Polyimide Membrane Purification for Semiconductor Fluids
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Solution Overview
Problem
Conventional porous membranes used in semiconductor manufacturing, such as those made of nylon and polyethylene, face challenges including poor acid resistance, low impurity removal rates, and reduced durability under increased flow rates, making it difficult to balance impurity removal capability with flow rate and durability.
Innovation Solution
A polyimide and/or polyamideimide porous membrane with interconnected pores is used, maintaining high stress resistance and fracture elongation while effectively removing metals, even at increased flow rates, by utilizing a differential pressure method for liquid purification.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional porous membranes (nylon, polyethylene) are used for impurity removal, then metal removal capability is achieved, but acid resistance and durability are poor
Solution Approach 1:
The patent changes the material parameter from conventional porous membranes to a specific polyimide composition with controlled molecular weight (intrinsic viscosity 0.4-1.5 dL/g) and chemical structure (containing rigid aromatic rings and imide groups), achieving both high metal removal capability and excellent acid resistance
Solution Approach 2:
The patent creates a composite structure by combining polyimide polymer matrix with controlled porous morphology, achieving synergistic effects where the polyimide provides chemical stability and the porous structure provides filtration capability
2Productivity
If flow rate is increased to improve productivity, then purification speed increases, but impurity removal capability and membrane durability decrease
Solution Approach 1:
The patent utilizes a porous polyimide membrane with specific pore structure that allows high flow rates while maintaining filtration efficiency through the inherent properties of the porous network and polyimide material strength
Solution Approach 2:
The patent employs curved pore structures rather than straight channels, which reduces flow resistance and allows higher flow rates while maintaining effective contact between liquid and membrane filtration surfaces
3Productivity
If flow rate is increased to improve productivity, then purification speed increases, but membrane stress resistance and fracture elongation decrease
Solution Approach 1:
The patent optimizes the intrinsic viscosity parameter of polyimide to 0.4-1.5 dL/g, which controls the molecular weight and chain entanglement, providing adequate mechanical strength to withstand high flow rates without membrane rupture
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 polyimide and/or polyamideimide porous membrane achieves a high metal removal rate while maintaining a balanced flow rate and mechanical properties, enhancing the purification efficiency and durability of the filtration process.
Implementation Method 1
allowing part or all of the liquid to be passed thorough from one side to the other side of a polyimide and/or polyamideimide porous membrane having interconnected pores by way of a differential pressure
Data Source
AI summary
The present invention addresses the problem of providing: a method for purifying a liquid using a porous polyimide and/or polyamideimide membrane having excellent impurities (e.g., metals) removal performance which is preferably compatible with a flow rate, and also having an excellent stress, an excellent breaking elongation and the like; a method for producing a chemical solution or a cleaning solution employing the purification method; a filter medium comprising the porous membrane; and a filter device equipped with the porous membrane. A method for purifying a liquid, comprising causing a portion or the whole of the liquid to pass through a porous polyimide and/or polyamideimide membrane having communicated pores from one side of the membrane to the other side of the membrane by the action of a differential pressure between the two sides.