4111 スピンコーティングにおけるウェーハ上面境界層に及ぼすカップ形状と排気流れの影響(G05-9 回転に伴う流れ,G05 流体工学)  [in Japanese] 4111 A Study on Boundary Layer Flow over a Wafer Surface in Spin Coating System  [in Japanese]

Spin coating is often used for spreading photoresist on a wafer surface and drying photoresist film. In spin coating, the rotating speed in drying process has to be limited because of avoiding the generation of Ekman spiral vortex. But, the photoresist film thickness increases near the wafer edge when the rotating speed is low. In this study, the air flow fields on the wafer surface affected by the exhaust flows were measured by a laser Doppler velocimeter (LDV). Especially, the effects of the exhaust flow rates and new type catch cup (Cup B) on the flow field near the wafer edge are investigated in the case of low rotating speed. As the results of these investigations, it was found that the radial velocity in the Cup B was less than that in the Cup A. It is considered that this is one of the reasons of the reduction of the film thickness increase near the wafer edge in the Cup B.