U.S. patent application number 12/533211 was filed with the patent office on 2010-02-04 for light-emitting device containing a composite electroplated substrate.
This patent application is currently assigned to EPISTAR CORPORATION. Invention is credited to Min-Hsun HSIEH, Chia-Liang HSU, Chien-Fu HUANG, Chih-Chiang LU.
Application Number | 20100025714 12/533211 |
Document ID | / |
Family ID | 41607417 |
Filed Date | 2010-02-04 |
United States Patent
Application |
20100025714 |
Kind Code |
A1 |
HSU; Chia-Liang ; et
al. |
February 4, 2010 |
LIGHT-EMITTING DEVICE CONTAINING A COMPOSITE ELECTROPLATED
SUBSTRATE
Abstract
The application is related to a method of forming a substrate of
a light-emitting diode by composite electroplating. The application
illustrates a light-emitting diode comprising the following
elements: a light-emitting epitaxy structure, a reflective layer
disposed on the light-emitting epitaxy structure, a seed layer
disposed on the reflective layer, a composite electroplating
substrate disposed on the seed layer by composite electroplating,
and a protection layer disposed on the composite electroplating
substrate.
Inventors: |
HSU; Chia-Liang; (Changhua
County, TW) ; HSIEH; Min-Hsun; (Hsinchu, TW) ;
LU; Chih-Chiang; (Hsinchu County, TW) ; HUANG;
Chien-Fu; (Chiayi, TW) |
Correspondence
Address: |
Muncy, Geissler, Olds & Lowe, PLLC
P.O. BOX 1364
FAIRFAX
VA
22038-1364
US
|
Assignee: |
EPISTAR CORPORATION
Hsinchu
TW
|
Family ID: |
41607417 |
Appl. No.: |
12/533211 |
Filed: |
July 31, 2009 |
Current U.S.
Class: |
257/98 ; 257/103;
257/13; 257/14; 257/94; 257/E33.008; 257/E33.013; 257/E33.055 |
Current CPC
Class: |
H01L 33/0093 20200501;
H01L 33/46 20130101; H01L 33/405 20130101 |
Class at
Publication: |
257/98 ; 257/94;
257/103; 257/13; 257/14; 257/E33.008; 257/E33.013; 257/E33.055 |
International
Class: |
H01L 33/00 20060101
H01L033/00 |
Foreign Application Data
Date |
Code |
Application Number |
Aug 1, 2008 |
TW |
097129481 |
Claims
1. A light-emitting diode, comprising: a composite electroplating
substrate having a first surface and a second surface; an
interfacial layer on the first surface of the composite
electroplating substrate; a seed layer on the interfacial layer; a
reflective layer on the seed layer; and a semiconductor epitaxy
structure on the reflective layer, comprising a first conductivity
type semiconductor layer, an active layer, and a second
conductivity type semiconductor layer.
2. The light-emitting diode according to claim 1, further including
a protection layer on the second surface of the composite
electroplating substrate.
3. The light-emitting diode according to claim 1, further including
an intermediate layer between the reflective layer and the seed
layer.
4. The light-emitting diode according to claim 3, wherein the
intermediate layer is a patterned structure.
5. The light-emitting diode according to claim 1, further including
a multiple-film layer between the reflective layer and the seed
layer.
6. The light-emitting diode according to claim 1, wherein the
material of the composite electroplating substrate can be
copper-diamond, copper-silicon carbide, nickel-silicon carbide,
carbon nanotube-nickel, carbon nanotube-copper, or carbon nano
fiber-copper.
7. The light-emitting diode according to claim 1, wherein the
composite electroplating substrate is formed by the composite
electroplating method.
8. The light-emitting diode according to claim 1, wherein the
material of the interfacial layer can be copper, gold, nickel, or
tin.
9. The light-emitting diode according to claim 1, wherein the seed
layer can be a stack of titanium/gold, titanium/copper,
chromium/gold, or chromium/platinum/gold.
10. The light-emitting diode according to claim 1, wherein the
reflective layer can be a stack of titanium/aluminum,
titanium/gold, or titanium/silver.
11. The light-emitting diode according to claim 1, wherein the
first conductivity type semiconductor layer is n-type semiconductor
containing at least one or more elements selected from the group
consisting of gallium and nitrogen, and the second conductivity
type semiconductor layer is p-type semiconductor containing at
least one or more elements selected from the group consisting of
gallium and nitrogen.
12. The light-emitting diode according to claim 1, wherein the
first conductivity type semiconductor layer is n-type semiconductor
containing at least one or more elements selected from the group
consisting of aluminum, gallium, indium, and phosphorous, and the
second conductivity type semiconductor layer is p-type
semiconductor containing at least one or more elements selected
from the group consisting of aluminum, gallium, indium, and
phosphorous.
13. The light-emitting diode according to claim 2, wherein the
material of the protection layer can be gold or nickel.
14. The light-emitting diode according to claim 3, wherein the
intermediate layer is a patterned structure comprising a low
thermal expansion coefficient material.
15. The light-emitting diode according to claim 14, wherein the
material of the intermediate layer can be nickel, nickel cobalt
alloy, nickel phosphorus alloy, nickel ion alloy, copper tungsten
alloy, or copper molybdenum alloy.
16. The light-emitting diode according to claim 5, wherein the
multiple-film layer is stacked alternately by multiple high
strength films and multiple high toughness films.
17. The light-emitting diode according to claim 16, wherein the
material of the multiple-film layer can be a stack of aluminum
nitride/aluminum, aluminum nitride/copper, or titanium
tungsten/aluminum.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application claims the right of priority based on
Taiwan Patent Application No. 097129481 entitled "A Light-Emitting
Device Containing a Composite Electroplated Substrate", filed on
Aug. 1, 2008, which is incorporated herein by reference and
assigned to the assignee herein.
TECHNICAL FIELD
[0002] The present application generally relates to a
light-emitting device, and more particularly to a light-emitting
diode comprising a composite electroplated substrate.
BACKGROUND
[0003] The vertical type light-emitting diodes (LEDs) become a
popular choice to light-emitting diodes package for its simple
design, high power, high efficiency, and long life-time. To
optimize the heat dispersion, the light-emitting diodes are usually
attached to the metal substrate by bonding technology, or by
electroplating technology to evaporate metal film on the epitaxy
layers. However, due to the difference of the thermal expansion
coefficients of materials, the light-emitting diode wafer often
cracks during the manufacturing which influences the wafer
life-time indirectly.
[0004] Generally, a metal matrix composite material is produced by
fusing materials having low thermal expansion coefficient with
metals having high thermal conductivity in a high temperature
process to achieve high thermal conductivity and low thermal
expansion coefficient. However, the high temperature process does
not suit for light-emitting diode chip manufacturing. Recently, the
composite electroplating has developed vigorously. The various
kinds of composite material compositions have been developed and
used in the surface coating for the purpose of wear-resisting and
waterproof. Taking the nickel-silicon carbide composite
electroplating as an example, the principle is to precipitate and
co-coat nickel and silicon carbide on the substrate by the
electroplating solution containing the nickel ions with the inert
silicon carbide particles suspended therein. When there is stress
existed between the composite electroplating layer and the
substrate, the material(s) selection of the interfacial layer, the
number of layers, and the thickness of each layer are important
topics for considering.
SUMMARY
[0005] In one embodiment of the present application, a
light-emitting diode includes a light-emitting epitaxy structure, a
reflective layer on the light-emitting epitaxy structure, a seed
layer on the reflective layer, a composite electroplating substrate
on the seed layer, and a protection layer on the composite
electroplating substrate.
[0006] In one embodiment of the present application, a
light-emitting diode further includes an interfacial layer between
the seed layer and the composite electroplating substrate.
[0007] In one embodiment of the present application, a
light-emitting diode further includes an intermediate layer between
the reflective layer and the seed layer.
[0008] In one embodiment of the present application, a
light-emitting diode further includes a multiple-film layer stacked
alternately by multiple high strength films and multiple high
toughness films between the reflective layer and the seed
layer.
[0009] In one embodiment of the present application, a
light-emitting diode comprises an interfacial layer wherein the
material of the interfacial layer can be copper, gold, or
nickel.
[0010] In one embodiment of the present application, a
light-emitting diode comprises a reflective layer wherein the
material of the reflective layer can be as a stack of
titanium/aluminum, titanium/gold, or titanium/silver.
[0011] In one embodiment of the present application, a
light-emitting diode comprises a seed layer wherein the material of
the seed layer can be as a stack of titanium/gold, titanium/copper,
chromium/gold, or chromium/platinum/gold.
[0012] In one embodiment of the present application, a
light-emitting diode comprises a composite electroplating substrate
is formed by the composite electroplating method wherein the
material of the composite electroplating substrate can be
copper-diamond, copper-silicon carbide, nickel-silicon carbide,
carbon nanotube-nickel, carbon nanotube-copper, or carbon
nanofiber-copper.
[0013] In one embodiment of the present application, a
light-emitting diode comprises a protection layer wherein the
material of the protection layer can be gold or nickel.
[0014] In one embodiment of the present application, a
light-emitting diode comprises an intermediate layer wherein the
material of the intermediate layer can be nickel, nickel cobalt,
copper tungsten, copper molybdenum, nickel phosphorus alloy, or
nickel ion alloy.
[0015] In one embodiment of the present application, a
light-emitting diode comprises a multiple-film layer stacked
alternately by multiple high strength films and multiple high
toughness films, wherein the material of the multiple-film layer
can be as a stack of aluminum nitride/aluminum, aluminum
nitride/copper, or titanium tungsten/aluminum.
BRIEF DESCRIPTION OF THE DRAWINGS
[0016] The foregoing aspects and many of the attendant advantages
of this invention will become more readily appreciated as the same
becomes better understood by reference to the following detailed
description, when taken in conjunction with the accompanying
drawings, wherein:
[0017] FIGS. 1A-1F illustrate a process flow of forming a
light-emitting diode in accordance with one embodiment of the
present application;
[0018] FIGS. 2A-2B illustrate a process flow of forming a
light-emitting diode in accordance with another embodiment of the
present application;
[0019] FIGS. 3A-3B illustrate a process flow of forming a
light-emitting diode in accordance with further another embodiment
of the present application.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0020] The first embodiment of the present application is
illustrated in FIG. 1A to FIG. 1F. Referring to FIG. 1A, a growth
substrate 101 is provided. A semiconductor epitaxy structure 105 is
formed on the growth substrate, included at least a first
conductivity type semiconductor layer 102, an active layer 103, and
a second conductivity type semiconductor layer 104. In this
embodiment, the first conductivity type semiconductor layer 102 is
an n-GaN layer, the active layer 103 is an InGaN/GaN multiple
quantum wells structure, and the second conductivity type
semiconductor layer 104 is a p-GaN layer. The semiconductor epitaxy
structure 105 is formed on sapphire by the epitaxy technology. The
reflective layer 106 is formed on the semiconductor epitaxy
structure 105 as a stack of titanium (thickness is 30 nm)/aluminum
(thickness is 200 nm). It can also be as a stack of titanium/gold
or titanium/silver.
[0021] Referring to FIG. 1B, a seed layer 107 is formed on the
reflective layer 106 to form a stack of titanium (thickness is 30
nm)/gold (thickness is 200 nm). It can also be as a stack of
titanium/copper, chromium/gold, or chromium/platinum/gold.
Referring to FIG. 1C, an intermediate layer 108 is formed on the
seed layer 107, and can be composed of copper with a thickness of
3-5 .mu.m in this embodiment. The intermediate layer can be a
single layer or multiple layers structure. It also can be composed
of gold or nickel. The above-mentioned structure is disposed in the
copper ion electroplating solution with diamond powder suspended
therein to perform a composite electroplating process. A composite
electroplating substrate 109 is then formed by the copper and the
diamond precipitating on the intermediate layer, as shown in FIG.
1D. The composite electroplating substrate can be a single layer or
multiple layers structure. The material of the composite
electroplating substrate can also be copper-silicon carbide,
nickel-silicon carbide, carbon nanotube-nickel, carbon
nanotube-copper, or carbon nano fiber-copper.
[0022] The protection layer 110 is formed on the composite
electroplating substrate because the diamond particles can
influence the coating layer surface coarseness and oxidize copper
greatly. The protection layer can be a single layer or multiple
layers structure. The material of the protection layer can be gold
or nickel, as shown in FIG. 1E. Finally, the growth substrate 101
is removed, and the light-emitting diode structure with composite
electroplated substrate is formed as shown in FIG. 1F.
[0023] An intermediate layer 111 or a high strength and high
toughness multiple-film layer 112 is formed on the reflective layer
106 if the difference of the thermal expansion coefficient between
the semiconductor epitaxy structure 105 and the composite
electroplating substrate 109 is large, then the composite
electroplating process is proceeded. Referring to FIG. 2A, the
intermediate layer 111 is a patterned structure and composed of the
material(s) with low thermal expansion coefficient, they can be
nickel, nickel cobalt alloy, nickel phosphorous alloy, nickel ion
alloy, copper tungsten alloy, or copper molybdenum alloy. The
intermediate layer can be a single layer or multiple layers
structure. The following steps are the same as FIG. 1B to FIG. 1F
to form the light-emitting diode structure 200 as shown in FIG. 2B.
Referring to FIG. 3A, the purpose of forming the high strength and
high toughness multiple-film layer 112 on the reflective layer 106
is to release the stress and to protect the semiconductor epitaxy
structure when the difference of the thermal expansion coefficient
between the semiconductor epitaxy structure 105 and the composite
electroplating substrate 109 is large. The high strength and high
toughness multiple-film layer is stacked alternately by the
multiple hard films and the multiple soft films, and the material
of the multiple-film layer be as a stack of aluminum
nitride/aluminum, aluminum nitride/copper, or titanium
tungsten/aluminum. The number of stacked layers and the thickness
of each layer can be adjusted for product performance concerns. The
following steps are the same as FIG. 1B to FIG. 1F to form the
light-emitting diode structure 300 as shown in FIG. 3B.
[0024] Other embodiments of the application will be apparent to
those skilled in the art from consideration of the specification
and practice of the invention disclosed herein. It is intended that
the specification and examples be considered as exemplary only,
with a true scope and spirit of the invention being indicated by
the following claims.
* * * * *