Static-Pressure Temperature Conditioning for Lithography Mirrors
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Solution Overview
Problem
Existing temperature conditioning systems in lithographic apparatuses using conditioning liquid cause flow-induced vibrations and pressure fluctuations, which negatively affect the focus and overlay performance due to deformations in mirror elements.
Innovation Solution
A temperature conditioning system with a supply chamber and discharge chamber arrangement creating a static pressure difference to drive a continuous flow through the conditioning conduit, using sub-atmospheric pressures and gas volumes to dampen pressure fluctuations, decoupling the conditioning conduit from the return conduit to minimize vibrations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a pump is used to circulate conditioning liquid through the conditioning conduit, then the temperature conditioning function is achieved, but pressure fluctuations are created that cause vibrations of the object
Solution Approach 1:
The system is divided into a first liquid circuit (conditioning conduit through mirror element) and a second liquid circuit (return conduit with pump), connected via coupling chambers. This segmentation isolates the pump-induced pressure fluctuations from the conditioning conduit, preventing vibrations while maintaining temperature control functionality.
Solution Approach 2:
Coupling chambers filled with gas act as intermediaries between the pump-driven return conduit and the conditioning conduit. The gas-filled chambers absorb and dampen pressure fluctuations, serving as a buffer that prevents vibration transmission to the mirror element while allowing continuous liquid circulation.
2Temperature
If conditioning liquid is pumped through the conditioning conduit, then thermal conditioning is provided, but the pressure of the conditioning liquid influences surface figure deformations of the mirror element
Solution Approach 1:
The liquid circuit is segmented into conditioning and return paths, with the pump located only in the return conduit. This separation ensures that high-pressure pump operation does not directly affect the pressure in the conditioning conduit, thereby preventing surface figure deformations while maintaining effective thermal conditioning.
Solution Approach 2:
Gas-filled coupling chambers serve as pressure-isolating intermediaries between the pump and the conditioning conduit. These chambers decouple the pressure variations generated by the pump from the conditioning liquid, maintaining stable pressure at the mirror element surface and preventing figure deformations.
3Device complexity
If the conditioning conduit is connected directly to the return conduit, then the system is simpler, but vibrations from the pump are propagated through the conditioning liquid to the object
Solution Approach 1:
The system divides the liquid circulation path into distinct conditioning and return circuits, connected through coupling chambers. This segmentation adds structural elements but effectively isolates pressure fluctuations from the object, achieving a balance between complexity and vibration reduction.
Solution Approach 2:
Gas-filled coupling chambers are introduced as intermediary components between the conditioning and return conduits. These chambers act as vibration buffers, absorbing pressure fluctuations without significantly increasing system complexity, as they can be integrated into existing conduit connections.
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 significantly reduces flow-induced vibrations, improving the focus and overlay performance of the lithographic apparatus by stabilizing the mirror elements and reducing thermal deformations.
Implementation Method 1
wherein the temperature conditioning system is arranged to provide a static pressure difference between the supply chamber outlet and the discharge chamber inlet to create a flow through the conditioning conduit
Implementation Method 2
using sub-atmospheric pressures and gas volumes to dampen pressure fluctuations
Implementation Method 3
This heat load may cause internal thermal stresses that may lead to deformation of the mirror elements
Data Source
AI summary
A temperature conditioning system using conditioning liquid to condition a temperature of an object, the system including a conditioning conduit, a return conduit, a supply chamber, and a discharge chamber, wherein the temperature conditioning system is arranged to provide a static pressure difference between the supply chamber outlet and the discharge chamber inlet to create a flow through the conditioning conduit. A lithography apparatus and a method of temperature conditioning an object is also described.