Dynamic Substrate Motion for ALD Uniformity
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Solution Overview
Problem
Current atomic layer deposition (ALD) processes face challenges such as deposition non-uniformity due to stationary substrate positioning, incompatibility of ALD chemistries leading to unintended chemical vapor deposition (CVD) processes, and slow cyclic exposure processes resulting in low throughput.
Innovation Solution
The implementation of a processing chamber design that includes a rotatable support assembly with substrate heaters, allowing for dynamic movement of substrates between multiple spatially separated processing stations. This design enables angular offset positioning and continuous motion within process stations to enhance uniformity and throughput.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the substrate is positioned stationary in a processing station for primary deposition steps, then the deposition process can be performed with simple positioning control, but deposition non-uniformity occurs across the substrate surface
Solution Approach 1:
The substrate is moved dynamically within the processing station during deposition rather than remaining stationary. The support surface translates and rotates to expose different portions of the substrate to the gas injector at different times, creating uniform deposition across the entire substrate surface through motion-induced averaging of flux variations.
Solution Approach 2:
The substrate positioning is extended from a single fixed point to multi-dimensional motion including translation along the x and y axes and rotation about the central axis. This dimensional expansion allows the substrate to sample multiple positions and angles relative to the gas injector, achieving uniform deposition by averaging out local flux variations across the substrate surface.
2Productivity
If a time-domain ALD process is used with sequential gas flow and long purge/pump out times to prevent chemistry mixing, then chemical compatibility is maintained, but processing throughput is reduced
Solution Approach 1:
The processing chamber is divided into multiple spatially separated processing stations, each dedicated to specific process steps. This spatial segmentation allows simultaneous presence of incompatible chemistries in different stations without mixing, enabling faster processing cycles and higher throughput by eliminating the need for extensive purge times between chemistry transitions.
Solution Approach 2:
The system transitions from temporal separation of chemistries (time-domain ALD with sequential gas flow) to spatial separation (multiple processing stations arranged in a circular pattern). This dimensional shift allows incompatible chemistries to coexist in different spatial locations, dramatically reducing purge times and increasing processing throughput.
3Manufacturing precision
If the substrate is exposed to precursor gas in cyclic exposure cycles with monolayer saturation, then precise thickness control is achieved, but the deposition rate is slow
Solution Approach 1:
The substrate undergoes continuous motion during precursor exposure, translating and rotating to ensure all portions of the substrate receive equivalent precursor flux over time. This dynamic exposure maintains the precision of monolayer-by-monolayer deposition control while enabling higher overall deposition rates through continuous processing without interruption for repositioning.
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 solution effectively reduces deposition non-uniformity, maintains separation of incompatible gases, and increases processing throughput by allowing for independent environments and optimized plasma processing in each station.
Implementation Method 1
The support surfaces are rotatable around the central axis. A motor is connected to the support assembly and is configured to rotate the support assembly around the central axis.
Implementation Method 2
Each of the process stations comprises a gas injector having a front face
Implementation Method 3
a precursor is introduced into the chamber until all available active sites are occupied by chemisorption of the reactant
Implementation Method 4
optimized plasma processing in each station
Data Source
AI summary
Apparatus and methods to process one or more substrates are described. A plurality of process stations are arranged in a circular configuration around a rotational axis. A support assembly with a rotatable center base defining a rotational axis, at least two support arms extending from the center base and heaters on each of the support arms is positioned adjacent the processing stations so that the heaters can be moved amongst the various process stations to perform one or more process condition. The support assembly configured to offset the position of the substrate with respect to the processing stations.