EUV Collector Mirror Alignment via Pre-Registered Image Data
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Solution Overview
Problem
The EUV light source apparatus experiences uneven angular distribution of EUV light due to misalignment between plasma and the collector mirror over time, leading to asymmetrical illuminance, which requires manual adjustment of the collector mirror, taking several hours and depending on operator skill.
Innovation Solution
Registering multiple sets of image data representing uneven angular distribution properties and their corresponding movement directions and amounts for the collector mirror, allowing for automated alignment to achieve uniform distribution by comparing current data with stored data and applying the necessary corrections.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If manual adjustment of the collector mirror is performed to correct misalignment, then the angular distribution uniformity is improved, but the adjustment time increases significantly and depends on operator skill
Solution Approach 1:
The patent pre-registers multiple sets of mirror position data corresponding to different angular distribution states before actual operation. When adjustment is needed, the system simply retrieves and applies the pre-calculated correction data, eliminating the need for time-consuming manual real-time adjustment while maintaining high precision
Solution Approach 2:
The patent creates a database of copied mirror position configurations that correspond to different angular distribution patterns. Instead of performing complex manual adjustments, the system selects and applies a pre-copied configuration that matches the current situation, significantly reducing adjustment time while maintaining accuracy
2Manufacturing precision
If manual adjustment of the collector mirror is performed to correct misalignment, then the angular distribution uniformity is improved, but the ease of operation deteriorates due to skill dependency
Solution Approach 1:
The patent implements a system where the apparatus automatically performs the adjustment function by retrieving pre-registered mirror position data and applying corrections autonomously. The measurement unit detects the current state, the control unit selects appropriate correction data, and the mirror positioning unit executes the adjustment, making the system self-sufficient and eliminating operator skill dependency
Solution Approach 2:
The patent replaces the manual mechanical adjustment process with an automated control system that uses pre-registered data. Instead of relying on operator skill to physically adjust the mirror, the system uses automated control based on stored configuration data, substituting human operation with an automated mechanism
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 method enables rapid, skill-independent adjustment of the collector mirror to achieve uniform angular distribution, reducing adjustment time to 20-30 seconds and ensuring consistent EUV light exposure.
Implementation Method 1
electric discharge occurs between an edge part of the electric discharge electrode 2a and an edge part of the electric discharge electrode 2b, so that a plasma P is formed due to the high temperature plasma material M, whereby it is heated and excited by large current, which flows at time of electric discharge, and EUV light is emitted from this high temperature plasma P
Implementation Method 2
EUV light is emitted from this high temperature plasma P
Implementation Method 3
The emitted EUV light enters the EUV light focusing part 1b through a foil trap 5, is focused at a middle focal point f of a collector mirror 6 by the collector mirror 6
Data Source
AI summary
In an extreme ultraviolet (“EUV”) light source apparatus, uneven angle distribution images of EUV light are detected prior to an adjustment function by a detector, and angle distribution image data is recorded. Movement data corresponding to the recorded angle distribution image data is also recorded. The movement data corresponds to a movement amount and direction that the optical focusing means is moved from a position in which the angle distribution is even to the position in which the corresponding uneven angle distribution image is obtained. For the adjustment, a current angle distribution property image is detected by the detector and is compared with the uneven angle distribution property image data stored, and image data which is most closely matched with the current angle distribution property is selected. The movement data that corresponds to the selected image data is read out, and the light focusing optical means is moved based thereon.