OHT-AMR Interface Transport for Flexible Fab Port Access
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Solution Overview
Problem
Existing semiconductor fabrication facilities face limitations in inter-floor and inter-building connections due to overhead hoist transport (OHT) rails being installed on ceilings, leading to congestion and restricted port access, which can be alleviated by introducing an autonomous mobile robot (AMR) as an interface device.
Innovation Solution
A transport system incorporating an OHT and an AMR, where the OHT moves along a ceiling rail and the AMR travels on the floor, with interfaces for communication and control, enabling flexible port access and congestion management.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If interface devices are fixed at a particular location, then the OHT can deliver transport targets, but the OHT must move to that location causing congestion and limited port access
Solution Approach 1:
The patent applies the dynamics principle by making the interface device mobile instead of fixed. The mobile robot moves autonomously to meet the OHT at any location along its travel path, enabling flexible port access without requiring the OHT to travel to a fixed interface location. This resolves the contradiction by allowing the interface device to adapt its position dynamically based on the OHT's current location and task requirements.
Solution Approach 2:
The mobile robot acts as an intermediary between the OHT and the transport target. Instead of the OHT directly accessing fixed ports, the mobile robot serves as a moving interface that can position itself optimally to receive or deliver transport targets. This intermediary approach allows the OHT to maintain its efficient overhead travel while the mobile robot handles the flexible interface operations at various locations.
2Productivity
If multiple transfer commands are concentrated on a limited port, then the interface device can handle transfers, but the OHT becomes congested while moving to the port
Solution Approach 1:
The patent applies segmentation by distributing transfer operations across multiple mobile robots instead of concentrating them at a single fixed port. Each mobile robot can independently handle transfer commands at its current location, dividing the system's transfer workload into parallel segments. This eliminates the bottleneck effect where multiple OHTs would queue at a limited port, reducing system congestion while maintaining high transfer handling capability.
3Productivity
If OHT rails are installed on the ceiling, then the OHT can transport wafers, but inter-floor and inter-building connections are impossible
Solution Approach 1:
The patent applies the dimensionality change principle by transitioning from a two-dimensional ceiling-based OHT system to a three-dimensional system that includes vertical movement. The mobile robot operates on the floor level and can move vertically between floors using elevators or other vertical transport mechanisms. This adds the vertical dimension to the transport system, enabling inter-floor and inter-building connections while the OHT continues to provide efficient horizontal transport on the ceiling level.
Data Source
AI summary
A transport system may include a first transport unit configured to move along a travelling rail installed in a semiconductor fabrication line and transport a transport target, a second transport unit configured to autonomously travel on a floor of the semiconductor fabrication line, in a location lower than the first transport unit, a first interface installed in the first transport unit and configured to identify and communicate with the second transport unit, a second interface installed in the second transport unit and configured to identify and communicate with the first transport unit, and a controller configured to receive signals from the first interface and the second interface, generate and transmit a control signal to the first transport unit and the second transport unit, and control the transport target to be exchanged between the first transport unit and the second transport unit.