Methods and apparatus for electrical, mechanical and/or chemical removal of conductive material from a microelectronic substrate

A method for removing material from a face surface of a microelectronic substrate, comprising:

• providing a microelectronic substrate having a first conductive material disposed adjacent to a second conductive material, with the second conductive material having a different composition than the first conductive material;
• engaging the first conductive material with a polishing surface of a polishing pad;
• electrically coupling a first conductive material of the microelectronic substrate to a source of electrical potential by positioning first and second electrodes apart from the face surface and disposing a first electrolytic fluid between the face surface and the electrodes while the face surface is engaged with the polishing surface of the polishing pad, with both the electrodes in fluid communication with the first electrolytic fluid;
• oxidizing at least a portion of the first conductive material by passing an electrical current through the first conductive material while the first conductive material is engaged with the polishing surface;
• removing the portion of the first conductive material from the microelectronic substrate by moving at least one of the microelectronic substrate and the polishing pad relative to the other;
• engaging the second conductive material with the polishing surface of the polishing pad after removing the portion of the first conductive material;
• electrically coupling the second conductive material of the microelectronic substrate to a source of electrical potential by positioning the first and second electrodes apart from the face surface and disposing a second electrolytic fluid between the face surface and the electrode while the face surface is engaged with the polishing surface of the polishing pad, with both the electrodes in fluid communication with the second electrolytic fluid;
• oxidizing at least a portion of the second conductive material by passing an electrical current through the second conductive material while the second conductive material is engaged with the polishing surface;
• and
• removing the portion of the second conductive material from the microelectronic substrate by moving at least one of the microelectronic substrate and the polishing pad relative to the other.

A method for endpointing removal of material from a microelectronic substrate, comprising:

• engaging the microelectronic substrate with a polishing surface of a polishing pad, the microelectronic substrate having a substrate material, a dielectric material adjacent to the substrate material, and a conductive material adjacent to the dielectric material;
• electrically coupling the conductive material of the microelectronic substrate to a source of electrical potential;
• oxidizing at least a portion of the conductive material by passing an electrical current through the conductive material from the source of electrical potential while the microelectronic substrate is engaged with the polishing surface of the polishing pad;
• removing the portion of the conductive material from the microelectronic substrate by moving at least one of the microelectronic substrate and the polishing pad relative to the other to expose the dielectric material;
• and
• halting further removal of material from the microelectronic substrate by engaging the dielectric material with the polishing surface of the polishing pad.