Counter-flow Multi Inject for ALD Chamber Gas Distribution
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Solution Overview
Problem
Traditional atomic layer deposition processes face challenges in achieving uniform thickness profiles, particularly for high aspect ratio features, leading to non-uniform deposition and increased aspect ratios in submicron and smaller features in VLSI and ULSI technologies.
Innovation Solution
The implementation of a chamber lid assembly with a central channel and annular channels, featuring angled apertures to induce rotational gas flows in opposite directions, and a tapered bottom surface to enhance gas mixing and distribution, ensuring uniform gas flow and deposition across the substrate.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If traditional deposition processes are used, then the process is simple and well-established, but the deposition uniformity deteriorates for high aspect ratio features
Solution Approach 1:
The gas distribution system is segmented into multiple annular channels (first annular channel, second annular channel, third annular channel) with different aperture configurations. Each channel serves a specific region of the substrate, allowing independent optimization of gas flow patterns for different areas to achieve uniform deposition across the entire substrate including high aspect ratio features.
Solution Approach 2:
Different regions of the substrate receive gas flows with different characteristics. The first annular channel provides gas flow for the central region, the second annular channel for the intermediate region, and the third annular channel for the peripheral region. Each region's gas flow is optimized locally to account for variations in gas distribution and heat transfer, thereby achieving uniform deposition across the entire substrate.
2Manufacturing precision
If sequential gas pulses are used for ALD, then the deposition process is well-controlled, but the deposition profile becomes non-uniform with M-shaped thickness
Solution Approach 1:
The system dynamically adjusts gas flow patterns by sequentially activating different annular channels during the ALD process. The gas flow distribution changes over time to match the progression of the deposition cycle, with different channels being opened or closed at different stages to maintain optimal deposition uniformity throughout the process.
Solution Approach 2:
The ALD process employs periodic pulsing of reactant and purge gases through the multi-channel gas distribution system. Each deposition cycle includes periodic introduction of first reactant gas, purge gas, second reactant gas, and purge gas in sequence. This periodic action, combined with the multi-channel gas distribution, ensures uniform deposition by preventing gas phase reactions and maintaining consistent monolayer formation across the substrate.
3Productivity
If gas flow is increased to improve deposition rate, then productivity increases, but deposition uniformity deteriorates
Solution Approach 1:
The gas distribution system is divided into multiple annular channels that can be independently controlled. This segmentation allows the total gas flow to be distributed across different regions simultaneously, maintaining high overall deposition rate while ensuring each region receives appropriate gas flow for uniform deposition.
Solution Approach 2:
The multi-channel gas distribution system serves multiple functions: it distributes gas uniformly across the entire substrate area, controls gas flow patterns in different regions independently, and maintains deposition uniformity while supporting high deposition rates. This universal system replaces multiple separate gas delivery mechanisms with a single integrated solution.
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 results in improved deposition uniformity, reducing the risk of voids and seams in high aspect ratio features, enhancing the quality and reliability of submicron interconnects by maintaining a consistent deposition rate across the substrate.
Implementation Method 1
each aperture of the first plurality of apertures is angled with respect to the central axis so as to induce a rotational flow of a gas about the central axis in a first rotational direction; a second plurality of apertures disposed along a second horizontal plane through the housing to provide a multi-aperture inlet between the second annular channel and the central channel, wherein each aperture of the second plurality of apertures is angled with respect to the central axis so as to induce a rotational flow of a gas about the central axis in a second rotational direction opposite the first rotational direction
Implementation Method 2
a tapered bottom surface extending from the lower portion of the central channel to a peripheral portion of the chamber lid assembly
Data Source
AI summary
A chamber lid assembly includes: a central channel having an upper portion and a lower portion and extending along a central axis; a housing at least partially defining a first and a second annular channel, each fluidly coupled to the central channel; a first plurality of apertures disposed along a horizontal plane through the housing to provide a multi-aperture inlet between the first annular channel and the central channel; a second plurality of apertures disposed along a horizontal plane through the housing to provide a multi-aperture inlet between the second annular channel and the central channel, wherein the first and the second plurality of apertures are angled differently with respect to the central axis so as to induce opposing rotational flow of gases about the central axis; and a tapered bottom surface extending from the lower portion of the central channel to a peripheral portion of the chamber lid assembly.