Mirror Assembly Coating with Adjustable Tilt for Thickness Control
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Solution Overview
Problem
Existing mirror production methods in microlithography face challenges with coating thickness errors and adjustment errors, particularly in EUV mirrors with multilayer systems, leading to systematic impairments in optical system performance due to layer thickness deviations.
Innovation Solution
A method involving the individual tilting of mirror substrates during the coating process to set a flexible thickness profile and adjust layer properties, allowing for dynamic control of vapor deposition angles and layer characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If conventional magnetron coating apparatuses are used to deposit multilayer systems on mirror substrates, then coating process is simplified, but coating thickness errors and adjustment errors occur leading to systematic impairments in optical system performance
Solution Approach 1:
The patent introduces a tilting mechanism that allows the mirror substrate to be dynamically adjusted to different tilt angles during the coating process. This dynamic adjustment enables real-time control of the vapor deposition angle, allowing the system to compensate for coating thickness errors and achieve precise layer thickness control without requiring complex pre-calibration of the coating apparatus.
Solution Approach 2:
The patent changes the physical parameter of substrate orientation by introducing a tilting mechanism that varies the tilt angle during coating. This parameter change transforms the coating process from a static, error-prone operation to a dynamic, controllable process where the tilt angle can be adjusted to optimize deposition uniformity and correct thickness deviations.
2Manufacturing precision
If individual mirror substrates are tilted with individually settable tilt angles during coating, then layer thickness precision and optical system performance are improved, but device complexity increases
Solution Approach 1:
The patent segments the control of each mirror substrate by providing individually settable tilt angles for multiple substrates. This segmentation allows independent optimization of the coating process for each substrate, enabling precise control of layer thickness and properties without requiring complex inter-substrate coordination mechanisms.
Solution Approach 2:
The tilting mechanism enables each mirror substrate to be independently positioned and adjusted during the coating process, allowing the system to self-correct for coating errors through automated tilt angle adjustment. This self-service capability reduces the need for external intervention and complex post-coating adjustment mechanisms.
3Adaptability or versatility
If tilt angles are individually set for each mirror substrate during coating, then flexibility in setting thickness profiles is improved, but ease of operation decreases
Solution Approach 1:
The patent incorporates feedback mechanisms that monitor the coating process and automatically adjust the tilt angles of mirror substrates to achieve desired thickness profiles. This feedback control simplifies operation by eliminating the need for manual calculation and precise manual adjustment of tilt angles, while maintaining high flexibility in thickness profile configuration.
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 corrects coating errors and improves optical system performance by enabling precise control over layer thickness and other properties, such as roughness and crystallinity, enhancing the flexibility and accuracy of mirror arrangements.
Implementation Method 1
coating material from at least one target is supplied to a plurality of mirror substrates for the purpose of depositing a respective layer system on each of the mirror substrates
Data Source
AI summary
A method for producing a mirror assembly, as well as a coating system. The mirror assembly is, for instance, a mirror assembly for microlithography, e.g. for a microlithographic projection exposure system. In the method, a coating process of a plurality of mirror substrates (106, 206, 306, 406) is carried out in a coating system, wherein coating material is supplied by at least one target (103, 203, 303, 403, 503) for the deposition of at least one respective layer system on each of the mirror substrates (106, 206, 306, 406). The mirror substrates (106, 206, 306, 406) are each tilted by a tilt angle individually adjustable for each mirror substrate. This enables the respective thickness profile generated in the coating process to be adjusted individually.