Area-Selective Atomic Layer Deposition of Dielectric-on-Dielectric for Cu/Low-k Dielectric Patterns

摘要

Area-selective atomic layer deposition (AS-ALD) has received a great deal of attention in recent years because of itspotential to provide a more robust and controllable fabrication process for next generation electronic devices. In this paper,we study selective deposition of metal oxides on Cu/low-k dielectric patterns. We demonstrate that the inherent growthrate of ALD films is higher on Cu than on low-k surfaces, which indicates the importance of using organic molecules asan inhibitor to prevent ALD growth on Cu surfaces if the goal is to achieve area-selective deposition of materials on lowksurfaces. We show that vapor-phase dodecanethiol (DDT) can be used as an inhibitor. DDT is selectively deposited onCu surfaces and is effective at ZnO ALD blocking with selectivity greater than 90% after 100 ALD cycles (～17 nm). Withthe optimization of DDT deposition temperature and Al2O3 deposition conditions, the blocking ability of DDT against amore aggressive precursor is further improved and shows selectivity above 90% after 1.5 nm Al_2O_3 deposition.