| 摘要 |
PROBLEM TO BE SOLVED: To provide a method for producing a multiwire wiring board exhibiting excellent conductor pattern forming accuracy without lowering the connection accuracy and excellent controllability of the thickness of an insula tion layer in a build-up layer. SOLUTION: The method for producing a multiwire wiring board comprises a step for forming resin layers integrally on the surface and rear surface of a plurality of conductor pattern layers, a step for making through holes through the plurality of conductor pattern layers, a step for depositing a conductor on the inner wall of the through holes to form a circuit board, a step for forming a prepreg of nonwoven fabric integrally on at least one of the surface or rear surface of the circuit board and filling the through holes with the prepreg of nonwoven fabric to form a multilayer plate where a built-up layer is formed on at least one side of the circuit board, a step for making holes exposing an inner layer circuit selectively in the built-up layer, a step for depositing a conductor on the inner wall of the holes, and a step for forming a conductor pattern connected with the inner layer circuit on the built-up layer. |
