Atomic Regulation of Metal–Organic Framework Thin Film for Low-k Dielectric

Abstract

With the development of integrated circuit miniaturization, the RC delay caused by the interconnect resistance of metal wires and the capacitance of interlayer dielectric materials limits the high integration and miniaturization of electronic devices. As a promising low-k dielectric material, metal–organic frameworks (MOFs) can effectively alleviate this problem. In this work, we report an atomic regulation strategy of ultralow k MIL-53 film, achieved by converting an Al₂O₃ seed layer deposited via atomic layer deposition (ALD) and subsequently modifying through atomic layer infiltration (ALI). Thanks to the linear relationship between the thickness of the MIL-53 film and the Al₂O₃ seed layer prepared by ALD, precise nanoscale control of the MIL-53 films was realized. To meet both mechanical and dielectric property requirements, ALI modification is introduced, effectively regulating Young’s modulus and hardness of MIL-53 films from 19.5 and 0.17 GPa to 29.1 and 0.36 GPa, respectively, while the dielectric constant can be tuned from 1.93 to 2.59. The reconciliation of these properties is achieved by regulating the porosity of the MIL-53 framework through the additional Al–O clusters during the ALI. Furthermore, the superhydrophobic properties (140.7°) and the nearly constant dielectric constant after 9 months of aging reflect its potential as a dielectric insulating material. The proposed preparation and modification strategy of MOF films based on atomic regulation has broad potential for application in low-k interconnect integrated circuits.