| The miniaturization of microelectronic devices and the need for higher computing speeds has created a demand for low dielectric constant materials. In this study, two functionalized polynorbornene copolymers are being investigated for this purpose: butyl norbornene/triethoxysilane norbornene and decyl norbornene/epoxide norbornene. Although polynorbornenes inherently possess properties that are attractive for microelectronics packaging, films of these polymers are not solvent resistant. The work presented in this study incorporates reactive additives into the polymer matrix to promote crosslinking reactions. The results of this study have shown that solvent resistant films are attainable in for both systems studied.; Two distinct reactions have been identified to occur during the cure of butyl norbornene/triethoxysilane norbornene systems with azide additives: azide crosslinking and silane crosslinking. Although both of these mechanisms result in the formation of a crosslinked polymer film, silane crosslinking was found to undesirably alter the dielectric and mechanical properties of the film. The results of a cure study indicate that cure atmosphere and temperature are critical parameters to determine which of these two reactions will control the final properties of the cured film.; Two reactions were also identified during the cure reaction of decyl norbornene/epoxide norbornene with cationic initiators: epoxide crosslinking and epoxide decomposition. Epoxide decomposition occurs at temperatures greater than 160°C and results in the complete loss of crosslinkable epoxide groups. Although both of these reactions have independent mechanisms, both reactions directly affect the level of crosslinking. As such, the final mechanical properties of decyl norbornene/epoxide norbornene films were determined to be strongly dependant on the extent of both epoxide crosslinking and decomposition reactions.; Finally, solvent swelling effects during the fabrication of a multilayer structure (polymer over metal lines on a cured polymer base) are investigated for both polynorbornene systems. Films that possess lower levels of crosslinking exhibited significant surface topography distortions. It is proposed that these distortions are the result of extraction of solvent during processing of subsequent layers over metal lines into a crosslinked underlying layer. |
