The removal of contaminants from surfaces is a common task. A common techique used to accomplish this removal is to rinse the surface with air, water, or some other fluid. Differing applications have different constraints on the type of rinsing fluid employed, the flows that are need to accomplish the rinse, and the thoroughess of rinse required.
The rinsing of essentially planar items is one common example of rinsing. In production environments, often many items of similar size and shape must be rinsed. Examples of such environments include semiconductor wafer processing, photographic film processing, and certain precision machined parts. Semiconductor wafer processing poses a particular challenge: large numbers of wafers must be rinsed, the rinse must be very thorough, and the hazardous nature of the contaminants being removed imply that the rinse be accomplished with a minimum of fluid (since the waste fluid carries the contaminants).
Several techniques are currently employed in the rinsing of semiconductor wafers. McConnell, et. al. in U.S. Pat. No. 4,795,497 disclose a fluid treatment system that is kept hydraulically full. Processing fluids can be pumped through the system as well as rinsing fluids. This system proves cumbersome, however, for the rinsing of semiconductor wafers processed by other methods.
Another common method of rinsing semiconductors involves a rinse tank. The wafers are held in a rectangular trough, and the loaded trough is lowered into a tank of deionized water. This approach is straightforward in concept and in implementation, and is applicable in a variety processing systems. This rinsing process, however, does not result in uniformly thorough contaminant removal from the wafers. It also requires excessive quantities of costly deionized water, and results in equally excessive amounts of contaminated water. There is an unmet need for a rinsing system which is efficiently designed to minimize the amounts of rinse fluids used by providing for fairly uniform removal of contaminants from wafer surfaces.