Sapphire substrate is currently the mainstream substrate used in LEDs. It has the characteristics of good light transmission performance, high temperature resistance, corrosion resistance, low dislocation density, and high product consistency. The sapphire substrate is made of sapphire crystal rods through cutting, grinding, polishing and other processes. The product has excellent indicators. The single-sided polishing roughness is less than 0.2nm, the total thickness deviation (TTV) is less than 5um, the warpage (WARP) is less than 15um, and the crystal orientation deviation is less than ±0.1o.