In the substrate for an electrical circuit, at least one side surface (7) of the metallic section (2`) is chamfered after etching. The removing of material gives a gap between the base line and a theoretical height line of about 70% of the thickness of the metallic section (2`), parallel to the surface of the insulating layer (1) and across the side surface (7). The chamfering gives a setback of about 0.05-1.0mm. Also claimed is a mfg. process where the substrate is processed with a further etching stage after the mask has been removed, so that material is removed which amounts to 22-20% of the thickness of at least one metallic section (2`).
