Magnetic Levitation Positioning Stages for Molecular Cleanliness

Abstract:
A new quality of cleanliness is required for the new extreme ultraviolet lithography (EUVL) and wafer inspection equipment. For some processes, molecular cleanliness is necessary. The magnetic levitation technology is suitable for these requirements. It will be shown that the movable stage can be stabilized and moved in space without any friction. In the last three decades, there were a lot of advantages for new cable designs with very low particle generation during motion. But the outgassing and absolute particle free movement of cables can’t be guaranteed. With the proposed and tested magnetic levitation positioning stages, a cable-free configuration can be used. The magnetic levitation technology has the advantage to isolate the two parts of the levitation stage: the stator isolated with a glass plate from the movable stage part. Both parts can be placed in the two sections and separated by a glass plate of a double chamber, a “standard low particle” section and the “molecular cleanliness” upper level.