Meaning
Mechanical testing techniques evaluate local hardness and elastic properties by tracking load and displacement continuously during a contact cycle. Instrumented indentation measures both elastic deformation and plastic flow in a single test sequence without visual analysis of the residual imprint. This methodology answers whether thin coatings hold the required adhesion and hardness before high volume deposition begins.
Choosing a wrong indenter tip or ignoring thermal drift yields inaccurate elastic modulus values and leads to high scrap rates during production.
Displacement Sensor
Precision capacitors monitor the depth of penetration into the material with sub nanometer resolution. In instrumented indentation, the sensor captures the transition from elastic loading to plastic deformation as the tip advances. Software loops adjust the loading rate to keep strain rates constant across different sampling points.
Temperature changes in the test cabinet can expand the frame and distort the displacement data.
Hardness Evaluation
The maximum test force divided by the projected contact area determines the resistance of the material to deformation. Analyzing the unloading curve in instrumented indentation reveals the elastic recovery of the tested volume. Quality inspectors run arrays of these tests across coated wafers to map hardness uniformity before dicing.
When surface roughness is high, the changing contact area produces scattered hardness readings.
Yield Point
Onset of plastic flow during the loading cycle shows the mechanical threshold where the structure starts to fail. Continuous monitoring in instrumented indentation detects the pop in events that signal the initial dislocation movement in crystals. Engineers use these load curves to check the structural stability of microelectronic components under assembly forces.
