High-Purity Ethylenediamine Purification for Semiconductor Processing
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Solution Overview
Problem
Conventional methods for producing anhydrous ethylenediamine (EDA) result in products with high residual water content and impurities, making them unsuitable for semiconductor processing due to contamination risks and corrosion issues.
Innovation Solution
The process involves passing EDA through a 3A molecular sieve to remove water, followed by distillation to remove metallic impurities, and storing the purified EDA in pre-treated containers to reduce corrosion and maintain purity over time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional fractional distillation is used to remove water from EDA, then the dehydration process is simple, but it is impossible to achieve adequate water removal due to the high-boiling azeotrope forming about 15% water by weight
Solution Approach 1:
The patent introduces molecular sieves (5A or 13X type) as an intermediary substance to selectively adsorb water from EDA. The molecular sieves act as a mediator that preferentially binds water molecules while allowing EDA to pass through, thereby breaking the azeotropic limitation and enabling water removal to below 50 ppm levels.
Solution Approach 2:
The patent employs porous molecular sieve materials with specific pore sizes (5A or 13X type) that selectively adsorb water molecules based on their size and polarity. The porous structure allows differential penetration where water is trapped in the pores while EDA molecules pass through, achieving effective dehydration despite the azeotropic composition.
2Ease of manufacture
If EDA is synthesized in the presence of water, then the synthesis process is simpler, but the product contains high water content that must be removed for semiconductor applications
Solution Approach 1:
The patent extracts water from the EDA product using molecular sieves after synthesis. The molecular sieves selectively remove water molecules from the EDA solution, separating the harmful water component from the desired EDA product and achieving the required purity for semiconductor applications.
Solution Approach 2:
Molecular sieves serve as an intermediary agent that facilitates water removal without requiring complex distillation equipment or additional chemical reactions. The sieves mediate the separation process by selectively adsorbing water while allowing EDA to remain in the solution.
3Manufacturing precision
If conventional methods using water entrainers like benzene are used to break the azeotrope, then water content can be reduced below 0.5%, but residual entrainer impurities remain making the product unsuitable for semiconductor processing
Solution Approach 1:
The patent uses disposable molecular sieve cartridges that can be replaced when saturated. Unlike conventional entrainers that require complex recycling systems, the molecular sieves are used once and then discarded or regenerated, eliminating residual entrainer impurities in the product while achieving the required water removal.
Solution Approach 2:
The molecular sieve porous material selectively adsorbs water molecules while allowing EDA to pass through without interaction. This selective adsorption based on pore size and molecular affinity removes water to below 50 ppm without leaving any residual organic entrainer impurities in the product.
4Ease of manufacture
If EDA is stored in conventional containers, then storage is simple, but corrosion and contamination occur over time due to water and metallic impurities
Solution Approach 1:
The patent stores EDA in containers purged with inert gas (nitrogen or argon) to create an oxygen-free, moisture-resistant atmosphere. This inert environment prevents oxidation and contamination of the high-purity EDA while minimizing corrosion of container materials, maintaining purity over extended storage periods.
Solution Approach 2:
The patent introduces aluminum oxide or other inert barrier materials as intermediaries between the EDA and container walls. These materials form a protective layer that prevents direct contact between EDA and metallic container surfaces, thereby preventing corrosion and metal ion contamination while allowing storage in conventional containers.
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 EDA with water levels below 50 ppm and trace metal impurities below 100 ppb, significantly reducing corrosion and contamination risks, thereby making the EDA suitable for long-term storage and use in semiconductor processing.
Implementation Method 1
passing EDA through a 3A molecular sieve to remove water
Implementation Method 2
followed by distillation to remove metallic impurities
Data Source
AI summary
A method for making the EDA that is suitable for use in thin-film semiconductor processing applications, are disclosed. The EDA is purified to remove water and trace metals. Water levels below about 50 ppm by weight are achieved by passing liquid through 3A type molecular sieve in a packed bed. Metallic impurities are removed by distillation and the resulting product is packaged in specially dried and optionally pre-conditioned containers.