A process for producing an adhesive layer on a copper surface by depositing a tin alloy and formed therefrom layered product

A process for producing an adhesive layer on a copper surface by depositing a tin alloy by providing a copper surface with an aqueous plating solution consisting of: 1-50 wt .-% of at least one inorganic acid selected from the group consisting of hydrochloric acid, sulfuric acid, nitric acid, fluoroboric acid and phosphoric acid or at least one organic acid selected from the group consisting of carboxylic acid, alkane sulfonic acid and aromatic sulfonic acids; 0.05-10 wt .-% tin salt or tin oxide, 0.1-20 wt .-% soluble salts or oxides of another metal selected from the group consisting of silver, zinc, aluminum, titanium, bismuth, chromium, iron, cobalt, nickel, palladium, gold and / or platinum, 1-50 wt .-% of a reaction accelerator selected from the group consisting of thiourea, 1,3-dimethyl thiourea, 1,3-diethyl-2-thiourea and / or thioglycolic acid and 1-80 wt .-% of a solvent selected from glycol and / or glycol esters brought to form a diffusion alloy layer is in contact and subsequently, a part of the upper diffusion alloy layer is selectively removed liquid to a thickness of not more than 1 microns by means of an etching.