In a semiconductor light emitting device, light is lost from a side surface of a substrate; therefore, if a substrate side surface occupies a large area, it decreases light extraction efficiency. The area of the substrate side surface may be reduced by reducing a thickness of the substrate. However, a thin substrate has low mechanical strength and is cracked by a stress during work process, and that decreases the yield.A light emitting layer is formed on a substrate. After fixed to a grinding board with wax, the substrate is ground to thin. A support substrate is then bonded to the substrate for reinforcement. The substrate is fixed to an electrode and others, with the support substrate bonded to the substrate. The support substrate is lastly removed.