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Spatial atomic layer deposition (SALD) is a powerful thin-film deposition technique to control surfaces and interfaces at the nanoscale. To further develop SALD technology, there is need to deepen our understanding of the effects that process parameters have on the deposited film uniformity. In this study, a 3D computational model that incorporates laminar-flow fluid mechanics and transport of diluted species is developed to provide insight into the velocity streamlines and partial-pressure distributions within the process region of a close-proximity atmospheric-pressure spatial atomic layer deposition (AP-SALD) system. The outputs of this transport model are used as the inputs to a surface reaction model that simulates the self-limiting chemical reactions. These coupled models allow for prediction of the film thickness profiles as they evolve in time, based on a relative depositor/substrate motion path. Experimental validation and model parameterization are performed using a mechatronic AP-SALD system, which enable the direct comparison of the simulated and experimentally measured geometry of deposited TiO2 films. Characteristic features in the film geometry are identified, and the model is used to reveal their physical and chemical origins. The influence of custom motion paths on the film geometry is also experimentally and computationally investigated. In the future, this digital twin will allow for the capability to rapidly simulate and predict SALD behavior, enabling a quantitative evaluation of the manufacturing trade-offs between film quality, throughput, cost, and sustainability for close-proximity AP-SALD systems.
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Mechatronic Spatial Atomic Layer Deposition for Closed‐Loop and Customizable Process Control
Abstract A customized atmospheric‐pressure spatial atomic layer deposition (AP‐SALD) system is designed and implemented, which enables mechatronic control of key process parameters, including gap size and parallel alignment. A showerhead depositor delivers precursors to the substrate while linear actuators and capacitance probe sensors actively maintain gap size and parallel alignment through multiple‐axis tilt and closed‐loop feedback control. Digital control of geometric process variables with active monitoring is facilitated with a custom software control package and user interface. AP‐SALD of TiO2is performed to validate self‐limiting deposition with the system. A novel multi‐axis printing methodology is introduced usingx‐yposition control to define a customized motion path, which enables an improvement in the thickness uniformity by reducing variations from 8% to 2%. In the future, this mechatronic system will enable experimental tuning of parameters that can inform multi‐physics modeling to gain a deeper understanding of AP‐SALD process tolerances, enabling new pathways for non‐traditional SALD processing that can push the technology towards large‐scale manufacturing.
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- PAR ID:
- 10494667
- Publisher / Repository:
- Wiley Blackwell (John Wiley & Sons)
- Date Published:
- Journal Name:
- Advanced Materials Technologies
- Volume:
- 9
- Issue:
- 8
- ISSN:
- 2365-709X
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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