Method for manufacturing high-density multilayer printed circuit boards

A method for making high-density multilayer printed circuit boards comprising the following steps:

• (a) forming a pair of first electrically conductive layers on top and bottom sides of a dielectric substrate;
• (b) forming at least one first via hole through one of said first electrically conductive layers;
• (c) forming at least one blind hole through said dielectric substrate in alignment with said through hole using a conformal laser drilling technique and filling said blind hole with an electrically conductive blind hole filling material;
• (d) forming a circuit pattern from said first electrically conductive layer;
• (e) forming a first electrically insulating layer on said first electrically conductive layer;
• (f) forming at least one second via through said first electrically insulating layer using a non-conformal laser drilling technique to expose a top surface of said circuit pattern;
• (g) conformally coating a second electrically conductive layer covering said top surface of said circuit pattern, a side surface of said second via hole, and a top surface of said first electrically insulating layer, by electroplating;
• (h) forming a second electrically insulating layer on said second electrically conductive layer and, at the same time, filling said second via hole with the same electrically insulating material;
• (i) removing said second electrically insulating layer and said second electrically conductive layer above said second via hole to cause said second electrically conductive layer to assume the shape of a cup and expose top edges of said second electrically conductive layer;
• (j) forming a third electrically conductive layer on said first electrically insulating layer, wherein said third electrically conductive layer is in contact with said top edges of said second electrically conductive layer so that it is electrically connected to said circuit pattern;
• (k) forming another circuit pattern from said third electrically conductive layer;
• and
• (l) repeating steps (e) through (k) if one or more electrically conductive conductive patterns are needed.