Patent ID: 8291921

Claim:
An apparatus for removing air bubbles from a fluid, comprising: a delivery passage, in a head, which receives a fluid from a source outside the head; a plenum, in the head, connected to input channels that allow the fluid to flow down from the delivery passage into the plenum, wherein each of the input channels has an inverted V-shaped opening into the plenum to urge any air bubbles in the plenum to flow upwards through the inverted V-shaped opening and wherein each inverted V-shaped opening is directly adjacent to another inverted V-shaped opening; output channels, in the head, that allow the fluid to flow down from the plenum onto a substrate which is a semiconductor wafer; a return passage, in the head, which provides suction from a source outside of the head; and a connecting passage, in the head, which connects the delivery passage and the return passage and which allows an amount of fluid to flow from the delivery passage to the return passage, wherein the amount is small in comparison to the total amount of fluid flowing from the delivery passage to the plenum.