Liquid Mixing Apparatus Temperature Control
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Solution Overview
Problem
The existing liquid processing apparatuses for semiconductor and FPD manufacturing face challenges in efficiently producing mixed chemical liquids containing pure water and sulfuric acid, as the exothermic reaction between sulfuric acid and water leads to increased temperatures, prolonging the cooling time and production process.
Innovation Solution
A liquid processing apparatus with a mixing tank system that includes a circulation line and a controller to manage the supply and circulation of pure water and sulfuric acid, utilizing parallel supply lines and flow rate control valves to regulate the flow rates and temperature, thereby shortening the production time of the mixed chemical liquid.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If pure water and sulfuric acid are mixed in a pre-mixing tank using a mixing pump, then the mixed chemical liquid is produced, but the temperature of the mixed solution highly increases at certain portions due to exothermic reaction, prolonging the cooling time
Solution Approach 1:
The patent applies preliminary action by first supplying pure water to the mixing tank and activating the circulation pump before supplying sulfuric acid. This ensures that water is already present and circulating when the exothermic reaction begins, allowing heat to be distributed and dissipated more effectively throughout the tank, preventing localized temperature spikes and reducing overall cooling time.
2Productivity
If sulfuric acid is concentrated on a certain portion of the pre-mixing tank, then mixing occurs, but the temperature highly increases at that portion, requiring longer cooling time
Solution Approach 1:
The patent implements feedback control by using a temperature sensor to monitor the temperature of the mixed chemical liquid and a controller to adjust the circulation pump's operation accordingly. When the temperature sensor detects elevated temperatures, the controller increases the circulation pump's operation to enhance heat distribution and dissipation, creating a closed-loop control system that dynamically responds to temperature conditions and prevents localized overheating.
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 apparatus effectively suppresses temperature increases during the exothermic reaction, reducing the cooling time and overall production time for the mixed chemical liquid, improving the efficiency and accuracy of the chemical liquid supply.
Implementation Method 1
when sulfuric acid is mixed with water, an exothermic reaction occurs. Therefore, if pure water is mixed with sulfuric acid, a temperature of the mixed solution is increased.
Implementation Method 2
a circulation line having a circulation pump configured to return the mixed chemical liquid discharged from the mixing tank back to the mixing tank
Data Source
AI summary
A liquid processing apparatus 200 includes a pure water supply source 20; a pure water flow rate control opening/closing valve 27; a sulfuric acid supply unit 30; a sulfuric acid supply opening/closing valve 34; mixing tanks 11 and 12 configured to mix pure water and sulfuric acid to produce a mixed chemical liquid and connected to a circulation line 100 having a circulation pump 101; a liquid processing unit 210 configured to perform a liquid process on a substrate W with the mixed chemical liquid. A controller 300 controls a pure water supply opening/closing valve 26, the sulfuric acid supply opening/closing valve 34, and the circulation pump 101, such that operation of the circulation pump 101 is started after starting supply of the pure water to the mixing tanks 11 and 12, and then, supply of sulfuric acid to the mixing tanks 11 and 12 is started.