Non Local Strain Gradient Cohesive Zone Formulation for Microvia Corner Step Debonding
Non-local strain gradient cohesive zone modeling eliminates mesh-dependent stress singularities at microvia corner steps to accurately predict reflow debonding.
Micro Cantilever Testing
Meaning
Mechanical characterization techniques evaluate the strength and deformation of materials at the sub-micrometer scale using focused ion beam milling. Performing micro cantilever testing allows researchers to isolate specific microstructural features like grain boundaries or phases to measure their individual properties. This method avoids the averaging effect common in bulk material testing by focusing on a single small volume.
Beam Fabrication
Precision in the orientation of the beam relative to the crystalline structure of the material is carefully controlled during the fabrication phase. Performing micro cantilever testing allows for the study of how specific crystallographic planes respond to applied loads. Focused ion beam systems carve tiny beams from the surface of a sample with dimensions typically ranging from one to ten micrometers.
Load Application
Nanoindentation tools or specialized micro-actuators apply a force to the free end of the beam until it bends or fractures. The data collected during micro cantilever testing includes the load-displacement curve, which reveals the elastic modulus and the yield strength of the material. Sophisticated sensors track the movement of the beam with nanometer precision to ensure accurate calculation of stress and strain.
Scale Effect
Results from these experiments often differ from those obtained through traditional macroscopic testing due to the limited number of defects in small volumes. Observations in micro cantilever testing frequently show that smaller beams are stronger than larger ones, a phenomenon known as the size effect. Engineers use these findings to design more reliable micro-electromechanical systems and to predict the behavior of coatings in high-stress environments.