Electroplating method

Abstract

An electroplating method is capable of reliably embedding via holes with a plated metal such as copper or the like when a substrate with a seed layer of a metal having a greater ionization tendency than hydrogen is electroplated using an acidic plating solution such as a copper sulfate plating solution. The electroplating method including preparing a substrate having via holes covered with a first metal, which has a greater ionization tendency than hydrogen, in a surface thereof, pretreating the substrate by immersing the substrate in a pretreatment solution in which a second metal that is more noble than the first metal or a salt thereof is dissolved, and then electroplating the surface of the substrate to embed the second metal or a third metal in the via holes.

1 . An electroplating method comprising:
 preparing a substrate having via holes covered with a first metal, which has a greater ionization tendency than hydrogen, in a surface thereof;   pretreating the substrate by immersing the substrate in a pretreatment solution in which a second metal that is more noble than the first metal or a salt thereof is dissolved;   and then electroplating the surface of the substrate to embed the second metal or a third metal in the via holes.   
     
     
         2 . An electroplating method according to  claim 1 , wherein the pretreatment solution is in the range from a mildly acidic level to a mildly alkaline level. 
     
     
         3 . An electroplating method according to  claim 1 , further comprising:
 pretreating the substrate by immersing the substrate in deaerated water before pretreating the substrate by immersing the substrate in the pretreatment solution in which the second metal or the salt thereof is dissolved.   
     
     
         4 . An electroplating method according to  claim 1 , wherein the first metal is cobalt. 
     
     
         5 . An electroplating method according to  claim 1 , wherein the second metal is copper, and the pretreatment solution has a copper concentration ranging from 1 to 70 g/L. 
     
     
         6 . An electroplating method according to  claim 1 , wherein the second metal is palladium, cold, platinum, or silver, and the third metal is copper. 
     
     
         7 . An electroplating method according to  claim 4 , wherein the second metal is copper, and the pretreatment solution has a copper concentration ranging from 1 to 70 g/L. 
     
     
         8 . An electroplating method according to  claim 4 , wherein the second metal is palladium, cold, platinum, or silver, and the third metal is copper.