Method for manufacturing wiring substrate and wiring substrate manufactured thereby

Abstract

Disclosed herein is a method for fabricating a wiring board in which a target substrate having via holes and/or trenches is subjected to an electroless plating process while being immersed in an electroless plating solution to fill the via holes and/or the trenches with a plating metal. The method includes the steps of: supplying the electroless plating solution to under the target substrate; diffusing an oxygen-containing gas into the electroless plating solution supplied under the target substrate; and allowing the electroless plating solution to overflow from over the target substrate.

1 . A method for fabricating a wiring board in which a target substrate having via holes and/or trenches is subjected to an electroless plating process while being immersed in an electroless plating solution to fill the via holes and/or the trenches with a plating metal, the method comprising the steps of:
 supplying the electroless plating solution to under the target substrate;   diffusing an oxygen-containing gas into the electroless plating solution supplied under the target substrate; and   allowing the electroless plating solution to overflow from over the target substrate, wherein   the electroless plating solution includes at least a water-soluble metal salt, a reducing agent, and a complexing agent, and also includes a leveler comprised of at least one sulfur-containing organic compound represented by any one of the following general Formulae (I)-(V):
   R 1 —(S) n —R 2   (I)
 
   R 1 -L 1 -(S) n —R 2   (II)
 
   R 1 -L 1 -(S) n -L 2 -R 2   (III)
 
   R 1 —(S) n -L 3   (IV)
 
   R 1 -L 1 -(S) n -L 3   (V)
 
   where n is an integer equal to or greater than one; R 1  and R 2  independently represent an aliphatic or aromatic cyclic group including any arbitrary number of carbon atoms, oxygen atoms, phosphorus atoms, sulfur atoms, or nitrogen atoms, or a cyclic group in which one or more arbitrary substituents are bonded to the aliphatic or aromatic cyclic group;
 L 1  and L 2  independently represent a linear or branched one of a chain selected from the group consisting of an alkyl chain, an alkyl amino chain, an alkylene chain, and an alkoxy chain, and 
 L 3  is selected from the group consisting of an alkyl group, an alkylene group, an amino group, an alkyl amino group, an alkylene amino group, a hydroxyl group, an alkyl hydroxyl group, an alkylene hydroxyl group, a carboxyl group, an alkyl carboxyl group, an alkylene carboxyl group, an alkyl amino carboxyl group, an alkylene amino carboxyl group, a nitro group, an alkyl nitro group, a nitrile group, an alkyl nitrile group, an amide group, an alkyl amide group, a carbonyl group, an alkyl carbonyl group, a sulfonic group, an alkyl sulfonic group, a phosphonic group, an alkyl phosphonic group, a sulfanyl group, a sulfinyl group, and a thiocarbonyl group. 
   
     
     
         2 . The method of  claim 1 , wherein
 the oxygen-containing gas has an air bubble size of 5 μm to 50 μm.   
     
     
         3 . The method of  claim 1 , comprising
 the step of diffusing no oxygen-containing gas for a predetermined amount of time before starting the electroless plating process.   
     
     
         4 . The method of  claim 1 , wherein
 the electroless plating process is performed by an electroless plating system comprising: a plating tank filled with the electroless plating solution; a plating solution supply means for supplying the electroless plating solution to under the target substrate; a diffusion means for diffusing an oxygen-containing gas into the electroless plating solution; and an overflow tank allowing the electroless plating solution to overflow from over the target substrate.   
     
     
         5 . The method of  claim 4 , wherein
 the diffusion means is made of a porous ceramic material.   
     
     
         6 . The method of  claim 4 , wherein
 the electroless plating system includes a rectifier means for rectifying a flow of the electroless plating solution in the plating tank.   
     
     
         7 . A wiring board fabricated by the method of  claim 1 .