Method for manufacturing substrate for semiconductor light emitting element and semiconductor light emitting element using the same

• US 8,394,652 B2
• Filed: 06/15/2010
• Issued: 03/12/2013
• Est. Priority Date: 12/21/2006
• Status: Active Grant

• Current Assignee: Nichia Corporation
• Original Assignee: Nichia Corporation
• Inventors: Minato, Shunsuke, Narita, Junya, Wakai, Yohei, Narukawa, Yukio, Yamada, Motokazu
• Primary Examiner(s): Louie, Wai Sing
• Application Number:
  US12/816,186
• Publication Number:
  US 20100255621A1
• Time in Patent Office: 1,001 Days
• Field of Search: 438/22, 438/24, 438/27, 438/29, 438/47
• US Class Current: 438/22
• CPC Class Codes: H01L 2224/48095 Kinked
• CPC Class Codes: H01L 2224/48247 connecting the wire to a bond pad of the item
• CPC Class Codes: H01L 2224/48465 the other connecting portion not on the bonding area being a wedge bond, i.e. ball-to-wedge, regular stitch
• 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 2924/01012 Magnesium [Mg]
• CPC Class Codes: H01L 2924/01019 Potassium [K]
• CPC Class Codes: H01L 2924/0102 Calcium [Ca]
• CPC Class Codes: H01L 2924/01046 Palladium [Pd]
• CPC Class Codes: H01L 2924/01057 Lanthanum [La]
• CPC Class Codes: H01L 2924/01063 Europium [Eu]
• CPC Class Codes: H01L 2924/01077 Iridium [Ir]
• CPC Class Codes: H01L 2924/01078 Platinum [Pt]
• CPC Class Codes: H01L 2924/01079 Gold [Au]
• CPC Class Codes: H01L 2924/01322 Eutectic Alloys, i.e. obtained by a liquid transforming into two solid phases
• CPC Class Codes: H01L 33/10 with a light reflecting structure, e.g. semiconductor Bragg reflector
• CPC Class Codes: H01L 33/20 with a particular shape, e.g. curved or truncated substrate
• CPC Class Codes: H01L 33/24 of the light emitting region, e.g. non-planar junction
• CPC Class Codes: H01L 33/32 containing nitrogen

Abstract

A light emitting element having a recess-protrusion structure on a substrate is provided. A semiconductor light emitting element 100 has a light emitting structure of a semiconductor 20 on a first main surface of a substrate 10. The first main surface of the substrate 10 has substrate protrusion portion 11, the bottom surface 14 of each protrusion is wider than the top surface 13 thereof in a cross-section, or the top surface 13 is included in the bottom surface 14 in a top view of the substrate. The bottom surface 14 has an approximately polygonal shape, and the top surface 13 has an approximately circular or polygonal shape with more sides than that of the bottom surface 14.

Claims

1. A method of manufacturing a substrate of a semiconductor light emitting element comprising processes of:

providing a mask on a first main surface of a substrate,

forming a protrusion/recess structure on the first main surface of the substrate by carrying out an etching through the mask so as to form a plurality of protrusions each having a top surface and a bottom surface in different shapes and being spaced apart from each other, and

forming a semiconductor substrate by growing semiconductor on a surface of the recess/protrusion structure,

wherein the process of providing a mask comprises steps of forming a first mask which defines the shape of the bottom surface of protrusions, and forming a second mask which defines the shape of the top surface of the protrusions on the first mask.

2. The method of manufacturing a substrate of a semiconductor light emitting element according to claim 1, wherein the process of forming the protrusion/recess structure further comprises steps of:

forming the bottom surface of each of the protrusions wider than the top surface thereof in a cross section of the substrate, or forming the bottom surface of each of the protrusions so as to include the top surface in a top view of the substrate, and

forming the bottom surface in an approximately polygonal shape, and forming the top surface in approximately circular shape or approximately polygonal shape with a larger number of constituent sides than the number of the constituent sides of the bottom surface.

5. The method of manufacturing a substrate of a semiconductor light emitting element according to claim 1, wherein the process of forming a recess/protrusion structure includes a step of periodically arranging the protrusions in the first main surface of the substrate in a triangular, quadrangular, or hexagonal lattice.

6. The method of manufacturing a substrate of a semiconductor light emitting element according to claim 2, wherein the process of forming a recess/protrusion structure includes steps of aligning the protrusions in two directions and forming a direction of the constituent sides of the bottom surface of the protrusions intersects with the directions of the aligning directions.

7. The method of manufacturing a substrate of a semiconductor light emitting element according to claim 6, wherein the process of forming a recess/protrusion structure includes steps of forming an interval between adjacent alignments smaller than a width of the alignment, and aligning the protrusions in the directions as in claim 6.

9. The method of manufacturing a substrate of a semiconductor light emitting element according to claim 1, wherein the first mask and the second mask have different shapes.

10. The method of manufacturing a substrate of a semiconductor light emitting element according to claim 1, wherein in the process of forming a protrusion/recess structure, the etching is carried out until the second mask is removed, to form the protrusions.

11. The method of manufacturing a substrate of a semiconductor light emitting element according to claim 9, wherein the substrate is a sapphire substrate, and wherein in the process of forming the protrusion/recess structure, wet etching is carried out using an etching solution of phosphoric acid or pyrophosphoric acid, a mixed acid of phosphoric or pyrophosphoric acid with additional sulfuric acid, or solution of potassium hydroxide.

12. The method of manufacturing a substrate of a semiconductor light emitting element according to claim 11, wherein the mask is made of SiO₂.

3. A method of manufacturing a substrate of a semiconductor light emitting element comprising processes of:

providing a mask on a first main surface of a substrate;

forming a protrusion/recess structure on the first main surface of the substrate by carrying out an etching through the mask so as to form a plurality of protrusions each having a top surface and a bottom surface in different shapes and being spaced apart from each other; and

forming a semiconductor substrate by growing semiconductor on a surface of the recess/protrusion structure,

wherein the process of forming a recess/protrusion structure is carried out by wet etching and the process includes a step of forming the shape of the bottom surface of the protrusions to include a crystal shape of substrate defined by the wet etching.

13. The method of manufacturing a substrate of a semiconductor light emitting element according to claim 3, wherein in the process of forming the protrusion/recess structure, the top surface of each of the protrusions is formed with an acuminate shape.

14. The method of manufacturing a substrate of a semiconductor light emitting element according to claim 3, wherein in the process of forming the protrusion/recess structure, each of the protrusions is formed in a pyramid shape.

15. The method of manufacturing a substrate of a semiconductor light emitting element according to claim 3, wherein the process of providing a mask includes forming the mask in an approximately circular shape, and the process of forming a recess/protrusion structure includes forming the bottom surface in a shape approximately a curve of constant width or Reuleaux polygon.

16. The method of manufacturing a substrate of a semiconductor light emitting element according to claim 13, wherein the process of providing a mask includes forming the mask in an approximately circular shape, and the process of forming a recess/protrusion structure includes forming the bottom surface in a shape approximately a curve of constant width or Reuleaux polygon.

17. The method of manufacturing a substrate of a semiconductor light emitting element according to claim 14, wherein the process of providing a mask includes forming the mask in an approximately circular shape, and the process of forming a recess/protrusion structure includes forming the bottom surface in a shape approximately a curve of constant width or Reuleaux polygon.

18. The method of manufacturing a substrate of a semiconductor light emitting element according to claim 3, wherein the first main surface of the substrate is a C-plane of a sapphire substrate.

19. The method of manufacturing a substrate of a semiconductor light emitting element according to claim 3, wherein the process of forming a recess/protrusion structure includes a step of periodically arranging the protrusions in the first main surface of the substrate in a triangular, quadrangular, or hexagonal lattice.

20. The method of manufacturing a substrate of a semiconductor light emitting element according to claim 3, wherein the process of forming the protrusion/recess structure further comprises steps of:

forming the bottom surface of each of the protrusions wider than the top surface thereof in a cross section of the substrate, or forming the bottom surface of each of the protrusions so as to include the top surface in a top view of the substrate, and

forming the bottom surface in an approximately polygonal shape, and forming the top surface in approximately circular shape or approximately polygonal shape with a larger number of constituent sides than the number of the constituent sides of the bottom surface.

21. The method of manufacturing a substrate of a semiconductor light emitting element according to claim 20, wherein the process of forming a recess/protrusion structure includes steps of aligning the protrusions in two directions and forming a direction of the constituent sides of the bottom surface of the protrusions intersects with the directions of the aligning directions.

22. The method of manufacturing a substrate of a semiconductor light emitting element according to claim 21, wherein the process of forming a recess/protrusion structure includes steps of forming an interval between adjacent alignments smaller than a width of the alignment, and aligning the protrusions in the directions as in claim 21.

4. A method of manufacturing a substrate of a semiconductor light emitting element comprising processes of:

providing a mask on a first main surface of a substrate;

forming a protrusion/recess structure on the first main surface of the substrate by carrying out an etching through the mask so as to form a plurality of protrusions each having a top surface and a bottom surface in different shapes and being spaced apart from each other; and

forming a semiconductor substrate by growing semiconductor on a surface of the recess/protrusion structure,

wherein the process of providing a mask includes forming the mask in an approximately circular shape, and the process of forming a recess/protrusion structure includes forming the bottom surface in a shape approximately a curve of constant width or Reuleaux polygon.

8. A method of manufacturing a substrate of a semiconductor light emitting element comprising processes of:

providing a mask having a shape of a curve of constant width on a first main surface of a substrate, and

forming a protrusion/recess structure having a plurality of protrusions spaced apart each other on the first main surface of the substrate by carrying out a wet etching through the mask, so as to form a plurality of protrusions each having a bottom surface with a shape different than that of the mask, which is approximately a curve of constant width or a Reuleaux polygon including a crystal shape of the substrate defined by the etching.