Chemical mechanical polishing apparatus and method

A chemical mechanical polishing (CMP) apparatus, comprising:

• a polishing pad having a polishing surface;
• a polishing head configured to hold a wafer in contact with the polishing surface during a polishing process, wherein the polishing head comprises:
• a retaining ring disposed on a bottom of the polishing head and configured to retain the wafer;
• at least one fluid channel formed in the polishing head and fluidly connected to a plurality of vacuum holes formed on a bottom surface of the retaining ring facing the polishing surface;
• and
• an exhaust system fluidly connected to the at least one fluid channel, wherein the exhaust system is configured to generate a vacuum in the at least one fluid channel to absorb contaminants on the polishing surface via the plurality of vacuum holes;
• and
• a washing solution supply system fluidly connected to the at least one fluid channel, wherein the washing solution supply system is configured to supply a washing solution to flow through the at least one fluid channel and exit the polishing head via the plurality of holes.

A chemical mechanical polishing (CMP) method, comprising:

• pressing a wafer against a polishing surface of a polishing pad with a polishing head during a polishing process, wherein the polishing head comprises a retaining ring configured to retain the wafer and comprising holes adjacent to the polishing surface, and at least one fluid channel inside the polishing head and fluidly connected with the holes;
• drawing contaminants on the polishing surface into the at least one fluid channel through the holes of the polishing head during the polishing process;
• and
• supplying a washing solution into the at least one fluid channel to clean the at least one fluid channel after the polishing process, wherein the washing solution flows out of the at least one fluid channel from the holes of the retaining ring.