Patent ID: 7700413

Claim:
A production method of a compound semiconductor light-emitting device wafer comprising a step of forming trenches in separation zones of the top surface (i.e., surface on a semiconductor side) of a compound semiconductor light-emitting device wafer including a substrate and numerous compound semiconductor light-emitting devices, the devices being regularly and periodically arranged with the separation zones being disposed therebetween; a step of polishing the back surface of the substrate so as to have a surface coarseness Ra (arithmetic mean coarseness) of 0.001 μm to 2 μm; a step of forming a protective film on the top surface of the wafer; a step of forming separation grooves having a width less than a width of the trench by means of laser processing in the separation zones of the surface on which the protective film is formed, while a gas is blown onto a laser-irradiated portion; and a step of removing at least a portion of the protective film, which steps are performed in the above sequence.