Surface processing apparatus

Abstract

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.

What is claimed is:  
     
         1 . A surface processing apparatus provided with a reactor in which plasma is generated and an object whose surface is to be processed by said plasma is arranged and a magnet plate for creating a point-cusp magnetic field distributed in a space within said reactor, in which said plasma is generated, wherein 
 said magnet plate is provided with a plurality of magnets arranged in a circular plane, facing in parallel a surface of said object, one magnetic pole end face of each of the plurality of magnets is arranged at a position of each of the lattice points forming hexagonal shapes on said circular plane, and the polarities of said magnetic pole end faces of two adjoining magnets are arranged to become opposite.    
     
     
         2 . A surface processing apparatus as set forth in  claim 1 , wherein said hexagonal shape is a regular hexagonal shape.  
     
     
         3 . A surface processing apparatus as set forth in  claim 1 , wherein said hexagonal shape has three pairs of parallel facing sides and different lengths of each pair of sides.  
     
     
         4 . A surface processing apparatus as set forth in  claim 3 , wherein the longest side is not more than two times the shortest side.  
     
     
         5 . A surface processing apparatus as set forth in  claim 1 , wherein at least two magnets are arranged for each of said lattice points of said hexagonal shape.  
     
     
         6 . A surface processing apparatus as set forth in  claim 1 , wherein other magnets of reduced magnetic force are arranged at an outermost region of said circular plane and wherein disturbances in periodicity of unit lattices are corrected.  
     
     
         7 . A surface processing apparatus as set forth in  claim 6 , wherein the lengths of the other magnets are made shorter to reduce the magnetic force.  
     
     
         8 . A surface processing apparatus provided with a reactor in which plasma is generated and an object whose surface is to be processed by said plasma is arranged, and a magnet plate for creating a point-cusp magnetic field distributed in a space within said reactor, in which said plasma is generated, wherein 
 said magnet plate is provided with a plurality of magnets arranged in a circular plane facing in parallel a surface of said object, one magnetic pole end face of each of the plurality of magnets is arranged at a position of each of a plurality of lattice points on said circular plane, the polarities of said magnetic pole end faces of two adjoining magnets are arranged to become opposite, and some of said magnets arranged at an outermost region of said circular plane among said plurality of magnets are reduced in magnetic force.    
     
     
         9 . A surface processing apparatus as set forth in  claim 8 , wherein said lattice points are those forming a square shape.  
     
     
         10 . A surface processing apparatus as set forth in  claim 8 , wherein the length of some of said magnets arranged at said outermost region is shortened.  
     
     
         11 . A surface processing apparatus as set forth in  claim 10 , wherein said short length magnets are attached so that their magnetic pole end faces are positioned at the same heights as the magnetic pole end faces of other said magnets.  
     
     
         12 . A surface processing apparatus as set forth in  claim 8 , wherein at least two magnets are arranged at positions of each of said lattice points.