Study on chemical mechanism of processing silicon by PMMA in water

Abstract

In a previous study, an eco-friendly planarization method for glass and silicon was proposed, utilizing the chemical properties of polymethyl methacrylate (PMMA) in water. Atomically flat, defect-free glass and silicon surfaces were observed using atomic force microscopy, indicating that the underlying processing phenomenon is based on chemical reactions. To date, PMMA remains the only material capable of achieving such surface flattening in water. Understanding the chemical processing mechanism is crucial for improving processing conditions and identifying other suitable polymer materials. In this study, ATR-FTIR spectroscopy and XPS were employed to analyze both the PMMA and the processed silicon surfaces. Based on various observations, we concluded that the O = C–O–C groups on the PMMA surface undergo hydrolysis during processing in water, leading to their rupture. This rupture creates active sites on the PMMA surface, which promote the formation of C–O–Si bonds between the PMMA and the silicon surface, facilitating the removal of silicon atoms.