Fly's Eye Condenser Optical Channels for Microlithography
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Solution Overview
Problem
Conventional microlithographic projection exposure apparatuses experience light loss and structural complexity due to the use of refractive optical elements in the beam path, which complicates light homogenization and stabilization, especially at wavelengths above 150 nm.
Innovation Solution
The optical system eliminates refractive-power-exhibiting elements between a light distribution-producing element and the fly's eye condenser, allowing divergent illumination and using a complex fly's eye condenser design to reduce light loss and structural complexity, with beam-deflecting elements arranged to achieve superposition of images and minimize intensity variations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If refractive optical elements are used in the beam path for light homogenization and stabilization, then the illumination quality is improved, but light loss increases and structural complexity increases
Solution Approach 1:
The patent removes refractive optical elements from the beam path between the light distribution element and the fly's eye condenser, extracting only the essential beam-deflecting elements that are needed for homogenization while eliminating the light-absorbing refractive components. This extraction principle directly reduces light loss while maintaining illumination quality.
Solution Approach 2:
The patent replaces refractive optical elements with reflective beam-deflecting elements in the fly's eye condenser. This substitution uses reflection instead of refraction, eliminating the light loss associated with refractive materials while achieving the same homogenization and stabilization functions.
2Illumination intensity
If refractive optical elements are used in the beam path for light homogenization and stabilization, then the illumination quality is improved, but device complexity increases
Solution Approach 1:
The patent extracts and removes the unnecessary refractive optical elements from the beam path, retaining only the essential beam-deflecting elements of the fly's eye condenser. This simplification reduces structural complexity while preserving the core homogenization and stabilization functions.
Solution Approach 2:
The patent substitutes complex refractive optical elements with simpler reflective beam-deflecting elements arranged in the fly's eye condenser pattern. This substitution reduces manufacturing complexity and structural complexity while maintaining the required illumination quality.
3Stability of the object's composition
If a conventional fly's eye condenser design with collimated beam path is used, then field dependencies of intensity are minimized, but light loss increases due to transmission loss
Solution Approach 1:
The patent replaces the collimated beam path design with a divergent beam path design that uses reflective beam-deflecting elements. This substitution eliminates transmission loss through refractive elements while the fly's eye condenser structure maintains intensity uniformity across the field through its geometric arrangement of beam-deflecting elements.
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 minimizes light loss and structural complexity while maintaining effective homogenization and stabilization of laser light, improving the throughput and simplicity of the microlithographic projection exposure apparatus.
Implementation Method 1
a fly's eye condenser which comprises two arrangements following one another in the light propagation direction and made of beam-deflecting optical elements for producing a multiplicity of optical channels
Implementation Method 2
The use of so-called fly's eye condensers for obtaining light mixing is conventional in the illumination device
Implementation Method 3
a further important object of the fly's eye condenser lies in stabilization in this case, meaning that the position of the illumination in a specific plane of the illumination device remains unchanged in relation to variations of location and, in particular, direction of the beams emanating from the laser light source
Data Source
AI summary
An optical system of a microlithographic projection exposure apparatus designed for an operating wavelength of at least 150 nm. In one disclosed aspect, the optical system includes an element (11, 21) producing an angular distribution for light incident during the operation of the optical system and a fly's eye condenser (200, 400, 500) which includes two arrangements (210, 220, 410, 420, 510, 520) following one another in the light propagation direction and made of beam-deflecting optical elements (211-213, 221-223, 411-413, 421-423, 511-513, 521-523), which produce a multiplicity of optical channels. No optical element with refractive power is arranged in the beam path between the element (11, 21) producing an angular distribution and the fly's eye condenser (200, 400, 500).