CN110739380A - Micro light-emitting element and display device - Google Patents

Abstract

The present invention provides a micro-light-emitting element, including an element layer, a first electrode and a second electrode. The element layer includes a body and a protruding structure arranged on the body. The first electrode is electrically connected to the element layer. The second electrode is electrically connected to the element layer. The first electrode, the second electrode and the protruding structure are arranged on the same side of the body. The protruding structure is located between the first electrode and the second electrode. The connection line between the first electrode and the second electrode passes through the protruding structure. The body has a surface. The protruding structure has a first height on the surface. Either the first electrode or the second electrode has a second height on the surface. The first height is H1, the second height is H2, and 0.8≤H1/H2≤1.2. A display device having multiple micro-light-emitting elements is also proposed.

Description

Micro light-emitting element and display device

technical field

The present invention relates to a light-emitting element and a display device, in particular to a micro-light-emitting element and a display device.

Background technique

With the evolution of optoelectronic technology, traditional incandescent light bulbs and fluorescent tubes have been gradually replaced by a new generation of solid-state light sources such as light-emitting diodes (LEDs), which have advantages such as long life, small size, and high shock resistance. Therefore, it has been widely used as a light source in household lighting and various equipment. In addition to the backlight modules of liquid crystal displays and household lighting fixtures that have widely used light-emitting diodes as light sources, in recent years, the application fields of light-emitting diodes have expanded to road lighting, large outdoor signboards, traffic lights, UV curing and related fields. Light-emitting diodes have become one of the main projects to develop light sources with both power saving and environmental protection functions.

In the field of LED, a new technology called micro light emitting diode (micro light emitting diode) has been developed that reduces the size of the original light emitting diode chip by a lot. Compared with organic light emitting diode (OLED) displays currently on the market, miniature light emitting diodes are expected to become the mainstream of next-generation display technology due to their longer service life and lower production costs, and thus attract many manufacturers. Actively engage. However, the miniaturization of the light-emitting diode also shortens the distance between the two electrode pads. During the bonding process of transferring to the electronic device, the conductive solders respectively connecting the two electrode pads are easily short-circuited due to overflow, resulting in inconvenience. The chance of a good product will increase.

SUMMARY OF THE INVENTION

The invention provides a miniature light-emitting element with high transfer success rate.

The present invention provides a display device with high production yield.

An embodiment of the present invention provides a micro light-emitting element, which includes an element layer, a first electrode and a second electrode. The element layer includes a body and a protruding structure disposed on the body. The body has a surface. The first electrode is electrically connected to the element layer. The second electrode is electrically connected to the element layer. The first electrode, the second electrode and the protruding structure are arranged on the same side of the body. The protruding structure is located between the first electrode and the second electrode, and the connection line between the first electrode and the second electrode passes through the protruding structure. The protruding structure has a first height on the surface. Either one of the first electrode and the second electrode has a second height on the surface. The first height is H1, the second height is H2, and 0.8≤H1/H2≤1.2.

An embodiment of the present invention provides a display device including a backplane, a first bonding pad, a second bonding pad, and the above-mentioned micro light-emitting element. The first bonding pad and the second bonding pad are disposed on the backplane. The first electrode of the micro light-emitting element is electrically connected to the backplane through the first bonding pad. The second electrode of the micro light-emitting element is electrically connected to the backplane through the second bonding pad. The first bond pad and the second bond pad are separated from each other.

In an embodiment of the present invention, the maximum length of the protruding structure of the micro light-emitting element is L1. The distance between the first electrode and the second electrode is S1, and 0.8≤L1/S1≤1.

In an embodiment of the present invention, the maximum length of the element layer of the micro light-emitting element is L2, and L1/L2≤0.8.

In an embodiment of the present invention, the first height of the micro light-emitting element is smaller than the second height, and (H2-H1)/H1≤0.2.

In an embodiment of the present invention, the first height of the micro light-emitting element is greater than the second height, and (H1-H2)/H1≤0.2.

In an embodiment of the present invention, the thickness of the element layer of the micro light-emitting element is H3, and 0.01≤H1/H3≤0.95.

In an embodiment of the present invention, the element layer of the micro light-emitting element has opposite side edges, and the distance between the two side edges is S2, the shortest distance between the protruding structure and any of the two side edges is S3, and 0.01≤S3/S2≤0.2.

In an embodiment of the present invention, the ratio of the orthographic projection area of the convex structure of the micro light-emitting element on the surface of the element layer to the surface area of the surface of the element layer is less than or equal to 0.8.

In an embodiment of the present invention, the body of the above-mentioned micro light-emitting element includes a first-type semiconductor layer, a light-emitting layer, and a second-type semiconductor layer. The light emitting layer is disposed on the first type semiconductor layer. The second type semiconductor layer is disposed on the light emitting layer. The bump structure is connected to the second type semiconductor layer.

In an embodiment of the present invention, the element layer of the micro light-emitting element includes a first-type semiconductor layer, a light-emitting layer, and a second-type semiconductor layer. The light emitting layer is disposed on the first type semiconductor layer. The second type semiconductor layer is disposed on the light emitting layer. The raised structure includes at least part of the second type semiconductor layer.

In an embodiment of the present invention, the above-mentioned protruding structure of the micro light-emitting element includes a second-type semiconductor layer, a light-emitting layer and a part of the first-type semiconductor layer.

In an embodiment of the present invention, the above-mentioned micro light-emitting element further includes an insulating layer and a conductive layer. The insulating layer partially covers the first type semiconductor layer and the protruding structure. The conductive layer is disposed on the insulating layer and is connected to the second-type semiconductor layer in the raised structure exposed outside the insulating layer. The second electrode is connected to the conductive layer, and the first electrode is connected to the first type semiconductor layer.

In an embodiment of the present invention, the first electrode and the second electrode of the above-mentioned micro light-emitting element have different electrical properties.

In an embodiment of the present invention, the orthographic projections of the first bonding pads and the second bonding pads of the above-mentioned display device on the backplane are respectively partially overlapped with the orthographic projections of the protruding structures on the backplane.

In an embodiment of the present invention, the orthographic projections of the first bonding pads, the second bonding pads and the protruding structures of the above-mentioned display device on the backplane are staggered from each other.

In an embodiment of the present invention, the top surface of the above-mentioned protruding structure of the display device is flush with the surface of the back plate.

In an embodiment of the present invention, the back plate of the above-mentioned display device has a groove, which is disposed between the corresponding first bonding pads and the second bonding pads. Part of the protruding structure of the micro light-emitting element is arranged in the groove of the backplane.

Based on the above, the micro-light-emitting element and the display device according to an embodiment of the present invention have the protruding structure disposed between the first electrode and the second electrode, which can effectively prevent the micro-light-emitting element from being transferred to the display device during the bonding manufacturing process. The bonding pad connected to the first electrode and the bonding pad connected to the second electrode are connected to each other due to overflow, thereby improving the production yield of the display device and increasing the design margin of the micro light-emitting element.

In order to make the above-mentioned features and advantages of the present invention more obvious and easy to understand, the following embodiments are given and described in detail with the accompanying drawings as follows.

Description of drawings

FIG. 1 is a schematic cross-sectional view of a micro light-emitting device according to an embodiment of the present invention.

FIG. 2 is a schematic top view of a micro light-emitting device according to an embodiment of the present invention.

3 is a schematic cross-sectional view of a micro light-emitting device according to another embodiment of the present invention.

FIG. 4 is a schematic cross-sectional view of a micro light-emitting device according to another embodiment of the present invention.

5A to 5B are schematic cross-sectional views of a bonding process of a display device according to an embodiment of the present invention.

6 is a schematic cross-sectional view of a display device according to another embodiment of the present invention.

7 is a schematic cross-sectional view of a display device according to still another embodiment of the present invention.

【Symbol Description】

10A, 10B, 10C: Display device

11, 11C: Backplane

11Ca: groove

11s, 11Cs, 142s: Surface

12: First bond pad

13: Second bond pad

100, 100A, 100B, 100C, 100D: Micro light-emitting elements

110, 110A, 110B: element layer

110a, 110b: side edges

111, 111A, 111B: first-type semiconductor layers

112, 112A, 112B: light-emitting layer

113, 113A, 113B: second type semiconductor layer

120, 120A, 120B: first electrodes

130, 130A, 130B: the second electrode

140, 140A, 140B, 140C, 140D: Raised structures

140Ct: top surface

142, 142A, 142B: Body

150, 150B, 160: insulating layer

170: Conductive layer

D1: first direction

D2: second direction

D3: third direction

H1: first height

H2: second height

H3: Thickness

L1, L2: length

S1, S2, S3: Spacing

W1, W2, W3, W4: Width

A-A': Section line

Detailed ways

FIG. 1 is a schematic cross-sectional view of a micro light-emitting device according to an embodiment of the present invention. FIG. 2 is a schematic top view of a micro light-emitting device according to an embodiment of the present invention. Figure 1 may correspond to section line A-A' of Figure 2 . In particular, FIG. 2 omits the illustration of the insulating layer 150 in FIG. 1 .

Referring to FIG. 1 and FIG. 2 , in this embodiment, the micro light-emitting element 100 includes an element layer 110 , a first electrode 120 and a second electrode 130 . The first electrode 120 is electrically connected to the element layer 110 . The second electrode 130 is electrically connected to the element layer 110 . The element layer 110 of the micro light-emitting element 100 includes a protruding structure 140 and a body 142 , wherein the protruding structure 140 is disposed between the first electrode 120 and the second electrode 130 and disposed on the body 142 . The first electrode 120 , the second electrode 130 and the protruding structure 140 are disposed on the same side of the element layer 110 . More specifically, the first electrode 120 , the second electrode 130 and the protruding structure 140 are disposed on the same side of the body 142 , and the orthographic projections on the surface 142s of the body 142 do not overlap. In particular, in this embodiment, the connection between the first electrode 120 and the second electrode 130 passes through the protruding structure 140 , and the connection is between any point on the first electrode 120 and any point on the second electrode 130 By definition, further, the orthographic projection of the connection line on the surface 142s will pass through the convex structure 140 , or in other words, the orthographic projection of the connection line on the surface 142s will pass through the convex structure 140 on the surface 142s orthographic projection on .

In this embodiment, the materials of the protruding structure 140 , the first electrode 120 and the second electrode 130 may be the same, for example, selected from gold (Au), tin (Sn), nickel (Ni), titanium (Ti), and indium (In), alloys of the above-mentioned materials, and combinations of the above-mentioned materials, but the present invention is not limited thereto. That is to say, the protruding structure 140, the first electrode 120 and the second electrode 130 can be formed in the same film layer, so as to avoid increasing the extra production cost. In other embodiments, the material of the protruding structure 140 can also be selected from light-transmitting materials, such as silicon oxide, silicon nitride, silicon oxynitride, other suitable inorganic materials, or a stacked layer of at least two of the above materials, so as to Avoid blocking the forward light of the micro light-emitting element 100 .

In this embodiment, the body 142 includes a first-type semiconductor layer 111 , a light-emitting layer 112 and a second-type semiconductor layer 113 , wherein the light-emitting layer 112 is disposed on the first-type semiconductor layer 111 , and the second-type semiconductor layer 113 is disposed on the light-emitting layer 113 . layer 112, but the present invention is not limited thereto. For example, in this embodiment, the protruding structure 140 is connected to the second-type semiconductor layer 113 , but the invention is not limited thereto.

The first type semiconductor layer 111 and the second type semiconductor layer 113 may include II-VI group materials (eg, zinc selenide (ZnSe)) or III-V nitride materials (eg, gallium nitride (GaN), nitride Aluminum (AlN), Indium Nitride (InN), Indium Gallium Nitride (InGaN), Aluminum Gallium Nitride (AlGaN) or Aluminum Indium Gallium Nitride (AlInGaN)). In this embodiment, the first-type semiconductor layer 111 is, for example, an N-type doped semiconductor layer, and the material of the N-type doped semiconductor layer is, for example, N-type gallium nitride (n-GaN). The second-type semiconductor layer 113 is, for example, a P-type doped semiconductor layer, and the material of the P-type doped semiconductor layer is, for example, p-type gallium nitride (p-GaN), but the invention is not limited thereto. In this embodiment, the structure of the light emitting layer 112 is, for example, a multi-layer quantum well structure (MQW), and the multi-layer quantum well structure includes alternately stacked multi-layer indium gallium nitride (InGaN) and multi-layer gallium nitride ( GaN), by designing the ratio of indium or gallium in the light-emitting layer 112, the light-emitting wavelength range of the light-emitting layer 112 can be adjusted, but the present invention is not limited to this.

In this embodiment, the first electrode 120 penetrates through the second type semiconductor layer 113 and the light emitting layer 112 to be connected to the first type semiconductor layer 111 , and the second electrode 130 is connected to the second type semiconductor layer 113 . However, the present invention is not limited thereto. According to other embodiments, the first electrode 120 and the second electrode 130 may be electrically connected to the first type semiconductor layer 111 and the second type semiconductor layer 113 through other conductive layers, respectively. Here, the first electrode 120 is, for example, an N-type electrode, and the second electrode 130 is, for example, a P-type electrode. More specifically, the first electrode 120 and the second electrode 130 have different electrical properties. In this embodiment, the materials of the first electrode 120 and the second electrode 130 are, for example, selected from gold (Au), tin (Sn), nickel (Ni), titanium (Ti), indium (In), and alloys of the above-mentioned materials. and the above combinations, but the present invention is not limited thereto.

Referring to FIG. 1 , in this embodiment, the micro light-emitting element 100 further includes an insulating layer 150 covering the protruding structure 140 , the light-emitting layer 112 , part of the first-type semiconductor layer 111 and part of the second-type semiconductor layer 113 . The first electrode 120 penetrates through the insulating layer 150 , the second type semiconductor layer 113 and the light emitting layer 112 and is connected to the first type semiconductor layer 111 , and the second electrode 130 penetrates through the insulating layer 150 and is connected to the second type semiconductor layer 113 . It is particularly mentioned that a part of the insulating layer 150 covering the protruding structure 140 can also be regarded as a part of the protruding structure 140 , but in an embodiment not shown, the insulating layer 150 can also be omitted. In this embodiment, the material of the insulating layer 150 is, for example, silicon oxide, silicon nitride, silicon oxynitride, other suitable inorganic materials, or a stacked layer of at least two of the above materials, but the invention is not limited thereto.

In this embodiment, the vertical height of the protruding structure 140 on the surface 142s of the body 142 in the first direction D1 on the surface 100s is the first height H1. The vertical height of any one of the first electrode 120 and the second electrode 130 on the surface 142s in the first direction D1 is the second height H2. For example, the first height H1 of the protruding structure 140 and the second height H2 of the first electrode 120 or the second electrode 130 may satisfy the following relationship: 0.8≤H1/H2≤1.2, wherein less than 0.8 will block the bonding process The effect of overflow is not good, and greater than 1.2 will deteriorate the yield of the bonding process. A preferable implementation condition is |H1-H2|≤1 micrometer, which can effectively avoid overflow in the over-bonding process and increase the yield of the bonding process, but the present invention is not limited to this. Specifically, the surface 142s of the body 142 refers to the topmost surface of the body 142 . In some embodiments, the first height H1 of the protruding structure 140 is smaller than the second height H2 of any one of the first electrode 120 and the second electrode 130, and satisfies the following relationship: (H2-H1)/H1≤0.2 , greater than 0.2 will make the effect of blocking the overflow of the bonding process not good. In other embodiments, the first height H1 of the protruding structure 140 is greater than the second height H2 of any one of the first electrode 120 and the second electrode 130, and satisfies the following relationship: (H1-H2)/H1≤ 0.2, greater than 0.2 affects the yield of the bonding process.

In this embodiment, the element layer 110 has a thickness H3 in the first direction D1. For example, the first height H1 of the protruding structure 140 and the thickness H3 of the device layer 110 may satisfy the following relationship: 0.01≤H1/H3≤0.95, wherein less than 0.01 will make the effect of blocking overflow in the bonding process poor, and greater than 0.01 0.95 affects the yield of the bonding process. The preferred implementation condition is 0.3≤H1/H3≤0.7, which can effectively prevent the overflow of the bonding process and increase the yield of the bonding process, but the present invention is not limited to this. Referring to FIG. 2 , in this embodiment, the connection line between the first electrode 120 and the second electrode 130 may be substantially parallel to the second direction D2 (ie, the extending direction of the section line AA'), and the second The direction D2 is substantially perpendicular to the first direction D1, but the present invention is not limited to this. In this embodiment, the protruding structure 140 has a maximum length L1 along the second direction D2, and the first electrode 120 and the second electrode 130 have a distance S1 along the second direction D2. For example, the length L1 of the protruding structure 140 and the distance S1 between the first electrode 120 and the second electrode 130 may satisfy the following relationship: 0.8≤L1/S1≤1, and less than 0.8 will make the overflow blocking effect less effective. good, but the present invention is not limited to this.

In this embodiment, the element layer 110 has a maximum length L2 in the second direction D2. For example, in the present embodiment, the length L1 of the protruding structure 140 and the length L2 of the device layer 110 may satisfy the following relation: L1/L2≤0.8, which prevents the protruding structure 140 from being too close to the edge of the body 142 and causing poor rate decreases, but the present invention is not limited to this. In this embodiment, the protruding structures 140 have the maximum width W1 in the third direction D3 perpendicular to the second direction D2, and the element layer 110 has the maximum width W2 in the third direction D3. For example, in the present embodiment, the width W1 of the protruding structure 140 and the width W2 of the device layer 110 may satisfy the following relationship: W1/W2≤0.8, so as to avoid the protruding structure 140 being too close to the edge of the body 142 and causing poor rate decreases, but the present invention is not limited to this. It is particularly noted that the first electrode 120 and the second electrode 130 respectively have a maximum width W3 and a maximum width W4 in the third direction D3 perpendicular to the second direction D2, wherein the width W1 is larger than the width W3 and the width W4, respectively, and may have Better overflow tolerance.

In this embodiment, the element layer 110 has opposite side edges 110a, 110b, and the distance between the two side edges 110a, 110b is S2. The shortest distance between the protruding structure 140 and any one of the two side edges 110a and 110b is S3. For example, in this embodiment, the distance S2 between the two side edges 110a and 110b of the element layer 110 and the shortest distance S3 between the protruding structure 140 and any of the two side edges 110a and 110b may satisfy the following relational expression: 0.01 ≤S3/S2≤0.2, to prevent the protruding structure 140 from being too close to the two side edges 110a of the device layer 110 to cause problems such as sidewall leakage, and thus to reduce the yield, but the invention is not limited to this. In particular, in some preferred embodiments, the shortest distance S3 between the protruding structure 140 and any one of the two side edges 110a and 110b may be less than or equal to 10 micrometers.

In this embodiment, the ratio of the orthographic projection area of the protruding structures 140 on the surface 142s of the body 142 to the surface area of the surface 142s of the body 142 may be less than or equal to 0.8, and greater than 0.8 will cause the proportion of the protruding structures 140 to be too large. The tolerance of overflow is reduced, but the present invention is not limited to this. Although some embodiments of the present invention are specific to the description of miniature light-emitting elements including p-n diodes, it should be understood that embodiments of the present invention are not limited thereto, and certain embodiments may also be applied to other miniature semiconductor elements, including controllable execution of predetermined electronic functions micro-semiconductor components (eg diodes, transistors, integrated circuits) or micro-semiconductor components with photonic functions (eg light-emitting diodes, laser diodes, photodiodes). Other embodiments of the invention may also be applied to microchips comprising circuits, such as Si or SOI wafers for logic or memory applications, or GaAs wafers for RF communication applications.

3 is a schematic cross-sectional view of a micro light-emitting device according to another embodiment of the present invention. Referring to FIG. 3 , the main difference between the micro light emitting element 100A in this embodiment and the micro light emitting element 100 shown in FIG. 1 is that the protruding structure 140A of the micro light emitting element 100A includes at least part of the second type semiconductor layer 113A.

In this embodiment, the first electrode 120A penetrates through the second type semiconductor layer 113A and the light emitting layer 112A of the body 142A and is electrically connected to the first type semiconductor layer 111A exposed outside the insulating layer 150 , and the second electrode 130A is connected to the insulating layer 111A exposed to the outside. The second type semiconductor layer 113A outside the layer 150, but the invention is not limited to this. In this embodiment, the first height H1 of the protruding structure 140A and the thickness H3 of the element layer 110A satisfy the following relationship: 0.01≤H1/H3≤0.3, so as to effectively prevent the overflow of the bonding process and increase the yield of the bonding process .

FIG. 4 is a schematic cross-sectional view of a micro light-emitting device according to another embodiment of the present invention. Referring to FIG. 4 , the main difference between the micro light emitting element 100B in this embodiment and the micro light emitting element 100 shown in FIG. 1 is that the protruding structure 140B of the micro light emitting element 100B includes the second type semiconductor layer 113B and the light emitting layer 112B. For example, in this embodiment, the protruding structure 140B further includes a part of the first type semiconductor layer 111B, and the body 142B includes a part of the first type semiconductor layer 111B, but the invention is not limited thereto. In the present embodiment, the light emitting layer 112B is located in the protruding structure 140B in the center, and the first electrode 120B and the second electrode 130B are disposed on both sides of the protruding structure 140B. Therefore, the current density of the micro light emitting element 100B is concentrated, so as to increase the light extraction efficiency of the micro light emitting element 100B, and avoid problems such as side leakage.

In particular, the protruding structure 140B and the body 142B in this embodiment can be formed by the same manufacturing method, for example, both are formed by metal-organic chemical vapor deposition (Metal-organic Chemical Vapor Deposition). More preferably, the first-type semiconductor layer 111B, the light-emitting layer 112B and the second-type semiconductor layer 113B are completed first, and then the protruding structure 140B and the body 142B are respectively formed by yellow light, etching, etc., so as to increase the micro light-emitting element 100B. the production efficiency, but the present invention is not limited to this. In this embodiment, the first height H1 of the protruding structure 140B and the thickness H3 of the element layer 110B satisfy the following relationship: 0.7≤H1/H3≤0.95, wherein less than 0.7 will make the effect of blocking the overflow in the bonding process poor, Greater than 0.95 affects the yield of the bonding process.

In this embodiment, the first electrode 120B and the second electrode 130B are disposed on the first type semiconductor layer 111B. The micro light-emitting element 100B further includes an insulating layer 160 and a conductive layer 170 . The insulating layer 160 partially covers the first-type semiconductor layer 111B and the protruding structure 140B. The conductive layer 170 is disposed on the insulating layer 160 and is connected to the second-type semiconductor layer 113B exposed outside the insulating layer 160 in the bump structure 140B. For example, the second electrode 130B is electrically connected to the second type semiconductor layer 113B through the conductive layer 170 , and the first electrode 120B is connected to the first type semiconductor layer 111B exposed outside the insulating layer 150B, but the invention is not limited thereto . In this embodiment, the insulating layer 160 and the insulating layer 150B can be made of the same material, such as silicon oxide, silicon nitride, silicon oxynitride, other suitable inorganic materials, or a stacked layer of at least two of the above materials. Inventions are not limited to this. It is particularly mentioned that the part of the insulating layer 150B, the insulating layer 160 and the conductive layer 170 covering the raised structure 140B can also be regarded as a part of the raised structure 140B.

In this embodiment, based on the consideration of conductivity, the material of the conductive layer 170 is generally a metal material. However, the present invention is not limited thereto, and in some embodiments, the material of the conductive layer 170 may also use other conductive materials, such as alloys, nitrides of metal materials, oxides of metal materials, oxynitrides of metal materials, or Other suitable materials, or stacked layers of metallic materials and other conductive materials. In other embodiments, the material of the conductive layer 170 may also be a conductive material with high reflectivity, such as silver (Ag), aluminum (Al) or gold (Au), to improve the effective light extraction intensity of the micro light-emitting element 100B.

5A to 5B are schematic cross-sectional views of a bonding process of the display device 10A according to an embodiment of the present invention. FIG. 5A shows a schematic cross-sectional view of transferring a plurality of micro light-emitting elements 100 to the backplane 11 . Referring to FIG. 5A , in this embodiment, the display device 10A includes a plurality of micro light-emitting elements 100 , a backplane 11 , a plurality of first bonding pads 12 and a plurality of second bonding pads 13 . The plurality of first bonding pads 12 are respectively disposed on the backplane 11 corresponding to the first electrodes 120 of the plurality of micro light emitting elements 100 , and the plurality of second bonding pads 13 are respectively disposed corresponding to the second electrodes 130 of the plurality of micro light emitting elements 100 . Backplane 11. In this embodiment, the materials of the first bonding pads 12 and the second bonding pads 13 are selected from, for example, gold, copper, tin, indium, alloys of the above-mentioned materials and compositions of the above-mentioned materials, or solder paste. , but the present invention is not limited to this. According to other embodiments, the materials of the first bonding pad 12 and the second bonding pad 13 may also be anisotropic conductive film (ACF) or other suitable bonding materials.

5B shows a schematic cross-sectional view of the display device 10A of the present embodiment after the plurality of first bonding pads 12 and the plurality of second bonding pads 13 are heated and cured. Referring to FIG. 5B , after the plurality of first bonding pads 12 and the plurality of second bonding pads 13 in FIG. 5A are heated to a molten state, the plurality of first bonding pads 12 and the plurality of second bonding pads 13 in the molten state are displayed overflow along the surface 11s of the back plate 11, respectively. The first bonding pads 12 and the second bonding pads 13 flowing toward the raised structures 140 overflow into between the raised structures 140 and the back plate 11 . In particular, in this embodiment, the first bonding pads 12 and the second bonding pads 13 overflowing between the protruding structures 140 and the back plate 11 do not contact each other. That is to say, the protruding structure 140 in this embodiment can greatly reduce the probability of short circuit caused by overflow when the first bonding pad 12 and the second bonding pad 13 are in a molten state.

After the first bonding pad 12 and the second bonding pad 13 are cooled and solidified, the first electrode 120 of the micro light emitting element 100 is electrically connected to the backplane 11 through the first bonding pad 12, and the second electrode 130 of the micro light emitting element 100 is electrically connected to the backplane 11 through the first bonding pad 12. The two bonding pads 13 are electrically connected to the backplane 11 to form the display device 10A of this embodiment. In this embodiment, the orthographic projections of the first bonding pads 12 and the second bonding pads 13 on the backplane 11 respectively partially overlap the orthographic projections of the protruding structures 140 on the backplane 11 , but the invention is not limited to this. . In some embodiments, the orthographic projections of the first bonding pads 12 , the second bonding pads 13 and the protruding structures 140 on the backplane 11 are offset from each other.

Specifically, in this embodiment, the display device 10A is, for example, a Micro LEDs Display. Depending on its application, the miniature light emitting diode display may contain other components. These other components include (but are not limited to): memory, modality controller and battery. In other embodiments, the miniature light emitting diode display may be a television, tablet, telephone, laptop, computer monitor, stand-alone terminal kiosk, digital camera, handheld game console, media display, e-book display , vehicle displays or large-area electronic signage displays. In addition, compared with the general light-emitting diode technology, the micro light-emitting element is reduced from millimeters to micrometers, so the micro-LED display can reach high resolution, and can reduce the power consumption of the display, and also has the advantages of energy saving, simple structure, thin, etc. Advantage.

In this embodiment, the backplane 11 is, for example, a pixel array substrate, and the pixel array substrate can be selected from a complementary metal oxide semiconductor CMOS (Complementary Metal Oxide Semiconductor) substrate, a liquid crystal on silicon (LCOS) substrate, a thin film transistor TFT (Thin Film Transistor) substrate or other substrates with driving circuits. The plurality of micro light emitting elements 100 may include micro light emitting diodes with different emission wavelength ranges (eg, red light, blue light, green light), but the invention is not limited thereto.

In this embodiment, the orthographic profile of the protruding structure 140 of the micro light-emitting element 100 on the surface 11s of the backplane 11 is a rectangle. However, the present invention is not limited to this. According to other embodiments, the orthographic profile of the protruding structures 140 of the micro light-emitting element 100 on the surface 11s of the back plate 11 may also be a square, a circle, a diamond or other suitable shapes. shape. It is worth mentioning that, in some embodiments, the orthographic profile of the protruding structures 140 of the plurality of micro light emitting elements 100 applied to the display device (eg, a micro light emitting diode display) on the surface 11s of the backplane 11 can be determined according to Different shapes are used for different emission wavelength ranges. In this way, during the process of transferring a plurality of micro light-emitting elements to the backplane (eg, a pixel array substrate), the protruding structures 140 with different appearances can improve the alignment accuracy of different color pixels.

6 is a schematic cross-sectional view of a display device according to another embodiment of the present invention. Referring to FIG. 6 , the difference between the display device 10B of this embodiment and the display device 10A of FIG. 5B is that the top surface 140Ct of the protruding structure 140C of the micro light-emitting element 100C is flush with the surface 11s of the backplane 11 . Therefore, during the bonding process, the first bonding pads 12 and the second bonding pads 13 in the molten state can be completely blocked by the protruding structures 140C of the micro light-emitting device 100C, which can greatly reduce the first bonding pads 12 and the second bonding pads. 13 Probability of short circuit due to overflow when in molten state. It is particularly noted that the protruding structure 140C includes the insulating layer 150, but the insulating layer 150 can also be omitted, as long as the first bonding pad 12 and the second bonding pad 13 in the molten state are blocked, it belongs to the present invention scope.

FIG. 7 is a schematic cross-sectional view of a display device 10C according to still another embodiment of the present invention. Referring to FIG. 7 , the difference between the display device 10C of this embodiment and the display device 10B of FIG. 6 is that the back plate 11C has a plurality of grooves 11Ca, and each groove 11Ca is respectively disposed in a corresponding position of a micro light-emitting element 100D. between a set of first bonding pads 12 and second bonding pads 13 . In this embodiment, part of the protruding structures 140D of the micro light-emitting element 100D is disposed in the groove 11Ca of the back plate 11C. Therefore, compared with the display device 10B of FIG. 6 , the display device 10C of the present embodiment can further reduce the probability of short circuit caused by overflow when the first bonding pad 12 and the second bonding pad 13 are in a molten state.

It is particularly mentioned that the orthographic profile of the groove 11Ca of the back plate 11C on the surface 11Cs of the back plate 11C in this embodiment is, for example, a rectangle, but the present invention is not limited to this. In some embodiments, the back plate 11C The orthographic profile of the groove 11Ca on the surface 11Cs of the back plate 11C can also be square, circular, diamond or other suitable shapes to match the orthographic profile of the micro light emitting element 100D on the surface 11Cs of the back plate 11C. That is to say, a plurality of micro-shaped light-emitting elements 100D (eg, micro-LEDs with different light-emitting colors) applied to a display device (eg, a micro-LED display) can be formed on the surface 11Cs by the grooves 11Ca on the backplane 11C. The projection outline is aligned to improve the alignment accuracy of different color rendering pixels.

To sum up, the micro-light-emitting element and the display device according to the embodiments of the present invention have the protruding structure disposed between the first electrode and the second electrode, so that the micro-light-emitting element can be transferred to the display device in the bonding manufacturing process. It can effectively prevent the bonding pads connected to the first electrode and the bonding pads connected to the second electrode from being connected to each other due to overflow, thereby improving the production yield of the display device and increasing the design margin of the micro light-emitting element.

Although the present invention has been disclosed above with examples, it is not intended to limit the present invention. Any person skilled in the art can make some changes and modifications without departing from the spirit and scope of the present invention. The protection scope of the invention shall be determined by the claims.

Claims (18)

1. A miniature light-emitting element, characterized in that, comprising: an element layer, comprising a body and a protruding structure disposed on the body, the body having a surface; a first electrode, electrically connected to the element layer; and A second electrode, electrically connected to the element layer, wherein the first electrode, the protruding structure and the second electrode are disposed on the same side of the body, wherein the protruding structure is located on the first between the electrode and the second electrode, and the connection line between the first electrode and the second electrode passes through the protruding structure, Wherein the protruding structure has a first height on the surface, any one of the first electrode and the second electrode has a second height on the surface, the first height is H1, the second The height is H2, and 0.8≤H1/H2≤1.2. 2 . The micro light-emitting element according to claim 1 , wherein the maximum length of the protruding structure is L1 , the distance between the first electrode and the second electrode is S1 , and 0.8≦L1/S1≦1. 3 . 3. The micro light-emitting element according to claim 2, wherein the maximum length of the element layer is L2, and L1/L2≤0.8. 4. The micro light-emitting element according to claim 1, wherein the first height is smaller than the second height, and (H2-H1)/H1≤0.2. 5. The micro light-emitting element according to claim 1, wherein the first height is greater than the second height, and (H1-H2)/H1≤0.2. 6. The micro light-emitting element according to claim 1, wherein the thickness of the element layer is H3, and 0.01≤H1/H3≤0.95. 7 . The micro light-emitting element according to claim 1 , wherein the element layer has opposite side edges, and the distance between the two side edges is S2 , the protruding structure and any one of the two side edges The shortest spacing is S3, and 0.01≤S3/S2≤0.2. 8 . The micro light-emitting element according to claim 1 , wherein the ratio of the orthographic projection area of the protruding structure on the surface of the body to the surface area of the surface of the body is less than or equal to 0.8. 9 . 9. The micro light emitting element of claim 1, wherein the body comprises: first type semiconductor layer; a light-emitting layer disposed on the first-type semiconductor layer; and A second-type semiconductor layer is disposed on the light-emitting layer, wherein the protruding structure is connected to the second-type semiconductor layer. 10. The micro light-emitting element of claim 1, wherein the element layer comprises: first type semiconductor layer; a light-emitting layer disposed on the first-type semiconductor layer; and A second-type semiconductor layer is disposed on the light-emitting layer, wherein the protruding structure includes at least part of the second-type semiconductor layer. 11. The micro light-emitting element according to claim 10, wherein the protruding structure comprises the second-type semiconductor layer, the light-emitting layer and a part of the first-type semiconductor layer. 12. The micro light-emitting element of claim 11, further comprising: an insulating layer partially covering the first-type semiconductor layer and the protruding structure; and a conductive layer disposed on the insulating layer and connected to the second-type semiconductor layer in the raised structure exposed outside the insulating layer, The second electrode is connected to the conductive layer, and the first electrode is connected to the first-type semiconductor layer. 13. The micro light-emitting element according to claim 1, wherein the first electrode and the second electrode have different electrical properties. 14. A display device, comprising: Multiple miniature light-emitting elements, including: an element layer, comprising a body and a protruding structure disposed on the body, the body having a surface; a first electrode, electrically connected to the element layer; and a second electrode, electrically connected to the element layer; The first electrode, the protruding structure and the second electrode are disposed on the same side of the body, wherein the protruding structure is located between the first electrode and the second electrode, and the The connection line between the first electrode and the second electrode passes through the protruding structure, and the protruding structure is perpendicular to the surface and has a first height. one is perpendicular to the surface and has a second height, the first height is H1, the second height is H2, and 0.8≤H1/H2≤1.2; backplane; and The first bonding pad and the second bonding pad are arranged on the backplane, The first electrode of the micro light emitting element is electrically connected to the backplane through the first bonding pad, and the second electrode of the micro light emitting element is electrically connected to the backplane through the second bonding pad the backplane, and the first bond pad and the second bond pad are separated from each other. 15 . The display device according to claim 14 , wherein the orthographic projections of the first bonding pad and the second bonding pad on the backplane respectively partially overlap the raised structures on the backplane. 16 . orthographic projection. 16 . The display device of claim 14 , wherein orthographic projections of the first bonding pad, the second bonding pad, and the protruding structure on the backplane are staggered from each other. 17 . 17. The display device of claim 16, wherein a top surface of the raised structure is flush with a surface of the back plate. 18. The display device of claim 14, wherein the back plate has a groove disposed between the corresponding first bonding pad and the second bonding pad, and a portion of the micro light emitting element The protruding structure is arranged in the groove of the back plate.

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