Deposition of N-Heterocyclic Carbenes on Reactive Metal Substrates─Applications in Area-Selective Atomic Layer Deposition
Justin Lomax, Eden Goodwin, Mark D. Aloisio, Alex J. Veinot, Ishwar Singh, Wai-Tung Shiu, Maram Bakiro, Jordan Bentley, Joseph F. DeJesus, Peter G. Gordon, Lijia Liu, Seán T. Barry, Cathleen M. Crudden, Paul J. Ragogna
Abstract
Integrated circuits are presently constructed using top-down strategies composed of multiple etching and lithographic steps. As the feature sizes of these devices approach single-digit nm scales, existing fabrication methods introduce defects which require further corrective steps and are rapidly becoming ineffective for industry needs. To meet future scaling requirements, bottom-up fabrication methods which leverage differences in the local surface environment such as area-selective atomic layer deposition (AS-ALD) are promising but have been limited by the surface-binding energies of adsorbates. N-heterocyclic carbenes (NHCs) have shown excellent bonding to metal surfaces and are presented herein as next-generation carbon-based small molecule inhibitors (SMIs) for use in AS-ALD processes. NHCs demonstrate a preference for adsorbing onto metal surfaces over dielectric materials and enable the selective deposition of ZnO onto SiO 2 bands. NHC-based SMIs can be effectively removed by either thermal annealing at 350 °C or plasma treatment using hydrogen at 800 W for 60 s.