Light emitting element and method of making the same

• US 8,124,999 B2
• Filed: 07/09/2009
• Issued: 02/28/2012
• Est. Priority Date: 07/18/2008
• Status: Active Grant

• Current Assignee: Toyoda Gosei Company Limited (Toyota Motor Corporation)
• Original Assignee: Toyoda Gosei Company Limited (Toyota Motor Corporation)
• Inventors: Yahata, Kosuke, Nakajo, Naoki
• Primary Examiner(s): Jackson, Jr., Jerome
• Assistant Examiner(s): Chen, Yu
• Application Number:
  US12/458,362
• Publication Number:
  US 20100012968A1
• Time in Patent Office: 964 Days
• Field of Search: 257/79, 257/99, 257/81, 257/91, 257/745, 257/E33.062, 257/E33.065
• US Class Current: 257/99
• CPC Class Codes: H01L 2224/05001 Internal layers
• CPC Class Codes: H01L 2224/05022 the internal layer being at least partially embedded in the surface
• CPC Class Codes: H01L 2224/05144 Gold [Au] as principal constituent
• CPC Class Codes: H01L 2224/05155 Nickel [Ni] as principal constituent
• CPC Class Codes: H01L 2224/05164 Palladium [Pd] as principal constituent
• CPC Class Codes: H01L 2224/05166 Titanium [Ti] as principal constituent
• CPC Class Codes: H01L 2224/05169 Platinum [Pt] as principal constituent
• CPC Class Codes: H01L 2224/05548 Bonding area integrally formed with a redistribution layer on the semiconductor or solid-state body
• CPC Class Codes: H01L 2224/0557 the external layer being disposed on a via connection of the semiconductor or solid-state body
• CPC Class Codes: H01L 2224/05571 the external layer being disposed in a recess of the surface
• CPC Class Codes: H01L 2224/05624 Aluminium [Al] as principal constituent
• CPC Class Codes: H01L 2224/0603 Bonding areas having different sizes, e.g. different heights or widths
• CPC Class Codes: H01L 2224/06051 Bonding areas having different shapes
• CPC Class Codes: H01L 2224/06102 the bonding areas being at different heights
• CPC Class Codes: H01L 2224/16 of an individual bump connector
• CPC Class Codes: H01L 24/05 of an individual bonding area
• CPC Class Codes: H01L 24/06 of a plurality of bonding areas
• CPC Class Codes: H01L 24/14 of a plurality of bump connectors
• 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 33/44 characterised by the coatings, e.g. passivation layer or anti-reflective coating
• CPC Class Codes: H01L 33/58 : Optical field-shaping elements
• 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 element includes a first electrode, a second electrode formed on a same side as the first electrode and including an area less than the first electrode, a first bump formed on the first electrode, and a second bump formed on the second electrode and including a level at a top thereof higher than that of the first bump. A flip-chip type light emitting element includes a spreading electrode, the spreading electrode including an extended part, and plural intermediate electrodes formed on the spreading electrode and arranged in a longitudinal direction of the extended part and centrally in a width direction of the extended part. The intermediate electrodes are disposed such that a distance of half a pitch thereof in the longitudinal direction is equal to or shorter than a distance from one of the intermediate electrodes to an edge of the extended part.

Claims

1. A flip-chip type light emitting element, comprising:

a spreading electrode for feeding current to a light-emitting layer, the spreading electrode comprising an extended part extending in a predetermined direction;

a plurality of intermediate electrodes formed on the spreading electrode and arranged in a longitudinal direction of the extended part and centrally in a width direction of the extended part;

an insulating layer formed on the spreading electrode and on the plurality of intermediate electrodes; and

a joining electrode formed on the insulating layer for feeding current through the plurality of intermediate electrodes to the spreading electrode,

wherein the plurality of intermediate electrodes are disposed such that a distance of half a pitch thereof in the longitudinal direction is equal to or shorter than a distance measured in the width direction from one of the plurality of intermediate electrodes to an edge of the extended part.

2. The flip-chip type light emitting element according to claim 1, wherein the spreading electrode is shaped like teeth of a comb in a top view, wherein a plurality of the extended parts are arranged in the width direction.

3. The flip-chip type light emitting element according to claim 2, wherein the plurality of intermediate electrodes are each shaped like a circle in a top view with a diameter of not less than 20 μ

m and less than 80 μ

m.

4. The flip-chip type light emitting element according to claim 1, wherein the insulating layer abuts the plurality of intermediate electrodes.

5. The flip-chip type light emitting element according to claim 1, wherein the joining electrode is disposed on an upper surface of the plurality of intermediate electrodes.

6. The flip-chip type light emitting element according to claim 1, wherein the joining electrode abuts an upper surface of each of the plurality of intermediate electrodes.

7. The flip-chip type light emitting element according to claim 1, wherein a lower surface of the joining electrode abuts an upper surface of one of the plurality of intermediate electrodes.

8. The flip-chip type light emitting element according to claim 1, wherein the joining electrode is a different layer from a layer of the plurality of intermediate electrodes.

9. The flip-chip type light emitting element according to claim 1, further comprising a reflection portion disposed in the insulating layer.

10. The flip-chip type light emitting element according to claim 9, wherein the insulating layer is disposed between the spreading electrode and the reflection portion.

11. The flip-chip type light emitting element according to claim 1, wherein the pitch is defined as a distance between centers of adjacent intermediate electrodes, and said distance to the edge of the extended part is defined as a distance from a center of said one of the plurality of intermediate electrode to the edge of the extended part.

12. The flip-chip type light emitting element according to claim 1, further comprising:

another joining electrode formed on corners of the joining electrode on the light emitting element.

13. The flip-chip type light emitting element according to claim 12, further comprising:

a bump disposed on the joining electrode; and

another bump disposed on said another joining electrode,

wherein an upper surface of said another bump is located higher than the bump.

14. The flip-chip type light emitting element according to claim 12, wherein said another joining electrode comprises a first electrode located on a side of the joining electrode and a second electrode located on another side of the joining electrode.

15. The flip-chip type light emitting element according to claim 14, wherein, in a plan view, said first and second electrodes of said another joining electrode are located above a first section of the plurality of intermediate electrodes and sandwich a second section of the plurality of intermediate electrodes.

16. The flip-chip type light emitting element according to claim 1, wherein the spreading electrode further comprises a transparent electrode.