COPPER PLATING OF MULTILAYER PRINTED WIRING BOARDS.

A procedure is outlined for investigating complex electrochemical phenomena which arise in the fabrication of multilayer printed wiring boards. The procedure breaks the overall system into three different scale sizes, two of which are crucial to plating thickness distribution control. The factors which control the current distribution on these two scales are clarified with use of dimensionless analysis. Experimental data from widely diverse systems confirm the dimensionless parameters. Experimental data from widely diverse systems confirm the dimensionless parameters and provide intuitive insight into the electrochemical behavior of the overall system. More detailed theoretical calculations are employed to provide quantitative information. The resulting framework illustrates the interplay of geometric, ohmic, charge transfer, mass transport and plating additive effects. Quantitative design criteria are thereby developed for assuring a high quality product.