Double substrate multi-junction light emitting diode array structure
View Patent ↗The present disclosure provides one embodiment of a light-emitting structure. The light-emitting structure includes a carrier substrate having first metal features; a transparent substrate having second metal features; a plurality of light-emitting diodes (LEDs) bonded with the carrier substrate and the transparent substrate, sandwiched between the carrier substrate and the transparent substrate; and metal pillars bonded to the carrier substrate and the transparent substrate, each of the metal pillars being disposed between adjacent two of the plurality of LEDs, wherein the first metal features, the second metal features and the metal pillars are configured to electrically connect the plurality of LEDs.
1. A method comprising:
forming light-emitting diodes (LEDs) on a first substrate;
forming metal pillars on the first substrate, wherein each of the metal pillars is interposed between two adjacent LEDs;
bonding a second substrate to the LEDs;
removing the first substrate; and
bonding a transparent substrate to the LEDs, such that the LEDs are sandwiched between the second substrate and the transparent substrate.
2. The method of claim 1 , wherein the forming of the LEDs includes:
growing epitaxy layers having:
an n-type doped semiconductor layer;
a multi-quantum well (MQW); and
an n-type doped semiconductor layer; and
patterning the epitaxy layers to form the LEDs.
3. The method of claim 1 , further comprising scribing the first substrate.
4. The method of claim 1 , wherein the forming of the metal pillars includes:
forming a patterned seed layer on the first substrate; and
thereafter performing a plating process to the patterned seed layer, thereby forming the metal pillars.
5. The method of claim 1 , wherein:
the first substrate is a sapphire substrate;
the second substrate is a silicon substrate; and
the transparent substrate is a glass substrate.
6. The method of claim 1 , further comprising:
forming first metal features on the second substrate; and
forming second metal features on the transparent substrate such that the first metal features, the second metal features, and the metal pillars are configured to electrically connect at least a subset of the LEDs in series.
7. The method of claim 1 , further comprising disposing a luminescent material in one of a configuration:
on an outer surface of the transparent substrate;
between the transparent substrate and the LEDs; and
in the transparent substrate.
8. The method of claim 1 , wherein the bonding of the second substrate and bonding of the transparent substrate utilize eutectic bonding.
9. The method of claim 1 , further comprising creating a rough surface to the transparent substrate by a process selected from the group consisting of polishing, etching, and a combination thereof.
10. A method comprising:
bonding a plurality of light-emitting diodes (LEDs) on a silicon substrate; and
bonding a transparent substrate to the plurality of LEDs such that the plurality of LEDs are sandwiched in the silicon substrate and the transparent substrate, wherein the silicon substrate and the transparent substrate further include first metal features and second metal features, respectively, to electrically connect the plurality of LEDs.
11. The method of claim 10 , wherein the bonding of the plurality of LEDs includes:
forming epitaxy semiconductor layers on a sapphire substrate;
patterning the epitaxy semiconductor layers to form the plurality of LEDs on the sapphire substrate; and
bonding the plurality of LEDs with the sapphire substrate to the silicon substrate.
12. The method of claim 11 , further comprising forming metal pillars on the sapphire substrate such that the first metal features, the metal features, and the metal pillars are configured to electrically couple at least a subset of the plurality of LEDs in series, after the patterning of the epitaxy semiconductor layers.
13. A method, comprising:
forming a plurality of light-emitting diodes (LEDs) on a sapphire substrate;
forming a plurality of metal components over the sapphire substrate, wherein the metal components interleave with the LEDs;
bonding a silicon substrate to the LEDs;
removing the sapphire substrate; and
bonding a transparent substrate to the LEDs, such that the transparent substrate and the silicon substrate are bonded on opposite sides of the LEDs.
14. The method of claim 13 , further comprising performing a scribing process to the sapphire substrate.
15. The method of claim 13 , wherein the forming of the metal components comprises forming a plurality of metal pillars as the metal components.
16. The method of claim 15 , wherein the metal pillars are formed such that top surfaces of the metal pillars are substantially co-planar with top surfaces of the LEDs.
17. The method of claim 13 , wherein each metal component is formed between two respective adjacent LEDs.
18. The method of claim 13 , wherein the metal components are formed to provide electrical interconnection paths for the LEDs.
19. The method of claim 13 , wherein the forming of the metal components comprises:
forming a patterned seed layer on the sapphire substrate; and
thereafter performing a plating process to the patterned seed layer, thereby forming the plurality of metal components.
20. The method of claim 13 , further comprising:
forming a plurality of first metal features on the silicon substrate;
forming a plurality of second metal features on the transparent substrate such that the first metal features, the second metal features, and the metal components are configured to electrically connect at least a subset of the LEDs in series; and
roughening a surface of the transparent substrate.
21. The method of claim 13 , wherein at least one of the bonding of the silicon substrate and the bonding of the transparent substrate comprises eutectic bonding.