Deflection Device With Refractive Power In Microlithography

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Solution Overview

Problem

Microlithographic projection exposure systems face challenges in achieving flexible variation of intensity distribution with limited maximum tilt angles of mirror elements, leading to mechanically complex and costly Fourier optics with large focal lengths.

Innovation Solution

Incorporating a deflection device with refractive power surfaces downstream of the mirror arrangement to convert angular illumination light into spatial distributions in the pupil plane, reducing the need for extensive refractive lenses and allowing for a more compact optical design.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the maximum tilt angle of mirror elements is limited to a few degrees to avoid mechanical problems and heat dissipation issues, then the Fourier optics must have relatively large focal lengths (several meters), which increases device complexity and cost

Engineering Contradiction:
Improvemechanical stability of mirror elementsVSAvoidcomplexity of Fourier optics
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The deflection device is merged with the Fourier optics by providing at least one deflection surface with refractive power. This integration allows the deflection device to perform both beam deflection and Fourier transformation functions, eliminating the need for separate large-focal-length optics and reducing overall system complexity while maintaining reliable mirror element operation at limited tilt angles

Inventive Principle:
Principle #5Merging (Combining)

2Length of stationary object

If Fourier optics are designed as an optical zoom system with multiple refractive lenses to achieve large focal lengths, then the material and cost expenditure fundamentally increases

Engineering Contradiction:
Improvefocal length of Fourier opticsVSAvoidmaterial and cost expenditure
Core Design Contradiction:
Length of stationary objectVSEase of manufacture

Solution Approach 1:

The deflection device is merged with the Fourier optics by providing at least one deflection surface with refractive power. This integration allows the deflection device to perform both beam deflection and Fourier transformation functions, eliminating the need for separate large-focal-length optics and reducing overall system complexity while maintaining reliable mirror element operation at limited tilt angles

Inventive Principle:
Principle #5Merging (Combining)

3Length of stationary object

If multiple refractive lenses are used in the Fourier optics to achieve large focal lengths, then the structural complexity and spatial accommodation requirements increase

Engineering Contradiction:
Improvefocal length of Fourier opticsVSAvoidstructural complexity of optical design
Core Design Contradiction:
Length of stationary objectVSDevice complexity

Solution Approach 1:

The deflection device is merged with the Fourier optics by providing at least one deflection surface with refractive power. This integration allows the deflection device to perform both beam deflection and Fourier transformation functions, eliminating the need for separate large-focal-length optics and reducing overall system complexity while maintaining reliable mirror element operation at limited tilt angles

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 enables flexible illumination settings with reduced mechanical stress and heat dissipation issues, while minimizing the number of refractive lenses required, resulting in a more compact and cost-effective optical system.

Implementation Method 1

a deflection device which, in relation to the optical beam path, has at least one deflection surface for deflecting the optical axis downstream of the mirror arrangement with refractive power

Methodology Applied
Scientific EffectRefraction: Refraction

Data Source

PatentEP2829917B1Microlithographic projection exposure apparatus
Publication Date: 2020.01.15 CARL ZEISS SMT GMBH
  • EP2829917B1 patent drawingFigure 1
  • EP2829917B1 patent drawingFigure 2
  • EP2829917B1 patent drawingFigure 3

AI summary

The invention relates to an optical system for a microlithographic projection exposure system. An optical system for a microlithographic projection exposure system comprises an optical axis (OA), at least one mirror arrangement (200, 300) which has a plurality of mirror elements (200a, 200b, 200c,..., 300a, 300b, 300c,...) wherein these mirror elements are independently adjustable to change the angular distribution of the light reflected by the mirror arrangement, and a deflection device (210, 310) wherein this deflection device (210, 310) has at least one deflection surface (212) with respect to the optical beam path after the mirror arrangement (200, 300), at which a deflection of the optical axis (OA) occurs, and wherein this at least one deflection surface (212) has refractive power.