| abstract |
The present invention provides a method for the production of a patterned structure for printed circuit boards (PCBs), or intermediate layer for multilayer PCBs, comprising: n (i) providing an electrically insulating substrate; n (ii) applying electromagnetic radiation to the substrate to selectively create in said substrate vias and/or grooves and thereby produce a patterned substrate wherein the vias and/or the grooves correspond to the desired pattern of plated vias and/or conductive tracks; n (iii) applying a solution of one or more soluble metal salts, on one or both sides of the patterned substrate obtained in step (ii) so as to form, upon drying, a metal salt-based layer on the surface of the substrate and the inner surfaces of the vias and/or the grooves; n (iv) selectively irradiate said vias and/or grooves with a laser beam; n (v) removing the metal salt-based layer from the non-irradiated surfaces of one or both sides of the substrate, while leaving said layer on the inner surfaces of the laser-irradiated vias and/or grooves; and n (vi) depositing a conductive material on said vias and/or grooves inner surfaces so as to obtain an electrically insulating substrate comprising a desired pattern of plated, conductive vias and/or conductive tracks. |