Dynamic DI Water Mixing for Wafer Electrostatic Charge Control
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Solution Overview
Problem
Traditional semiconductor fabrication systems using deionized (DI) water with fixed electrical resistivity fail to effectively manage electrostatic charges, leading to particle contamination and defects on wafers during immersion lithography processes, as they cannot adapt to varying resistivity requirements across different stages of the process.
Innovation Solution
A system and method for providing DI water with dynamic electrical resistivity, utilizing multiple DI water sources with different resistivities and flow control devices, such as dampers or valves, controlled by a feedback loop to adjust the resistivity in real-time, ensuring the target resistivity is maintained during the semiconductor fabrication process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If deionized water with fixed electrical resistivity is used, then the system is simple and easy to operate, but it cannot effectively manage electrostatic charges leading to particle contamination and defects
Solution Approach 1:
The patent divides the water supply system into multiple independent sources, each providing DI water with different electrical resistivities. This segmentation allows the system to select and combine water sources based on specific process requirements, thereby improving electrostatic charge management while maintaining operational simplicity through modular architecture.
Solution Approach 2:
The patent implements dynamic adjustment of electrical resistivity by enabling real-time switching between multiple DI water sources with different resistivities. This dynamic capability allows the system to adapt to varying electrostatic charge management requirements during different fabrication stages, resolving the contradiction between reliability and complexity.
2Object-affected harmful factors
If multiple DI water sources with different resistivities are mixed, then electrostatic charge accumulation is reduced, but the system complexity and control difficulty increase
Solution Approach 1:
The patent incorporates feedback control mechanisms that monitor electrostatic charge levels and automatically adjust the mixing ratio of DI water from different sources. This feedback system simplifies operation by eliminating manual intervention, allowing the system to automatically optimize charge management while maintaining ease of operation through automated control.
Solution Approach 2:
The patent introduces flow control valves and mixing chambers as intermediary components that automate the complex task of mixing DI water from multiple sources. These intermediaries handle the complexity of ratio control and mixing, thereby reducing electrostatic charge accumulation while preserving ease of operation through automated intermediary devices.
3Manufacturing precision
If dynamic resistivity adjustment is implemented, then particle contamination and defects are reduced, but the device complexity increases
Solution Approach 1:
The patent segments the water supply into multiple sources with different resistivities, each optimized for specific fabrication stages. This segmentation enables precise control over electrostatic charge management, thereby reducing particle contamination and defects while maintaining manageable system complexity through modular, independent source units.
Solution Approach 2:
The patent changes the electrical resistivity parameter of DI water dynamically by selecting from multiple sources with different resistivity values. This parameter change capability allows optimization of wafer defect reduction for different process stages while managing device complexity through standardized, interchangeable water source modules.
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 approach effectively reduces electrostatic charge accumulation on wafers by dynamically adjusting the electrical resistivity of DI water, enhancing the semiconductor fabrication process with reduced costs, simplified operations, and improved performance.
Implementation Method 1
An electrical resistivity of the first DI water is different from an electrical resistivity of the second DI water
Data Source
AI summary
A method includes mixing a first deionized water (DI) water from a first pipe and a second DI water from a second pipe in a merging pipe that is in fluid communication with the first pipe and the second pipe. An electrical resistivity of the first DI water is different from an electrical resistivity of the second DI water. A mixture of the first DI water and the second DI water is applied from the merging pipe onto a wafer.