Particle Reduction in W-CMP Process through Optimizing Post Cleaner

With an advent of sub-20nm device era in semiconductor manufacturing, particle control is becoming challenging in tungsten CMP (Chemical Mechanical Polishing) processes. An additional polishing process called buffing CMP is employed to handle a tight particle control requirement after the tungsten-CMP process, but a monitoring method to confirm the effect of the buffing CMP is also required to be optimized. This paper will introduce the newly optimized monitoring method for the buffing CMP and the results on reduction of particle occurrence by modifying post cleaning processes.