Substrate Cassette Orientation Detection Using Reflective Optics
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Solution Overview
Problem
Existing substrate orientation detection systems face reduced accuracy due to variations in diameter and material of substrates, which affect light transmittance and dimensions, leading to incorrect orientation alignment.
Innovation Solution
A substrate processing apparatus equipped with a reflective optical sensor and a controller that moves the sensor along optical paths to detect orientation indicators on substrates, using reflectors to enhance detection accuracy regardless of substrate type, and a comb-shaped sensor for versatile detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a light transmissive sensor is used to detect substrate orientation, then the detection process is simple, but the detection accuracy decreases when substrates have different diameters and materials
Solution Approach 1:
A reflector is introduced as an intermediary element between the optical sensor and the substrate. The reflector is positioned to reflect light onto the substrate's orientation indicator and redirect the reflected light back to the sensor, enabling accurate detection without the sensor directly viewing the substrate. This mediator approach allows consistent detection across substrates with varying diameters and materials.
Solution Approach 2:
The detection system transitions from direct optical detection to indirect detection via light reflection. By changing the detection dimension from direct line-of-sight to reflected light paths, the system achieves universal applicability across different substrate types while maintaining detection simplicity.
2Measurement precision
If multiple sensors are used to accommodate different substrate types, then the detection accuracy is maintained, but the device complexity increases
Solution Approach 1:
A single optical sensor is designed to perform detection across multiple substrate types by combining it with a reflector mechanism. The reflector adjusts light paths to accommodate different substrate diameters and materials, allowing one sensor to replace what would otherwise require multiple specialized sensors, thereby reducing system complexity while maintaining universal detection capability.
3Device complexity
If the optical sensor is fixed in position, then the device complexity is reduced, but the adaptability to different substrate types decreases
Solution Approach 1:
The reflector is designed with dynamic adjustment capability, allowing it to change its orientation or position to accommodate different substrate types. This dynamic element compensates for variations in substrate diameter and material properties, enabling a fixed sensor position to achieve adaptable detection across diverse substrates without requiring sensor relocation.
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 the accuracy of substrate orientation detection, ensures reliable alignment, and simplifies the detection process by using a single sensor for multiple substrate types, reducing alignment errors and cassette loading time.
Implementation Method 1
a reflective optical sensor configured to emit the light along the optical path and to detect the light reflected from the reflector
Data Source
AI summary
To improve an accuracy of detecting whether an orientation of a substrate is correct, there is provided a technique that includes: a stage where a cassette accommodating substrates is placed, wherein the substrates are provided with orientation indicators; a reflector provided at a first end of an optical path set to enable a light to pass therethrough without hitting the substrates when the orientation indicators of the substrates are oriented in a predetermined direction; a robot configured to transfer the cassette between the stage and a shelf, and including a reflective optical sensor configured to emit the light along the optical path and to detect the light reflected from the reflector; and a controller controlling the robot to move the reflective optical sensor to a position corresponding to the optical path when checking whether the orientation indicators of the substrates on the stage are aligned in the predetermined direction.