Processing characteristics of ultrathin SrTiO3 ceramic substrates

To solve the fracture problem of ultrathin, soft-brittle and large warp SrTiO3 ceramic substrates, a new anti-broken two-sided lapping method was proposed. With this new method, the materials at the convex peak of the substrate surface which thinnest thickness is only 0.19 mm but warp up to 0.6 mm were removed firstly. Then more and more materials were removed and a flat SrTiO3 substrate without broken was obtained ultimately. The main material removal method of SrTiO3 substrate was the fracture of the crystallites rolled by abrasive, while some crystallites were pulled out. As the material was removed, the substrate surface became higher density. Using 1.5 μm Al2O3 slurry, a surface with Ra 0.0285 μm was obtained by using this method. An ultra-smooth surface with Ra 0.0038 m was achieved by cluster magnetorheological polishing, the grain boundary and coarse grain structure on the surface could be seen clearly.