Persulfuric Acid Supply System with Segmented Circulation Loops
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Solution Overview
Problem
Conventional semiconductor wafer resist stripping systems face challenges in maintaining proper flow rate distribution and producing highly concentrated persulfuric acid solutions, leading to increased cooling and reheating loads and self-decomposition issues, which necessitate multiple electrolytic cells and complicates the supply of high-performance functional solutions.
Innovation Solution
A functional solution supply system with three circulation lines: a first line for returning sulfuric acid solution to the storage tank without heating, a second line for cooling and returning it to the use side through the storage tank, and a third line for heating and returning it to the use side, allowing for independent flow rate adjustments and preventing self-decomposition of persulfuric acid.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a large number of electrolytic cells are installed to produce high-concentration persulfuric acid solution, then the persulfuric acid production capacity is improved, but the cooling load on the cooler and reheating load on the heater increase
Solution Approach 1:
The circulation system is divided into two independent loops: a first circulation loop (storage tank → electrolytic cell → cooler → storage tank) for persulfuric acid production, and a second circulation loop (storage tank → heater cleaning machine → cooler → storage tank) for cleaning operations. This segmentation allows each loop to be optimized independently, reducing the total cooling and heating loads while maintaining high persulfuric acid production capacity.
2Use of energy by stationary object
If the amount of sulfuric acid solution circulated is small, then the cooling load and reheating load are reduced, but it is impossible to maintain a proper flow rate distribution in the electrolytic cell
Solution Approach 1:
The first circulation loop is dedicated to electrolytic cell operation with sufficient flow rate to maintain proper distribution, while the second loop handles cleaning machine operations. This ensures the electrolytic cell receives adequate flow rate for reliable persulfuric acid production without requiring the entire system to circulate large amounts of solution, thus minimizing cooling and heating loads.
3Stability of the object's composition
If the sulfuric acid solution is heated to prevent self-decomposition of persulfuric acid, then the persulfuric acid stability is improved, but the cleaning machine cannot receive the functional solution in time
Solution Approach 1:
The persulfuric acid solution is prepared and stored in advance in the storage tank through the first circulation loop. When the cleaning machine requires the functional solution, it is immediately supplied through the second circulation loop without delay. The preliminary preparation allows rapid response when needed, eliminating time loss while maintaining stability through controlled storage conditions.
4Device complexity
If a one loop type system is used, then the number of pumps and valves is reduced, but the flow rate distribution in the electrolytic cell cannot be maintained when the circulation amount is small
Solution Approach 1:
The system uses two circulation loops with independent flow control, allowing each loop to be optimized for its specific function. The first loop ensures proper flow rate distribution in the electrolytic cell, while the second loop serves the cleaning machine. This segmentation maintains reliability without requiring excessive pumps and valves compared to a single-loop system.
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 configuration enables the storage of high-concentration persulfuric acid in the storage tank with reduced electrolytic cell capacity, rapid heating of the solution, and efficient supply to the cleaning machine before self-decomposition, thus maintaining high performance and reducing the number of electrolytic cells required.
Implementation Method 1
an electrolyzing apparatus (3) for electrolyzing the sulfuric acid solution
Implementation Method 2
heating means (5) for heating the sulfuric acid solution
Implementation Method 3
cooling means (4) for cooling the sulfuric acid solution
Data Source
AI summary
A sulfuric acid electrolyte is produced efficiently as a functional solution and persulfuric acid produced by electrolysis is supplied efficiently to a use side while suppressing self-decomposition thereof.A functional solution supply system adapted to electrolyze a sulfuric acid solution to prepare a functional solution and supply the functional solution to a use side, comprises a storage tank 2 for storing the sulfuric acid solution, an electrolyzing apparatus (electrolytic cell 3) for electrolyzing the sulfuric acid solution, heating means (heater 5) for heating the sulfuric acid solution, cooling means (cooler 4) for cooling the sulfuric acid solution, a first circulation line 11 for returning the sulfuric acid solution discharged from the storage tank 2 to the storage tank 2 through the electrolyzing apparatus without passing through the heating means, a second circulation line 12 for returning the sulfuric acid solution introduced from the use side (cleaning machine 1) to the use side through the cooling means and the storage tank 2 in this order without passing through the heating means, and a third circulation line 13 for returning the sulfuric acid solution introduced from the use side to the use side through the heating means (heater 5) without passing through the cooling means and the storage tank 2.