Self-aligned floating mirror for contact vias

• US 10,186,644 B2
• Filed: 09/21/2015
• Issued: 01/22/2019
• Est. Priority Date: 06/24/2011
• Status: Active Grant

• Current Assignee: Creeled Incorporated
• Original Assignee: CREE Incorporated (Wolfspeed, Inc.)
• Inventors: Mayer, Eric, Park, Jae, Breva, Manuel L.
• Primary Examiner(s): Galvin, III, Joseph
• Application Number:
  US14/860,483
• Publication Number:
  US 20160087173A1
• Time in Patent Office: 1,219 Days
• CPC Class Codes: H01L 2224/32245 the item being metallic
• CPC Class Codes: H01L 2224/32257 the layer connector connecting to a bonding area disposed in a recess of the surface of the item
• CPC Class Codes: H01L 2224/45015 being circular
• CPC Class Codes: H01L 2224/45099 Material
• CPC Class Codes: H01L 2224/48091 Arched
• CPC Class Codes: H01L 2224/48247 connecting the wire to a bond pad of the item
• CPC Class Codes: H01L 2224/73265 Layer and wire connectors
• CPC Class Codes: H01L 25/0753 the devices being arranged next to each other
• CPC Class Codes: H01L 27/15 including semiconductor components having potential barriers, specially adapted for light emission
• CPC Class Codes: H01L 27/156 two-dimensional arrays
• 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 2924/00012 Relevant to the scope of the group, the symbol of which is combined with the symbol of this group
• 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 2924/181 Encapsulation
• CPC Class Codes: H01L 2924/207 Diameter ranges
• CPC Class Codes: H01L 2933/0016 relating to electrodes
• CPC Class Codes: H01L 2933/0025 relating to coatings
• CPC Class Codes: H01L 2933/0058 relating to optical field-shaping elements
• CPC Class Codes: H01L 2933/0066 relating to arrangements for conducting electric current to or from the semiconductor body
• CPC Class Codes: H01L 33/08 with a plurality of light emitting regions, e.g. laterally discontinuous light emitting layer or photoluminescent region integrated within the semiconductor body H01L27/15 takes precedence
• CPC Class Codes: H01L 33/382 : the electrode extending partially in or entirely through the semiconductor body
• CPC Class Codes: H01L 33/405 : Reflective materials
• CPC Class Codes: H01L 33/46 : Reflective coating, e.g. dielectric Bragg reflector
• 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

Described herein are LED chips incorporating self-aligned floating mirror layers that can be configured with contact vias. These mirror layers can be utilized to reduce dim areas seen around the contact vias due to underlying material layers without the need for the mirror layer to be designed at some tolerance distance from the electrical via. This increases mirror area, eliminating lower light reflection in the proximity of the via and producing higher light output with greater light emission uniformity. In some embodiments, the mirror layer is formed with a contact via. This allows for a self-aligning process and results in the mirror layer extending substantially from the edge of the via.

Claims

1. A light emitting diode (LED), comprising:

a first active region comprising two oppositely doped layers and an active layer therebetween;

at least one contact via providing a path for electrical connection to one of said oppositely doped layers;

a reflective layer extending from a position substantially near an edge of said at least one contact via, said reflective layer distinct from said at least one contact via; and

an insulation layer substantially surrounding said reflective layer.

2. The LED of claim 1, wherein said reflective layer surrounds said at least one contact via.

3. The LED of claim 1, wherein said reflective layer is in contact with said at least one contact via at a first side of said reflective layer and said reflective layer is surrounded by said insulation layer on all other sides.

4. The LED of claim 1, wherein at least one additional layer is between said reflective layer and said at least one contact via.

5. The LED of claim 1, further comprising at least one additional active region physically separated from said first active region.

6. The LED of claim 5, further comprising at least one interconnect layer connecting one of said doped layers of said first active region with an oppositely doped layer of said at least one additional active region.

7. The LED of claim 6, wherein said LED chip comprises at least four active regions physically separated from one another and electrically connected by said at least one interconnect layer to produce a 12 volt LED device.

8. The LED of claim 7, wherein said at least four active regions are electrically connected in series.

9. The LED of claim 1, wherein said at least one contact via comprises a contact comprising a material that is resistant to electromigration.

10. The LED of claim 9, wherein said contact comprises a material selected from the group consisting of titanium, platinum, nickel and tungsten.

11. The LED of claim 1, further comprising at least one additional reflector layer.

16. The LED of claim 11, wherein said plurality of active regions is electrically connected in series.

12. A light emitting diode (LED), comprising:

a plurality of active regions physically separated from one another, each active region comprising two oppositely doped layers and an active layer therebetween;

at least one interconnect layer connecting one of said doped layers of one active region with an oppositely doped layer of another active region, wherein at least a portion of said at least one interconnect layer is in a contact via providing a path for electrical connection to one of said active regions in said plurality;

a reflective layer extending from a position substantially near an edge of said contact via, said reflective layer distinct from said interconnect layer; and

an insulation layer substantially surrounding said reflective layer.

13. The LED of claim 12, wherein said reflective layer surrounds said at least one contact via.

14. The LED of claim 12, wherein said reflective layer is in contact with said interconnect layer at a first side of said reflective layer and said reflective layer is surrounded by said insulation layer on all other sides.

15. The LED of claim 14, wherein said at least one interconnect layer comprises a material selected from the group consisting of titanium, platinum, nickel and tungsten.