest application areas include…

...future application areas will be in?

introduction to nano-scale mechanical properties testing micro materials ltd. wrexham, uk

Documents

test sample

transverse sample movement

diamond probe elastic

nanotest system2

hardnessand modulus

example of nanoindentation

minanalysis time

mnmicrotest100 mn