Filter Cleaning Sequence Using DIW and IPA for Membrane Wetting
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Solution Overview
Problem
Existing filter cleaning methods in substrate liquid processing apparatuses are inadequate for effectively removing contaminants before use, leading to potential contamination of processing liquids.
Innovation Solution
A filter cleaning system utilizing a combination of deionized water (DIW) and isopropyl alcohol (IPA) with controlled decompression and circulation paths to clean filters, where DIW removes metal components and IPA removes other contaminants, ensuring thorough filtration membrane wetting and degassing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If high-temperature pure water and low-temperature pure water are alternately supplied to clean the filter, then the cleaning process is simple, but the cleaning effectiveness is insufficient for removing all types of contaminants
Solution Approach 1:
The cleaning process is segmented into multiple stages using different cleaning liquids with specific functions: a first cleaning liquid (surfactant-based) for wetting and removing hydrophobic contaminants, a second cleaning liquid (organic solvent) for removing metal components and hydrophilic contaminants, and a third cleaning liquid (pure water) for final rinsing. Each stage targets specific contaminant types, comprehensively solving the limitation of single-method cleaning.
Solution Approach 2:
The invention changes the chemical parameters of the cleaning medium by using different liquids with specific properties (surface tension, solubility parameters, hydrophobicity/hydrophilicity) for different cleaning stages. This allows optimization of cleaning effectiveness for different contaminant types while maintaining operational simplicity through automated sequential delivery.
2Ease of operation
If a single cleaning liquid is used to clean the filter, then the cleaning process is simple, but it cannot remove all types of contaminants effectively
Solution Approach 1:
The cleaning system segments the cleaning function across multiple liquids: the first cleaning liquid (surfactant solution) handles wetting and hydrophobic contaminant removal, the second cleaning liquid (organic solvent like alcohol) handles metal components and hydrophilic contaminants, and the third cleaning liquid (pure water) handles final rinsing. This segmentation enables comprehensive contaminant removal while the automated sequential delivery maintains operational simplicity.
Solution Approach 2:
The first cleaning liquid acts as an intermediary that prepares the filter surface by wetting it and removing hydrophobic contaminants, creating a surface that is then effectively treated by the second cleaning liquid. This intermediary step enables the subsequent liquids to work more effectively, achieving complete contaminant removal through coordinated action of multiple substances.
3Loss of time
If the filter is not thoroughly cleaned before use, then the apparatus can be used immediately, but processing liquids become contaminated over time
Solution Approach 1:
The system performs preliminary cleaning actions using multiple specialized cleaning liquids before the filter is put into service. The sequential cleaning process with surfactant, organic solvent, and pure water thoroughly removes all types of contaminants including metal components, hydrophobic substances, and hydrophilic substances, ensuring the filter is completely clean before contact with processing liquids, thus preventing long-term contamination.
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 system effectively cleans filters by removing a wide range of contaminants, including metal components, thereby preventing long-term contamination of processing liquids and maintaining filtration efficiency.
Implementation Method 1
a second liquid having a surface tension lower than that of the first liquid and an affinity for the first liquid
Implementation Method 2
the second liquid having a surface tension lower than that of the first liquid and an affinity for the first liquid
Implementation Method 3
The circulation path returns the liquid sent from the filter to the storage unit
Data Source
AI summary
A filter cleaning system includes a storage unit that stores liquid that is passed through a filter; a liquid supply path that sends the liquid stored in the storage unit to the filter; a circulation path that returns the liquid sent from the filter to the storage unit; a first supply unit that supplies a first liquid to the storage unit; and a second supply unit that supplies a second liquid having a surface tension lower than that of the first liquid and an affinity for the first liquid, to the storage unit.