Defect Mitigation in Area‐Selective Atomic Layer Deposition of Ruthenium on Titanium Nitride/Dielectric Nanopatterns

Area‐selective deposition (ASD) receives increasing attention as a bottom‐up approach for nanoelectronic device fabrication. Uptake of ASD is however limited by defects, which manifest as undesired particle growth on the nongrowth surface. A defect mitigation solution is demonstrated for Ru ASD on TiN/SiO2 nanopatterns by making use of the size‐dependent Ru nanoparticle reactivity. During the initial stages of 1‐(ethylbenzyl)‐1,4‐(ethylcyclohexadienyl)ruthenium and oxygen (EBECHRu/O2) atomic layer deposition (ALD) on dielectrics, Ru particles are too small to catalytically dissociate oxygen, and their growth is suppressed. This phenomenon creates an ASD process window in which particles can be completely etched while retaining the integrity of the ASD pattern on a TiN growth surface. Decreasing the ALD temperature strongly suppresses defect growth, which can be used to expand the process window for ASD. The ASD process window is confirmed by self‐focusing secondary ion mass spectrometry (SF‐SIMS) with its low limit of detection while analyzing 104 structures simultaneously. No defects are detected for Ru ASD on 36 nm TiN/SiO2 patterns by SF‐SIMS. The Ru ASD process is applied for bottom‐up block patterning and functional hardmask patterns are obtained on 300 mm wafers. The approach followed in this work can produce defect‐free ASD processes for a wide variety of applications. Area‐selective deposition receives increasing attention as a bottom‐up approach for patterning, yet its uptake in industry is limited by defectivity. The EBECHRu/O2 growth mechanism can however be exploited to suppress defect growth on dielectrics. This allows the defects to be etched while retaining the Ru pattern obtained by selective deposition on a metallic growth surface.