Flow Distribution Plate for Semiconductor Surface Fluorine Reduction
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Solution Overview
Problem
Existing methods for reducing fluorine on semiconductor substrate surfaces, such as wet etch processes, face selectivity issues and physical deformation, and are limited as device sizes decrease, necessitating a more effective dry etch process.
Innovation Solution
A method involving a plasma process system with a flow distribution plate, where fluorine-containing precursors are mixed with oxygen and hydrogen to form hydrogen fluoride, which is then used to etch the substrate, reducing fluorine concentration to less than 2% on the surface.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If wet etch processes are used to reduce surface fluorine, then fluorine removal is achieved, but selectivity is poor and physical deformation occurs
Solution Approach 1:
The patent replaces wet etch (liquid chemical) with a dry plasma-based process using hydrogen fluoride generated in situ. This substitution eliminates the need for liquid chemicals that cause physical deformation, using instead a controlled plasma reaction that removes fluorine without compromising structural integrity or selectivity
Solution Approach 2:
The patent changes the chemical state and delivery method of fluorine removal from wet chemical etching to dry plasma-generated hydrogen fluoride. By controlling parameters such as precursor flow rates, plasma power, and chamber pressure, the process achieves selective fluorine removal while maintaining manufacturing precision
2Object-affected harmful factors
If traditional wet etch processes are used, then fluorine removal is possible, but the process reaches limitations as device sizes decrease
Solution Approach 1:
The patent substitutes wet etch with a dry plasma process that is inherently more suitable for miniaturized devices. The plasma-generated hydrogen fluoride can access and treat high-aspect-ratio structures and sub-10nm features that are inaccessible to liquid-based wet etch processes
Solution Approach 2:
The patent generates hydrogen fluoride in situ within the plasma chamber before substrate exposure, ensuring the reactive species are already formed and ready to interact with surface fluorine. This preliminary generation of etchant species enables effective treatment of miniaturized structures
3Quantity of substance
If plasma blocking screens are used to deliver fluorine precursors, then fluorine radicals are generated, but direct contact with substrate must be prevented
Solution Approach 1:
The patent introduces oxygen and hydrogen as intermediary species that react with fluorine radicals to form hydrogen fluoride. This intermediary reaction step converts highly reactive fluorine radicals into a more controlled hydrogen fluoride species that can remove surface fluorine without causing uncontrolled damage or excessive fluorine deposition
Solution Approach 2:
The patent converts potentially harmful excess fluorine radicals into beneficial hydrogen fluoride through controlled reaction with hydrogen and oxygen. The hydrogen fluoride serves as a controlled etchant that removes surface fluorine effectively while the unreacted precursors are safely exhausted without damaging the substrate
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 effectively reduces fluorine on the substrate surface while maintaining or improving etch selectivity and rate, avoiding the limitations of traditional wet etch processes.
Implementation Method 1
delivering an oxygen and hydrogen containing precursor to the volume and mixing the oxygen and hydrogen with the fluorine to form hydrogen fluoride
Implementation Method 2
generating one or more of fluorine radicals or ions, delivering the one or more of fluorine radicals or ions through one or more plasma blocking screens
Data Source
AI summary
A method and apparatus for processing a semiconductor substrate are described herein. A process system described herein includes a plasma source and a flow distribution plate. A method described herein includes generating fluorine radicals or ions, delivering the fluorine radicals or ions through one or more plasma blocking screens to a volume defined by the flow distribution plate and one of one or more plasma blocking screens, delivering oxygen and hydrogen to the volume, mixing the oxygen and hydrogen with fluorine radicals or ions to form hydrogen fluoride, flowing hydrogen fluoride through the flow distribution plate, and etching a substrate using bifluoride. The concentration of fluorine radicals or ions on the surface of the substrate is reduced to less than about two percent.