Dual Vacuum Chamber Diffractive Element Transfer for EUV Mirror Testing
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Interferometric mirror testing in EUV microlithography faces challenges due to thermally induced deformations in diffractive optical elements under vacuum conditions, leading to lengthy temperature-control phases and reduced measurement throughput.
Innovation Solution
The use of two vacuum chambers, where one chamber maintains a constant vacuum for diffractive optical elements and the other alternates between atmospheric and vacuum conditions, allowing for rapid testing of EUV mirrors without the need for lengthy temperature-control phases.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If interferometric mirror testing is carried out under vacuum conditions to avoid atmospheric interference, then measurement precision is improved, but measurement time increases due to lengthy temperature-control phases required to avoid thermally induced deformations
Solution Approach 1:
The system is divided into two separate vacuum chambers: a first vacuum chamber for holding the diffractive optical element and a second vacuum chamber for holding the test object. This segmentation allows each chamber to be independently controlled, enabling the diffractive optical element to remain in a stable vacuum environment without requiring lengthy temperature-equilibration periods, thus reducing overall measurement time while maintaining precision.
Solution Approach 2:
A transfer mechanism acts as an intermediary to move the diffractive optical element between the first vacuum chamber and the second vacuum chamber. This allows the element to be quickly exchanged without breaking the vacuum seal, eliminating the need for lengthy temperature-control phases while maintaining measurement precision under vacuum conditions.
2Adaptability or versatility
If multiple diffractive optical elements are stored in the same vacuum chamber as the test arrangement, then adaptability is improved, but device complexity increases due to additional storage infrastructure
Solution Approach 1:
The system segments the vacuum environment into a dedicated storage chamber (first vacuum chamber) and a test chamber (second vacuum chamber). This allows multiple diffractive optical elements to be stored in a dedicated space without complicating the test arrangement itself, maintaining adaptability while managing device complexity through functional separation.
Solution Approach 2:
The first vacuum chamber serves multiple functions: it stores multiple diffractive optical elements, maintains vacuum conditions, and provides a stable environment for the elements before testing. This multi-functionality improves adaptability by allowing quick element changes while avoiding the complexity of integrating storage within the test arrangement.
3Ease of operation
If the diffractive optical element is exposed to atmospheric pressure during storage, then ease of operation is improved, but measurement precision deteriorates due to thermally induced deformations
Solution Approach 1:
The transfer mechanism serves as an intermediary that moves the diffractive optical element between atmospheric pressure (for easy handling and storage) and vacuum conditions (for precise measurement). This allows the element to be easily operated and stored at atmospheric pressure while maintaining measurement precision when tested under vacuum, eliminating the need for continuous vacuum maintenance during storage.
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 enhances measurement accuracy and throughput by avoiding thermally induced deformations in diffractive optical elements while maintaining stable conditions for EUV mirrors, thereby reducing overall testing time.
Implementation Method 1
a test arrangement for determining the surface shape of a test object (111, 112, 113, ...) using a test wave, the test wave having a wavefront produced by diffraction at a diffractive optical element (121, 122, 123, ...)
Implementation Method 2
the introduction of optical components into a vacuum chamber is accompanied by surface cooling of the respective optical components as a consequence of the expansion of air that occurs during the evacuation
Data Source
AI summary
A device and a method for characterizing the surface shape of a test object. The device for characterizing the surface shape of a test object has a test arrangement (130, 230) for determining the surface shape of a test object (111, 112, 113, 211, 212, 213) using a test wave. The test wave has a wavefront generated by diffraction at a diffractive optical element. The device additionally has a first vacuum chamber (110, 210) and a second vacuum chamber (120, 220), wherein the second vacuum chamber (120, 220) has a magazine for mounting at least two diffractive optical elements (121, 122, 123, 221, 222, 223).