High planarization process for LiTaO₃ Wafer of oxide single crystal

Abstract

A4-inch Lithium tantalate wafer was fabricated by a grinding process and flatness less than 3µmTTV was achieved. The developed grinding process, which keeps a flat wafer shape and minimizes the crushed layer thickness, could reduce the quantity of material removal and provide better flatness. The grinding wheel showed the coexistence phenomenon of loading and dulling. Therefore, it is important to make a proper selection of a wheel grain and a dressing method.