ABSTRACT
Applications of moiré interferometry are introduced for the determination of effective CTEs (coefficients of thermal expansion). In electronic packaging, materials and components with very different properties are assembled at elevated temperatures and tested by temperature cycles. CTE mismatch in a packaging system can cause significant thermal strains and consequent fatigue failures in the interconnections during the assembly processes and the temperature cycle tests. It can also cause poor dimensional stability and difficulties in assembly processes [1–3]. It is crucial, therefore, to determine the CTE values in the electronic package designs and reliability predictions accurately. In order to determine the CTE values of electronic components and their variation from region to region, thermal deformations of samples have to be measured with high sensitivity and resolution. As a whole-field technique, moiré interferometry is an ideal method. Global and local CTE values can be determined from the whole-field thermal deformations provided by the moiré interferometry technique.
