Effect of Citric Acid in Chemical Mechanical Polishing (CMP) for Lithium Tantalate (LiTaO₃) Wafer

Abstract

Lithium tantalate (LiTaO3) has piezoelectric, electro-optical and nonlinear optical characteristics, and a wide transparency range going from ultraviolet to infrared. It is desirable that LiTaO3 wafer was a smooth surface in order to function with good quality. Chemical mechanical polishing (CMP) has been used to planarize integrated circuits (ICs) or obtain a high surface quality of the substrates. This paper investigates the effect of citric acid as an additive in the slurry for LiTaO3 CMP. The roughness of the wafers was measured by an atomic force microscopy (AFM, XE-100) after polishing. The slurry, which contains citric acid as an additive, has a higher material removal rate and friction force than a slurry without an additive. After polishing, the surface roughness of the LiTaO3 wafer can be reduced down to 1.7Å of Ra.

Nano Ball‐Milling Using Titania Nanoparticles to Anchor Cesium Lead Bromine Nanocrystals and Energy Transfer Characteristics in TiO2@CsPbBr3 Architecture

“…In view of the character of soft lattice for all‐inorganic halide perovskite NCs, [ 15–18 ] metal oxides nanoparticles (NPs) with high hardness as main media of chemical mechanical polishing (CMP) have been extensively used to smooth the surface of wafers in integrated circuit manufacturing. [ 19–21 ] The surface roughness of wafers acquired by CMP technique approaches 0.3 nm, [ 21 ] which is lower by more than an order of magnitude for most of nanomaterials. Therefore, the metal oxides NPs as “balls” of milling can provide high mechanical energy to interact with the surface atoms of perovskite NCs in the synthetic process of ball‐grinding or ball‐milling.…”

Effect of Neotame and pH on LiTaO3 Chemical Mechanical Polishing

“…The influence of polishing parameters on the CMP process of LiTaO 3 substrate was analyzed in detail. Admirably, Lee 18 estimated that citric acid was added into the KOH-H 2 O 2 based slurry in this experiment as an additive. The result showed the LiTaO 3 removal rate increased from 227.8 nm min −1 to 314.7 nm min −1 as the citric acid concentration in the KOH-H 2 O 2 based slurry was changed from 0 to 0.06 M. However, further addition of citric acid did not increase the LiTaO 3 removal rate.…”