Light emitting device and light emitting device package

• US 9,991,430 B2
• Filed: 02/25/2016
• Issued: 06/05/2018
• Est. Priority Date: 09/01/2011
• Status: Active Grant

• Current Assignee: ROHM Co., Ltd.
• Original Assignee: ROHM Co., Ltd.
• Inventors: Matsui, Nobuaki, Obuchi, Hirotaka, Nakanishi, Yasuo, Tsutsumi, Kazuaki, Fujimori, Takao
• Primary Examiner(s): Maldonado, Julio J
• Assistant Examiner(s): Fortich, Rodolfo D
• Application Number:
  US15/054,110
• Publication Number:
  US 20160181489A1
• Time in Patent Office: 831 Days
• Field of Search: 257 98, 257 81, 257 76, 257 49, 257200
• CPC Class Codes: H01L 2224/48091 Arched
• CPC Class Codes: H01L 2224/49107 on the semiconductor or solid-state body
• CPC Class Codes: H01L 2224/73265 Layer and wire 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 2933/0058 relating to optical field-shaping elements
• CPC Class Codes: H01L 33/0075 comprising nitride compounds
• CPC Class Codes: H01L 33/22 Roughened surfaces, e.g. at the interface between epitaxial layers
• CPC Class Codes: H01L 33/32 containing nitrogen
• CPC Class Codes: H01L 33/46 Reflective coating, e.g. dielectric Bragg reflector
• CPC Class Codes: H01L 33/60 Reflective elements

Abstract

A light emitting device includes a light emitting layer, a substrate that is transparent to an emission wavelength of the light emitting layer and positioned to receive an emission wavelength from the light emitting layer, a convex pattern including a collection of a plurality of convex portions discretely arranged on a front surface of the substrate with a first pitch, an n type nitride semiconductor layer located on the front surface of the substrate to cover the convex pattern and a p type nitride semiconductor layer located on the light emitting layer. The light emitting layer is located on the n type semiconductor layer. Each of the convex portions includes a sub convex pattern comprising a plurality of fine convex portions discretely formed at the top of the convex portion with a second pitch smaller than the first pitch, and a base supporting the sub convex pattern.

Claims

1. A method of manufacturing a face-up type light emitting device, comprising:

forming a nitride semiconductor stacked structure by stacking an n type nitride semiconductor layer, a light emitting layer and a p type nitride semiconductor layer in order on a front surface of a substrate wafer, the substrate wafer having the front surface as a light extraction surface and a rear surface opposite the front surface, and the substrate wafer being transparent to an emission wavelength of the light emitting layer;

forming a transparent adhesive layer on the entire rear surface of the substrate wafer;

depositing a reflecting metal on the entire rear surface of the transparent adhesive layer, the reflecting metal being formed of an alloy containing Ag, a Pt group metal and Cu;

forming a bonding metal on a rear surface of the reflecting metal such that a portion of the reflecting metal is selectively exposed along a planned cutting line of the substrate wafer;

selectively exposing a portion of the transparent adhesive layer along the planned cutting line by removing the exposed portion of the reflecting metal by etching;

forming a division guide groove along the planned cutting line on the exposed transparent adhesive layer and the substrate wafer by an irradiation process from the rear surface of the substrate wafer; and

dividing the substrate wafer along the division guide groove.

2. The method of claim 1, wherein forming a bonding metal includes:

forming a resist pattern to cover a region having a predetermined width on the planned cutting line;

depositing a material of the bonding metal through the resist pattern; and

lifting off an unnecessary portion of the material of the bonding metal along with the resist pattern.

3. The method of claim 1, wherein selectively exposing a portion of the transparent adhesive layer includes:

removing the exposed portion of the reflecting metal by dry etching.

4. The method of claim 1, wherein forming a nitride semiconductor stacked structure includes:

forming the nitride semiconductor stacked structure on the substrate wafer having a thickness of 600 μ

m to 1000 μ

m; and

prior to forming a transparent adhesive layer, grinding the substrate wafer from the rear surface of the substrate wafer until the thickness of the substrate wafer reaches 200 μ

m to 300 μ

m.

5. The method of claim 1, wherein forming a transparent adhesive layer includes:

depositing a material of the transparent adhesive layer on the entire rear surface of the substrate wafer by a sputtering process.

6. The method of claim 1, wherein when the portion of the transparent adhesive layer is selectively exposed along the planned cutting line, an exposure width of the exposed portion of the transparent adhesive layer is equal to or more than 30 μ

m.

7. The method of claim 1, wherein forming a division guide groove includes:

scanning the substrate wafer with a laser light from the rear surface of the substrate wafer to form the division guide groove.

8. The method of claim 1, wherein the reflecting metal is formed of an AgPdCu alloy in which Pd is the Pt group metal.

9. The method of claim 8, wherein a mixing ratio of Pd and Cu in the reflecting metal are 0.6% and 0.2%, respectively.

10. The method of claim 1, wherein the reflecting metal is formed of an AgPtCu alloy in which Pt is the Pt group metal.

11. The method of claim 1, wherein the transparent adhesive layer is formed of ITO or ZnO.

12. The method of claim 1, wherein the bonding metal is formed of Ag, solder or an AuSn alloy.

13. The method of claim 1, wherein the substrate wafer is formed of sapphire, GaN or SiC.

14. The method of claim 1, wherein the emission wavelength is 450 nm.