Patent Number: 
Section: claims

1. A method for flattening a surface of a solid by irradiating the surface of the solid with a gas cluster ion beam, comprising:a step of supporting a solid composed of different materials of different etching rates and having a surface to be flattened including areas of the different etching rates of the different materials;a step of generating a gas cluster ion beam with an average cluster size of 50 or larger; anda step of irradiating the surface of the solid including the areas of the different etching rates with the gas cluster ion beam at an irradiation angle smaller than 30° between the surface of the solid and the gas cluster ion beam. 2. The solid surface flattening method according to claim 1, wherein the solid is a composite of particles of the different materials with an average grain size being less than 1 μm, but not less than 100 nm or a multilayer film of plural layers of the different materials with an average film thickness of each layer being less than 1 μm, but not less than 100 nm; and the irradiation angle is 25° or less. 3. The solid surface flattening method according to claim 1, wherein the solid is a composite of different types of particle forming the different materials with an average grain size being equal to or larger than 1 μm or a multilayer film of plural layers forming the different materials with an average film thickness of each layer being equal to or larger than 1 μm; and the irradiation angle is 20° or less. 4. A solid surface flattening apparatus which flattens a surface of a solid sample through irradiation with a gas cluster ion beam, comprising:means for generating the gas cluster ion beam;cluster size sorting means for selecting a cluster size equal to or larger than 50 for the gas cluster ion beam;sample supporting means for supporting a solid composed of different materials of different etching rates and having a surface including areas of the different etching rates of the different materials in such a way as to be able to vary an incident angle of the gas cluster ion beam whose cluster size has been selected;irradiation angle setting means for setting an irradiation angle between the surface of the solid sample and the gas cluster ion beam to less than 30°; andmeans for irradiating the surface of the solid including the areas of the different etching rates with the gas cluster ion beam at an irradiation angle set less than 30° by the irradiation angle setting means.