Abstract: There is described a spin coating apparatus for applying a liquid material to a semiconductor wafer, or the like, that has a spin head for supporting a wafer on the top surface, a motor to rotate the spin head, and a nozzle located over the spin head for dispensing liquid on the wafer mounted on the spin head. A liquid well is provided having a bottom outlet opening, a bottom inlet opening, a top vent opening, and a heat exchange jacket on at least the well side walls. A shut-off valve is located between the nozzle and well, with the inlet of the valve communicating with the bottom outlet of the well, and the inlet of the valve communicating with the nozzle. A liquid supply source provides liquid to the well through the inlet opening of the well. A multi-stage vent and purge system is provided to vent and selectively introduce either gas or liquid cleaning medium into the well through the top vent opening. The distance between the nozzle and the spin head is controlled with a nozzle support.

Abstract: A station for coating a semiconductor wafer with a photoresist is provided with a detector for bubbles that may occur in the resist that is supplied to the wafer. The resist is carried to the coating apparatus by a plastic tube. A commercially available capacitance detector is positioned to detect the dielectric constant of the combination of the tube, the resist, and any bubbles in the resist. The dielectric constant of the bubbles is lower than the dielectric constant of the resist, but the difference is not sufficient for detecting the bubbles with the capacitance detector alone. A metal backing plate is located on the side of the tube opposite the detector and enhances the operation of the detector sufficiently to detect bubbles of various sizes.

Abstract: A method for dispensing fluids on a semiconductor wafer wherein a wafer is mounted on a rotatable chunk, a fluid to be dispensed is introduced into a well through an inlet located adjacent the bottom of the well, rotating the chunk and moving a soft inpact dispensing nozzle, that draws bubble-free fluid from the bottom of the well, over the wafer, and dispensing the fluid at a low pressure and a short distance to the wafer surface.