An investigation into chemical-mechanical polishing process of zinc selenide

An analysis of chemical-mechanical polishing (CMP) under fixed polishing conditions and different polishing times has been performed on ZnSe single crystals. The morphology of finishing surface was monitored by atomic force microscopy (AFM) and differential interference contrast (DIC) optical microscopy. Novel X-ray diffraction techniques such as grazing incidence X-ray diffraction (GIXD), asymmetric inclined plane X-ray diffraction (AIPXD), and symmetric inclined plane X-ray diffraction (SIPXD) were employed to study the surface and subsurface structural damages in ZnSe after polishing. Surface chemical analysis was carried out utilizing X-ray photoelectron spectroscopy (XPS) for polished ZnSe samples. Consistent improvement of surface and subsurface structure as well as surface morphology with increased polishing time was noticed. A large number of Se nanoprecipitates were observed appearing on ZnSe surface after CMP.; A statistical CMP model based on Yates' algorithm was developed in this study. This model was used to systematically investigate the effects of specific polishing variables on the sodium hypochlorite (NaOCl) based CMP process of ZnSe. The force applied on the samples and the NaOCl concentration in the polishing slurry were found to be the most critical individual polishing parameters. In addition, maintaining an appropriate balance between the mechanical polishing component and the chemical etching component in the CMP process was found to be a crucial factor in determining the surface quality of polished ZnSe samples.