Wafer Notch Position Detection Using Light Intensity Sensing
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Solution Overview
Problem
Image sensor-based techniques for semiconductor wafer notch positioning detection are prone to high failure rates and false-positive detections due to lighting conditions, limiting their 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 notch position 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
1Adaptability or versatility
If image sensor-based techniques are used for notch positioning detection, then positioning capability is provided, but detection accuracy deteriorates due to lighting conditions causing high failure rates and false-positives
Solution Approach 1:
The patent replaces the image sensor-based optical detection system with a laser-based detection system. A laser beam is projected through the wafer notch, and a photodetector measures the transmitted light intensity. This substitution eliminates the lighting condition sensitivity of image sensors while maintaining positioning capability, thereby resolving the contradiction between adaptability and measurement precision.
2Adaptability or versatility
If image sensor-based techniques are used for notch positioning detection, then positioning capability is provided, but reliability deteriorates due to high failure rates and false-positive detections
Solution Approach 1:
The patent replaces the unreliable image sensor-based detection with a laser-based detection system using a photodetector to measure light transmission through the notch. This substitution provides more consistent and reliable measurements by eliminating the high failure rates and false-positives associated with image sensor-based techniques under varying lighting conditions.
3Adaptability or versatility
If image sensor-based techniques are used for notch positioning detection, then positioning capability is provided, but device complexity increases
Solution Approach 1:
The patent replaces the complex image sensor-based detection system with a simpler laser-based system consisting of a laser source, optical components for beam shaping, and a photodetector. This substitution reduces device complexity while maintaining positioning capability, as the laser system requires fewer processing elements and simpler optical paths compared to image sensors and their associated processing hardware.
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 system enhances detection accuracy, reduces false-positives, and is applicable across a broader range of semiconductor processes, improving wafer yield and reducing scrap rates.
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
Implementation Method 2
a reflector to receive and redirect the beam of light
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.