Study on Chemical Mechanical Polishing of GeSbTe for Chalcogenide Phase Change Memory

Chalcogenide phase change memory (C-PCM) is one kind of quickly developing non-volatile memory devices. In this paper, chemical mechanical polishing of GeSbTe, the key materials for C-PCM, was performed by the polisher with on-line mechanics sensor. The CMP process control and the formation of fill array structure of GST with the polishing slurry made of colloidal silica abrasives were investigated. Results show that the coefficient of friction clear changes at the interface of SiO₂ and GST, which can efficiently on-line control the CMP process. In addition, results of AFM show that the RMS of roughness has been reduced from 2.218nm to 0.8288nm. SEM and EDS results show that the array fill structure of GST has been achieved by controlled-CMP of GST and the element composition in the hole was not changed. In sum, the CMP process control of GST and the array fill structure of GST in SiO₂ dielectric was achieved with the colloidal silica slurry self-made