Abstract: A system to process semiconductor wafers includes an end effector, a proximity sensor and a controller. The end effector may be adapted to handle a semiconductor wafer. The proximity sensor may be attached to the end effector and may output a first sensor signal if a distance between the end effector and an object separated from the end effector is less than or equal to a first predetermined distance. The controller is responsive to the first sensor signal to slow a movement of the end effector. The proximity sensor further outputs a second sensor signal if the distance between the end effector and the object is less than or equal to a second predetermined distance in which the second predetermined distance being less than the first predetermined distance. The controller is responsive to the second sensor signal to stop movement of the end effector.

Abstract: A system to process semiconductor wafers includes an end effector, a proximity sensor and a controller. The end effector may be adapted to handle a semiconductor wafer. The proximity sensor may be attached to the end effector and may output a first sensor signal if a distance between the end effector and an object separated from the end effector is less than or equal to a first predetermined distance. The controller is responsive to the first sensor signal to slow a movement of the end effector. The proximity sensor further outputs a second sensor signal if the distance between the end effector and the object is less than or equal to a second predetermined distance in which the second predetermined distance being less than the first predetermined distance. The controller is responsive to the second sensor signal to stop movement of the end effector.