Electrical modeling of copper/carbon nanotubes for 3D integration

A model of copper and carbon nanotube (CNT) composite filled in through silicon vias (TSV) is developed to determine the electrical behavior of an emerging 3D interconnect technology. The copper/CNT composite is configured in a TSV structure to enhance electrical and mechanical interconnect properties. The TSVs are fabricated in a deep reactive ion etching process that produces tapered sidewalls which favors the metal filling process. Conductive TSVs are considered as a vertical pathway to integrate multiple chips in a stack, and to reduce interconnect length and wire delay. A realistic TSVs in the form of tapered sidewalls with different top and bottom diameters in the vias are used to study electrical behavior of Cu/CNT interconnects. Current density was investigated for different copper filling ratios, CNT diameters and via profile. Single walled CNTs were modeled to determine electrical behavior of the composite structures. The electrical modeling of Cu/CNT bundles filled in tapered vias will be used as design inputs in the fabrication of 3D interconnects. 3D electrically filled TSVs are considered as modern day electronic wiring scheme to connect devices in different layers. The paper discusses electrical modeling of Cu/CNT composites in tapered vias for high frequency applications.