Wafer Wobbling Detection via Reflection Imaging During Rotation
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Solution Overview
Problem
Existing semiconductor processing technologies struggle to detect wobbling of wafers in real-time during high-speed rotation, leading to potential operational errors and the need for unnecessary wafer discarding.
Innovation Solution
A method and system utilizing a camera and machine vision analysis to detect wobbling by analyzing the reflection image of a fixture on the wafer surface, setting regions to calculate the proportion of the reflection image, and determining abnormal wobbling based on predefined upper limit values.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If real-time wafer wobbling detection is implemented during high-speed rotation, then operational errors can be detected immediately and wafer wastage reduced, but device complexity and measurement difficulty increase
Solution Approach 1:
The patent uses optical copying by capturing reflection images of the fixture on the wafer surface to detect wobbling, instead of directly measuring the wafer rotation. This creates an optical copy of the wafer's rotational state through the reflected fixture image, enabling indirect but accurate measurement that reduces direct measurement complexity
Solution Approach 2:
The patent introduces a fixture as an intermediary object mounted on the wafer, whose reflection serves as a mediator to transmit wobbling information. The camera detects the fixture's reflection image rather than directly observing the wafer, using this intermediary to simplify the detection mechanism while maintaining detection accuracy
2Reliability
If maintenance is performed based on preventive maintenance schedules, then device reliability is maintained, but operational errors occurring between maintenance cycles cannot be detected and all wafers must be discarded
Solution Approach 1:
The patent implements real-time feedback by continuously monitoring the wafer's rotation through the reflection image and providing immediate detection of wobbling abnormalities. This feedback loop allows operational errors to be detected during wafer processing rather than waiting for scheduled maintenance, enabling selective discarding of only affected wafers
Solution Approach 2:
The patent performs preliminary detection of wobbling during the wafer processing operation itself, before the wafer is completely processed. This preliminary action allows identification of problematic wafers early in the process, preventing further waste of processing resources on defective wafers while maintaining device reliability
3Productivity
If high-speed wafer rotation is used for efficient processing, then productivity increases, but wobbling occurs due to vibration and mounting errors
Solution Approach 1:
The patent replaces direct mechanical measurement of wafer rotation stability with an optical measurement system. Instead of using mechanical sensors that would interfere with high-speed rotation, the system uses optical reflection imaging to detect wobbling, allowing high-speed operation to continue while monitoring stability
Solution Approach 2:
The patent utilizes the wafer's own reflective surface and the fixture mounted on it to generate the detection signal. The wafer's rotation and wobbling automatically create the motion in the reflection image that is being detected, so the system uses the wafer's own operational characteristics as the measurement mechanism without requiring separate measurement devices
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
Enables real-time detection of wafer wobbling during semiconductor processing, allowing for immediate control actions such as stopping the device when abnormal wobbling occurs, thereby preventing operational errors and reducing wafer wastage.
Implementation Method 1
securing a wafer surface image such that a reflection image which is reflecting a fixture and which is positioned on a surface of a wafer is included in the wafer surface image
Data Source
AI summary
Proposed are a wafer wobbling detection method and a wafer wobbling detection system, the method and the system being applied to a semiconductor processing device that performs a process while a wafer is rotated. The method includes securing a wafer surface image such that a reflection image which is reflecting a fixture and which is positioned on a surface of a wafer is included in the wafer surface image and detecting wobbling by analyzing the reflection image in the secured image, the reflection image being moved due to wobbling. In the system, a photographed image of a rotating wafer is analyzed with machine vision, so that wafer wobbling may be detected during a process for the wafer is performed. In addition, such as stopping the device in real time when abnormal wobbling occurs may be performed since wafer wobbling may be detected while the process for the wafer is performed.