| 摘要 |
PURPOSE:To simultaneously perform excellent adhesive strength of a conductor layer with an insulating layer and viahole connection reliability by roughing a precedingly formed conductor layer of an inner layer circuit except part of an electrically connecting section through a following conductor layer and a viahole by roughing. CONSTITUTION:A circuit board having a first layer conductor circuit 1 made of a plurality of conductor patterns is formed on a board 2. A photosensitive dry film is laminated on the circuit board, and resist 3 formed with a light permeabls circle at a viahole forming position is formed. The circuit board is dipped in alkaline sodium chlorite solution, then dipped in alkaline aqueous reducing agent solution, and a roughed face 4 is formed on the conductor pattern. After a photosensitive resin insulating layer is formed, a photomask film is brought into close contact, exposed and developed to form a heat resistant resin insulating layer 6 having an opening 10. After it is dipped in an oxidizer to form a roughed face 7 on the surface of the interlayer resin insulating layer 6, it is formed with an electrolessly copper plated film 8. These steps are repeated to obtain a build-up multilayer circuit board having four interconnection layers is obtained. |
