Development of a new drum-type line contact CMP machine

A new line contact polishing machine, developed as a next-generation CMP (chemical mechanical polishing) machine, provides more precise settings of the polishing conditions than the conventional surface contact-type polishing machine, yielding high prospects of realising uniform polishing. Recognising the importance of the relative speed and staying time of the rotating drum at given positions over the wafer, the profiles of the wafer surfaces polished by the prototype machine devised for this research were investigated. As a result, actually polished surface profiles produced almost identical results with the theoretical profiles obtained by taking the staying time of the rotating drum in contact with the wafer and its relative speed into consideration. This result proves that under the uniform linear contact status, uniform polishing is fully achievable if suitable polishing conditions are established.