Insight on Surface Changes Post Chemical Mechanical Polishing (CMP) of the Silicon Substrate by Adding Polyoxyethylene Ether

Abstract

Fatty alcohol polyoxyethylene ether (AEO-9) and isomeric decyl polyoxyethylene ether (XP-70, XP-90) were tested as additives to the slurries aiming at improving surface quality during Si fine chemical mechanical polishing (CMP) in 14 nm ultra-large-scale integration. Based on large particle count, contact angles analyzer, and polishing data, it was revealed that XP-90 exhibits improved dispersibility and hydrophilicity, reducing roughness and defects. Various analytical results on silicon surfaces including X-ray photoelectron spectrometer, Fourier transform infrared spectrometer, and scanning electron microscope data shed new light on the mechanism of polyoxyethylene ether in silicon CMP. And the surface roughness of Si is optimized as well.

Effect of Polyoxyethylene-Based Nonionic Surfactants on Chemical–Mechanical Polishing Performance of Monocrystalline Silicon Wafers

“…Specifically, the addition of AEO-9 reduces the surface roughness of wafers by over 60%. In addition to its molecular structure, the activity of a surfactant is also dependent on its hydrophilic-lipophilic balance (HLB) value [24]. In terms of HLB values, PEG > TPEG > OP-9 > AEO-9.…”

“…In terms of HLB values, PEG > TPEG > OP-9 > AEO-9. Studies have shown that the lower the HLB value, the greater the likelihood of micelle formation and the higher the surface tension [24,25]. The polishing performance of monocrystalline silicon wafers was affected differently by these.…”