Automatic OHT Vehicle Cleaning Unit for Particle Contamination Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The handling and transport of 300 mm wafers in semiconductor fabrication facilities pose efficiency challenges due to the generation of particles or debris from friction between OHT vehicle wheels and rails, leading to contamination of sensitive equipment and potential quality issues in wafer manufacturing.
Innovation Solution
An automatic cleaning unit is introduced, equipped with sensors to detect OHT vehicle locations and vacuum cleaning equipment to remove particles from three directions, allowing for automated and efficient cleaning of OHT vehicles without manual intervention.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If OHT vehicles are used to transport wafer carriers, then productivity and automation are improved, but particles are generated from friction between wheels and rails causing contamination
Solution Approach 1:
The patent extracts and removes the harmful particles generated by OHT vehicle wheel-rail friction through vacuum cleaning equipment. The cleaning system selectively removes contaminants from the OHT vehicles without interfering with their transport function, thus maintaining productivity while eliminating the harmful particle generation effect.
Solution Approach 2:
The patent converts the harmful friction particles into a manageable cleaning task by implementing automated vacuum cleaning stations. The particles generated during normal operation are captured and removed at designated cleaning zones, transforming the continuous contamination problem into a controlled periodic cleaning process that maintains overall system cleanliness.
2Object-generated harmful factors
If manual cleaning of OHT vehicles is performed, then particle removal is achieved, but manufacturing downtime increases
Solution Approach 1:
The patent implements self-service cleaning where OHT vehicles are automatically cleaned by vacuum cleaning equipment at designated cleaning zones along their transport path. The vehicles continue their operation autonomously while the cleaning system actively removes particles without requiring manual intervention or taking the vehicles out of service, thus eliminating manufacturing downtime associated with manual cleaning.
Solution Approach 2:
The patent ensures continuous cleaning action by positioning multiple vacuum cleaning units at different zones along the OHT vehicle routes. This allows particles to be removed continuously as vehicles pass through cleaning zones, rather than requiring periodic shutdowns for manual cleaning, thereby maintaining both cleanliness and continuous manufacturing operation.
3Object-generated harmful factors
If vacuum cleaning equipment is installed to remove particles, then cleanliness is improved, but device complexity increases
Solution Approach 1:
The patent designs the vacuum cleaning equipment to serve multiple functions: cleaning OHT vehicles, maintaining cleanroom environment, and potentially cleaning other equipment surfaces. The cleaning system is integrated into the existing facility infrastructure, sharing vacuum sources, control systems, and maintenance protocols across different cleaning applications, thus reducing overall system complexity despite the added cleaning capability.
4Object-generated harmful factors
If frequent cleaning of OHT vehicles is performed, then contamination is reduced, but productivity decreases due to more cleaning cycles
Solution Approach 1:
The patent implements periodic cleaning action where vacuum cleaning is performed at specific intervals or at designated cleaning zones along the OHT vehicle routes, rather than continuous cleaning. This periodic cleaning approach maintains adequate cleanliness levels while minimizing interference with the continuous transport operation, thus preserving manufacturing productivity.
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
The automatic cleaning system significantly reduces manufacturing downtime, improves the cleanliness of OHT vehicles, and maintains a cleaner environment within the semiconductor fabrication facility, thereby ensuring the quality and integrity of wafers being manufactured.
Implementation Method 1
a vacuum cleaner to remove the particles from the OHT vehicle
Data Source
AI summary
An automatic cleaning unit for AMHS includes a plurality of sensors disposed on OHT rails. The sensors are configured to define a cleaning zone and to detect a location of an OHT vehicle. The automatic cleaning unit further includes a vacuum generator and a top cleaning part installed over the OHT rails in the cleaning zone. The top cleaning part is coupled to the vacuum generator. The vacuum generator is turned on to perform a vacuum cleaning operation when the sensors detect the OHT vehicle entering the cleaning zone.