Light emitting diode array on a backplane and method of making thereof

Patent metadata

Field	Value
Publication number	US-10177123-B2
Application number	US-201515533907-A
Country	US
Kind code	B2
Filing date	Dec 17, 2015
Priority date	Dec 19, 2014
Publication date	Jan 8, 2019
Grant date	Jan 8, 2019

Abstract

A backplane optionally having stepped horizontal surfaces and optionally embedding metal interconnect structures is provided. First conductive bonding structures are formed on first stepped horizontal surfaces. First light emitting devices on a first transfer substrate are disposed on the first conductive bonding structures, and a first subset of the first light emitting devices is bonded to the first conductive bonding structures. Laser irradiation can be employed to selectively disconnect the first subset of the first light emitting devices from the first transfer substrate while a second subset of the first light emitting devices remains attached to the first transfer substrate. Additional devices on each additional transfer substrate can be bonded to additional conductive bonding structures on the backplane employing the same method provided that the additional devices are not present in positions that would overlap with pre-existing first light emitting devices or devices on the backplane at a bonding position.

First claim

What is claimed is:

1. An integrated light emitting device assembly comprising first light emitting devices and second light emitting devices bonded to a backplane, wherein:
each first light emitting device emits light at a first wavelength;
each second light emitting device emits light at a second wavelength that is different from the first wavelength;
each first light emitting device is bonded to the backplane through a first stack including a first bonding pad and a first conductive bonding structure;
each second light emitting device is bonded to the backplane through a second stack including a second bonding pad and a second conductive bonding structure; and
a first plane including first interfaces between the first bonding pads and the first conductive bonding structures is vertically offset from a second plane including second interfaces between the second bonding pads and the second conductive bonding structures.

2. The integrated light emitting device assembly of claim 1 , wherein distal surfaces of the first light emitting devices and the second light emitting devices are within a same plane that is spaced from, and is parallel to, the first and second planes.

3. The integrated light emitting device assembly of claim 1 , wherein:
the first bonding pads have a first thickness; and
the second bonding pads have a second thickness that is less than the first thickness.

4. The integrated light emitting device assembly of claim 1 , wherein:
the first bonding pads and the second bonding pads have a same thickness, and are located on stepped surfaces;
bottom surfaces of the first bonding pads are located on a first subset of the stepped surfaces; and
bottom surfaces of the second bonding pads are located on a second subset of the stepped surfaces that are vertically offset from the first subset of the stepped surfaces.

5. The integrated light emitting device assembly of claim 1 , wherein:
the first conductive bonding structures have a first height; and
the second conductive bonding structures have a second height that is less than the first height.

6. The integrated light emitting device assembly of claim 5 , wherein each of the first conductive bonding structures and the second conductive bonding structures has a same volume.

7. The integrated light emitting device assembly of claim 5 , wherein the first conductive bonding structures and the second conductive bonding structures have a same material composition.

8. The integrated light emitting device assembly of claim 5 , wherein:
the first bonding pads have a first thickness;
the second bonding pads have a second thickness; and
a sum of the first thickness and the first height is the same as a sum of the second thickness and the second height.

9. The integrated light emitting device assembly of claim 1 , further comprising third light emitting devices bonded to the backplane, wherein:
each third light emitting device emits light at a third wavelength that is different from the first wavelength and from the second wavelength;
each third light emitting device is bonded to the backplane through a third stack including a third bonding pad and a third conductive bonding structure; and
a third plane including third interfaces between the third bonding pads and the third conductive bonding structures is vertically offset from the first plane and from the second plane.

10. The integrated light emitting device assembly of claim 1 , wherein the first and second light emitting devices are arranged in a periodic array in which center-to-center distances of neighboring light emitting devices along a horizontal direction are integer multiples of a unit distance.

11. An integrated light emitting device assembly comprising first light emitting devices and second light emitting devices bonded to a backplane, wherein:
each first light emitting device emits light at a first wavelength;
each second light emitting device emits light at a second wavelength that is different from the first wavelength;
each first light emitting device is bonded to the backplane through a first stack including a first bonding pad and a first conductive bonding structure;
each second light emitting device is bonded to the backplane through a second stack including a second bonding pad and a second conductive bonding structure; and
the first conductive bonding structures and the second conductive bonding structures have a same height;
each of the first conductive bonding structures has a first volume; and
each of the second conductive bonding structures has a second volume that is less than the first volume.

12. The integrated light emitting device assembly of claim 11 , wherein distal surfaces of the first light emitting devices and the second light emitting devices are within a same plane that is parallel to a top surface of the backplane.

13. The integrated light emitting device assembly of claim 11 , wherein the first bonding pads and the second bonding pads have a same thickness.

14. The integrated light emitting device assembly of claim 13 , wherein bottom surfaces of the first bonding pads and the second bonding pads are located within a same plane including a top surface of the backplane.

15. The integrated light emitting device assembly of claim 11 , wherein the first conductive bonding structures and the second conductive bonding structures have a same material composition.

16. The integrated light emitting device assembly of claim 11 , further comprising third light emitting devices bonded to the backplane, wherein:
each third light emitting device emits light at a third wavelength that is different from the first wavelength and from the second wavelength;
each third light emitting device is bonded to the backplane through a third stack including a third bonding pad and a third conductive bonding structure;
the first conductive bonding structures, the second conductive bonding structures, and the third conductive bonding structures have the same height; and
each of the third conductive bonding structures has a third volume that is less than the second volume.

17. The integrated light emitting device assembly of claim 11 , wherein the first and second light emitting devices are arranged in a periodic array in which center-to-center distances of neighboring light emitting devices along a horizontal direction are integer multiples of a unit distance.

18. An integrated light emitting device assembly comprising:
a backplane having stepped horizontal surfaces at a top side, the stepped horizontal surfaces comprising a first subset of the stepped horizontal surfaces located within a first horizontal surface plane, and a second subset of the stepped horizontal surfaces located within a second horizontal surface plane that is more proximal to a backside surface of the backplane than the first subset of stepped horizontal surfaces is to the backside surface of the backplane;
conductive bonding structures located on the stepped horizontal surfaces of the backplane, the conductive bonding structures comprising first conductive bonding structures overlying the first subset of the stepped horizontal surfaces and second conductive bonding structures overlying the second subset of the stepped horizontal surfaces; and
light emitting devices bonded to the conductive bonding structures, the light emitting devices comprising first light emitting devices that emit light of a first wavelength and overlie the first subset of the stepped horizontal surfaces and second light emitting devices that emit light of a second

Assignees

• Glo Ab

Inventors

• Gardner Nathan
• Kish Jr Fredrick A
• Modric Miljenko
• Pokhriyal Anusha
• Thompson Daniel Bryce
• Danesh Fariba
• Farrens Sharon N

Classifications

• H10P72/7414

  the auxiliary support including means facilitating the selective separation of some of a plurality of devices from the auxiliary support · CPC title

• H10P72/744

  Details of chemical or physical process used for separating the auxiliary support from a device or a wafer · CPC title

• H10P72/74

  using temporarily an auxiliary support · CPC title

• H10W72/07204

  using temporary auxiliary members, e.g. sacrificial coatings · CPC title

• H10W72/252

  comprising solid metals or solid metalloids, e.g. PbSn, Ag or Cu · CPC title