Hybrid Atomic Layer Etching for Faster Selective Substrate Removal
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Solution Overview
Problem
Conventional atomic layer etching (ALE) techniques, including plasma ALE and thermal ALE, face challenges such as high cycle time and low throughput due to the need for high temperatures and pressures, while wet ALE, although operable at atmospheric conditions, is slow and costly due to the requirement of separate purge steps and long reaction times.
Innovation Solution
A hybrid ALE process that combines gas-phase surface modification with liquid-phase dissolution steps within the same process chamber, allowing for self-limiting reactions at near atmospheric pressure and room temperature, thereby reducing cycle time and improving throughput by eliminating the need for purge steps.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If plasma ALE or thermal ALE is used, then etching precision is improved, but cycle time increases and throughput decreases
Solution Approach 1:
The patent changes the fundamental parameters of the ALE process by operating at atmospheric pressure and room temperature instead of vacuum and high temperature conditions. This allows the use of liquid-phase chemistry with fast reaction kinetics, achieving both precise atomic-layer etching and high throughput without the need for lengthy pump-down and pump-out cycles
Solution Approach 2:
The patent replaces the plasma-based or thermal-based modification mechanisms with liquid-phase chemical reactions. The liquid reactants provide self-limiting surface modification through chemisorption, eliminating the need for complex plasma generation equipment and high-temperature heating systems, thereby reducing cycle time while maintaining etching precision
2Temperature
If wet ALE is used, then atmospheric pressure operation is achieved, but cycle time increases and throughput decreases
Solution Approach 1:
The patent optimizes the liquid-phase reaction parameters by selecting reactants with fast reaction kinetics and short residence times. The process uses rapid chemisorption reactions that complete in seconds rather than minutes, eliminating the slow reaction times that previously limited wet ALE throughput while maintaining atmospheric pressure operation
Solution Approach 2:
The patent implements a continuous flow architecture where liquid reactants are continuously delivered and removed in a streamlined manner. The process eliminates idle time between steps through continuous circulation and rapid exchange of reactant solutions, maintaining continuous useful action throughout the etching cycle to maximize throughput
3Manufacturing precision
If conventional wet ALE with separate purge steps is used, then selective dissolution is improved, but cycle time increases
Solution Approach 1:
The patent merges the dissolution step with the reactant delivery step by using a continuous flow system where fresh liquid reactants are continuously supplied. This eliminates the need for separate purge steps between modification and dissolution, as the continuous flow naturally removes reaction byproducts and supplies fresh reactants simultaneously, reducing cycle time while maintaining selective dissolution
Solution Approach 2:
The patent maintains continuous useful action by eliminating idle purge steps between modification and dissolution. The continuous flow of liquid reactants ensures that dissolution begins immediately after surface modification without interruption, keeping the system continuously productive and minimizing cycle time while preserving the selectivity of the dissolution process
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 hybrid ALE process achieves faster etching cycles and increased throughput by integrating gas-phase and liquid-phase reactions, maintaining the advantages of wet ALE while avoiding its disadvantages, with precise control over etch amount and surface roughness.
Implementation Method 1
a gas-phase reactant is used to modify an exposed surface of a material to create a modified surface layer through self-limiting reactions
Implementation Method 2
a liquid-phase reactant is used to selectively dissolve the modified surface layer through solubility-limited reactions
Data Source
AI summary
The present disclosure provides a hybrid atomic layer etching (ALE) process that combines a gas-phase surface modification step with a liquid-phase dissolution step for etching an exposed material on a substrate disposed within a process chamber. In the hybrid ALE process disclosed herein, a gas-phase reactant is used to modify an exposed surface of the material to create a modified surface layer, and one or more liquid-phase reactants are used to selectively dissolve the modified surface layer without dissolving the material underlying the modified surface layer. Once the modified surface layer is selectively dissolved, the substrate may be dried and the gas-phase surface modification and liquid-phase dissolution steps may be repeated for one or more ALE cycles until a desired amount of the material is etched.