Through electrode and method for forming the same

Abstract

A method for forming a through electrode is disclosed. The through electrode integrally comprises a columnar electrode filling a through hole, a lower end electrode pad formed on a lower end side of a columnar electrode and having an area wider than the cross section of the through hole, and an upper end electrode pad formed on an upper end side of the columnar electrode and having an area wider than the cross section of the through hole. The lower end electrode pad is arranged is arranged to occlude a lower end opening of the through hole. The columnar electrode fills the through hole by laminating copper on the lower end electrode pad.

1 . A method for forming a through electrode, comprising: 
 a first step of forming a seed layer on a surface of a support body;    a second step of forming an adhesive layer on a surface of the seed layer;    a third step of pressing a substrate having a through hole formed therein onto the adhesive layer;    a fourth step of removing a portion of the adhesive layer that communicates with the through hole of the substrate to form a clearance wider than a cross section of the through hole at a lower end of the through hole;    a fifth step of filling the clearance and the through hole with a conductor to form a lower end electrode pad covering the lower end of the through hole and a columnar electrode filling the through hole; and    a sixth step of removing the support body, the seed layer, and the adhesive layer from the substrate.    
   
   
       2 . The method for forming a through electrode as claimed in  claim 1 , wherein the fifth step includes: 
 a step of forming an Au layer constituting the lower end electrode pad on the surface of the seed layer;    a step of forming a Ni layer on a surface of the Au layer; and    a step of laminating a Cu layer on a surface of the Ni layer to form the columnar electrode.    
   
   
       3 . The method for forming a through electrode as claimed in  claim 1 , 
 wherein an adhesive tape is applied to the surface of the support body, and then the seed layer is formed on an adhesive face of the adhesive layer in the first step; and    after the columnar electrode is formed in the fifth step, the support body is separated from the seed layer by heating the adhesive tape in the sixth step.    
   
   
       4 . The method for forming a through electrode as claimed in  claim 1 , 
 wherein the seed layer is formed on the surface of the support body in the first step, and then the adhesive layer is formed on the seed layer; and    after the columnar electrode is formed inside the through hole in the fifth step, the support body is separated from the seed layer by heating the adhesive layer in the sixth step.    
   
   
       5 . The method for forming a through electrode as claimed in  claim 1 , 
 wherein the adhesive layer includes a photoresist layer; and    the fourth step includes    a step of removing the photoresist layer formed in the area communicating with the through hole of the substrate by a development process; and    a step of forming the clearance wider than the cross section of the through hole at the lower end of the through hole.    
   
   
       6 . The method for forming a through electrode as claimed in  claim 1 , further comprising: 
 a step of laminating a resist layer on an upper face of the substrate and forming an opening wider than the cross section of the through hole at an upper end of the through hole in the resist layer;    a step of filling the opening of the resist layer with a conductor to form an upper end electrode pad continuous to an upper end of the columnar electrode; and    a step of removing the resist layer surrounding the upper end electrode pad.    
   
   
       7 . An electrode that is inserted in a through hole extending through a substrate and electrically connects a conductor pattern formed on an upper face of the substrate to a conductor pattern formed on a lower face of the substrate, comprising: 
 a lower end electrode pad wider than a cross section of the through hole and configured to seal a lower end opening of the through hole; and    a columnar electrode formed from bottom to top so as to fill the through hole by laminating a conductive material on the lower end electrode pad.    
   
   
       8 . The through electrode as claimed in  claim 7 , wherein an upper end electrode pad wider than the cross section of the through hole and configured to seal an upper end opening of the through hole is formed on an upper end of the columnar electrode.