US 12,237,191 B2
Wafer holder
Yoshihiro Omuro, Tokyo (JP)
Assigned to DISCO CORPORATION, Tokyo (JP)
Filed by DISCO CORPORATION, Tokyo (JP)
Filed on Nov. 7, 2022, as Appl. No. 18/053,082.
Claims priority of application No. 2021-189583 (JP), filed on Nov. 22, 2021.
Prior Publication US 2023/0163005 A1, May 25, 2023
Int. Cl. H01L 21/673 (2006.01)
CPC H01L 21/67376 (2013.01) [H01L 21/67353 (2013.01); H01L 21/67386 (2013.01)] 4 Claims
OG exemplary drawing
 
1. A wafer holder for use when sucking and holding a wafer, the wafer holder comprising:
a holding base having a circular holding surface, including, on a side of the holding surface, an annular first groove and an annular second groove that is surrounded by the first groove, and internally including a plurality of first suction holes opening in a region located between the first groove and the second groove on the holding surface, a plurality of second suction holes opening in a region surrounded by the second groove on the holding surface, and a suction channel in common with the first suction holes and the second suction holes and communicating therewith and opening in a back surface on a side opposite to the holding surface;
a first elastomer ring that is disposed in the first groove and protrudes in part from the holding surface; and
a second elastomer ring that is disposed in the second groove and projects in part from the holding surface,
wherein the first suction holes and the second section holes are configured in such a manner that the first suction holes each have a pressure loss greater than that at each of the second suction holes;
wherein the first suction holes are fewer in number than the second suction holes.