Atomic Regulation\nof Metal–Organic Framework\nThin Film for Low‑<i>k</i> Dielectric

With the development of integrated circuit miniaturization,\nthe\nRC delay caused by the interconnect resistance of metal wires and\nthe capacitance of interlayer dielectric materials limits the high\nintegration and miniaturization of electronic devices. As a promising\nlow-<i>k</i> dielectric material, metal–organic frameworks\n(MOFs) can effectively alleviate this problem. In this work, we report\nan atomic regulation strategy of ultralow <i>k</i> MIL-53\nfilm, achieved by converting an Al<sub>2</sub>O<sub>3</sub> seed layer\ndeposited via atomic layer deposition (ALD) and subsequently modifying\nthrough atomic layer infiltration (ALI). Thanks to the linear relationship\nbetween the thickness of the MIL-53 film and the Al<sub>2</sub>O<sub>3</sub> seed layer prepared by ALD, precise nanoscale control of\nthe MIL-53 films was realized. To meet both mechanical and dielectric\nproperty requirements, ALI modification is introduced, effectively\nregulating Young’s modulus and hardness of MIL-53 films from\n19.5 and 0.17 GPa to 29.1 and 0.36 GPa, respectively, while the dielectric\nconstant can be tuned from 1.93 to 2.59. The reconciliation of these\nproperties is achieved by regulating the porosity of the MIL-53 framework\nthrough the additional Al–O clusters during the ALI. Furthermore,\nthe superhydrophobic properties (140.7°) and the nearly constant\ndielectric constant after 9 months of aging reflect its potential\nas a dielectric insulating material. The proposed preparation and\nmodification strategy of MOF films based on atomic regulation has\nbroad potential for application in low-<i>k</i> interconnect\nintegrated circuits.