Patent ID: 7393705

Claim:
A method for producing gallium nitride light emitting diodes comprising the steps of: (a) growing a gallium nitride epitaxial layer on a top surface of a sapphire substrate; (b) patterning the gallium nitride layer to selectively form a plurality of dies separated by trenches; (c) coating the gallium nitride layer with a phosphor layer that absorbs blue or UV radiation and re-emits radiation to produce a desired spectrum of light, (d) attaching a support structure to the gallium nitride layer with a procedure that includes filling the trenches; (e) irradiating the bottom surface of the sapphire substrate with a plurality of pulses of laser radiation having a wavelength that is substantially absorbed by the gallium nitride near the interface of the gallium nitride layer and the sapphire substrate, wherein the laser radiation is patterned so that (i) the laser radiation reaches areas where the gallium nitride and sapphire substrate interface and does not reach the filled trenches, whereby the gallium nitride and sapphire delaminate to create an exposed gallium nitride layer, (ii) the laser radiation is shaped to prevent partial irradiation of a die; and (iii) the pulses of laser radiation are moved across the gallium nitride layer in a manner that avoids substantial overlap of pulses of laser radiation; and (f) removing the sapphire substrate.