One type of radiation used in semiconductor photolithography is extreme ultraviolet (EUV) radiation. EUV light can be produced by creating a small, hot plasma, which efficiently radiates at a desired wavelength, for example 13.4 nm. The plasma is created in a vacuum chamber, typically by driving a pulsed electrical discharge through a fuel material, or by focusing a pulsed laser beam onto a fuel material. The light produced by the plasma is then collected by nearby mirrors and sent downstream to the rest of the lithography tool.
Debris and gases may be released by this plasma, either directly from the fuel material used, or indirectly from the erosion of nearby materials. The debris and gases may travel downstream the lithography tool and damage sensitive mirrors and other optical components. In addition, the type of fuel used may cause damage. Foil traps, gas curtains, baffling, and shielding are typically used to partially block the debris while allowing an open path for the EUV light to pass through.
USPTO Backgrounds
USPTO Backgrounds