Carbonated Deionized Water System for Semiconductor Cleaning
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Solution Overview
Problem
Current methods for generating carbonated deionized water for semiconductor wet cleaning are costly, complex, and inefficient due to the need for excess gas usage, leading to toxicity and disposal issues, with inadequate control over CO2 concentration and frequent bubble formation.
Innovation Solution
A system utilizing mass flow controllers and feedback loops to precisely control the CO2 concentration in deionized water, ensuring complete dissolution of CO2 and eliminating the need for nitrogen gas, thereby reducing system complexity and cost, while maintaining a high level of control over CO2 concentration and preventing bubble formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If excess carbon dioxide gas is used to carbonate deionized water, then complete dissolution and bubble-free water is achieved, but toxicity and disposal problems occur with unused gases
Solution Approach 1:
The system employs a feedback control mechanism where a sensor detects the conductivity of the carbonated water and sends this information to a controller, which adjusts the mass flow controller to regulate CO2 gas flow. This closed-loop feedback ensures complete dissolution of CO2 without excess gas, eliminating toxicity and disposal problems while maintaining reliable carbonation.
Solution Approach 2:
The system changes the conductivity parameter as a control variable to indicate the degree of carbonation. By monitoring conductivity changes and adjusting CO2 flow accordingly, the system achieves complete gas dissolution without excess, preventing harmful effects while ensuring reliable carbonation.
2Measurement precision
If complex instrumentation is used to control gas proportions, then precise CO2 concentration control is achieved, but system cost and complexity increase significantly
Solution Approach 1:
The patent uses a simple feedback loop consisting of a conductivity sensor and a controller that adjusts the mass flow controller. This minimal feedback instrumentation achieves precise CO2 concentration control without the need for complex gas analysis equipment, resolving the contradiction between measurement precision and device complexity.
Solution Approach 2:
The system uses conductivity as an intermediary parameter to control CO2 concentration indirectly. Instead of directly measuring CO2 concentration with complex sensors, the system monitors conductivity changes caused by carbonation and uses this intermediary signal to regulate gas flow, achieving precise control with simple instrumentation.
3Loss of time
If mass flow controllers and feedback loops are used to precisely control CO2 concentration, then response time is reduced, but system complexity increases
Solution Approach 1:
The feedback loop with conductivity sensor and controller provides real-time adjustment of CO2 flow, enabling rapid response to concentration changes. This simple feedback mechanism reduces response time without requiring complex control systems, as the conductivity-based regulation responds quickly to carbonation state changes.
Solution Approach 2:
The system replaces complex mechanical gas flow control mechanisms with electronic mass flow controllers and digital feedback loops. This substitution enables precise and rapid response time control while actually reducing overall system complexity through the use of modern electronic control components rather than mechanical systems.
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 system achieves precise control over CO2 concentration in deionized water, reducing response times and eliminating bubble formation, thus minimizing damage to semiconductor devices and reducing waste and toxicity concerns, while simplifying the system and lowering costs.
Implementation Method 1
CO2-dissolved water having carbon dioxide dissolved in deionized water by a gas-liquid mixer
Implementation Method 2
at least one mass flow controller in fluid communication with the gas source and the contactor. The at least one mass flow controller can be used to control the amount and flow rate of carbon dioxide gas entering the contactor
Implementation Method 3
at least one sensor in fluid communication with the contactor and the at least one mass flow controller. The at least one sensor can be used to detect a flow rate, a temperature and/or a conductivity of the carbonated deionized water
Data Source
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AI summary
Devices, systems, and methods employed in wet cleaning semiconductor devices are provided. In particular, systems that can deliver deionized water with the desired concentration of CO2 and methods of generating deionized water with a desired concentration of CO2 for use in wet cleaning of semiconductor devices are provided.