Coolant pH Control via Inert Gas Purging
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Solution Overview
Problem
Current coolants used in substrate processing equipment, such as distilled water, suffer from pH and resistivity inconsistencies due to carbon dioxide reaction, leading to metal corrosion and potential overheating and damage in heat exchangers.
Innovation Solution
Introducing an inert purge gas, like nitrogen, into the coolant supply reservoir to remove CO2 and maintain the coolant's pH and conductivity within optimal ranges, using deionized water and a water-soluble base like sodium hydroxide, and ensuring the coolant is slightly basic to prevent corrosion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If distilled water is used as coolant in heat exchanger, then cooling function is provided, but pH and resistivity become inconsistent leading to metal corrosion
Solution Approach 1:
The patent introduces an inert purge gas (nitrogen or argon) into the coolant system to displace carbon dioxide and create an inert atmosphere. This prevents CO2 from dissolving in the coolant and forming carbonic acid, thereby maintaining stable pH levels and preventing metal corrosion while preserving the cooling function
Solution Approach 2:
The patent modifies the chemical parameters of the coolant by adding a water-soluble base (such as sodium hydroxide or potassium hydroxide) to adjust and stabilize the pH level. This parameter change ensures the coolant remains alkaline, preventing corrosion of metal components while maintaining effective heat exchange
2Object-affected harmful factors
If coolant pH is increased to prevent corrosion, then metal corrosion rate decreases, but coolant basicity increases which may cause other issues
Solution Approach 1:
The patent implements a feedback mechanism by continuously monitoring coolant pH levels and automatically adjusting the addition of water-soluble base or the flow rate of inert purge gas. This closed-loop control maintains pH within the optimal range (8-10), preventing both corrosion and excessive basicity that could cause other problems
Solution Approach 2:
The patent establishes continuous circulation of coolant through the heat exchanger and continuous purging with inert gas to maintain stable chemical conditions. This continuous action ensures consistent pH and resistivity levels, preventing corrosion while avoiding the pitfalls of intermittent adjustment
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 method effectively maintains the coolant's pH and conductivity within desired specifications, reducing metal corrosion and extending the lifespan of processing chamber components by preventing overheating and damage.
Implementation Method 1
introducing an inert purge gas into a supply reservoir containing a coolant to form a treated coolant
Implementation Method 2
The pH of distilled water tends to be low (acidic, due to reaction with carbon dioxide (CO2) in the air)
Implementation Method 3
flowing the treated coolant to a processing chamber component to cool the processing chamber component
Data Source
AI summary
Implementations described herein generally relate to substrate processing equipment and more particularly to methods and compositions for temperature control of substrate processing equipment. In one implementation, a method of cooling a processing chamber component is provided. The method comprises introducing an inert purge gas into a supply reservoir containing a coolant and flowing the treated coolant to a processing chamber component to cool the processing chamber component. The coolant initially comprises deionized water and a water-soluble base.