Method of manufacturing multilayer printed wiring board

Abstract

A method of manufacturing a multilayer printed wiring board includes forming a first interlaminar resin insulating layer, a first conductor circuit on the first interlaminar resin insulating layer, a second interlaminar resin insulating layer, opening portions in the second interlaminar resin insulating layer to expose a face of the first conductor circuit, an electroless plating film on the second interlaminar resin insulating layer and the exposed face, and a plating resist on the electroless plating film. The method further includes substituting the electroless plating film with a thin film conductor layer, having a lower ion tendency than the electroless plating film, and a metal of the exposed face, forming an electroplating film including the metal on a portion of the electroless plating film and the thin film conductor layer, stripping the plating resist, and removing the electroless plating film exposed by the stripping.

1 . A method of manufacturing a multilayer printed wiring board, comprising:
 forming a first interlaminar resin insulating layer;   forming a first conductor circuit on the first interlaminar resin insulating layer;   forming a second interlaminar resin insulating layer on the first conductor circuit and the first interlaminar resin insulating layer;   forming an opening portion in the second interlaminar resin insulating layer to expose a face of the first conductor circuit;   forming an electroless plating film on a surface of the second interlaminar resin insulating layer and the exposed face of the first conductor circuit;   forming a plating resist on a portion of the electroless plating film;   substituting the electroless plating film formed on the exposed face and the second interlaminar resin, on which the plating resist is not formed, with a thin film conductor layer, the thin film conductor layer having a lower ion tendency than the electroless plating film and including a metal of the exposed face of the first conductor circuit;   forming an electroplating film including the metal on the thin film conductor layer;   stripping the plating resist, and   removing the electroless plating film exposed by the stripping of the plating resist.   
     
     
         2 . The method as set forth in  claim 1 , wherein the substituting comprises substituting a fraction of the electroless plating film on the portion of the electroless plating film, on which the plating resist is not formed, with the thin film conductor layer. 
     
     
         3 . The method as set forth in  claim 1 , wherein
 the electroless plating film includes nickel; and   the electroplating film includes copper.   
     
     
         4 . The method as set forth in  claim 1 , wherein the removing comprises removing the electroless plating film with an etchant. 
     
     
         5 . The method as set forth in  claim 4 , wherein the etchant does not substantially etch the electroplating film. 
     
     
         6 . The method as set forth in  claim 1 , wherein the first interlaminar resin insulating layer includes glass fiber as a core material. 
     
     
         7 . The method as set forth in  claim 1 , further comprising:
 adhering a palladium catalyst to a surface of the second interlaminar resin insulating layer and the exposed face of the first conductor circuit,   wherein the forming the electroless plating film comprises forming the electroless plating film on the palladium catalyst.   
     
     
         8 . The method as set forth in  claim 7 , wherein the adhering the palladium catalyst comprises adhering a first amount of the palladium catalyst to the surface of the second interlaminar resin insulating layer and a second amount of the palladium catalyst to the exposed face of the first conductor circuit. 
     
     
         9 . The method as set forth in  claim 8 , wherein the first amount is greater than the second amount. 
     
     
         10 . The method as set forth in  claim 1 , wherein the substituting the electroless plating film comprises substituting the electroless plating film on the second interlaminar resin insulating layer until the electroless plating film formed on the exposed faces of the conductor circuits is completely substituted with the thin film conductor layer. 
     
     
         11 . A multilayer printed wiring board, comprising:
 a first interlaminar resin insulating layer;   a first conductor circuit formed on the first interlaminar resin insulating layer;   a second interlaminar resin insulating layer formed on the first conductor circuit and the first interlaminar resin insulating layer, the second interlaminar resin insulating layer including opening portions to expose a face of the first conductor circuit;   an electroless plating film formed on a portion of the second interlaminar resin insulating layer;   a thin film conductor layer formed on the exposed face and the electroless plating film, the thin film conductor layer having a lower ion tendency than the electroless plating film and including a metal of the exposed face of the first conductor circuit; and   an electroplating film including the metal formed on the thin film conductor layer.   
     
     
         12 . The multilayer printed wiring board as set forth in  claim 11 , wherein
 the electroless plating film includes nickel; and   the electroplating film includes copper.   
     
     
         13 . The multilayer printed wiring board as set forth in  claim 11 , wherein the first interlaminar resin insulating layer includes glass fiber as a core material.