LIGHT EMITTING DEVICE AND METHOD FOR MANUFACTURING THE SAME

• US 20180182929A1
• Filed: 12/14/2017
• Published: 06/28/2018
• Est. Priority Date: 12/28/2016
• Status: Active Grant

• Current Assignee: Nichia Corporation
• Original Assignee: Nichia Corporation
• Inventors: OZEKI, Kenji, GOTO, Akira
• Granted Patent: US 10,243,106 B2
• Time in Patent Office: Days
• CPC Class Codes: H01L 2224/1403 Bump connectors having different sizes, e.g. different diameters, heights or widths
• CPC Class Codes: H01L 2224/1415 Mirror array, i.e. array having only a reflection symmetry, i.e. bilateral symmetry
• CPC Class Codes: H01L 24/11 Manufacturing methods for bumps on insulating substrates H01L21/4853
• CPC Class Codes: H01L 24/14 of a plurality of bump connectors
• CPC Class Codes: H01L 24/17 of a plurality of bump connectors
• CPC Class Codes: H01L 33/005 Processes
• CPC Class Codes: H01L 33/36 characterised by the electrodes
• CPC Class Codes: H01L 33/38 with a particular shape
• CPC Class Codes: H01L 33/382 the electrode extending partially in or entirely through the semiconductor body
• CPC Class Codes: H01L 33/387 with a plurality of electrode regions in direct contact with the semiconductor body and being electrically interconnected by another electrode layer
• CPC Class Codes: H01L 33/486 adapted for surface mounting
• CPC Class Codes: H01L 33/50 Wavelength conversion elements
• CPC Class Codes: H01L 33/52 Encapsulations
• CPC Class Codes: H01L 33/60 Reflective 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 device includes a substrate, a light emitting element, a plurality of bumps and a cover member. The bumps are disposed between the substrate and the light emitting element to mount the light emitting element on the substrate. The bumps include a plurality of first bumps bonded to a first electrode of the light emitting element, and a plurality of second bumps bonded to a second electrode of the light emitting element. The first bumps are spaced apart from exposed portions of a first semiconductor layer of the light emitting element. The first bumps include a plurality of large bumps and a plurality of small bumps each having a smaller surface area than each of the large bumps in a plan view. The cover member covers the light emitting element, the bumps, and the substrate.

Claims

1. A light emitting device comprising:

a substrate having a wiring pattern on an upper face thereof;

a light emitting element mounted on the wiring pattern of the substrate in a flip-chip manner, the light emitting element including

a semiconductor stack successively having a first semiconductor layer, an emission layer, and a second semiconductor layer, with the first semiconductor layer having a plurality of exposed portions exposed from the second semiconductor layer on an upper face side of the second semiconductor layer,

an insulation film covering the semiconductor stack and having a plurality of openings respectively above the exposed portions of the first semiconductor layer,

a first electrode connected to the exposed portions of the first semiconductor layer at the openings of the insulation film and partially disposed over the second semiconductor layer via the insulation film, and

a second electrode connected to the second semiconductor layer;

a plurality of bumps disposed between the substrate and the light emitting element to mount the light emitting element on the substrate, the bumps including a plurality of first bumps bonded to the first electrode, and a plurality of second bumps bonded to the second electrode, the first bumps being spaced apart from the exposed portions of the first semiconductor layer, and the first bumps including a plurality of large bumps and a plurality of small bumps each having a smaller surface area than each of the large bumps in a plan view; and

a cover member covering the light emitting element, the bumps, and the substrate.

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

the first electrode is arranged on both sides of the second electrode in a plan view.

3. The light emitting device according to claim 1, wherein

the light emitting element has a rectangular shape in the plan view, and

the small bumps of the first bumps are arranged along two opposing sides of the rectangular shape.

4. The light emitting device according to claim 1, wherein

the first electrode continuously covers the exposed portions.

5. The light emitting device according to claim 1, wherein

a distance between adjacent ones of the second bumps is smaller than a distance between adjacent ones of the first bumps.

6. The light emitting device according to claim 1, wherein

the second electrode is connected to the second semiconductor layer via a reflective electrode.

7. The light emitting device according to claim 1, wherein

a total surface area of the first bumps connected to the first electrode is at least 25% of a surface area of the first electrode.

8. The light emitting device according to claim 1, wherein

a total surface area of the second bumps connected to the second electrode is at least 50% of a surface area of the second electrode.

9. The light emitting device according to claim 1, further comprising

a light transmissive member disposed on the light emitting element.

10. The light emitting device according to claim 9, wherein

a lower face of the light transmissive member has an area of about 80 to 150% of an upper face area of the light emitting element.

11. The light emitting device according to claim 9, wherein

the light transmissive member contains a phosphor.

12. A method for manufacturing a light emitting device comprising:

providing a substrate having a wiring pattern on an upper face thereof;

forming a plurality of bumps for bonding a light emitting element to the wiring pattern so that the bumps include a plurality of first bumps and a plurality of second bumps with the first bumps including a plurality of large bumps and a plurality of small bumps each having a smaller surface area than each of the large bumps in a plan view;

mounting the light emitting element onto the bumps in a flip-chip manner so that the first bumps are bonded to a first electrode of the light emitting element and the second bumps are bonded to a second electrode of the light emitting element; and

forming a cover member that covers lateral faces of the light emitting element and the bumps.

13. The method for manufacturing a light emitting element according to claim 12, wherein

the forming of the bumps includes forming the first bumps and the second bumps as stud bumps on the wiring pattern.

14. The method for manufacturing a light emitting element according to claim 12, wherein

the forming of the bumps includes forming the large bumps and the small bumps of the first bumps so that a height of the large bumps from the wiring pattern is different from a height of the small bumps from the wiring pattern.

15. The method for manufacturing a light emitting element according to claim 12, further comprising

disposing a light transmissive member on the light emitting element.