Selective Mark Illumination in Lithography Detection
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Solution Overview
Problem
Existing imprint apparatuses face challenges in accurately detecting the relative positions of substrate-side marks and mold-side marks due to the need for selective illumination of each mark to enhance illuminance, rather than illuminating the whole shot region, which is not efficiently addressed by current alignment methods.
Innovation Solution
A detection apparatus with an optical system and illumination unit that selectively illuminates each mark using multiple light beams, allowing for individual adjustment of the incident angle on the pupil plane to change the irradiated position on the substrate, thereby improving illuminance and accuracy of mark detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If the whole shot region is illuminated to detect multiple marks, then the detection coverage is improved, but the illuminance at each mark position becomes insufficient
Solution Approach 1:
The illumination is segmented into multiple independent light beams, each directed at a specific mark position. The illumination unit generates a plurality of light beams that individually illuminate different substrate-side marks and mold-side marks, allowing each mark to receive sufficient illuminance while maintaining coverage of the entire shot region.
Solution Approach 2:
Each light beam is optimized to provide localized illumination at its target mark position. By adjusting the incident angle of each light beam on the pupil plane, the system achieves high illuminance at specific locations without requiring uniform illumination across the entire shot region, thus resolving the contradiction between coverage and illuminance intensity.
2Measurement precision
If selective illumination of each mark is implemented to improve illuminance, then the detection accuracy is improved, but the device complexity increases
Solution Approach 1:
A beam splitting element is introduced as an intermediary component to divide a single light source into multiple light beams. This element, combined with the pupil plane positioning mechanism, enables selective illumination of multiple marks without requiring multiple independent light sources, thus improving detection accuracy while limiting the increase in device complexity.
Solution Approach 2:
The system controls the incident angle of each light beam on the pupil plane to change the irradiated position on the substrate. By adjusting this angular parameter, the same illumination unit can dynamically direct light to different mark positions, achieving selective illumination without adding complex mechanical positioning systems for each light beam.
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 approach enables precise detection of substrate-side marks and mold-side marks, enhancing the alignment process by selectively illuminating each mark, thereby improving the overall accuracy and efficiency of the imprint process.
Implementation Method 1
an illumination unit configured to selectively illuminate the plurality of marks with a plurality of light beams via the optical system such that each of the plurality of marks is illuminated with at least one light beam
Data Source
AI summary
The present invention provides a detection apparatus for detecting a plurality of marks provided on a substrate, comprising: an optical system; an illumination unit configured to selectively illuminate the plurality of marks with a plurality of light beams via the optical system such that each of the plurality of marks is illuminated with at least one light beam; and an image capturing device configured to capture an image of the plurality of marks via the optical system, wherein the illumination unit includes a change unit configured to individually change an incident angle of each of the plurality of light beams on a pupil plane of the optical system, thereby changing an irradiated position of each of the plurality of light beams on the substrate.