Substrate Transfer Detection Using Reflected Light for Transparent Wafers
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Solution Overview
Problem
Existing substrate detection sensors struggle to accurately detect transparent substrates due to light transmission issues, leading to erroneous detection.
Innovation Solution
A substrate detection system utilizing a rod-shaped light projector and receiver, with a partition to prevent direct light incidence, allowing optical detection of transparent substrates by reflecting light off their surfaces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a transmission type fiber sensor is used to detect substrates, then the detection mechanism is simple, but transparent substrates cannot be detected accurately because light passes through them without blocking
Solution Approach 1:
The patent inverts the detection principle from transmission type to reflection type. Instead of detecting light that passes through the substrate, the system detects light reflected from the substrate surface. The light source and sensor are positioned to illuminate the substrate at an angle and detect the reflected light, enabling accurate detection of transparent substrates that would otherwise be invisible to transmission sensors.
Solution Approach 2:
The patent introduces a reflection surface as an intermediary between the light source and sensor. By positioning the light source and sensor at specific angles relative to the substrate, the system uses the substrate's reflective properties (even for transparent materials) to generate a detectable signal. The angled illumination creates a reflection pattern that the sensor can detect, serving as an intermediary mechanism to make transparent substrates visible.
2Productivity
If multiple substrate transfer plates are used to transfer multiple substrates simultaneously, then productivity increases, but the complexity of the detection system increases due to requiring multiple sensors
Solution Approach 1:
The patent makes the detection system universal by designing a reflection-type sensor that can detect all substrate types (transparent and opaque) using the same detection mechanism. This single universal detection approach replaces the need for different sensor types or multiple specialized sensors, reducing system complexity while maintaining the capability to monitor multiple substrate transfer plates simultaneously.
3Reliability
If a substrate detection sensor is installed for each substrate transfer plate, then detection coverage is complete, but the device complexity and cost increase
Solution Approach 1:
The patent creates a universal detection mechanism that can serve multiple substrate transfer plates with a single sensor design. The reflection-type sensor positioned at an angle can monitor multiple plates simultaneously or sequentially, eliminating the need to install separate transmission sensors on each plate. This reduces the total number of sensors while maintaining complete detection coverage across all transfer plates.
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 accurate detection of transparent substrates, reduces false positives, and maintains detection accuracy even with varying substrate pitches and configurations.
Implementation Method 1
a light projector formed in a rod-shape and including a first end configured to emit a reference light from a first optical fiber
Implementation Method 2
a light receiver formed in a rod-shape and including a second end which substantially faces the first end and is configured to receive the reference light reflected by a rear surface or a front surface of the corresponding substrate, which is transparent
Data Source
AI summary
There is provided a technique that includes: (a) at least one end effector configured to be capable of being inserted into a holder configured to accommodate a plurality of substrates in multiple stages without being in contact with the plurality of substrates, and gripping a corresponding substrate of the plurality of substrates respectively; and (b) at least one substrate detector arranged at a predetermined relative position with respect to the at least one end effector and configured to be capable of optically detecting the corresponding substrate in at least one selected from the group of a state in which the at least one end effector is inserted into the holder and a state in which the at least one end effector grips the corresponding substrate.