Sample Deformation Mapping for Accurate Non-Contact Metrology
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Metrology systems are highly sensitive to localized deformations in samples due to factors like tensile stress and chuck imprinting, leading to inaccurate and unreliable measurements.
Innovation Solution
A map of localized deformations is generated and used to correct alterations in the angle of incidence and azimuth angle during measurement by adjusting the relative orientation of the sample to the metrology device or parameterizing these angles based on the deformation map.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If non-contact metrology systems are used to measure samples, then measurement accuracy is improved, but localized deformations of the sample cause alterations in angle of incidence and azimuth angle leading to unreliable measurements
Solution Approach 1:
The system performs preliminary measurements to generate a deformation map of the sample surface before conducting the actual metrology measurement. This advance characterization of localized deformations allows the system to compensate for angle alterations during the main measurement process, thereby maintaining both accuracy and reliability
Solution Approach 2:
The system uses the deformation map as feedback information to dynamically adjust measurement parameters such as angle of incidence and azimuth angle. By continuously referencing the pre-acquired deformation data, the system compensates for localized surface variations in real-time, ensuring reliable measurements despite sample deformations
2Stability of the object's composition
If samples are clamped to a flat chuck during measurement, then sample stability is improved, but localized deformations occur particularly in overhanging portions
Solution Approach 1:
The system acquires a deformation map of the sample while it is clamped to the chuck, capturing the exact shape alterations that occur during the measurement process. This preliminary characterization allows subsequent measurements to compensate for these predictable deformations, maintaining both stability and shape accuracy
Solution Approach 2:
The system applies different measurement strategies to different regions of the sample based on the deformation map. Areas with significant localized deformations (such as overhanging portions) receive corrected measurement parameters, while stable regions use standard measurement approaches, optimizing both stability and shape fidelity
3Ease of operation
If surface features from the chuck are imprinted on the sample surface, then sample positioning is improved, but measurement accuracy deteriorates due to localized deformations
Solution Approach 1:
The system extracts and separates the chuck imprinting effect from the actual sample features by comparing measurements taken at different positions and orientations. The deformation map isolates the chuck-induced deformations, allowing the system to subtract this artifact from the final measurement results, thereby recovering true sample characteristics
Solution Approach 2:
The deformation map serves as an intermediary data structure that mediates between the chuck-imprinted sample and the measurement analysis. By introducing this intermediate representation of localized deformations, the system can mathematically compensate for chuck-induced artifacts while preserving genuine sample features
Data Source
AI summary
Non-contact measurement of a sample is performed by compensating for local deformation of the sample. A map of localized deformations of the sample is obtained. The localized deformations, for example, may be produced by sample deformation, such as bow and warp, chuck imprinting on the sample, or both. A location on the sample is measured while the sample is mounted to the chuck. A localized deformation at the location on the sample produces an alteration of an angle of incidence, an azimuth angle, or both, for the radiation used for measuring the location. The alteration of the angle of incidence, the azimuth angle, or both, at the location is corrected based on the map of localized deformations.