Bidirectional Wafer Pod with Double Rail OHT for Compact Transfer
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Solution Overview
Problem
Existing wafer transfer systems require more time and space due to the need for a single path that must pass through two loading ports sequentially and require a wider space for operation with a fixed radius turnabout section.
Innovation Solution
A bidirectional wafer carrying pod and transfer system with a double rail section and divergent track junction, allowing the pod to be selectively transferred to either sub-track, reducing the need for a turnabout section and enabling simultaneous access to two loading ports from either side, thus reducing transfer time and space requirements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a single rail OHT with fixed radius turnabout section is used, then the system can transfer FOUP through overhead, but the distance between rail ends increases and wider space is required for operation
Solution Approach 1:
The rail system is divided into multiple sections: a first rail section, a second rail section, and a third rail section. The first and second rail sections are arranged parallel to each other, while the third rail section connects them at an angle. This segmentation allows the system to avoid large-radius turnabout sections, reducing the overall operation space while maintaining transfer functionality.
Solution Approach 2:
The invention transitions from a single-plane rail configuration to a multi-dimensional arrangement by introducing parallel rail sections and angled connecting sections. This spatial reconfiguration enables the transport vehicle to change direction more compactly, reducing the horizontal space required for turnabout operations.
2Device complexity
If a single path is designed for single rail OHT to pass through loading ports, then the system structure is simple, but more time is required for transferring FOUP between loading ports
Solution Approach 1:
The transport vehicle is equipped with selective door opening capability, allowing it to dynamically choose which door (first or second) to open based on the destination loading port. This dynamic adaptability enables the vehicle to take optimal paths and perform simultaneous operations, reducing transfer time without requiring complex additional infrastructure.
Solution Approach 2:
The system changes the operational parameter of door selection (first door or second door) based on the destination loading port. By allowing the transport vehicle to selectively open different doors and transfer FOUP to different loading ports, the system achieves parallel operation capability, effectively reducing transfer time while maintaining relatively simple rail structure.
Data Source
AI summary
A wafer transfer system includes a bidirectional wafer carrying pod, an over-head transport (OHT) rail, an OHT, two platforms, and two loading ports respectively connected to the two platforms. The bidirectional wafer carrying pod has a loading housing and two doors respectively and detachably installed on the two opposite sides of the loading housing. The OHT rail has a single rail section and a double rail section. The two ends of the double rail section are connected to the single rail section. The platforms are respectively disposed beside the double rail section. The loading ports are disposed under the double rail section. Through the OHT, The bidirectional wafer carrying pod can selectively be transferred to one rail of the double rail section and disposed on the loading port of the tool corresponding to the one rail of the double rail section.