Effect and Mechanism of Dual-Official Group of Ethanolamines on the Chemical Mechanical Polishing of Monocrystalline Silicon

Abstract

Chemical mechanical polishing (CMP) is a key step in semiconductor technology because it is crucial to produce a defect-free and flat enough surface for further processing of microelectronic devices. Silicon (Si) wafer is widely used in integrated circuit (IC) devices, high-density information storage devices, and other advanced applications. In this paper, the effect of different pH and three ethanolamines, such as monoethanolamine (MEA), diethanolamine (DEA), and triethanolamine (TEA), on the removal rate of Si was studied. The influence mechanism of MEA and its concentration on Si removal rate and surface quality were mainly investigated. The results show that the removal rate increased first and then decreased with increasing pH value. Among the three ethanolamines, the effect of the removal rate of Si is MEA > DEA > TEA. It may be related to the denser passivation film formed on the Si surface by increased hydroxyl groups in ethanolamines. The removal rate first increased and then decreased slowly with the concentration of MEA increased. The removal rate reached the peak value (6800 Å·min−1) when the MEA concentration was 0.15 wt%. The changing trend of the removal rate of Si is mainly due to the Si-N bond being generated on the polished Si surface by MEA and the ionization properties of MEA, which are indicated through the X-ray photoelectron spectroscopy (XPS) and the Zeta potential measurements. Meanwhile, Si surfaces with low surface roughness and ultra-smooth with the increase of MEA concentration were obtained.