Light emitting device and manufacturing method thereof

• US 10,483,443 B2
• Filed: 03/23/2016
• Issued: 11/19/2019
• Est. Priority Date: 12/02/2013
• Status: Active Grant

• Current Assignee: Nichia Corporation
• Original Assignee: Toshiba Hokuto Electronics Corporation (Toshiba Corporation)
• Inventors: Maki, Keiichi
• Primary Examiner(s): Smith, Zandra V
• Assistant Examiner(s): Stevenson, Andre C
• Application Number:
  US15/078,321
• Publication Number:
  US 20160276561A1
• Time in Patent Office: 1,336 Days
• CPC Class Codes: H01L 2224/14 of a plurality of bump connectors
• CPC Class Codes: H01L 2224/81805 involving forming a eutectic alloy at the bonding interface
• CPC Class Codes: H01L 24/81 using a bump connector
• CPC Class Codes: H01L 25/0753 the devices being arranged next to each other
• CPC Class Codes: H01L 2924/00011 Not relevant to the scope of the group, the symbol of which is combined with the symbol of this group
• CPC Class Codes: H01L 2924/01322 Eutectic Alloys, i.e. obtained by a liquid transforming into two solid phases
• CPC Class Codes: H01L 2933/0033 relating to semiconductor body packages
• CPC Class Codes: H01L 2933/0066 relating to arrangements for conducting electric current to or from the semiconductor body
• CPC Class Codes: H01L 33/52 Encapsulations
• CPC Class Codes: H01L 33/56 Materials, e.g. epoxy or silicone resin
• CPC Class Codes: H01L 33/62 Arrangements for conducting electric current to or from the semiconductor body, e.g. lead-frames, wire-bonds or solder balls

Abstract

A light emitting device includes a first light transmissive supportive substrate having a first light transmissive insulator and a conductive circuitry layer provided on a surface of the first light transmissive insulator, a second light transmissive supportive substrate having a second light transmissive insulator and disposed in such a way that a surface of the second light transmissive insulator faces the conductive circuitry layer and so as to have a predetermined gap from the first light transmissive supportive substrate, a light emitting diode having a main body, and first and second electrodes provided on a surface of the main body and electrically connected to the conductive circuitry layer via a conductive bump, and laid out between the first and second light transmissive supportive substrates, and a third light transmissive insulator embedded in a space between the first light transmissive supportive substrate and the second light transmissive supportive substrate.

Claims

1. A light emitting device comprising:

a first light transmissive supportive substrate that comprises a first light transmissive insulator and a first conductive circuitry layer provided on a surface of the first light transmissive insulator;

a second light transmissive supportive substrate which comprises a second light transmissive insulator, and which is disposed so as to have a predetermined gap from the first light transmissive supportive substrate;

a light emitting diode which comprises a light emitting diode main body, and first and second electrodes, the first electrode electrically connecting the light emitting diode main body to the first conductive circuitry layer via a first conductive bump, the light emitting diode is between the first light transmissive supportive substrate and the second light transmissive supportive substrate; and

a third light transmissive insulator formed in a space between the first light transmissive supportive substrate and the second light transmissive supportive substrate,

wherein the first light transmissive supportive substrate, the second light transmissive supportive substrate and the third light transmissive insulator have flexibility,

a height of the first conductive bump is a height at which the first electrode or a semiconductor layer of the light emitting diode main body does not contact the first conductive circuitry layer when the light emitting device is bent with a radius of 50 mm, and the height of the first conductive bump is in the range of from 5 μ

m to 50 μ

m.

2. The light emitting device according to claim 1, wherein a surface of the second light transmissive insulator faces the first conductive circuitry layer,

the light emitting diode comprises the light emitting diode main body, the first electrode is provided on a surface of the light emitting diode main body and a second electrode is provided on the surface of the light emitting diode main body and is electrically connected to the first conductive circuitry layer via a second conductive bump.

3. The light emitting device according to claim 1, wherein the second light transmissive supportive substrate comprises a second conductive circuitry layer provided on a surface of the second light transmissive insulator, and the second conductive circuitry layer faces the first conductive circuitry layer,

the light emitting diode comprises a light emitting diode main body, the first electrode provided on a surface of the light emitting diode main body and electrically connected to the first conductive circuitry layer via the first conductive bump, and the second electrode provided on an opposite surface of the light emitting diode main body and electrically connected to the second conductive circuitry layer.

4. The light emitting device according to claim 2, wherein a ratio of B/A is in the range of from 0.2 to 0.7, where:

A is a diameter of a surface of the first conductive bump in contact with the first electrode and B is the height of the first conductive bump, or

A is a diameter of a surface of the second conductive bump in contact with the second electrode and B is a height of the second conductive bump.

5. The light emitting device according to claim 2, wherein the second conductive bump has a height of equal to or higher than 5 μ

m and equal to or lower than 50 μ

m.

6. The light emitting device according to claim 2, wherein a contact area between the first conductive bump and the first electrode, and a contact area between the second conductive bump and the second electrode are each equal to or larger than 100 μ

m² and equal to or smaller than 15000 μ

m².

7. The light emitting device according to claim 2, wherein a material of the first conductive bump is any one of the following:

gold;

silver;

copper;

nickel; and

an alloy thereof.

8. The light emitting device according to claim 2, wherein the material of the first conductive bump is any one of the following:

gold;

silver;

copper;

nickel;

an Au-Sn alloy; and

a nickel alloy.

9. The light emitting device according to claim 2, wherein the first conductive bump is a mixture of metal microparticle with a resin.

10. The light emitting device according to claim 2, wherein the first conductive bump has a melting-point temperature of equal to or higher than 180 °

C.

11. The light emitting device according to claim 2, wherein the first conductive bump has a dynamic hardness of equal to or higher than 3 and equal to or lower than 150.

12. The light emitting device according to claim 2, wherein at least one of an upper surface of the first conductive bump and an upper surface of the second conductive is flat.

13. The light emitting device according to claim 2, wherein a ratio between a distance from a surface of the light emitting diode to a top of the first conductive bump, and, a distance from a center of the first conductive bump to a most distant end of the light emitting diode is equal to or larger than 0.120 and equal to or smaller than 0.400.

14. The light emitting device according to claim 2, wherein the first conductive circuitry layer is concaved along the first conductive bump.

15. The light emitting device according to claim 2, wherein the light emitting diode is embedded in the third light transmissive insulator.

16. The light emitting device according to claim 2, wherein the first electrode and the first conductive circuitry layer do not directly contact with each other, but the first conductive bump directly contacts the first conductive circuitry layer.

17. The light emitting device according to claim 1, wherein a contact angle between a first surface of the first electrode and the first conductive bump is equal to or smaller than 135 degrees.

18. The light emitting device according to claim 1, wherein in the first conductive circuitry layer, a portion in contact with the first conductive bump is recessed.

19. The light emitting device according to claim 1, wherein the third light transmissive insulator is filled between the first conductive circuitry layer and the first and second electrodes, and between the first conductive circuitry layer and the semiconductor layer.

20. A flexible light emitting device comprising:

a first light transmissive substrate that comprises a first light transmissive insulator and a conductive layer on the first light transmissive insulator;

a second light transmissive substrate that comprises a second light transmissive insulator, the second light transmissive substrate disposed with a gap from the first light transmissive substrate;

a light emitting diode having a light emitting diode body, and first and second electrodes, the first electrode electrically connecting the light emitting diode body to the conductive layer via a conductive bump, the light emitting diode is located between the first light transmissive substrate and the second light transmissive substrate; and

a third light transmissive insulator formed in a space between the first light transmissive substrate and the second light transmissive substrate, the third light transmissive insulator having a thinner thickness than a height of the light emitting diode;

wherein the first light transmissive substrate in contact with the third light transmissive insulator is formed in a curved shape inwardly from a part where the light emitting diode is laid out and toward a middle portion between an adjoining light emitting diode.

21. The flexible light emitting device according to claim 20, wherein the first light transmissive substrate pushes the conductive layer against the first electrode.

22. The flexible light emitting device according to claim 20,

wherein a height of the conductive bump is equal to or higher than 5 μ

m and equal to or lower than 50 μ

m.

23. The flexible light emitting device according to claim 22,

wherein the height of the conductive bump is equal to or higher than 20 μ

m and

the flexible light emitting device exhibits a light emitting condition is maintained in a flex resistance test, when the flexible light emitting device in a lighting state is wound about a circular cylinder having a 50mm radius.

24. The flexible light emitting device according to claim 20,

wherein the third light transmissive insulator is filled among the conductive layer, a side surface of the conductive bump and an upper surface of the light emitting diode body.

25. The flexible light emitting device according to claim 20,

wherein the conductive layer is concaved along the conductive bump.

26. The flexible light emitting device according to claim 20,

wherein a height of the conductive bump is equal to or higher than 20 μ

m and equal to or lower than 50 μ

m, and

a ratio between a distance from a surface of the light emitting diode to a top of the conductive bump, and, a distance from a center of the conductive bump to a most distant end of the light emitting diode is equal to or larger than 0.12 and equal to or smaller than 0.40.

27. A flexible light emitting device comprising:

a first light transmissive substrate having a first light transmissive insulator and a conductive layer on the first light transmissive insulator;

a second light transmissive substrate having a second light transmissive insulator, disposed with a gap from the first light transmissive substrate;

a light emitting diode having a light emitting diode body, and first and second electrodes, the first electrode electrically connecting the light emitting diode body to the conductive layer via a conductive bump, the light emitting diode is located between the first light transmissive substrate and the second light transmissive substrate; and

a third light transmissive insulator formed in a space between the first light transmissive substrate and the second light transmissive substrate;

wherein a height of the conductive bump is equal to or higher than 20 μ

m and equal to or lower than 50 μ

m, and

a ratio between a distance from a surface of the light emitting diode to a top of the conductive bump, and, a distance from a center of the conductive bump to a most distant end of the light emitting diode is equal to or larger than 0.12 and equal to or smaller than 0.40.

28. The flexible light emitting device according to claim 27,

wherein the height of the conductive bump is equal to or higher than 30 μ

m.

29. The flexible light emitting device according to claim 27,

wherein the flexible light emitting device exhibits a light emitting condition is maintained in a flex resistance test, when the flexible light emitting device in a lighting state is wound about a circular cylinder having a 50 mm radius.

30. The flexible light emitting device according to claim 28,

wherein the flexible light emitting device exhibits a flexural test in terms of a lighting maintaining rate at least 6/6 at a bending radius of 20 mm , when the flexible light emitting device in a lighting state is wound about a circular cylinder a specified bending radius.

31. The flexible light emitting device according to claim 27,

wherein the first light transmissive substrate in contact with the third light transmissive insulator is formed in a curved shape inwardly from a part where the light emitting diode is laid out and toward a middle portion between an adjoining light emitting diode.

32. The flexible light emitting device according to claim 27,

wherein the third light transmissive insulator has a thinner thickness than a height of the light emitting diode.

33. The flexible light emitting device according to claim 31,

wherein the third light transmissive insulator is filled among the conductive layer, a side surface of the conductive bump and an upper surface of the light emitting diode body.

34. The flexible light emitting device according to claim 31,

wherein the conductive layer is concaved along the conductive bump.