Vapor-deposited zeolitic imidazolate frameworks as gap-filling ultra-low-k dielectrics

• DOI: 10.1038/s41467-019-11703-x
• Publication Date: 2019-08-19T10:03:05Z
• Authors: Mikhail Krishtab; Ivo Stassen; Timothée Stassin; Alexander John Cruz; Oguzhan Orkut Okudur; Silvia Armini; Chris Wilson; Stefan De Gendt; Rob Ameloot
• Keywords: Science; Q; 02 engineering and technology; 0210 nano-technology; Article

AbstractThe performance of modern chips is strongly related to the multi-layer interconnect structure that interfaces the semiconductor layer with the outside world. The resulting demand to continuously reduce the k-value of the dielectric in these interconnects creates multiple integration challenges and encourages the search for novel materials. Here we report a strategy for the integration of metal-organic frameworks (MOFs) as gap-filling low-k dielectrics in advanced on-chip interconnects. The method relies on the selective conversion of purpose-grown or native metal-oxide films on the metal interconnect lines into MOFs by exposure to organic linker vapor. The proposed strategy is validated for thin films of the zeolitic imidazolate frameworks ZIF-8 and ZIF-67, formed in 2-methylimidazole vapor from ALD ZnO and native CoOx, respectively. Both materials show a Young’s modulus and dielectric constant comparable to state-of-the-art porous organosilica dielectrics. Moreover, the fast nucleation and volume expansion accompanying the oxide-to-MOF conversion enable uniform growth and gap-filling of narrow trenches, as demonstrated for 45 nm half-pitch fork-fork capacitors.