To prepare a film extremely small in surface roughness by executing the discharge of a cathode by using a mechanism in which the vicinity of the cathode is provided with a coil for rf inductive coupling discharge for supporting magnetron discharge under a low discharge pressure.
As the main operations of an rf inductive coil, the promotion of the ionization of sputtering particles and a sputtering gas and the control of the plasma potential between the coil and a substrate are cited. The sputtering particles having a high ionization rate are made incident on the substrate at relatively high kinetic energy, by which the densification and flattening of the film can be attained. The discharge electric powder for the rf inductive coil is preferably regulated to 20 to 65 W. Moreover, in the case a reactive sputtering method is used, it is preferable that the partial pressure of a reaction gas is regulated to 5×10-3 to 1×10-2 Pa, and the ion energy of the sputtering particles ionized by rf inductive coupling discharge is regulated to 1.2 to 40 eV.
YAMAMOTO NAOSHI
MATSUURA MASAMICHI
