Molecular insights on interfacial properties and moisture uptake of plastic packaging materials

Product trends such as chip scale packaging and high density electronic interconnects are driving technologies towards increased complexity and reduced feature sizes. Two particularly important technical challenges involving plastic packages are to enhance the robustness of multi-component material interfaces and to improve the resistance of plastic assemblies to the effects of moisture. This presentation will review recent insights gained at NIST within its electronic packaging, interconnection and assembly program. First, a discussion of the properties and moisture susceptibility of buried polymer interfaces is presented. Using neutron and X-ray reflectivity techniques, NIST can directly measure the CTE and hygroscopic expansion of extremely thin polymer films. Neutron techniques can also yield information about the concentration profile of deuterated water near an interface. Second, results from moisture uptake and egress studies within a molding compound are also presented. Using solid state NMR, NIST can detect different forms of absorbed water and observe how this water responds to changes in the external environment