Polishing control method
AssigneeSpeedfam Corporation
InventorsWayne Mattingly, Hatsuyuki Arai
Life of this patent
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Abstract
Polishing of wafers, such as wafers of semiconductive material is carried out by mounting the wafer to a carrier, and pressing the wafer against a polishing pad carrying a polishing media. An antenna is placed beneath the polishing pad and electrical energization is applied between the carrier assembly and the antenna. The electrical energization preferably includes a direct current bias, but may also include ratio frequency carrier injection signal. The noise associated with ionic disassociation is monitored to assess ongoing polishing activity, on a real time basis.
Claims14
A method for observing polishing activity on a real time basis, in an ongoing polishing operation, comprising:
- providing an electrically nonconductive table;
- providing a polishing pad on the table;
- providing a carrier assembly disposed above the polishing pad;
- carrying a workpiece to be polished in the carrier assembly;
- moving at least one of the table and carrier assembly with respect to the other so as to generate a polishing activity between the workpiece and the pad causing a region of ionic disassociation of the workpiece;
- disposing an antenna comprising a thin flexible sheet of electrically conductive material between the pad and the table;
- injecting a radio frequency carrier signal between the carrier assembly and the antenna, through the region of ionic disassociation of the workpiece with the radio frequency carrier signal being modified by the ionic disassociation associated with the polishing activity;
- and
- detecting ionic disassociation generated by the polishing activity with the antenna.
A method for observing polishing activity on a real time basis, in an ongoing polishing operation, comprising:
- providing an electrically nonconductive table;
- providing a polishing pad on the table;
- providing a carrier assembly disposed above the polishing pad;
- carrying a workpiece to be polished in the carrier assembly;
- moving at least one of the table and carrier assembly with respect to the other so as to generate a polishing activity between the workpiece and the pad, causing a region of ionic disassociation of the workpiece;
- disposing an antenna comprising a thin flexible sheet of electrically conductive material between the pad and the table;
- coupling an electrical energization signal between the carrier assembly and the antenna;
- detecting ionic disassociation generated by the polishing activity with the antenna;
- and
- wherein the electrical energization signal injects a radio frequency carrier signal through the region of ionic disassociation of the workpiece with the radio frequency carrier signal being modified by the ionic disassociation associated with the polishing activity.
A method for observing polishing activity on a real time basis, in an ongoing polishing operation, comprising:
- providing an electrically nonconductive table;
- providing a polishing pad on the table;
- providing a carrier assembly disposed above the polishing pad;
- carrying a workpiece to be polished in the carrier assembly;
- moving at least one of the table and carrier assembly with respect to the other so as to generate a polishing activity between the workpiece and the pad causing a region of ionic disassociation of the workpiece;
- disposing an antenna comprising a thin flexible sheet of electrically conductive material between the pad and the table;
- coupling a direct current bias voltage across the carrier assembly, the region of ionic disassociation and the antenna;
- fluidically coupling the direct current bias voltage to the antenna through a first feedthrough bushing comprising first and second interfitting parts with a fluid conductive medium between the parts;
- and
- detecting ionic disassociation, generated by the polishing activity, with the antenna.
Dependencies are inferred from the claim text.