Microstructures and method of manufacture

Abstract

In order to provide a structure which has a sufficiently large signal strength and generates local plasmon resonance of excellent reproducibility, the invention provides a process for manufacturing a structure at least a portion of which is an aluminum member having on a surface thereof an anodized layer having a plurality of micropores, the process comprising the steps of, in order, anodizing a surface of an aluminum member so as to form an anodized layer having micropores present therein, sealing the micropores in the anodized layer by filling the micropores with metal, surface-treating the sealed anodized layer so as to remove at least a portion of upper layer surface thereof and set the average surface roughness (R a ) to at most 30 nm, and subjecting the surface-treated anodized layer to electrodeposition so as to form metal particles on the metal filled into the micropores during sealing.

1 . A process for manufacturing a structure at least a portion of which is an aluminum member having on a surface thereof an anodized layer having a plurality of micropores, the process comprising the steps of, in order: 
 (a) anodizing a surface of an aluminum member so as to form an anodized layer having micropores present therein;    (b) sealing the micropores in the anodized layer by filling the micropores with metal;    (c) surface-treating the sealed anodized layer so as to remove at least a portion of upper layer surface thereof and set the average surface roughness (R a ) to at most 30 nm; and    (d) subjecting the surface-treated anodized layer to electrodeposition so as to form metal particles on the metal filled into the micropores during sealing.    
     
     
         2 . The process of  claim 1 , wherein 20 to 80% of the anodized layer thickness is removed in the surface treatment step (c).  
     
     
         3 . The process of  claim 1 , wherein the surface treatment step (c) is carried out by at least one method selected from the group consisting of mechanical polishing, chemical dissolution, and ion beam delayering in a vacuum.  
     
     
         4 . The process of  claim 3 , wherein the mechanical polishing method is chemical mechanical polishing.  
     
     
         5 . A structure obtained by the process of  claim 1 , wherein the micropores present in the anodized layer have an average diameter of 10 to 500 nm and a coefficient of variation in diameter of 5 to 20%, and the metal particles formed by electrodeposition have an average diameter larger than the average pore diameter yet smaller than an average center-to-center spacing between neighboring micropores.  
     
     
         6 . A structure obtained by the process of  claim 2 , wherein the micropores present in the anodized layer have an average diameter of 10 to 500 nm and a coefficient of variation in diameter of 5 to 20%, and the metal particles formed by electrodeposition have an average diameter larger than the average pore diameter yet smaller than the average center-to-center spacing between neighboring micropores.  
     
     
         7 . A structure obtained by the process of  claim 3 , wherein the micropores present in the anodized layer have an average diameter of 10 to 500 nm and a coefficient of variation in diameter of 5 to 20%, and the metal particles formed by electrodeposition have an average diameter larger than the average pore diameter yet smaller than the average center-to-center spacing between neighboring micropores.  
     
     
         8 . A structure obtained by the process of  claim 4 , wherein the micropores present in the anodized layer have an average diameter of 10 to 500 nm and a coefficient of variation in diameter of 5 to 20%, and the metal particles formed by electrodeposition have an average diameter larger than the average pore diameter yet smaller than the average center-to-center spacing between neighboring micropores.