Novel coating apparatus using nozzle-scan technique

Scan coating is a technique that coats material like painting on the wafer. In this paper, we introduce the scan coating technology that enables to replace the spin coating. To make film thicker with a smaller volume of dispensed solution, the nozzle diameter was decreased to 20-100 μm. The dispensing time at the outside of wafer was also greatly reduced. Here waste rate is defined as a ratio of wasted materials to all dispensed material, the waste rate is 10% when an acceleration of the nozzle is 200 m/sec². This is nine times less than that for conventional spin coating; its waste rate is 90%. The scan coating has an advantage of pattern coverage on a topological wafer since the dispensed material is not stretched on the wafer by a centrifugal force. Because material´s evaporation is quite low during the scan coating, the temperature change of the wafer is very small. This results in better film thickness uniformity. The scan coating may solve current problems of the spin coating technique such as larger material consumption, coating uniformity on the topological wafers, and wafer temperature control