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

• US 20080303042A1
• Filed: 12/20/2007
• Published: 12/11/2008
• Est. Priority Date: 12/21/2006
• Status: Active Grant

• Current Assignee: Nichia Corporation
• Original Assignee: Nichia Corporation
• Inventors: Yamada, Motokazu, Narita, Junya, Narukawa, Yukio, Minato, Shunsuke, Wakai, Yohei
• Granted Patent: US 7,781,790 B2
• Time in Patent Office: Days
• US Class Current: 257/98
• 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 semiconductor light emitting element comprising a semiconductor light emitting structure on a first main surface of a substrate, wherein

the first main surface of the substrate has a substrate protrusion portion thereon, wherein a bottom surface of a protrusion is wider than a top surface thereof in a cross section of the substrate, or the top surface is included in the bottom surface in a top view of the substrate,

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

2. The semiconductor light emitting element according to claim 1, wherein a plurality of protrusions are spaced apart each other and arranged periodically on the first main surface.

3. The semiconductor light emitting element according to claim 2, wherein the periodic arrangement of the protrusions is triangular, quadrangular, or hexagonal lattice.

4. The semiconductor light emitting element according to claim 1, wherein each side surface of the protrusion is a complex-surface having a larger number of surfaces than the number of constituent sides of the approximately polygonal bottom surface.

5. The semiconductor light emitting element according to claim 1, wherein the shape of the bottom surface is approximately triangular.

6. The semiconductor light emitting element according to claim 1 further comprises an aligning structure having the protrusions arranged in two directions, and a direction of the constituent sides of the bottom surface of the protrusions intersects with the directions of the aligning.

7. The light emitting element according to claim 6, wherein the aligning structure includes an interval between adjacent alignments smaller than a width of the alignment.

8. A semiconductor light emitting element comprising a semiconductor light emitting structure on a first main surface of a substrate, wherein

the first main surface of the substrate has a substrate protrusion portion on the first main surface of the substrate, a bottom surface of a protrusion is wider than a top surface thereof in a cross section of the substrate, or the top surface is included in the bottom surface in a top view of the substrate, the shape of the bottom surface is approximately a curve of constant width or Reuleaux polygon.

9. The semiconductor light emitting element according to claim 8, wherein the protrusion has an upper surface having a shape of approximately a curve of constant width or Reuleaux polygon, which is a different shape than the shape of the bottom surface.

10. A method of manufacturing 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 top surface and bottom surface in different shapes and being spaced apart each other, and

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

11. The method of manufacturing a semiconductor light emitting element according to claim 10, wherein in the process of forming the protrusion/recess structure further comprises steps of forming the bottom surface of the protrusion wider than the top surface thereof in a cross section of the substrate, or forming the bottom surface of the protrusion 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.

12. The method of manufacturing a semiconductor light emitting element according to claim 10, 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.

13. The method of manufacturing a semiconductor light emitting element according to claim 10, 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.

14. The method of manufacturing 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.

15. The method of manufacturing a semiconductor light emitting element according to claim 10, 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.

17. The method of manufacturing a semiconductor light emitting element according to claim 11, 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.

18. The method of manufacturing a semiconductor light emitting element according to claim 17, 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 17.

19. 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.