Patent ID: 6303014
Filing Date: 2001-10-16
Classification: C25D,H01L,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 reces therein wherein at least one transverse dimension of said recess is from about 5 micrometers to about 350 micrometers, in an electroplating bath containing ions of a metal to be deposited onto said surface, said electroplating bath being substantially devoid of at least one member selected from the group consisting of levelers and brighteners,immersing a counter electrode in said plating bathpassing an electric current between said substrate and said counter electrode,whereinsaid electric current is a modulated reversing electric current comprising 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 train of pulses ranges from about 10 Hertz to about 12000 Hertz.