Dynamic Warpage Mitigation Strategies in High Density Laminate Package Assemblies
Balancing copper density, selecting ultra-low expansion glass cores, and profiling post-mold curing prevents dynamic warpage in high density laminate assemblies.
Shadow Moire Measurement
Meaning
Non-contact optical inspection evaluates the surface flatness of electronic packages and printed circuit boards across a range of temperatures. Through shadow moire measurement, engineers generate fringe patterns by projecting light through a reference grating onto the sample surface. This method tracks dimensional changes during the thermal cycle of a reflow process.
Optical Technique
Digital cameras capture the geometric patterns produced by surface deformation. The shadow moire measurement translates these patterns into a high-resolution 3D map of the surface height. This inspection is performed in a controlled heating chamber to simulate reflow, tracking how the package warps at various thermal stages.
Analysis of these images yields a precise measurement of the coplanarity limits at the melting point of solder.
Warpage Evaluation
Dynamic bending of substrates causes assembly failures like non-wet open solder joints. Using shadow moire measurement allows the identification of materials that do not maintain flatness at high temperatures. This analysis identifies defective component designs before volume manufacturing begins.
Yield Protection
Qualification of package materials ensures that thermal deformation stays within the coplanarity limits of the assembly process. Applying shadow moire measurement during the prototype phase prevents expensive design revisions later. This testing secures high assembly yields during mass production.