ALD Precursor Pulse Dynamics for Uniform Substrate Coverage
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Solution Overview
Problem
Atomic layer deposition (ALD) on complex substrates or multiple parallel substrates faces challenges of high precursor consumption and uneven substrate coverage due to the time required for precursor diffusion and the proximity of substrates, which increases costs and reduces efficiency.
Innovation Solution
A method and system for ALD that control the precursor flow rate and partial pressure, with higher average flow rate and partial pressure during the initial half of the pulse and lower during the second half, optimizing precursor usage and coverage uniformity by adjusting flow and pressure control valves within the process chamber.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a large amount of precursor per pulse is used to ensure complete and uniform coverage on complex substrates, then substrate coverage uniformity is improved, but precursor consumption increases
Solution Approach 1:
The patent applies dynamics by making the precursor flow rate time-dependent rather than constant. The flow rate is dynamically adjusted during the pulse duration, starting high to ensure complete coverage of complex substrates and then decreasing to reduce overall precursor consumption. This resolves the contradiction by optimizing coverage uniformity during the critical initial phase while minimizing waste in the later phase.
Solution Approach 2:
The patent changes the parameter of precursor flow rate from a static value to a time-varying function. By modifying the flow rate parameter over time (high initially, then low), the system achieves both complete coverage of complex substrate geometries and reduced precursor consumption, directly addressing the technical contradiction between coverage uniformity and precursor usage.
2Manufacturing precision
If a large amount of precursor per pulse is used to ensure complete coverage on complex substrates, then substrate coverage uniformity is improved, but deposition time increases
Solution Approach 1:
The dynamic flow rate adjustment allows the system to achieve complete coverage of complex substrates quickly during the high-flow initial phase, then reduces flow to minimize unnecessary deposition time. This resolves the contradiction by concentrating the coverage-enhancing flow where and when it is most needed, rather than maintaining high flow throughout the entire deposition process.
3Productivity
If simultaneous deposition on multiple parallel substrates is performed, then productivity is improved, but precursor diffusion to inner surfaces is hindered
Solution Approach 1:
The dynamic flow rate profile (high initial, then low) ensures that sufficient precursor is delivered to all surfaces including inner surfaces of stacked substrates during the critical initial phase, before the flow decreases. This resolves the contradiction by guaranteeing adequate precursor supply to hard-to-reach surfaces during the high-productivity simultaneous deposition window, then reducing flow to minimize waste.
4Manufacturing precision
If high precursor flow rate is maintained throughout the pulse, then substrate coverage is ensured, but precursor consumption increases
Solution Approach 1:
The patent resolves this contradiction by making the flow rate dynamic: high during the initial phase to ensure complete substrate coverage, then decreasing to minimize precursor consumption during the later phase when coverage is already achieved. This time-dependent adjustment allows the system to achieve both complete coverage and reduced consumption.
Solution Approach 2:
The patent changes the flow rate parameter from constant to time-varying, optimizing it for different stages of the deposition pulse. This parameter modification allows high coverage during the critical initial period while minimizing overall precursor usage, directly resolving the contradiction between coverage and consumption.
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
This approach reduces precursor consumption while ensuring uniform coverage, particularly effective for complex substrates and multiple parallel substrates, achieving low precursor usage and high coverage efficiency.
Implementation Method 1
it takes time for the ALD precursor to cover the entire surface, including the most hidden surface, of a complex substrate such as a substrate comprising deep trenches. In the case of the simultaneous deposition on a plurality of parallel substrates, the small distance between the substrates may hinder the diffusion of the precursor to surfaces within the substrates stack
Data Source
AI summary
A method and system for depositing a material on one or more substrates by atomic layer deposition. The method comprising a step of performing a pulse (1) of a precursor of said material, wherein at least one of the average flow rate (f) and the average partial pressure (r) of said precursor over a first half (2) of the pulse (1) is higher than over a second half (3) of the pulse (1).