Plating apparatus

Abstract

A plating apparatus includes a plating bath in which a plating solution including plating targets is stored and an injector that is in the plating bath and that injects the plating solution. The plating targets included in the plating solution are stirred by the plating solution injected from the injector. The injector has an inner cylindrical shape including a bottom surface extending in a horizontal direction, an inner wall extending in a height direction from the bottom surface, and an opening defined in an upper end of the inner wall. The opening is a first injection port that injects the plating solution to the plating bath. A mesh portion is provided at the first injection port. A second injection port that injects the plating solution to the injector is provided in the bottom surface.

What is claimed is: 
     
         1 . A plating apparatus comprising:
 a plating bath in which a plating solution including plating targets is stored; and   an injector that is provided in the plating bath and that injects the plating solution; wherein   the plating targets included in the plating solution are stirred by the plating solution injected from the injector;   the injector has an inner cylindrical shape including a bottom surface extending in a horizontal direction, an inner wall extending in a height direction from the bottom surface, and an opening defined in an upper end of the inner wall;   the opening is a first injection port that injects the plating solution to the plating bath;   a mesh portion is provided at the first injection port;   a second injection port that injects the plating solution to the injector is provided in the bottom surface;   a flow velocity control plate in which a plurality of holes are defined is provided at a point in the height direction of the injector, the flow velocity control plate being in parallel with the bottom surface;   the flow velocity control plate includes a central portion and a circumferential portion provided outside the central portion when viewed in a planar direction;   the plurality of holes are defined in each of the central portion and the circumferential portion; and   a cylindrical portion including a hollow portion is provided between the flow velocity control plate and the mesh portion at the first injection port.   
     
     
         2 . The plating apparatus according to  claim 1 , wherein an opening area of each of the holes defined in the central portion is smaller than an opening area of each of the holes defined in the circumferential portion. 
     
     
         3 . The plating apparatus according to  claim 2 , wherein a total opening area of the plurality of holes per unit area defined in the central portion is identical to or smaller than a total opening area of the plurality of holes per unit area defined in the circumferential portion. 
     
     
         4 . The plating apparatus according to  claim 1 , wherein an opening area of each of the holes defined in the central portion is identical to an opening area of each of the holes defined in the circumferential portion, but a number of the holes per unit area defined in the central portion is smaller than a number of the holes per unit area defined in the circumferential portion. 
     
     
         5 . The plating apparatus according to  claim 1 , wherein a total opening area of the plurality of holes per unit area defined in the central portion is smaller than a total opening area of the plurality of holes per unit area defined in the circumferential portion. 
     
     
         6 . The plating apparatus according to  claim 1 , wherein when the flow velocity control plate and the cylindrical portion are viewed in the planar direction:
 the central portion of the flow velocity control plate is located inside the cylindrical portion; and   the circumferential portion of the flow velocity control plate is located outside the cylindrical portion.   
     
     
         7 . The plating apparatus according to  claim 1 , wherein when the flow velocity control plate is viewed in the planar direction, the holes defined in the central portion and the holes defined in the circumferential portion each have a circular shape. 
     
     
         8 . The plating apparatus according to  claim 1 , wherein
 the mesh portion includes a mesh central portion and a mesh circumferential portion provided outside the mesh central portion when viewed in the planar direction; and   a mesh opening of the mesh central portion is smaller than a mesh opening of the mesh circumferential portion.   
     
     
         9 . The plating apparatus according to  claim 8 , wherein
 the mesh portion in the mesh circumferential portion is made of one layer of mesh; and   the mesh portion in the mesh central portion is formed of a plurality of layers of mesh.   
     
     
         10 . The plating apparatus according to  claim 1 , wherein a metal pipe having a cylindrical shape and including a hollow portion is provided directly above the injector. 
     
     
         11 . The plating apparatus according to  claim 10 , further comprising:
 a partition wall pipe made of an electrically insulating material, the partition wall pipe having a cylindrical shape and including a hollow portion, the partition wall pipe being provided with a plurality of holes through which the plating solution passes but through which the plating targets do not pass; and   a second electrode; wherein   the metal pipe serves as a first electrode;   the metal pipe, the partition wall pipe, and the second electrode are each accommodated in the plating bath;   the metal pipe is located inside the hollow portion of the partition wall pipe, and a plating forming portion is provided between an inside of the partition wall pipe and an outside of the metal pipe;   the second electrode is located outside the partition wall pipe;   the injector is provided below the metal pipe;   the plating targets are moved upward through the hollow portion of the metal pipe with an upward flow of the plating solution injected from the injector;   the plating targets are discharged to an outside of the hollow portion of the metal pipe from an upper end of the hollow portion of the metal pipe and stirred in the plating solution;   the plating targets subsequently fall downward through the plating forming portion; and   while the plating targets fall downward, the plating targets each are plated by application of a current between the metal pipe defining and functioning as the first electrode and the second electrode.   
     
     
         12 . The plating apparatus according to  claim 11 , wherein
 the first electrode is a cathode electrode; and   the second electrode is an anode electrode.   
     
     
         13 . The plating apparatus according to  claim 10 , wherein two rod-shaped electrically-conductive support portions are integrally provided with an upper portion of the metal pipe. 
     
     
         14 . The plating apparatus according to  claim 10 , wherein the second electrode has a cylindrical shape. 
     
     
         15 . The plating apparatus according to  claim 10 , wherein the metal pipe, the partition wall pipe, and second electrode are arranged concentrically with aligned central axes. 
     
     
         16 . The plating apparatus according to  claim 1 , further comprising a circulation line connected between a liquid suction port located in the plating bath and the second injection port.