Functional Water Apparatus Pressure Control for Wafer Washing
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Solution Overview
Problem
The existing gas dissolving devices for producing functional water fail to maintain a stable supply pressure, leading to insufficient washing of large silicon wafers, particularly those with diameters of 200 mm or more, due to fluctuations in ultrapure water supply pressure and flow rate across multiple points of use.
Innovation Solution
A functional water producing apparatus that includes a pressure regulating valve and a feed water pump to maintain a constant water pressure, along with a control device that adjusts the pump's operation based on measured water pressure or flow rate to ensure a stable supply pressure, using a combination of a pressure reducing valve and a feed water pump to buffer pressure fluctuations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If ultrapure water is supplied to multiple points of use through a reflux pipe system, then the water distribution network can serve multiple washing apparatuses, but the supply pressure fluctuates when washing cycles are stopped or started simultaneously
Solution Approach 1:
The water supply system is segmented into multiple independent pressure control zones, with each washing apparatus equipped with its own pressure control valve. This segmentation isolates pressure fluctuations at one point of use from affecting other points of use, allowing multiple apparatuses to operate independently without mutual interference.
Solution Approach 2:
Pressure sensors are installed at each point of use to detect actual water pressure in real-time. The detected pressure information is fed back to the control unit, which automatically adjusts the pressure control valve to maintain stable supply pressure, compensating for fluctuations caused by simultaneous start-stop operations of washing cycles.
2Device complexity
If the supply pressure of ultrapure water is kept almost constant in the reflux pipe system, then pressure distribution to multiple points of use is simplified, but downstream points cannot compensate for upstream pressure changes
Solution Approach 1:
Instead of maintaining uniform pressure control throughout the entire reflux pipe system, each point of use is equipped with local pressure control valves and sensors. This allows each downstream apparatus to independently adjust and compensate for pressure changes, ensuring reliable supply pressure at each specific location regardless of upstream fluctuations.
Solution Approach 2:
Pressure control valves are pre-configured at each point of use to automatically respond to pressure changes before they affect washing quality. The system proactively maintains pressure stability rather than reactively correcting problems, ensuring consistent supply pressure even during simultaneous start-stop operations.
3Area of stationary object
If large-sized silicon wafers (200 mm diameter or more) are washed by pouring functional water, then washing coverage is improved, but insufficient washing occurs when supply pressure decreases
Solution Approach 1:
Pressure sensors monitor the supply pressure of functional water in real-time during washing operations. When pressure decreases that could compromise washing quality of large wafers, the control unit receives feedback and automatically adjusts pressure control valves to restore adequate pressure, ensuring consistent washing quality across the entire wafer surface.
Solution Approach 2:
The system dynamically adjusts pressure parameters based on wafer size and washing conditions. For large-sized wafers requiring pouring washing method, the control unit increases supply pressure to ensure sufficient functional water flow and coverage, while for smaller wafers it maintains appropriate pressure levels to prevent over-washing or damage.
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
This solution stabilizes the supply pressure of functional water, preventing fluctuations and ensuring sufficient washing, even when the supply pressure of ultrapure water fluctuates, thereby addressing the insufficiency in washing large silicon wafers.
Implementation Method 1
a pressure regulating valve configured to regulate a water pressure of the ultrapure water to an almost constant pressure
Implementation Method 2
a feed water pump configured to pressurize the ultrapure water
Implementation Method 3
a dissolving device configured to dissolve functional gas imparting a specific function in the ultrapure water regulated the water pressure by the water pressure regulator
Data Source
AI summary
A functional water producing apparatus in an embodiment includes: a water pressure regulator configured to regulate the water pressure of the ultrapure water, the water pressure regulator having a pressure regulating valve configured to regulate a water pressure of the ultrapure water to an almost constant pressure and a feed water pump configured to pressurize the ultrapure water; a dissolving device configured to dissolve functional gas imparting a specific function in the ultrapure water regulated the water pressure by the water pressure regulator; and a control device configured to control the feed water pump to regulate the water pressure of the functional water to a predetermined constant pressure based on a water pressure or a flow rate of the functional water flowing out of the dissolving device.