Two-Axis Motion Control for Uniform Films in Atmospheric-Pressure ALD
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Solution Overview
Problem
Existing atmospheric-pressure spatial atomic layer deposition (AP-SALD) systems face challenges in achieving uniform film thickness and shape due to variations in depositor head designs, which are undesirable for large-scale manufacturing applications.
Innovation Solution
A customized motion AP-SALD system is developed, featuring mechatronic control of key process parameters, including the axis of motion during film deposition. This system uses orthogonal linear stages to create a customized path of relative motion between the substrate and the depositor head, allowing for adjustments to account for inconsistencies in the depositor head.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional AP-SALD systems use fixed depositor head designs, then the deposition process is simple, but the film thickness uniformity deteriorates
Solution Approach 1:
The patent implements dynamic motion control in two orthogonal directions (x-axis and y-axis) for the substrate relative to the depositor head. This dynamic positioning allows the system to compensate for non-uniform deposition by adjusting the substrate position during the deposition process, transforming a static fixed-position system into a dynamic adjustable system that achieves uniform film thickness despite variations in depositor head design
Solution Approach 2:
The patent changes the spatial parameters of the deposition process by introducing two-axis motion control. By varying the substrate position coordinates (x, y) during deposition, the system can redistribute the deposited material to achieve uniform thickness. This parameter change approach transforms the deposition process from a fixed geometric constraint to a controllable spatial distribution process
2Manufacturing precision
If AP-SALD systems use variations in depositor head designs, then the system can be simplified, but the film shape uniformity deteriorates
Solution Approach 1:
The patent uses dynamic two-axis motion control to compensate for film shape non-uniformity. By adjusting the substrate position in both x and y directions during deposition, the system can correct shape variations caused by different depositor head designs, maintaining consistent film geometry without requiring perfectly uniform depositor head construction
Solution Approach 2:
The patent implements a feedback control mechanism where the deposition process monitors and adjusts the substrate position based on the desired film shape. The two-axis motion system responds to shape uniformity requirements by modifying the substrate trajectory, creating a closed-loop control system that ensures consistent film geometry regardless of depositor head variations
3Productivity
If conventional ALD processes use temporal control with purging, then the process is simple, but the deposition rate deteriorates
Solution Approach 1:
The patent employs periodic action through the two-axis motion pattern where the substrate moves in a rectilinear path, alternating exposure to precursor beams in a periodic cycle. This periodic motion enables continuous deposition without time-consuming purging steps, as the substrate systematically passes through different deposition zones in a repeating cycle, achieving high deposition rates while maintaining process control
Solution Approach 2:
The patent achieves continuous useful action by eliminating the purging step through two-axis spatial control. The substrate continuously moves through the deposition field in a programmed trajectory, receiving alternating precursor exposures without interruption for purging. This continuous motion-based deposition maintains high productivity while the control system manages the alternating precursor delivery
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 system achieves more uniform film thicknesses and shapes by adjusting the substrate path of motion, reducing non-uniformity from 8% to 2% in TiO2 films, and enabling higher throughput in a shorter amount of time.
Implementation Method 1
Each of the ALD precursor gases includes reactive ligands that participate in a self-limiting surface reaction to chemically deposit an atomic monolayer of the reacted precursor gases
Implementation Method 2
SALD can be performed at atmospheric pressure since the reactive ALD precursor gases are confined spatially by the inert gas zones
Data Source
AI summary
An atomic layer deposition system comprises: a depositor head having an active surface configured to discharge a first precursor gas, a second precursor gas, and an inert gas that separates the first precursor gas and the second precursor gas; a substrate spaced apart from the active surface of the depositor head; an XY motion device operably coupled to the substrate or the depositor head; and a controller configured to execute a program stored in the controller to move the XY motion device such that the substrate or the depositor head moves in a path, wherein a position of the substrate relative to the depositor head varies in both an X direction and a Y direction when the substrate or the depositor head follows the path. Also disclosed are a method for atomic layer deposition, and a method for reducing non-uniformity of a film produced by atomic layer deposition.