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In a paper presented at the Advanced Metalization Conference (AMC) at Colorado Springs, CO, SEMATECH and Rohm and Haas Electronic Materials researchers revealed work being carried out to provide a k-effective (keff) value of 2.5 in dual damascene work flows targeted by the ITRS roadmap for the 45nm node.

"The dual damascene integration that our team developed offers a potential solution for blocking precursor penetration and minimizing process-induced damage typically observed with ULK dielectrics containing interconnected pores," said Ward Engbrecht, lead author and a SEMATECH copper low-k integration project engineer.

The SEMATECH approach deposits the dielectric films by spin-on-deposition to form a matrix-porogen system that can be integrated as a dense material through chemical mechanical planarization, Rohm and Haas "Solid First" ILD process. The porogen then can be removed in a thermally-assisted ultraviolet cure process to create a system with a keff value of approximately 2.5. The Rohm and Haas spin-on low-k material is based on nanometer size pore forming polymers in the methylsilsesquioxane family, which the company patented in 2001.

"Our results show a process that has real promise as a solution for k-effective at 45 nm," said Sitaram Arkalgud, SEMATECH's interconnect director. "We will continue to refine our approach with an eye to reliability and eventual high-volume manufacturing."