Multilayer flexible wiring circuit board and its manufacturing method

A method of producing a multilayer flexible wired circuit board comprising:

• preparing a double-sided substrate in which conductor layers are laminated on both sides of an insulating layer, respectively, said double-sided substrate having at least one through hole;
• preparing a single-sided substrate including a conductor layer connected on one side to an insulating layer, and to an adhesive layer on another side of said conductor layer;
• and
• bonding said conductor layer of said single-sided substrate to the conductor layers of said double-sided substrate, through said adhesive layer connected to said conductor layer;
• wherein in said bonding step, said adhesive layer is pressed into said at least one through hole to connect the double-sided substrate to said conductor layer of said single-sided substrate.

A multilayer flexible wired circuit board comprising:

• a double-sided substrate having conductor layers laminated on both sides of an insulating layer, the double-sided substrate containing at least one through hole;
• and
• at least one single-sided substrate having a conductor layer connected to an insulating layer on one side and connected to an adhesive layer on another side of said conductor layer, said adhesive layer having at least one conductive passage in which solder is disposed;
• wherein said single-sided substrate and said double-sided substrate are bonded together by said adhesive layer being disposed through said at least one through hole in said double-sided substrate;
• and
• wherein said conductive passage provides an electrical connection between said conductor layers of said double-sided substrate and said single-sided substrate.