Wafer Hoist Belt Tension Sensing for Load Port Alignment
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Solution Overview
Problem
Current wafer transport systems face challenges in achieving precise alignment and attitude inspection between wafer container units and load ports, leading to inefficient and potentially damaging handling of wafers during transportation in semiconductor fabrication facilities.
Innovation Solution
A wafer transport system with a network of transport rails and a wafer transport device equipped with a marking scanner, controller, and adjustable hoist unit, which uses belt winding drums and tension sensors to align and adjust the hoist unit's attitude to match the load port's orientation, ensuring smooth loading and unloading of wafers while preventing damage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If automated handling systems transport wafer container units between process bays, then productivity is improved, but alignment precision between wafer container units and load ports deteriorates
Solution Approach 1:
The patent replaces manual alignment procedures with an automated optical measurement system. A scanner device with light sources and sensors automatically detects the position and orientation of the wafer container unit relative to the load port, eliminating the need for manual mechanical alignment while maintaining high precision.
Solution Approach 2:
The system implements a feedback mechanism where the scanner continuously monitors the alignment status between the wafer container unit and load port during transport. The automated handling system receives real-time alignment data and makes dynamic adjustments to maintain precise positioning, enabling both high productivity and measurement precision.
2Productivity
If automated handling systems move wafer container units quickly, then productivity is improved, but wafer integrity deteriorates due to potential misalignment damage
Solution Approach 1:
The scanner device performs alignment verification before the wafer container unit is engaged with the load port. This preliminary alignment check ensures that the container is properly positioned in advance, preventing misalignment damage during the high-speed transport and loading operations.
Solution Approach 2:
The patent replaces slow manual alignment verification with rapid automated optical scanning. The scanner quickly captures position and orientation data, enabling the system to verify alignment and proceed with high-speed transport, thus maintaining both productivity and wafer integrity.
3Measurement precision
If manual alignment methods are used between wafer container units and load ports, then alignment precision is improved, but productivity deteriorates
Solution Approach 1:
The patent substitutes manual alignment operations with an automated optical scanning and control system. The scanner rapidly captures alignment data, and the automated handling system processes this information to achieve precise positioning, maintaining high alignment accuracy while eliminating the time-consuming nature of manual procedures.
Solution Approach 2:
The alignment measurement process is integrated into the continuous transport operation. The scanner operates continuously during the approach and positioning phases, allowing alignment verification to occur without interrupting the overall transport flow, thus maintaining both precision and productivity.
Data Source
AI summary
A method includes moving a wafer transport device to a position above a load port; lowering a hoist unit of the wafer transport device above the load port, wherein the wafer transport device has a plurality of belts, each of the belts is connected to the hoist unit and wound around a respective belt winding drum; detecting sound waves from the belts by using at least one acoustic sensor to measure tensions of the belts; and comparing the tensions from the belts to determine an inclination of the hoist unit.