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Well defined graft copolymers have been synthesized by a nitroxide-mediated "living" free radical process using pre-formed macromonomers. Analysis of the graft systems revealed that the macromonomer was efficiently incorporated into the polymeric backbone to give block copolymers of controlled molecular weight and narrow polydispersities. An added benefit of the "living" free radical process is that macromonomers, such as polylactide or polycaprolactone, which contain reactive functional groups can be used to form novel graft systems using this approach. Functionalized monomers or polymeric initiators were also used in the copolymerization mixture to give graft systems with a variety of functional groups attached to the backbone.

The properties of a new aqueous-base-develop, negative-tone photosensitive polynorbornene have been characterized. High-aspect-ratio features of 7:1 (height:width) were produced in 70-lm-thick films in a single coat with straight side-wall profiles and high fidelity. The polymer films studied had contrast of 12.2 and low absorption coefficient. To evaluate the polymerÕs suitability to microelectronics applications, epoxy crosslinking reactions were studied as a function of processing condition through Fourier-transform infrared spectroscopy, nanoindentation, and dielectric measurements. The fully crosslinked films had an elastic modulus of 2.9 GPa and hardness of 0.18 GPa.

ABSTRACT:The miniaturization of microelectronic devices has created a demand for new low-dielectric-constant materials to be used as insulating layers between metal interconnects. In this study, a functionalized polynorbornene consisting of a copolymer of decyl norbornene and epoxide norbornene has been investigated as a low-temperature curing dielectric. Polynorbornenes possess properties that are attractive for microelectronics packaging; however, films of these polymers must be crosslinked in order to obtain the solvent resistance and low solvent swelling necessary for multilayer applications. Crosslinking of these materials was achieved by acid-catalyzed cationic crosslinking of epoxide side groups. The reactions that occurred during higher temperature curing of epoxy functionalized norbornene films were studied using Fourier transform infrared (FTIR) spectroscopy and thermogravimetric analysis. Epoxide crosslinking and epoxide decomposition reactions were identified and studied as a function of temperature and time.