UPW Polishing System with Recirculation Loop and Pressure Control
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Solution Overview
Problem
Current ultrapure water (UPW) delivery systems struggle to effectively remove particles smaller than 20 nm, and sometimes produce particles when subjected to flow and pressure variations, which can impact semiconductor device manufacturing yields.
Innovation Solution
A water polishing system that includes an ultrafiltration (UF) module with a recirculation loop, a recirculation pump, and a pressure control valve, which maintains a constant transmembrane pressure and recirculates permeate to enhance particle removal and prevent particle generation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional UPW delivery systems are used, then the system is simple, but particles smaller than 20 nm cannot be effectively removed and particles may be generated during flow and pressure variations
Solution Approach 1:
The system divides the UPW delivery into multiple functional segments: a recirculation loop for continuous circulation, a separate pressure control mechanism for maintaining constant transmembrane pressure, and a permeate recirculation path. This segmentation allows each component to optimize its specific function while collectively achieving superior particle removal without excessive overall complexity.
Solution Approach 2:
The recirculation pump continuously circulates permeate through the UF module, maintaining constant flow through the membrane. This continuous action prevents particle generation that occurs in conventional systems during flow variations, while the closed-loop design ensures that the system operates continuously without requiring complex additional components.
2Reliability
If flow and pressure variations occur in conventional systems, then the system is easier to operate, but particles are generated which impact semiconductor manufacturing yield
Solution Approach 1:
The pressure control valve receives feedback from the permeate pressure measurement and automatically adjusts to maintain constant transmembrane pressure. This feedback mechanism prevents particle generation during flow variations without requiring complex manual operation, as the system self-regulates to maintain optimal filtration conditions.
Solution Approach 2:
The system changes the operating parameter from variable pressure to constant transmembrane pressure by using the pressure control valve. This parameter change fundamentally alters the filtration process to prevent particle generation, while the valve's automated control keeps the system easy to operate by maintaining the optimal pressure parameter without manual intervention.
3Manufacturing precision
If conventional filtration is used, then the device complexity is low, but particles as small as 10 nm cannot be removed
Solution Approach 1:
The system performs preliminary recirculation of permeate through the UF module before the water is used in semiconductor manufacturing. This preliminary action allows the filtration process to continuously remove particles as small as 10 nm from the water stream, ensuring that only ultra-pure water enters the manufacturing process without requiring complex filtration systems at the point of use.
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 achieves efficient removal of particles as small as 10 nm, maintains constant flow and pressure, reducing particle shedding and protecting the filter material, thereby improving the quality of ultrapure water for semiconductor manufacturing.
Implementation Method 1
an ultrafiltration (UF) module having an inlet and a permeate outlet
Implementation Method 2
a recirculation pump disposed along the recirculation conduit upstream from the inlet of the UF module
Implementation Method 3
a pressure control valve disposed along the recirculation conduit downstream from the supply conduit and configured to maintain a pressure of permeate at a predetermined value
Data Source
AI summary
According to various aspects and embodiments, a system and method for polishing ultrapure water (UPW) is disclosed. The water polishing system includes a source of ultrapure water (UPW), an ultrafiltration (UF) module having an inlet and a permeate outlet, a recirculation conduit communicating the permeate outlet with the inlet and forming a recirculation loop, a recirculation pump disposed along the recirculation conduit upstream from the inlet of the UF module and fluidly coupled to the source of UPW, a supply conduit fluidly coupled to the recirculating conduit and a demand source, the supply conduit positioned downstream from the permeate outlet, and a pressure control valve disposed along the recirculation conduit downstream from the supply conduit and configured to maintain pressure of permeate at a predetermined value.