THIN-FILM PROCESSING ELECTROMAGNET FOR LOW-SKEW MAGNETIC ORIENTATION

摘要

An electromagnet having one or more coils wrapped around a plate-shaped core produces a uniaxial magnetic field in the vicinity of a substrate surface for orienting a magnetic film deposited onto the substrate surface. Variations in the magnetic mass of the plate-shaped core of in the magnetic permeability of the core mass are made to reduce angular skew and to improve uniformity of the uniaxial magnetic field. The variations generally involve a reduction in magnetic mass or permeability near a center (64) of the core with respect to a periphery of the core (56). Cavities of various sizes and shapes but having symmetry with a magnetic axis can be formed in the core for this purpose. Recesses (60, 62), coolant passages (70), plugs (72), diagonal passages (74), front surface (52), and notches (58) are present.