The use of immersion tank processes has steadily decreased over the past decade because of drawbacks associated with material consumption, non-uniform resolution, and the lack of agitation necessary for clearing high-aspect-ratio features for MEMS and advanced lithography. Additionally, increased throughput requirements and reduction in critical dimensions (CDs) have further shifted mainstream applications to single-wafer spray/puddle process flows performed on the track.
The standard configuration of Cee® spray and puddle developers includes two side-spray V-line nozzles to evenly apply developer solution and deionized (DI) water across the substrate simultaneously. An open UHMW polyethylene lid provides spray nozzles mounted either outside the wafer plane, spraying inward from the center of the wafer out (puddle spray), or directly over the substrate for continuous (direct) spray applications. The side spray nozzles are factory positioned outside the wafer plane (side orientation) and ensure uniform deposition for all substrate sizes (2 inches to 200 mm). The spray nozzles can also be used in a puddle developer application by quickly applying material to the substrate at slow spin speeds and then reducing the speed to 0 rpm. During continuous spray applications, the wafer will continue to rotate at a relatively slow velocity.