Wafer chuck with aerodynamic design for turbulence reduction
A rotatable wafer chuck includes chuck arms and wafer holders that are aerodynamically shaped to reduce turbulence during rotation. A wafer holder may include a friction support and an independently rotatable vertical alignment member and clamping member that is shaped to reduce drag. The shape reduces turbulence during edge bevel etching to improve the uniformity of the edge exclusion and during high-speed rotation to improve particle performance.
1. A method of processing a semiconductor wafer in a wafer chuck, the method comprising:
a. providing the semiconductor wafer to the wafer chuck having chuck arms and a plurality of wafer holders at ends of the chuck arms; and
b. rotating the wafer chuck thereby rotating the semiconductor wafer; and
wherein each of the wafer holders comprises a turbulence reducing structure comprising a curved or angled aerodynamically shaped surface, and
wherein the turbulence reducing structure is oriented and configured such that, when rotating during post-electrofill wafer processing using a stream of fluid on at least a portion of the semiconductor wafer facing the turbulence reducing structure, the wafer holders do not substantially affect the stream of fluid and thereby reduces process variations on the semiconductor wafer.
2. The method of claim 1 , further comprising:
a. etching metal from the semiconductor wafer while it rotates.
3. The method of claim 1 , further comprising:
a. cleaning the semiconductor wafer while it rotates; and
b. drying the semiconductor wafer while it rotates.
4. The method of claim 1 , further comprising:
a. aligning the semiconductor wafer; and
b. clamping the semiconductor wafer while it rotates at a high speed.
5. The method of claim 1 , wherein the plurality of wafer holders cover less than 25% of wafer perimeter when holding the semiconductor wafer.
6. The method of claim 1 , wherein the wafer chuck is rotated at a speed sufficient to pivot an alignment member each of the plurality of wafer holders outward relative to a center of the wafer chuck to expose an edge of the semiconductor wafer.
7. The method of claim 1 , further comprising providing the stream of fluid to the semiconductor wafer to etch or clean the semiconductor wafer.
8. A method of processing a wafer in a wafer chuck, the method comprising:
providing the wafer to the wafer chuck having a plurality of chuck arms and a plurality of wafer holders at ends of the plurality of chuck arms to hold the wafer, each of the plurality of wafer holders comprising a forward end and a rear end along a direction of rotation of the wafer chuck, and a turbulence reducing structure on the forward end, the rear end, or both ends of each wafer holder;
rotating the wafer chuck in the direction of rotation to thereby rotate the wafer; and
providing a stream of fluid to the wafer to etch or clean the wafer,
wherein the wafer holders do not substantially affect the stream of fluid to the wafer and thereby reduces process variations on the wafer, and
wherein the turbulence reducing structure comprises a curved or angled aerodynamically shaped surface and is oriented and configured such that, when rotating during post-electrofill wafer processing using stream of fluid on at least a portion of the wafer facing the turbulence reducing structure, the wafer holders do not substantially affect the stream of fluid.
9. The method of claim 8 , wherein the stream of fluid comprises etchant to etch metal from the wafer while it rotates.
10. The method of claim 8 , wherein the stream of fluid comprises deionized water to clean the wafer while it rotates.
11. The method of claim 10 , further comprising after providing the stream of fluid, drying the wafer while it rotates.
12. The method of claim 8 , further comprising aligning the wafer; and clamping the wafer while it rotates at a speed between 750 rpm and 2000 rpm.
13. The method of claim 8 , wherein the stream of fluid flows down an edge of the wafer and to a backside of the wafer unimpeded.
14. The method of claim 8 , wherein less than 25% of wafer perimeter is covered by the plurality of wafer holders.
15. The method of claim 8 , wherein the wafer chuck is rotated at a speed sufficient to pivot an alignment member of each of the plurality of wafer holders outward relative to a center of the wafer chuck to expose an edge of the wafer.