Multilayer-film reflective mirrors, extreme UV microlithography apparatus comprising same, and microelectronic-device manufacturing methods utilizing same

摘要

Microlithography apparatus and methods are disclosed for achieving high-resolution pattern transfer of a pattern onto a substrate, such as a semiconductor wafer, using extreme ultraviolet (EUV, also termed soft X-ray) radiation. The apparatus include an imaging-optical system (projection-optical system) capable of receiving pattern-encoding EUV light from a mask and forming an image of the pattern on the substrate. The desired wavelength of the EUV light is 20 nm to 50 nm, and the imaging-optical system includes multiple reflective mirrors having aspherical surficial profiles and multilayer-film reflective surfaces. The apparatus are configured especially to achieve a pattern-element resolution, of the projected image, of 70 nm or finer.