Multilayer printed wiring board and method of manufacturing the same

Abstract

A structure of a multilayer printed wiring board having a wiring lead-out port can be easily formed. A large number of products can be easily manufactured with good size reproducibility. A method of manufacturing the same is also are disclosed. The multilayer printed wiring board is characterized by having a signal circuit conductor perfectly covered by an earth circuit in its inside and a wiring lead-out port. A signal circuit conductor having a branch pattern is preferable. The multilayer printed wiring board is manufactured by selectively etching the copper of a cladding sheet manufactured by bonding a copper foil to a nickel foil with 0.1-3% reduction and forming a signal circuit conductor perfectly covered by an earth circuit and the wiring lead-out port.

1 . A multilayer printed wiring board characterized in including a signal circuit conductor completely covered by an earth circuit at an inner portion thereof as well as providing a wiring lead-out port.  
     
     
         2 . The multilayer printed wiring board according to  claim 1 , wherein the signal circuit conductor includes a branch pattern.  
     
     
         3 . A method of manufacturing a multilayer printed wiring board, characterized in forming a signal circuit conductor completely covered by an earth circuit and a wiring lead-out port at an inner portion thereof by selective etching of copper with regard to a cladding sheet for the multilayer printed wiring board manufactured by bringing a copper foil material and a nickel foil material into press contact with each other by a reduction of 0.1 to 3%.  
     
     
         4 . The method of manufacturing a multilayer printed wiring board according to  claim 3 , wherein the cladding sheet for the multilayer printed wiring board comprises five layers of copper/nickel/copper/nickel/copper.  
     
     
         5 . The method of manufacturing a multilayer printed wiring board according to  claim 3  or  4 , wherein the cladding sheet for the multiplayer printed wiring board is manufactured by bringing the copper foil material provided with nickel plating at one face or two faces thereof and other copper foil material or a copper foil material provided with nickel plating at one face thereof into press contact with each other by the reduction of 0.1 to 3%.  
     
     
         6 . A method of manufacturing a multilayer printed wiring board, characterized in forming a signal circuit conductor completely covered by an earth circuit at an inner portion thereof by selective etching of copper with regard to a cladding sheet for the multilayer printed wiring board manufactured by bringing a copper foil material and a silver foil material into press contact with each other by a reduction of 0.1 to 3%.  
     
     
         7 . The method of manufacturing a multiplayer printed wiring board according to  claim 6 , wherein the cladding sheet for the multilayer printed wiring board comprises three layers of copper/silver/copper.  
     
     
         8 . The method of manufacturing a multilayer printed wiring board according to  claim 6  or  7 , wherein the cladding sheet for the multilayer printed wiring board is manufactured by bringing a copper foil material provided with silver plating at one face thereof and other copper foil material into press contact with each other by a reduction of 0.1 to 3%.  
     
     
         9 . The method of manufacturing a multilayer printed wiring board according to any one of  claims 3  to  5 , characterized in forming a resist pattern for forming a circuit shield wall and for forming the wiring lead-out port at the copper layer on the one face of the cladding sheet for the multilayer printed wiring board according to any one of  claims 3  to  5 , thereafter carrying out selective etching of copper to thereby form the circuit shield wall and the wiring lead-out port, removing the nickel layer, successively coating an insulating resin on an etching face, thereafter forming a resist pattern for forming a circuit shield wall at a copper layer on a rear face of the cladding sheet, thereafter carrying out selective etching of copper to thereby form the circuit shield wall, etching the intermediate copper layer to thereby form a signal circuit, coating an insulating resin on an etching face and plating copper on two faces thereof to thereby form the shield wall.  
     
     
         10 . The method of manufacturing a multilayer printed wiring board according to  claims 6  to  8 , characterized in forming a resist pattern for forming a circuit shield wall or for forming a wiring lead-out port at the copper layer on one face of the cladding sheet with regard to the cladding sheet for a multilayer printed wiring board according to any one of  claims 6  to  8 , thereafter carrying out selective etching of copper to thereby form the circuit shield wall, successively coating an insulating resin on an etching face, thereafter forming a resist pattern for forming a circuit shield wall at the copper layer on a rear face of the cladding sheet, thereafter carrying out selective etching of copper to thereby form the circuit shield wall, forming a signal circuit by etching the intermediary copper layer, coating an insulating resin on an etching face and thereafer plating copper at two faces other than a portion for constituting a wiring lead-out port to thereby form the shield wall.  
     
     
         11 . The method of manufacturing a multilayer printed wiring board according to  claim 9  or  10 , wherein the signal circuit conductor is constituted by a shape including a branch pattern.  
     
     
         12 . A method of forming a wiring lead-out port at a multilayer printed wiring board, characterized in forming a resist pattern for forming the wiring lead-out port at a copper layer on one face of a cladding sheet for a multilayer printed wiring board according to any one of  claim 3  to  5 , thereafter carrying out selective etching of copper to thereby form a shield wall of the wiring lead-out port, removing a nickel layer, successively coating an insulating resin on an etching face, thereafter etching a copper layer on a rear face of the cladding sheet and coating an insulating resin on an etching face.  
     
     
         13 . A method of forming a wiring lead-out port on the multilayer printed wiring board according to any one of  claims 6  to  8 , characterized in forming a resist pattern for forming the wiring lead-out port at a copper layer on one face of a cladding sheet for the multiplayer printed wiring board according to any one of  claims 6  to  8 , thereafter carrying out selective etching of copper to thereby form a shield wall of the wiring lead-out port, thereafter successively coating an insulating resin on an etching face, thereafter etching a copper layer on a rear face of the cladding sheet to thereby form a circuit shield wall, forming a signal circuit by etching the intermediary silver layer and coating an insulating resin on an etching face.