Atomic Layer Etching via Localized Substrate Heating
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Solution Overview
Problem
In the field of semiconductor and display processing, existing atomic layer deposition techniques face inefficiencies due to the need for optimal reaction conditions that often differ for different reactant gases, and these conditions can cause damage to substrates if maintained for too long, especially as device geometries shrink and aspect ratios increase.
Innovation Solution
The method involves exposing a substrate to a reactant gas at a first temperature to form an etch layer, removing unreacted gas, elevating the substrate temperature to vaporize the etch layer, and then cooling it back to the original temperature, using thermal elements like radiative or resistive heating to locally control temperature changes, allowing for efficient and damage-minimized processing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the temperature is elevated to optimize reaction conditions for vaporizing the etch layer, then the etching efficiency is improved, but the substrate may suffer from thermal damage
Solution Approach 1:
The patent applies local heating to specific regions of the substrate surface where etching is required, rather than heating the entire substrate uniformly. This allows the etch layer to be vaporized efficiently at the heated locations while the rest of the substrate remains at a lower, safe temperature that prevents thermal damage.
Solution Approach 2:
The patent employs periodic temperature cycling where the substrate temperature is temporarily elevated to the etch point only during the etching step, then reduced to a safe storage temperature between etching operations. This periodic heating/cooling cycle enables efficient etching while protecting the substrate from sustained thermal exposure.
2Productivity
If the chamber temperature is changed between reactions to optimize reaction conditions, then the reaction efficiency is improved, but the process time and energy consumption increase
Solution Approach 1:
The patent maintains the bulk chamber and substrate at a constant low temperature while applying localized heating only to the specific reaction zone where etching occurs. This eliminates the need to heat the entire chamber between reactions, significantly reducing temperature change time and energy consumption while maintaining optimal reaction conditions at the etching location.
Solution Approach 2:
The patent segments the heating function by separating the bulk substrate/chamber temperature control from the localized reaction zone heating. This allows independent optimization of each zone - the bulk remains cool for stability while the reaction zone reaches etch point temperatures only when needed.
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 enables more precise and efficient material deposition by optimizing reaction conditions without long-term substrate damage, improving conformal deposition on small, high-aspect-ratio features.
Implementation Method 1
The temperature of the substrate surface is elevated to a second temperature to vaporize the etch layer from the substrate surface
Implementation Method 2
using thermal elements like radiative or resistive heating to locally control temperature changes
Implementation Method 3
using thermal elements like radiative or resistive heating to locally control temperature changes
Data Source
AI summary
Provided are methods of etching a substrate using atomic layer deposition apparatus. Atomic layer deposition apparatus including a gas distribution plate with a thermal element and remote plasma are discussed. The thermal element is capable of locally changing the temperature of a portion of the surface of the substrate to vaporize an etch layer deposited on the substrate.