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 R_a.

• Periodical: Advanced Materials Research (Volume 1136)
• Pages: 305-310
• DOI: https://doi.org/10.4028/www.scientific.net/AMR.1136.305
• Online since: January 2016
• Authors: Hyun Seop Lee*
• Keywords: Additive, Chemical Mechanical Polishing (CMP), Citric Acid, Lithium Tantalate (LiTaO₃), Surface Roughness

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