Dual Detector Lithography Mask Detection Device
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Solution Overview
Problem
Current detection devices for lithography masks face limitations in dynamic range without compromising spatial resolution, particularly in detecting structures using high-intensity and low-intensity beam paths with varying light intensities.
Innovation Solution
The use of a detection device with both high-intensity (HI) and low-intensity (LI) spatially resolving detectors, where the detection light is split into separate beam paths with intensity ratios of at least 3:1, allowing for increased dynamic range without sacrificing spatial resolution, and optionally incorporating additional medium-intensity detectors for enhanced signal-to-noise ratio.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a single detector is used for detection, then the device complexity is low, but the dynamic range is limited
Solution Approach 1:
The detection system is segmented into multiple detectors (first detector for high-intensity light, second detector for low-intensity light) that each handle specific intensity ranges. This segmentation allows the system to achieve a wide dynamic range by combining the capabilities of individual detectors, resolving the contradiction between limited dynamic range and device complexity.
Solution Approach 2:
The system changes the parameter of detection sensitivity by using different detectors optimized for different light intensity ranges. The first detector is optimized for high-intensity light while the second detector is optimized for low-intensity light, allowing the system to adapt to varying signal intensities and achieve extended dynamic range without excessive complexity.
2Measurement precision
If high-intensity detection is used, then the signal-to-noise ratio is improved, but detector overload occurs
Solution Approach 1:
Different detectors are assigned to different regions of the intensity spectrum. The first detector with high full-well capacity handles high-intensity signals where detector overload would occur, while the second detector handles low-intensity signals where signal-to-noise ratio is critical. This local quality assignment resolves the contradiction by optimizing each detector for its specific intensity range.
3Object-affected harmful factors
If low-intensity detection is used, then detector overload is avoided, but the signal-to-noise ratio deteriorates
Solution Approach 1:
The second detector is specifically optimized for low-intensity signal detection with high quantum efficiency and low noise characteristics. By assigning this specialized detector to the low-intensity range, the system maintains excellent signal-to-noise ratio while avoiding detector overload, resolving the contradiction between overload avoidance and measurement precision.
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 significantly enhances the dynamic range of the detection device, enabling more accurate and sensitive detection of structures on lithography masks by effectively managing signal overload and noise levels across varying light intensities.
Implementation Method 1
the detection light being split into at least two beam paths having different detection light intensities, namely into at least one high-intensity beam path and into at least one low-intensity beam path
Data Source
AI summary
A detection device serves for detecting a structure on an area portion of a lithography mask. The detection device has a first spatially resolving detector and also a further spatially resolving detector arranged separately therefrom. The first spatially resolving detector is embodied as a high-intensity (HI) detector and is arranged in an HI beam path of the detection light which emanates from the mask area portion. The further spatially resolving detector is embodied as a low-intensity (LI) detector and is arranged in an LI beam path of the detection light. The HI beam path on the one hand and the LI beam path on the other hand are embodied such that the HI detector is illuminated with a detection light intensity that is at least twice the magnitude of the detection light intensity with which the LI detector is illuminated. The two spatially resolving detectors are embodied for simultaneously detecting the detection light. The result is a detection device whose dynamic range is increased without limitations of a spatial resolution. Alternatively or additionally, the detection device, by way of the two spatially resolving detectors, can also be embodied for the polarization-resolved measurement of the detection light.