Spatial Atomic Layer Deposition Repeating Motion Profile
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Solution Overview
Problem
Current spatial atomic layer deposition (SALD) systems face challenges in coating large substrates efficiently due to the need for complex equipment or long motion profiles, and there is a lack of modular systems that can handle different substrate form factors and provide uniform coatings without defects.
Innovation Solution
A deposition system with a deposition head that supplies gaseous materials in a sequence of zones, including inert and reactant zones, and a substrate positioner that moves according to a repeating motion profile to maintain gas separation and achieve uniform coating over longer substrates without exposing the deposition area to the external environment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a deposition head smaller than the substrate area is used, then the device complexity is reduced and manufacturing is simplified, but the coating uniformity and quality deteriorate due to inability to cover the entire substrate area
Solution Approach 1:
The substrate is moved dynamically through a repeating motion profile that includes forward motion into the deposition zone, backward motion to reposition, and pause phases. This dynamic motion allows a small deposition head to uniformly coat a large substrate by repeatedly exposing different regions to the deposition zone, solving the contradiction between small head size and large substrate coverage.
Solution Approach 2:
The substrate undergoes periodic reciprocating motion with forward and backward strokes, creating multiple exposure cycles. This periodic action enables the deposition head to deposit material uniformly across the entire substrate area over time, even though the head is smaller than the substrate, thereby maintaining coating uniformity while using a compact device.
2Productivity
If the substrate moves continuously in one direction, then the productivity increases, but the gas separation and deposition control worsen due to inability to maintain proper exposure timing
Solution Approach 1:
The substrate motion is made periodic with alternating forward and backward strokes, allowing the system to maintain precise deposition control through repeated exposure cycles. The periodic motion ensures that the substrate spends appropriate time in each gas zone (reactant, inert, purge) during each cycle, achieving uniform deposition while maintaining high productivity through continuous cycling.
Solution Approach 2:
The substrate is pre-positioned in the forward direction into the deposition zone before the backward motion begins. This preliminary positioning ensures that the substrate is optimally placed for deposition during the forward stroke, allowing continuous productivity while maintaining precise control over the deposition process through the structured motion sequence.
3Device complexity
If the substrate is exposed to external environment during deposition, then the device complexity is reduced by eliminating enclosed chambers, but the coating quality deteriorates due to contamination from external environment
Solution Approach 1:
Instead of enclosing the entire deposition area, inert gas zones are created locally at the deposition head output face. These localized inert zones provide contamination protection only where needed (at the substrate surface during deposition) while leaving the rest of the system open to the external environment. This solves the contradiction by providing contamination protection precisely where required without the complexity of a full enclosed chamber.
Solution Approach 2:
Inert gas acts as an intermediary between the external environment and the substrate surface during deposition. The inert gas zones create a protective barrier locally at the deposition interface, preventing contamination from the external environment while allowing the system to remain open. This intermediary approach enables open-system operation without compromising coating quality.
4Loss of time
If a single-pass linear motion is used, then the processing time is reduced, but the coating uniformity worsens due to inability to maintain gas separation throughout the substrate length
Solution Approach 1:
The substrate undergoes periodic reciprocating motion with multiple forward and backward cycles, creating repeated exposure opportunities to the deposition zone. This periodic action ensures uniform coating across the entire substrate length by allowing each region to receive adequate deposition exposure during different cycles, maintaining coating uniformity while completing the process efficiently through continuous cycling rather than requiring excessive single-pass time.
Solution Approach 2:
The repeating motion profile ensures continuous deposition action throughout the substrate length. By maintaining continuous motion with repeated cycles, the system ensures that every portion of the substrate receives deposition exposure during its pass through the deposition zone, achieving uniform coating across the entire substrate while minimizing total processing time through uninterrupted cyclic operation.
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
Enables high-quality coating of substrates longer than the deposition head size with a small apparatus, allowing for efficient coating of flexible and rigid substrates, including roll-to-roll webs, while maintaining gas separation and preventing contamination.
Implementation Method 1
Among the techniques widely used for thin-film deposition is chemical vapor deposition (CVD), which uses chemically reactive molecules that react to deposit a desired film on a substrate.
Implementation Method 2
a motion actuator configured to move the substrate in accordance with a specified repeating motion profile, wherein the repeating motion profile provides a net forward motion in the in-track direction and includes: a forward motion portion wherein the substrate moves a forward distance in the in-track direction
Data Source
AI summary
A material deposition system for depositing a material on a surface of a substrate includes a deposition head having an output face configured to simultaneously supply a plurality of gaseous materials in a sequence of gas zones. The gas zones include a deposition zone located between first and second inert zones. The deposition zone includes a first reactant zone adjacent to the first inert zone, a last reactant zone adjacent to the second inert zone, and one or more purge gas zones. A motion actuator moves a substrate over the output face with a repeating motion profile that prevents a region of active deposition on the substrate from being exposed to the external environment prior to having achieved a final material deposition amount. The repeating motion profile include a forward motion portion and a backward motion portion which is less than the forward distance by an ooch distance.