Treatment Solution Supply Apparatus Feedback Control
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Solution Overview
Problem
Existing treatment solution supply apparatuses face challenges in stabilizing the dispense amount of TMAH solution due to clogging issues, leading to inefficient recycling and increased costs, particularly in the low revolution frequency region and requiring costly inverter solutions.
Innovation Solution
A treatment solution supply apparatus with a flow meter that integrates the discharge amount and provides a feedback system to adjust the pump's revolution frequency, allowing for stable dispensing regardless of filter clogging, using a servo motor and electromagnetic flow meter for precise control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional pump with fixed revolution frequency is used, then the device complexity is low, but the dispense amount becomes unstable due to filter clogging and foreign matters
Solution Approach 1:
The patent implements a feedback control system where the revolution frequency of the pump is automatically adjusted based on the discharge amount detected by the flow meter. The control device receives signals from the flow meter and modifies the pump speed to maintain a predetermined discharge amount, thereby compensating for filter clogging and ensuring stable dispense amount without requiring complex manual intervention.
2Productivity
If the pump revolution frequency is increased to improve discharge amount, then the productivity increases, but the manufacturing precision deteriorates due to overshooting of the dispense amount
Solution Approach 1:
The feedback control system continuously monitors the discharge amount and adjusts the pump revolution frequency in real-time. When the discharge amount approaches the target value, the system automatically reduces the pump speed to prevent overshooting, thereby maintaining both high productivity and precise dispense amount control.
Solution Approach 2:
The system dynamically adjusts the pump revolution frequency based on actual discharge conditions rather than operating at a fixed speed. This dynamic control allows the system to optimize discharge amount while preventing overshooting, achieving both high productivity and manufacturing precision.
3Manufacturing precision
If an inverter with peak frequency control is used, then the manufacturing precision improves, but the loss of energy increases in the low revolution frequency region
Solution Approach 1:
The system changes the operating parameters (revolution frequency) of the pump based on actual process conditions rather than using fixed peak frequency control. By dynamically adjusting the frequency to match the required discharge amount, the system achieves precise control while avoiding unnecessary energy consumption in low frequency regions where conventional inverters suffer from efficiency losses.
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 dispense amount, reduces waste, and shortens the treatment period, enabling cost-effective and efficient recycling of TMAH solution, while preventing overshooting and ensuring consistent film application from 1 mm to 3 mm thickness.
Implementation Method 1
an electromagnetic flow meter for measuring the discharge amount
Implementation Method 2
the revolution frequency of the pump is varied by the discharge amount from the nozzle
Data Source
AI summary
A treatment solution supply apparatus capable of reducing an initial overshooting amount and ensuring a stable dispense characteristic even when treating a large amount of substrates as recycling a developing solution for a large amount of substrates includes a flow meter having an integration function in the vicinity of a nozzle and carries out feedback to the pump revolution frequency control in response to a variation of the flow meter, so that a fixed amount of a solution may be regularly discharged irrespective of the clogging level of a filter. Also, a developing solution can be stably dispensed on a resist coated film within a solution applicable range from a minimum value (film thickness of 1 mm) to a maximum value (3 mm).