Quantifying Microvia Target Pad Interfacial Shear Displacement under Thermal Shock
Microvia target pad interfacial shear displacement stems from CTE mismatch during thermal shock, demanding tight lamination control to prevent failure.
Laser Interferometry
Optical Metrology
Non-contact optical phase measurement quantifies surface topography variations and structural warpage across electronic components and circuit board substrates during dynamic heating profiles. Advanced inspection equipment applies laser interferometry to capture sub-micron out-of-plane displacements across ball grid array packages as temperature increases through reflow profiles. Coherent light beam interference fringe patterns generate high-resolution surface elevation maps in real time without physically touching the delicate substrate surface.
Thermal Warpage
Dynamic heating causes asymmetrical thermal expansion across multi-layer substrate structures, inducing component bowing and twisting that leads to solder bridging or open connections during SMT assembly. Interferometric measurements track substrate flatline deviations across preheat, reflow, and cooling stages to identify critical deformation thresholds. Utilizing laser interferometry enables process engineers to optimize temperature ramp rates and profile dwell times based on actual physical package distortion.
Real-time deformation mapping identifies coplanarity transitions that exceed maximum component land pattern placement tolerances.
Coplanarity Threshold
Surface elevation profiles generated by optical fringe analysis establish component acceptance limits prior to mass production runs. Packages exceeding fifty microns of out-of-plane distortion during simulated reflow are flagged for design modification or substrate material baking. Laser interferometry data provides the empirical foundation for thermal stress modeling and packaging layout qualification.