Closely packed carbon nanotube (CNT) bundles are expected to have higher conductivity than copper and could potentially replace copper for electrical and thermal conductors in IC chips. However, it is extremely difficult, if not impossible, to controllably grow closely packed CNT bundles. We report on a novel postgrowth capillary densification method, which results in dramatic increase of CNT site density. Bare CNT pillars are densified approximately 15 times. High-density CNT micropillars and micrologs with round cross sections were fabricated from CNTs coated with parylene prior to densification. These CNT micropillars and micrologs could be used as basic building blocks for future IC interconnection. Electrical characterization results show that the densification process does not mitigate the electrical conducting performance of CNTs.