THERMAL RAY PREVENTION FILTER FOR FAR ULTRAVIOLET RAY EXPOSURE

摘要

PURPOSE:To form the thermal ray prevention filter by filling NiSO4 aqueous solution between two thin transparent quartz substrates. CONSTITUTION:The quartz windows 5,5' uniform about 0.2 mm thick are attached to the holder 4, NiSO4 aqueous solution flows 7 and it is discharged 8. When this filter is inserted in the optical path of the light concentration and radiation unit, only thermal rays can removed with good efficiency with NiSO4 aqueous solution. Thus, the temperature rise in the exposed test piece at the radiated surface is made slight and the fine pattern can be copied while keeping mask alignment accuracy with high accuracy.