Micro device with stabilization post
A method and structure for stabilizing an array of micro devices is disclosed. A stabilization layer includes an array of stabilization cavities and array of stabilization posts. Each stabilization cavity includes sidewalls surrounding a stabilization post. The array of micro devices is on the array of stabilization posts. Each micro device in the array of micro devices includes a bottom surface that is wider than a corresponding stabilization post directly underneath the bottom surface.
1. A structure comprising:
a stabilization layer comprising an array of stabilization cavities and an array of stabilization posts, wherein each stabilization cavity includes a stabilization post and sidewalls that surround and are taller than a corresponding stabilization post; and
an array of light emitting diodes (LEDs) on the array of stabilization posts;
wherein each LED in the array of LEDs includes a bottom surface that is wider than a corresponding stabilization post directly underneath the bottom surface.
2. The structure of claim 1 , further comprising a sacrificial layer between the stabilization layer and the array of LEDs, wherein the array of stabilization posts extend through a thickness of the sacrificial layer, and wherein the sacrificial layer spans along a side surface of each of the LEDs in the array of LEDs, the side surface running between a top surface and the bottom surface of each LED in the array.
3. The structure of claim 2 , wherein the sacrificial layer comprises an oxide or nitride.
4. The structure of claim 1 , further comprising an array of bottom conductive contacts on the bottom surfaces of the array of LEDs.
5. The structure of claim 4 , wherein each stabilization post includes a top surface contact area that is less than a bottom surface contact area of a corresponding bottom conductive contact.
6. The structure of claim 4 , wherein each stabilization post top surface is characterized by a length and a width.
7. The structure of claim 4 , wherein each stabilization post top surface is characterized by an equal length and width.
8. The structure of claim 4 , wherein each bottom conductive contact comprises a layer stack.
9. The structure of claim 8 , wherein the layer stack comprises:
an electrode layer;
a mirror layer on the electrode layer;
a barrier layer on the mirror layer;
a diffusion barrier layer on the barrier layer; and
a bonding layer on the diffusion barrier layer.
10. The structure of claim 8 , wherein the layer stack comprises:
an electrode layer comprising nickel;
a mirror layer comprising silver on the electrode layer;
a barrier layer comprising titanium on the mirror layer;
a diffusion barrier layer comprising platinum on the barrier layer; and
a bonding layer comprising a noble metal on the diffusion barrier layer.
11. The structure of claim 8 , wherein the layer stack comprises a bonding layer, and the bonding layer comprises a noble metal.
12. The structure of claim 11 , wherein the stabilization layer is formed of a thermoset material.
13. The structure of claim 12 , wherein the thermoset material comprises benzocyclobutene (BCB), and the noble metal is gold.
14. The structure of claim 8 , wherein the layer stack further comprises:
an electrode layer on the bottom surface of the LED; and
a diffusion barrier layer on and around sidewalls the electrode layer;
wherein the bonding layer is on the diffusion barrier layer.
15. The structure of claim 14 , wherein the stabilization layer is formed of a thermoset material, and the bonding layer comprises a noble metal.
16. The structure of claim 1 , wherein the stabilization posts in the array of stabilization posts are separated by a pitch of 1 μm to 100 μm.
17. The structure of claim 1 , wherein the stabilization posts in the array of stabilization posts are separated by a pitch of 1 μm to 10 μm.
18. The structure of claim 1 , wherein each LED includes a top surface that is above a corresponding staging cavity sidewalls top surface.