Resist Charging Apparatus Pressure Fluctuation Control
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Solution Overview
Problem
Existing charging apparatuses for resist liquids experience pressure fluctuations across filters due to opening and closing of charging valves, which can cause impurities to pass through and contaminate the downstream side during the charging operation.
Innovation Solution
A charging apparatus with a collecting passage and valves that reflux the liquid back to the tank, a feed pump, and a controlling unit to manage the opening of valves, ensuring pressure stability across the filter by controlling the degree of opening of the collecting valve based on sensed pressures and pre-defined relationships.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a filter is used to remove impurities from resist liquid, then filtering accuracy is improved, but pressure fluctuation occurs during charging operations causing impurities to pass through
Solution Approach 1:
The patent applies dynamics by making the collecting valve adjustable rather than fixed. The degree of opening of the collecting valve can be dynamically changed based on operational requirements, allowing the system to adapt to different charging conditions while maintaining pressure stability across the filter.
Solution Approach 2:
The patent changes the parameter of valve opening degree to control pressure fluctuations. By adjusting the degree of opening of the collecting valve, the system maintains a substantially constant pressure difference across the filter during charging operations, preventing impurities from passing through while maintaining filtering accuracy.
2Reliability
If the degree of opening of the collecting valve is adjusted to maintain pressure stability, then pressure fluctuation is reduced, but valve control complexity increases
Solution Approach 1:
The patent implements feedback control where the degree of opening of the collecting valve is adjusted based on the charging amount. As the charging progresses and pressure conditions change, the valve opening degree is automatically modified to maintain stable pressure across the filter, creating a self-regulating system.
Solution Approach 2:
The system performs self-adjustment through the automatic modification of the collecting valve opening degree based on charging conditions. The control mechanism uses the charging state information to automatically regulate the valve, reducing the need for external intervention while maintaining pressure stability.
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 effectively reduces pressure fluctuations across the filter, enhancing the accuracy of filtering the resist liquid and preventing impurities from passing through, thereby improving the overall filtering process.
Implementation Method 1
a feed pump that is provided in the charging liquid passage and delivers the charging liquid in the charging liquid tank
Implementation Method 2
a filter that is provided between the feed pump and the branch portion in the charging liquid passage
Implementation Method 3
pressure sensing units in the upstream side and the downstream side of the filter
Data Source
AI summary
Intended is to reduce pressure fluctuations across a filter (14) for filtering a resist liquid. A charging apparatus is provided including a charge liquid tank (2) of resist liquid, a feed pump (10), a charge nozzle (8), a recovery passage (16), a recovery valve (20) disposed in the recovery passage (16), the filter (14), and a control device (24) for controlling the servomotors to adjust the openings of the charge valve (12) and the recovery valve (20) so that the pressures on the upstream side and the downstream side of the filter (14) may not fluctuate.