Electrical characterization of CNT contacts with Cu Damascene top contact

Carbon nanotubes (CNTs) were integrated successfully into 150 nm contact holes having a TiN underlayer and a Cu single damascene top contact module. All the integration steps for CNT integration, for patterning the Cu top contact and the mask-set used are compatible with 130 nm device technologies on 200 mm wafers. The first resistance yield plots for the CNT contacts on full wafer level are presented. For CNT grown at 540 °C in contact holes with aspect ratio 1.3, a single CNT contact hole resistance of 3.4 kΩ was achieved. The structure designed, the process flow presented here for CNT integration, and the automatic probing constitute a platform that allows benchmarking different recipes and process conditions. This constitutes a significant step forward towards the realization of a contact module with vertical CNT interconnects of superior quality. This is because the platform can speed up the learning cycle time for optimizing the CNT interconnect based on learning from the electrical performance.

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