Light-emitting device and production thereof

• US 6,642,618 B2
• Filed: 06/11/2001
• Issued: 11/04/2003
• Est. Priority Date: 12/21/2000
• Status: Expired due to Term

• Current Assignee: Lumileds LLC (Apollo Global Management, Inc.)
• Original Assignee: Lumileds Lighting US LLC (Apollo Global Management, Inc.)
• Inventors: Tamura, Takeshi, Yagi, Takaaki, Arakane, Fusanori
• Primary Examiner(s): Fahmy, Wael
• Assistant Examiner(s): Trinh, (Vikki) Hoa B.
• Application Number:
  US09/879,548
• Publication Number:
  US 20020070449A1
• Time in Patent Office: 876 Days
• Field of Search: 257/734, 257/673, 257/646, 257/676, 257/696, 257/692-693, 257/698, 257/787, 257/794, 257/666, 257/99, 257/688, 257/100
• US Class Current: 257/734
• CPC Class Codes: H01L 2224/0401 Bonding areas specifically adapted for bump connectors, e.g. under bump metallisation [UBM]
• CPC Class Codes: H01L 2224/16 of an individual bump connector
• CPC Class Codes: H01L 2224/48091 Arched
• CPC Class Codes: H01L 2224/48465 the other connecting portion not on the bonding area being a wedge bond, i.e. ball-to-wedge, regular stitch
• 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 2924/00014 the subject-matter covered by the group, the symbol of which is combined with the symbol of this group, being disclosed without further technical details
• CPC Class Codes: H01L 2924/0102 Calcium [Ca]
• CPC Class Codes: H01L 2924/01063 Europium [Eu]
• CPC Class Codes: H01L 2924/01078 Platinum [Pt]
• CPC Class Codes: H01L 2924/01079 Gold [Au]
• CPC Class Codes: H01L 2924/12041 LED
• CPC Class Codes: H01L 33/486 adapted for surface mounting
• CPC Class Codes: H01L 33/501 characterised by the materials, e.g. binder
• 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 comprises a substrate, electrical terminals disposed on a top side of the substrate, and a light-emitting semiconductor device disposed above the substrate. The light-emitting semiconductor device has a bottom side oriented to face toward the top side of the substrate. Electrodes are disposed on the bottom side of the light-emitting semiconductor device and electrically connected to the terminals on the substrate. A glass layer is arranged in a path of output light emitted by the light-emitting semiconductor device. The glass layer contains fluorescent material that converts at least a portion of the output light to converted light having a wavelength different from a wavelength of the output light. The fluorescent material may include SrS:Eu²⁺ that emits red light and (Sr, Ba, Ca)Ga₂S₄:Eu²⁺ that emits green light.

Claims

1. A light-emitting device comprising:

a substrate;

electrical terminals disposed on a surface of said substrate;

a light-emitting semiconductor device disposed above said substrate surface, said of said substrate;

electrodes disposed on said bottom side of said light-emitting semiconductor device and electrically connected to said terminals on said substrate and said light-emitting semiconductor device being electrically connected to said terminals as a flip chip; and

a glass layer arranged in a path of output light emitted by said light-emitting semiconductor device from an obverse top side thereof, said glass layer containing fluorescent material that converts at least a portion of said output light to converted light having a wavelength different from a wavelength of said output light.

2. The light-emitting device according to claim 1 wherein said substrate is a printed board.

3. The light-emitting device according to claim 1 wherein said fluorescent material comprises at least one sulfur-containing composition, each composition producing converted light of a different wavelength.

4. The light-emitting device according to claim 3 wherein one of said compositions comprises SrS:

Eu²⁺ and emits red fluorescent light, and another of said compositions comprises (Sr, Ba, Ca)Ga₂S₄;

Eu²⁺ and emits green fluorescent light.

5. The light-emitting device according to claim 4 wherein said composition that outputs green fluorescent light comprises SrGa₂S₄:

Eu²⁺.

6. The light-emitting device according to claim 1 wherein said glass layer containing said fluorescent material has a thickness of 100 μ

m or less.

7. The light-emitting device according to claim 1 further comprising a submount disposed between said light-emitting semiconductor device and said substrate, wherein said electrodes are electrically connected to said terminals via said submount.

8. The light-emitting device according to claim 1 wherein said glass layer comprises SiO₂.

9. The light emitting device of claim 8 wherein said glass layer further comprises at least one compound selected from the group consisting of PbO, Ga₂O₃, Bi₂O₃, CdO, ZnO, BaO, and Al₂O₃.

10. The light-emitting device of claim 1 wherein said output light and said converted light are used to produce white light.

11. The light-emitting device of claim 1 wherein said light-emitting semiconductor device comprises GaN.

12. The light-emitting device of claim 1 wherein said glass layer has a refractive index greater than about 1.5.

13. The light-emitting device of claim 1 wherein a concentration of said fluorescent material in said glass layer increases with distance from said light-emitting semiconductor device.

14. The light-emitting device of claim 1 wherein said glass layer overlies at least portions of said light-emitting semiconductor device.

15. A light-emitting device comprising:

a light-emitting semiconductor device; and

a hard gel glass layer formed by a sol-gel process, and arranged in a path of output light emitted by said light-emitting semiconductor device, said glass layer containing fluorescent material that converts at least a portion of said output light to converted light having a wavelength different from a wavelength of said output light.

16. The light-emitting device of claim 15, wherein one of said fluorescent materials comprises (Sr, Ba, Ca)Ga₂S₄:

Eu²⁺.

17. The light-emitting device of claim 15 wherein said output light and said converted light are used to produce white light.

18. The light-emitting device of claim 15 wherein said light-emitting semiconductor device comprises GaN.

19. The light emitting device of claim 15 wherein said hard gel glass layer comprises at least one compound selected from the group consisting of PbO, Ga₂O₃, Bi₂O₃, CdO, ZnO, BaO, and Al₂O₃.

20. The light-emitting device of claim 15 wherein said hard gel glass layer overlies at least portions of said light-emitting semiconductor device.