pH-Adjusted Ultrapure Water Line With Degassing for Static Control
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Solution Overview
Problem
Existing technologies fail to effectively eliminate dissolved gases and control pH in ultra-pure water used for semiconductor cleaning, leading to issues like static electricity and electrostatic damage due to dissolved oxygen and hydrogen peroxide, and lack of precise pH control.
Innovation Solution
A pH-adjusted water production device incorporating a platinum group metal support resin column, membrane-type degassing device, and pH adjuster injection, followed by inert gas dissolution, to eliminate dissolved gases and achieve precise pH control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If ultra-pure water with high specific resistance is used for cleaning, then cleaning effectiveness is improved, but static electricity occurs due to corrosion of wiring metal by hydrogen peroxide
Solution Approach 1:
The patent changes the pH parameter of the ultra-pure water by adding acids or bases to adjust it to a specific range (pH 2-10). This parameter change prevents the corrosion of wiring metal by hydrogen peroxide, thereby eliminating static electricity generation while maintaining cleaning effectiveness.
Solution Approach 2:
The patent applies preliminary anti-action by adjusting the pH before cleaning operations to prevent the harmful effect of static electricity. By pre-adjusting the chemical environment (pH level), the corrosion of wiring metal is prevented before it can occur, thus avoiding static electricity generation during the cleaning process.
2Object-affected harmful factors
If pH is adjusted by adding chemicals to ultra-pure water, then static electricity problems are addressed, but dissolved gas species including oxygen cannot be eliminated
Solution Approach 1:
The patent segments the water treatment process into two independent stages: first adjusting the pH to prevent static electricity, then separately removing dissolved gases including oxygen through degassing equipment. This segmentation allows both objectives to be achieved without interfering with each other.
Solution Approach 2:
The patent uses an intermediary degassing process between pH adjustment and the cleaning operation. The degassing equipment acts as an intermediary step that removes dissolved oxygen and other gases from the pH-adjusted water, preventing both static electricity and oxygen-related issues.
3Quantity of substance
If dissolved oxygen is present in ultra-pure water, then oxygen can be eliminated through degassing, but pH control becomes difficult when chemicals are added
Solution Approach 1:
The patent applies preliminary action by removing dissolved gases including oxygen through degassing before the pH adjustment process. This preliminary degassing prevents gas interference during subsequent pH measurement and adjustment, ensuring accurate pH control when chemicals are added.
Solution Approach 2:
The patent maintains continuous control by implementing both degassing and pH adjustment as ongoing processes. The system continuously removes dissolved gases and simultaneously maintains precise pH control through automated chemical addition and monitoring, ensuring both objectives are met throughout the cleaning operation.
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
Produces high-purity, pH-adjusted water with reduced dissolved oxygen and stable pH, minimizing electrostatic risks and ensuring high cleanliness standards for semiconductor processing.
Implementation Method 1
a small amount of hydrogen peroxide included in the ultra-pure water is eliminated by passing the ultra-pure water through a platinum group metal support resin column
Implementation Method 2
the water is degassed by a membrane-type degassing device to eliminate dissolved oxygen in the pH-adjusted water
Implementation Method 3
pH adjustment has been performed by adding chemicals such as carbon dioxide, ammonia, or the like, to ultra-pure water
Data Source
AI summary
A pH-adjusted water production device has a configuration in which a platinum group metal support resin column, a membrane-type degassing device, and a gas dissolving membrane device are provided on an ultra-pure water supply line, and a pH-adjuster injection device is provided between the platinum group metal support resin column and the membrane-type degassing device. An inert gas source is connected to the gas phase side of the membrane-type degassing device while an inert gas source is connected also on the gas phase side of the gas dissolving membrane device, and a discharge line communicates with the gas dissolving membrane device.