Wafer Edge Crack Detection via Template Differential Imaging

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Solution Overview

Problem

Wafer edge cracks during manufacturing processes can lead to significant waste of production resources as existing methods lack efficient detection techniques.

Innovation Solution

An automatic detection method and system using image processing techniques to create a templet image, compare wafer images, binarize and de-noise differential images, and detect edge cracks, thereby preventing resource wastage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If manual inspection methods are used to detect edge cracks, then detection accuracy may be maintained, but detection speed is slow and production resources are wasted

Engineering Contradiction:

Improvedetection speedVSAvoidedge crack detection accuracy

Core Design Contradiction:

ProductivityVSMeasurement precision

Solution Approach 1:

The patent replaces manual mechanical inspection with an automated image processing system. The system captures wafer images using an imaging device, processes them through multiple stages (integration, differentiation, binarization, de-noising), and automatically detects edge cracks. This substitution dramatically increases detection speed while maintaining high accuracy through algorithmic analysis rather than human judgment.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Productivity

If automated detection systems are implemented, then detection speed increases, but system complexity increases

Engineering Contradiction:

Improvedetection speedVSAvoiddetection system complexity

Core Design Contradiction:

ProductivityVSDevice complexity

Solution Approach 1:

The patent divides the image processing task into distinct sequential stages: image integration to create a template, differentiation to identify variations, binarization to separate defect signals from background, and de-noising to remove interference. Each stage is handled by a dedicated processing module, making the complex system more manageable and easier to implement while achieving high detection speed.

Inventive Principle:

Principle #1Segmentation

3Measurement precision

If multiple image processing steps are applied, then detection accuracy improves, but processing time increases

Engineering Contradiction:

Improveedge crack detection accuracyVSAvoidprocessing time

Core Design Contradiction:

Measurement precisionVSLoss of time

Solution Approach 1:

The patent performs image integration first to create a reference template from multiple wafer images. This preliminary action establishes a baseline that simplifies subsequent differentiation and defect detection steps. By preparing the template in advance, the system reduces the computational burden during actual crack detection, thereby maintaining high accuracy while minimizing processing time.

Inventive Principle:

Principle #10Preliminary action

Data Source

PatentUS11644427B2Automatic detection method and automatic detection system for detecting crack on wafer edges

Publication Date: 2023.05.09 UNITED MICROELECTRONICS CORP

AI summary

An automatic detection method and an automatic detection system for detecting any crack on wafer edges are provided. The automatic detection method includes the following steps. Several wafer images of several wafers are obtained. The wafer images are integrated to create a templet image. Each of the wafer images is compared with the templet image to obtain a differential image. Each of the differential images is binarized. Each of the differential images which are binarized is de-noised. Whether each of the differential images has an edge crack is detected according to pattern of each of the differential images which are de-noised.