Transmissive Correction Plate for Lithography Telecentricity Control
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Solution Overview
Problem
Existing lithographic apparatuses face challenges in controlling the angular distribution of radiation beams, leading to non-telecentricity issues that cause asymmetric angles of incidence, pattern shifts, and overlay problems, which are difficult to correct with fixed correction profiles like wedges or reticles.
Innovation Solution
Implementing a transmissive correction plate with a varying parameter profile, such as a varying thickness or refractive index, to make local angular redistributions of radiation, counteracting non-telecentricity by aligning sections of the plate to match the telecentricity fingerprint of the apparatus.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If fixed correction profiles (wedges or reticles) are used to correct non-telecentricity, then correction can be applied, but the correction is ineffective for varying telecentricity profiles and causes pattern shifts and overlay problems
Solution Approach 1:
The correction plate is made movable relative to the radiation beam, allowing dynamic adjustment of the correction profile. This enables the system to adapt to different telecentricity profiles by changing the position of the correction plate, thereby resolving the contradiction between providing fixed correction and needing adaptability to varying conditions
Solution Approach 2:
The invention changes the parameter of the correction plate's position relative to the beam to achieve different correction effects. By varying the position parameter, the system can match different telecentricity fingerprints, thus improving both correction accuracy and adaptability
2Manufacturing precision
If multiple correction elements are used to address different non-telecentricity issues, then comprehensive correction can be achieved, but device complexity increases
Solution Approach 1:
A single correction plate is designed to perform multiple correction functions by moving to different positions. This universal element can address various telecentricity profile types (first order, second order, etc.), replacing the need for multiple specialized correction elements and thereby reducing device complexity while maintaining comprehensive correction performance
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 solution effectively corrects non-telecentricity, maintaining radiation intensity uniformity while adapting to different telecentricity profiles, reducing the need for multiple correction elements and minimizing performance degradation.
Implementation Method 1
at least one transmissive correction plate comprising a varying parameter profile configured to make a local angular redistribution of radiation transmitted through said at least one transmissive correction plate
Data Source
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AI summary
There is provided an illumination uniformity correction apparatus for use in an illumination system comprising: at least one transmissive correction plate comprising a varying parameter profile configured to make a local angular redistribution of radiation transmitted through said at least one transmissive correction plate.