ABSTRACT
As the components and structures involved in high-end electronic packaging are made smaller, the thermal gradient increases and the strain concentrations at electrical interconnections become more serious. When the deformations within those tiny regions are studied, the field of interest is small. Within such a small region, the relative displacements will be small even when the strains are large. Accordingly, extremely high spatial resolution and displacement sensitivity are needed to map the tiny displacements in a microscopic field effectively. A technique called microscopic moiré interferometry was used in this work, whereby the basic sensitivity of measurement was increased by a factor of two by means of an immersion interferometer. Then, fringe shifting and a robust algorithm (optical/digital fringe multiplication (O/DFM)) were used for a further increase by a factor of β [1,2]. This chapter illustrates several applications of microscopic moiré interferometry to thermal deformation analyses of various electronic packaging interconnections [3,4]. Normal strains and shear strains were determined effectively.
