Effects of Large Particles on MRR, WIWNU and Surface Quality in TEOS Chemical Mechanical Polishing Based on FA/O Alkaline Slurry

Abstract

Material removal rate (MRR), within-wafer non-uniformity (WIWNU), and root mean square (RMS) roughness are three of the most important factors for chemical mechanical polishing (CMP) in giant-large-scale integrated circuit(GLSI) manufacturing. The effect of large particles on edge MRR, WIWNU and RMS roughness of tetraethylorthosilicate(TEOS) via considering the chemical action was investigated and quantified in this paper. To better understand the effect of large particles on TEOS polishing, four batches of colloidal silica with different large particle count (LPC) were used to formulate slurries. The colloidal silica with higher LPC was filtered and then polishing experiments were carried out using slurry prepared with filtered colloidal silica. Compared with the polishing effect pre and post ultrafiltration, edge MRR, average MRR, WIWNU and RMS roughness were reduced by 57.14%, 34.3%, 77.6%, and 61.8% respectively. Polishing and ultrafiltration experiments demonstrated that when LPC reached 8.6 million parts./ml, edge MRR increased sharply, and WIWNU and RMS roughness were deteriorated. The deterioration mechanism based on FA/O chelating agent was also proposed and discussed in this paper. Such study has certain guiding significance for choosing the colloidal silica produced by ion exchange method to formulate slurries and for ensuring the batch stability of slurry. FA/O chelating agent.