LED wafer with laminated phosphor layer
First Claim
1. A method for fabricating a light emitting diode (LED) device comprising:
- growing LED layers on a growth substrate;
providing a preformed phosphor sheet separate from the LED layers;
affixing the LED layers to a carrier substrate using a releasable adhesive;
removing the growth substrate while the carrier substrate provides mechanical support for the LED layers;
laminating the preformed phosphor sheet to an exposed surface of the LED layers;
dicing the phosphor sheet and the LED layers to create separate LED dice, each having an overlying phosphor layer;
releasing the LED layers from the releasable adhesive; and
removing the LED dice from the carrier substrate.
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Accused Products
Abstract
An LED wafer with a growth substrate is attached to a carrier substrate by, for example, a heat-releasable adhesive so that the LED layers are sandwiched between the two substrates. The growth substrate is then removed, such as by laser lift-off. The exposed surface of the LED layers is then etched to improve light extraction. A preformed phosphor sheet, matched to the LEDs, is then affixed to the exposed LED layer. The phosphor sheet, LED layers, and, optionally, the carrier substrate are then diced to separate the LEDs. The LED dice are released from the carrier substrate by heat or other means, and the individual LED dice are mounted on a submount wafer using a pick-and-place machine. The submount wafer is then diced to produce individual LEDs. The active layer may generate blue light, and the blue light and phosphor light may generate white light having a predefined white point.
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Citations
15 Claims
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1. A method for fabricating a light emitting diode (LED) device comprising:
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growing LED layers on a growth substrate; providing a preformed phosphor sheet separate from the LED layers; affixing the LED layers to a carrier substrate using a releasable adhesive; removing the growth substrate while the carrier substrate provides mechanical support for the LED layers; laminating the preformed phosphor sheet to an exposed surface of the LED layers; dicing the phosphor sheet and the LED layers to create separate LED dice, each having an overlying phosphor layer; releasing the LED layers from the releasable adhesive; and removing the LED dice from the carrier substrate. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
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13. A light emitting diode (LED) structure comprising:
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an LED wafer, including a growth substrate, the LED wafer having a first surface; a carrier substrate affixed to the first surface by a releasable adhesive, wherein the growth substrate is removed from the LED wafer, the LED wafer having a second surface opposite to the first surface; and a preformed phosphor sheet, formed separate from the LED wafer, affixed to the second surface of the LED wafer, wherein the phosphor sheet and LED wafer are not yet diced. - View Dependent Claims (14, 15)
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Specification