Light emitting apparatus and method for mounting light emitting device

• US 6,369,506 B1
• Filed: 11/29/1999
• Issued: 04/09/2002
• Est. Priority Date: 11/27/1998
• Status: Expired due to Fees

• Current Assignee: Sharp Kabushiki Kaisha (Hon Hai Precision Industry Co., Ltd.)
• Original Assignee: Sharp Kabushiki Kaisha (Hon Hai Precision Industry Co., Ltd.)
• Inventors: Hata, Toshio
• Primary Examiner(s): Patel, Vip
• Assistant Examiner(s): BERCK, KENNETH A
• Application Number:
  US09/448,899
• Time in Patent Office: 862 Days
• Field of Search: 313/499, 313/500, 313/506, 313/512, 257/13, 257/103, 257/749, 257/81, 257/85, 257/86, 257/94, 257/99
• US Class Current: 313/499
• CPC Class Codes: H01L 2224/16 of an individual bump connector
• CPC Class Codes: H01L 2224/16245 the item being metallic
• 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 2224/48465 the other connecting portion not on the bonding area being a wedge bond, i.e. ball-to-wedge, regular stitch
• CPC Class Codes: H01L 2224/49107 on the semiconductor or solid-state body
• 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 2924/00014 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 2924/01039 Yttrium [Y]
• CPC Class Codes: H01L 2924/12041 LED
• 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
• CPC Class Codes: H01S 5/0231 Stems
• CPC Class Codes: H01S 5/0232 Lead-frames

Abstract

According to one aspect of the present invention, there is provided a light emitting apparatus including: a light emitting device for emitting light; and a first lead frame and a second lead frame on which the light emitting device is mounted. In this apparatus, the light emitting device includes: a substrate which is light transmissive, the substrate defining an output surface; a semiconductor layer formed on the substrate which includes a light emitting layer made of a nitride semiconductor; a first electrode provided lower than a plane running parallel through the light emitting layer with respect to the substrate; and a second electrode provided higher than the plane running parallel through the light emitting layer with respect to the substrate; the first lead frame includes a first lead pad section to which the first electrode is connected; the second lead frame includes a second lead pad section to which the second electrode is connected; at least one of the first and second lead frames includes a die pad section on which the substrate is mounted; and the die pad section does not substantially cover the first output surface.

Claims

1. A light emitting apparatus, comprising:

a light emitting device for emitting light; and

a first lead frame and a second lead frame on which the light emitting device is mounted, wherein;

the light emitting device includes;

a substrate which is light transmissive, the substrate defining a light output surface;

a semiconductor layer formed on the substrate, the semiconductor layer including a light emitting layer comprising a nitride semiconductor;

a first electrode provided lower than a plane running parallel through the light emitting layer with respect to the substrate; and

a second electrode provided higher than the plane running parallel through the light emitting layer with respect to the substrate;

wherein the first lead frame includes a first lead pad section to which the first electrode is connected;

wherein the second lead frame includes a second lead pad section to which the second electrode is connected;

wherein at least one of the first and second lead frames includes a die pad section on which the substrate is mounted; and

wherein the die pad section is in contact with a back-side plane or light output surface of the substrate of the light emitting device, and the die pad section is provided with a light transmission section.

2. A light emitting apparatus according to claim 1, wherein the light emitting device includes a reflective layer which reflects the light generated in the light emitting layer toward the substrate.

3. A light emitting apparatus according to claim 2, wherein the reflective layer is formed between the light emitting layer and the second electrode.

4. A light emitting apparatus according to claim 2, wherein the reflective layer is formed to surround the light emitting device.

5. A light emitting apparatus according to claim 3, wherein:

the semiconductor layer includes at least a pair of cladding layers, the light emitting layer being made of a gallium nitride type compound semiconductor and being formed between the cladding layers;

the reflective layer is a multilayer film including at least two different types of layers which are alternately deposited on one another; and

the at least two different types of layers include a first layer made of a nitride semiconductor and having a refractive index of n₁ and a thickness of λ

/(4·

n₁) (where λ

denotes an emission wavelength of the light emitting device), and a second layer made of a nitride semiconductor with a refractive index of n₂ and having a thickness of λ

/4·

n₂.

6. A light emitting apparatus according to claim 4, wherein:

the semiconductor layer includes at least a pair of cladding layers, the light emitting layer being made of a gallium nitride type compound semiconductor and being formed between the cladding layers;

the second electrode has a property of transmitting light with a specific wavelength; and

the reflective layer is an insulative multilayer film which is formed on the second electrode and reflects the light with the specific wavelength.

7. A light emitting apparatus according to claim 4, wherein:

the semiconductor layer Includes at least a pair of cladding layers, the light emitting layer being made of a gallium nitride type compound semiconductor and being formed between the cladding layers;

the second electrode has a property of transmitting light with a specific wavelength; and

the reflective layer includes;

a first insulative layer formed on the second electrode, the first insulative layer reflecting light with a specific wavelength; and

a second layer formed on the first layer, the second layer reflecting the light with the specific wavelength at a high reflectivity.

10. The light emitting apparatus of claim 1, wherein the transmissive substrate defines a light emitting plane at said light output surface that is in contact with the light transmission section of the die pad section, and is between the light transmission section and the light emitting layer.

11. The light emitting apparatus of claim 1, wherein the light transmission section of the die pad section comprises an aperture defined in the die pad section.

8. A method for mounting a light emitting device, the method comprising:

forming a semiconductor layer on a light transmissive substrate, the semiconductor layer including a light emitting layer;

forming a first electrode lower than a plane running parallel through the light emitting layer with respect to the substrate and a second electrode higher than the plane running parallel through the light emitting layer with respect to the substrate;

placing first and second lead frames in predetermined positions with respect to a light emitting device, the first lead frame including a first lead pad section to which the first electrode is connected, the second lead frame including a second lead pad section to which the second electrode is connected, and at least one of the first and second lead frames including a die pad section which is in contact with a back-side plane of the light transmissive substrate of the light emitting device, and wherein the die pad section is provided with a light transmission section.

9. A light emitting apparatus, comprising:

a light emitting device for emitting light; and

a first lead frame and a second lead frame on which the light emitting device is mounted, wherein;

the light emitting device includes;

a substrate which is light transmissive, the substrate defining a light output surface so that the light emitting device outputs light through the light output surface of the substrate;

a semiconductor layer formed on the substrate, the semiconductor layer including a light emitting layer comprising a nitride semiconductor;

a first electrode provided lower than a plane running parallel through the light emitting layer with respect to the substrate; and

a second electrode provided higher than the plane running parallel through the light emitting layer with respect to the substrate;

wherein the first lead frame includes a first lead pad section to which the first electrode is connected;

wherein the second lead frame includes a second lead pad section to which the second electrode is connected;

wherein at least one of the first and second lead frames includes a die pad section on which the light output surface of the substrate is mounted; and

wherein the die pad section does not substantially cover the light output surface of the substrate so that the light emitting device emits light through said light output surface of said substrate.