| 摘要 |
PROBLEM TO BE SOLVED: To provide a method for producing a wiring board having highly reliable via holes by removing residue in fine via holes completely. SOLUTION: First wiring layers 2a, 2b and an insulation layer 3 are formed on the opposite sides of an insulating substrate 1. Via holes 4 are made at specified positions of the insulation layer 3 by laser machining. The via holes 4 are then filled with residue removing powder by doctoring to form a residue removing powder filling layer 5. The substrate on which the residue removing powder filling layer 5 is formed is then immersed into a residue removing liquid in order to dissolve the residue removing powder filling layer 5 thus removing the residue in the via holes 4. Subsequently, a via hole 6 and second wiring layers 7a, 7b are formed in the via holes 4 from which the residue is removed and on the insulation layer 3 thus obtaining a highly reliable four layer high density wiring board. |
