Microlithographic Mirror Array Heat Dissipation via Segmented Articulations
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Solution Overview
Problem
Microlithographic projection exposure apparatuses face challenges in effectively dissipating heat from mirror arrays, leading to potential overheating due to light absorption, especially in EUV systems where absorption losses are significant, and conventional heat dissipation methods are inadequate.
Innovation Solution
The apparatus employs a microlithographic projection exposure system with a mirror array that utilizes subdivided solid-state articulations and additional thermal conduction elements, fluidic cooling, and sliding bearings to enhance heat dissipation, including the use of flexible sealing means and high-pressure gases to improve thermal conductivity and convection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the reflective layer system is directly attached to the mirror body, then the structure is simple, but heat dissipation is insufficient leading to overheating
Solution Approach 1:
The articulation part is subdivided into multiple articulation elements spaced apart in the plane of bending. This segmentation increases the surface area for heat dissipation while maintaining the structural functionality of the articulation system.
Solution Approach 2:
A liquid or gas is introduced as an intermediary substance between the reflective layer system and the mirror body to improve thermal conductivity. This intermediary facilitates more efficient heat transfer from the reflective layer to the mirror body without requiring direct attachment.
2Temperature
If the articulation part is made rigid for structural stability, then mechanical strength is improved, but heat dissipation is reduced
Solution Approach 1:
By subdividing the articulation part into multiple elements spaced apart, the patent achieves both goals: the segmented structure provides adequate mechanical strength while increasing the surface area for heat dissipation. The spacing between elements allows heat to escape more effectively.
Solution Approach 2:
Different regions of the articulation system are given different properties - the articulation elements maintain structural integrity while the spaced-apart configuration in the bending plane optimizes heat dissipation pathways without compromising overall strength.
3Temperature
If conventional bonding methods are used to attach the reflective surface, then manufacturing is simplified, but heat dissipation remains inadequate
Solution Approach 1:
The introduction of liquid or gas as an intermediary substance between the reflective surface and the substrate provides improved thermal conductivity. While this adds a step to the manufacturing process, it significantly enhances heat dissipation performance.
Solution Approach 2:
The patent changes the thermal conductivity parameter of the interface between the reflective surface and the substrate by introducing a liquid or gas medium. This parameter change enables more effective heat transfer without fundamentally altering the bonding method.
4Temperature
If the mirror array is used in EUV environment with low pressure, then the optical performance is improved, but heat dissipation is worsened due to reduced convection
Solution Approach 1:
The segmented articulation structure with spaced elements creates multiple heat dissipation pathways that are effective even in low-pressure EUV environments where convection is reduced. The increased surface area compensates for the reduced convective heat transfer.
Solution Approach 2:
By introducing liquid or gas intermediaries with high thermal conductivity between the reflective surfaces and substrates, the patent ensures efficient heat conduction that works effectively in the low-pressure EUV environment where conventional convection-based cooling is less effective.
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 overheating by increasing heat flux without compromising the flexural properties of the articulation system, allowing for reliable operation even in low-pressure EUV environments.
Implementation Method 1
The articulation part is subdivided into a plurality of articulation elements that are spaced apart from each other in the plane of bending in order to reduce the flexural stiffness of the articulation part
Implementation Method 2
Adjacent articulation elements may slightly touch one another or, if spaced apart from one another, a liquid or a gas may be situated between the articulation elements
Implementation Method 3
The use of flexible sealing means and high-pressure gases to improve thermal conductivity and convection
Data Source
Figure 1~2
Figure 3~4
Figure 5~7
AI summary
A microlithographic projection exposure apparatus has a mirror array having a base body and a plurality of mirror units, each of which comprises a mirror and a solid-state articulation, which has at least one articulation part that connects the mirror to the base body. A control device makes it possible to modify the alignment of the respective mirror relative to the base body. Mutually opposing surfaces of the mirror and of the base body, or of a mirror support body connected to it, are designed as corresponding glide surfaces of a sliding bearing.