Wafer Notch Position Detection Using Laser Beam Transmission
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Solution Overview
Problem
Image sensor-based notch positioning detection in semiconductor wafer processing is prone to high failure rates and false-positive detections due to lighting conditions, limiting its applicability and increasing semiconductor wafer scrap.
Innovation Solution
A position detection device using a beam of light, comprising a light source, reflector, light gate, and light sensor, determines the position of a semiconductor wafer notch by analyzing the intensity of the light beam, reducing susceptibility to lighting conditions and complexity compared to image sensor-based methods.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If image sensor-based notch positioning detection is used, then positioning detection capability is provided, but detection reliability deteriorates due to high failure rates and false-positives from lighting conditions
Solution Approach 1:
The patent replaces the image sensor-based optical detection system with a laser-based detection system. A laser beam is directed through the wafer notch to a light sensor, eliminating the need for complex image processing and reducing susceptibility to ambient lighting conditions. This substitution of detection methodology resolves the contradiction by providing reliable positioning detection without the high failure rates associated with image sensor approaches.
2Loss of information
If image sensor-based detection is used, then positioning information can be obtained, but device complexity increases leading to higher resource requirements
Solution Approach 1:
The patent extracts only the essential positioning information by using a simple laser beam transmission method through the notch. Instead of capturing and processing entire images, the system measures only the light intensity transmitted through the notch position, significantly reducing computational complexity and resource requirements while still obtaining accurate positioning data.
Solution Approach 2:
The patent employs a simple, low-cost laser diode and light sensor arrangement instead of expensive image sensors and processing hardware. This simplified detection system reduces device complexity and resource requirements while maintaining effective notch positioning detection capability.
3Measurement precision
If image sensor-based methods are used, then detection capability is provided, but semiconductor wafer scrap increases due to false-positive detections
Solution Approach 1:
By replacing the image sensor-based system with a laser transmission system, the patent eliminates the source of false-positive detections. The laser method provides direct, unambiguous measurement of notch position based on light transmission characteristics, preventing incorrect acceptance of mispositioned wafers and thereby reducing wafer scrap.
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 light-based detection system reduces detection errors and false-positives, allowing for broader application across semiconductor manufacturing processes with lower resource requirements, thereby improving semiconductor wafer yield and reducing scrap.
Implementation Method 1
a light sensor to receive a portion of the beam of light after the beam of light travels through the opening, and to convert the portion of the beam of light to a signal
Data Source
AI summary
An optical system may include a light source to provide a beam of light. The optical system may include a reflector to receive and redirect the beam of light. The optical system may include a light gate having an opening to permit the beam of light, from the reflector, to travel through the opening. The optical system may include a light sensor to receive a portion of the beam of light after the beam of light travels through the opening, and convert the portion of the beam of light to a signal. The optical system may include a processing device to determine whether a notch of a wafer is in an allowable position based on the signal.