Optimization of the CD Uniformity (CDU) in Silicon Oxide Spacer Process for 5 NM FIN SAQP Process Flow

As dimensions of semiconductor devices continue to shrink, ordinary film deposition processes, such as Chemical Vapor Deposition (CVD), Physical Vapor Deposition (PVD), cannot meet the requirement of the film uniformity and target thickness. Atomic Layer Deposition (ALD), based on surface-controlled and self-saturating adsorption reactions, where the film consists of sequential atomic layers, becomes more and more popular. To meet scaling requirements, multi-patterning solutions, like Self-Aligned Double Patterning (SADP), Self-Aligned Quadruple Patterning (SAQP) and Litho-Etch-litho-Etch (LE/LE), that utilize the already installed base of 193 nm immersion exposure tools are first adopted by the industry to not only reduce the linewidth, but also improve line edge roughness or line width roughness in 20/14 nm node and beyond, say 5 nm node. Within the framework of SAQP, the final Fin Critical Dimension Uniformity (CDU) and pitch walking is related to the profile and CDU of spacer deposition closely. In this study, we report a brief summary of ALD application in 5 nm FinFET process flow with a fin pitch of 24 nm. Meanwhile, we have demonstrated the oxide spacer deposition for 5 nm fin SAQP process, and the oxide spacer CD uniformity can be controlled to below 0.5 nm (3 sigma). Moreover, the deposition process is demonstrated on domestic made apparatus.