FORMATION OF THIN MAGNETIC FILM

PURPOSE:To form a thin magnetic film having a uniform thickness free from applying unevenness, when magnetic paint is applied to the surface of a substrate being rotated, by locating an over plate having a specified shape above the substrate. CONSTITUTION:A substrate 3 is attached to a spindle 4 arranged inside a chamber 5, and magnetic paint is applied to the surface of the substrate 3 being slowly rotated at a speed of 50-250rpm. Thereafter, the rotation speed is raised to 1,000rpm or so to shake off the adherent paint by a centrifugal force. Thus, a thin magnetic film is formed. In this case, an over plate 2', having a shape such that a distance from the substrate 3 becomes longer from the peripheral side to the inner side, is located above the rotating substrate 3. The over plate 2' comes near the substrate 3 at a space outside the substrate 3, so that the vapor pressure of a solvent in the paint is likely to be saturated and that evaporation of the solvent is suppressed. Consequently, increase in viscosity of the paint is slower at the outer space than that at the inner space, and the rate of the paint to be shaked off by the centrifugal force is larger at the outer space than that at the inner space. Thus, a difference in thickness between the outer part and the inner part of the paint film is reduced, and the magnetic film having a uniform thickness can be formed.