Gap Protective Layer Deposition to Prevent Conductive Layer Oxidation
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Solution Overview
Problem
In semiconductor fabrication, the formation of a protective layer at the bottom of high-aspect-ratio gaps is inadequate, leading to oxidation of conductive layers and deterioration of electrical properties due to interaction with oxygen radicals during the deposition of silicon oxide insulating layers.
Innovation Solution
A method involving dual frequency RF power is used to decompose and densify a silicon-containing source layer, forming a protective layer that prevents oxidation by applying low frequency RF power to enhance ion-bombardment and decomposition at the gap bottom, and using nitrogen and hydrogen gases to improve step coverage and density, while inhibiting film growth at the top.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a protective layer is formed by conventional PEALD method, then the conductive layer is protected from oxidation, but the protective layer is not formed smoothly at the bottom of high-aspect-ratio gaps
Solution Approach 1:
The patent applies different gas compositions and process conditions to different regions of the gap structure. By introducing a carrier gas with specific properties and controlling the flow dynamics, the process achieves enhanced protective layer formation at the gap bottom while maintaining appropriate thickness at the top, thus addressing the non-uniform step coverage issue
Solution Approach 2:
The patent modifies process parameters including gas flow rates, pressure conditions, and temperature profiles during the PEALD process. These parameter changes enable better control over the deposition kinetics, allowing the protective layer to form more uniformly at the bottom of high-aspect-ratio gaps where conventional methods fail
2Productivity
If the aspect ratio of the gap structure increases, then the integration density increases, but the protective layer formation at the bottom of the gap deteriorates
Solution Approach 1:
The patent introduces dynamic control of gas flow and process conditions during the deposition process. By adjusting flow rates and pressure dynamically, the process adapts to the high-aspect-ratio geometry, ensuring adequate protective layer formation at the gap bottom even as integration density increases
Solution Approach 2:
The patent addresses the three-dimensional nature of high-aspect-ratio gaps by controlling gas distribution in multiple dimensions. The carrier gas flow pattern is optimized to ensure proper gas-phase transport and surface reaction conditions throughout the entire gap volume, from top to bottom
3Manufacturing precision
If activated oxygen-containing gas is supplied for silicon oxide deposition, then the insulating layer is formed, but the conductive layer is oxidized and electrical properties deteriorate
Solution Approach 1:
The patent forms the protective layer in advance before the silicon oxide deposition process. This preliminary protective barrier is established to prevent oxygen radicals from reaching and oxidizing the conductive layer during subsequent processing steps
Solution Approach 2:
The protective layer acts as an intermediary barrier between the activated oxygen-containing gas and the conductive layer. It allows the oxygen to pass through for insulating layer formation while preventing direct contact and oxidation of the conductive material
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
The method effectively forms a protective layer with improved step coverage and density, preventing conductive layer oxidation and enhancing the electrical properties of semiconductor devices by uniformly blocking oxygen radicals across the gap.
Implementation Method 1
The silicon-containing source gas adsorbed on the substrate may be bombarded by Ar radicals activated by RF power and physically decomposed into a film comprising fragments of silicon, nitrogen, carbon, hydrogen, and ligands
Implementation Method 2
Ar radicals activated by RF power
Implementation Method 3
a protective layer is introduced on the conductive layer, e.g. metal layer, prior to forming the silicon oxide layer
Implementation Method 4
applying low frequency RF power to enhance ion-bombardment and decomposition at the gap bottom
Data Source
AI summary
Provided is a substrate processing method for preventing a conductive layer from being oxidized due to activated oxygen gas when filling a gap contacting a conductive layer with oxide film. In an embodiment, a high frequency RF power and a low frequency RF power may be applied to form a dense protective layer in the lower portion of the gap and prevent the activated oxygen gas from reacting with and oxidizing the conductive layer when forming an insulating layer on the protective layer. In another embodiment, a film conversion gas and an inhibiting gas may be supplied to improve a step coverage of the protective layer and a uniform blocking to the activated oxygen gas into the conductive layer along the surface of the gap.