Transverse Flow ALD for Uniform Atmospheric Deposition
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Solution Overview
Problem
Conventional atomic layer deposition (ALD) processes face challenges in achieving short reaction times, high chemical utilization efficiency, and uniform thin-film deposition on large substrates or moving webs, particularly at atmospheric pressures, due to limitations in gas distribution and purge mechanisms.
Innovation Solution
The Multiple Transverse Flow ALD (MTF-ALD) process employs a continuous distribution manifold with elongated outlet channels for transverse gas flow, allowing for efficient diffusion of gaseous materials across the substrate surface without vacuum purging, enabling uniform deposition at atmospheric pressure and on larger substrates or webs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of substance
If conventional ALD processes use vacuum purging between precursor exposures, then chemical utilization efficiency is improved, but device complexity and process time increase
Solution Approach 1:
The patent extracts and eliminates the vacuum purging step from the conventional ALD process. Instead of using vacuum to remove excess precursor, the process relies on controlled transverse gas flow and precise timing to clear the reaction chamber, thereby simplifying the overall process while maintaining chemical efficiency
Solution Approach 2:
The patent implements continuous transverse gas flow throughout the deposition cycle, eliminating the need for separate vacuum purging stages. This continuous flow maintains chemical utilization efficiency by constantly removing excess precursor while simplifying the process structure
2Manufacturing precision
If conventional ALD uses pulsed gas delivery, then uniform thin-film deposition is achieved, but reaction time and productivity are reduced
Solution Approach 1:
The patent employs periodic switching between different gas flows (precursor delivery, transverse flow, and purge flow) to achieve uniform film deposition. The periodic nature of gas phase switching ensures consistent precursor distribution while maintaining high deposition rates through continuous transverse flow
Solution Approach 2:
The patent uses dynamic control of gas flow rates and switching timing to optimize both film uniformity and deposition rate. The transverse gas flow velocity and precursor exposure duration are dynamically adjusted to maintain precision while increasing productivity
3Device complexity
If atmospheric pressure ALD is used, then equipment complexity is reduced, but gas residence time increases leading to poor chemical utilization
Solution Approach 1:
The patent uses controlled gas flow dynamics (pneumatics) to manage precursor removal at atmospheric pressure. The transverse gas flow creates effective precursor clearance without requiring vacuum systems, reducing equipment complexity while controlling gas residence time through flow rate optimization
Solution Approach 2:
The patent changes the gas flow parameters (velocity, direction, and timing) to compensate for the increased gas residence time inherent in atmospheric pressure operation. By optimizing these parameters, the process achieves efficient precursor utilization without vacuum equipment
4Area of stationary object
If transverse gas flow is used instead of vertical flow, then deposition on large substrates and webs is improved, but gas distribution complexity increases
Solution Approach 1:
The patent transitions from vertical gas flow (perpendicular to substrate) to transverse gas flow (parallel to substrate surface). This dimensional change in flow direction enables effective precursor distribution across large substrate areas and moving webs while using relatively simple manifold designs
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
MTF-ALD achieves high throughput and uniform thin-film deposition with improved chemical utilization efficiency, capable of operating at atmospheric pressure and low temperatures, suitable for large-area substrates and moving webs, while minimizing reaction time and gas residence time.
Implementation Method 1
the transverse flow is believed to supply and remove gaseous materials from the surface of the substrate substantially by a diffusion process through a thin diffusion layer
Implementation Method 2
The ALD process segments the conventional thin-film deposition process of conventional CVD into single atomic-layer deposition steps
Data Source
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AI summary
The present invention relates to a deposition process for thin film deposition onto a substrate comprising providing a plurality of gaseous materials comprising at least first, second, and third gaseous materials, wherein the first and second gaseous materials are reactive with each other such that when one of the first or second gaseous materials are on the surface of the substrate the other of the first or second gaseous materials will react to deposit a layer of material on the substrate and wherein the third gaseous material is inert with respect to reacting with the first or second gaseous materials. The process comprises flowing the gaseous materials along the length direction of a plurality of elongated channels across the surface of the substrate surface in close proximity thereto.