Light emitting device and manufacturing method thereof

• US 20040061120A1
• Filed: 09/26/2003
• Published: 04/01/2004
• Est. Priority Date: 09/30/2002
• Status: Active Grant

• Current Assignee: Fujifilm Corporation (Fujifilm Holdings Corporation)
• Original Assignee: Fuji Photo Film Co Limited (Fujifilm Holdings Corporation)
• Inventors: Mizuyoshi, Akira
• Granted Patent: US 6,995,400 B2
• Time in Patent Office: Days
• US Class Current: 257/79
• CPC Class Codes: H01L 2224/05001 Internal layers
• CPC Class Codes: H01L 2224/05023 the whole internal layer protruding from the surface
• CPC Class Codes: H01L 2224/0508 being stacked
• CPC Class Codes: H01L 2224/05099 Material
• CPC Class Codes: H01L 2224/05568 the whole external layer protruding from the surface
• CPC Class Codes: H01L 2224/05573 Single external layer
• CPC Class Codes: H01L 2224/05599 Material
• CPC Class Codes: H01L 2224/0603 Bonding areas having different sizes, e.g. different heights or widths
• CPC Class Codes: H01L 2224/06102 the bonding areas being at different heights
• CPC Class Codes: H01L 2224/16 of an individual bump connector
• CPC Class Codes: H01L 2224/1703 Bump connectors having different sizes, e.g. different diameters, heights or widths
• 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 33/20 with a particular shape, e.g. curved or truncated substrate
• CPC Class Codes: H01L 33/52 Encapsulations
• CPC Class Codes: H01L 33/58 Optical field-shaping 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

In a light emitting device, a light emitting element which includes a transparent substrate and a stack of GaN-based compound semiconductor layers formed on the first surface of the transparent substrate is mounted on a lead frame or a printed circuit board so that the transparent substrate is located on the side of the stack of GaN-based compound semiconductor layers opposite to the lead frame or the printed circuit board. The second surface of the transparent substrate opposite to the first surface contains a portion inclined with respect to the first surface. Alternatively, an optical member is arranged in contact with the second surface of the transparent substrate, where a surface of the optical member located on the opposite side to the transparent substrate contains a portion inclined with respect to the first surface of the transparent substrate.

Claims

1. A light emitting device comprising:

a light emitting element which includes a transparent substrate and a stack of GaN-based compound semiconductor layers formed on a first surface of the transparent substrate; and

one of a lead frame and a printed circuit board on which said light emitting element is mounted so that said transparent substrate is located on a side of said stack of GaN-based compound semiconductor layers opposite to the one of the lead frame and the printed circuit board;

wherein a second surface of the transparent substrate opposite to said first surface contains a portion inclined with respect to the first surface.

2. A light emitting device according to claim 1, wherein said portion of the second surface of the transparent substrate includes one or more conical surfaces, one or more pyramidal surfaces, one or more hemispherical surfaces, one or more paraboloidal surfaces, or any combination thereof.

3. A light emitting device comprising:

a light emitting element which includes a transparent substrate and a stack of GaN-based compound semiconductor layers formed on a first surface of the transparent substrate;

an optical member which is arranged in contact with a second surface of the transparent substrate opposite to said first surface, and has a surface being located on an opposite side to the transparent substrate and containing a portion inclined with respect to said first surface of the transparent substrate; and

one of a lead frame and a printed circuit board on which said light emitting element is mounted so that the transparent substrate is located on a side of the stack of GaN-based compound semiconductor layers opposite to the one of the lead frame and the printed circuit board.

4. A light emitting device according to claim 3, wherein said optical member has a function of a sealing package which seals said light emitting element.

5. A light emitting device according to claim 3, wherein said portion of the surface of the optical member includes one or more conical surfaces, one or more pyramidal surfaces, one or more hemispherical surfaces, one or more paraboloidal surfaces, or any combination thereof.

6. A light emitting device according to claim 4, wherein said portion of the surface of the optical member includes one or more conical surfaces, one or more pyramidal surfaces, one or more hemispherical surfaces, one or more paraboloidal surfaces, or any combination thereof.

7. A process for producing a light emitting device, comprising the steps of:

(a) applying a resist to a first surface of a transparent substrate located opposite to a stack of GaN-based compound semiconductor layers, where the stack of GaN-based compound semiconductor layers is formed on a second surface of the transparent substrate opposite to the first surface, and the stack of GaN-based compound semiconductor layers and the transparent substrate constitute a light emitting element;

(b) shaping said first surface of the transparent substrate by grayscale exposure and dry etching so that the first surface of the transparent substrate contains a portion inclined with respect to said second surface of the transparent substrate; and

(c) mounting said light emitting element on one of a lead frame and a printed circuit board so that the transparent substrate is located on a side of said stack of GaN-based compound semiconductor layers opposite to the one of the lead frame and the printed circuit board.