Method of fabricating light emitting diode using laser lift-off technique and laser lift-off apparatus having heater
View Patent ↗An approach is provided for fabricating a light emitting diode using a laser lift-off apparatus. The approach includes growing an epitaxial layer including a first conductive-type compound semiconductor layer, an active layer and a second conductive-type compound semiconductor layer on a first substrate, bonding a second substrate, having a different thermal expansion coefficient from that of the first substrate, to the epitaxial layers at a first temperature of the first substrate higher than a room temperature, and separating the first substrate from the epitaxial layer by irradiating a laser beam through the first substrate at a second temperature of the first substrate higher than the room temperature but not more than the first temperature.
1. A laser lift-off apparatus, comprising:
a laser oscillator to emit a laser beam;
a stage to support a work piece; and
a heater to generate heating to the work piece at 200° C. to lower a bowing degree below about a half of the bowing degree of the work piece at a room temperature, and to generate heating to the work piece over 250° C., wherein the bowing degree is stably maintained about less than a half of the bowing degree of the work piece at the 200° C.
2. The apparatus according to claim 1 , wherein the work piece comprises a first substrate, an epitaxial layer grown on the first substrate, and a second substrate bonded to the epitaxial layer.
3. The apparatus according to claim 2 , wherein the heater is a resistance heater.
4. The apparatus according to claim 3 , wherein the stage comprises a movable main stage and the resistance heater is disposed on the main stage.
5. The apparatus according to claim 4 , wherein the stage further comprises
an insulator provided between the main stage and the resistance heater to shield heat transfer from the resistance heater to the main stage to improve heat efficiency,
a heater securing plate formed on the resistance heater, and
securing pins configured to secure the heater securing plate.
6. The apparatus according to claim 5 , wherein the insulator, the heater securing plate and the securing pins are made of the same material selected from ceramics, plastics or combination of the ceramics and plastics.
7. The apparatus according to claim 5 , wherein the insulator is disposed directly on the stage, and the heater is spaced apart from the stage by the insulator.
8. The apparatus according to claim 7 , wherein the heater is disposed directly on the insulator.
9. The apparatus according to claim 7 , wherein ends of the securing pins are disposed in the insulator.
10. The apparatus according to claim 2 , wherein the heater is one selected from an IR lamp, a heat gun or combinations of the IR lamp and the heat gun.