| 摘要 |
PURPOSE:To make the thickness of a resin coat on a sheet uniform by applying a photosensitive resin to the periphery by means of a centrifugal force generated by the rotation of a sheet and controlling resin viscosity through application of ultrasound. CONSTITUTION:A wafer 1 fixed through suction to the surface of a chuck 2 is permitted to rotate by a drive mechanism 4 as indicated by an arrow, and at the same time different frequencies preset by means of a frequency control circuit 6 are applied to the wafer 1 from three piezos 7a-7c of a high frequency supply mechanism 5. When a resist is permitted to drop the center of the wafer 1 from a nozzle 3 under this state, the resist is applied in a radial direction to the periphery on the plane of the wafer by means of a centrifugal force generated by the rotation of the wafer 1. The viscosity of the resin is in inverse proportion to the frequency level. Therefore, the viscosity of photosensitive resin is increased by lowering the level of a frequency applied to each piezo 7a-7c in such a manner that the lowering rate is increased proportionately to the periphery. Thus the viscosity of photosensitive resin on the periphery is increased and the coat thickness made uniform. |
