Study on DHP temperature effect in PSPI exposure process

PSPI has been applied to the end-fab process for better efficiency. However, it causes process time to increase, which can be a serious problem in the photo process. Excessive exposure time results in lower efficiency and lower productivity as well. It is also blamed for a damage of expensive equipment lens. Existing countermeasures have yet to clear those problems. As an alternative, DHP temperature control is expected to reduce exposure time by adjusting the hardness of PSPI. Consequently, exposure time per shot can be sharply reduced, enhancing productivity of photo process where many shots are repeatedly exposed to a wafer.