Cleaning Water Supply Device Solute Concentration Control
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Solution Overview
Problem
Existing cleaning water supply systems for semiconductor wafers struggle to maintain stable solute concentrations during fluctuating flow rates in multi-chamber single-wafer cleaning machines, leading to deviations in water quality and excessive water discharge.
Innovation Solution
A cleaning water supply device with a fixed ultrapure water line and solute addition system, along with a removal unit using ion exchange resin or platinum nano colloid supported resin, ensures accurate and stable solute concentration in cleaning water, preventing excess water discharge.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If cleaning water is continuously supplied at maximum flow rate to maintain stable solute concentration, then solute concentration stability is improved, but excess water discharge increases
Solution Approach 1:
The system dynamically adjusts the ultrapure water supply flow rate to match the actual cleaning water consumption in real-time. The flow rate control unit receives flow rate information from the flow rate detection unit and adjusts the ultrapure water supply accordingly, enabling the system to adapt to varying demand while maintaining stable solute concentration and preventing excess water discharge.
Solution Approach 2:
The system implements a feedback control mechanism where the flow rate detection unit continuously monitors the cleaning water flow rate, and this information is fed back to the flow rate control unit. The control unit uses this feedback to adjust the ultrapure water supply, ensuring that the solute concentration remains stable while minimizing water waste by supplying only the necessary amount.
2Measurement precision
If solute adding control is performed by proportional control or PID control to maintain desired concentration, then concentration accuracy is improved, but the system cannot sufficiently follow irregular flow rate fluctuation
Solution Approach 1:
The system replaces traditional mechanical control methods (proportional control, PID control) with a direct measurement and adjustment approach. Instead of using complex control algorithms that struggle with irregular fluctuations, the system directly measures the actual flow rate and adjusts the solute addition accordingly, providing more reliable response to irregular flow rate changes while maintaining concentration accuracy.
Solution Approach 2:
The system performs preliminary measurement of the cleaning water flow rate before adjusting the solute addition. By detecting the flow rate in advance and using this information to control the solute supply, the system can proactively maintain the desired concentration even when flow rate fluctuations occur irregularly, rather than reacting after deviations have occurred.
3Ease of operation
If chemical solution injection method is used to produce cleaning water, then operation simplicity is improved, but solute concentration control becomes difficult when flow rate fluctuates irregularly
Solution Approach 1:
The system enables self-service operation where the cleaning water supply device automatically detects its own flow rate and adjusts its solute addition accordingly. The flow rate detection unit and flow rate control unit work together to autonomously maintain the desired solute concentration without requiring external intervention or complex control systems, preserving operational simplicity while improving concentration control.
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 device maintains precise solute concentrations in cleaning water, reducing water waste and ensuring consistent quality, even with irregular valve operations in multi-chamber machines, by removing excess solutes efficiently and reusing ultrapure water.
Implementation Method 1
a removal unit that removes a solute from excess cleaning water from the cleaning water line
Data Source
AI summary
A cleaning water supply device includes an ultrapure water line through which ultrapure water flows by a fixed amount, a production unit that produces cleaning water by adding a solute to the ultrapure water line by a fixed amount, a cleaning water line for causing the cleaning water to flow, cleaning machines to which the cleaning water is supplied from the cleaning water line, a solute removal unit into which excess cleaning water is introduced from the cleaning water line, and a collecting line for returning collected water from which the solute is removed to a tank and the like.