The present invention relates to a method for removing an organic resin from a
copper surface on a
dielectric substrate containing conductive through-holes (TH) and / or conductive blind microvias (BMV), comprising the following steps: (i) applying an organic paste to the
dielectric substrate to fill the through-holes (TH) and / or blind microvias (BMV) with the organic paste, wherein, after step (i), at least a portion of the surface of the
dielectric substrate is covered with the organic paste; and (ii) curing the organic paste to convert it into a solidified organic resin, wherein, after step (ii), the dielectric (iii) a step of
coating at least a portion of the surface of the substrate with an organic resin; and a step of chemically treating the
dielectric substrate with a non-aqueous composition to remove the organic resin from the surface of the substrate in order to obtain a chemically treated surface of the substrate, wherein the non-aqueous composition comprises: a) at least one high-
boiling point solvent having a
boiling point of at least 100°C in a concentration of 80% to 95% by
mass; b) at least one
carboxylic acid in a concentration of 5% or more and less than 20% by
mass; c) at least one anionic aromatic surfactant in a concentration of 0.25% or more and less than 1.5% by
mass; and d) 0.25% or more and 1.A step comprising: (iv-1) a step of mechanically treating the chemically treated surface of the substrate obtained after step (iii) with an
abrasive to remove residual organic resin from the chemically treated surface of the substrate in order to obtain a mechanically treated surface of the substrate; and / or (iv-2) a step of wet chemically treating the chemically treated surface of the substrate obtained after step (iii) with an oxidizing solution containing an
oxidizing agent to remove residual organic resin from the chemically treated surface of the substrate in order to obtain a wet chemically treated surface of the substrate; (v The present invention relates to a method comprising: (i) in some cases, a step of depositing a conductive material, preferably electrolytically removing a
coating metal, on a mechanically treated surface obtained after step (iv-1) or on a wet-chemically treated surface of the substrate obtained after step (iv-2) to obtain a conductive surface of the substrate; and (vi) in some cases, a step of further electrolytically removing a
coating metal on the conductive surface of the substrate obtained after an optionally selected step (v) or on a mechanically treated surface of the substrate obtained after step (iv-1) or on a wet-chemically treated surface of the substrate after step (iv-2) in order to obtain an electrolytic
metal coating surface.