High Performance Removal Technology using Ozone Microbubble

Abstract

The removal technology of single-wafer processing using ozone is proposed on photoresist removal in the semiconductor manufacturing. Ozone is friendly for the environment and no harm to the product. Before now, the authors indicated that disk-shaped nozzle forms a vortex structure between the disks which is considered to cause the reduction of photoresist removal rate. This study proposes a disk-shaped convex nozzle to suppress the vortex. In order to investigate the effects of the presence or absence of the convex, the removal experiments were conducted. As a result, disk-shaped convex nozzle had the higher removal ability than disk-shaped nozzle in the convex part.
Next, as a new removal method, we suggest the ozone microbubble with a Venturi tube. To investigate the performance of the photoresist removal with it, first, the generation of ozone microbubbles is observed in the Venturi tube via a high speed video camera. Next, to clarify the effect of the superficial liquid and gas velocities, the ozone microbubble, and presence or absence of convex, ozone water concentration measurement and photoresist removal experiments were conducted. As a result, the ozone water concentration increased with increasing superficial velocity and the remaining photoresist thickness reduced. Also, ozone microbubble had the higher removal ability than ozone water single-phase. Compared presence and absence of convex, convex influenced photoresist removal efficiently. In addition, compared with the existing study, it is suggested that the superficial liquid and gas velocities and ozone water concentration affect the photoresist removal rate.