Chemical mechanical polishing apparatus
A “black belt” phenomenon that may be caused by an eddy of a slurry may be prevented when a wafer is polished by a chemical mechanical polishing (CMP) apparatus that includes a polishing pad to be supplied with the slurry, a polishing head including a top ring adapted to hold a wafer, and a buffer ring forming a buffer space between an edge region of the wafer and an eddy region of the slurry that may be formed in front of the polishing head.
1 . An apparatus for chemical mechanical polishing, comprising:
a polishing pad to be supplied with a slurry;
a polishing head including a top ring adapted to hold a wafer; and
a buffer ring including a buffer space between an edge region of the wafer and an eddy region of the slurry formed in front of the polishing head.
2 . The apparatus of claim 1 , wherein the buffer ring is fixed to the top ring or, together with the top ring, comprise an integral unit.
3 . The apparatus of claim 1 , wherein the buffer ring has a radius of about 0.1-5 mm greater than the top ring.
4 . The apparatus of claim 2 , wherein the buffer ring has a radius of about 0.1-5 mm greater than the top ring.
5 . An chemical mechanical polishing apparatus, comprising:
a polishing pad;
a polishing head including a top ring adapted to hold a wafer; and
a buffer ring around the polishing head.
6 . The apparatus of claim 5 , wherein the buffer ring further comprises a buffer space.
7 . The apparatus of claim 5 , wherein the buffer ring is fixed to the top ring.
8 . The apparatus of claim 5 , wherein the buffer ring and the top ring comprise an integral unit.
9 . The apparatus of claim 5 , wherein the buffer ring has an annular radius of about 0.1-5 mm.
10 . The apparatus of claim 6 , wherein the buffer ring has an annular radius of about 0.1-5 mm.
11 . The apparatus of claim 6 , wherein the buffer space has an annular radius of about 0.1-5 mm.
12 . The apparatus of claim 5 , further comprising a slurry nozzle configured to supply slurry to the polishing pad.
13 . A method of chemical mechanical polishing, comprising:
polishing a wafer by pressing the wafer against a polishing pad using a polishing head including a top ring adapted to hold the wafer; and
reducing or preventing damage to an edge region of the wafer from an eddy of the slurry, using a buffer ring around the polishing head.
14 . The method of claim 13 , wherein the buffer ring is fixed to the top ring.
15 . The method of claim 13 , wherein the buffer ring and the top ring comprise an integral unit.
16 . The method of claim 13 , wherein the buffer ring has an annular radius of about 0.1-5 mm.
17 . The method of claim 13 , wherein the buffer ring further comprises a buffer space.
18 . The method of claim 17 , wherein the buffer space has an annular radius of about 0.1-5 mm.
19 . The method of claim 13 , further comprising supplying a slurry to the polishing pad.