Micro device array for transfer to a receiving substrate

• US 8,558,243 B2
• Filed: 12/07/2012
• Issued: 10/15/2013
• Est. Priority Date: 11/18/2011
• Status: Active Grant

• Current Assignee: Apple Inc.
• Original Assignee: LuxVue Techonology Corporation (Apple Inc.)
• Inventors: Bibl, Andreas, Higginson, John A., Law, Hung-Fai Stephen, Hu, Hsin-Hua
• Primary Examiner(s): Maldonado, Julio J
• Assistant Examiner(s): Singh, Harpreet
• Application Number:
  US13/708,704
• Publication Number:
  US 20130128585A1
• Time in Patent Office: 312 Days
• Field of Search: None
• US Class Current: 257/76
• CPC Class Codes: F21V 7/00 Reflectors for light sources characterised by cooling arrangements F21V29/505
• CPC Class Codes: H01L 2224/95 at chip-level, i.e. with connecting carried out on a plurality of singulated devices, i.e. on diced chips
• CPC Class Codes: H01L 25/0753 the devices being arranged next to each other
• CPC Class Codes: H01L 27/15 including semiconductor components having potential barriers, specially adapted for light emission
• CPC Class Codes: H01L 29/0684 characterised by the shape, relative sizes or dispositions of the semiconductor regions or junctions between the regions
• CPC Class Codes: H01L 33/0093 Wafer bonding; Removal of the growth substrate
• CPC Class Codes: H01L 33/04 with a quantum effect structure or superlattice, e.g. tunnel junction
• CPC Class Codes: H01L 33/06 within the light emitting region, e.g. quantum confinement structure or tunnel barrier
• CPC Class Codes: H01L 33/20 with a particular shape, e.g. curved or truncated substrate
• CPC Class Codes: H01L 33/28 containing only elements of Group II and Group VI of the Periodic Table
• CPC Class Codes: H01L 33/30 containing only elements of Group III and Group V of the Periodic Table

Abstract

A micro light emitting diode (LED) and a method of forming an array of micro LEDs for transfer to a receiving substrate are described. The micro LED structure may include a micro p-n diode and a metallization layer, with the metallization layer between the micro p-n diode and a bonding layer. A conformal dielectric barrier layer may span sidewalls of the micro p-n diode. The micro LED structure and micro LED array may be picked up and transferred to a receiving substrate.

Claims

1. A structure comprising:

a substrate layer;

an array of posts, wherein the array of posts and the substrate layer are integrally formed from a single piece of material comprising a polymer material;

a corresponding array of laterally separate micro devices on the array of posts, wherein each micro device includes a bottom surface that is wider than a corresponding post top surface directly underneath the micro device; and

an array of laterally separate metallization layers between the array of laterally separate micro devices and the array of posts.

2. The structure of claim 1, wherein each of the micro devices are of 1-100 μ

m scale.

3. The structure of claim 1, wherein each micro device includes p-n diode layer comprising:

a p-doped layer;

an n-doped layer; and

a quantum well layer between the p-doped layer and the n-doped layer.

4. The structure of claim 1, wherein each of the posts has a height between 0.2-4 μ

m.

5. The structure of claim 1, further comprising a dielectric layer spanning the bottom surface of each micro device, side surfaces of each post, and a top surface of the substrate layer.

6. The structure of claim 1, wherein each metallization layer includes a bottom surface that is wider than the corresponding post top surface directly underneath the micro device.

7. The structure of claim 6, wherein the bottom surface of each micro device is wider than a top surface of each corresponding metallization layer.

8. The structure of claim 6, wherein each metallization layer makes ohmic contact with each corresponding micro device.

9. The structure of claim 6, wherein each metallization layer is reflective to light emission.

10. The structure of claim 6, wherein each micro device includes p-n diode layer comprising:

a p-doped layer;

an n-doped layer; and

a quantum well layer between the p-doped layer and the n-doped layer.

11. The structure of claim 1, further comprising an array of laterally separate bonding layers between the array of posts and the array of laterally separate metallization layers.

12. The structure of claim 11, wherein array of laterally separate bonding layers is formed of a metal or metal alloy.

13. The structure of claim 12, wherein the array of laterally separate bonding layers is in direct contact with the array of posts and the array of laterally separate metallization layers.

14. The structure of claim 11, wherein the bonding layer has a liquidus temperature such that the bonding layer melts at a temperature without substantially affecting other components of the laterally separate micro devices.

15. The structure of claim 1, further comprising a dielectric layer spanning the bottom surface of each micro device, a bottom surface of the laterally separate metallization layers, side surfaces of each post, and a top surface of the substrate layer.

16. The structure of claim 3, wherein the quantum well layer has a thickness of less than approximately 0.3 μ

m.

17. The structure of claim 3, wherein the p-doped layer has a thickness of approximately 0.1-1 μ

m.

18. The structure of claim 3, wherein the n-doped layer has a thickness of approximately 0.1-6 μ

m.

19. The structure of claim 3, wherein the p-n diode layer has a thickness of less than approximately 9.3 μ

m.

20. The structure of claim 2, comprising millions of laterally separate micro devices on a corresponding millions of posts.

21. The structure of claim 2, comprising hundreds of millions of laterally separate micro devices on a corresponding hundreds of millions of posts.

22. The structure of claim 3, wherein each p-n diode layer comprises a top surface, a bottom surface, and tapered sidewalls.

23. The structure of claim 22, wherein the bottom surface of the p-n diode layer is wider than the top surface of the p-n diode layer.

24. The structure of claim 22, wherein the top surface of the p-n diode layer is wider than the bottom surface of the p-n diode layer.

25. The structure of claim 3, wherein each p-n diode layer comprises a top surface, a bottom surface, and vertical sidewalls.

26. The structure of claim 1, wherein each micro device comprises a micro semiconductor device selected from the group consisting of a diode, transistor, or integrated circuit.

27. The structure of claim 1, wherein each micro device comprises a micro semiconductor device selected from the group consisting of a light emitting diode and laser.

28. The structure of claim 1, wherein the array of posts are formed of a dielectric material.