Method and apparatus for sputter deposition of target material to a substrate

An apparatus for sputter deposition of target material to a substrate, the apparatus comprising:

• a substrate guide arranged to guide a substrate along a curved path, wherein the substrate is in a form of a web;
• a target portion spaced from the substrate guide and arranged to support target material, the target portion and the substrate guide defining between them a deposition zone;
• and
• a confining arrangement comprising one or more magnetic elements arranged to provide a confining magnetic field to confine plasma in the deposition zone thereby to provide for sputter deposition of target material to the web of substrate in use, the confining magnetic field including magnetic field lines arranged to, at least in the deposition zone, substantially follow a curve of the curved path so as to confine said plasma around said curve of the curved path, wherein each of the one or more magnetic elements is in a form of a solenoid, the solenoid being elongate in a direction substantially perpendicular to a direction of the magnetic field lines of the confining magnetic field in use.