EUV Exposure System Mask Electrostatic Particle Removal
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Solution Overview
Problem
Existing extreme ultraviolet exposure systems face challenges in effectively removing charged particles due to their low vacuum state, which limits particle removal through airflow, especially for particles electrostatically adsorbed to surfaces.
Innovation Solution
An extreme ultraviolet exposure system incorporating an upper electrostatic chuck with alternating first and second electrodes generating different polarities, and a mask with a metal thin film pattern that selectively shields or transmits the electric field to attract and repel charged particles, allowing for their effective removal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If airflow is used to remove particles in the exposure chamber, then particle removal is achieved, but charged particles electrostatically adsorbed to surfaces cannot be effectively removed due to the low vacuum state
Solution Approach 1:
The patent replaces the mechanical airflow-based particle removal system with an electrostatic field-based system. Electrostatic chucks with patterned electrodes generate electrostatic fields that attract and hold charged particles on their surfaces, enabling removal of particles that airflow cannot eliminate due to electrostatic adsorption to surfaces.
Solution Approach 2:
The patent changes the physical state and properties of the particle removal mechanism by introducing electrostatic fields. By controlling the voltage applied to the electrostatic chuck electrodes, the system can dynamically adjust the electrostatic field strength to attract and hold charged particles, fundamentally changing how particles are captured compared to traditional airflow methods.
2Productivity
If a metal thin film pattern is applied to the mask to shield electric fields, then electrostatic particle attraction is achieved in specific regions, but the mask structure becomes more complex
Solution Approach 1:
The patent applies local quality by creating a metal thin film pattern on the mask rather than uniform coverage. The pattern includes metal thin films in first regions to shield electric fields and prevent particle attraction, while leaving second regions without metal thin films to allow electric field transmission for particle attraction. This localized differentiation enables selective particle removal while maintaining overall mask functionality.
Solution Approach 2:
The mask is segmented into distinct functional regions: first regions with metal thin films for electric field shielding and second regions without metal thin films for electric field transmission. This segmentation allows different parts of the mask to perform different functions - protecting certain areas from particle attraction while enabling particle attraction in other areas.
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 enables the efficient attraction and removal of charged particles from the exposure chamber, overcoming the limitations of airflow in low vacuum environments by utilizing electrostatic forces, thereby improving the cleanliness and operational efficiency of the system.
Implementation Method 1
the first and second electrodes generating an electric field of different polarities, respectively, to provide an electrostatic force
Implementation Method 2
the first and second electrodes generating an electric field of different polarities, respectively
Implementation Method 3
a metal thin film pattern including a first region in which a metal thin film that shields the electric field is disposed, and a second region in which the metal thin film is not disposed and through which the electric field is transmitted
Implementation Method 4
a mask that is attachable to the lower surface of the upper electrostatic chuck by the electrostatic force
Data Source
AI summary
An extreme ultraviolet exposure system includes an exposure chamber having an internal space, upper and lower electrostatic chucks, a power supply, a light source, and a mask. The upper electrostatic chuck includes first and second electrodes that are adjacent to one another and that generate an electric field of different polarities, respectively, to provide an electrostatic force. The mask is attachable to the lower surface of the upper electrostatic chuck by the electrostatic force. The mask has a metal thin film pattern including a first region in which a metal thin film that shields the electric field, and a second region in which the metal thin film is not disposed and through which the electric field is transmitted. When the mask is attached, the electric field transmitted through the second region applies an attractive force or a repulsive force to charged particles in the exposure chamber.