Wafer End Effector Pressure Sensing for Non-Contact Position Detection

The patent replaces optical detection systems with a pressure-based detection system. Instead of using optical sensors that require line-of-sight and become complicated in stacked configurations, the invention uses a vacuum pump connected to a pressure sensor to detect wafer presence through pressure changes in a sealed chamber. This mechanical substitution eliminates the complexity of optical alignment and stacking issues while maintaining reliable detection.

The patent employs pneumatic principles by using a vacuum pump to create a pressure differential for detection. The system seals a chamber with the wafer and uses the vacuum pump to remove air, causing a pressure drop that is detected by a pressure sensor. This pneumatic approach provides simple, reliable detection without the complexity of optical systems, especially in stacked configurations.

The patent uses pneumatic pressure detection to identify wafer presence without physical contact with the wafer's planar surfaces. The vacuum pump creates a pressure differential that is sensed when the wafer seals the chamber, providing non-contact detection that prevents surface contamination while accurately confirming wafer presence and positioning.

The system employs feedback through pressure sensing to confirm wafer presence and positioning. The pressure sensor provides real-time feedback about the pressure differential created when the wafer seals the chamber, enabling the system to verify correct wafer placement without contacting the planar surfaces, thus preventing contamination while ensuring accurate detection.