Effect of Neotame and pH on LiTaO₃ Chemical Mechanical Polishing

Abstract

LiTaO3 has piezoelectric, ferroelectric, and pyroelectric optical properties with a broad transparent range from ultraviolet to infrared. In order to ensure good performance of the LiTaO3 substrate, the surface of the LiTaO3 substrate must be smooth. Chemical mechanical polishing has been used for planarization of integrated circuits or to obtain substrates of high surface quality. In this paper, neotame was studied as an additive for LiTaO3 slurry, which plays an important role in the polishing process. In addition, we show that different pH and different concentrations of neotame have a strong influence on the polishing rate, the surface roughness of the LiTaO3 substrate after polishing is different, and the surface roughness of the LiTaO3 substrate can be reduced to 0.112 nm. More importantly, neotame could improve the work-life of the polishing slurry and reduce the coefficient of friction, thereby reducing the fragmentation rate. Finally, the possible chemical reaction mechanism of neotame to accelerate polishing efficiency was given.

Kinetic Modeling and Material Removal Mechanism Analysis of Fixed-Abrasive Polishing for Lithium Tantalite Wafer

“…12 Free-abrasive lapping and then chemical mechanical polishing (CMP) 13 is now the main method to produce LT wafers with ultraprecision smooth surface, and in the processing the mechanical action and the chemical reaction between the polishing liquid and workpiece are both conducive to the removal of LT and reduction of the surface damage of workpiece. 14 Lee used KOH-H 2 O 2 acidassisted CMP polishing liquid to polish the LT wafer for 10 min, with the R a reduced from 141 nm before processing to 1.71 Å 15 ; Xia et al 16 used natural garnet abrasives and CMP to polish LT wafers, and obtained Y-36°LT wafers with higher surface quality under certain conditions; Wei et al 17 used asphalt polishing pads and flat flannel polishing pads for rough polishing, and non-woven fabrics for fine polishing. When the polishing disk rotated at 60 rpm and the pH of the polishing liquid was 10, the surface roughness of LT was less than 5 nm after 60 min, but with poor workpiece surface accuracy and low processing efficiency.…”