| 摘要 |
PROBLEM TO BE SOLVED: To smoother the external layer copper foil surface to enable fine wiring process by previously filling the recess between conductors of the internal layer circuit pattern formed on the internal layer plate with an insulating resin and thereafter bonding the internal layer plate and external layer copper foil via the bonding agent layer. SOLUTION: An internal layer circuit pattern is formed on the copper clad laminated plates of both sides of the glass cloth base epoxy resin. In order to fill the recess between the conductors of the internal layer circuit pattern, varnish is adjusted using a phenol-based resin having excellent heat resistance and insulation property as the insulation resin. Next, with the screen printing process, varnish is coated on the recess between the conductors of the internal layer circuit pattern. Varnish is dried up and heated to eliminate the solvent to form the internal layer plate filling the recess between the conductors. Next, the bonding agent film with copper foil is stacked on a predetermined position of the internal layer circuit pattern and is then heated to form a multillayer printed wiring board. |
