초록 ▼

The present invention relates to a method of electrodepositing metal onto a substrate, which comprises applying a pulsed periodic reverse current across the electrodes of a plating cell utilizing a peak reverse current density and peak forward current density; and varying the ratio of peak reverse c

The present invention relates to a method of electrodepositing metal onto a substrate, which comprises applying a pulsed periodic reverse current across the electrodes of a plating cell utilizing a peak reverse current density and peak forward current density; and varying the ratio of peak reverse current density to peak forward current density in periodic cycles to provide metal deposits of uniform thickness and appearance upon the substrate. The invention also relates to a process for improving the properties of an electrodeposit, particularly on substrates having uneven surfaces or apertures, by using programmed pulse periodic reverse current modulation. More particularly, it involves varying the anodic to cathodic current density ratio, in order to improve the surface uniformity appearance, grain structure and levelling of the deposit while maintaining high current density throwing power.

대표청구항 ▼

[ What is claimed is:] [1.] A method of electroplating metal onto a substrate, which comprises applying a pulsed periodic reverse current comprising an uninterrupted, sequential forward to reverse, reverse to forward, continuously repeating pulsing sequence across the electrodes of a plating cell ut

[ What is claimed is:] [1.] A method of electroplating metal onto a substrate, which comprises applying a pulsed periodic reverse current comprising an uninterrupted, sequential forward to reverse, reverse to forward, continuously repeating pulsing sequence across the electrodes of a plating cell utilizing a peak reverse current density and a peak forward current density, and varying the ratio of the peak reverse current density to the peak forward current density in periodic cycles comprising first, second and third values of ratios of peak reverse current density to peak forward current density to provide a metal deposit of uniform appearance, fine grain structure and uniform thickness on the substrate, wherein the ratio of peak reverse current density to peak forward current density is varied sequentially during the cycle between a first value in a first time period, a second value which is different than the first value in a second time period, and a third value which is different than the second value in a third time period.