CN113594332A

CN113594332A - Flip LED and manufacturing method thereof

Info

Publication number: CN113594332A
Application number: CN202110891368.1A
Authority: CN
Inventors: 陈德伪; 翁启伟; 刘英策; 刘宇轩
Original assignee: Jiangxi Qianzhao Photoelectric Co ltd
Current assignee: Jiangxi Qianzhao Photoelectric Co ltd
Priority date: 2021-08-04
Filing date: 2021-08-04
Publication date: 2021-11-02

Abstract

The invention provides a flip LED and a manufacturing method thereof, wherein the flip LED comprises the following steps: a substrate; an epitaxial layer structure disposed on one side of the substrate; the first electrode layer is arranged on one side, away from the substrate, of the epitaxial layer structure; the first DBR layer is arranged on one side, away from the substrate, of the first electrode layer, a plurality of first through holes are formed in the first DBR layer, and the first through holes are used for exposing the first electrode layer; the second electrode layer is arranged on one side, away from the substrate, of the first DBR layer, the second electrode layer is in contact with the first electrode layer through the first through holes, a plurality of second through holes are formed in the second electrode layer, and the second through holes are used for exposing the first DBR layer; and the second DBR layer is arranged on the side, away from the substrate, of the second electrode layer, and the second DBR layer is in contact with the first DBR layer through the second through hole. This flip-chip LED has filled the reflectivity of first through-hole in the first DBR layer through the structure of two-layer DBR layer to this luminance that improves flip-chip LED.

Description

Flip LED and manufacturing method thereof

Technical Field

The invention relates to the technical field of LEDs, in particular to a flip LED and a manufacturing method thereof.

Background

With the continuous development of scientific technology, LEDs (Light Emitting diodes) are used as novel Light Emitting devices, and compared with traditional Light Emitting devices, LEDs have the advantages of energy saving, environmental protection, good color rendering and response speed, and the like, and are widely applied to life and work of people, thereby bringing great convenience to daily life of people.

Based on the flip-chip LED, the LED has the advantages of high brightness, high light extraction efficiency, low thermal resistance in packaging, no risk of gold wire breakage, and side wall passivation layer protection, and is widely used in the fields of illumination, flash lamps, backlight, and the like.

However, the current flip-chip LED still has the problem of brightness loss; therefore, how to provide a high-brightness flip-chip LED is a technical problem that needs to be solved by those skilled in the art.

Disclosure of Invention

In view of the above, in order to solve the above problems, the present invention provides a flip-chip LED and a method for manufacturing the same, and the technical scheme is as follows:

a flip-chip LED, comprising:

a substrate;

an epitaxial layer structure disposed on one side of the substrate;

the first electrode layer is arranged on one side, away from the substrate, of the epitaxial layer structure;

the first DBR layer is arranged on one side, away from the substrate, of the first electrode layer, a plurality of first through holes are formed in the first DBR layer, and the first through holes are used for exposing the first electrode layer;

the second electrode layer is arranged on one side, away from the substrate, of the first DBR layer, the second electrode layer is in contact with the first electrode layer through the first through holes, a plurality of second through holes are formed in the second electrode layer, and the second through holes are used for exposing the first DBR layer;

and the second DBR layer is arranged on the side, away from the substrate, of the second electrode layer, and the second DBR layer is in contact with the first DBR layer through the second through hole.

Preferably, in the above flip-chip LED, an orthographic projection of the first through hole does not overlap with an orthographic projection of the second through hole in a direction perpendicular to a plane of the substrate.

Preferably, in the flip-chip LED, the first DBR layer and the second DBR layer are made of the same material.

Preferably, in the above flip-chip LED, the thickness of the first DBR layer is 2um to 5 um;

the thickness of the second DBR layer is 2um-5 um.

Preferably, in the above flip LED, the flip LED further includes:

a PAD layer disposed on a side of the second DBR layer facing away from the substrate; the PAD layer is in contact with the second electrode layer.

Preferably, in the above flip-chip LED, the epitaxial-layer structure includes:

the N-type semiconductor layer, the multi-quantum well layer and the P-type semiconductor layer are sequentially arranged on the substrate;

the epitaxial layer structure further includes:

a groove penetrating through the P-type semiconductor layer and the multi-quantum well layer, wherein the groove is used for exposing the N-type semiconductor layer;

wherein the first electrode layer is partially arranged on the N-type semiconductor layer and partially arranged on the P-type semiconductor layer.

Preferably, in the above flip LED, the flip LED further includes:

a current blocking layer and a current diffusion layer sequentially arranged between the P-type semiconductor layer and the first electrode layer;

wherein the current blocking layer is disposed adjacent to the P-type semiconductor layer.

Preferably, in the above flip-chip LED, the current blocking layer has a thickness of 2000 to 5000 angstroms.

Preferably, in the above flip-chip LED, the current diffusion layer has a thickness of 200 to 2000 angstroms.

A method of fabricating a flip-chip LED, the method comprising:

providing a substrate;

forming an epitaxial layer structure on one side of the substrate;

forming a first electrode layer on one side of the epitaxial layer structure, which is far away from the substrate;

forming a first DBR layer on one side, away from the substrate, of the first electrode layer, wherein a plurality of first through holes are formed in the first DBR layer and are used for exposing the first electrode layer;

forming a second electrode layer on one side of the first DBR layer, which is far away from the substrate, wherein the second electrode layer is in contact with the first electrode layer through the first through holes, and a plurality of second through holes are formed in the second electrode layer and used for exposing the first DBR layer;

and forming a second DBR layer on the side of the second electrode layer, which faces away from the substrate, wherein the second DBR layer is in contact with the first DBR layer through the second through hole.

Compared with the prior art, the invention has the following beneficial effects:

the invention provides a flip-chip LED comprising: a substrate; an epitaxial layer structure disposed on one side of the substrate; the first electrode layer is arranged on one side, away from the substrate, of the epitaxial layer structure; the first DBR layer is arranged on one side, away from the substrate, of the first electrode layer, a plurality of first through holes are formed in the first DBR layer, and the first through holes are used for exposing the first electrode layer; the second electrode layer is arranged on one side, away from the substrate, of the first DBR layer, the second electrode layer is in contact with the first electrode layer through the first through holes, a plurality of second through holes are formed in the second electrode layer, and the second through holes are used for exposing the first DBR layer; and the second DBR layer is arranged on the side, away from the substrate, of the second electrode layer, and the second DBR layer is in contact with the first DBR layer through the second through hole. This flip-chip LED has filled the reflectivity of first through-hole in the first DBR layer through the structure of two-layer DBR layer to this luminance that improves flip-chip LED.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the provided drawings without creative efforts.

Fig. 1 is a schematic structural diagram of a flip-chip LED according to an embodiment of the present invention;

fig. 2 is a schematic flow chart of a method for manufacturing a flip-chip LED according to an embodiment of the present invention;

FIGS. 3-12 are schematic structural diagrams corresponding to the manufacturing method shown in FIG. 2;

fig. 13 is a schematic flow chart illustrating another method for manufacturing a flip-chip LED according to an embodiment of the present invention;

fig. 14 is a schematic structural diagram corresponding to the manufacturing method shown in fig. 13.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

Based on the description of the background art, after the DBR layer in the flip-chip LED in the prior art is etched and opened, the reflectivity in the DBR hole is reduced, and a part of light cannot be reflected to the back surface of the flip-chip LED, so that the brightness of the flip-chip LED is somewhat lost.

Therefore, the flip LED provided by the invention fills the reflectivity of the first through hole in the first DBR layer through the structure of the two DBR layers, so that the brightness of the flip LED is improved.

In order to make the aforementioned objects, features and advantages of the present invention comprehensible, embodiments accompanied with figures are described in further detail below.

Referring to fig. 1, fig. 1 is a schematic structural diagram of a flip-chip LED according to an embodiment of the present invention.

The flip-chip LED includes:

a substrate 11;

an epitaxial layer structure 12 disposed on one side of the substrate 11;

a first electrode layer 13 disposed on a side of the epitaxial layer structure 12 facing away from the substrate 11;

a first DBR layer 14 disposed on a side of the first electrode layer 13 facing away from the substrate 11, wherein a plurality of first through holes are disposed on the first DBR layer 14, and the first through holes are used for exposing the first electrode layer 13;

a second electrode layer 15 disposed on a side of the first DBR layer 14 facing away from the substrate 11, wherein the second electrode layer 15 is in contact with the first electrode layer 13 through the first through hole, and a plurality of second through holes are disposed on the second electrode layer 15 and are used for exposing the first DBR layer 14;

a second DBR layer 16 disposed on a side of the second electrode layer 15 facing away from the substrate 11, the second DBR layer 16 being in contact with the first DBR layer 14 through the second via hole.

In this embodiment, in the direction perpendicular to the plane of the substrate 11, the second DBR layer 16 is in contact with the first DBR layer 14 through the second via hole, that is, the second DBR layer 16 fills the second via hole and covers the area where the first via hole is located, so as to fill the reflectivity of the first via hole in the first DBR layer 14, thereby improving the brightness of the flip-chip LED.

Further, in order to fully improve the reflectivity of the DBR layer in the flip-chip LED, in a direction perpendicular to the plane of the substrate 11, an orthogonal projection of the first through hole does not overlap an orthogonal projection of the second through hole.

Optionally, in another embodiment of the present invention, the materials of the first DBR layer 14 and the second DBR layer 16 are the same.

Optionally, in another embodiment of the present invention, the thickness of the first DBR layer 14 is 2um to 5 um;

the thickness of the second DBR layer 16 is 2um-5 um.

In this embodiment, the thickness of the first DBR layer 14 may be 2.5um, or 3.2um, or 4.7um, etc.; the thickness of the second DBR layer 16 is 2.7um or 3.1um or 4.5um etc.

Optionally, in another embodiment of the present invention, as shown in fig. 1, the flip-chip LED further includes:

a PAD layer 17 disposed on a side of the second DBR layer 16 facing away from the substrate 11; the PAD layer 17 is in contact with the second electrode layer 15.

In this embodiment, a plurality of third through holes are optionally disposed on the second DBR layer 16, the PAD layer 17 is in contact with the second electrode layer 15 through the third through holes, and the second electrode layer 15 is in contact with the first electrode layer 13 through the first through holes, so that the connection between the electrodes is realized.

Optionally, in another embodiment of the present invention, as shown in fig. 1, the epitaxial layer structure includes:

an N-type semiconductor layer 121, a multi-quantum well layer 122, and a P-type semiconductor layer 123 sequentially disposed on the substrate 11;

the epitaxial layer structure further includes:

a groove penetrating the P-type semiconductor layer 123 and the multiple quantum well layer 122, the groove for exposing the N-type semiconductor layer 121;

wherein the first electrode layer 13 is partially disposed on the N-type semiconductor layer 121 and partially disposed on the P-type semiconductor layer 123.

In this embodiment, the N-type semiconductor layer 121 includes, but is not limited to, an N-type gallium nitride layer, and the P-type semiconductor layer 123 includes, but is not limited to, a P-type semiconductor layer.

a current blocking layer 18 and a current diffusion layer 19 sequentially provided between the P-type semiconductor layer 123 and the first electrode layer 13;

wherein the current blocking layer 18 is disposed adjacent to the P-type semiconductor layer 123.

In this embodiment, the current blocking layer 18 includes, but is not limited to, a silicon oxide layer for blocking current from being vertically injected into the P-type semiconductor layer 123; the current spreading layer 19 includes, but is not limited to, an ITO transparent conductive layer for making the current injected into the P-type semiconductor layer 123 more uniform to improve the performance of the flip-chip LED.

Optionally, the thickness of the current blocking layer 18 is 2000 angstroms to 5000 angstroms.

For example, the thickness of the current blocking layer 18 is 2512 angstroms, 3500 angstroms, 4685 angstroms, or the like.

Optionally, the current spreading layer 19 has a thickness of 200 angstroms to 2000 angstroms.

For example, the thickness of the current diffusion layer 19 is 300 angstroms or 1100 angstroms or 1678 angstroms or the like.

Optionally, based on all the above embodiments of the present invention, in another embodiment of the present invention, a method for manufacturing a flip-chip LED is further provided, and referring to fig. 2, fig. 2 is a schematic flow chart of the method for manufacturing the flip-chip LED according to the embodiment of the present invention.

The manufacturing method comprises the following steps:

s101: as shown in fig. 3, a substrate 11 is provided.

S102: as shown in fig. 4, an epitaxial layer structure 12 is formed on one side of the substrate 11.

In this step, as shown in fig. 4, the epitaxial-layer structure 12 includes: an N-type semiconductor layer 121, a multi-quantum well layer 111, and a P-type semiconductor layer 123 sequentially disposed on the substrate 11.

The N-type semiconductor layer 121 includes, but is not limited to, an N-type gallium nitride layer, and the P-type semiconductor layer 123 includes, but is not limited to, a P-type semiconductor layer.

As shown in fig. 5, a mesa pattern is etched on the surface of the epitaxial layer structure 12, and a dry etching is performed on an exposed region of the mesa pattern until the N-type semiconductor layer 121 is exposed.

As shown in fig. 6, a DE pattern is further etched on the surface of the epitaxial layer structure 12, and the exposed area of the DE pattern is dry etched until the substrate 11 is exposed.

S103: a first electrode layer 13 is formed on a side of the epitaxial-layer structure 12 facing away from the substrate 11.

In this step, as shown in fig. 7, on the basis of the structure shown in fig. 6, a current blocking layer 18 is deposited on a side of the P-type semiconductor layer 123 away from the substrate 11, and a CB pattern is etched by photolithography, and a wet etching is performed on an exposed area of the CB pattern, so that a current blocking layer 18 is disposed on a side of a part of the P-type semiconductor layer 123 away from the substrate 11; the current blocking layer 18 includes, but is not limited to, a silicon oxide layer for blocking a current from being vertically injected into the P-type semiconductor layer 123.

As shown in fig. 8, on the basis of the structure shown in fig. 7, a current diffusion layer 19 is formed on the side of the current blocking layer 18 away from the substrate 11, wherein the current diffusion layer 19 includes, but is not limited to, an ITO transparent conductive layer for making the current injected into the P-type semiconductor layer 123 more uniform, so as to improve the performance of the flip-chip LED; and photoetching an ITO pattern on the current diffusion layer 19, and performing wet etching on an exposed area of the ITO pattern to finally enable the current diffusion layer 19 to cover the current barrier layer 18.

As shown in fig. 9, on the basis of the structure shown in fig. 8, an electrode pattern is photoetched on the surface of the current diffusion layer 19, and a first electrode layer 13 is deposited; the first electrode layer 13 is partially disposed on the N-type semiconductor layer 121 and partially disposed on the current diffusion layer 19.

S104: as shown in fig. 10, a first DBR layer 14 is formed on a side of the first electrode layer 13 facing away from the substrate 11, and a plurality of first through holes 141 are formed in the first DBR layer 14, and the first through holes 141 are used for exposing the first electrode layer 13.

S105: as shown in fig. 11, a second electrode layer 15 is formed on a side of the first DBR layer 14 facing away from the substrate 11, the second electrode layer 15 is in contact with the first electrode layer 13 through the first through holes 141, a plurality of second through holes 151 are provided in the second electrode layer 15, and the second through holes 151 are used for exposing the first DBR layer 14.

S106: as shown in fig. 12, a second DBR layer 16 is formed on the side of the second electrode layer 15 facing away from the substrate 11, and the second DBR layer 16 is in contact with the first DBR layer 14 through the second via hole 151.

In this embodiment, the flip-chip LED fills the reflectivity of the first via 141 in the first DBR layer 14 by the two DBR layers, thereby improving the brightness of the flip-chip LED.

Optionally, in another embodiment of the present invention, referring to fig. 13, fig. 13 is a schematic flow chart of another method for manufacturing a flip-chip LED according to the embodiment of the present invention.

The manufacturing method further comprises the following steps:

s107: as shown in fig. 14 and 1, a PAD layer 17 is formed on a side of the second DBR layer 16 facing away from the substrate 11; the PAD layer 17 is in contact with the second electrode layer 15.

In this embodiment, a plurality of third vias 161 are disposed on the optional second DBR layer 16, the PAD layer 17 contacts the second electrode layer 15 through the third vias 161, and the second electrode layer 15 contacts the first electrode layer 13 through the first vias 141, so as to achieve connection between the electrodes.

It should be noted that the coverage area of the second DBR layer 16 may be determined according to actual circumstances, and may only cover the second via hole 151, or may cover other areas in a large area.

The flip-chip LED and the manufacturing method thereof provided by the present invention are described in detail above, and the principle and the implementation of the present invention are explained in the present document by applying specific examples, and the description of the above examples is only used to help understanding the method and the core idea of the present invention; meanwhile, for a person skilled in the art, according to the idea of the present invention, there may be variations in the specific embodiments and the application scope, and in summary, the content of the present specification should not be construed as a limitation to the present invention.

It should be noted that, in the present specification, the embodiments are all described in a progressive manner, each embodiment focuses on differences from other embodiments, and the same and similar parts among the embodiments may be referred to each other. The device disclosed by the embodiment corresponds to the method disclosed by the embodiment, so that the description is simple, and the relevant points can be referred to the method part for description.

It is further noted that, herein, relational terms such as first and second, and the like may be used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Also, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include or include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising an … …" does not exclude the presence of other identical elements in a process, method, article, or apparatus that comprises the element.

The previous description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the invention. Thus, the present invention is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A flip-chip LED, comprising:

a substrate;

an epitaxial layer structure disposed on one side of the substrate;

2. The flip-chip LED of claim 1, wherein an orthographic projection of the first via does not overlap an orthographic projection of the second via in a direction perpendicular to a plane of the substrate.

3. The flip-chip LED of claim 1, wherein the first DBR layer and the second DBR layer are the same material.

4. The flip-chip LED of claim 1, wherein the first DBR layer has a thickness of 2um-5 um;

the thickness of the second DBR layer is 2um-5 um.

5. The flip LED of claim 1, further comprising:

6. The flip-chip LED of claim 1, wherein the epitaxial layer structure comprises:

the epitaxial layer structure further includes:

7. The flip LED of claim 6, further comprising:

8. The flip-chip LED of claim 7, wherein the current blocking layer has a thickness of 2000-5000 angstroms.

9. The flip-chip LED of claim 7, wherein the current spreading layer has a thickness of 200-2000 angstroms.

10. A method for manufacturing a flip-chip LED, the method comprising:

providing a substrate;

forming an epitaxial layer structure on one side of the substrate;