In addition to the classical methods of experimental design in ultrasonic wire bonding such as Design of Experiment (DoE), the performance of shear and pull tests and the optical evaluation of the bond connection by microscope images, numerous supplementary experiments and measurements to investigate the influence of the bonding process parameters on the connection quality are carried out as part of the research work at the chair:
- Experimental vibration and modal analysis using laser vibrometry,
- Low frequency bond tests (<1 kHz) to measure dynamic process forces and high-speed recordings of the bond process for motion tracking analysis,
- Analysis of the ultrasonic softening effect for the parameterization of simulation models
Experimental vibration and model analysis is an important tool to investigate the influence of substrate vibrations during bonding on the bond quality. In order to avoid damage such as delamination of the substrate or damage to already set joints and to introduce the ultrasonic power into the joining zone as effectively as possible, the vibration excitation of the substrate should be as low as possible. Bonding tests on a copper rod allowed the influence of subsurface resonances on the vibration behavior during bonding to be investigated. It turned out that "over-resonant" bonding is advantageous to reduce background vibrations.