Load Port Mapping Sensors for Non-Circular Wafer Detection
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Solution Overview
Problem
Conventional load port mapping mechanisms struggle to accurately detect the presence and posture of non-circular transfer target objects, such as rectangular or large-sized wafers, due to spatial constraints and increased equipment costs associated with imaging systems.
Innovation Solution
A load port equipped with two mapping sensors that move up and down integrally or independently with the load port door, capable of detecting the end surface of transfer target objects without imaging, allowing for accurate detection of presence and posture without the need for image processing, and reducing system costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If imaging systems are used to detect non-circular transfer target objects, then detection accuracy is improved, but system cost increases
Solution Approach 1:
The patent replaces complex imaging systems with a simpler optical detection system using transmissive optical sensors. Instead of using cameras and image processing algorithms, the invention uses optical sensors that detect light transmission through the wafer edge, substituting a mechanical/optical system for a more complex imaging system while maintaining detection capability for non-circular objects.
Solution Approach 2:
The patent employs inexpensive optical sensors rather than expensive imaging systems. The transmissive optical sensors used are simpler and more cost-effective components that can accurately detect wafer presence and posture without requiring the complex infrastructure of imaging systems, including cameras, lighting, and processing hardware.
2Measurement precision
If imaging systems are used to detect transfer target objects, then detection capability is improved, but processing time increases
Solution Approach 1:
The patent replaces time-consuming image processing with immediate optical detection. The transmissive optical sensors provide real-time detection of wafer presence and posture by measuring light transmission, eliminating the need for capturing, processing, and analyzing images, thus significantly reducing processing time while maintaining detection capability.
Solution Approach 2:
The patent skips the intermediate step of image processing by directly detecting wafer characteristics through optical transmission. Instead of capturing an image and then processing it to extract information about wafer presence and posture, the system directly measures the optical properties to determine detection parameters, rushing through the detection process in a single step.
3Measurement precision
If mapping sensor enters FOUP to detect transfer target objects, then detection accuracy is improved, but device complexity increases
Solution Approach 1:
The patent makes the load port door serve multiple functions: it acts as both a closure for the load port and as a mounting platform for the mapping sensor. The door's inner surface is utilized as a functional surface for sensor placement, allowing the same structural component to fulfill both sealing and detection functions, thereby reducing the need for additional dedicated sensor housing or positioning mechanisms.
Solution Approach 2:
The patent combines the mapping sensor positioning system with the load port door mechanism. Instead of having a separate movable platform or robotic arm to position the sensor inside the FOUP, the sensor is integrated onto the door itself, merging the door's movement function with the sensor's positioning function. This reduces equipment complexity by eliminating redundant positioning mechanisms.
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 transfer target objects with rectangular plan-view shapes and large sizes, reducing processing time and maintaining low system costs by eliminating the need for imaging and image processing.
Implementation Method 1
capable of detecting an end surface Wa of a transfer target object W by irradiating detection waves toward an inside of the storage container
Implementation Method 2
two mapping sensors M1 and M2... capable of detecting an end surface Wa of a transfer target object W by irradiating detection waves
Data Source
AI summary
There is provided a load port, including: a frame including an opening via which a transfer target object is capable of passing in a substantially horizontal posture; a load port door configured to engage with a container door capable of opening and closing a loading/unloading port of a storage container including slots capable of accommodating the transfer target object in a multi-stage manner, and to open and close the opening of the frame; and a mapping mechanism configured to map information on an accommodation state including presence or absence of the transfer target object in each of the slots in the storage container via the opening and the loading/unloading port.