Fab Load Port Collision Control Using OHT and Maintenance Crane Sensing
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Solution Overview
Problem
In semiconductor fabrication facilities, independent operation of transporting and maintenance devices can lead to collisions at load ports, causing damage and resulting in high costs and downtime due to the lack of effective collision prevention systems.
Innovation Solution
A system with sensors and a control unit is implemented to monitor the locations of maintenance and transporting devices, defining a 'danger zone' around the load port and switching between automatic and manual modes to prevent collisions by disabling the transporting device when the maintenance crane enters the zone.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If transporting and maintenance devices operate independently to improve productivity, then throughput increases, but collision risk at load ports increases causing damage and downtime
Solution Approach 1:
A control unit acts as an intermediary between the transporting device and maintenance device. The control unit receives location data from both devices and coordinates their operations to prevent collisions, enabling independent operation while maintaining safety through centralized mediation.
Solution Approach 2:
The system implements feedback mechanisms where location data from sensors on both transporting and maintenance devices is continuously monitored. This feedback loop enables the control unit to detect potential collision scenarios and adjust device operations accordingly, maintaining reliability while allowing high-speed independent operation.
2Reliability
If sensors and control systems are added to prevent collisions, then safety improves, but device complexity increases
Solution Approach 1:
The control unit serves multiple functions: it monitors location data from both devices, determines collision risk, coordinates device operations, and manages the overall safety system. This multi-functionality reduces the need for separate dedicated components for each safety function, thereby limiting complexity growth while maintaining comprehensive collision prevention.
Data Source
AI summary
A system for a semiconductor fabrication facility includes a maintenance tool, a control unit, a first track, a second track, a maintenance crane movably mounted on the first track, a plurality of first sensors disposed on the first track, an OHT vehicle movably mounted on the second track, and a second sensor on the OHT vehicle. The first sensors detect a location of the maintenance crane and generate a first location data to the control unit. The second sensor generates a second location data to the control unit.