Wafer Edge Shape Analysis via Electron Microscopy Image Processing
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Solution Overview
Problem
Conventional methods for analyzing the shape of a wafer edge require expensive equipment and precise alignment, making them cumbersome and impractical for high-resolution curvature analysis, which can lead to non-uniform photoresist coating during semiconductor device manufacturing.
Innovation Solution
A method and apparatus using image processing techniques to analyze the shape of a wafer by acquiring high-resolution sectional images with an electron microscope, enhancing contrast, and determining surface contours through luminance differences to calculate shape analysis data, including curvature and gap area, without the need for separate measuring apparatuses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional optical methods (laser scattering) are used to analyze wafer edge shape, then measurement capability is provided, but equipment cost and alignment complexity increase significantly
Solution Approach 1:
The patent uses optical imaging to create a visual copy of the wafer edge profile, which is then processed through image analysis algorithms to extract curvature information. This replaces the need for direct physical measurement with laser scattering, achieving accurate curvature analysis through digital image processing instead of complex optical alignment
Solution Approach 2:
The patent replaces the mechanical/optical alignment system (laser scattering apparatus) with an image processing system. By substituting physical measurement mechanisms with computational image analysis, the system achieves comparable measurement precision while eliminating alignment complexity
2Measurement precision
If conventional optical methods with small laser spots are used, then precise curvature analysis is achieved, but equipment cost and operational burden increase
Solution Approach 1:
The patent creates a digital replica of the wafer edge through optical imaging, allowing precise curvature analysis to be performed on the image copy rather than requiring direct interaction with the physical wafer using complex laser systems. This approach maintains measurement precision while simplifying equipment implementation
Solution Approach 2:
The patent changes the measurement parameter from direct physical measurement (laser spot interaction) to image-based measurement. By transforming the measurement approach from physical to optical-digital, the system achieves precise curvature analysis while significantly easing equipment implementation requirements
3Ease of operation
If high-resolution image processing is used to analyze wafer shape, then analysis simplicity is improved, but image acquisition resolution requirements increase
Solution Approach 1:
The patent segments the wafer edge analysis into distinct processing stages: image acquisition, edge detection, coordinate extraction, and curvature calculation. This segmentation allows the use of standard-resolution imaging equipment combined with sophisticated multi-step image processing algorithms to achieve high measurement precision without requiring ultra-high-resolution cameras
4Measurement precision
If separate measuring apparatuses are used for wafer shape analysis, then measurement capability is provided, but device complexity and cost increase
Solution Approach 1:
The patent merges the shape measurement function with existing optical imaging systems used in semiconductor manufacturing. By combining curvature analysis capabilities with standard optical microscopes or inspection systems, the patent eliminates the need for separate dedicated measuring apparatuses while maintaining measurement precision
Solution Approach 2:
The patent makes existing optical imaging systems multi-functional by adding image processing capabilities that enable curvature analysis. Instead of requiring specialized single-purpose measurement devices, the system allows standard optical equipment to perform both imaging and precise shape measurement functions
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
Enables precise and efficient shape analysis of wafer edges and their vicinity, allowing for accurate representation of curvature and other shape factors, thereby improving the uniformity of photoresist coating and enhancing semiconductor device manufacturing yields.
Implementation Method 1
The acquiring of the sectional image may include capturing the edge and the edge vicinity of the wafer using an electron microscope
Implementation Method 2
The finding of the series of coordinates of the surface contour includes obtaining a luminance of each pixel in the sectional image, obtaining luminance differences between adjacent pixels, determining temporary contour pixels using the luminance differences
Data Source
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AI summary
A method for analyzing the shape of a wafer according to an embodiment comprises the steps of: acquiring a sectional image showing a wafer to be analyzed; finding a coordinate row of the surface contour of the wafer in the sectional image; and obtaining shape analysis data, including information about the shape of the wafer, using the coordinate row.