Patent ID: 8048277

Claim:
A magnet unit for a magnetron sputtering apparatus comprising on the back side of a cathode electrode which supports a rectangular target: a yoke formed of a ferromagnetic plate material, a peripheral magnet disposed on the yoke so as to follow the outline of the target, and an inner magnet disposed inside the peripheral magnet on the yoke and having a polarity different from the polarity of the peripheral magnet, wherein the magnet unit forms a magnetic track as a set of regions which a tangent of a magnetic field line generated on the target by the peripheral magnet and the inner magnet parallels to a surface of the target, the magnet unit comprising: n (n is a positive integer of two or more) extending magnetic pole portions extending from the central portion of the inner magnet toward the both sides in its longitudinal direction and adjacent to the both ends in the longitudinal direction of the peripheral magnet; and n−1 projecting magnetic pole portions protruding inward in the longitudinal direction of the peripheral magnet from the inside of both ends of the peripheral magnet and located between the n extending magnetic pole portions, wherein the inner magnet comprises n magnetic pole long pieces, which have the extending magnetic pole portion at the both ends, pass through the central portion in the longitudinal direction of the peripheral magnet, and are disposed in parallel along the longitudinal direction, and binding magnetic pole piece connecting the n magnetic pole long pieces, and the n magnetic pole long pieces and the binding magnetic pole piece have the same polarity, and wherein the n extending magnetic pole portions and the n−1 projecting magnetic pole portions form 2n−1 folded shape portions at the both ends in the longitudinal direction of the magnetic track.