Projection Exposure Vibration Decoupling With Negative Stiffness
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Solution Overview
Problem
The design of projection exposure apparatuses, particularly EUV lithography systems, faces challenges in decoupling mechanical excitations due to the use of larger optical units with high numerical apertures, which are sensitive to mechanical vibrations, leading to stress and vibration transmission issues.
Innovation Solution
A decoupling device is implemented with a combination of positive and negative stiffness elements to decouple components in multiple degrees of freedom, using spring and magnetic elements to counteract vibrations and allow for low decoupling frequencies even with larger masses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If larger optical units with high numerical aperture are used, then imaging performance is improved, but sensitivity to mechanical vibrations increases
Solution Approach 1:
The system is divided into two separate components: a force frame that generates mechanical excitations and a sensor frame that detects signals. By spatially separating these functions into independent frames, the patent reduces the transmission of mechanical vibrations from the force frame to the sensor frame, thereby maintaining high imaging performance while reducing vibration sensitivity.
Solution Approach 2:
A decoupling device is introduced as an intermediary element between the force frame and sensor frame. This decoupling device mechanically isolates the sensor frame from vibrations generated by the force frame, allowing the sensor frame to remain stable and precise while the force frame can operate with high numerical aperture optical units.
2Object-affected harmful factors
If soft vibration isolators are used to reduce vibration transmission, then vibration isolation is improved, but mechanical stiffness decreases
Solution Approach 1:
The decoupling device provides different mechanical properties at different locations and directions. It offers soft isolation in vertical directions to reduce vibration transmission, while maintaining horizontal stability through the structural design. This localized differentiation of mechanical properties allows simultaneous achievement of vibration isolation and structural stability.
Solution Approach 2:
The decoupling device incorporates dynamic characteristics that allow it to adapt to different vibration frequencies and amplitudes. The system can dynamically respond to mechanical excitations by providing appropriate isolation stiffness, thereby reducing vibration transmission while maintaining necessary mechanical support.
3Manufacturing precision
If larger masses are used in optical units, then optical performance is improved, but decoupling frequency increases
Solution Approach 1:
The decoupling device incorporates counterbalancing elements that offset the inertial effects of large optical masses. By using counterweights or balancing mechanisms within the decoupling device, the system reduces the effective mass that contributes to vibration, thereby lowering the decoupling frequency while maintaining the large mass necessary for high optical performance.
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 effectively decouples mechanical excitations across multiple degrees of freedom, reducing stress and vibration transmission, thereby enhancing the stability and precision of projection exposure apparatuses.
Implementation Method 1
first decoupling elements, which have a positive stiffness
Implementation Method 2
second decoupling elements, which have a negative stiffness
Implementation Method 3
the decoupling device is designed to decouple the second component from mechanical excitations of the first component
Implementation Method 4
A decoupling device is implemented with a combination of positive and negative stiffness elements to decouple components in multiple degrees of freedom, using spring and magnetic elements
Implementation Method 5
A decoupling device is implemented with a combination of positive and negative stiffness elements to decouple components in multiple degrees of freedom, using spring and magnetic elements
Data Source
AI summary
A system for a projection exposure apparatus which comprises a first component, a second component, and a decoupling device configured to decouple the second component in more than one degree of freedom from mechanical excitations of the first component. The decoupling device comprises first decoupling elements which have a positive stiffness. The decoupling device also comprises second decoupling elements, which have a negative stiffness. The decoupling device further comprises a third component, which is arranged between the first and second components.