Light emitting element and method of making the same

• US 20100012968A1
• Filed: 07/09/2009
• Published: 01/21/2010
• 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
• Granted Patent: US 8,124,999 B2
• Time in Patent Office: Days
• 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 light emitting element, comprising:

a first electrode;

a second electrode formed on a same side as the first electrode and comprising 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 comprising a level at a top thereof higher than that of the first bump.

2. The light emitting element according to claim 1, wherein

the second electrode comprises a concave portion on an upper surface thereof for receiving a melt of the second bump.

3. The light emitting element according to claim 1, further comprising:

group III nitride semiconductor layers including an n-type contact layer, an n-type cladding layer, a light-emitting layer, a p-type cladding layer and a p-type contact layer,

wherein the first electrode is formed on the p-type contact layer, and

the second electrode is formed on the n-type contact layer.

4. A method of making a light emitting element, comprising:

growing, on a growth substrate, group III nitride semiconductor layers including an n-type contact layer, an n-type cladding layer, a light-emitting layer, a p-type cladding layer and a p-type contact layer;

removing a part of the p-type contact layer, the p-type cladding layer, the light-emitting layer, and the n-type cladding layer to expose the n-type contact layer;

forming a p-side electrode on the p-type contact layer;

forming an n-side electrode on the n-type contact layer, the n-side electrode comprising an area less than that of the p-side electrode;

forming a p-side bump on the p-side electrode; and

forming an n-side bump on the n-side electrode, the n-side bump comprising a level at a top thereof higher than that of the p-side bump.

5. The method according to claim 4, further comprising:

forming a concave portion on an upper surface of the n-side electrode for receiving a melt of the n-side bump.

6. 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

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 from one of the plurality of intermediate electrodes to an edge of the extended part.

7. The flip-chip type light emitting element according to claim 6, 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.

8. The flip-chip type light emitting element according to claim 7, 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.