Projection Optics Mirror Mount With Pivotable Stress Relief
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Solution Overview
Problem
Existing optical mounts for mirrors in DUV lithography apparatuses apply tensioning forces that lead to unwanted stresses in the mirrors, affecting their optical properties and limiting the ability to swap these components without causing damage.
Innovation Solution
An optical system with a mount that cohesively connects to the mirror using securing portions and pivotable joint portions, allowing for mechanical decoupling and reduced tensioning forces, enabling easy swapping and improved optical performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the mount is fixedly installed and rigidly connected to the mirror, then the mirror is securely held in position, but tensioning forces are applied to the mirror causing unwanted stresses and changes in optical properties
Solution Approach 1:
The securing portions are made pivotably connected to the outer ring via joint portions, transforming the rigid static connection into a dynamic articulated connection. This allows the mount to adapt to thermal expansion and manufacturing tolerances while securing the mirror, eliminating tensioning forces that would otherwise cause stress and optical property changes.
Solution Approach 2:
The patent changes the mechanical parameters of the connection by introducing pivotable joint portions with specific degrees of freedom. This allows the connection to accommodate dimensional changes and misalignments without generating harmful tensioning forces, while maintaining secure mounting through the cohesive connection of securing portions to the mirror.
2Stability of the object's composition
If the mount is rigidly fixed to hold the mirror securely, then positioning stability is achieved, but the ability to swap the mirror mount is limited and damage may occur
Solution Approach 1:
The mount is segmented into an outer ring and separate securing portions that are pivotably connected. This segmentation allows the securing portions to be independently positioned and locked, providing stable mounting during operation while enabling controlled release and swapping when needed, without damaging the mirror or mount.
3Strength
If conventional rigid mounting is used, then the mirror is firmly secured, but unwanted material stresses occur affecting optical properties
Solution Approach 1:
The pivotable joint portions act as intermediaries between the outer ring and the securing portions. These joints mediate the connection by allowing controlled movement and accommodation of dimensional changes, thereby securing the mirror firmly while preventing the transmission of stress that would affect optical precision.
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 solution reduces material stresses in the optical elements, facilitates easy swapping, and enhances the performance and accuracy of the projection optical unit by minimizing deformations during swapping.
Implementation Method 1
the securing portions are pivotably connected to the outer ring with the aid of joint portions
Data Source
AI summary
An optical system for a projection exposure apparatus comprises an optical element and a mount, which carries the optical element. The mount comprises an outer ring, in which the optical element is accommodated at least in portions. The outer ring comprises securing portions which are cohesively connected to the optical element. The securing portions are pivotably connected to the outer ring with the aid of joint portions. The mount comprises a tool interface for releasably securing a tool for swapping the optical system from an illumination optical unit.