Sputtering method

摘要

A method for forming a magnetic film by sputtering is disclosed. The sputtering is directed from a position oblique to a processing surface of a substrate 21, wherein a magnetic field is formed along the processing surface of the substrate while the substrate is rotated about a rotary shaft perpendicular to the processing surface. The substrate 21 is located on a substrate holder 22, with a rotatable magnetic field forming device such as magnets 30 or electromagnets (30, figure 10) being associated with the substrate 21. On exposure to the magnetic field, the substrate 21 has a first portion (Nc, figure 2) to which sputtering particles are apt to be attracted, and a second portion (Sc, figure 2) which has a sputtering particle attracting force lower than that of the first portion. When it is determined that the first portion (Nc, figure 2) of the substrate 21 is at a position close to a cathode 41 generating an electric discharge by supply of electric discharge power, the rotation speed of the substrate is set to a first rotation speed. When it is determined that the second portion (Sc, figure 2) of the substrate 21 is at a position close to the cathode 41, the rotation speed of the substrate is set to a second rotation speed, which is lower than the first rotation speed, to allow more material to be deposited on the substrate. The rotation speed may be increased and decreased gradually as the rotation position of the substrate relative to the cathode changes, e.g. by controlling the rotation speed by calculating the rotation speed as a sinusoidal function of a rotation angle of the substrate. The rotary position of the substrate 21 can be determined by a position detecting device 23. The method provides a magnetic film with uniform film thickness.