Characterization and Analytics

In order to calculate the service life of micro- and power-electronic components and assemblies using finite element simulation (FE), their material properties must be determined. This requires the analysis of material data and the determination of mechanical properties in small material volumes and at elevated temperatures, taking into account the manufacturing processes and the effects of material aging.

On the one hand, the development of preparation and fabrication methods for sample geometries on which classical tensile, compressive or bending tests can be performed enables the determination of material properties in electronic materials. The advantage here is the use of established measurement methods and evaluation routines. On the other hand, the process and aging behaviors of the materials are difficult to replicate in this way. A suitable alternative, however, is to take material samples directly from the actual component manufactured using the particular process, both before and after exposure to aging conditions such as stress tests (e.g., thermal shock or power-on cycle tests) or storage treatments (high temperatures, humidity, salt spray, UV radiation, or combinations thereof). This allows for the characterization of process- and age-dependent behavior. Since these material samples are very small, methods such as nanoindentation or micro-compression tests in the scanning electron microscope (SEM) need to be used, which enable the acquisition of precise material data even from miniscule volumes. When these measurement methods are combined with imaging techniques, strains can be determined simultaneously using digital image correlation (DIC).

Process-dependent material properties result from a material’s microstructure, with factors such as grain size, grain orientation and porosity playing a role. They can be analyzed by using techniques such as electron backscatter diffraction (EBSD) and focused ion beam (FIB) tomography. In addition, non-destructive measurement methods such as ultrasonic microscopy, laser acoustic analysis, and X-ray computed tomography (CT) provide valuable information on elastic properties, microstructure, and material-related changes before and after reliability testing.

Key topics:

• Acquisition of material data for finite element simulation (FE) and improvement of the experimental and data analysis methods
• Determination of process-dependent material properties: correlation of microstructure to process
• Analysis of material changes due to operational and environmental stresses and material aging
• Non-destructive analysis methods complementary to scanning electron microscopy (SEM) analysis
• Experimental validation of finite element simulation (FE)

Available measurement methods:

• Dynamic mechanical analysis (tensile, compressive and bending loads from -60 °C to 500 °C with up to 500 N in the frequency range from 0.001 to 200 Hz), combined with digital image correlation (DIC)
• Thermomechanical analysis (determination of the coefficient of thermal expansion (CTE), glass transition temperature, shrinkage)
• Nanoindentation (determination of temperature dependent local properties, including on thin films; modulus of elasticity, hardness, elastic-plastic material behavior, scratch tests)
• Scanning electron microscopy (electron backscatter diffraction (EBSD), energy-dispersive X-ray spectroscopy (EDX), focused ion beam (FIB), mechanical testing, heat stage)
• Shear and pull tests
• Scanning acoustic microscopy
• X-ray computed tomography (CT) with a load module for thermal or mechanical loading for applications with digital volume correlation (DVC)
• Measurement of wafer bow and thermally induced deformations on electronic assemblies by profilometry (-40 °C to 300 °C)
• Determination of residual stresses using Raman spectroscopy or fibDAC methods
• Material analysis in the cryogenic range from room temperature to 4 K for materials used in quantum packaging