Wafer Image Equalization for Clearer Defect Detection
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Solution Overview
Problem
Wafer images often blend typical defects into the background, making them difficult to detect manually, leading to inefficiencies in defect identification and increased time consumption.
Innovation Solution
A method and apparatus for wafer image equalization involving conversion to bitmap data, generation of grayscale distributions and cumulative probability distributions, application of mapping functions to equalize grayscale values, and generation of an equalized wafer image to enhance defect visibility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If manual inspection of wafer images is performed, then defect detection can be conducted, but inspection time and labor costs increase significantly
Solution Approach 1:
The patent replaces manual visual inspection with automated image processing techniques. The system converts wafer images into bitmap data, generates grayscale distributions, creates cumulative probability distributions, and applies mapping functions to equalize the grayscale distribution. This automated processing enables rapid defect detection without human intervention, directly resolving the contradiction between detection capability and inspection time.
2Measurement precision
If wafer images are processed to enhance defect visibility, then defect detection improves, but image processing complexity increases
Solution Approach 1:
The patent segments the image processing into distinct sequential steps: converting images to bitmap data, generating grayscale distributions, creating cumulative probability distributions, and applying mapping functions. Each step processes a specific aspect of the image data independently, making the overall complex process manageable and systematic. This segmentation approach enhances defect visibility while maintaining processing clarity.
Solution Approach 2:
The patent transforms the image by changing parameter distributions - specifically, it modifies the grayscale distribution of pixel values. By generating cumulative probability distributions and creating mapping functions that equalize the grayscale distribution, the system changes the parameter space of the image data to enhance defect contrast and visibility without requiring complex multi-stage processing.
Data Source
AI summary
A method for wafer image equalization includes obtaining a wafer image, converting the wafer image into bitmap data, generating a grayscale distribution of RGB pixels according to the bitmap data, generating a grayscale cumulative probability distribution of the RGB pixels according to the grayscale distribution, generating a mapping function according to the grayscale cumulative probability distribution of the RGB pixels, converting the grayscale distribution of the RGB pixels by the mapping function into an equalized grayscale distribution of the RGB pixels, and generating an equalized wafer image according to the equalized grayscale distribution of the RGB pixels.