Novel electrolysis-ionized-water cleaning technique for the chemical-mechanical polishing (CMP) process

Recently, chemical-mechanical-polishing (CMP) technology has become more and more important as device packing-density has increased. This is because the CMP of interlayer dielectrics realizes global planarization resulting in multi-level interconnections with finer pitches. However, effective wafer surface cleaning for particles and contamination is needed because slurries with colloidal silica particles are used during the CMP processing. Though wafer cleaning by using acid or alkaline chemicals was generally used, an increasing amount of the chemicals will cause ecological problems. We have reported that the electrolysis ionized water cleaning technique was useful for the removal of particles and metal contamination. This indicates a ecologically-safe cleaning process without using direct chemical reactions. This paper presents a reductive electrolysis ionized water cleaning technique for application to CMP processes, which includes a spin rinser system. Damage-free cleaning for an Al damascene process after the CMP is demonstrated for the first time.<>