Nanoindentation

Nanoindentation (NI)

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Nanoindentation (NI) is a nano-mechanical test that provides the mechanical properties from precise compliance measurements. In addition, nanoindentation analysis is especially useful in measuring properties such as the modulus and hardness of various shaped and sized materials. For example, nanoindentation is useful to characterize semiconductor thin films, packaging, advanced alloys, thermal barrier coatings, polymer viscoelasticity, scratch and wear resistance.

Nanoindentation uses contacts, where a probe is pushed into a solid, while the penetration depth is recorded simultaneously with near-atomic resolution. In addition, this capability can reduce the probing volume down to an order of magnitude of 100 nm³, which allows the use of continuum mechanical contact models to extract properties like hardness and modulus for thin films and constituents of microstructures. The contact geometries and testing methods are configurable so that mechanical characterization can be extended to brittle properties, adhesion, stress-strain, scratch, wear or structural stiffness of microstructures.

Theory of instrumented-indentation

Nanoindentation experiments are typically conducted either quasi-statically or dynamically, while the properties are extracted using contact or oscillator physics.

Examples of Nanoindentation

Firstly, a quick assessment of wafers or thin films on wafers during quality control
Investigation of effects during process development (e.g. PVD, CVD) in semiconductor device fabrication
Simulation of contact conditions observable in practical use-cases for failure analysis
Mapping spatial distribution of mechanical characteristics on multi-phase materials
Studying deformation mechanisms (elasticity, plasticity, brittle behavior or phase-transformation)
Accurate assessment of structural compliance of microstructures and particles
Gaining highly localized insights into stress-strain relationship of a material
Studying adhesion properties on surface and thin film interfaces
Obtaining accurate mechanical property values for input into physical modeling (e.g. finite element or analytical analysis)
Lastly, an assessment of viscous material properties through creep and relaxation testing, as well as dynamical mechanical analysis on the nanoscale

Ideal Uses of Nanoindentation

Firstly, quantitative mechanical characterization of highly-localized material properties, including hardness, elastic modulus, fracture toughness, creep, topography
Secondly, obtaining other material characteristics, including storage- and loss-modulus from dynamic mechanical analysis (DMA) on nano-scale, thin film adhesion, wear, friction and structural compliance

Advanced Loading Techniques

Firstly, quasi-static indentation:

Trapezoid
Multiple partial unloading
Stiction
Creep
Grid

Secondly, dynamic indentation:

Variable load
Variable frequency
Continuous stiffness
Modulus mapping

Thirdly, nano-scratch:

Constant load
Progressive load
Tilt corrected multi-pass

Finally, in-situ imaging:

Contact mode
(Scanning-) wear

Strengths

Accurate test positioning on features of few-100 nm size
Quantitative characterization of thin films
Wafers up to 6 in analyzed intact
Dry and liquid environment
Cross-section analysis (including in-house preparation)
Numerous non-indentation applications, which are solely custom-designed around precise control and measurement of force and displacement in mixed-load-conditions at small scales

Limitations

Firstly, bulk specimen size limitations 4x2x2 inches
Secondly, thin film measurements under 10 nm thickness should be considered semi-quantitative
Finally, potential problems with extremely rough surfaces