Semiconductor Edge Bevel Inspection Dual Illumination
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Solution Overview
Problem
The inspection of the Edge & Bevel (E&B) regions in semiconductor wafers is challenging due to the lack of reflected light from these areas under conventional front-side illumination, resulting in fuzzy images and compromised defect detection, especially at the intersection of flat and bevel surfaces.
Innovation Solution
A semiconductor edge and bevel inspection tool system utilizing a dual illumination setup, where a first illumination setup directs radiation towards the wafer edge and bevel region, and a second illumination setup, with different radiation parameters, provides substantially parallel radiation to the imaging sensor, enhancing light collection and image clarity by intersecting with the wafer plane.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If conventional front-side illumination is used, then the inspection process is simple, but the reflected light from edge and bevel regions is insufficient resulting in fuzzy images
Solution Approach 1:
The illumination system is segmented into two distinct illumination setups: a first illumination setup for general wafer inspection and a second illumination setup specifically targeted at the edge and bevel regions. This segmentation allows each illumination source to be optimized for its specific function, with the second setup providing enhanced reflected light collection from challenging geometric areas without complicating the overall system beyond what is necessary.
Solution Approach 2:
The second illumination setup is specifically positioned and configured to target only the edge and bevel regions where reflected light collection is problematic. By applying illumination locally to the problematic areas rather than uniformly across the entire wafer, the system improves image quality where needed while maintaining simplicity elsewhere in the inspection process.
2Measurement precision
If a single illumination source is used, then the device complexity is low, but the image clarity and defect detection precision are compromised
Solution Approach 1:
The single illumination source is segmented into two specialized illumination setups, each optimized for specific inspection requirements. The first illumination setup handles general wafer surface inspection, while the second illumination setup is specifically designed for edge and bevel regions, thereby improving defect detection precision in previously problematic areas.
Solution Approach 2:
The two illumination setups utilize different radiation parameters including distinct wavelengths, incident angles, and intensities. These parameter changes allow optimal illumination conditions for different wafer regions and defect types, enhancing measurement precision without requiring a single overly complex illumination system.
3Manufacturing precision
If front-side illumination is used, then the illumination setup is simple, but the boundary segmentation between flat and bevel areas is unclear
Solution Approach 1:
The second illumination setup is specifically configured to illuminate the boundary regions between flat and bevel areas with optimized incident angles and intensities. This local quality approach ensures that the critical boundary areas receive specialized illumination that enhances contrast and clarity for precise segmentation, while other areas continue to use the simpler first illumination setup.
Solution Approach 2:
Different radiation parameters including wavelength, intensity, and incident angle are applied by the two illumination setups to optimize boundary visualization. The second illumination setup's specific parameters are tuned to enhance the contrast at flat-bevel interfaces, enabling precise manufacturing measurements without requiring complete system redesign.
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 precise segmentation of wafer geometrical dimensions, improved defect detection, and clearer images of the wafer edges and bevels, overcoming the limitations of conventional methods by increasing the collection of reflected light and providing sharper boundaries between flat and bevel areas.
Implementation Method 1
the image sensor collects most of the light reflected from these areas
Implementation Method 2
at least a portion of the second illumination radiation is configured for interacting with at least a portion of the wafer edge and bevel region surface
Data Source
AI summary
The present disclosure relates to a novel semiconductor edge and bevel inspection tool system of a wafer comprising a first illumination setup, an imaging sensor unit, and a second illumination setup. At least a portion of the second illumination radiation is configured for interacting with at least a portion of the wafer edge and bevel region surface. The second illumination setup has different radiation parameters than the first illumination setup. The first and the second illumination radiations have substantially opposite directions.