Process for the electrolytic deposition of metallic layers having predetermined physical properties and arrangement for carrying out the process

摘要

PCT No. PCT/DE94/01542 Sec. 371 Date Apr. 22, 1996 Sec. 102(e) Date Apr. 22, 1996 PCT Filed Dec. 23, 1994 PCT Pub. No. WO95/18251 PCT Pub. Date Jul. 6, 1995A process and apparatus for electrolytically depositing a uniform metal layer onto a workpiece is provided. The workpiece, for example a circuit board, serves as a cathode. The anode is insoluble and dimensionally stable. Both anode and cathode are immersed in a plating solution contained in an electrolytic container. The solution includes (a) ions of the metal to be deposited on the workpiece, (b) an additive substance for controlling physical-mechanical properties of the metal to be deposited, such as brightness, and (c) an electro-chemically reversible redox couple forming oxidizing compounds when contacting the anode. A metal-ion generator is provided, supplying metal parts of the metal to be deposited onto the workpiece; The plating solution is circulated between the container and the ion generator for maintaining a reaction between the oxidizing compounds and the metal parts for forming metal ions. The plating solution is controllably re-circulated into the container so that a low concentration of the oxidizing compounds is present in the plating solution adjacent to the workpiece.