LiTaO3 기판 초박판화를 위한 화학기계적 연마 슬러리 첨가제에 따른 재료제거 특성 연구 = A Study on the Material Removal Characteristics of Chemical Mechanical Polishing Slurry Additives for Ultra-Thinning of LiTaO3 Substrates

다국어 초록 (Multilingual Abstract)

This study systematically investigates optimal slurry compositions for the chemical mechanical polishing (CMP) of lithium tantalate (LiTaO3) wafers, which are critical for the ultra-thinning processes required in high-performance surface acoustic wave (SAW) filter applications. The research first examines the effect of hydrogen peroxide (H2O2) concentration, employed as an oxidizing agent, on material removal characteristics. The highest material removal rate (MRR) is achieved at 1 wt% H2O2. However, further increases in H2O2 concentration result in a decline in MRR, primarily attributed to the formation of an excessively thick oxide layer. This dense oxide film could not be completely removed by the mechanical abrasion of slurry particles, thereby restricting additional chemical etching and ultimately limiting material removal. Subsequently, a comparative analysis is conducted to evaluate the effects of various chelating agents. Four chelating agents—EDTA, citric acid, oxalic acid, and glycine—are assessed at a consistent concentration, alongside a control condition without a chelating agent. A comprehensive evaluation based on MRR, surface roughness, and post-CMP uniformity identifies oxalic acid as the most effective chelating agent. Its superiority is attributed to promoting a balanced and synergistic interaction between chemical and mechanical processes in the complex polishing environment involving the LiTaO3 surface, H2O2 concentration, and pH. This study further investigates material removal characteristics by systematically varying both H2O2 and oxalic acid concentrations. Based on these findings, an optimized slurry composition for LiTaO3 CMP is proposed to enhance process performance and wafer quality.