PURPOSE: To form a soft magnetic layer having low coercive force and high magnetic permeability in the stage of forming the soft magnetic material by executing sputtering on the upper stream of the moving direction of a substrate while maintaining the forming layer at the potential lower than the plasma potential on the down stream thereof.
CONSTITUTION: One end of the thin 'Permalloy(R)' film MM continuously formed by sputtering on the film substrate BD' which moves under taking up contacts with a take-up guide roller 6 which is kept biased to the potential lower than the potential of an anode electrode 8. Therefore the film MM self-biases the surface of the substrate BD' to the potential lower than the plasma potential by the conductivity of the film MM itself after the above-mentioned contact. The film MM to be formed thereafter by sputtering is thus the soft magnetic layer having the excellent soft magnetic characteristics such as low coercive force (low Hc) and high magnetic permeability (high μ).
SUGINO SO
SUMIYA KAZUHIKO
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