Testing, Qualification, Reliability

Reliability Assessment with FEM

© Fraunhofer IZM
© Fraunhofer IZM

Based on the geometry and material data, the mechanical and thermal behaviour can be simulated. Additionally, it is possible to take thermal-mechanical, electrical-thermal and electrical-mechanical couplings into account. By making use of failure models, the assessed stress limits or the lifetime can be determined and or predicted.

Important aspects are:

  • Determination of geometry: the geometry is determined on the basis of CAD-data or as part of the process and technology development.
  • Selecting material data: good materials data is a key element for reliability assessment. Material data is already available for several materials. For new materials or extended fields of application (e.g. high temperature), additional material properties can be characterised and prepared for the simulation.
  • Assessing production quality: stresses at the various stages of assembly can be investigated by simulation. Typical evaluation criteria are fracture stress and maximum permissible thermo-mechanical deformation.
  • Determining hot spot temperatures: simulating the temperature distribution and identifying hot spots for various operational states (power loss: static and transient), and cooling parameters as elements of thermal management.
  • Determining the lifetime: to evaluate long-term effects, mechanisms such as thermo-mechanical fatigue (e.g. at soldered joints, through vias), fracture processes, moisture diffusion, delamination, and electro-migration, are determined by using lifetime models– if necessary new lifetime models are developed.

More services relating to Testing, Qualification, Reliability

Mechanical and Thermal Characterisation of Materials

Determining mechanical and thermal parameters for materials for microsystem technology. Allowing for environmental conditions (e.g. humidity and temperature). Also determining parameters for the smallest samples and thin layers.

Thermal Management

Minimising the thermal resistance of packages by the design and optimisation of cooling concepts, taking into account high power losses, heat flux,and ambient temperatures.

Design assessment and optimisation for reliability

Using FEM analysis, alternative designs can be assessed and optimised in terms of reliability and durability.

Qualification and Test Center (QPZ)

New packages and solder alloys have to be tested in combination with different substrates with respect to their reliability behavior under defined thermal, climatic and/or mechanical stress conditions in the field.

Flyer Reliability Assessment by Numerical Simulation

Download (pdf/172KB)