Patent ID: 6750144
Filing Date: 2004-06-15
Classification: C25D,H01L

Abstract:
A method for filling recesses of different sizes on a semiconductor substrate comprisingimmersing a semiconductor substrate having a surface provided with recesses of different sizes in an electroplating bath containing ions of a metal to be deposited on said surface; immersing a counter electrode in said plating bath; passing an electric current between said substrate and said counterelectrode; wherein, in a first electroplating step, said 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, whereby said pulse train in said first step has a first period, said cathodic pulses have an on-time of from about 0.83 microseconds to about 50 milliseconds and said anodic pulses have an on-time of from about 42 microseconds to about 99 milliseconds, said cathodic and anodic pulses have a charge transfer ratio of said cathodic pulses to said anodic pulses that is greater than one; in a second electroplating step, said 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, whereby said pulse train in said second step has a second period, said cathodic pulses have an on-time of from about 0.83 microseconds to about 50 milliseconds and said anodic pulses have an on-time of from about 42 microseconds to about 99 milliseconds, and said cathodic and anodic pulses have a charge transfer ratio of said cathodic pulses to said anodic pulses that is greater than one; and said second period is greater than said first period.