| 摘要 |
PURPOSE:To obtain a multilayer printed circuit board causing no defective insulation by applying insulating resin added with inorganic filler onto the surface of an inner layer board and filling a common clearance and non-common clearance sections therewith then performing thermal pressure molding thereby preventing occurrence of crack in the clearance when a through-hole is formed. CONSTITUTION:A double-sided copper-clad lamination board 2 employing copper foil 1 of required thickness is prepared then a through-hole is drilled thus forming a common clearance section 3. Then a non-common clearance section 4 is formed through photo-etching thus producing an inner layer board 5 which is employed as a source/ground layer. Then insulation resin such as insulation resin 6 mixed with fillers is applied onto the opposite faces of the inner layer board 5 through screen printing so that the common clearance section 3 and the non-clearance section 4 are filled with the insulation resin 6 mixed with fillers, thereafter it is thermally pressurized through a vacuum press thus producing an inner layer board 7. Then the inner layer board 7 is thermally laminated on an outer conductor layer 9 through a prepreg 8 and subjected to boring, through-hole plating and etching thus producing a multilayer printed circuit board 10. |
