Three-dimensional X-Ray laminography as a tool for detection and characterization of package on package(PoP) defects

The package-on-package (PoP) stacking assembly is a member of the SiP family. It is constructed by individual fabricated and tested packages from the same or different supplier provided in a stacked structure through solder joints. It can reduce the placement and routing areas on board and also allow one defective component to be replaced which is opposite to case of stacked Chip Scale Package (CSP). The fine and complex structures in miniaturized and highly 3D integrated devices are new challenges for non-destructive inspection. 3D X-Ray technique can capture three-dimensional information about the internal structure of an object. It is very useful for PoP defects analysis. As an introduction, the technology and methodology of 3D x-ray microlaminography are explained. The results from a microlaminography system adapted for failure analysis in a package on package (PoP) device are presented. It is shown that such results could not be obtained by two-dimensional (2D) x-ray or other nondestructive methods.