Overlay Mark Detection via Light Intensity Signals
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Solution Overview
Problem
Conventional overlay measurement devices are time-consuming due to the need to center marks within the field of view and correct for optical distortion, especially as technology nodes decrease and more marks need to be measured.
Innovation Solution
An apparatus and method that uses a detection module movable over a substrate to align with marks, acquiring data from stripe groups without relying on optical imaging, reducing the need for precise alignment and image recognition, thus lowering the measurement time and equipment costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional optical imaging devices are used to measure mark positions, then measurement accuracy can be achieved, but measurement time increases significantly due to the need to center marks and perform image recognition
Solution Approach 1:
The patent extracts the essential measurement function from complex optical imaging systems. Instead of using full optical imaging devices that require centering and image recognition, the invention uses a simplified detection module that directly detects mark positions through light intensity signals, eliminating unnecessary components and steps while retaining measurement capability
Solution Approach 2:
The patent replaces the mechanical/optical imaging system with a simpler detection system. Instead of using optical lenses, mirrors, and complex image processing mechanisms, the invention uses a detection module that emits light and measures intensity variations to determine mark positions, substituting a complex optical-mechanical system with a simpler optical-electrical system
2Measurement precision
If precise alignment and fine tuning are performed to place marks at the center of the field of view, then optical distortion effects are eliminated, but the process becomes time-consuming
Solution Approach 1:
The patent removes the requirement for precise alignment and centering by extracting only the essential detection function. The detection module can measure mark positions accurately without needing to center the marks in the field of view, eliminating the time-consuming alignment and fine-tuning steps while maintaining measurement accuracy through direct light intensity measurement
3Manufacturing precision
If more sets of marks are measured to meet decreasing technology node requirements, then measurement completeness improves, but total measurement time increases
Solution Approach 1:
The patent changes the detection parameter from full optical imaging to light intensity measurement. By measuring light intensity at different positions and using the intensity variations to determine mark locations, the system can quickly process multiple mark sets without the time-consuming image recognition process, thereby maintaining measurement completeness while reducing total measurement time
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
The solution significantly reduces the time required to detect marks on a substrate, improves detection efficiency, and lowers the cost of test equipment by eliminating the need for precise alignment and optical imaging, enabling faster and more cost-effective mark detection.
Implementation Method 1
at least one detection unit configured to emit light to a mark and receive the light from the mark
Data Source
AI summary
An apparatus for detecting a mark on a substrate is provided. The mark has a first stripe group and a second stripe group disposed in parallel to each other. The apparatus includes a detection module operative to move over a surface of the substrate. The detection module includes a detection unit for obtaining data from the mark and operative to perform repeated acquisition operations on the first stripe group and the second stripe group of the mark. Each of the acquisition operations acquires data associated with the first stripe group or the second stripe group of the mark. The detection module also includes a positioning unit for aligning the detection unit with the mark.