Optical Beam Segmentation for Dynamic Range in Semiconductor Inspection
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Solution Overview
Problem
Current methods for extending the dynamic range of optical systems in semiconductor inspection are costly and result in inaccurate or incomplete signal detection due to saturation and sensitivity issues.
Innovation Solution
Generate multiple light beams with varying intensities using an optical element to illuminate a specimen, focusing the primary and secondary beams to different spots in an imaging plane, ensuring at least one unsaturated detector output is available for accurate information determination.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple sensors/detectors are added to extend dynamic range, then the dynamic range coverage is improved, but the system cost and complexity increase significantly
Solution Approach 1:
The patent segments the single light beam into multiple beams with different intensities (primary beam and secondary beams) using optical elements. This allows one detector to capture multiple intensity levels simultaneously, achieving dynamic range extension without adding multiple detectors. The segmentation of light intensity creates a cost-effective solution that maintains reliability while reducing device complexity.
2Reliability
If imaging techniques use only the non-saturated part of the saturated optical signal, then the dynamic range is extended, but the measurement accuracy deteriorates due to loss of signal information
Solution Approach 1:
The patent creates multiple beams with predetermined different intensities before illumination using optical elements. This preliminary action ensures that at least one beam intensity will produce a non-saturated detector output, avoiding the need to discard saturated signal portions. By preparing multiple intensity levels in advance, the system maintains measurement accuracy while extending dynamic range.
3Measurement precision
If a single high intensity beam is used for illumination, then the signal strength is improved, but detector saturation occurs resulting in loss of information
Solution Approach 1:
The patent segments the single high-intensity beam into multiple beams with different intensity levels using optical elements. The primary beam maintains high intensity for strong signal, while secondary beams have reduced intensities to prevent saturation. This segmentation allows the detector to capture information from at least one beam without saturation, preventing information loss while maintaining signal strength.
Solution Approach 2:
The patent changes the intensity parameter of light beams by using optical elements to create multiple beams with different intensities from a single source. This parameter change allows the system to adapt to different signal requirements and prevent detector saturation while maintaining adequate signal strength for accurate measurement.
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
Extends the dynamic range of optical systems by providing usable detector outputs even in conditions of saturation, reducing sensitivity to signal drift and ensuring accurate specimen information detection.
Implementation Method 1
The optical element is configured for separating the light beam into a primary beam and one or more pairs of secondary beams
Implementation Method 2
Focusing optics of the system are configured for simultaneously focusing the primary beam and the secondary beams to different, spatially separated spots
Data Source
AI summary
Methods and systems for extending the dynamic range of imaging systems are provided. One system includes an optical element that separates a light beam into a primary beam and one or more pairs of secondary beams. The secondary beams in each pair are located on opposite sides of the primary beam, respectively. The primary beam has a higher intensity than all of the secondary beams. Focusing optics simultaneously focus the primary beam and the secondary beams to different, spatially separated spots, respectively, in an imaging plane of the system. The system illuminates the specimen with the different, spatially separated spots. The optical element is preferably configured so that light from the spots on the specimen illuminated with the primary beam and all of the secondary beams on at least one side of the primary beam are incident on a field of view of a detector of the system.