| 摘要 |
A polishing head of a CMP apparatus is provided to restrain an edge portion of a wafer from being excessively polished by using a buffer ring. A polishing head of a CMP apparatus includes a polishing housing, a retainer ring, a buffer ring and a buffer ring lifting unit. The polishing housing(110) is used for adsorbing or pressuring a wafer. The retainer ring(120) is installed under the polishing housing corresponding to a periphery of the wafer. The buffer ring(130) is installed at the polishing housing to move up and down between the retainer ring and the wafer. The buffer ring is used for restraining a polishing pad from being protruded. The buffer ring lifting unit(140) is installed at the polishing housing to move the buffer ring up and down.
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