Abstract: The present invention discloses a method and apparatus for delivering and recycling a liquid such that a substantially air bubble-free liquid flow can be supplied to a process machine and a liquid flow that contains air bubbles can be recycled back into a liquid reservoir for venting away the air bubbles. The method and apparatus is not only capable of supplying air bubble-free liquid to a process machine, but also capable of saving a costly process liquid from being purged out into a waste tank in order to eliminate air bubbles entrapped in the liquid.

Abstract: A safety interlock system and method of unloading a standard manufacturing cassette using a safety interlock system are described which prevent the robotic arm used to unload the cassettes from unloading the cassette unless the cassette is in the proper unloading position. The safety interlock system uses a light beam emitted by a light source and illuminating a light sensitive switch if the cassette is not in the proper unloading position. If the cassette is in the proper unloading position the cassette interrupts the light beam and the light sensitive switch is not illuminated. Illuminating the light sensitive switch energizes a relay primary coil which interrupts power delivered to the electrical control unit of the robotic arm and activates an alarm unit.

Abstract: A hand operated tool for picking up a semiconductor wafer includes a vacuum cylinder with a piston. The user first pushes the piston to its forward most position against the force of a spring and a catch mechanism locks the piston in this position. Later, the user presses a button to release the catch mechanism and allow the piston to move to its rear most position in response to the force of the spring. The motion of the piston creates a suitable vacuum in the front part of the cylinder. A vacuum head is attached to the forward end of the cylinder. It has a generally square flat surface with sides about one third the diameter of a wafer. The user positions this surface in contact with a wafer and then pushes the button to releases the piston and apply a vacuum to grasp the wafer. The user moves the wafer to its destination and then presses a second button to allow air to enter the vacuum side of the cylinder and thereby release the grasp on the wafer.