Hindrik de Vries | SALD B.V.: Can spatial ALD deposit high-performance moisture barriers at line speeds exceeding two meters per second?
00:11:58 - 00:14:33
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Summary of the clip:
Can spatial ALD deposit high-performance moisture barriers at line speeds exceeding two meters per second?
Evaluating the barrier quality of thin-film metal oxides on flexible polymers requires highly precise metrology. Using a DeltaPerm system, water vapor transmission rates (WVTR) are quantified by isolating a film sample under vacuum, injecting a controlled relative humidity on one side, and measuring the downstream pressure rise over time.
Experimental results show a sharp reduction in moisture permeability for aluminum oxide films as thickness scales from 10 to 20 nanometers, after which performance plateaus. This plateau is primarily governed by extrinsic pinhole defects introduced outside cleanroom conditions rather than intrinsic material degradation.
Crucially, this barrier performance is maintained at continuous web speeds of up to 2 meters per second. By tuning precursor concentration, the system achieves an extraordinary dynamic deposition rate of 30 nanometer-meters per second, validating the commercial readiness of spatial ALD for thin-film encapsulation.
In this short video, you can learn:
* The precise vacuum-based pressure-rise methodology used to measure water vapor transmission rates.
* The critical thickness threshold at which aluminum oxide films transition into high-performance barriers.
* How to maintain low permeability values at high line speeds by optimizing precursor concentration.
📋 **Clip Abstract** This clip demonstrates the high-speed deposition of aluminum oxide moisture barrier layers using spatial ALD at web speeds up to 2 meters per second. It explains the metrology used to measure water vapor transmission and discusses how precursor optimization yields a dynamic deposition rate of 30 nm·m/s.
#SpatialALD, #WVTRMetrology, #Al2O3Barrier, #RollToRollALD, #ThinFilmEncapsulation, #FlexibleElectronics
This is a highlight of the presentation:
A Paradigm Shift in Roll-to-Roll Spatial Atomic Layer Deposition for Perovskite Solar Cell Manufacture
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00:04:56 - 00:07:18
Why does Couette flow limit the ultimate speed of roll-to-roll spatial atomic layer deposition?
Why does Couette flow limit the ultimate speed of roll-to-roll spatial atomic layer deposition?
Spatial Atomic Layer Deposition (S-ALD) achieves deposition speeds up to 100 times faster than conventional temporal ALD by physically separating precursor zones rather than cycling gas pulses. While this allows continuous atmospheric processing, the absolute throughput limits of this geometry are governed by fluid dynamics rather than chemical kinetics.
At high linear velocities, a major bottleneck emerges in the form of drag flow and Couette flow. The moving substrate drags a boundary layer of gas with it, threatening to carry precursor molecules (such as trimethylaluminum) across the nitrogen isolation barriers and directly into the reactant zone.
To avoid parasitic gas-phase reactions and preserve self-limiting surface monolayer growth, the design of the deposition head must meticulously balance gas flow rates and nozzle spacing. Unidirectional web movement must be optimized to suppress this entrainment effect, ensuring that the spatial separation remains hermetic at high line speeds.
In this short video, you can learn:
* How spatial ALD utilizes gas nozzles and nitrogen barriers to eliminate temporal gas-purging steps.
* The fluidic challenges of Couette drag flow and precursor entrainment at high substrate velocities.
* Why 3D-printed gas nozzle geometry is critical for maintaining uniform precursor distribution.
📋 **Clip Abstract** This clip details the fundamental operating principles of spatial ALD and the fluid dynamic limitations encountered at high operating speeds. It explains how boundary layer drag flow can compromise spatial precursor separation, highlighting the engineering challenges of scaling atmospheric thin-film deposition.
#SpatialALD, #CouetteFlow, #PrecursorEntrainment, #RollToRollProcessing, #ThinFilmEncapsulation, #FlexibleElectronics
00:00:09 - 00:00:13
How does spatial atomic layer deposition (ALD) specifically address limitations in traditional ALD for solar cell manufacturing?
How does spatial atomic layer deposition (ALD) specifically address limitations in traditional ALD for solar cell manufacturing?
Salt is an original equipment manufacturer leading the industrialization of spatial atomic layer deposition in the solar industry. They possess over 15 years of experience in designing and building equipment for spatial ALD.
The company's primary objective is to develop dedicated R&D and high-volume sheet-to-sheet and roll-to-roll tools based on customer demand. These tools are designed for various applications, including the processing of aluminum oxide and tin oxide on large glass plates.
#SpatialALD, #SolarCellManufacturing, #ALDLimitations, #HighThroughput, #ThinFilmDeposition, #SemiconductorEquipment
00:07:20 - 00:09:58
Why is the textbook "floating drum" design for spatial ALD a dead end for commercial roll-to-roll production?
Why is the textbook "floating drum" design for spatial ALD a dead end for commercial roll-to-roll production?
The academic literature frequently showcases a spatial ALD design featuring a gas-bearing drum rotating counter-directionally to a floating web substrate. While theoretically elegant, this configuration presents severe mechanical and fluidic instabilities in a production environment due to the volatile balance required between web tension and gas-bearing pressures.
By forcing counter-directional movement, this legacy design actively exacerbates Couette drag flow, which severely compromises the maximum achievable web speed and film quality. Attempting to compensate by adding more slot pairs only increases mechanical complexity and cost while offering highly constrained throughput.
The modern paradigm relies on a fixed-drum web-supported system with a maximized wrap angle. This approach completely decouples the process chemistry from the mechanical web transport, enabling the integration of multiple fixed slot gas nozzles to scale film thickness without sacrificing mechanical stability or process control.
In this short video, you can learn:
* The core engineering flaws of the conventional floating-drum spatial ALD design.
* Why counter-directional drum rotation intensifies parasitic gas-phase reactions through Couette flow.
* How a fixed-drum, web-supported architecture with a maximized wrap angle simplifies mechanical scaling.
📋 **Clip Abstract** This clip critiques traditional counter-rotating, gas-bearing drum designs for roll-to-roll spatial ALD. It presents an alternative web-supported, fixed-drum architecture that decouples process gases from web transport to maximize speed and reliability.
#SpatialALD, #RollToRoll, #CouetteFlow, #WebTransport, #ThinFilmEncapsulation, #FlexibleElectronics