Light-emitting device and production thereof

• US 20020070449A1
• Filed: 06/11/2001
• Published: 06/13/2002
• Est. Priority Date: 12/21/2000
• Status: Active Grant

• Current Assignee: Lumileds LLC (Apollo Global Management, Inc.)
• Original Assignee: Lumileds Lighting US LLC (Apollo Global Management, Inc.)
• Inventors: Arakane, Fusanori, Tamura, Takeshi, Yagi, Takaaki
• Granted Patent: US 6,642,618 B2
• Time in Patent Office: Days
• 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 PWB (printed wiring board) 101 termed a “chip LED” is used instead of a lead frame. On the substrate is etched a lead 203 buried in the dielectric layer portion. Solder bumps 204 are formed on the PWB. SnPb, In, Au, Ag, or other materials may be used as solder. The gallium nitride semiconductor light-emitting element 102 is arranged this substrate—which includes the electrical wiring—and is connected with the leads thereof. Semiconductor light-emitting element 102 is arranged over bumps 204 and lead connections are made using the bumps, which are masses of metal situated in the electrode portions. Since the fluorescent material is sensitive to temperature, the production process is carried out at low temperature. The temperature is about 80° C. to 150° C. The fluorescent material is admixed into this glass sol-gel solution, which is then applied and heated to produce a glass body. The fluorescent material is a combination of two materials, a blue-excited green fluorescent material and a blue-excited red fluorescent material. The semiconductor element chip is designed for flip-chip bonding. In the process of applying the glass over the surface of the semiconductor chip, flip chip bonding provided better technical affinity, since this connection process does not require the presence of wires. SrS:Eu2+ emits red light, and (Sr, Ba, Ca)S:Eu2+ emits green light. A specific example of a red fluorescent material is SrGd2S4:Eu2.

Claims

1. A light-emitting device wherein a semiconductor light-emitting element flip-chip is electrically interconnected to terminals on a substrate, said device comprising:

a light-emitting element consisting of a gallium nitride semiconductor element; and

a glass layer arranged on the path of the light output by said light-emitting element and containing fluorescent material for receiving said output light and producing converted light converted to a wavelength different from that of said output light;

wherein said emitted light and said converted light are used to produce essentially white 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 the fluorescent material consists of two sulfur-containing compositions, each fluorescent material producing converted light of a different wavelength.

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

Eu2+ that emits red fluorescent light, and the other one is (Sr, Ba, Ca)S;

Eu2+ that emits green fluorescent light.

5. The light-emitting device according to claim 4 wherein the fluorescent material that outputs red fluorescent light is SrGd2S4:

Eu2.

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

m or less.

7. The light-emitting device according to claim 1 wherein said semiconductor light-emitting element is electrically interconnected to terminals on said substrate via a submount.

8. The light-emitting device according to claim 1 wherein said glass layer consists of SiO2 containing at least one compound selected from the group consisting of PbO, Ga2O3, Bi2O3, CdO, ZnO, BaO, and Al2O3;

or of SiO2 substantially devoid thereof.