CN113937197A

CN113937197A - Micro light-emitting diode display panel

Info

Publication number: CN113937197A
Application number: CN202111193791.0A
Authority: CN
Inventors: 杨翔甯; 朱永祺; 罗玉云; 吴柏威; 彭钰雅
Original assignee: PlayNitride Inc
Current assignee: PlayNitride Inc
Priority date: 2021-10-13
Filing date: 2021-10-13
Publication date: 2022-01-14

Abstract

The present disclosure provides a micro light emitting diode display panel. The micro light emitting diode display panel comprises a driving substrate and a plurality of bonding pads, wherein the bonding pads are arranged on the driving substrate at intervals. The micro light-emitting diode display panel also comprises a plurality of micro light-emitting diode structures, and the micro light-emitting diode structures are electrically connected with the bonding pads. Each micro light-emitting diode structure comprises at least one electrode, and the electrode is arranged on one side, facing the driving substrate, of the micro light-emitting diode structure. The electrode has a front contact surface facing the driving substrate and side contact surfaces laterally connected to the corresponding bonding pads.

Description

Micro light-emitting diode display panel

Technical Field

The present disclosure relates to a light emitting diode display panel, and more particularly, to a micro light emitting diode display panel, in which a micro light emitting diode structure of the micro light emitting diode display panel is laterally connected to a bonding pad on a driving substrate through a side contact surface of an electrode.

Background

With the progress of the optoelectronic technology, the volume of the optoelectronic device is gradually reduced. Compared with an organic light-emitting diode (OLED), a micro LED (mLED/μ LED) has the advantages of high efficiency, long service life, and relatively stable material due to environmental influence. Therefore, the market has been increasingly receiving attention for displays using micro light emitting diodes fabricated in an array arrangement.

In a typical micro led display panel, electrodes of the micro leds are front-bonded (i.e., forward-bonded) to bumps (bumps) on a substrate to electrically connect the micro leds to the substrate. With the miniaturization of micro leds, the area of the electrode in each micro led structure is also reduced, and when the electrode of the micro led is bonded to the bump on the substrate, horizontal shift (horizontal shift) may occur, which may easily cause an open circuit or a short circuit.

In addition, when repairing or removing a failed (fail) micro led, the micro led is often removed from the back side of the substrate by laser trimming (laser trimming). However, since the bump is made of metal and is liable to reflect laser, the front bonding method causes the laser energy to be blocked by the bump on the substrate and thus is difficult to act on the interface between the electrode and the bump. Under the limitation, the conventional laser trimming process can only directly burn and melt the bumps on the substrate and re-manufacture the bumps in situ, and cannot be reused. That is, the conventional front bonding method is difficult to perform non-destructive removal by peeling (bonding).

Another way of trimming is to reserve additional space on the substrate to dispose additional bumps, and after the failed micro-leds are removed by laser trimming, the repaired micro-leds are bonded with the additional bumps. However, this method occupies the pixel space of the micro led display panel, which is not favorable for increasing the pixel density of the display.

Disclosure of Invention

The micro light emitting diode display panel of the embodiment of the disclosure comprises a plurality of micro light emitting diode structures. Since each micro light emitting diode structure is laterally connected to the bonding pad on the driving substrate through the side contact surface of the electrode, when the contact surface of the electrode and the bonding pad is irradiated with laser light (e.g., from the back surface of the driving substrate) to peel off the failed micro light emitting diode, the bonding pad is locally melted only at the contact surface. Therefore, the bonding pads can be reused without reserving other space for arranging additional bonding pads or manufacturing the bonding pads again. In addition, the space of the removed micro-led structure can directly accommodate (bond) the new micro-led structure.

The disclosed embodiments include a micro light emitting diode display panel. The micro light emitting diode display panel comprises a driving substrate and a plurality of bonding pads, wherein the bonding pads are arranged on the driving substrate at intervals. The micro light-emitting diode display panel also comprises a plurality of micro light-emitting diode structures, and the micro light-emitting diode structures are electrically connected with the bonding pads. Each micro light-emitting diode structure comprises at least one electrode, and the electrode is arranged on one side, facing the driving substrate, of the micro light-emitting diode structure. The electrode has a front contact surface facing the driving substrate and a side contact surface laterally connected to the bonding pad.

Drawings

The embodiments of the present disclosure will be described in detail below with reference to the accompanying drawings. It should be noted that the various features are not drawn to scale and are merely illustrative examples. In fact, the dimensions of the components may be exaggerated or minimized to clearly illustrate the technical features of the embodiments of the present disclosure.

Fig. 1A-1B are partial cross-sectional views illustrating various stages in transferring a micro light emitting diode structure onto a driving substrate to form a micro light emitting diode display panel according to an embodiment of the disclosure;

FIG. 2 is a partial cross-sectional view illustrating a micro light emitting diode display panel according to one embodiment of the present disclosure;

FIG. 3 is a partial cross-sectional view illustrating a micro light emitting diode display panel according to another embodiment of the present disclosure;

FIG. 4 is a partial cross-sectional view illustrating a micro light emitting diode display panel according to another embodiment of the present disclosure;

FIG. 5 is a partial cross-sectional view illustrating a micro light emitting diode display panel according to another embodiment of the present disclosure;

FIG. 6 is a partial cross-sectional view illustrating a micro light emitting diode display panel according to another embodiment of the present disclosure;

FIG. 7 is a partial cross-sectional view illustrating a micro light emitting diode display panel according to one embodiment of the present disclosure;

FIG. 8 is a partial cross-sectional view illustrating a micro light emitting diode display panel according to another embodiment of the present disclosure;

fig. 9 to 13 show different examples of the bonding pad.

Description of the reference numerals

100,102,104,106,108,110,112,114 micro LED display panel

10 base plate

10B back side

12,12-1,12-2 bonding pad

12P projection

Wiring layer 14

14T top surface

16 passivation layer

16B bottom surface

16T top surface

18 isolation structure

20, 20' micro light-emitting diode structure

22 epitaxial layer

24 insulating layer

26,26 ', 28, 28': electrodes

26-1,28-1: body part

26-2,28-2 extension

26N,28N positive contact surface

26S,28S side contact surface

29 flat layer

29O hole

29S surface

LS laser

Angle theta 1, theta 2

Detailed Description

The following disclosure provides many different embodiments, or examples, for implementing different features of the disclosure. The following disclosure describes specific examples of components and arrangements thereof to simplify the description. Of course, these specific examples are not intended to be limiting. For example, if the embodiments of the present disclosure describe that a first feature is formed on or above a second feature, that means that the embodiments may include an embodiment in which the first feature and the second feature are in direct contact, the embodiments may also include an embodiment in which other features are formed between the first feature and the second feature, and the first feature and the second feature may not be in direct contact.

It should be understood that additional operational steps may be performed before, during, or after the method, and that in other embodiments of the method, portions of the operational steps may be replaced or omitted.

Furthermore, spatially relative terms, such as "below …," "below …," "below," "above …," "above …," "above," and the like, may be used herein to facilitate describing the relationship of one element(s) or feature to another element(s) or feature in the drawings and include different orientations of the device in use or operation and the orientation depicted in the drawings. When the device is turned to a different orientation (rotated 90 degrees or otherwise), the spatially relative adjectives used herein will also be interpreted in terms of the turned orientation.

In the specification, the term "about", "about" or "substantially" generally means within 20%, or within 10%, or within 5%, or within 3%, or within 2%, or within 1%, or within 0.5% of a given value or range. The amounts given herein are approximate, that is, the meanings of "about", "about" and "substantially" may be implied without specifically stating "about", "about" or "substantially".

Unless defined otherwise, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs. It will be understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and the present disclosure and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.

Different embodiments disclosed below may repeat use of the same reference symbols and/or designations. These iterations are for simplicity and clarity and are not intended to limit the particular relationship between the various embodiments and/or configurations discussed.

Fig. 1A to 1B are partial cross-sectional views illustrating stages of transferring a micro light emitting diode structure 20 onto a driving substrate 10 to form a micro light emitting diode display panel 100 according to an embodiment of the disclosure. It should be noted that some components of the micro led display panel 100 have been omitted in fig. 1A to 1B in order to more clearly show the technical features of the embodiments of the present disclosure.

Referring to fig. 1A, in some embodiments, a drive substrate 10 is provided. The driving substrate 10 may be, for example, a display substrate, a light emitting substrate, a substrate having a thin-film transistor (TFT) or an Integrated Circuit (IC), or other types of circuit substrates, but the embodiment of the disclosure is not limited thereto. For example, the driving substrate 10 may be a bulk (bulk) semiconductor substrate or include a composite substrate formed of different materials, and the driving substrate 10 may be doped (e.g., using p-type or n-type dopants) or undoped. In addition, the driving substrate 10 may include a semiconductor substrate, a glass substrate or a ceramic substrate, such as a silicon substrate, a silicon germanium substrate, a silicon carbide substrate, an aluminum nitride substrate, a sapphire (sapphire) substrate, a combination thereof or the like, but the embodiment of the disclosure is not limited thereto.

Referring to fig. 1A, in some embodiments, a plurality of bonding pads 12 are formed over a driving substrate 10. As shown in fig. 1A, in some embodiments, a plurality of bonding pads 12 are disposed on the driving substrate 10 at intervals. The bonding pad 12 comprises a conductive material, such as a metal, a metal silicide, a similar material, or a combination thereof, but the embodiment of the disclosure is not limited thereto. For example, the metal may include gold (Au), nickel (Ni), platinum (Pt), palladium (Pd), iridium (Ir), titanium (Ti), chromium (Cr), tungsten (W), aluminum (Al), copper (Cu), similar materials, alloys thereof, or combinations thereof, but the embodiments of the disclosure are not limited thereto.

In addition, the bonding pads 12 may be disposed on the driving substrate 10 by a deposition process and a patterning process at intervals. The deposition process includes, for example, a chemical vapor deposition process, an atomic layer deposition process, a spin-on process, a similar deposition process, or a combination thereof, but the disclosure is not limited thereto. The patterning process may include forming a mask layer (not shown) on the material, and then etching the portion of the material not covered by the mask layer to form the spaced apart bonding pads 12, but the embodiment of the disclosure is not limited thereto.

As shown in fig. 1A, in some embodiments, a plurality of wiring layers 14 are formed on the driving substrate 10, and the wiring layers 14 are electrically connected to the bonding pads 12. Specifically, the wiring layer 14 may be in direct contact with the corresponding bonding pad 12. The wiring layer 14 includes a conductive material, such as a metal, a metal silicide, a similar material, or a combination thereof, but the embodiment of the disclosure is not limited thereto. Examples of metals are as previously described and are not repeated here. The material of the wiring layer 14 may be the same as or different from the material of the bonding pad 12. For example, the wiring layer 14 may include copper (Cu), and the bonding pads 12 may include gold (Ag), but the embodiments of the disclosure are not limited thereto. In addition, the wiring layers 14 may be disposed above the driving substrate 10 by a deposition process and a patterning process, spaced apart from each other. Examples of the deposition process and the patterning process are as described above and will not be repeated here.

As shown in fig. 1A, in some embodiments, a plurality of passivation layers 16 are formed over the wiring layer 14. For example, the passivation layer 16 may include an oxide such as silicon oxide, a nitride such as silicon nitride, similar materials, or a combination thereof, but the embodiments of the present disclosure are not limited thereto. The passivation layer 16 may be formed over the wiring layer 14 by a deposition process. For example, the passivation layer 16 may be disposed on the top surface 14T of the wiring layer 14 as shown in fig. 1A, but the disclosure is not limited thereto.

As shown in fig. 1A, in some embodiments, a plurality of isolation structures 18 are formed on the driving substrate 10, and the isolation structures 18 are disposed on a side of the driving substrate 10 facing the micro light emitting diode structures 20. Specifically, as shown in fig. 1A, the isolation structure 18 may be disposed between two bonding pads 12 in a pair (e.g., the bonding pad 12-1 and the bonding pad 12-2 in fig. 1A), but the embodiment of the disclosure is not limited thereto. The isolation structure 18 may include an inorganic compound (e.g., silicon oxide, silicon nitride) or an organic compound having electrical insulation properties. In addition, the isolation structure 18 may be formed on the driving substrate 10 by a deposition process and a patterning process. Examples of the deposition process and the patterning process are as described above and will not be repeated here.

Referring to fig. 1A, in some embodiments, a micro light emitting diode structure 20 is provided. The micro led structure 20 includes an epitaxial layer 22, where the epitaxial layer 22 includes a first type semiconductor layer, a light emitting layer and a second type semiconductor layer (not shown in fig. 1A and 1B in detail), the light emitting layer is disposed on the first type semiconductor layer, and the second type semiconductor layer is disposed on the light emitting layer. In other words, the light emitting layer is disposed between the first type semiconductor layer and the second type semiconductor layer, but the embodiment of the disclosure is not limited thereto.

The first type semiconductor layer includes an N-type semiconductor material. For example, the first type semiconductor layer may include a ii-vi material, such as zinc selenide (ZnSe), or a iii-v material, such as gallium nitride (GaN), aluminum nitride (AlN), indium nitride (InN), indium gallium nitride (InGaN), aluminum gallium nitride (AlGaN), or aluminum indium gallium nitride (AlInGaN), and the first type semiconductor layer may include a dopant, such as silicon (Si) or germanium (Ge), but the embodiments of the disclosure are not limited thereto. In addition, the first-type semiconductor layer may be a single-layer or multi-layer structure.

The light-emitting layer comprises at least one undoped semiconductorThe layer is at least one low-doped semiconductor layer. For example, the light emitting layer is a Quantum Well (QW) layer, which may include indium gallium nitride (InxGa)_1-xN) or gallium nitride (GaN), but the embodiments of the disclosure are not so limited. Alternatively, the light emitting layer may be a Multiple Quantum Well (MQW) layer, but the embodiment of the disclosure is not limited thereto.

In addition, the light emitting layer may emit red (red) light, green (green) light, or blue (blue) light, but the embodiment of the disclosure is not limited thereto. For example, the light emitting layer may also emit white (white) light, cyan (cell) light, magenta (magenta) light, yellow (yellow) light, other suitable colored light, or a combination thereof.

The second type semiconductor layer comprises a P-type semiconductor material. For example, the second type semiconductor layer may include a ii-vi material such as zinc selenide (ZnSe) or a iii-v material such as gallium nitride (GaN), aluminum nitride (AlN), indium nitride (InN), indium gallium nitride (InGaN), aluminum gallium nitride (AlGaN), or aluminum indium gallium nitride (AlInGaN), and the second type semiconductor layer may include a dopant such as magnesium (Mg), carbon (C), but the disclosure is not limited thereto. In addition, the second type semiconductor layer may have a single layer or a multi-layer structure.

Referring to fig. 1A, in some embodiments, the micro light emitting diode structure 20 also includes an electrode 26 and an electrode 28, and the electrode 26 and the electrode 28 are disposed on a side of the micro light emitting diode structure 20 facing the driving substrate 10 and electrically connected to the epitaxial layer 22. For example, the

electrodes

26 and 28 may be electrically connected to a first semiconductor layer and a second semiconductor layer (not shown in fig. 1A and 1B in detail) of the epitaxial layer 22, respectively, but the disclosure is not limited thereto.

The

electrodes

26 and 28 comprise a conductive material, such as a metal, a metal silicide, a similar material, or a combination thereof, but the embodiments of the disclosure are not limited thereto. For example, the metal may include gold (Au), nickel (Ni), platinum (Pt), palladium (Pd), iridium (Ir), titanium (Ti), chromium (Cr), tungsten (W), aluminum (Al), copper (Cu), similar materials, alloys thereof, or combinations thereof, but the embodiments of the disclosure are not limited thereto. The

electrodes

26 and 28 may be formed by physical vapor deposition, chemical vapor deposition, atomic layer deposition, evaporation, sputtering, the like, or combinations thereof, but the embodiments of the disclosure are not limited thereto.

Referring to fig. 1A, in some embodiments, the micro light emitting diode structure 20 further includes an insulating layer 24, and the insulating layer 24 is disposed on the epitaxial layer 22. For example, the insulating layer 24 may comprise an oxide such as silicon oxide, a nitride such as silicon nitride, similar materials, or a combination thereof, but the embodiments of the present disclosure are not limited thereto. The insulating layer 24 may be formed on a surface of the epitaxial layer 22 facing the driving substrate 10 and a side surface of the epitaxial layer 22 by a deposition process, but the embodiment of the disclosure is not limited thereto. In addition, a patterning process may be performed to remove a portion of the insulating layer 24, such that the

electrodes

26 and 28 are electrically connected to the epitaxial layer 22, but the disclosure is not limited thereto. Examples of the deposition process and the patterning process are as described above and will not be repeated here.

Referring to fig. 1B, the micro light emitting diode structure 20 is bonded to the driving substrate 10 to form the micro light emitting diode display panel 100. For example, the micro led structures 20 may be transferred onto the driving substrate 10 by a (thermal) pressing process (only one micro led structure 20 is shown in fig. 1B), but the disclosure is not limited thereto. As shown in fig. 1A and 1B, in some embodiments, the electrode 26 has a front contact surface 26N and a side contact surface 26S, the front contact surface 26N faces the driving substrate 10, and the side contact surface 26S is laterally connected to the corresponding bonding pad 12 (12-1). Similarly. As shown in fig. 1A and 1B, in some embodiments, the electrode 28 has a front contact surface 28N and a side contact surface 28S, the front contact surface 28N faces the driving substrate 10, and the side contact surface 28S is laterally connected with the corresponding bonding pad 12 (12-2).

As shown in fig. 1B, in the embodiment of the disclosure, the micro led display panel 100 includes a driving substrate 10 and a plurality of bonding pads 12, wherein the bonding pads 12 are disposed on the driving substrate 10 at intervals. The micro led display panel 100 also includes a plurality of micro led structures 20, and the micro led structures 20 are electrically connected to the bonding pads 12. Each micro led structure 20 comprises at least one electrode (26, 28) disposed on a side of the micro led structure 20 facing the driving substrate 10. The electrodes have front contact surfaces (26N, 28N) and side contact surfaces (26S, 28S), the front contact surfaces (26N, 28N) facing the drive substrate 10, and the side contact surfaces (26S, 28S) laterally connected to the corresponding bonding pads 12.

As shown in fig. 1B, in some embodiments, both the positive contact surface 26N of the electrode 26 and the positive contact surface 28N of the electrode 28 are in direct contact with the drive substrate 10. In some other embodiments, the surface of the driving substrate 10 may additionally include other layers (such as, but not limited to, dielectric material layers), and the

positive contact surfaces

26N and 28N of the

electrodes

26 and 28 contact the driving substrate 10 through these layers, which still belongs to the above-mentioned direct contact aspect. Furthermore, the method is simple. In some embodiments,

electrodes

26 and 28 are located between bond pads 12-1 and 12-2. Also, in some embodiments, isolation structure 18 is located between

electrodes

26 and 28. The isolation structure 18 can be used to prevent the

electrodes

26 and 28 from contacting each other during the (thermal) bonding process to cause short circuit.

As shown in fig. 1B, the micro light emitting diode structure 20 is laterally connected to the bonding pads 12-1 and 12-2 on the driving substrate 10 through the side contact surfaces 26S and 28S of the

electrodes

26 and 28, respectively. Therefore, when the micro light emitting diode structure 20 fails, the contact surface of the electrode 26 with the bonding pad 12-1 (i.e., the side contact surface 26S of the electrode 26) and the contact surface of the electrode 28 with the bonding pad 12-2 (i.e., the side contact surface 28S of the electrode 28) may be irradiated with the laser LS from the rear surface 10B of the driving substrate 10 to peel off the failed micro light emitting diode 20. However, in other embodiments not shown, the laser LS may also irradiate the aforementioned contact surface from the front side of the drive substrate 10.

Since the bonding pads 12-1 and 12-2 are only locally fused at the contact surfaces with the

electrodes

26 and 28, the bonding pads 12-1 and 12-2 can still be reused after the micro light emitting diode structure 20 is removed. That is, it is not necessary to reserve additional space above the driving substrate 10 for disposing additional bonding pads or rework bonding pads. In addition, the space after removing the micro led structure 20 can directly accommodate (connect) a new micro led structure.

Fig. 2 is a partial cross-sectional view illustrating the micro led display panel 102 according to an embodiment of the disclosure. Similarly, some components of the micro led display panel 102 have been omitted in fig. 2 in order to more clearly show the technical features of the embodiments of the present disclosure.

Referring to fig. 2, the micro led display panel 102 has a structure similar to that of the micro led display panel 100 shown in fig. 1B, and the main difference is that the micro led structure 20 'of the micro led display panel 102 shown in fig. 2 further includes a planarization layer 29, and the planarization layer 29 is disposed on a side of the micro led structure 20' facing the driving substrate 10. As shown in fig. 2, the planarization layer 29 has a hole 29O, and a portion of the electrode 26 and a portion of the electrode 28 are located in the hole 29O.

The electrode 26 has a body portion 26-1 and an extension portion 26-2, and the extension portion 26-2 connects the body portion 26-1 and extends to a surface 29S of the flat layer 29 facing the driving substrate through the hole 29O. Similarly, the electrode 28 has a body portion 28-1 and an extension portion 28-2, and the extension portion 28-2 connects the body portion 28-1 and extends to a surface 29S of the flat layer 29 facing the driving substrate via the hole 29O.

In other words, in fig. 2, the two electrodes (26, 28) are laterally connected to the corresponding bond pads (12-1, 12-2) by the side contact faces (26S, 28S) of their extensions (26-2, 28-2), respectively. In this embodiment, the bonding pads 12 (e.g., 12-1 or 12-2) are in direct contact with the extensions (26-2, 28-2) of the two electrodes (26, 28) of the micro light emitting diode structure 20'.

Since the height (i.e., the lateral ohmic contact area) of the body portions (26-1, 28-1) of the electrodes (26, 28) is limited as the micro-led structure 20' is scaled down, in the embodiment of fig. 2, the extensions (26-2, 28-2) help to enlarge the contact area between the electrodes (26, 28) and the two bonding pads (12-1, 12-2), thereby ensuring bonding yield while optimizing the electroluminescent efficiency.

In some embodiments, the orthographic projection of the extended portion 26-2 of the electrode 26 on the drive substrate 10 completely covers the orthographic projection of the body portion 26-1 of the electrode 26 on the drive substrate 10. Similarly, in some embodiments, the orthographic projection of the extended portion 28-2 of the electrode 28 on the drive substrate 10 completely covers the orthographic projection of the body portion 28-1 of the electrode 28 on the drive substrate 10.

Fig. 3 is a partial cross-sectional view illustrating a micro led display panel 104 according to another embodiment of the present disclosure. Fig. 4 is a partial cross-sectional view illustrating a micro led display panel 106 according to another embodiment of the present disclosure. Fig. 5 is a partial cross-sectional view illustrating a micro led display panel 108 according to another embodiment of the disclosure. Fig. 6 is a partial cross-sectional view illustrating a micro light emitting diode display panel 110 according to another embodiment of the present disclosure. Similarly, in order to more clearly show the technical features of the embodiments of the present disclosure, some components of the micro led display panel 104, the micro led display panel 106, the micro led display panel 108 and the micro led display panel 110 have been omitted in fig. 3 to 6.

Referring to fig. 3, the micro led display panel 104 has a similar structure to the micro led display panel 102 shown in fig. 2, and the main difference is that the bonding pad 12 (e.g., the bonding pad 12-1 or the bonding pad 12-2) of the micro led display panel 104 shown in fig. 3 is disposed on the passivation layer 16. Specifically, bond pad 12 (e.g., bond pad 12-1 or bond pad 12-2) is disposed over top surface 16T of passivation layer 16 and in direct contact with passivation layer 16.

Referring to fig. 4, the micro led display panel 106 has a structure similar to the micro led display panel 104 shown in fig. 3, and the main difference is that the bonding pad 12 (e.g., the bonding pad 12-1 or the bonding pad 12-2) of the micro led display panel 106 shown in fig. 4 has a protrusion 12P, and the protrusion 12P can further increase the contact area between the bonding pad 12 (e.g., the bonding pad 12-1 or the bonding pad 12-2) and (the extension 26-2 of) the electrode 26 or (the extension 28-2 of) the electrode 28.

Referring to fig. 5, the micro led display panel 108 has a structure similar to that of the micro led display panel 102 shown in fig. 2, and the main difference is that the bonding pad 12 (e.g., the bonding pad 12-1 or the bonding pad 12-2) of the micro led display panel 108 shown in fig. 5 is disposed between the driving substrate 10 and the passivation layer 16. Specifically, the bonding pad 12 (e.g., the bonding pad 12-1 or the bonding pad 12-2) is disposed on the bottom surface 16B of the passivation layer 16, and is in direct contact with the driving substrate 10 and the passivation layer 16.

Referring to fig. 6, the micro led display panel 110 has a structure similar to that of the micro led display panel 102 shown in fig. 2, and the main difference is that one bonding pad 12 (e.g., bonding pad 12-1) of the micro led display panel 110 shown in fig. 6 is disposed on the passivation layer 16, and the other bonding pad 12 (e.g., bonding pad 12-2) is disposed between the driving substrate 10 and the passivation layer 16. Specifically, the bonding pad 12-1 is disposed on the top surface 16T of the passivation layer 16 and in direct contact with the passivation layer 16, and the bonding pad 12-2 is disposed on the bottom surface 16B of the passivation layer 16 and in direct contact with the driving substrate 10 and the passivation layer 16.

In summary, in the micro led display panels (104, 106,108, and 110) of fig. 3 to 6, the bonding pads 12 may be distributed at positions corresponding to the wiring layer 14 in fig. 2. In other words, since the present disclosure adopts a lateral connection structure and can be reused after the laser trimming process, the bonding pad 12 can also refer to a portion of the circuit layout (layout) of the wiring layer 14 in the embodiment shown in the foregoing figures, and is not limited to the independent component shown in fig. 2.

Fig. 7 is a partial cross-sectional view illustrating the micro led display panel 112 according to an embodiment of the disclosure. Fig. 8 is a partial cross-sectional view illustrating a micro led display panel 114 according to another embodiment of the present disclosure. Similarly, in fig. 7 and 8, some components of the micro led display panel 112 and the micro led display panel 114 have been omitted to show technical features of the embodiments of the disclosure more clearly.

Referring to fig. 7, the micro led display panel 112 has a similar structure to the micro led display panel 100 shown in fig. 1B, and is mainly different in that the electrodes 26 'and 28' of the micro led display panel 112 shown in fig. 7 have overlapping regions (i.e., rounded corners enclosed by dotted lines in fig. 7), respectively, such that orthographic projections of the electrodes 26 'and 28' on the driving substrate 10 partially overlap with orthographic projections of the corresponding bonding pads 12 (i.e., the bonding pads 12-1 and 12-2) on the driving substrate 10.

In some embodiments, an orthographic projection of the electrode 26 'on the drive substrate 10 and an orthographic projection of the corresponding bond pad 12 (i.e., bond pad 12-1) on the drive substrate 10 have an overlapping area, and this overlapping area accounts for less than 30% of an area of the orthographic projection of the electrode 26' on the drive substrate 10. Similarly, in some embodiments, the overlapping area of the orthographic projection of the electrode 28 'on the drive substrate 10 and the orthographic projection of the corresponding bond pad 12 (i.e., bond pad 12-2) on the drive substrate 10 accounts for less than 30% of the area of the orthographic projection of the electrode 28' on the drive substrate 10.

Generally, the electrodes of the micro light emitting diodes may be easily displaced horizontally when being bonded to bumps (e.g., bonding pads) on the substrate. In the embodiment shown in fig. 7, since each micro led structure 20 is laterally (or substantially vertically) connected to the corresponding bonding pads 12-1 and 12-2 on the driving substrate 10 through the side contact surfaces 26S and 28S of the electrodes 26 'and 28', respectively, the bonding pads 12-1 and 12-2 will automatically adapt to the shapes of the electrodes 26 'and 28' to fill up the gaps therein, so that the electrical conductivity of the micro led structure 20 and the driving substrate 10 is not affected by horizontal displacement.

The shape of the overlapping area of electrode 26 'and electrode 28' (i.e., the rounded corner encircled by the dashed line in fig. 7) is, for example, due to the patterned distance of bonding pad 12-1 and bonding pad 12-2 (i.e., the shortest distance of bonding pad 12-1 and bonding pad 12-2 in the horizontal direction) being slightly smaller than the boundary width of electrode 26 'and electrode 28' (i.e., the largest distance of electrode 26 'and electrode 28' in the horizontal direction), such that micro light emitting diode structure 20 will naturally press bonding pad 12-1 and bonding pad 12-2 to form the overlapping area during the pressing process. In other words, it means that there is intimate contact between both electrodes (i.e., electrode 26 'and electrode 28') and the bond pads (i.e., bond pad 12-1 and bond pad 12-2).

Therefore, in embodiments of the present disclosure, shortening the distance between the bond pads (e.g., bond pad 12-1 and bond pad 12-2) does not increase the risk of shorting because the bond pads may be separated by micro light emitting diode structures 20. In contrast, in a typical micro led display panel, since the electrodes of the micro leds are bonded to the bumps (e.g., bonding pads) on the substrate in a front-side manner (i.e., in a forward direction), the foregoing effect cannot be achieved, and the short circuit risk is easily increased by shortening the pitch of the bumps.

Referring to fig. 8, the micro led display panel 114 has a similar structure to the micro led display panel 100 shown in fig. 1B, and mainly differs therefrom in that the side contact surface 26S of the electrode 26 ″ of the micro led display panel 114 shown in fig. 8, which is laterally connected to the corresponding bonding pad 12 (i.e., the bonding pad 12-1), is an inclined surface. Similarly, the side contact surface 28S of the electrode 28 ″ that laterally connects with the corresponding bonding pad 12 (i.e., bonding pad 12-2) is also a bevel surface.

As shown in fig. 8, in some embodiments, the pinch θ 1 between the side contact surface 26S of the electrode 26 ″ and the drive substrate 10 is greater than about 45 degrees and less than about 90 degrees. Similarly, in some embodiments, the included angle θ 2 between the side contact surface 28S of the electrode 28 ″ and the driving substrate 10 is greater than about 45 degrees and less than about 90 degrees. In the embodiment shown in fig. 8, the included angle θ 1 is the same as the included angle θ 2, but the embodiment of the disclosure is not limited thereto. In some other embodiments, angle θ 1 is different than angle θ 2.

Fig. 9-13 show different examples of the bonding pads 12 (including the bonding pad 12-1 and the bonding pad 12-2). In addition, to more clearly show the correspondence of bond pad 12-1 to bond pad 12-2, passivation layer 16 is also shown in fig. 9-13. It is noted that not all micro led display panels need to include the passivation layer 16.

Referring to fig. 9, the bonding pads 12-1 and 12-2 are linear in shape, and the bonding pads 12-1 and 12-2 are disposed in pairs. In the top view of fig. 9, the bonding pad 12-1 and the bonding pad 12-2 are centrosymmetric (centrosymmetric). When the micro led structure 20 is bonded to the driving substrate 10, even if an alignment error occurs between the two (for example, as shown in fig. 9), the bonding pads 12-1 and 12-2 can still be laterally connected to the

electrodes

26 and 28. That is, the bonding pads 12-1 and 12-2 have the effect of stopping, and can be used to correct the alignment error caused by horizontal offset or rotation during alignment.

Referring to fig. 10, the bonding pads 12-1 and 12-2 are L-shaped, and the bonding pads 12-1 and 12-2 are disposed in pairs. In the top view shown in fig. 10, the bonding pad 12-1 and the bonding pad 12-2 are centrosymmetric. Similarly, when the micro led structure 20 is bonded to the driving substrate 10, even if an alignment error occurs between the two (for example, as shown in fig. 10), the bonding pads 12-1 and 12-2 can still be laterally connected to the

electrodes

In addition, in fig. 9 and 10, the bonding pad 12-1 and the bonding pad 12-2 are also disposed in an anti-symmetric (anti-symmetric) configuration. That is, in the layout area of the driving substrate 10, the orthographic projection patterns of the bonding pads 12-1 and 12-2 are inverted from each other on the basis of the center lines of the bonding pads.

Fig. 11-13 omit the electrodes 26 and 28 (and the micro led structure 20), and the effect of the stops generated by the bonding pads 12-1 and 12-2 in fig. 11-13 will not be repeated.

Referring to fig. 11, the bonding pads 12-1 and 12-2 are shaped like a square (halo square), and the bonding pads 12-1 and 12-2 are provided in pairs. In the top view of fig. 11, the bonding pads 12-1 and 12-2 are axisymmetric (axial symmetry) and centrosymmetric.

Referring to fig. 12, the bonding pads 12-1 and 12-2 are U-shaped with the openings of the U-shapes facing each other, and the bonding pads 12-1 and 12-2 are provided in pairs. In the top view of fig. 12, the bonding pads 12-1 and 12-2 are axisymmetrical and centrosymmetric.

Referring to fig. 13, the bonding pads 12-1 and 12-2 are linear in shape, and the bonding pads 12-1 and 12-2 are disposed in pairs. In the top view of fig. 13, the bonding pads 12-1 and 12-2 are axisymmetric and centrosymmetric.

As can be seen from the above paragraphs and the description of fig. 9 to 13, since the micro light emitting diode and the driving substrate are bonded by positive pressure, there is a possibility that an error in horizontal displacement may occur due to various factors when aligning the positions. In the present disclosure, since the bonding pads 12-1 and 12-2 are disposed at the sides of the electrodes 26 and 28 (also in the horizontal direction), even if there is the error, the bonding yield of the led structure is not affected. Even further, for example, in fig. 9 and 10, horizontal displacement or rotation of

electrodes

26 and 28 can increase the contact area with bonding pads 12-1 and 12-2.

As described above, in the embodiment of the present disclosure, since each micro light emitting diode structure is laterally connected to the bonding pad on the driving substrate through the side contact surface of the electrode, when the contact surface of the electrode and the bonding pad is irradiated with laser light (for example, from the back surface of the driving substrate) to peel off the failed micro light emitting diode, the bonding pad is locally melted only at the contact surface. Therefore, the bonding pads can be reused without reserving other space for arranging additional bonding pads or manufacturing the bonding pads again. In addition, the space of the removed micro-led structure can directly accommodate (bond) the new micro-led structure.

The components of several embodiments are summarized above so that those skilled in the art to which the disclosure pertains can more clearly understand the aspects of the embodiments of the disclosure. Those skilled in the art should appreciate that they may readily use the disclosed embodiments as a basis for designing or modifying other processes and structures for carrying out the same purposes and/or achieving the same advantages of the embodiments introduced herein. Those skilled in the art should also realize that such equivalent constructions do not depart from the spirit and scope of the present disclosure, and that they may make various changes, substitutions, and alterations herein without departing from the spirit and scope of the present disclosure. Therefore, the protection scope of the present disclosure should be determined by the claims. In addition, although the present disclosure has been described with reference to several preferred embodiments, it is not intended to limit the present disclosure.

Reference throughout this specification to features, advantages, or similar language does not imply that all of the features and advantages that may be realized with the present disclosure should be or are in any single embodiment of the disclosure. Rather, language referring to the features and advantages is understood to mean that a specific feature, advantage, or characteristic described in connection with an embodiment is included in at least one embodiment of the present disclosure. Thus, discussion of the features and advantages, and similar language, throughout this specification may, but do not necessarily, refer to the same embodiment.

Furthermore, the described features, advantages, and characteristics of the disclosure may be combined in any suitable manner in one or more embodiments. One skilled in the relevant art will recognize, in light of the description herein, that the present disclosure may be practiced without one or more of the specific features or advantages of a particular embodiment. In other instances, additional features and advantages may be recognized in certain embodiments that may not be present in all embodiments of the disclosure.

Claims

1. A micro light emitting diode display panel comprising:

a drive substrate;

a plurality of bonding pads disposed on the driving substrate at intervals; and

a plurality of micro light emitting diode structures electrically connected to the plurality of bonding pads, wherein each of the micro light emitting diode structures comprises:

at least one electrode disposed on a side of each of the micro light emitting diode structures facing the driving substrate, the electrode having a front contact surface facing the driving substrate and a side contact surface laterally connected to one of the bonding pads.

2. The micro light-emitting diode display panel of claim 1, wherein an orthographic projection of the electrode on the driving substrate and an orthographic projection of a corresponding one of the plurality of bonding pads on the driving substrate have an overlapping area, and the overlapping area occupies less than 30% of an area of the orthographic projection of the electrode on the driving substrate.

3. The micro light emitting diode display panel of claim 1, wherein the front contact surface is in direct contact with the driving substrate.

4. The micro light-emitting diode display panel of claim 1, wherein the at least one electrode comprises a first electrode and a second electrode, a side contact surface of the first electrode and a side contact surface of the second electrode are respectively bonded to two of the plurality of bonding pads, and the first electrode and the second electrode are located between the two of the plurality of bonding pads.

5. The micro light-emitting diode display panel of claim 1, wherein each of the micro light-emitting diode structures further comprises:

the flat layer is arranged on one side, facing the driving substrate, of each micro light-emitting diode structure and is provided with at least one hole, and at least one part of the electrode is located in the hole;

wherein the at least one electrode has a body portion and an extension portion connected to the body portion and extending through the hole to a surface of the planar layer facing the driving substrate.

6. The micro light emitting diode display panel of claim 5, wherein an orthographic projection of the extension portion on the driving substrate completely covers an orthographic projection of the body portion on the driving substrate.

7. The micro light-emitting diode display panel of claim 5, wherein the at least one electrode comprises a first electrode and a second electrode, the planarization layer has two holes, the first electrode has a portion located in one of the holes, and the second electrode has a portion located in another of the holes.

8. The micro light-emitting diode display panel of claim 1, wherein the at least one electrode comprises a first electrode and a second electrode, and the micro light-emitting diode display panel further comprises:

and the plurality of isolation structures are arranged on one side of the driving substrate facing the plurality of micro light-emitting diode structures, wherein each isolation structure is positioned between the first electrode and the second electrode.

9. The micro light emitting diode display panel of claim 1, wherein the plurality of bonding pads comprises a first bonding pad and a second bonding pad, the first bonding pad and the second bonding pad are disposed in a pair, and the first bonding pad and the second bonding pad are centrosymmetric in a top view of the micro light emitting diode display panel.

10. The micro light emitting diode display panel of claim 9, wherein the shape of the orthographic projection of the first bonding pad on the driving substrate and the orthographic projection of the second bonding pad on the driving substrate comprises an L shape, a U shape, a square shape or a straight shape.

11. The micro light emitting diode display panel of claim 1, wherein an angle between the side contact surface and the driving substrate is greater than 45 degrees and less than 90 degrees.