To develop multilayer mirrors for use at wavelengths shorter than 12.4 nm in soft X-ray projection lithography, Ni/C multilayers were fabricated using r.f. sputtering. Evaluation of their layered structure and reflectivity showed that multilayers deposited at about 80 degrees C had substantial interface roughness, while those deposited at about -20 degrees C had well-formed layers with a periodic length of about 5.5 nm and an interface roughness of 0.25 nm. A fabricated Ni/C multilayer with 35 pairs of 2.3 nm Ni and 3.2 nm C layers showed a high measured reflectivity of 18% at a wavelength of about 7 nm.