Molecular Layer Etching of Metal-Organic Films
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Solution Overview
Problem
Current atomic layer etching (ALE) methods are limited by slow etch rates and the inability to safely and effectively remove soft materials like polymers and metal organics, posing safety concerns and restricting their use in semiconductor and microelectronic device manufacturing.
Innovation Solution
A molecular layer etching (MLE) process using a gas-phase thermal chemical method with lithium and trimethylaluminum precursors, which enables the controlled, HF-free removal of metal-organic films in a layer-by-layer fashion, achieving higher etch rates and selective etching of organic and inorganic hybrid materials.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If HF-based atomic layer etching (ALE) is used, then etching capability for metal oxides is achieved, but safety concerns arise and etch rates are limited to approximately 1 Angstrom/cycle
Solution Approach 1:
The patent changes the chemical parameters of the etching process by replacing HF-based chemistry with alternative chemistries (e.g., Cl2-based, I2-based, or organometallic precursors) that provide both safety improvements and enhanced etch rates while maintaining atomic-layer precision. This parameter substitution resolves the contradiction between safety and productivity.
Solution Approach 2:
The patent substitutes the chemical mechanism by replacing HF-based chemical reactions with alternative chemical systems that achieve etching through different reaction pathways, thereby eliminating the safety hazards of HF while maintaining or improving etching performance and rate.
2Adaptability or versatility
If traditional ALE methods are used, then metal oxide etching is achieved, but the ability to remove soft materials (polymers, metal organics) has not been demonstrated
Solution Approach 1:
The patent develops a universal etching chemistry platform that can etch multiple material types including metal oxides, polymers, and metal organics using the same atomic-layer etching approach. This multi-functionality enables the removal of soft materials while maintaining the precision and control characteristic of ALE processes.
Solution Approach 2:
The patent modifies the chemical parameters by selecting precursors and reaction conditions specifically tailored for organic and hybrid materials, enabling the etching of soft materials while maintaining atomic-layer precision through self-limiting reactions.
3Manufacturing precision
If layer-by-layer etching of soft materials is implemented, then sub-nanometer thickness control is achieved, but new fabrication techniques and processes are required
Solution Approach 1:
The patent employs self-limiting chemical reactions that automatically terminate when a monolayer is formed, providing inherent thickness control without requiring complex real-time monitoring or feedback systems. The chemistry itself serves the function of controlling the etching depth, simplifying the overall process complexity while achieving sub-nanometer precision.
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
MLE provides safer, faster etch rates (0.4-4 nm/cycle) and enables precise control over film thickness, allowing for new fabrication techniques and the use of soft materials as sacrificial layers in microelectronics and semiconductor manufacturing.
Implementation Method 1
performing an etching cycle comprising a first half reaction and a second half reaction. The first half reaction exposes a first etching precursor comprising a gaseous lithium precursor to the coating on the substrate
Implementation Method 2
The second half reaction exposes a second etching precursor, which comprises trimethylaluminum, to the coating at a second half reaction temperature
Implementation Method 3
exposes a first etching precursor comprising a gaseous lithium precursor to the coating on the substrate at a first half reaction temperature
Data Source
AI summary
A method of etching an organic or hybrid inorganic/organic material. The method etches molecular layer deposition coatings. An etching cycle comprises a first half reaction exposing the coating to a precursor. A second half reaction exposes a second precursor, removing or etching a portion of the coating.