High-efficiency light extraction structures and methods for solid-state lighting
First Claim
1. A light emitting apparatus comprising:
- a semiconductor structure comprising a light emitting diode, said structure having recesses therein;
a carrier that has a thermal conductivity that is higher than that of the structure and/or a CTE where there is a substantial mismatch between CTE of the structure and that of said carrier; and
a stress-absorbing material attaching the structure to the carrier, said material substantially filling said recesses.
1 Assignment
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Accused Products
Abstract
A soft solder flowing into the recesses of a semiconductor thin film LED provides: (a) increased bonding strength and better mechanical durability, (b) improved heat dissipation, (c) enhanced light extraction when the LED film is bonded to a new carrier. Annealing localized islands of absorbing metal creates an ohmic contact. Those isolated islands are inter-connected by a layer of a highly reflective metal. This design enables a significant absorption reduction within the LED device and leads to a significant improvement of light extraction. Additionally, the light extraction efficiency of an isotropic light emitting device is improved via surface shaping of the device by a 2D-array of micro-lenses and photonic band gap structure. For manufacturability purpose the making of micron-size lenses of the surface of the chip may preferably be performed as a final step, preferably with optical lithography.
102 Citations
37 Claims
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1. A light emitting apparatus comprising:
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a semiconductor structure comprising a light emitting diode, said structure having recesses therein;
a carrier that has a thermal conductivity that is higher than that of the structure and/or a CTE where there is a substantial mismatch between CTE of the structure and that of said carrier; and
a stress-absorbing material attaching the structure to the carrier, said material substantially filling said recesses. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22)
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23. A light emitting apparatus comprising:
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a semiconductor structure comprising a light emitting diode; and
an electrically conductive network for applying a current to the structure to cause the diode to emit light, said network comprising;
an array of metal contacts wherein each of at least some of the contacts is not in contact with any other contact in the array, and wherein the contacts form ohmic contacts with the semiconductor structure; and
an electrically conductive material connecting the contacts, said material being light reflective or substantially transparent with respect to light emitted by the diode. - View Dependent Claims (24, 25, 26, 27)
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28. A method for making a light emitting apparatus comprising:
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providing a semiconductor structure comprising a light emitting diode, said structure having recesses therein; and
attaching to the structure a carrier having a thermal conductivity that is higher than that of the structure and/or a CTE where there is a substantial mismatch between CTE of the structure and that of said carrier by means of a stress-absorbing material so that said material substantially fills said recesses. - View Dependent Claims (29, 30, 31, 32, 33, 34, 35)
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36. A method for attaching a semiconductor wafer to a carrier, comprising:
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bringing the semiconductor wafer and the carrier into contact in a vacuum environment; and
applying uniform pressure and temperature to the semiconductor wafer and the carrier to create a strong and uniform bonding therebetween, wherein the pressure is unidirectional or isostatic. - View Dependent Claims (37)
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Specification