A study of polymeric materials for microelectronic applications: Low-k dielectric thin films and flip chip underfill encapsulants

The glass transition temperature (Tg) is a crucial parameter to predict the thermal stability of polymer thin films. Since there is no accepted model and comprehensive theory, so far, able to adequately describe and explain the thickness dependence of T g of polymer films, a model is developed for the thickness dependence of Tg of polymer films by considering both surface and substrate effects. It is predicted that the T g can either be reduced or enhanced with respect to its bulk value of exhibit a minimum as a function of film thickness, depending on the effect of polymer-substrate and polymer-surface interactions. A link between the proposed models and available but limited experimental evidence has been established.; Non-fluorinated FLARETM 2.0 has been considered as one of the promising low dielectric constant (low-k) interlayer dielectrics (ILDs) for interconnect applications. The first study of the thickness-dependent Tg of non-fluorinated FLARETM 2.0 films by using the ellipsometer is conducted in this work. The results of the ellipsometry experiments show that FLARETM 2.0 films exhibit a minimum of Tg as a function of film thickness. This behavior can also be well described by the proposed model and a good agreement is obtained.; Experimental investigation of the compatibility between the low-k ILD polymer films and the electroless copper (Cu) deposition process has been carried out. Various promising low-k ILD polymer films, including FLARE TM 1.0, FLARETM 1.51, FPI-45K FPI-136M, and PAE-2, have been chosen and their possible chemical and physical changes induced by the electroless Cu deposition solution treatments at different solution temperatures and treatment times have been studied. The solution-induced changes have been found in some low-k ILDs polymer films, indicating the importance of compatibility issue prior to the implementation of the interconnect node using Cu-based metallization in conjunction with the low-k ILDs.; The cure kinetics for advanced flip chip underfill encapsulants, such as "Fast flow" and "No flow" underfill encapsulants are studied. A model, which combines the effects of nth order reaction and the autocatalyzed reaction kinetics, is developed and applied to describe the cure kinetics in the present work. The reaction orders and the rate constants are determined to describe the curing progress. It is shown that the autocatalytic effect dominates the cure reaction kinetics for the studied underfill materials. The recommended cure schedules from material vendors have also been verified in comparison with the complete cure schedules determined by using Differential Scanning Calorineter (DSC).