| 摘要 |
PURPOSE:To prevent a resist from dropping by coating the outer periphery of a nozzle for dropping the resist with the second fine tube, and holding the tube under a reduced pressure to attract the modified substance at the end of the nozzle at the resist dropping time. CONSTITUTION:The periphery of a dropping nozzle 2 is coated by the second fine tube 7. The difference between the outer diameter of the nozzle 2 and the inner diameter of the tube 7 is approx. 1-0.4mm.. The end of the nozzle 2 is retracted approx. 1mm. from the end of the tube 7, and siffuciently coated by the tube 7. The tube 7 is reduced under pressure to approx. 500mm.Hg, and held. According to this construction, modified resist (a) in the nozzle is discharged from the nozzle when dropping to next wafer, but since the discharging pressure is first small, most is attracted to the tube 7 at the end of the nozzle 2 not to drop onto the wafer, and the resist crept to the outer periphery of the nozzle after dropping is finished is immediately attracted to reduce the contamination of the nozzle. Thus, the uniformity of the thickness of the resist film on the wafer can be remarkably improved. |
