Dynamic Ceramic Membrane Filtration for Wafer Wastewater Recycling
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Solution Overview
Problem
Existing wastewater treatment methods in semiconductor manufacturing processes for wafer cutting, grinding, and polishing are inefficient, requiring chemical agents that lead to secondary contamination, have low filtration accuracy, and result in unstable treatment capacity, membrane clogging, and low recycling rates of semiconductor material fine powder and water.
Innovation Solution
A recycling method using a dynamic ceramic membrane filtration system with a hydrophilic and high-stiffness ceramic membrane, combined with a cluster filter, performs in-situ dewatering and drying to achieve high-precision solid-liquid separation without chemicals, followed by ultrafiltration and reverse osmosis for high-purity water recovery.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If chemical agents are used for sedimentation treatment, then solid-liquid separation can be achieved, but secondary contamination occurs and recycling rate decreases
Solution Approach 1:
The patent extracts and removes chemical agents from the treatment process entirely, replacing them with a physical membrane filtration system. The ceramic membrane physically separates semiconductor particles from water through size exclusion, eliminating the need for chemical coagulants and flocculants that cause secondary contamination.
Solution Approach 2:
The patent replaces the chemical-based sedimentation system with a mechanical/physical membrane filtration system. The ceramic membrane uses physical pore structures to achieve separation, substituting chemical reactions with mechanical filtration at the micro-scale.
2Object-generated harmful factors
If filters are used for multi-stage filtration, then wastewater can be treated without chemical agents, but treatment capacity is limited and process length increases
Solution Approach 1:
The patent changes the critical parameter of filtration from macro-scale physical filtration to nano-scale membrane filtration. By reducing the pore size to the nanometer range and using cross-flow filtration dynamics, the system achieves high treatment capacity in a single stage rather than requiring multiple sequential filtration stages.
Solution Approach 2:
The patent employs dynamic cross-flow filtration where the feed stream continuously moves across the membrane surface, creating shear forces that prevent particle deposition and maintain high flux. This dynamic approach replaces static multi-stage filtration, increasing treatment capacity while maintaining single-stage operation.
3Measurement precision
If static membrane is used for filtration, then high filtration accuracy can be achieved, but membrane clogging occurs and flux declines sharply
Solution Approach 1:
The patent transforms the static membrane system into a dynamic cross-flow filtration system. The continuous tangential flow across the membrane surface creates shear forces that prevent particle accumulation on the membrane, eliminating clogging while maintaining high filtration accuracy through the nano-scale pore structure.
Solution Approach 2:
The patent ensures continuous filtration action by maintaining constant cross-flow across the membrane surface. This continuous dynamic action prevents particle deposition and maintains stable flux over extended operation periods, replacing the intermittent operation required by static membranes that need frequent cleaning.
4Loss of substance
If nano-sized semiconductor powder is separated from water, then resource recycling can be achieved, but the stable solid-liquid system resists separation
Solution Approach 1:
The patent changes the separation mechanism from relying on gravitational settling (which fails for stable nano-suspensions) to size-based membrane filtration. The nano-scale pore size of the ceramic membrane provides a physical size exclusion mechanism that effectively separates particles regardless of their colloidal stability, enabling resource recycling.
Solution Approach 2:
The patent extracts the separation mechanism from the bulk liquid phase and performs it at the membrane interface. By using cross-flow filtration, the separation occurs continuously at the membrane surface where the concentrated sludge layer is constantly swept away, preventing re-stabilization and enabling complete separation of the stable nano-suspension.
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 achieves a recycling rate of over 97% for wastewater and 98% for semiconductor fine particles, with stable operation and high filtration accuracy, reducing energy consumption and avoiding chemical residues.
Implementation Method 1
performing a solid-liquid separation treatment on wastewater from wafer cutting, grinding, and polishing processes through a dynamic ceramic membrane filtration system
Implementation Method 2
a separation layer of the ceramic membrane has a hydrophilicity due to a presence of titanium oxide
Implementation Method 3
performing an in-situ dewatering and drying treatment on the filter cake layer
Data Source
AI summary
The present disclosure discloses a recycling method of wastewater from wafer cutting, grinding, and polishing processes in a semiconductor manufacturing process, in which, without any chemical reagents, solid-liquid separation treatments are sequentially performed on the wastewater through a dynamic ceramic membrane filtration system and a cluster filter, and the resulting clear liquid enters a UF system and/or a RO system when being detected to be qualified, achieves the recycling of wastewater. The present disclosure further discloses a method for preparing a ceramic membrane used in the recycling method. The ceramic membrane has a hydrophilicity due to titanium oxide and a high bending stiffness due to zirconium oxide; in addition, the ceramic membrane has a high wearing resistance, a surface coating resistant to contamination and less prone to clogging, and a high filtration accuracy. The solid-liquid separation is directly performed and both solid-phased and liquid-phased targets are recycled.