Processing for polishing dissimilar conductive layers in a semiconductor device

A process of forming a semiconductor device comprising:

• providing a semiconductor substrate having a conductive member;
• depositing an insulating layer over the semiconductor substrate, including over the conductive member;
• forming a via opening in the insulating layer which exposes the conductive member;
• depositing a first conductive layer over the insulating layer, including into the via opening;
• depositing a second conductive layer, different in composition from the first conductive layer, on the first conductive layer;
• providing a polisher having a polishing pad;
• polishging the second conductive layer using a first polishing flid dispensed onto the polishing pad at least until the first conductive layer is exposed;
• and
• polishing the first conductive layer using a second polishing fluid, wherein an oxidizing component of the second polishing fluid is different than an oxidizing component of the first polishing fluid.