Workpiece Surface Processing System for Semiconductor Wafers
Systems and methods for surface processing of a semiconductor workpiece, such as a silicon carbide semiconductor wafer, are provided. An example surface processing system includes a platen configured to rotate about an axis. The example surface processing system includes a surface processing pad on the platen. The example surface processing system includes a workpiece carrier operable to bring a semiconductor workpiece into contact with the surface processing pad. The workpiece carrier includes a head and a retaining ring around at least a portion of the head. At least one of the head and the retaining ring is movable relative to each other.
1 . A surface processing system for a semiconductor workpiece, comprising:
a platen configured to rotate about an axis;
a surface processing pad on the platen;
a workpiece carrier operable to bring a semiconductor workpiece into contact with the surface processing pad, the workpiece carrier comprising a head and a retaining ring around at least a portion of the head, wherein at least one of the head and the retaining ring is movable relative to each other.
2 . The surface processing system of claim 1 , wherein the retaining ring is movable in a direction generally perpendicular to a surface of the surface processing pad independently of the head.
3 . The surface processing system of claim 1 , wherein the surface processing pad comprises a polishing pad.
4 . The surface processing system of claim 1 , wherein the surface processing pad comprises a grind disk.
5 . The surface processing system of claim 1 , wherein the head comprises an electrically conductive material.
6 . The surface processing system of claim 5 , wherein the electrically conductive material provides a conductive path from the semiconductor workpiece to a bias source.
7 . The surface processing system of claim 1 , wherein the head is operable to provide a vacuum for holding the semiconductor workpiece.
8 . The surface processing system of claim 1 , wherein the semiconductor workpiece comprises a first side that remains in electrically conductive contact with at least a portion of the head during a surface processing operation.
9 . The surface processing system of claim 1 , wherein the workpiece carrier is operable to provide a first downforce from the head on the surface processing pad that is a different magnitude relative to a second downforce from the retaining ring on the surface processing pad.
10 . The surface processing system of claim 1 , comprising one or more cavities in the head, the one or more cavities configured to modify a pressure between the semiconductor workpiece and the surface processing pad.
11 . The surface processing system of claim 10 , wherein the one or more cavities define a plurality of zones.
12 . The surface processing system of claim 10 , wherein the one or more cavities each are operable to accommodate a fluid to modify a pressure between the semiconductor workpiece and the surface processing pad.
13 . The surface processing system of claim 10 , wherein the head comprises an electrically conductive layer between the semiconductor workpiece and the one or more cavities.
14 . The surface processing system of claim 10 , wherein the head comprises a thermally conductive layer between the semiconductor workpiece and the one or more cavities.
15 . The surface processing system of claim 1 , comprising a cooling system to cool the head.
16 . The surface processing system of claim 1 , wherein the retaining ring comprises a thermoplastic material.
17 . The surface processing system of claim 1 , wherein the retaining ring has a wall thickness of about 1 millimeter to about 40 millimeters.
18 . The surface processing system of claim 1 , wherein the semiconductor workpiece comprises silicon carbide.
19 . A method for surface processing a silicon carbide semiconductor workpiece using a surface processing system, the method comprising:
providing a silicon carbide semiconductor workpiece against a surface processing pad with a workpiece carrier, the workpiece carrier comprising a head and a retaining ring around at least a portion of the head;
imparting relative motion between the retaining ring and the head; and
performing a surface processing operation by imparting relative motion between the surface processing pad and the silicon carbide semiconductor workpiece.
20 . A retaining ring for a workpiece carrier in a system for polishing semiconductor workpieces, comprising:
a plurality of grooves;
wherein the plurality of grooves are at different vertical positions along of the retaining ring.