Optical Element Replacement Device for Lithography
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Solution Overview
Problem
Lithographic projection exposure apparatuses face challenges in accurately and efficiently replacing optical elements, particularly lenses, due to the need for high precision and minimal interference with the existing structure, especially when dealing with changes in optical performance or requirements for double exposure with different reticles.
Innovation Solution
A replacement device with a receptacle system that allows for the precise introduction and fixation of optical elements on a separate holding structure, decoupled from the fixing device's forces, enabling accurate positioning and fine adjustments in multiple degrees of freedom, and includes a drive and guide mechanism for automated replacement, along with reference surfaces and sensor systems for precise alignment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the optical element is fixed directly to the holding structure using a fixing device, then the fixing is secure and reliable, but the holding structure and adjoining components are subjected to unwanted forces and deformations
Solution Approach 1:
The system is divided into separate functional components: a holding structure for positioning the optical element, and a fixing device for securing it. The fixing device is designed to act locally on the optical element without transmitting forces to the holding structure, thus segmenting the force transmission path and eliminating harmful effects on the positioning system.
Solution Approach 2:
The patent introduces an intermediary mechanism between the fixing device and the holding structure that prevents force transmission. The fixing device clamps the optical element independently, and the holding structure remains decoupled from the clamping forces, serving only as a positioning framework without being subjected to harmful mechanical stresses.
2Reliability
If the receptacle is made large enough to accommodate the optical element securely, then the fixation is stable, but the receptacle cannot be fully retracted into the housing through the opening
Solution Approach 1:
The receptacle is designed with a nested structure that allows it to be partially inserted into the housing through the opening while maintaining secure fixation of the optical element. The receptacle can be retracted into the housing to a sufficient extent for stable operation, with the optical element held firmly in place during exposure operations.
3Reliability
If the optical element is firmly clamped to prevent movement, then positioning stability is improved, but the mount experiences deformations that affect optical performance
Solution Approach 1:
The clamping function is separated from the mounting function. The fixing device provides firm clamping to prevent movement during operation, while the mount structure remains independent and free from clamping-induced deformations. This segmentation allows the optical element to be firmly secured without compromising its alignment precision.
Data Source
AI summary
Replacement devices for at least one replaceable optical element mounted at least indirectly in a lithographic projection exposure apparatus are disclosed. Lithography objectives and illumination systems are also disclosed. Methods for positioning a replaceable optical element within a lithographic projection exposure apparatus of this type, and methods for replacing a replaceable optical element within a lithographic projection exposure apparatus via a replacement device are also disclosed.