Surface processing apparatus
This surface processing apparatus has a reactor in which plasma is generated and a substrate whose surface is to be processed by the plasma is arranged, and a magnet plate for creating a point-cusp magnetic field distributed in an inner space of the reactor, in which the plasma is generated. The magnet plate has a plurality of magnets. These magnets are arranged by a honeycomb lattice structure in a circular plane facing in parallel a surface of the substrate. One magnetic pole end face of each of magnets is arranged at a position of each of the lattice points forming hexagonal shapes on the circular plane. The polarities of the magnetic pole end faces of two adjoining magnets are arranged to become opposite alternately. The magnet plate may be provided with a plurality of magnets arranged by a lattice structure forming a square and the magnetic force (coercive force) of some of the magnets arranged at the outermost region is reduced. Thereby, the periodicity of the point-cusp magnetic field in the inside space is maintained as much as possible even at the peripheral edge and the asymmetry of the distribution of the magnetic field at the region where the periodicity is disturbed at the peripheral edge is reduced.
1. A surface processing apparatus comprising:
a reaction container in which plasma is generated and in which an object having a surface to be processed by the plasma is placed; and
a magnet plate, provided in said reaction container, for generating point cusp magnetic fields distributed in space in said reaction chamber in which the plasma is generated,
said magnet plate including a plurality of magnets arranged on a circular surface thereof to be opposed parallel with the surface to be processed,
said magnets having magnetic pole end surfaces at ends remote from said magnetic plate, respectively, disposed at lattice points forming regular hexagonal shapes on the circular surface,
wherein polarities of adjacent magnetic pole end surfaces of said magnets are opposite to each other,
wherein polarities of the magnetic pole end surfaces of said magnets disposed at diagonal lattice points of respective regular hexagonal shapes are opposite to each other, and
wherein adjacent a peripheral portion of said magnet plate, first rows of said magnets having said magnetic pole end surfaces of a first magnetic polarity and second rows of said magnets having said magnetic pole end surfaces of a second magnetic polarity which is opposite to the first magnetic polarity, generally constitute a hexagonal shape as a whole.
2. An apparatus according to claim 1 , wherein a plurality of said magnets having the same magnetic pole end surfaces are provided at each of the lattice points.
3. An apparatus according to claim 1 , wherein said magnets disposed at an outmost area have a length smaller than a length of the magnets disposed in a central area to provide relatively smaller magnetic forces in the outermost area.