Area-Selective Atomic Layer Deposition on Metal/Dielectric Patterns: Amphiphobic Coating, Vaporizable Inhibitors, and Regenerative Processing

Abstract

Area-selective atomic layer deposition (AS-ALD) has drawn significant attention in the past decade because of the potential applications in bottom-up processing, which enables fabricating nanostructures at the atomic level without multiple patterning and lithographic processing that could easily cause alignment issues. Although AS-ALD has been demonstrated using various self-assembled monolayers (SAMs), it is still challenging to develop wet SAM deposition for AS-ALD that is suitable for industrial and semiconductor processes. In this work, we demonstrate highly effective AS-ALD of Al 2 O 3 on Co/SiO 2 patterned wafers using fluorinated thiol in both solution and vapor phase. Compared with conventional SAMs using alky-thiols, the fluorinatedthiol SAMs demonstrate greater blocking ability against ALD precursors owing to excellent hydrophobicity. Furthermore, much shorter deposition times can be achieved in vaporizable fluorinated thiol molecules, improving processing throughput and productivity. Most importantly, the SAM regeneration and redosing processes can further enhance the selectivity of AS-ALD, opening a promising avenue to realize the bottom-up approach in practical semiconductor applications.

Reactive Vapor-Phase Inhibitors for Area-Selective Depositions at Tunable Critical Dimensions

“…In another approach, the modification of a surface with an organic material can be used to deactivate it and inhibit film growth. − The latter strategy may offer the versatility of selectively coating a broad number of metal or dielectric surfaces commonly encountered in device builds. Organic inhibiting materials can be deposited either by solution or vapor-phase methods, generally dependent on the vapor pressure of the molecule. , Solution deposition methods often use self-assembled monolayers (SAMs) to form densely packed inhibiting layers, driven in large part by headgroup chemistry, which presents a strong enthalpic driving force to bind with a surface (such as thiols, phosphonic, and hydroxamic acids). Formation of the monolayer is further aided by interactions between aliphatic side chains through van der Waals forces to form crystalline monolayers (the magnitude of the interaction depends on the length of the side-chain) .…”