Individual Position Control for Electrodeposition Processes
Original Publication Date: 1989-Apr-01
Included in the Prior Art Database: 2005-Jan-27
In an electroplating system, the distribution of the total current of an individual substrate frequently differs, particularly as a result of the respective effective resistance of the individual areas. This resistance depends on the anode-cathode geometry, the bath agitation, the contact resistance, and other influences. Spurious effects are also produced by the usual current concentration in the peripheral areas of the substrate. In order to avoid unwanted differences in the deposited layer thickness, each substrate has a number of contact points distributed over its surface to be electroplated, and each of these contact points is connected to a separate, controllable current source, so that differences in layer thickness are prevented by appropriately varying the individual current flows.