Hydrogen Fluoride Distillation with F2 Oxidation for AsF3 Removal
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Solution Overview
Problem
Existing methods for producing ultra-high purity hydrogen fluoride are costly and inefficient, particularly due to the difficulty in removing arsenic trifluoride (AsF3) impurities, which affect semiconductor production quality and increase environmental waste generation.
Innovation Solution
A method and apparatus that utilize a multi-stage distillation process with a gas stream containing F2 gas and an inert gas to oxidize and remove AsF3 impurities, controlled by an advanced process control module, allowing continuous production of ultra-high purity hydrogen fluoride without a pretreatment process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a pretreatment process is performed to remove impurities before production, then impurity removal is improved, but device complexity and process cost increase
Solution Approach 1:
The patent combines the pretreatment process and main production process into a single integrated distillation column. The pretreatment section and main production section share the same column structure, eliminating the need for separate pretreatment apparatus and simplifying the overall process while maintaining effective impurity removal
Solution Approach 2:
The distillation column serves multiple functions simultaneously: it performs pretreatment to remove major impurities, conducts main production through fractional distillation, and enables continuous operation. This multi-functional design reduces device complexity by eliminating separate pretreatment equipment
2Productivity
If multiple distillation columns are used for continuous production, then productivity is improved, but device complexity increases
Solution Approach 1:
The distillation column is segmented into multiple functional sections: pretreatment section, main production section, and fractionation section. Each section handles specific impurities or production tasks, enabling continuous operation while maintaining a single-column structure that avoids the complexity of multiple separate columns
Solution Approach 2:
The patent implements dynamic control of reflux ratio and heating vapor flow rates to optimize separation efficiency throughout the column. This dynamic operation allows a single column to perform the work of multiple static columns, improving productivity without proportionally increasing device complexity
3Manufacturing precision
If F2 gas is injected to oxidize AsF3 impurities, then manufacturing precision is improved, but loss of substance and cost increase
Solution Approach 1:
F2 gas is injected at specific locations within the distillation column where AsF3 impurities are most concentrated, rather than uniformly throughout. This localized oxidation approach maximizes impurity removal efficiency while minimizing F2 gas consumption and associated hydrogen fluoride loss
Solution Approach 2:
The system monitors impurity levels and adjusts F2 gas injection rates accordingly. This feedback control ensures that oxidation is applied only where and when needed, preventing excessive F2 consumption and hydrogen fluoride loss while maintaining effective arsenic fluoride removal
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 method enables efficient, continuous production of ultra-high purity hydrogen fluoride with reduced costs and improved production efficiency, minimizing impurities to ppt or ppq levels, suitable for semiconductor and display applications.
Implementation Method 1
performing a continuous distillation process of supplying crude hydrogen fluoride to a multi-stage distillation column to extract and remove impurities in the distillation column after fractional distillation
Implementation Method 2
injecting a gas stream containing an F2 gas and an inert gas for removal of AsF3 in impurities into the multi-stage distillation column
Data Source
AI summary
The present invention discloses a method and apparatus for purifying ultra-high purity hydrogen fluoride, which purify it through a continuous distillation process by putting crude hydrogen fluoride instead of hydrogen fluoride into a multi-stage distillation column as it is, and remove impurities in hydrogen fluoride through a contact with fluorine gas having the concentration of the F2 gas automatically controlled depending on the content of arsenic fluoride that is an impurity.