Quantitative Nano-Indentation Testing on the Universal Nano+Micro Materials Tester

 A novel quantitative nano/micro-tribometer has been introduced to characterize numerous physical and mechanical properties of liquid and solid thin films and coatings, with in-situ monitoring their changes during micro and nano indentation, scratching, reciprocating, rotating and other tribology tests. The instrument includes a nanoindenter integrated into the UNMT as shown in Figure 1.

Figure 1. UNMT with the nanoindenter and sample on the rotary drive

A classical nanoindentor configuration of voice coil actuator and capacitive sensing ensures a very low noise floor and large force and displacement range, making the instrument ideal for quantitative/qualitative studies on biomaterials, NEMS/MEMS, data storage and semiconductor industries. Proprietary contact surface approach, drift correction and machine compliance compensation routines ensure flawless performance of the instrument. Metrology of the newly introduced instrument is performed according to the ISO 14577 standard on instrumented nanoindentation.


Specifications:       

        Displacement Noise Floor: 1nm
        Force Noise Floor: 1µN
        Maximum Displacement: 300µm
        Maximum Force: 500mN

Figure 2 demonstrates performance of the newly developed instrument. A 5µm thick Cu layer was deposited on the 30nm thick Ta adhesive layer coated on the Si wafer. A cube corner diamond pyramid tool of 40nm radius was used for indents. The nanoindentation ramp loading profile consists of 10s loading, 3s holding and 10s unloading segments. Work hardening effect was induced by pin-on-disk tribology test. The curves show over 25% difference in contact stiffness, corresponding hardness and elastic modulus for untouched and work-hardened samples. Thus, a Cu layer work-hardening effect has been observed and quantified.

Figure 2. Nanoindentation loading/unloading cycles into Cu coated wafer

An intuitive software package is based on many years of experience in the field:

• A control software extracts elastic modulus and hardness from indentation loading-unloading curves by means of the Oliver-Pharr algorithm (which is also a basis for the ISO 14577)

• Force displacement curves can be plotted in linear, logarithmic or quadratic form in order to accommodate additional Hainsworth-Page, Chen's methods

• Time dependent behavior can be studied by load/displacement vs. time plots

• Elastic modulus/hardness vs. indentation depth plots are perfect for statistical studies

• An easy to create script allows programming of virtually any sophisticated test sequences (fragment is shown in Fig. 3).

Figure 3. Example of loading script