Development of real time/variable sensitivity warpage measurement technique and its application to plastic ball grid array package

Far infrared Fizeau interferometry (FIFI) and shadow moire with enhanced sensitivity (SMES) are developed for real time warpage measurement of microelectronics devices. The methods are implemented in a compact apparatus that is based on a computer controlled environmental chamber. The apparatus combines the two methods to provide unique capabilities of thermally induced warpage measurement with variable sensitivity, ranging from 5.3-100 /spl mu/m. The methods are employed to document warpage of plastic ball grid array packages subjected to various thermal cycles.