Overlay Measurement Using Optical Projection and Stripe Detection
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional overlay measurement devices require time-consuming processes to center marks within the field of view, leading to prolonged measurement times due to lens distortion and precise alignment requirements, especially as technology nodes decrease and the number of marks to be measured increases.
Innovation Solution
An apparatus and method that includes a detection module movable over a substrate to detect marks with parallel stripe groups, using a processing module to determine deviations without relying on optical imaging, eliminating the need for centering and precise alignment, and allowing for simultaneous detection of multiple marks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If optical imaging device is used to measure marks, then measurement precision can be achieved, but measurement time increases due to lens distortion and centering requirements
Solution Approach 1:
The patent extracts the marks from their original positions and projects them onto a common measurement plane using optical projection. This allows multiple marks to be measured simultaneously without requiring individual centering, eliminating the time-consuming centering process while maintaining measurement precision through the projection geometry
Solution Approach 2:
The patent merges multiple mark measurements into a single optical field of view by projecting them onto a common plane. This combining approach enables simultaneous measurement of multiple marks, dramatically reducing total measurement time while maintaining precision through the unified measurement reference frame
2Measurement precision
If marks are centered in field of view to eliminate lens distortion, then measurement accuracy improves, but operation complexity and time increase
Solution Approach 1:
Instead of moving the marks to the center of the field of view, the patent inverts the approach by projecting all marks onto a common measurement plane where their relative positions are preserved. This eliminates the need for individual centering operations while maintaining measurement accuracy through the projection geometry
Solution Approach 2:
The patent creates an optical copy of the marks on a common measurement plane through projection. This copied representation preserves the relative positional relationships of marks while eliminating the need for physical repositioning or centering operations, simplifying the measurement process
3Reliability
If multiple sets of marks are measured sequentially, then comprehensive overlay data is obtained, but productivity decreases
Solution Approach 1:
The patent merges multiple mark measurements into a single optical field of view, allowing simultaneous capture and measurement of multiple marks. This combining approach maintains comprehensive overlay data collection while dramatically increasing measurement throughput by eliminating sequential measurement requirements
Solution Approach 2:
The patent enables continuous measurement of multiple marks in a single optical capture event. By projecting all marks onto a common plane, the system maintains continuous useful action across all marks simultaneously, eliminating the interruptions and sequential processing that reduce productivity
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
Significantly reduces mark detection time and cost while improving efficiency and throughput by eliminating the need for precise alignment and optical imaging-based centering, enabling faster and more cost-effective measurement of multiple marks on substrates.
Implementation Method 1
a detection unit configured to obtain data of a mark and perform repeated acquisition operations to obtain data associated with the first stripe group and data associated with the second stripe group
Data Source
AI summary
An apparatus for detecting a mark having first and second stripe groups on a substrate includes a detection module moveable over a surface of the substrate. The detection module includes a detection unit and a positioning unit configured to align the detection unit with the mark. The detection unit is configured to obtain data of the mark and operative to perform repeated acquisition operations on the first and second stripe groups of the mark. Each of the acquisition operations acquires data associated with the first stripe group or the second stripe group. The apparatus also includes a processing module configured to determine a positional deviation between the first stripe group and the second stripe group in response to the obtained data of the mark and data associated with a motion of the detection module.