Flow Modulation Element for CVD Deposition Uniformity
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Solution Overview
Problem
In thin film deposition processes like CVD and PECVD, uniformity of film deposition across substrates is compromised due to spatial variations in momentum, thermal, and concentration boundary layers, particularly near the edges of substrates, leading to non-uniform mass transport and thermal transport.
Innovation Solution
The implementation of a flow modulation element that introduces an additive process gas beyond the peripheral edge of the substrate in a direction parallel to its surface, perturbing the boundary layer to enhance uniformity by injecting mass and momentum, thereby inflating the boundary layer and improving gas flow distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional gas distribution is used in CVD/PECVD processes, then the deposition process can proceed, but spatial variations in boundary layers cause non-uniform mass and thermal transport, leading to poor deposition uniformity across the substrate
Solution Approach 1:
The gas distribution system is segmented into multiple zones: a central gas distribution system for the main process gas and a peripheral flow modulation element for additive process gas. This segmentation allows independent control of gas flow in different regions of the substrate, enabling uniform boundary layer characteristics across the entire substrate surface while maintaining a relatively simple overall system architecture.
Solution Approach 2:
An additive process gas is introduced as an intermediary substance through the flow modulation element. This intermediary gas modifies the boundary layer characteristics by injecting mass and momentum, thereby improving mass and thermal transport without requiring fundamental changes to the main process gas distribution system.
2Manufacturing precision
If the boundary layer is left undisturbed near substrate edges, then the gas flow remains stable, but the boundary layer narrows and creates gradients that reduce deposition uniformity
Solution Approach 1:
The flow modulation element changes key parameters of the boundary layer by introducing additive process gas with different momentum and concentration characteristics. This modifies the boundary layer thickness and flow velocity profile, creating more uniform mass and thermal transport conditions across the substrate while maintaining overall flow stability through controlled gas introduction.
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 leads to more uniform film deposition across the substrate by mitigating the narrowing of boundary layers and gradients near the edges, resulting in improved deposition uniformity and process consistency.
Implementation Method 1
introducing an additive process gas beyond the peripheral edge of the substrate in a direction substantially away from the substrate and having a directional component substantially parallel to the upper surface of the substrate, thereby perturbing the boundary layer
Implementation Method 2
enhance uniformity by injecting mass and momentum, thereby inflating the boundary layer
Implementation Method 3
a continuous stream of film precursor vapor is introduced to a process chamber containing a substrate, wherein the composition of the film precursor has the principal atomic or molecular species found in the film to be formed on the substrate
Implementation Method 4
the precursor vapor is chemisorbed on the surface of the substrate while it thermally decomposes and reacts
Implementation Method 5
the precursor vapor is chemisorbed on the surface of the substrate while it thermally decomposes and reacts
Implementation Method 6
plasma excitation generally allows film-forming reactions to proceed at temperatures that are significantly lower than those typically required to produce a similar film by thermally excited CVD
Implementation Method 7
In a PECVD process, the CVD process further includes plasma that is utilized to alter or enhance the film deposition mechanism
Data Source
AI summary
A processing system for treating a substrate includes a process chamber, a substrate holder, a gas distribution system, and a flow modulation element. The process chamber has a pumping system to evacuate the process chamber. The substrate holder is coupled to the process chamber and supports the substrate. The gas distribution system is coupled to the process chamber. The gas distribution system introduces a process gas to a process space above an upper surface of the substrate. The flow modulation element is coupled to the substrate holder beyond a peripheral edge of the substrate. The flow modulation element includes one or more gas distribution openings that introduce an additive process gas beyond the peripheral edge of the substrate in a direction substantially away from the substrate. The additive process gas has a directional component substantially parallel to the upper surface of the substrate.