CHEMICAL MECHANICAL POLISHING APPARATUS

摘要

PURPOSE: A CMP(chemical mechanical polishing) apparatus is provided to improve polishing uniformity at the edge of a wafer by minimizing the unevenness of a polishing pad portion contacting the edge of the wafer during a polishing process. CONSTITUTION: A platen is prepared. A polishing pad is located on the platen. A polishing head(200) pressurizes a semiconductor substrate to the polishing pad to polish the substrate. A membrane(250) holds and releases the semiconductor substrate by vacuum, located on the bottom. A retainer ring(260) prevents the semiconductor substrate to which the membrane is absorbed from being separated from the polishing head during a process. The polishing head includes the membrane and the retainer ring. The retainer ring includes an inner retainer ring(262) surrounding the membrane and an outer retainer ring(264) surrounding the inner retainer ring.