Method of smoothing solid surface with gas cluster ion beam and solid surface smoothing apparatus

Abstract

A scratch or similar surface roughness in a solid surface is reduced by gas cluster ion beam irradiation. A gas-cluster-ion-beam solid surface smoothing method includes an irradiation step in which the solid surface is irradiated with a gas cluster ion beam. The irradiation step includes a process of causing clusters from a plurality of directions to collide with at least an area (spot) irradiated with the gas cluster ion beam in the solid surface. Collision of clusters from a plurality of directions with the spot can be brought about by emitting a divergent gas cluster ion beam which releases clusters in diverging directions with respect to the beam center, for example.

What is claimed is: 
     
         1 . A method of smoothing a solid surface with a gas cluster ion beam, the method comprising:
 irradiating the solid surface with said gas cluster ion beam; and   irradiating the solid surface with one or more additional gas cluster ion beams simultaneously with irradiation of said gas cluster ion beam so as to expose substances in the solid surface transferred laterally by collisions with gas clusters to other gas clusters, each axis of said one or more additional gas cluster ion beams not being parallel to an axis of said gas cluster ion beam.   
     
     
         2 . A method of smoothing a solid surface with a gas cluster ion beam that comprises irradiating the solid surface with the gas cluster ion beam,
 wherein the irradiating comprises, when scratches which can be likened to a line-and-space pattern structure with widths and heights on the order of a submicrometer to micrometer are present on the solid surface, a process of emitting the gas cluster ion beam so as to expose substances, which remain on side-walls of the scratches due to lateral transferal caused by collisions with gas clusters, to other gas clusters,   and wherein the gas cluster ion beam diverges non-concentrically and/or non-uniformly.   
     
     
         3 . The method according to  claim 2 , wherein:
 the solid is moved back and forth in each of two directions which are normal to each other;   the solid is moved back and forth at a rate of over 1 Hz in one direction of said two directions; and   the solid is moved back and forth at a rate of over 0.02 Hz in another direction of said two directions.   
     
     
         4 . The method according to  claim 2 , wherein:
 the solid is rotated at a rate of over 60 revolutions per minute, and   irradiation of the gas cluster ion beam is performed by emitting the gas cluster ion beam with an irradiation angle between the gas cluster ion beam and a normal to the solid surface irradiated with the gas cluster ion beam being not equal to 0°.   
     
     
         5 . A solid surface smoothing apparatus for smoothing a solid surface with a gas cluster ion beam, comprising:
 a plurality of gas cluster ion beam emitters, each emitter having an irradiation axis and emitting a respective gas cluster ion beam along its irradiation axis onto the solid surface,   wherein irradiation axes of the plurality of the gas cluster ion beam emitters are not parallel to each other so as to expose substances in the solid surface transferred laterally by collisions with gas clusters to collisions with other gas clusters so that the substances do not remain on the solid surface.