Adaptive Groove Focusing Device for Trench Measurement
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Solution Overview
Problem
Conventional focusing and leveling apparatuses in projection lithography tools are unable to accurately measure the height and tilt of objects with trenches, as the measuring light spots often fall within the trenches, leading to measurement errors or impossibility due to reflection issues.
Innovation Solution
A focusing and leveling apparatus that projects multiple non-equidistant measuring light spots onto the object's surface, ensuring at least two spots are outside the trenches, allowing for effective height and tilt measurement by identifying effective light spots based on detected distances, and adjusting the object's position if necessary to relocate spots outside the trenches.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single measuring light spot is used, then the measurement process is simple, but the measurement fails when the light spot falls within a trench
Solution Approach 1:
The single measuring light spot is segmented into multiple measuring light spots (at least three) arranged in a specific pattern. This segmentation ensures that not all spots fall into trenches simultaneously, allowing the system to find valid measurement points even when some spots are blocked by trench structures.
Solution Approach 2:
The system changes the spatial parameters of the measuring light spots by arranging them in non-equidistant patterns and adjusting their positions dynamically. This allows adaptation to different trench configurations and ensures at least two spots remain outside trenches for reliable measurement.
2Device complexity
If measuring light spots are arranged in an equidistant manner, then the arrangement is simple, but all spots may simultaneously fall within trenches leading to measurement failure
Solution Approach 1:
The measuring light spots are arranged in a non-equidistant asymmetric pattern rather than a uniform grid. This asymmetric arrangement, combined with specific distance relationships between spots, prevents simultaneous alignment with periodic trench structures, ensuring measurement capability is maintained.
3Ease of operation
If the apparatus uses conventional focusing and leveling methods, then the method is straightforward, but it cannot measure objects with trenches due to reflection issues
Solution Approach 1:
The system dynamically adjusts the positions and configurations of multiple measuring light spots based on detected trench locations. This dynamic adaptation allows the straightforward focusing and leveling method to work effectively on objects with trenches by ensuring measurement spots are positioned on valid surface areas.
4Reliability
If multiple measuring light spots are projected, then measurement reliability improves, but the device complexity increases
Solution Approach 1:
The multiple measuring light spots serve multiple functions: they provide redundant measurement points, enable trench detection through pattern analysis, and allow dynamic adaptation to various surface configurations. This multi-functionality justifies the increased complexity by providing comprehensive measurement capabilities.
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 accurate height and tilt measurements on objects with trenches by ensuring effective light spots are outside the trenches, reducing measurement errors and ensuring the apparatus can function even when some light spots are within the trenches.
Implementation Method 1
Light from the light spot travels through the relay unit and is received by the detector which thereby forms a light intensity signal carrying surface height information
Data Source
AI summary
Disclosed is an adaptive groove focusing and leveling device for measuring the height and the inclination of the surface of a measured object (400). The measured object (400) is provided with cyclic grooves (401) in the surface and supported by a moving table; the focusing and leveling device sequentially comprises an illumination unit, a projection unit, a detection unit and a detector (212); the measured object (400) is positioned between the projection unit and the detection unit along the light path, the projection unit comprises a projection slit (203) and is used for forming a plurality of measuring points (501) on the measured object (400), and each measuring point (501) comprises at least three measuring child light spots (502), wherein the at least three measuring child light spots (502) are arranged at unequal intervals, so that when the plurality of measuring points (501) are projected to the surface of the measured object (400), at least two of the at least three measuring child light spots (502) of each measuring point (501) can be positioned outside the grooves (401), and then the height and the inclination of the surface of the measured object (400) are measured.