METHOD FOR PRODUCING MULTI-LAYER CIRCUITS

摘要

The invention relates to a method for producing sequentially constructed printed circuit boards with an uneven number of conductor layers on both sid es of the laminate core, characterized by the following steps: (A) a circuit board provided with conductor structures (2) on one side only is coated on both sides with a dielectric (3) containing a photopolymer or a thermally hardening polymer; (B) contact holes (vias) (5) are structured on the side that includes the conductor structures (2) by exposing the dielectric (3) th at contains a photopolymer or thermally hardening polymer to light and by subsequent developing with a solvent or by laser- drilling through the conta ct holes (vias) (5) into the dielectric (3) containing a photopolymer or thermally hardening polymer; (C) a copper layer (6) is deposited on both sid es of the circuit board thus obtained; (D) conductor structures are formed on t he front side and full etch removal occurs on the rear side in case a further asymmetric structure is to be produced, or on both sides of the circuit boar d if no further structure occurs or the structure is symmetrical, by means of selective etching with the aid of resists;(E) steps (A) (D) are repeated in case a further unsymmetrical structure is to be produced or (A) and subseque nt structuring (F) onboth sides of the dielectric layer followed by (C) and (D) if a further symmetrical structure is required.