Selective Silicon Oxide Deposition via Plasma-Activated ALD
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional semiconductor fabrication techniques face challenges in selectively depositing silicon oxide on silicon oxide surfaces while avoiding deposition on silicon nitride surfaces, often resulting in non-selective deposition or void formation in small features due to the lack of differentiation in reactivity between the two surfaces.
Innovation Solution
A method involving thermal atomic layer deposition (ALD) is employed, where a substrate with exposed silicon oxide and silicon nitride surfaces is treated with aminosilane and an oxidizing agent, selectively forming silicon oxide on the silicon oxide surface by modulating the reactivity using plasma activation and specific gas flow rates, while preventing deposition on the silicon nitride surface by forming primary amine groups that are not susceptible to reacting with silicon-containing precursors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional deposition techniques are used, then deposition can be performed on both silicon oxide and silicon nitride surfaces, but selective deposition of silicon oxide on silicon oxide surfaces while avoiding silicon nitride surfaces cannot be achieved
Solution Approach 1:
The silicon nitride surface is pre-treated with ammonia plasma to form primary amine groups before the deposition process. This preliminary action modifies the surface chemistry to prevent subsequent reaction with silicon-containing precursors, enabling selective deposition on silicon oxide while avoiding silicon nitride surfaces
Solution Approach 2:
The invention changes the chemical state of the silicon nitride surface by converting it from a reactive state to a state with primary amine groups through plasma treatment. This parameter change in surface chemistry creates the necessary reactivity differentiation between silicon oxide and silicon nitride surfaces for selective deposition
2Manufacturing precision
If conventional techniques are used, then deposition can proceed uniformly, but void formation occurs in small features due to lack of selective deposition
Solution Approach 1:
The invention applies different surface properties to different regions: silicon oxide surfaces maintain their native reactivity for deposition, while silicon nitride surfaces are modified with primary amine groups to be non-reactive. This local differentiation in surface quality enables conformal deposition in small features without void formation
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach enables selective and conformal deposition of silicon oxide on silicon oxide surfaces relative to silicon nitride surfaces, improving the precision and reducing void formation in small features, thereby enhancing the fabrication process for semiconductor devices.
Implementation Method 1
exposing the substrate to a aminosilane to adsorb the aminosilane to the exposed silicon oxide surface
Implementation Method 2
exposing the untreated silicon nitride surface to ammonia and igniting a plasma for a duration between about 1 second and about 10 seconds to form the exposed silicon nitride surface including primary amine groups
Implementation Method 3
performing a thermal atomic layer deposition reaction including exposing the substrate to an oxidizing agent, whereby the thermal atomic layer deposition reaction selectively forms silicon oxide on the exposed silicon oxide surface
Data Source
AI summary
Methods and apparatuses for selectively depositing oxide on an oxide surface relative to a nitride surface are described herein. Methods involve pre-treating a substrate surface using ammonia and/or nitrogen plasma and selectively depositing oxide on an oxide surface using alternating pulses of an aminosilane silicon precursor and an oxidizing agent in a thermal atomic layer deposition reaction without depositing oxide on an exposed nitride surface.