Patent ID: 6210555
Filing Date: 2001-04-03
Classification: C25D,H05K

Abstract:
A method for depositing a continuous layer of a metal onto a substrate having small recesses in its surface comprisingimmersing an electrically conductive substrate having a generally smooth surface having at least one small recess therein, wherein at least one transverse dimension of said recess is from about 5 micrometers to about 250 micrometers, in an electroplating bath containing ions of a metal to be deposited onto said surface,immersing a counter electrode in said plating bathpassing an electric current between said substrate and said counterelectrode,whereinsaid electric current is a modulated reversing electric current comprising a train of pulses that are cathodic with respect to said substrate and pulses that are anodic with respect to said substrate,said cathodic pulses have a duty cycle less than about 50% and said anodic pulses have a duty cycle greater than about 50%,the charge transfer ratio of said cathodic pulses to said anodic pulses is greater than one, andthe frequency of said pulse train ranges from about 10 Hertz to about 5000 Hertz.