In a method for mathematically characterizing a multizone CMP carrier, alternating zones are pressurized to a first pressure and the remaining zones are pressurized to a second lower pressure. A first wafer may then be polished using this combination of pressures and a first material removal profile...http://www.google.se/patents/US6468131?utm_source=gb-gplus-sharePatent US6468131 - Method to mathematically characterize a multizone carrier
