Sputtering target and method for the manufacture thereof

Abstract

A sputtering target is provided which provides early stabilization of the film-deposition rate of the sputtering target from its initial stage of use. The sputtering target surface subjected to erosion is formed with a surface-deformed layer. The surface-deformed layer is reduced by precision machining and removed by etching. The extent of etching is controlled so that the surface roughness (Ra) is in a range between 0.1% and 10% of the mean crystal grain diameter of the material constituting the target. The surface roughness (Ra) is defined as the mean roughness on the center line of the surface.

We claim:  
     
         1 . A sputtering target comprising a surface subjected to erosion, said surface being substantially free of a surface-deformed layer, made of a material having a predetermined mean crystal grain diameter, and having a surface roughness (Ra) defined by a mean roughness on a center line of said surface in a range of between about 0.1% and 10% of said mean crystal grain diameter of said material.  
     
     
         2 . A sputtering target according to    claim 1   , wherein said surface roughness (Ra) is in a range between 1% and 10% of said mean crystal grain diameter of said material.  
     
     
         3 . A method for manufacturing a sputtering target which has a surface subjected to erosion, the surface having a surface-deformed layer and being made of a material having a pre-determined mean crystal grain diameter, comprising the steps of: 
 precision machining the surface of the sputtering target to reduce the surface-deformed layer; and    etching the surface to provide the surface with a surface roughness (Ra) in a range of between about 0.1% and 10% of the mean crystal grain diameter of the material, said surface roughness (Ra) being defined as a mean roughness on a center line of the surface.    
     
     
         4 . A method of manufacturing a sputtering target according to    claim 3   , wherein said surface roughness (Ra) is in a range of between 1% and 10% of the mean crystal grain diameter of the material.  
     
     
         5 . A method of manufacturing a sputtering target according to    claim 3   , wherein the surface-deformed layer has a thickness, and wherein said thickness of the surface-deformed layer is reduced to 20 μm or less during said precision machining step.  
     
     
         6 . A method of manufacturing a sputtering target according to    claim 4   , wherein the surface-deformed layer has a thickness, and wherein said thickness of the surface-deformed layer is reduced to 20 μm or less during said precision machining step.