EUV Mirror Block Alignment Using External Tool
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Solution Overview
Problem
In extreme ultraviolet lithography systems, the limited space within mirror assemblies makes it challenging to accommodate press-fit pins and slots for aligning multiple mirror blocks, especially when liquid metal wells and posts are present, leading to insufficient alignment precision.
Innovation Solution
An external alignment tool is used in conjunction with alignment features on the base plate to index and align mirror blocks, applying forces along the x, y, and z axes to ensure coplanarity with the base plate surfaces, allowing for precise positioning and attachment of mirror blocks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If press-fit pins, holes, and slots are used to align mirror blocks, then alignment precision is improved, but device complexity and space requirements increase
Solution Approach 1:
The patent removes the traditional press-fit pins, holes, and slots from the mirror block structure. Instead, it uses a simplified alignment mechanism where mirror blocks are positioned on a base plate with alignment features that do not require penetrating or complex fitting components, thereby reducing device complexity while maintaining alignment precision.
Solution Approach 2:
Instead of having alignment features (pins, holes, slots) embedded within the mirror blocks themselves, the patent inverts the approach by providing alignment features on the base plate that the mirror blocks interface with. This reversal eliminates the need for complex internal alignment structures in the mirror blocks.
2Manufacturing precision
If press-fit pins, holes, and slots are used for alignment, then alignment precision is improved, but the available space in the mirror assembly is insufficient
Solution Approach 1:
The patent extracts the alignment function from the mirror blocks themselves and relocates it to the base plate. This removes the volume requirements for pins, holes, and slots from the mirror block design, freeing up space within the compact mirror assembly while still achieving precise alignment.
3Temperature
If liquid metal wells and posts are added for heat transfer, then heat dissipation is improved, but available space for alignment features is reduced
Solution Approach 1:
The patent merges the alignment function with the base plate structure that already supports the liquid metal wells and posts. By providing alignment features on the base plate rather than requiring separate alignment mechanisms, the design integrates multiple functions (heat transfer and alignment) into the existing structural elements, avoiding additional space requirements.
Data Source
AI summary
Methods and apparatus for aligning a mirror block with a base plate to form a mirror assembly are disclosed. According to one aspect of the present invention, a method for forming a mirror assembly includes positioning a mirror block in contact with a base plate that has at least one alignment feature, and indexing a portion of an alignment tool with respect to the base plate. The method also includes applying at least a first force by moving the mirror block with respect to alignment feature. A determination is made as to when a first surface of the mirror block is substantially coplanar with a first surface of the alignment feature. The mirror block is coupled to the base plate when the first surface of the mirror block is substantially coplanar with the first surface of the alignment feature.