Substrate Edge Inspection Using Optical Diffraction Patterns
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Solution Overview
Problem
Current methods for inspecting defects on the edge region of substrates, such as optical, laser scan, and ultrasonic inspections, are inadequate in detecting defects accurately and efficiently.
Innovation Solution
A substrate inspection apparatus and method using an optical diffraction pattern to inspect defects on the edge region, employing multiple light generators and detectors to analyze diffraction patterns generated by light beams parallel to the substrate surface.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If optical inspection, laser scan inspection, or ultrasonic inspection methods are used to detect defects on the edge region of the substrate, then some defects can be detected, but the inspection accuracy and efficiency are insufficient
Solution Approach 1:
The inspection system segments the substrate inspection into two distinct parts: center region inspection and edge region inspection. Different inspection methods are applied to each region - optical/laser/ultrasonic methods for the center region, and diffraction-based methods specifically for the edge region. This segmentation allows each method to be optimized for its specific region, improving overall inspection accuracy and efficiency.
Solution Approach 2:
The patent changes the inspection parameter from direct optical detection to diffraction pattern detection for edge region inspection. By using light diffraction patterns generated at the substrate edge, the system achieves higher sensitivity for detecting edge defects while maintaining inspection speed, thus resolving the contradiction between accuracy and efficiency.
2Measurement precision
If multiple inspection methods are used to improve defect detection accuracy, then inspection accuracy improves, but device complexity and inspection time increase
Solution Approach 1:
The patent applies local quality by using different inspection methods for different regions of the substrate. The edge region, which has unique inspection challenges, receives specialized diffraction-based inspection, while the center region uses conventional methods. This localized approach improves accuracy where needed without unnecessarily complicating the entire inspection system.
Solution Approach 2:
By segmenting the inspection task by region rather than applying multiple methods to the entire substrate, the system reduces overall complexity. Each segmented region uses the most appropriate single method, avoiding the need to integrate and manage multiple complex inspection systems across the whole substrate.
3Ease of manufacture
If conventional inspection methods are used for the entire substrate, then the inspection process is simple, but edge region defects cannot be detected accurately
Solution Approach 1:
The patent implements local quality by applying specialized diffraction-based inspection specifically to the edge region where conventional methods fail. The rest of the substrate continues to use simple conventional inspection methods. This targeted approach maintains overall process simplicity while dramatically improving edge region detection accuracy.
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
Improves inspection accuracy and efficiency by detecting various types of defects through sensitive diffraction pattern analysis, enhancing productivity and accuracy of defect detection on substrate edges.
Implementation Method 1
a substrate inspection apparatus configured to examine whether there is a failure on an edge region of a substrate using an optical diffraction pattern
Data Source
AI summary
A substrate inspection apparatus may include: a plurality of inspection units, each of the plurality of inspection units including a light generator and a detector; a support configured to support and rotate a substrate; and an analyzer connected to the detector of each of the plurality of inspection units and configured to analyze an input obtained from the detector, wherein, in a plan view, the substrate includes a center region and an edge region enclosing the center region, wherein the light generator of each of the plurality of inspection units is configured to emit light toward the edge region of the substrate, wherein the detector of each of the plurality of inspection units is configured to detect the light that is emitted towards the edge region of the substrate, and wherein each of the plurality of inspection units extends parallel to a top surface of the substrate.