Oval ALD Reaction Chamber for Uniform Precursor Flow
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Solution Overview
Problem
Existing atomic layer deposition (ALD) reaction chambers face inefficiencies due to non-uniform gas flow across round substrates, leading to prolonged cycle times and reduced material efficiency, primarily caused by the bypass effect where precursor gas molecules bypass the substrate surface, resulting in underdosing and prolonged purging times.
Innovation Solution
The design of an ALD reaction chamber with an oval or oval-like shape, featuring an increasing width along the longitudinal central axis towards the width central axis and a decreasing width towards the second end, allows side walls to be positioned close to the substrate, ensuring uniform gas flow and minimizing the bypass effect by providing sufficient space for precursor gas molecules to spread before reaching the substrate.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If straight reactor walls are used with gas inlet and outlet at opposite ends, then the reactor structure is simple, but gas flow becomes non-uniform causing bypass effect and poor precursor distribution
Solution Approach 1:
The reactor walls are designed with curved geometry instead of straight lines. The side walls include first and second curved portions that diverge from the central axis, creating an oval-shaped cross-section. This curvature redistributes gas flow paths, eliminating the bypass effect while maintaining structural simplicity.
2Productivity
If gas inlet and outlet are positioned close to substrate edges, then gas exchange is efficient at edges, but middle areas receive insufficient gas dosage
Solution Approach 1:
The reactor design creates asymmetric flow paths relative to the substrate position. The curved wall portions are positioned to redirect gas flow toward the substrate center, ensuring that the middle areas receive adequate precursor dosage while maintaining efficient edge exchange.
3Manufacturing precision
If high overdose of precursors is supplied to compensate for underdose in middle parts, then coating uniformity improves, but purging time increases and efficiency decreases
Solution Approach 1:
The curved wall geometry preconditions the gas flow before it reaches the substrate, ensuring uniform precursor distribution from the start. This eliminates the need for compensatory overdose and reduces purging time by preventing excess precursor accumulation.
4Ease of operation
If round substrates are processed in straight-walled reactor, then edge areas have good gas exchange, but middle areas experience gas flow stagnation
Solution Approach 1:
The curved wall portions create flowing gas paths that prevent stagnation in the substrate middle area. The divergent geometry directs gas flow across the entire substrate surface, reducing residence time while maintaining good edge exchange.
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 configuration enhances gas flow dynamics, reduces the need for overdose precursors, and shortens purging times, resulting in improved material efficiency and faster processing times while maintaining uniformity across the substrate surface.
Implementation Method 1
The gases are supplied from the gas inlet 30 and discharged from the gas outlet 40 such that the gases flow in the reaction chamber 20 from the gas inlet 30 to the gas outlet 40. The gas flow between the gas inlet 30 and the gas outlet 40 flows across the surfaces of the one or more round shaped substrates.
Data Source
AI summary
An atomic layer deposition reaction chamber and a reactor. The reaction chamber includes a first end, a second end, and a longitudinal central axis (X) between the first and second ends and a length (L) in the direction of the longitudinal central axis (X), and a first side wall and a second side wall defining width (W) of the reaction chamber, and a width central axis (Y) extending perpendicularly to the longitudinal central axis (X). The reaction chamber has along the longitudinal central axis (X) an increasing width (W) from the first end towards the width central axis (Y) and a decreasing width (W) from the width central axis (Y) towards the second end.