Low-k dielectric materials have become increasingly critical to the semiconductor industry as the interconnect delay becomes an overwhelming portion of the total device signal delay. Many attempts at lowering the dielectric constant involve using organic materials or introducing stochastic porosity; these solutions often lack the mechanical resilience that is necessary for devices to survive in-use operation and introduce challenges for integration within traditional semiconductor processing.

We demonstrate the fabrication of a 3-dimensional nano-architected low-k dielectric material that is comprised of hollow alumina tubes and contains 99% air. It has a stiffness of 30MPa and a dielectric constant well within the ultra low-k regime (below 2.0). We utilized two-photon lithography direct laser writing followed by atomic layer deposition to create these architectures. In addition to the low dielectric constant and high mechanical stiffness, these structural meta-materials exhibit exceptional energy absorption when uniaxially compressed and favorable electrical breakdown properties.