Apparatus for plating small-sized plating-piece

Abstract

An apparatus for plating small-sized plating-pieces has a cathode and a plurality of grooves are formed on the surface of the cathode which is to come into contact with small-sized plating-pieces, so that an electric field can be concentrated onto the vicinities of the grooves. Thus, the electric field can be sufficiently dispersed on the whole cathode.

What is claimed is:  
     
         1 . An apparatus for plating a plurality of small-sized plating-pieces comprising: 
 a plating bath in which a plating solution is provided; and    a cathode and an,anode made of conductors, which are dipped into the plating solution, respectively, the cathode having at least one concavity formed on a surface thereof which is to contact with the small-sized plating-pieces;    wherein a plurality of the small-sized plating-pieces are caused to contact with the cathode in the plating solution, and conduction is carried out between the cathode and the anode, so that plating films are deposited onto the small-sized plating-pieces.    
     
     
         2 . An apparatus for plating small-sized plating-pieces according to  claim 1 , wherein the at least one concavity includes a plurality of grooves formed on the surface of the cathode.  
     
     
         3 . An apparatus for plating small-sized plating-pieces according to  claim 2 , wherein the plurality of grooves are arranged so as to intersect each other.  
     
     
         4 . An apparatus for plating small-sized plating-pieces according to  claim 1 , wherein the at least one concavity includes a plurality of small holes formed on the surface of the cathode.  
     
     
         5 . An apparatus for plating small-sized plating-pieces according to  claim 1 , wherein the concavity includes a chamfer portion formed on the circumferential edge of the surface of the cathode.  
     
     
         6 . An apparatus for plating small-sized plating-pieces according to  claim 1 , further comprising a container which contains a plurality of the small-sized plating-pieces in the plating solution, and the cathode is arranged so as to define a portion of the bottom of the container.  
     
     
         7 . An apparatus for plating small-sized plating-pieces according to  claim 6 , wherein the container is rotatable about a vertical axis of the container.  
     
     
         8 . An apparatus for plating small-sized plating-pieces according to  claim 1 , wherein the small-sized plating pieces include small-sized electronic components.  
     
     
         9 . An apparatus for plating small-sized plating-pieces according to  claim 7 , further comprising a shaft, wherein the container is rotatable about the shaft and four electrodes are arranged at intervals of about 90° around the shaft.  
     
     
         10 . An apparatus for plating small-sized plating-pieces according to  claim 2 , wherein widths of the grooves are smaller than the sizes of the small-sized electronic components.  
     
     
         11 . An apparatus for plating small-sized plating-pieces according to  claim 2 , wherein each of the grooves has one of a substantially V-shaped cross-section, a substantially U-shaped configuration, and a substantially quadrangular-shaped configuration.  
     
     
         12 . An apparatus for plating small-sized plating-pieces according to  claim 4 , wherein diameters of the holes are smaller than the sizes of the small-sized electronic components.  
     
     
         13 . An apparatus for plating small-sized plating-pieces according to  claim 4 , wherein each of the holes has one of a substantially V-shaped cross-section, a substantially U-shaped configuration, and a substantially quadrangular-shaped configuration.  
     
     
         14 . A method of plating a plurality of small-sized plating-pieces comprising the steps of: 
 providing a plating bath in which a plating solution is provided;    providing a cathode and an anode made of conductors, the cathode having at least one concavity formed on a surface thereof which is to contact with the small-sized plating-pieces;    dipping the cathode and the anode into the plating bath so as that a plurality of the small-sized plating-pieces are caused to contact with the cathode in the plating solution, and conduction is carried out between the cathode and the anode, so that plating films are deposited onto the small-sized plating-pieces.    
     
     
         15 . The method according to  claim 14 , wherein the at least one concavity includes a plurality of grooves formed on the surface of the cathode.  
     
     
         16 . The method according to  claim 15 , wherein the plurality of grooves are arranged so as to intersect each other.  
     
     
         17 . The method according to  claim 14 , wherein the at least one concavity includes a plurality of small holes formed on the surface of the cathode.  
     
     
         18 . The method according to  claim 14 , wherein the concavity includes a chamfer portion formed on the circumferential edge of the surface of the cathode.  
     
     
         19 . The method according to  claim 1 , further comprising the step of rotating the container about a vertical axis of the container during depositing of the plating films onto the small-sized plating pieces.  
     
     
         20 . The method according to  claim 15 , wherein widths of the grooves are smaller than the sizes of the small-sized electronic components.  
     
     
         21 . The method according to  claim 15 , wherein each of the grooves has one of a substantially V-shaped cross-section, a substantially U-shaped configuration, and a substantially quadrangular-shaped configuration.  
     
     
         22 . The method according to  claim 17 , wherein diameters of the holes are smaller than the sizes of the small-sized electronic components.  
     
     
         23 . The method according to  claim 17 , wherein each of the holes has one of a substantially V-shaped cross-section, a substantially U-shaped configuration, and a substantially quadrangular-shaped configuration.