Method for producing rigid-type multilayer printed wiring board

Claim 1

A method for producing a rigid-type multilayer printed wiring board of the type in which a multilayer printed wiring sheet substantially comprising a thin insulating resin layer, metal foil printed wiring layer and a plurality of conductive holes formed through the two layers is bonded onto a metal board through an insulation laminate, said method comprising the steps of: preparing a multilayer printed wiring interlayer sheet comprising said multilayer printed wiring sheet in which a printed wiring pattern unprocessed metal foil is left on one surface thereof, the other surface being already subjected to a given printed wiring forming process; bonding the other surface of said interlayer sheet to a surface of a metal board through an insulation laminate; and forming a desired printed wiring pattern on said printed wiring pattern unprocessed metal foil on said one surface.

Claim 2

A method for producing a rigid-type multilayer printed wiring board of the type in which a multilayer printed wiring sheet substantially comprising a thin insulating resin layer, metal foil printed wiring layer and a plurality of conductive holes formed through the two layers is bonded onto a metal board through an insulation laminate, said method comprising the steps of: preparing a multilayer printed wiring interlayer sheet comprising said multilayer printed wiring sheet in which a printed wiring pattern unprocessed metal foil is left on one surface thereof, the other surface being already subjected to a given printed wiring forming process; bonding the other surface of said interlayer sheet to a surface of a metal board through an insulation laminate; and forming a desired printed wiring pattern on said printed wiring pattern unprocessed metal foil on said one surface.

Claim 11

A method for producing a rigid-type multilayer printed wiring board comprising the following sequence of steps: (a) preparing printed wiring layer sheets by preliminarily forming the necessary printed wiring including conductive through-holes in a desired number of flexible metal foil-bonded sheets each thereof having a metal foil bonded to at least one side thereof; (b) preparing a multilayer printed wiring sheet by laminating a desired number of said printed wiring layer sheets through at least one insulating adhesive layer in such a manner that the outermost layer metal foils on the sides thereof are not subjected to a printed wiring forming process; (c) preparing a multilayer printed wiring interlayer sheet by forming a first outermost layer printed wiring including through-holes on a first outermost layer of said multilayer printed wiring sheet and leaving only a second outermost layer metal foil as being formed with no printed wiring; (d) bonding said multilayer printed wiring interlayer sheet to a metal board with said first outermost layer printed wiring processed side service as a bonding surface; and (e) forming a second outermost layer printed wiring on said second outermost layer metal foil.

Claim 12

A method for producing a rigid-type multilayer printed wiring board comprising the following sequence of steps: (a) preparing printed wiring layer sheets by preliminarily forming the necessary printed wiring including conductive through-holes in a desired number of flexible metal foil-bonded sheets each thereof having a metal foil bonded to at least one side thereof; (b) preparing a multilayer printed wiring sheet by laminating a desired number of said printed wiring layer sheets through at least one insulating adhesive layer in such a manner that the outermost layer metal foils on the sides thereof are not subjected to a printed wiring forming process; (c) preparing a multilayer printed wiring interlayer sheet by forming a first outermost layer printed wiring including through-holes on a first outermost layer of said multilayer printed wiring sheet and leaving only a second outermost layer metal foil as being formed with no printed wiring; (d) bonding said multilayer printed wiring interlayer sheet to a metal board with said first outermost layer printed wiring processed side service as a bonding surface; and (e) forming a second outermost layer printed wiring on said second outermost layer metal foil.

Claim 16

A method for producing a rigid-type multilayer printed wiring board comprising the following sequence of steps: (a) performing on a flexible double-sided metal foil-bonded sheet having a metal foil bonded to each side thereof an operation of forming a desired number of holes and an operation of forming a first layer printed wiring pattern on one of said metal foils in a predetermined order; (b) performing a process of electrodeless plating to make conductive at least the insides of said holes and said first layer printed wiring pattern processed surface of said flexible double-sided metal foil-bonded sheet formed with said holes and said first layer printed wiring pattern; (c) applying a resist layer to the entire surface excluding at least the plated through-hole portions and pad portions of said flexible double-side metal foil bonded sheet having at least the insides of said holes and said first layer printed wiring pattern processed surface made conductive by said electrodeless plating and then subjecting at least said plated through-hole portions and pad portions to thick plating by an electroplating process; (d) removing said resist layer with a removing solution; (e) removing by etching said electrodeless plated copper layer appearing from below said removed resist layer to form a first layer printed wiring on one side of said flexible double-side metal foil-bonded sheet; (f) bonding said flexible double-side metal foil-bonded sheet having said first layer printed wiring including through-hole portions formed on one side thereof to a surface of a metal board through an isolation laminate with said first layer printed wiring processed side serving as a bonding surface; and (g) forming a second layer printed wiring on said metal foil not formed with said first layer printed wiring and bonded to the other side of said flexible double-sided metal foil-bonded sheet bonded to said metal board.

Claim 17

A method for producing a rigid-type multilayer printed wiring board comprising the following sequence of steps: (a) performing on a flexible double-sided metal foil-bonded sheet having a metal foil bonded to each side thereof an operation of forming a desired number of holes and an operation of forming a first layer printed wiring pattern on one of said metal foils in a predetermined order; (b) performing a process of electrodeless plating to make conductive at least the insides of said holes and said first layer printed wiring pattern processed surface of said flexible double-sided metal foil-bonded sheet formed with said holes and said first layer printed wiring pattern; (c) applying a resist layer to the entire surface excluding at least the plated through-hole portions and pad portions of said flexible double-side metal foil bonded sheet having at least the insides of said holes and said first layer printed wiring pattern processed surface made conductive by said electrodeless plating and then subjecting at least said plated through-hole portions and pad portions to thick plating by an electroplating process; (d) removing said resist layer with a removing solution; (e) removing by etching said electrodeless plated copper layer appearing from below said removed resist layer to form a first layer printed wiring on one side of said flexible double-side metal foil-bonded sheet; (f) bonding said flexible double-side metal foil-bonded sheet having said first layer printed wiring including through-hole portions formed on one side thereof to a surface of a metal board through an isolation laminate with said first layer printed wiring processed side serving as a bonding surface; and (g) forming a second layer printed wiring on said metal foil not formed with said first layer printed wiring and bonded to the other side of said flexible double-sided metal foil-bonded sheet bonded to said metal board.

Claim 18

A method of producing a rigid-type multilayer printed wiring board, comprising the following sequence of steps: (a) performing an operation of forming a desired number of holes though a flexible double-sided metal foil bonded sheet comprising an insulating resin foil having a metal foil bonded to each side thereof; (b) performing an electrodeless copper plating process to make conductive the insides of said holes formed through said flexible double-side metal foil-bonded sheet by said hole forming operation; (c) applying a thick plating by an electroplating process to the entire surface of said flexible double-sided metal foil-bonded sheet including said hole insides made conductive by said electrodeless copper plating process; (d) forming a first layer printed wiring on one side of said thick plated flexible double-sided metal foil-bonded sheet; (e) bonding said flexible double-sided metal foil-bonded sheet formed with said first layer printed wiring including through-hole portions on one side thereof to a surface of a metal board through an isolation laminate with said first layer printed wiring processed side serving as a bonding surface; and (f) forming a second layer printed wiring on said metal foil not formed with said first layer printed wiring and bonded to the other side of said flexible double sided metal foil-bonded sheet bonded to said metal board.

Claim 19

A method of producing a rigid-type multilayer printed wiring board, comprising the following sequence of steps: (a) performing an operation of forming a desired number of holes though a flexible double-sided metal foil bonded sheet comprising an insulating resin foil having a metal foil bonded to each side thereof; (b) performing an electrodeless copper plating process to make conductive the insides of said holes formed through said flexible double-side metal foil-bonded sheet by said hole forming operation; (c) applying a thick plating by an electroplating process to the entire surface of said flexible double-sided metal foil-bonded sheet including said hole insides made conductive by said electrodeless copper plating process; (d) forming a first layer printed wiring on one side of said thick plated flexible double-sided metal foil-bonded sheet; (e) bonding said flexible double-sided metal foil-bonded sheet formed with said first layer printed wiring including through-hole portions on one side thereof to a surface of a metal board through an isolation laminate with said first layer printed wiring processed side serving as a bonding surface; and (f) forming a second layer printed wiring on said metal foil not formed with said first layer printed wiring and bonded to the other side of said flexible double sided metal foil-bonded sheet bonded to said metal board.