Metal Oxide ALE Using Fluorination and Halide Removal
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Solution Overview
Problem
Existing methods for selective atomic layer etching of metal oxides are challenging due to the stability of these materials and often rely on hazardous fluorine sources like HF, which pose handling issues in manufacturing.
Innovation Solution
The proposed method involves exposing a substrate with an oxide layer to a fluorinating agent to convert a portion of the oxide layer to a fluoride layer, which is then removed using a halide etchant, thereby selectively etching the metal oxide without relying on HF.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If HF is used as the fluorine source for metal oxide etching, then etching effectiveness is improved, but safety and handling issues worsen
Solution Approach 1:
The patent replaces hazardous HF with alternative fluorine sources such as NF3, CF4, or SF6 that are less toxic and safer to handle. These alternative gases achieve comparable etching effectiveness while eliminating the severe safety and handling issues associated with HF, making the process more suitable for widespread manufacturing adoption
Solution Approach 2:
The patent changes the chemical parameters of the fluorine source from HF to alternative gases like NF3, CF4, or SF6. This parameter change maintains the etching capability while fundamentally improving safety characteristics, allowing the same etching function to be performed with much lower toxicity and handling risks
2Manufacturing precision
If selective ALE of metal oxides is achieved, then manufacturing precision is improved, but process complexity increases
Solution Approach 1:
The patent divides the etching process into two distinct sequential steps: first fluorination to convert metal oxide to metal fluoride, then removal of the fluoride layer with metal halide. This segmentation enables precise control and high selectivity for metal oxide removal while maintaining manageable process complexity through clear separation of functions
Solution Approach 2:
The patent introduces metal fluoride as an intermediate compound in the etching process. The metal oxide is first converted to metal fluoride, which then serves as the target for selective removal by metal halide. This intermediary step enables high selectivity by creating a distinct chemical state that is easily differentiated from other materials
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 method achieves selective removal of metal oxides with improved safety by using alternative fluorine sources, enhancing the selectivity and efficiency of the etching process while minimizing handling hazards.
Implementation Method 1
exposing a substrate surface having an oxide layer thereon to a fluorinating agent to convert a portion of the oxide layer to a fluoride layer
Implementation Method 2
The fluoride layer is exposed to a halide etchant to remove the fluoride layer
Data Source
AI summary
Embodiments of this disclosure provide methods for etching oxide materials. Some embodiments of this disclosure provide methods which selectively etch oxide materials over other materials. In some embodiments, the methods of this disclosure are performed by atomic layer etching (ALE). In some embodiments, the methods of this disclosure are performed within a processing chamber comprising a nickel chamber material.