Micro device stabilization post

• US 8,835,940 B2
• Filed: 09/24/2012
• Issued: 09/16/2014
• Est. Priority Date: 09/24/2012
• Status: Active Grant

• Current Assignee: Apple Inc.
• Original Assignee: LuxVue Techonology Corporation (Apple Inc.)
• Inventors: Hu, Hsin-Hua, Bibl, Andreas, Higginson, John A.
• Primary Examiner(s): Such, Matthew W
• Assistant Examiner(s): STOWE, SCOTT C
• Application Number:
  US13/625,825
• Publication Number:
  US 20140084240A1
• Time in Patent Office: 722 Days
• Field of Search: 257/13, 257/79, 257/88, 257/91, 257/95, 257/98, 257/99, 257/100
• US Class Current: 257/79
• CPC Class Codes: H01L 21/52 Mounting semiconductor bodies in containers
• CPC Class Codes: H01L 21/6835 using temporarily an auxiliary support
• CPC Class Codes: H01L 21/6836 Wafer tapes, e.g. grinding or dicing support tapes adhesive tapes in general C09J7/20
• CPC Class Codes: H01L 2221/6835 used as a support during build up manufacturing of active devices
• CPC Class Codes: H01L 2224/95136 involving guiding structures, e.g. shape matching, spacers or supporting members
• CPC Class Codes: H01L 24/83 using a layer connector
• CPC Class Codes: H01L 24/93 Batch processes
• CPC Class Codes: H01L 24/95 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 25/50 Multistep manufacturing processes of assemblies consisting of devices, each device being of a type provided for in group H01L27/00 or H01L29/00 H01L21/50 takes precedence
• CPC Class Codes: H01L 27/156 two-dimensional arrays
• CPC Class Codes: H01L 2924/00 Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
• CPC Class Codes: H01L 2924/12041 LED
• CPC Class Codes: H01L 2924/12042 LASER
• CPC Class Codes: H01L 2924/1461 MEMS
• CPC Class Codes: H01L 33/0093 Wafer bonding; Removal of the growth substrate
• CPC Class Codes: H01L 33/40 Materials therefor

Abstract

A method and structure for stabilizing an array of micro devices is disclosed. The array of micro devices is formed on an array of stabilization posts formed from a thermoset material. Each micro device includes a bottom surface that is wider than a corresponding stabilization post directly underneath the bottom surface.

Claims

1. A structure comprising:

a stabilization layer comprising an array of stabilization posts, wherein the stabilization layer is formed of a thermoset material;

an array of micro devices supported by the array of stabilization posts;

wherein each micro device includes bottom surface that is wider than a corresponding stabilization post directly underneath the bottom surface; and

a sacrificial layer between the stabilization layer and the array of micro devices, wherein a topography of the stabilization layer beneath the sacrificial layer conforms to the sacrificial layer and the array of stabilization posts extends through a thickness of the sacrificial layer to support the array of micro devices.

2. The structure of claim 1, wherein the thermoset material comprises epoxy.

3. The structure of claim 1, wherein the thermoset material comprises benzocyclobutene (BCB).

4. The structure of claim 1, wherein adjacent stabilization posts in the array of stabilization posts are separated by a pitch of 1 μ

m to 100 μ

m.

5. The structure of claim 1, wherein the stabilization posts in the array of stabilization posts are separated by a pitch of 1 μ

m to 10 μ

m.

6. The structure of claim 1, wherein the sacrificial layer comprises an oxide or nitride.

7. The structure of claim 1, further comprising an adhesion promoter layer between the stabilization layer and the sacrificial layer, wherein the array of stabilization posts extends through a thickness of the adhesion promoter layer.

8. The structure of claim 1, wherein the stabilization posts of the array of stabilization posts are each centered with an x-y center below the micro devices of the array of micro devices.

9. The structure of claim 1, wherein the sacrificial layer spans laterally between the micro devices of the array of micro devices.

10. The structure of claim 1, further comprising an array of bottom conductive contacts on the bottom surfaces of the array of micro devices.

11. The structure of claim 10, further comprising an array of top conductive contacts on top of the array of micro devices.

12. The structure of claim 1, wherein the stabilization layer is bonded to a carrier substrate.

13. The structure of claim 12, further comprising an adhesion promoter layer between the carrier substrate and the stabilization layer.

14. The structure of claim 1, further comprising an etch stop detection layer between the sacrificial layer and the array of micro devices, wherein the array of stabilization posts extends through a thickness of the etch stop detection layer.

15. The structure of claim 14, wherein the etch stop detection layer comprises titanium.

16. The structure of claim 1, wherein the array of micro devices is an array of micro LED devices.

17. The structure of claim 16, wherein each micro LED device includes a device layer comprising:

a p-doped semiconductor layer;

a quantum well layer over the p-doped semiconductor layer; and

an n-doped semiconductor layer.

18. The structure of claim 17, wherein the p-doped layer comprises GaP.

19. The structure of claim 17, wherein the n-doped layer comprises AlGaInP.

20. The structure of claim 17, wherein the quantum well layer comprises multiple quantum well layers.

21. The structure of claim 16, wherein the micro LED devices are designed to emit a red light, and the device layer comprises a material selected from the group consisting of aluminum gallium arsenide (AlGaAs), gallium arsenide phosphide (GaAsP), aluminum gallium indium phosphide (AlGaInP), and gallium phosphide (GaP).

22. The structure of claim 16, wherein the micro LED devices are designed to emit a green light, and the device layer comprises a material selected from the group consisting of indium gallium nitride (InGaN), gallium nitride (GaN), gallium phosphide (GaP), aluminum gallium indium phosphide (AlGaInP), and aluminum gallium phosphide (AlGaP).

23. The structure of claim 16, wherein the micro LED devices are designed to emit a blue light, and the device layer comprises a material selected from the group consisting of gallium nitride (GaN), indium gallium nitride (InGaN), and zinc selenide (ZnSe).

24. The structure of claim 10, wherein the bottom conductive contacts are metallization stacks.

25. The structure of claim 24, wherein the stabilization layer is adhesively bonded to the array of metallization stacks.

26. The structure of claim 25, wherein the metallization stacks comprise a bonding layer comprising a noble metal.

27. The structure of claim 26, wherein the stabilization layer is adhesively bonded to the bonding layer for each metallization stack.

28. The structure of claim 24, wherein the sacrificial layer spans along the bottom surfaces of the array of micro devices and bottom surfaces of the array of bottom conductive contacts.

29. A structure comprising:

a stabilization layer comprising an array of stabilization posts, wherein the stabilization layer is formed of a thermoset material;

an array of micro LED devices on the array of stabilization posts;

wherein each micro LED device includes a device layer comprising;

a p-doped semiconductor layer;

a quantum well layer over the p-doped semiconductor layer;

an n-doped semiconductor layer; and

an ohmic contact layer over the n-doped semiconductor layer; and

wherein each micro LED device includes bottom surface that is wider than a corresponding stabilization post directly underneath the bottom surface.

30. The structure of claim 29, wherein the ohmic contact layer comprises GaAs.

31. The structure of claim 29, further comprising a sacrificial layer between the stabilization layer and the array of micro LED devices, wherein a topography of the stabilization layer beneath the sacrificial layer conforms to the sacrificial layer and the array of stabilization posts extends through a thickness of the sacrificial layer to support the array of micro devices.

32. A structure comprising:

a stabilization layer comprising an array of stabilization posts, wherein the stabilization layer is formed of a thermoset material; and

an array of micro devices on the array of stabilization posts;

wherein each micro device includes bottom surface that is wider than a corresponding stabilization post directly underneath the bottom surface, and the stabilization posts of the array of stabilization posts are each off-centered with an x-y center below the micro devices of the array of micro devices.

33. The structure of claim 32, further comprising a sacrificial layer between the stabilization layer and the array of micro devices, wherein a topography of the stabilization layer beneath the sacrificial layer conforms to the sacrificial layer and the array of stabilization posts extends through a thickness of the sacrificial layer to support the array of micro devices.

34. The structure of claim 32, wherein the thermoset material comprises a material selected from the group consisting of epoxy and benzocyclobutene (BCB).

35. The structure of claim 32, wherein the array of micro devices is an array of micro LED devices.

36. The structure of claim 32, further comprising an array of bottom conductive contacts on the bottom surfaces of the array of micro devices wherein the array of stabilization posts is adhesively bonded to the array of bottom contacts.

37. A structure comprising:

a stabilization layer comprising an array of stabilization posts, wherein the stabilization layer is formed of a thermoset material; and

an array of micro devices on the array of stabilization posts;

wherein each micro device includes bottom surface that is wider than a corresponding stabilization post directly underneath the bottom surface, and each stabilization post spans underneath an edge of two adjacent micro devices.

38. The structure of claim 37, further comprising a sacrificial layer between the stabilization layer and the array of micro devices, wherein a topography of the stabilization layer beneath the sacrificial layer conforms to the sacrificial layer and the array of stabilization posts extends through a thickness of the sacrificial layer to support the array of micro devices.

39. The structure of claim 37, wherein the thermoset material comprises a material selected from the group consisting of epoxy and benzocyclobutene (BCB).

40. The structure of claim 37, wherein the array of micro devices is an array of micro LED devices.

41. The structure of claim 37, further comprising an array of bottom conductive contacts on the bottom surfaces of the array of micro devices wherein the array of stabilization posts is adhesively bonded to the array of bottom contacts.

42. A structure comprising:

a stabilization layer comprising an array of stabilization posts, wherein the stabilization layer is formed of a thermoset material; and

an array of micro devices on the array of stabilization posts;

wherein each micro device includes bottom surface that is wider than a corresponding stabilization post directly underneath the bottom surface, and two stabilization posts are beneath each micro device.

43. The structure of claim 42, further comprising a sacrificial layer between the stabilization layer and the array of micro devices, wherein a topography of the stabilization layer beneath the sacrificial layer conforms to the sacrificial layer and the array of stabilization posts extends through a thickness of the sacrificial layer to support the array of micro devices.

44. The structure of claim 42, wherein the thermoset material comprises a material selected from the group consisting of epoxy and benzocyclobutene (BCB).

45. The structure of claim 42, wherein the array of micro devices is an array of micro LED devices.

46. The structure of claim 42, further comprising an array of bottom conductive contacts on the bottom surfaces of the array of micro devices wherein the array of stabilization posts is adhesively bonded to the array of bottom contacts.