Movable Two-Mirror EUV Focusing for Flexible Target Positioning

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Solution Overview

Problem

Existing EUV radiation generating devices face challenges in adjusting the focus position without increasing installation space or adding additional optical elements, particularly when power losses and limited space are concerns.

Innovation Solution

A focusing device comprising a paraboloid mirror and an ellipsoid or hyperboloid mirror mounted at a fixed distance, with a movement device allowing joint displacement in multiple spatial directions, enabling the focus position to be freely positioned in space without the need for additional optical elements.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a motor-driven planar deflecting mirror is used to change focus positions, then the focus position can be adjusted within the target area, but additional optical elements and actuators are required, increasing device complexity and installation space

Engineering Contradiction:
Improvefocus position adjustment capabilityVSAvoidnumber of optical elements and actuators
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent combines the paraboloid mirror and ellipsoid/hyperboloid mirror into a single integrated focusing device with a fixed distance between them. The movement device moves both mirrors together as one unit, merging multiple components into a coordinated system that reduces the need for separate actuators and optical elements while maintaining focus adjustment capability

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The integrated focusing device with movable mirrors serves multiple functions: it maintains the fixed optical relationship between the paraboloid and ellipsoid/hyperboloid mirrors for aberration-free focusing, while simultaneously enabling focus position adjustment within the target area through the movement device, eliminating the need for separate deflecting mirrors

Inventive Principle:
Principle #6Universality (Multi-functionality)

2Adaptability or versatility

If additional deflecting mirrors and actuators are added to adjust focus position, then focus flexibility is improved, but installation space increases

Engineering Contradiction:
Improvefocus position flexibilityVSAvoidinstallation space
Core Design Contradiction:
Adaptability or versatilityVSArea of stationary object

Solution Approach 1:

By merging the paraboloid mirror and ellipsoid/hhyperboloid mirror into a single movable unit with a fixed distance between them, the patent reduces the space required for multiple separate actuators and optical elements while maintaining the ability to adjust focus positions freely within the target area

Inventive Principle:
Principle #5Merging (Combining)

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 configuration allows for flexible and aberration-free positioning of the laser beam within the target area, enabling dynamic focus adjustment without increasing the complexity or size of the system, thus optimizing EUV radiation generation.

Implementation Method 1

a paraboloid mirror for expanding the laser beam

Methodology Applied
Scientific EffectReflection: Reflection

Implementation Method 2

an ellipsoid or hyperboloid mirror for focusing the expanded laser beam at a focus position within the target area

Methodology Applied
Scientific EffectFocusing: Focusing

Data Source

PatentEP3794393B1Focusing device and EUV radiation generating device having same
Publication Date: 2023.09.27 TRUMPF LASER SYSTEMS FOR SEMICONDUCTOR MANUFACTURING GMBH
  • EP3794393B1 patent drawingFigure 1
  • EP3794393B1 patent drawingFigure 2a~2b
  • EP3794393B1 patent drawingFigure 3a~3c

AI summary

The invention relates to a focusing device (15) for focusing a laser beam (3) in a target region (5), in particular for generating EUV radiation (7), comprising: a paraboloidal mirror (16) for expanding the laser beam (3), an ellipsoidal or hyperboloidal mirror (17) for focusing the expanded laser beam (3) at a focus position (P2) within the target region (5), and a movement device (19), which is designed to move the ellipsoidal or hyperboloidal mirror (17) relative to the paraboloidal mirror (16) and/or together with the paraboloidal mirror (16) in order to change the focus position (P2) within the target region (5). The invention also relates to an EUV radiation generating device (1) that comprises a focusing device (15) of this type.