Wafer Container Optical Inspection for Inner Surface Defect Detection
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Solution Overview
Problem
Existing inspection methods for wafer containers fail to reliably detect foreign matters and defects on the inner surfaces, relying heavily on visual inspection which is subjective and prone to human error, and there is a need for a more certain and automated method.
Innovation Solution
An inspection apparatus and method using a flat lamp to irradiate a transparent portion of the container with light and a camera to image the inspected area, allowing for the detection of foreign matters and defects through transmitted and reflected light, with optional rotation mechanisms for comprehensive inspection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If visual inspection by inspection operators is used, then the inspection process is simple and low-cost, but the detection reliability and precision are insufficient due to human error and subjectivity
Solution Approach 1:
The patent replaces the mechanical visual inspection system (human operators using lamps and microscopes) with an automated optical inspection system comprising illumination devices, imaging devices, and image processing units. This substitution eliminates human error and subjectivity while maintaining inspection effectiveness through automated image capture and analysis.
Solution Approach 2:
The patent creates optical copies (images) of the container interior surfaces through imaging devices. These copied images are then analyzed by image processing units to detect foreign matters and defects, replacing direct human visual inspection with automated analysis of replicated visual information.
2Area of stationary object
If multiple lamps are used to illuminate different portions of the container, then the inspection coverage is improved, but the device complexity and number of components increase
Solution Approach 1:
The patent divides the container inspection into multiple segments or portions. Different illumination devices are positioned to illuminate specific segments (e.g., bottom face, side faces, inner surfaces) separately. This segmentation allows comprehensive coverage while enabling independent optimization of each illumination zone without requiring a single complex illumination system.
Solution Approach 2:
The patent employs illumination devices positioned in different spatial dimensions and orientations to illuminate various portions of the container. By utilizing three-dimensional spatial arrangement of multiple lamps at different angles and positions, the system achieves comprehensive coverage of complex container geometries including bottom faces, side faces, and inner surfaces.
3Reliability
If the container is rotated during inspection, then the inspection completeness is improved, but the inspection time and process complexity increase
Solution Approach 1:
The patent performs preliminary positioning of the container in optimal orientations before inspection. The container is pre-adjusted to positions where illumination devices and imaging devices can capture all necessary views efficiently. This preliminary action reduces the need for extensive rotation during inspection, maintaining completeness while minimizing time loss.
Solution Approach 2:
The patent implements continuous inspection processes where the container is inspected in a continuous manner rather than through discrete, time-consuming rotation steps. The system maintains continuous illumination and imaging, allowing the inspection to proceed without interruption, thereby reducing total inspection time while ensuring all surfaces are examined.
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
The apparatus and method provide a more certain detection of foreign matters and defects within wafer containers, reducing human error and operator load, ensuring high cleanness for silicon wafers, and enabling higher performance devices.
Implementation Method 1
a flat lamp provided to irradiate a portion to be inspected including at least a part of the transparent portion of the container with light
Implementation Method 2
a camera provided to face the flat lamp across the portion to be inspected of the container and configured to image the portion to be inspected so as to detect a foreign matter and/or a defect
Data Source
AI summary
The present invention is an inspection apparatus for inspecting a container including a light-transmittable transparent portion and configured to house a wafer, the apparatus including: a flat lamp provided to irradiate a portion to be inspected including at least a part of the transparent portion of the container with light; and a camera provided to face the flat lamp across the portion to be inspected of the container and configured to image the portion to be inspected so as to detect a foreign matter and/or a defect in the portion to be inspected of the container. This can provide an inspection apparatus and inspection method that can inspect whether a foreign matter or a defect is present inside a wafer container more certainly than visual inspection by a person.