阅读说明：本技术 Led芯片及其制备方法 (LED chip and preparation method thereof ) 是由 王思博 李冬梅 廖汉忠 于 2021-10-14 设计创作，主要内容包括：本发明涉及半导体制造技术领域,具体而言,涉及一种LED芯片及其制备方法。包括：衬底、外延层、电流阻挡层、电流扩展层、第一P型电极、第一N型电极、第一绝缘层、第二P型电极、第二N型电极、第二绝缘层、第三P型电极、第三N型电极、P型焊盘和N型焊盘。该LED芯片通过改进倒装芯片的电极设计,通过增加第三N型电极和第三P型电极,且第三N型电极与P型焊盘在空间上无任何重叠,同理第三P型电极与N型焊盘在空间上也无任何重叠,二者无接触可能,不存在因为任何原因导致氧化硅断裂,而导致极性不同的P、N型电极互连而发生漏电失效的问题,从而提高了芯片的可靠性。(The invention relates to the technical field of semiconductor manufacturing, in particular to an LED chip and a preparation method thereof. The method comprises the following steps: the device comprises a substrate, an epitaxial layer, a current blocking layer, a current expansion layer, a first P-type electrode, a first N-type electrode, a first insulating layer, a second P-type electrode, a second N-type electrode, a second insulating layer, a third P-type electrode, a third N-type electrode, a P-type bonding pad and an N-type bonding pad. According to the LED chip, by improving the electrode design of the flip chip, the third N-type electrode and the third P-type electrode are added, the third N-type electrode and the P-type bonding pad do not overlap in space, and similarly, the third P-type electrode and the N-type bonding pad do not overlap in space, the third N-type electrode and the P-type bonding pad do not have contact possibility, and the problem of leakage failure caused by interconnection of P, N-type electrodes with different polarities due to silicon oxide breakage caused by any reason is solved, so that the reliability of the chip is improved.)

An LED chip, comprising:

a substrate;

the epitaxial wafer with the PN step comprises an N-type semiconductor layer, a light emitting layer and a P-type semiconductor layer;

at least one first P-type electrode which is positioned on the PN step and is electrically connected with the P-type semiconductor layer;

at least one first N-type electrode, which is positioned on the N-type semiconductor layer and is electrically connected with the N-type semiconductor layer;

a first insulating layer covering the first N-type electrode, the PN step, the first P-type electrode, and the N-type semiconductor layer, and provided with a plurality of first through holes and a plurality of second through holes;

the second P-type electrode is arranged on the first insulating layer and is electrically connected with the first P-type electrode through the first through hole;

the second N-type electrode is arranged on the first insulating layer and is electrically connected with the first N-type electrode through the second through hole;

a second insulating layer covering the second P-type electrode, the second N-type electrode, and the first insulating layer, and provided with a plurality of third through holes and a plurality of fourth through holes;

the third P-type electrode is arranged on the second insulating layer and is electrically connected with the second P-type electrode through the third through hole;

the third N-type electrode is arranged on the second insulating layer and is electrically connected with the second N-type electrode through the fourth through hole;

the P-type bonding pad is arranged on the third P-type electrode and is electrically connected with the third P-type electrode;

and the N-type bonding pad is arranged on the third N-type electrode and is electrically connected with the third N-type electrode.

2. The LED chip of claim 1, wherein at least a third N-type electrode is disposed between said N-type pad and said second P-type electrode in a vertical cross-sectional view;

and/or at least the third P-type electrode is arranged between the P-type bonding pad and the second N-type electrode.

3. The LED chip of claim 1, wherein the second layer directly under the N pad is a second insulating layer and/or a second N-type electrode;

preferably, a projection on a horizontal plane of the N-pad is located within a projection on a horizontal plane of the third N-type electrode.

4. The LED chip of claim 1, further comprising a third insulating layer covering said third P-type electrode and said third N-type electrode;

a plurality of fifth through holes and sixth through holes are formed in the third insulating layer;

the P-type welding disc is electrically connected with the third P-type electrode through the fifth through hole, and the N-type welding disc is electrically connected with the third N-type electrode through the sixth through hole.

5. The LED chip of claim 1, wherein the distance between said third P-type electrode and said third N-type electrode is greater than 15 μ ι η;

and/or; the sum of the areas of the third P-type electrode and the third N-type electrode accounts for 50% -75% of the area of the whole LED chip;

and/or; the sum of the areas of the P-type bonding pad and the N-type bonding pad accounts for 30% -55% of the area of the whole LED chip.

6. The LED chip of claim 1, wherein the shortest distance between the second P-type electrode region and the side of the PN step is D₁The shortest distance between the third N-type electrode and the side surface of the PN step is D₂The shortest distance between the N-type bonding pad and the side surface of the PN step is D₃And D is₁＜D₂＜D₃；

Preferably, said D₁＞5μm，D₂＞8μm，D₃＞15μm。

7. The LED chip of claim 1, wherein a plurality of said first P-type electrodes are spaced on said PN step; the first N-type electrodes are arranged on the N-type semiconductor layer at intervals;

and/or;

one or more second N-type electrodes are respectively arranged with a gap from the second P-type electrode, wherein part of the second N-type electrodes are arranged on the PN steps.

8. The LED chip of claim 1, wherein said first insulating layer is silicon oxide and DBR reflective layer;

preferably, the first insulating layer has a thickness of 2 to 7 μm, and more preferably 3.5 to 5.5 μm.

9. The LED chip of claim 4, wherein the second insulating layer and/or the third insulating layer comprises at least one of silicon oxide, silicon nitride, and silicon oxynitride;

preferably, the thickness of the second insulating layer and/or the third insulating layer is

10. The method for preparing an LED chip according to any one of claims 1 to 9, comprising the steps of:

(a) providing a substrate, and depositing an N-type semiconductor layer, a light emitting layer and a P-type semiconductor layer on the substrate in sequence to form an epitaxial layer;

(b) depositing SiO on the epitaxial layer₂Obtaining a current barrier layer by photoetching, then depositing to obtain a current expansion layer, and obtaining a PN step by etching;

(c) depositing a plurality of first P-type electrodes and a plurality of first N-type electrodes on the surface of the chip in an interval distribution manner, and then depositing a first insulating layer;

(d) respectively obtaining a first through hole and a second through hole by photoetching above the first P-type electrode and the first N-type electrode, depositing a second P-type electrode at the first through hole, and depositing a second N-type electrode at the second through hole, wherein the second P-type electrode and the second N-type electrode are isolated from each other;

(e) depositing a second insulating layer, photoetching the upper parts of the second P-type electrode and the second N-type electrode to respectively obtain a third through hole and a fourth through hole, depositing a third P-type electrode at the third through hole, depositing a third N-type electrode at the fourth through hole, isolating the third P-type electrode and the third N-type electrode from each other, and extending the second P-type electrode to the lower part of the third N-type electrode;

(f) and depositing a third insulating layer, photoetching the upper parts of the third P-type electrode and the third N-type electrode to respectively obtain a fifth through hole and a sixth through hole, depositing a P-type bonding pad at the fifth through hole, and depositing an N-type bonding pad at the sixth through hole.

Technical Field

The invention relates to the technical field of semiconductor manufacturing, in particular to an LED chip and a preparation method thereof.

Background

As a new generation light source, LEDs are widely used in the technical fields of illumination, display, backlight, and even optical communication. Flip chips have become more and more popular with users as a product with higher light efficiency. The manufacturing process of the flip chip has more structures and complex process. Therefore, there are higher demands and challenges for reliability.

In a conventional ODR structure, as shown in FIG. 1, a P-type metal electrode metal layer extends to below an N-type bonding pad, and SiO is arranged between the P-type metal electrode metal layer and the N-type bonding pad₂The insulating layers are isolated from each other, forming regions as indicated by the dashed boxes. When the insulating layer is broken or cracked due to some reasons, the P-type electrode and the N-type pad can be communicated, electric leakage is caused, and the reliability of the conventional LED is reduced when the LED is used.

In view of the above, the present invention is particularly proposed.

Disclosure of Invention

The first purpose of the invention is to provide an LED chip, compared with the conventional ODR structure, by improving the electrode design of a flip chip and adopting a double-layer homogeneous electrode, the problem of chip failure caused by solder paste electromigration or insulation layer fracture is avoided, and thus the reliability of the chip is improved.

The second purpose of the present invention is to provide the method for manufacturing the LED chip as described above, in which the third N-type electrode and the third P-type electrode are added, and the third N-type electrode and the P-type pad do not overlap in space, and similarly, the third P-type electrode and the N-type pad do not overlap in space, and there is no possibility of contact therebetween, and there is no problem of leakage failure due to interconnection of P, N type electrodes with different polarities because of the fracture of the insulating layer caused by any reason.

In order to achieve the above purpose of the present invention, the following technical solutions are adopted:

the present invention provides an LED chip, comprising:

a substrate;

the epitaxial wafer with the PN step comprises an N-type semiconductor layer, a light emitting layer and a P-type semiconductor layer;

at least one first P-type electrode which is positioned on the PN step and is electrically connected with the P-type semiconductor layer;

at least one first N-type electrode, which is positioned on the N-type semiconductor layer and is electrically connected with the N-type semiconductor layer;

a first insulating layer covering the first N-type electrode, the PN step, the first P-type electrode, and the N-type semiconductor layer, and provided with a plurality of first through holes and a plurality of second through holes;

the second P-type electrode is arranged on the first insulating layer and is electrically connected with the first P-type electrode through the first through hole;

the second N-type electrode is arranged on the first insulating layer and is electrically connected with the first N-type electrode through the second through hole;

a second insulating layer covering the second P-type electrode, the second N-type electrode, and the first insulating layer, and provided with a plurality of third through holes and a plurality of fourth through holes;

the third P-type electrode is arranged on the second insulating layer and is electrically connected with the second P-type electrode through the third through hole;

the third N-type electrode is arranged on the second insulating layer and is electrically connected with the second N-type electrode through the fourth through hole;

the P-type bonding pad is arranged on the third P-type electrode and is electrically connected with the third P-type electrode;

and the N-type bonding pad is arranged on the third N-type electrode and is electrically connected with the third N-type electrode.

In a preferred embodiment of the present invention, in a vertical cross-sectional view, at least a third N-type electrode is disposed between the N-type pad and the second P-type electrode;

and/or at least the third P-type electrode is arranged between the P-type bonding pad and the second N-type electrode.

In a preferred embodiment of the present invention, the second layer directly under the N pad is a second insulating layer and/or a second N-type electrode;

preferably, a projection on a horizontal plane of the N-pad is located within a projection on a horizontal plane of the third N-type electrode.

In a preferred embodiment of the present invention, the LED chip further includes a third insulating layer, and the third insulating layer covers the third P-type electrode and the third N-type electrode;

a plurality of fifth through holes and sixth through holes are formed in the third insulating layer;

the P-type welding disc is electrically connected with the third P-type electrode through the fifth through hole, and the N-type welding disc is electrically connected with the third N-type electrode through the sixth through hole.

In a preferred embodiment of the present invention, the distance between the third P-type electrode and the third N-type electrode is greater than 15 μm;

and/or; the sum of the areas of the third P-type electrode and the third N-type electrode accounts for 50% -75% of the area of the whole LED chip;

and/or; the sum of the areas of the P-type bonding pad and the N-type bonding pad accounts for 30% -55% of the area of the whole LED chip.

In a preferred embodiment of the present invention, the shortest distance between the second P-type electrode region and the side surface of the PN step is D₁The shortest distance between the third N-type electrode and the side surface of the PN step is D₂The shortest distance between the N-type bonding pad and the side surface of the PN step is D₃And D is₁＜D₂＜D₃；

Preferably, said D₁＞5μm，D₂＞8μm，D₃＞15μm。

In a preferred embodiment of the present invention, a plurality of the first P-type electrodes are disposed on the PN step at intervals; the first N-type electrodes are arranged on the N-type semiconductor layer at intervals.

In a preferred embodiment of the present invention, a gap is formed between each of the one or more second N-type electrodes and the second P-type electrode, wherein a portion of the second N-type electrode is located above the PN step.

In a preferred embodiment of the present invention, the first insulating layer is silicon oxide and a DBR reflective layer;

preferably, the first insulating layer has a thickness of 2 to 7 μm, and more preferably 3.5 to 5.5 μm.

In a preferred embodiment of the present invention, the second insulating layer and/or the third insulating layer includes at least one of silicon oxide, silicon nitride, and silicon oxynitride;

preferably, the thickness of the second insulating layer and/or the third insulating layer is

The preparation method of the LED chip provided by the invention comprises the following steps:

(a) providing a substrate, and depositing an N-type semiconductor layer, a light emitting layer and a P-type semiconductor layer on the substrate in sequence to form an epitaxial layer;

(b) depositing SiO on the epitaxial layer₂Obtaining a current barrier layer by photoetching, then depositing to obtain a current expansion layer, and obtaining a PN step by etching;

(c) depositing a plurality of first P-type electrodes and a plurality of first N-type electrodes on the surface of the chip in an interval distribution manner, and then depositing a first insulating layer;

(d) respectively obtaining a first through hole and a second through hole by photoetching above the first P-type electrode and the first N-type electrode, depositing a second P-type electrode at the first through hole, and depositing a second N-type electrode at the second through hole, wherein the second P-type electrode and the second N-type electrode are isolated from each other;

(e) depositing a second insulating layer, photoetching the upper parts of the second P-type electrode and the second N-type electrode to respectively obtain a third through hole and a fourth through hole, depositing a third P-type electrode at the third through hole, depositing a third N-type electrode at the fourth through hole, isolating the third P-type electrode and the third N-type electrode from each other, and extending the second P-type electrode to the lower part of the third N-type electrode;

(f) and depositing a third insulating layer, photoetching the upper parts of the third P-type electrode and the third N-type electrode to respectively obtain a fifth through hole and a sixth through hole, depositing a P-type bonding pad at the fifth through hole, and depositing an N-type bonding pad at the sixth through hole.

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

compared with the conventional ODR structure, the LED chip has the advantages that the electrode design of the flip chip is improved, the third N-type electrode and the third P-type electrode are added, the third N-type electrode and the P-type bonding pad do not overlap in space, the third P-type electrode and the N-type bonding pad do not overlap in space, the third N-type electrode and the N-type bonding pad do not contact with each other, the problem that the P, N-type electrodes with different polarities are interconnected to cause leakage failure due to silicon oxide breakage caused by any reason is solved, and the reliability of the chip is improved.

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, and it is obvious that the drawings in the following description are some embodiments of the present invention, and other drawings can be obtained by those skilled in the art without creative efforts.

FIG. 1 is a cross-sectional view of a conventional LED flip chip with an ODR structure;

fig. 2 is a schematic plan view of an LED chip according to an embodiment of the present invention;

fig. 3 is a cross-sectional view of the LED chip of the embodiment of the invention cut along the mode a of fig. 1;

fig. 4 is a cross-sectional view of the LED chip provided in the embodiment of the present invention, cut along the line B of fig. 1;

fig. 5 is a schematic distance diagram of a third P-type electrode, a third N-type electrode, a fourth P-type electrode, and a fourth N-type electrode of an LED chip according to an embodiment of the invention;

fig. 6 is a schematic plan view of an LED chip according to another embodiment of the present invention.

Reference numerals:

100-a substrate; 200-an epitaxial layer; 210-N type semiconductor layer;

211-PN step; 220-a light emitting layer; a 230-P type semiconductor layer;

300-a current blocking layer; 400-current spreading layer; 510-a first P-type electrode;

511-a first via; 520-a first N-type electrode; 521-a second through hole;

600-a first insulating layer; 710-a second P-type electrode; 711-third via;

720-a second N-type electrode; 721-fourth via; 800-a second insulating layer;

910-a third P-type electrode; 920-a third N-type electrode; 1000-NP padset;

1100-P type pad; 1200-N type pads; 1300-third insulating layer.

Detailed Description

The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings and the detailed description, but those skilled in the art will understand that the following described embodiments are some, not all, of the embodiments of the present invention, and are only used for illustrating the present invention, and should not be construed as limiting the scope of the present invention. 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. The examples, in which specific conditions are not specified, were conducted under conventional conditions or conditions recommended by the manufacturer. The reagents or instruments used are not indicated by the manufacturer, and are all conventional products available commercially.

The agent or apparatus is not indicated by the manufacturer, and is a conventional product available by commercial purchase.

In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings, and are only for convenience of description and simplicity of description, but do not indicate or imply that the device or element being referred to must have a particular orientation, be constructed and operated in a particular orientation, and thus, should not be construed as limiting the present invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance.

In the description of the present invention, it should be noted that, unless otherwise explicitly specified or limited, the terms "mounted," "connected," and "connected" are to be construed broadly, e.g., as meaning either a fixed connection, a removable connection, or an integral connection; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meanings of the above terms in the present invention can be understood in specific cases to those skilled in the art.

Fig. 2 is a schematic plan view of an LED chip according to an embodiment of the present invention; fig. 3 is a cross-sectional view of the LED chip provided in the embodiment of the present invention cut along the mode a of fig. 1, and fig. 4 is a cross-sectional view of the LED chip provided in the embodiment of the present invention cut along the mode B of fig. 1. As shown in fig. 2 and 3, the LED chip provided by the embodiment of the present invention includes:

a substrate 100;

an epitaxial wafer having a PN step 211, the epitaxial wafer including an N-type semiconductor layer 210, a light emitting layer 220, and a P-type semiconductor layer 230;

at least one first P-type electrode 510 located on the PN step 211 and electrically connected to the P-type semiconductor layer 230;

at least one first N-type electrode 520 on the N-type semiconductor layer 210 and electrically connected to the N-type semiconductor layer 210;

a first insulating layer 600 covering the first N-type electrode 520, the PN step 211, the first P-type electrode 510, and the N-type semiconductor layer 210, and provided with a plurality of first through holes 511 and a plurality of second through holes 521;

a second P-type electrode 710 disposed on the first insulating layer 600 and electrically connected to the first P-type electrode 510 through the first via 511;

a second N-type electrode 720 disposed on the first insulating layer 600 and electrically connected to the first N-type electrode 520 through the second via 521;

a second insulating layer 800 covering the second P-type electrode 710, the second N-type electrode 720, and the first insulating layer 600, and provided with a plurality of third through holes 711 and a plurality of fourth through holes 721;

a third P-type electrode 910 disposed on the second insulating layer 800 and electrically connected to the second P-type electrode 710 through the third via 711;

a third N-type electrode 920 disposed on the second insulating layer 800 and electrically connected to the second N-type electrode 720 through the fourth through hole 721;

a P-type pad 1100 disposed on the third P-type electrode 910 and electrically connected to the third P-type electrode 910;

the N-type pad 1200 is disposed on the third N-type electrode 920 and electrically connected to the third N-type electrode 920.

The epitaxial layer 200 comprises a PN step 211, the upper step surface of the PN step 211 is a P-type semiconductor layer 230, the lower step surface is an N-type semiconductor layer 210, and the upper step surface and the lower step surface are connected to form the side surface of the PN step 211;

in the process of designing the LED chip, by adding the third N-type electrode 920 and the third P-type electrode 910, and without any overlap between the third N-type electrode 920 and the P-type pad 1100 in the vertical space or any other direction, similarly, there is no overlap between the third P-type electrode 910 and the N-type pad 1200 in the vertical space or any other direction, and there is no possibility of contact between the third N-type electrode 920 and the P-type pad, and there is no problem of leakage failure due to interconnection of P, N type electrodes with different polarities caused by the breakage of the insulating layer, thereby improving the reliability of the chip.

Further, the substrate 100 may be a sapphire substrate 100, but is not limited thereto. In addition, patterned substrate 100 may also be selected.

Further, the material of the N-type semiconductor layer 210 may be N-type doped gallium nitride, and the material of the P-type semiconductor layer 230 may be P-type doped gallium nitride, but is not limited to these two semiconductor types.

Further, the light emitting layer 220 includes quantum wells and quantum barriers alternately stacked, but is not limited thereto. The light emitting layer 220 includes, but is not limited to, a red light emitting layer 220, a yellow light emitting layer 220, a green light emitting layer 220, or a blue light emitting layer 220. The quantum well includes, but is not limited to, an InGaN quantum well or an AlInGaN quantum well.

Further, the current blocking layer 300 includes, but is not limited to, SiO₂。

Further, the current spreading layer 400 includes, but is not limited to, one of ITO, ZITO, ZIO, GIO, ZTO, FTO, AZO, and GZO.

Further, the current spreading layer 400 includes a thickness ofFor example, can be Further, the current spreading layer 400 may be deposited by magnetron sputtering or evaporation.

In a preferred embodiment of the present invention, the current spreading layer 400 occupies 70% to 90% of the area of the LED chip.

Further, according to the patterned photoresist feature, a plurality of first P-type electrodes 510 and a plurality of first N-type electrodes 520 are deposited on the surface of the chip, and the first P-type electrodes and the first N-type electrodes 520 are preferably Finger-shaped electrodes (Finger electrodes). The first P-type electrode 510 and the first N-type electrode 520 are isolated from each other and have an isolation trench. Further preferably, the electrode structures of the first P-type electrode 510 and the first N-type electrode 520 may adopt electrode structures of metals such as Cr/Al/Ti/Ni/Pt/Au, and may be a single metal layer or a composite layer of several metals.

In a preferred embodiment of the present invention, in order to improve the stability of the LED chip in use, the second electrode layer and the pad layer are ensured to be sandwiched therebetween without contact, and the second electrode layer and the pad layer are ensured to have the same polarity as the pad layer. Specifically, at least a third N-type electrode 920 is disposed between the N-type pad 1200 and the second P-type electrode 710; and/or at least the third P-type electrode 910 is disposed between the P-type pad 1100 and the second N-type electrode 720. Further, the second layer directly under the N-pad is the second insulating layer 800 and/or the second N-type electrode 720.

Preferably, the projection of the horizontal plane of the N-pad is located within the projection of the horizontal plane of the third N-type electrode 920, so as to ensure that there is no spatial overlap between the third N-type electrode 920 and the P-type pad 1100, and similarly, there is no spatial overlap between the third P-type electrode 910 and the N-type pad 1200, and there is no possibility of contact between the third N-type electrode and the P-type pad, and there is no problem of leakage failure due to interconnection of P, N type electrodes with different polarities because of silicon oxide breakage caused by any reason, thereby improving the reliability of the chip.

In a preferred embodiment of the present invention, an insulating layer may further be coated outside a third electrode layer, and the LED chip further includes a third insulating layer 1300, where the third insulating layer 1300 covers the third P-type electrode 910 and the third N-type electrode 920; a plurality of fifth through holes and sixth through holes are formed in the third insulating layer 1300; the P-type pad 1100 is electrically connected to the third P-type electrode 910 through the fifth through hole, and the N-type pad 1200 is electrically connected to the third N-type electrode 920 through the sixth through hole.

In a preferred embodiment of the present invention, one or more second N-type electrodes 720 have a gap with the second P-type electrode 710, wherein a portion of the second N-type electrodes 720 is located above the PN step 211.

In a preferred embodiment of the present invention, as shown in fig. 5, the distance between the third P-type electrode 910 and the third N-type electrode 920 is greater than 15 μm in P3;

the sum of the areas of the third P-type electrode 910 and the third N-type electrode 920 occupies 50% to 75%, for example, 50%, 60%, 70%, 75% of the area of the entire LED chip.

The sum of the areas of the P-type pad 1100 and the N-type pad 1200 occupies 30% to 55%, for example, 30%, 40%, 45%, 55% of the area of the entire LED chip.

In a preferred embodiment of the present invention, the shortest distance between the second P-type electrode 710 region and the side surface of the PN step 211 is D₁The shortest distance between the third N-type electrode 920 and the side surface of the PN step 211 is D₂The shortest distance between the N-type pad 1200 and the side surface of the PN step 211 is D₃And D is₁＜D₂＜D₃；

Preferably, said D₁＞5μm，D₂＞8μm，D₃＞15μm。

Further, a plurality of the first P-type electrodes 510 are disposed on the PN step 211 at intervals; the first N-type electrodes 520 are disposed on the N-type semiconductor layer 210 at intervals, and further, one or more second N-electrode regions are disposed in the second N-electrode region, wherein a gap is formed between each of the second N-electrode regions and the second P-electrode region, and a portion of the second N-electrode region is located above the PN step 211.

In a preferred embodiment of the present invention, the first insulating layer 600 is silicon oxide and a DBR reflective layer.

Preferably, the DBR reflective layer includes, but is not limited to, SiO₂、TiO₂And Ti₃O₅Any one or more of them, e.g. SiO₂And/or TiO₂Or is, SiO₂And/or Ti₃O₅. Further, the DBR reflective layers may be alternately deposited of SiO₂And Ti₃O₅And (4) forming.

Further, a first through hole 511 penetrating through the first P-type electrode 510 and a second through hole 521 penetrating through the first N-type electrode 520 are etched on the DBR reflective layer, a second P-type electrode 710 is formed at the first through hole 511 by electron beam evaporation, and a second N-type electrode 720 is formed at the second through hole 521 by electron beam evaporation. The second P-type electrode 710, the second N-type electrode 720 and the DBR reflective layer form an ODR structure, so that the reflectivity of the layer of electrodes is between 60% and 95%, and the angle of the layer of metal electrodes is required to be 30-75 °.

Preferably, the first insulating layer 600 has a thickness of 2 μm to 7 μm, for example, 2 μm, 3 μm, 4 μm, 5 μm, 6 μm, 7 μm, and more preferably has a thickness of 3.5 μm to 5.5 μm.

In a preferred embodiment of the present invention, the second insulating layer 800 and/or the third insulating layer 1300 includes at least one of silicon oxide, silicon nitride, and silicon oxynitride; such as silicon oxide and/or silicon nitride, or alternatively, silicon nitride and/or silicon oxynitride.

Preferably, the thickness of the second insulation layer 800 and/or the third insulation layer 1300 isFor example, is

Further, the P-type pad 1100 and the N-type pad 1200 may use one or a combination of several metal layers of Ti, Al, Pt, Ni, and Au metals. Further, Al has a thickness ofThickness of Pt isThickness of Ti ofThickness of Ni ofThickness of Au of

Further, the P-type pad 1100 and the N-type pad 1200 may be Bump electrodes, and the electrode component is Sn. Furthermore, the bump electrode can be made by printing, electroplating or evaporation. The height of the Bump electrode is more than or equal to 5 microns, and the height of the solder paste is more than or equal to 20 microns;

in a preferred embodiment of the present invention, the sum of the areas of the P-type pad 1100 and the N-type pad 1200 occupies 30% to 55%, for example, 50%, 60%, 70%, 75% of the area of the entire LED chip.

In a preferred embodiment of the present invention, a sum of areas of the third P-type electrode 910 and the third N-type electrode 920 is greater than a sum of areas of the P-type pad 1100 and the N-type pad 1200.

The embodiment of the invention also provides a specific preparation method of the LED chip, which comprises the following steps:

(1) providing a substrate 100, and sequentially manufacturing an N-type semiconductor layer 210, a light emitting layer 220 and a P-type semiconductor layer 230 on the substrate 100 to form an epitaxial layer 200;

(2) depositing SiO on the epitaxial layer 200₂And obtaining the current barrier layer 300 by yellow light and etching, and depositing the thickness on the substrate by a magnetron sputtering mode or evaporationObtaining a current expansion layer 400 by using the ITO film, obtaining a PN step 211 by etching, and forming an isolation groove by deep etching;

(3) performing yellow light according to the pattern to form a photoresist morphology, depositing a first P-type electrode 510 and a first N-type electrode 520 on the surface of the chip in an interval distribution manner, and then depositing a first insulating layer 600;

(4) respectively obtaining a first through hole 511 and a second through hole 521 by photoetching above the first P-type electrode 510 and the first N-type electrode 520, and depositing a second P-type electrode 710 at the first through hole 511, wherein the first through hole 511 and the second through hole 521 are separated from each other without any extending and crossing; depositing a second N-type electrode 720 at the second via 521, wherein the second P-type electrode 710 and the second N-type electrode 720 are isolated from each other, the second P-type electrode 710 is communicated with the first P-type electrode 510 through a first passage, the second N-type electrode 720 is communicated with the first N-type electrode 520 through a first passage, so that the electrode reflectivity is 60-95%, and the angle of the layer of metal electrode is required to be 30-75 °;

(5) depositing a second insulating layer 800 having a thickness ofRespectively obtaining a third through hole 711 and a fourth through hole 721 above the second P-type electrode 710 and the second N-type electrode 720 by adopting yellow light and ICP dry etching, depositing a third P-type electrode 910 at the third through hole 711, and depositing a third N-type electrode 920 at the fourth through hole 721, so that the electrode reflectivity is 60-95%, and the angle of the metal electrode is required to be 30-75 degrees to ensure subsequent film covering;

the third P-type electrode 910 and the third N-type electrode 920 are isolated from each other, the second P-type electrode 710 extends to the lower side of the third N-type electrode 920, and the front chip of the second insulating layer 800 has no fracture part except at the third through hole 711 and the fourth through hole 721, so that the upper layer of the third N-type electrode 920 is separated from the lower layer of the second P-type electrode 710 extending to the lower side of the third N-type electrode 920, and a leakage path is cut off;

(6) depositing a third insulating layer 1300, and photoetching above the third P-type electrode 910 and the third N-type electrode 920 to obtain a fifth through hole and a sixth through hole respectively, wherein the etching angle is required to be 20-80 degrees, depositing a P-type bonding pad 1100 at the fifth through hole, and depositing an N-type bonding pad 1200 at the sixth through hole.

(7) And performing polishing, scribing and the like to form core particles, wherein the polishing thickness is in a range of 80 to 300 μm.

Therefore, the flip-chip LED chip can be obtained, the P-type bonding pad 1100 is interconnected with the third P-type electrode 910 through the fifth through hole of the third insulating layer 1300, the N-type bonding pad 1200 is interconnected with the third N-type electrode 920 through the sixth through hole of the third insulating layer 1300, meanwhile, the surface of the fourth P-type bonding pad 1100 facing the substrate 100 is only connected with the third P-type electrode 910, and the surface of the N-type bonding pad 1200 facing the substrate 100 is only connected with the third N-type electrode 920. The P-type pad 1100 has no surface in direct or indirect contact with the third N-type electrode 920, and no extension crossing, as viewed in the lateral and longitudinal directions. The same applies to the N-type pad 1200 and the third P-type electrode 910. Therefore, the problem of leakage failure caused by interconnection of PN type electrodes with different polarities due to silicon oxide breakage does not exist.

In another embodiment of the present invention, a schematic structural diagram of the LED chip is shown in fig. 6, where an N-type pad 1200 and a P-type pad 1100 are in the form of two pads, respectively, and each pad is 688 μm 244 μm, as shown in an NP pad set 1000.

While particular embodiments of the present invention have been illustrated and described, it will be appreciated that the above embodiments are merely illustrative of the technical solution of the present invention and are not restrictive; those of ordinary skill in the art will understand that: modifications may be made to the above-described embodiments, or equivalents may be substituted for some or all of the features thereof without departing from the spirit and scope of the present invention; the modifications or the substitutions do not make the essence of the corresponding technical solutions depart from the scope of the technical solutions of the embodiments of the present invention; it is therefore intended to cover in the appended claims all such alternatives and modifications that are within the scope of the invention.