Selective control of thickness of electroplated coatings - esp. on printed circuit boards, via electroplating tank contg. capacitor grip controlling flow of metal ions

摘要

The coating is to be deposited esp. on the conductor paths (4) on a printed circuit board (5) immersed in a plating tank together with an electrode (2). In the tank and between electrodes (4,5) is a grid (6) which is insulated from the electrolyte but contains holes through which the electrolyte can flow. Grid (6) is divided into individual zones (7) which can be charged to different potentials, esp. by using each zone (7) as one metal electrode of a capacitor, the other electrode of which is a single common electrode (2) also forming the anode for electroplating. All electrodes (7) are pref. fed with electric power via a controller supplied with programmed data, e.g. via punched or magnetic tape. Despite the irregular distribution of paths (4) on board (5), all the paths can be provided with the same thickness of an electroplated metal coating.