CN107623012B

CN107623012B - Display device and forming method thereof

Info

Publication number: CN107623012B
Application number: CN201710061424.2A
Authority: CN
Inventors: 胡顺源
Original assignee: Innolux Corp
Current assignee: Innolux Corp
Priority date: 2016-07-13
Filing date: 2017-01-26
Publication date: 2020-04-28
Anticipated expiration: 2037-01-26
Also published as: CN107623012A

Abstract

The invention discloses a display device and a forming method thereof. The display device includes a first conductive pad disposed on a substrate, wherein a contact area is formed between the first conductive pad and the substrate. The display device also includes a first bonding material disposed on the first conductive pad, wherein the first bonding material has a cross-sectional area in a direction parallel to the substrate surface. The display device further includes a second conductive pad disposed on the first bonding material, and a first light emitting structure disposed on the second conductive pad, wherein a cross-sectional area of the first bonding material is smaller than a contact area of the first conductive pad.

Description

Display device and forming method thereof

Technical Field

The present invention relates to a display device, and more particularly, to a display device in which a light emitting structure is bonded to a substrate by eutectic bonding and a method for forming the same.

Background

In a general packaging process of a display device, eutectic bonding (eutectic bonding) is a relatively stable bonding method, and a eutectic alloy material with a low melting point is used, and can be directly converted from a solid phase to a liquid phase during melting without passing through an equilibrium point of the liquid phase and the solid phase, and the eutectic temperature, i.e., the melting temperature of the eutectic alloy material can be lower than the respective melting points of the metals of the eutectic alloy material.

Although the display devices packaged by eutectic bonding and the methods for forming the same are adequate for their intended purposes, they have not yet completely met the requirements in all aspects, and thus there is still a need for eutectic bonding technology for display devices.

Disclosure of Invention

The embodiment of the invention provides a display device and a forming method thereof. Generally, in the process of eutectic bonding of a plurality of light emitting structures to a substrate, due to the thickness difference between the light emitting structures or the thickness difference between the conductive pads on each light emitting structure, the conductive pads on the light emitting structures or the conductive pads on the light emitting structures with thinner thickness cannot be eutectic bonded with the corresponding conductive pads on the substrate, and if the bonding is performed by a forced pressurization method, the light emitting structures may be damaged or the conductive pads may be short-circuited.

In the eutectic bonding process, more bonding material is extruded from the light emitting structure or the conductive pad with a thicker thickness, and in order to solve the problem, in the embodiment of the invention, the accommodating space is generated between the substrate and the conductive pad on the light emitting structure by reducing the sectional area of the bonding material or patterning the bonding material, so that excessive bonding material generated by extrusion enters the accommodating space to avoid the problem of short circuit between the conductive pads.

In addition, the embodiment of the invention ensures that the distance from the surface of each light emitting structure far away from the substrate to the substrate is consistent when the bonding manufacturing process is stopped by arranging the plurality of spacers with equal height between the substrate and the light emitting structure, and in addition, the spacers are arranged between two adjacent conductive pads on the substrate or the light emitting structure, so that short circuit between two adjacent conductive pads on the substrate or the light emitting structure after the bonding manufacturing process can be avoided.

According to some embodiments, a display device is provided. The display device includes a first conductive pad disposed on a substrate, wherein a contact area is formed between the first conductive pad and the substrate. The display device also includes a first bonding material disposed on the first conductive pad, wherein the first bonding material has a cross-sectional area in a direction parallel to the substrate surface. The display device further includes a second conductive pad disposed on the first bonding material, and a first light emitting structure disposed on the second conductive pad, wherein a cross-sectional area of the first bonding material is smaller than a contact area of the first conductive pad.

According to some embodiments, a display device is provided. The display device includes a first conductive pad disposed on the substrate, a first bonding material disposed on the first conductive pad, and a second conductive pad disposed on the first bonding material. In addition, the display device further comprises a first light emitting structure arranged on the second conductive pad, and a first spacer arranged between the substrate and the first light emitting structure.

According to some embodiments, a method of forming a display device is provided. The method for forming the display device includes forming a first conductive pad on a substrate, wherein a contact area is formed between the first conductive pad and the substrate. The method also includes forming a second conductive pad on the first light emitting structure, forming a first bonding material on the first conductive pad, wherein the first bonding material has a cross-sectional area in a direction parallel to the surface of the substrate, the cross-sectional area of the first bonding material is smaller than the contact area of the first conductive pad, and performing a bonding process to bond the first light emitting structure to the substrate.

According to some embodiments, a method of forming a display device is provided. The display device forming method comprises forming a first conductive pad on a substrate and forming a second conductive pad on a light emitting structure. The method for forming the display device further comprises forming a spacer on the substrate or the light-emitting structure, and forming a coating adhesive on the substrate and the first conductive pad. The method further includes forming a bonding material on the coating glue, wherein the bonding material is embedded in the coating glue, the thickness of the bonding material is larger than that of the spacer, and performing a bonding process to bond the light-emitting structure to the substrate.

According to some embodiments, a method of forming a display device is provided. The display device forming method comprises forming a first conductive pad on a substrate and forming a second conductive pad on a light emitting structure. The method for forming the display device further comprises forming coating glue on the substrate and the first conductive pad, or forming coating glue on the light-emitting structure and the second conductive pad, wherein a gap is arranged in the coating glue. In addition, the forming method of the display device further comprises forming a bonding material on the coating glue, embedding the bonding material into the coating glue, wherein the thickness of the bonding material is larger than that of the gap object, and implementing a bonding manufacturing process to bond the light-emitting structure to the substrate.

Drawings

A more complete understanding of the aspects of the embodiments of the present invention can be obtained from the following detailed description when taken in conjunction with the accompanying drawings. It is noted that, according to industry standard practice, various elements may not be drawn to scale. In fact, the dimensions of the various elements may be arbitrarily increased or reduced for clarity of discussion.

FIGS. 1-2 are cross-sectional views illustrating the formation of a display device;

3A-3C are schematic cross-sectional views illustrating stages in forming a display device according to some embodiments of the invention;

FIG. 4 is a schematic cross-sectional view illustrating a display device according to some embodiments of the invention;

FIGS. 5A-5B are schematic cross-sectional views illustrating intermediate stages in forming a display device, according to some embodiments of the invention;

FIGS. 6A-6F are top views of bonding material on a conductive pad along line A-A or line B-B of FIG. 5A, or along line A '-A' or line B '-B' of the display device of FIG. 5B, according to some embodiments of the present invention;

FIGS. 7A-7D are schematic cross-sectional views illustrating intermediate stages in forming a display device, according to some embodiments of the invention;

FIGS. 8A-8B are schematic cross-sectional views illustrating intermediate stages in forming a display device, according to some embodiments of the invention;

FIGS. 9A-9D are schematic cross-sectional views illustrating intermediate stages in forming a display device, according to some embodiments of the invention;

10A-10B are schematic cross-sectional views illustrating intermediate stages in forming a display device, according to some embodiments of the invention;

11A-11E are cross-sectional views illustrating intermediate stages in forming a display device according to some embodiments of the invention;

12A-12E are cross-sectional views illustrating intermediate stages in forming a display device according to some embodiments of the invention;

fig. 13A-13E are cross-sectional schematic diagrams illustrating intermediate stages in forming a display device according to some embodiments of the invention.

Description of the symbols

100. 200, 300, 400, 500, 700, 800, 900, 1000, 1100, 1200, 1300 to a display device;

101. 201, 301, 401, 501, 701, 801, 901, 1001, 1101, 1201, 1301 to a substrate;

103a, 203a, 303a, 403a, 503a, 703a, 803a, 903a, 1003a, 1103a, 1203a, 1303a to a first conductive pad;

103b, 203b, 303b, 403b, 503b, 703b, 803b, 903b, 1003b, 1103b, 1203b, 1303b, to a third conductive pad;

704a, 804a, 904a, 1004a, 1104a, 1204a, 1304a — first spacers;

704b, 804b, 904b, 1004b, 1104b, 1204b, 1304 b-second spacers;

105a, 205a, 305a, 405a, 505a, 705a, 805a, 905a, 1005a, 1105a, 1205a, 1305a — a first bonding material;

105b, 205b, 305b, 405b, 505b, 705b, 805b, 905b, 1005b, 1105b, 1205b, 1305 b-second bonding material;

107a, 207a, 307a, 407a, 507a, 707a, 807a, 907a, 1007a, 1107a, 1207a, 1307 a-second conductive pads;

107b, 207b, 307b, 407b, 507b, 707b, 807b, 907b, 1007b, 1107b, 1207b, 1307b to fourth pads;

109a, 209a, 309a, 409a, 509a, 709a, 809a, 909a, 1009a, 1109a, 1209a, 1309 a-first light emitting structure;

109b, 209b, 309b, 409b, 509b, 709b, 809b, 909b, 1009b, 1109b, 1209b, 1309 b-second light-emitting structure;

111. 211, 311, 411, 511, 711, 811, 911, 1011, 1111, 1211, 1311 to a linker;

506 a-a first gap;

506 a' to a first hole;

506b to a second gap;

506 b' to a second aperture;

1113. 1213 and 1313-coating adhesive;

1304-spacer;

c-center;

t-thickness.

Detailed Description

The following description provides many different embodiments or examples for implementing the provided display device. Specific examples of the elements and their configurations are described below to simplify the embodiments of the present invention. These are, of course, merely examples and are not intended to be limiting. For example, references in the description to a first element being formed on a second element may include embodiments in which the first and second elements are in direct contact, and may also include embodiments in which additional features are formed between the first and second elements such that the first and second elements are not in direct contact. In addition, embodiments of the present invention may repeat reference numerals and/or letters in the various examples. This repetition is for the purpose of simplicity and clarity and does not in itself dictate a relationship between the various embodiments and/or configurations discussed.

Some variations of the embodiments are described below. Like reference numerals are used to identify like elements in the various figures and described embodiments. It will be understood that additional operations may be provided before, during, and after the methods described below, and that some of the recited operations may be substituted or deleted for other embodiments of the methods.

Fig. 1-2 are cross-sectional views illustrating the formation of

display devices

100 and 200, wherein fig. 1-2 are schematic views illustrating the problem that the conductive pads on the light emitting structures with smaller thickness or the conductive pads on the light emitting structures with smaller thickness in the

display devices

100 and 200 cannot be eutectic bonded with the corresponding conductive pads on the substrate.

As shown in fig. 1, the substrate 101 of the display device 100 has a plurality of first conductive pads 103a and a plurality of third conductive pads 103b, each of the first conductive pads 103a has a respective first bonding material 105a thereon, and each of the third conductive pads 103b has a respective second bonding material 105b thereon. In addition, the display device 100 has a first light emitting structure 109a and a second light emitting structure 109b having different thicknesses, wherein the thickness of the first light emitting structure 109a is smaller than that of the second light emitting structure 109 b.

A plurality of second conductive pads 107a are formed on the bottom surface of the first light emitting structure 109a, and the first light emitting structure 109a and the plurality of second conductive pads 107a located on the bottom surface thereof constitute a first light emitting element; a plurality of fourth conductive pads 107b are formed on the bottom surface of the second light emitting structure 109b, and the second light emitting structure 109b and the plurality of fourth conductive pads 107b located on the bottom surface thereof constitute a second light emitting element. The first light emitting structure 109a and the second light emitting structure 109b are bonded to the substrate 101 by using the joint 111, wherein the first bonding material 105a and the second conductive pad 107a are located in a corresponding relationship in a direction perpendicular to the surface of the substrate 101, and the second bonding material 105b and the fourth conductive pad 107b are located in a corresponding relationship in a direction perpendicular to the surface of the substrate 101.

As shown in fig. 1, since the first light emitting structure 109a and the second light emitting structure 109b have different thicknesses, when the substrate 101 is bonded to the second light emitting structure 109b, the first light emitting structure 109a and the substrate 101 still have a gap therebetween and cannot be completely bonded. At this time, if the terminal 111 is pressed forcibly, the first light emitting structure 109a and the second light emitting structure 109b may be damaged, or the second bonding material 105b may be extruded outward due to over-pressing, so that two adjacent second bonding materials 150b may contact each other to cause a short circuit.

As shown in fig. 2, the display device 200 of fig. 2 has elements similar to those of the display device 100 of fig. 1, and for simplicity of description, they are not repeated here. It is noted that the display device 200 of fig. 2 has the first light emitting structure 209a and the second light emitting structure 209b with the same thickness, but due to the difference in thickness between the second conductive pad 207a and the fourth conductive pad 207b of the display device 200, the display device 200 may have problems similar to those of the display device 100 in the bonding process. Specifically, since the thickness of the second conductive pad 207a of the display device 200 is smaller than that of the fourth conductive pad 207b, when the substrate 201 is bonded to the second light emitting structure 209b, a gap is still formed between the first light emitting structure 209a and the substrate 201, and the bonding cannot be completed. In this case, if the pressure is forcibly applied to the joint 211, the above-described problem occurs.

On the whole, when the thickness of the first light emitting device is not consistent with the thickness of the second light emitting device, the bonding process between the substrate and the first and second light emitting devices cannot be smoothly completed, which is prone to the aforementioned problems.

One of the objectives of the following embodiments is to solve the above-mentioned problems, and the following embodiments illustrate how to solve the above-mentioned problems by taking the display device as an example that includes the first light emitting structure 109a and the second light emitting structure 109b with different thicknesses, but not limited thereto, the display device may also include the first conducting pad 103a and the third conducting pad 103b with different thicknesses, or the second conducting pad 107a and the fourth conducting pad 107b with different thicknesses.

Fig. 3A-3C are cross-sectional views illustrating stages in forming a display device 300, according to some embodiments of the invention.

According to some embodiments, as shown in fig. 3A, a plurality of first conductive pads 303A and a plurality of third conductive pads 303b are formed on the substrate 301. In some embodiments, the substrate 301 may be a substrate formed with a Thin Film Transistor (TFT) array (array). The first conductive pad 303a and the third conductive pad 303b may be formed by a deposition process, such as Chemical Vapor Deposition (CVD), Physical Vapor Deposition (PVD), Atomic Layer Deposition (ALD), Metal Organic Chemical Vapor Deposition (MOCVD), spin coating (spinning), or sputtering, to form a conductive layer, and then patterning the conductive layer to form a plurality of conductive pads by a patterning process, wherein the patterning process includes photolithography and etching processes.

As shown in fig. 3A, a respective first bonding material 305a is formed on each of the first conductive pads 303A, and a respective second bonding material 305b is formed on each of the third conductive pads 303 b. It is noted that the first bonding material 305a and the second bonding material 305b have cross-sectional areas in a direction parallel to the surface of the substrate 101, the first conductive pad 303a and the third conductive pad 303b have contact areas with the substrate 101, and the cross-sectional areas of the first and

second bonding materials

305a, 305b are smaller than the contact areas between the first and third

conductive pads

303a, 303b and the substrate 301, respectively. In some embodiments, the first and

second bonding materials

305a, 305b may be formed using spraying (injecting) or transferring (stamping). The material of the first and

second bonding materials

305a, 305b may be a low melting point metal or alloy material, and In some embodiments, the material of the first and

second bonding materials

305a, 305b may be a eutectic material with a melting point less than 350 ℃, such as a metal alloy of tin (Sn), gallium (Ga), indium (In), gold (Au), zinc (Zn), bismuth (Bi), silver (Ag), the aforementioned alloys, or other suitable materials. In other embodiments, the material of the first and

second bonding materials

305a, 305b is a heatable, electrically conductive curable material. In addition, the materials of the first conductive pad 303a and the third conductive pad 303b may be similar or identical to the first and

second bonding materials

305a, 305b, and are not repeated here for brevity.

On the other hand, as shown in fig. 3A, the first light emitting structure 309a and the second light emitting structure 309b are adsorbed or adhered by the joint 311 of the thermocompression bonding apparatus, and in some embodiments, the first light emitting structure 309a has a smaller thickness than the second light emitting structure 309 b. A plurality of second conductive pads 307a are formed on the bottom surface of the first light emitting structure 309a, the first light emitting structure 309a and the plurality of second conductive pads 307a located on the bottom surface thereof constitute a first light emitting element, a plurality of fourth conductive pads 309b are formed on the bottom surface of the second light emitting structure 309b, and the second light emitting structure 309b and the plurality of fourth conductive pads 309b located on the bottom surface thereof constitute a second light emitting element. In some embodiments, the first and second

light emitting structures

309a, 309b may be Light Emitting Diodes (LEDs). In addition, the fabrication process and material of the second and fourth

conductive pads

307a, 307b may be similar or identical to those of the first and third

conductive pads

303a, 303b, and thus are not repeated herein for brevity.

According to some embodiments, as shown in fig. 3B, a bonding fabrication process is performed to simultaneously bond the first and second light emitting structures 309a, 309B to the substrate 301 through the joints 311 to form the display device 300 under the joints 311. The bonding process is to apply temperature and pressure through the joints 311 to facilitate bonding between the substrate 301 and the first and second

light emitting structures

309a, 309 b. Generally, the temperature applied by the contact 311 is dependent upon the materials used for the first, second, third and fourth

conductive pads

305a, 307a, 305b, 307b and the first and

second bonding materials

305a, 305b, and in some embodiments, the temperature applied by the contact 311 is less than 350 ℃ and is in the range of about 100 ℃ to 300 ℃. In addition, the pressure applied by the joints 311 depends on the number of the

light emitting structures

309a and 309b to be bonded.

As shown in fig. 3A, since the cross-sectional areas of the first and second bonding materials 305a, 305B before bonding are smaller than the contact areas between the first and third conductive pads 303A, 303B and the substrate 101, and the receiving spaces are formed between the first and second conductive pads 303A, 307a and between the third and fourth conductive pads 303B, 307B, after bonding, as shown in fig. 3B, the portion of the second bonding material 305B under the thicker second light emitting structure 309B extruded by pressurization in the bonding process does not contact with the surrounding other conductive elements, thereby avoiding the short circuit problem. Meanwhile, after the bonding process is performed, the first and second

light emitting structures

309a and 309b may be smoothly bonded to the substrate 101. In addition, since the first light emitting structure 309a has a smaller thickness than the second light emitting structure 309B, after bonding, as shown in fig. 3B, the first bonding material 305a under the first light emitting structure 309a has an inwardly concave cross-sectional profile, and the second bonding material 305B under the second light emitting structure 309B has an outwardly convex cross-sectional profile.

Next, as shown in fig. 3C, after the bonding process is performed, the joints 311 are removed. In some embodiments, a passivation layer (not shown) is disposed to cover the display device 300. In addition, another substrate (not shown) is disposed above the first light emitting structure 309a and the second light emitting structure 309b to completely cover the display device 300. As shown in the left side of fig. 3C, after the bonding process is performed and the joint 311 is removed, the cross-sectional area of the first bonding material 305a of the display device 300 is smaller than the contact area between the first conductive pad 303a and the substrate 301. Specifically, the first bonding material 305a has a center c and a thickness t, and the first bonding material 305a has a cross-sectional area in a direction parallel to the surface of the substrate 301, the cross-sectional area being located within a range of 15% of the thickness t above and below the center c of the first bonding material 305 a.

In other words, the first bonding material 305a has a cross section in a direction perpendicular to the substrate 301, in which the first bonding material 305a has an inwardly concave cross-sectional profile within a range of a thickness t of 15% above and below a center c thereof.

Fig. 4 is a schematic cross-sectional diagram illustrating a display device 400, according to some embodiments of the invention.

According to some embodiments, as shown in FIG. 4, the display device 400 has elements similar to those of the display device 300 of FIG. 3B, which are not repeated here for simplicity of description. It is noted that the display device 400 of fig. 4 has the first light emitting structure 409a and the second light emitting structure 409b with the same thickness, and the second conductive pad 407a and the fourth conductive pad 407b with different thicknesses, specifically, the thickness of the second conductive pad 407a is smaller than that of the fourth conductive pad 407 b. In addition, after the bonding process is performed, the joints 411 are removed to form the display device 400.

Similar to the manufacturing process of the display device 300, the display device 400 has a technical feature that the cross-sectional area of the first and second bonding materials 405a and 405b is smaller than the contact area between the first and third

conductive pads

403a and 403b and the substrate 401 before the bonding process is performed, and both the first and second

light emitting structures

409a and 409b can be smoothly bonded to the substrate 401. In addition, since the second conductive pad 407a has a thinner thickness than the fourth conductive pad 407b, the first bonding material 405a located under the second conductive pad 407a has an inwardly concave cross-sectional profile, and the second bonding material 405b located under the fourth conductive pad 407b has an outwardly convex cross-sectional profile.

Fig. 5A-5B are cross-sectional schematic diagrams illustrating intermediate stages in forming a display device 500 according to some embodiments of the invention. The display device 500 has elements similar to those of the display device 300 of FIG. 3B, which are not repeated here for simplicity of description.

According to some embodiments, as shown in fig. 5A, patterned first and second bonding materials 505A, 505b are disposed on the first and third

conductive pads

503a, 503b, respectively. It is noted that the patterned first and

second bonding materials

505a, 505b have gaps or holes therein. In some embodiments, as shown in fig. 5A, the patterned first bonding material 505A has first gaps 506a therein, and the patterned second bonding material 505b has second gaps 506b therein.

Next, as shown in fig. 5B, a bonding process is performed to bond the first and second light emitting structures 509a and 509B to the substrate 501 through the joint 511 at the same time to form the display device 500 under the joint 511, wherein the first gap 506a and the second gap 506B are compressed to be reduced into a first hole 506a 'and a second hole 506B', respectively. In other embodiments, the first gap 506a and the second gap 506b are still elongated gaps instead of holes after the bonding process is performed. In addition, after the bonding fabrication process is performed, the joints 511 are removed to form the display device 500.

The display device 500 is the same as the display device 300 in that the cross-sectional area of the first and

second bonding materials

505a and 505b is smaller than the contact area between the first and third

conductive pads

503a and 503b and the substrate 501 before the bonding process is performed. In addition, compared to the display device 300, since the first and

second bonding materials

505a and 505b of the display device 500 have gaps or holes inside, and the first and second

conductive pads

503a and 507a and the third and fourth

conductive pads

503b and 507b have larger accommodating spaces, after the bonding process is performed, the first and second

light emitting structures

509a and 509b can be smoothly bonded to the substrate 501 without causing device damage or short circuit.

In addition, as shown in the left side of fig. 5B, the cross-sectional area of the first bonding material 505a of the display device 500 is smaller than the contact area between the first conductive pad 503a and the substrate 501. Specifically, the line a '-a' is a center line of the first bonding material 505a in a direction parallel to the surface of the substrate 501, the first bonding material 505a has a thickness t, and the cross-sectional position of the cross-sectional area of the first bonding material 505a is within a range of 15% of the thickness t above and below the line a '-a'.

In other words, the first bonding material 505a has a cross section in a direction perpendicular to the substrate 501, and the cross section has a profile in which the first bonding material 505a is recessed inward in a range of 15% of the thickness t above and below the line a '-a'.

Fig. 6A-6C are top views illustrating bonding material on conductive pads along line a-a or line B-B of fig. 5A, or along line a '-a' or line B '-B' of the display device 500 of fig. 5B, in accordance with some embodiments of the present invention. It is noted that the embodiments of the present invention are not limited thereto.

In some embodiments, as shown in figures 6A and 6B, the conductive pad 503 may be circular or square (the conductive pad 503 may comprise the first and third conductive pads 503a, 503B), and the bonding material 505 on the conductive pad 503 has a substantially circular or square profile (the bonding material 505 may comprise the first and second bonding materials 505a, 505B). Notably, because the bonding material 505 has a gap 506 therein (the gap 506 may include the first and second gaps 506a, 506B), the gap 506 exposes a portion of the conductive pad 503 beneath the bonding material 505 in a top view along line a-a or line B-B of fig. 5A, or along line a '-a' or line B '-B' of the display device 500 of fig. 5B.

In other embodiments, as shown in fig. 6C and 6D, there is more than one gap 506 within the bonding material 505. The bonding material 505 shown in fig. 6A, 6B, 6C, and 6D may be formed by a patterning fabrication process including a photolithography and etching fabrication process.

In yet another embodiment, as shown in fig. 6E and 6F, a plurality of bonding materials 505 are disposed on a single conductive pad 503, such that a space is formed between the bonding materials 505 on the single conductive pad 503. In other embodiments, as shown in fig. 6E and 6F, a plurality of spherical bonding materials 505 may be disposed on the single conductive pad 503, and the bonding materials 505 may be conductive particles such as solder balls.

Fig. 7A-7D are cross-sectional schematic diagrams illustrating intermediate stages in forming a display device 700, according to some embodiments of the invention.

According to some embodiments, as shown in fig. 7A, a plurality of first conductive pads 703a, a plurality of third conductive pads 703b, a plurality of first spacers 704a, and a plurality of second spacers 704b are formed on a substrate 701. Specifically, at least one first spacer 704a is disposed in a region to be subsequently bonded to the first light emitting element, and at least one second spacer 704b is disposed in a region to be subsequently bonded to the second light emitting element. In some embodiments, at least one spacer is disposed in a region to be subsequently bonded to the first light emitting element and a region to be subsequently bonded to the second light emitting element. Further, a spacer may be provided between a region to be subsequently bonded to the first light emitting element and a region to be bonded to the second light emitting element. The materials and fabrication processes of the first and third

conductive pads

703a, 703b can be similar or identical to those of the first and third

conductive pads

303a, 303b of the display device 300, and therefore, for brevity, are not repeated here. In some embodiments, the first and

second spacers

704a, 704b may be formed by photolithography and etching fabrication processes and have the same thickness. In addition, the first and

second spacers

704a, 704b may be an insulating material, such as silicon oxide, silicon oxynitride, silicon nitride, a polymer material that can be etched by development, or a combination thereof.

Subsequently, as shown in fig. 7B, patterned first and second bonding materials 705a and 705B are disposed on the first and third conductive pads 703a and 703B, respectively. Notably, the thickness of the first and

second bonding materials

705a, 705b is greater than the thickness of the first and

second spacers

704a, 704 b. In addition, the fabrication process and material of the first and

second bonding materials

705a and 705b may be similar to or the same as the first and

second bonding materials

305a and 305b of the light emitting structure 300, and are not repeated herein for brevity.

Next, as shown in fig. 7C, the first light emitting structure 709a and the second light emitting structure 709b are adsorbed or adhered by the joint 711, and the thickness of the first light emitting structure 709a is smaller than that of the second light emitting structure 709 b. A plurality of second conductive pads 707a are formed on the bottom surface of the first light emitting structure 709a, the first light emitting structure 709a and the plurality of second conductive pads 707a on the bottom surface thereof constitute a first light emitting element, a plurality of fourth conductive pads 709b are formed on the bottom surface of the second light emitting structure 709b, and the second light emitting structure 709b and the plurality of fourth conductive pads 707b on the bottom surface thereof constitute a second light emitting element. In some embodiments, the first and second

light emitting structures

709a, 709b may be Light Emitting Diodes (LEDs). In addition, the fabrication process and material of the second and fourth

conductive pads

707a, 707b may be similar or identical to the second and fourth

conductive pads

307a, 307b of the display device 300, and therefore, for brevity, will not be repeated here.

According to some embodiments, as shown in fig. 7D, a bonding fabrication process is performed to simultaneously bond the first and second

light emitting structures

709a and 709b to the substrate 701 through the joints 711 to form the display device 700 under the joints 711. The temperature and pressure applied by the joint 711 are not repeated here for the sake of brevity, as are the temperatures and pressures applied by the joint 311 of fig. 3B. When the thicker second light emitting structure 709b contacts the second spacer 704b, the bonding process is stopped. At this time, the thickness of the first bonding material 705a is greater than the thickness of the second bonding material 705b, the thickness of the first spacer 704a is less than the sum of the thicknesses of the first conductive pad 703a, the first bonding material 705a and the second conductive pad 707a, and the thickness of the second spacer 704b is equal to the sum of the thicknesses of the third conductive pad 703b, the second bonding material 705b and the fourth conductive pad 707 b. In addition, after the bonding fabrication process is performed, the joints 711 are removed to form the display device 700.

Before the bonding process is performed, since the thickness of the first and

second bonding materials

705a and 705b is greater than the thickness of the first and

second spacers

704a and 704b, when the thicker second light emitting structure 709b contacts the second spacer 704b, it is ensured that the first and second

light emitting structures

709a and 709b are smoothly bonded to the substrate 701.

Moreover, since the first and

second spacers

704a and 704b with the same thickness are disposed on the substrate 701, when the bonding process is stopped, the distance between the surface of the substrate 701 close to the first light-emitting structure 709a and the surface of the first light-emitting structure 709a away from the substrate 701 is equal to the distance between the surface of the substrate 701 close to the second light-emitting structure 709b and the surface of the second light-emitting structure 709b away from the substrate 701, and the overall thickness of the display device 700 can be controlled more precisely by disposing the first and

second spacers

704a and 704b with the same thickness.

On the other hand, the first and

second spacers

704a, 704b prevent the bonding materials on the different conductive pads from contacting each other, thereby avoiding the short circuit problem.

Fig. 8A-8B are cross-sectional schematic diagrams illustrating intermediate stages in forming a display device 800, according to some embodiments of the invention. Fig. 8A-8B have elements similar to those of fig. 7C-7D, which are not repeated here for simplicity of description.

In some embodiments, fig. 8A differs from fig. 7C in the location of the first and

second spacers

804a, 804b, which are disposed on the first and second

light emitting structures

809a, 809b, respectively, as shown in fig. 8A. At least one first spacer 804a is disposed on each light emitting structure 809a, and at least one second spacer 804b is disposed on each light emitting structure 809 b. Further, similar to fig. 7C, the first and

second bonding materials

805a, 805b of fig. 8A have a thickness greater than the thickness of the first and

second spacers

804a, 804 b.

Continuing to the foregoing, as shown in fig. 8B, a bonding fabrication process is performed to simultaneously bond the first and second light emitting structures 809a, 809B to the substrate 801 through the joint 811 to form the display device 800 below the joint 811. When the second spacer 804b on the thicker second light emitting structure 809b contacts the substrate 801, the bonding process is stopped. At this time, the thickness of the first bonding material 805a is greater than that of the second bonding material 805b, the thickness of the first spacer 804a is less than the sum of the thicknesses of the first conductive pad 803a, the first bonding material 805a and the second conductive pad 807a, and the thickness of the second spacer 804b is equal to the sum of the thicknesses of the third conductive pad 803b, the second bonding material 805b and the fourth conductive pad 807 b. In addition, after the bonding fabrication process is performed, the joints 811 are removed to form the display device 800.

Similar to the display device 700, the display device 800 can ensure smooth bonding of the first and second

light emitting structures

809a, 809b to the substrate 801 and precisely control the overall thickness of the display device 800 by providing the first and

second bonding materials

805a, 805b with a thickness greater than the thickness of the first and

second spacers

804a, 804b and providing the first and

second spacers

804a, 804b with the same thickness before performing the bonding process.

Fig. 9A-9D are cross-sectional schematic diagrams illustrating intermediate stages in forming a display device 900 according to some embodiments of the invention.

According to some embodiments, as shown in fig. 9A, a plurality of first conductive pads 903a, a plurality of third conductive pads 903b, a plurality of first spacers 904a, and a plurality of second spacers 904b are formed on a substrate 901. Specifically, a first spacer 904a is disposed on each side of each first pad 903a, and a second spacer 904b is disposed on each side of each second pad 903 b. The materials and fabrication processes of the first and third

conductive pads

903a, 903b may be similar to or the same as those of the first and third

conductive pads

303a, 303b of the display device 300, and the materials and fabrication processes of the first and

second spacers

904a, 904b may be similar to those of the first and second spacers 304a, 304b of the display device 300, which are not repeated here for brevity.

Fig. 9A differs from fig. 7A in the location of the first and

second spacers

904a, 904 b. As shown in fig. 9A, the first and

second spacers

904a, 904b may be in contact with the first and third

conductive pads

903a, 903b, respectively, and a portion of the first and

second spacers

904a, 904b may overlie a portion of the first and third

conductive pads

903a, 903b, respectively. In other embodiments, only one first spacer 904a may be disposed between two adjacent first pads 903a because the first pads 903a are spaced apart from each other by too small a distance; similarly, only one second spacer 904b may be disposed between two adjacent third conductive pads 903 b.

Subsequently, as shown in fig. 9B, patterned first and second bonding materials 905a and 905B are disposed on the first and third pads 903a and 903B, respectively. Notably, the thickness of the patterned first and

second bonding materials

905a, 905b is greater than the thickness of the first and

second spacers

904a, 904 b. In some embodiments, the patterned first bonding material 905a may contact the first spacers 904a and the patterned second bonding material 905b may contact the second spacers 904 b. In other embodiments, the patterned first bonding material 905a may not contact the first spacers 904a and the patterned second bonding material 905b may not contact the second spacers 904 b.

Next, as shown in fig. 9C, the first light emitting structure 909a and the second light emitting structure 909b are attached or adhered through the joint 911, and the thickness of the first light emitting structure 909a is smaller than that of the second light emitting structure 909 b. A plurality of second conductive pads 907a are formed on the bottom surface of the first light emitting structure 909a, and a plurality of fourth conductive pads 909b are formed on the bottom surface of the second light emitting structure 909 b. The fabrication process and materials of the first and second

light emitting structures

909a and 909b may be similar to or the same as those of the first and second

light emitting structures

309a and 309b of the display device 300, and the fabrication process and materials of the second and fourth

conductive pads

907a and 907b may be similar to or the same as those of the second and fourth

conductive pads

307a and 307b of the light emitting structure 300, which are not repeated herein for brevity.

According to some embodiments, as shown in fig. 9D, a bonding fabrication process is performed to simultaneously bond the first and second

light emitting structures

909a, 909b to the substrate 901 through the joint 911 to form the display device 900 below the joint 911. The temperatures and pressures applied by the connector 911 are the same as those applied by the connector 311 of fig. 3B and will not be repeated here for the sake of brevity. When the thicker second light emitting structure 909b contacts the second spacer 904b, the bonding process is stopped. At this time, the thickness of the first bonding material 905a is greater than that of the second bonding material 905b, the thickness of the first spacer 904a is less than the sum of the thicknesses of the first conductive pad 903a, the first bonding material 905a and the second conductive pad 907a, and the thickness of the second spacer 904b is equal to the sum of the thicknesses of the third conductive pad 903b, the second bonding material 905b and the fourth conductive pad 907 b. In some embodiments, after performing the bonding process, the thickness of the portion of the first spacer 904a overlying the first conductive pad 903a is less than the thickness of the first bonding material 905 a. In addition, after the bonding process is performed, the connector 911 is removed to form the display device 900.

By providing the first and

second spacers

904a and 904b, the first and second

light emitting structures

909a and 909b can be smoothly bonded to the substrate 901, and the overall thickness of the display device 900 can be controlled more precisely. In addition, since the first and

second spacers

904a, 904b have a portion located on the first conductive pad 903a or the third conductive pad 903b, the first and

second bonding materials

905a, 905b can be ensured to occupy the space inside during the bonding process, thereby further preventing the first and

second bonding materials

905a, 905b from being extruded outwards due to extrusion, which causes a short circuit problem.

Fig. 10A-10B are cross-sectional schematic diagrams illustrating intermediate stages in forming a display device 1000, according to some embodiments of the invention. Fig. 10A-10B have elements similar to those of fig. 9C-9D, which are not repeated here for simplicity of description.

In some embodiments, fig. 10A differs from fig. 9C in the location of the first and

second spacers

1004a, 1004b, as shown in fig. 10A, the first and

second spacers

1004a, 1004b are disposed on the first and second

light emitting structures

1009a, 1009b, respectively. Moreover, only one first spacer 1004a is disposed between two adjacent third conductive pads 1007a, and two ends of the first spacer 1004a respectively have a portion covering the two adjacent third conductive pads 1007 a. Only one second spacer 1004b is disposed between two adjacent fourth pads 1007b, and two ends of the second spacer 1004b respectively have a portion covering the two adjacent fourth pads 1007 b.

In other embodiments, more than one first spacer 1004a may be disposed between two adjacent third pads 1007a, and more than one second spacer 1004b may be disposed between two adjacent fourth pads 1007 b. Further, similar to fig. 9C, the thickness of the first and

second bonding materials

1005a, 1005b of fig. 10A is greater than the thickness of the first and

second spacers

1004a, 1004 b.

Next, as shown in fig. 10B, a bonding process is performed to simultaneously bond the first and second light emitting structures 1009a and 1009B to the substrate 1001 through the joint 1011, so as to form the display device 1000 below the joint 1011. When the second spacer 1004b on the thicker second light emitting structure 1009b contacts the substrate 1001, the bonding process is stopped. At this time, the thickness of the first bonding material 1005a is greater than that of the second bonding material 1005b, the thickness of the first spacer 1004a is less than the sum of the thicknesses of the first conductive pad 1003a, the first bonding material 1005a and the second conductive pad 1007a, and the thickness of the second spacer 1004b is equal to the sum of the thicknesses of the third conductive pad 1003b, the second bonding material 1005b and the fourth conductive pad 1007 b. In some embodiments, after the bonding process is performed, the thickness of the portion of the first spacer 1004a overlying the first conductive pad 1003a is less than the thickness of the first bonding material 1005 a. In addition, after the bonding process is performed, the joints 1011 are removed to form the display device 1000.

Similar to the display device 900, the display device 1000 can ensure that the first and second

light emitting structures

1009a and 1009b are smoothly bonded to the substrate 1001 by the first and

second spacers

1004a and 1004b, and the overall thickness of the display device 1000 can be controlled more precisely. In addition, since the first and

second spacers

1004a and 1004b have a portion located on the second conductive pad 1007a or the third conductive pad 1007b, the first and

second bonding materials

1005a and 1005b can be ensured to occupy the space inside during the bonding process, thereby further preventing the first and

second bonding materials

1005a and 1005b from being extruded outward due to extrusion and causing short circuit.

Fig. 11A-11E are cross-sectional schematic diagrams illustrating intermediate stages in forming a display device 1100 according to some embodiments of the invention.

According to some embodiments, as shown in fig. 11A, a plurality of first conductive pads 1103a, a plurality of third conductive pads 1103b, a plurality of first spacers 1104a, and a plurality of second spacers 1104b are formed on a substrate 1101. The materials and fabrication processes of the first and third

conductive pads

1103a and 1103b may be similar to or the same as those of the first and third

conductive pads

303a and 303b of the display device 300, and the materials and fabrication processes of the first and

second spacers

1104a and 1104b may be similar to those of the first and second spacers 304a and 304b of the display device 300, which are not repeated herein for brevity.

Subsequently, as shown in fig. 11B, the coating 1113 is formed on the substrate 1101, the first conductive pad 1103a and the third conductive pad 1103B. In some embodiments, the coating 1113 is a non-solid insulating material, and the refractive index of the coating 1113 is between air and the light emitting structure, and is in a range of about 1 to about 2.4. In some embodiments, the refractive index of the coating paste 1113 is in the range of about 1.4 to about 1.6. The coating rubber 1113 has the functions of light extraction and protection. In other embodiments, the coating paste 1113 may further cover the first and

second spacers

1104a, 1104 b.

Next, as shown in fig. 11C, the first and

second bonding materials

1105a, 1105b are provided on the coating paste 1113, and a part of the first and

second bonding materials

1105a, 1105b is embedded in the coating paste 1113. Notably, the thickness of the first and

second bonding materials

1105a, 1105b is greater than the thickness of the first and

second spacers

1104a, 1104 b. In some embodiments, the first and

second bonding materials

1105a, 1105b may be spherical conductive particles, such as solder balls or nickel-gold plated metal balls. Further, the first and

second bonding materials

1105a, 1105b are disposed on the coating paste 1113 on the corresponding first and third

conductive pads

1103a, 1103b, respectively, by spraying or transferring.

As shown in fig. 11D, the first light emitting structure 1109a and the second light emitting structure 1109b are adsorbed or adhered by the joint 1111, and the thickness of the first light emitting structure 1109a is smaller than that of the second light emitting structure 1109 b. A plurality of second conductive pads 1107a are formed on the bottom surface of the first light emitting structure 1109a, and a plurality of fourth conductive pads 1107b are formed on the bottom surface of the second light emitting structure 1109 b. The fabrication processes and materials of the first and second

light emitting structures

1109a and 1109b may be similar to or the same as those of the first and second

light emitting structures

309a and 309b of the display device 300, and the fabrication processes and materials of the second and fourth

conductive pads

1107a and 1107b may be similar to or the same as those of the second and fourth

conductive pads

307a and 307b of the light emitting structure 300, which will not be repeated herein for brevity.

According to some embodiments, as shown in fig. 11E, a bonding process is performed to simultaneously bond the first and second

light emitting structures

1109a, 1109b to the substrate 1101 through the joints 1111 to form the display device 1100 under the joints 1111. The temperature and pressure applied by the joint 1111 are the same as those applied by the joint 311 of fig. 3B, and will not be repeated here for the sake of brevity. When the thicker second light emitting structure 1109b contacts the second spacer 1104b, the bonding process is stopped. At this time, the thickness of the first bonding material 1105a is greater than the thickness of the second bonding material 1105b, the thickness of the first spacer 1104a is less than the sum of the thicknesses of the first conductive pad 1103a, the first bonding material 1105a, and the second conductive pad 1107a, and the thickness of the second spacer 1104b is equal to the sum of the thicknesses of the third conductive pad 1103b, the second bonding material 1105b, and the fourth conductive pad 1107 b. In addition, after the bonding process is performed, the tab 1111 is removed to form the display device 1100.

The display device 1100 can easily dispose the first and

second bonding materials

1105a and 1105b by disposing the coating paste 1113, and reduce the number of overall manufacturing process steps, compared to the

display devices

700, 800, 900, and 1000.

Fig. 12A-12E are cross-sectional schematic diagrams illustrating intermediate stages in forming a display device 1200 according to some embodiments of the invention. Fig. 12A-12E have elements similar to those of fig. 11A-11E and will not be repeated here for simplicity of description.

In some embodiments, as shown in fig. 12A, a plurality of first conductive pads 1203a and a plurality of third conductive pads 1203b are formed on the substrate 1201. The materials and fabrication processes of the first and third

conductive pads

1203a, 1203b may be similar or identical to those of the first and third

conductive pads

303a, 303b of the display device 300, and are not repeated here for brevity.

Subsequently, as shown in fig. 12B, similar to fig. 11B, a coating adhesive 1213 is formed on the first and third conductive pads 1203a, 1203B. In some embodiments, the process and material for making the coating paste 1213 may be similar or identical to the process and material for making the coating paste 1113 in fig. 11B, and are not repeated here.

Next, as shown in fig. 12C, similarly to fig. 11C, the first and

second bonding materials

1205a, 1205b are provided on the coating paste 1213, and a part of the first and

second bonding materials

1205a, 1205b is embedded in the coating paste 1113. In some embodiments, the process and materials for forming first and

second bonding materials

1205a, 1205b may be similar or identical to the process and materials for forming first and

second bonding materials

1105a, 1105b of fig. 11C and are not repeated here.

As shown in fig. 12D, similar to fig. 11D, the first light emitting structure 1209a and the second light emitting structure 1209b are adsorbed or adhered by the joint 1211, and the thickness of the first light emitting structure 1209a is smaller than that of the second light emitting structure 1209 b. A plurality of second conductive pads 1207a are formed on the bottom surface of the first light emitting structure 1209a, and a plurality of fourth conductive pads 1209b are formed on the bottom surface of the second light emitting structure 1209 b. The fabrication process and materials of the first and second

light emitting structures

1209a and 1209b may be similar to or the same as the first and second

light emitting structures

conductive pads

1207a and 1207b may be similar to or the same as the second and fourth

conductive pads

Fig. 12D differs from fig. 11D in the location of the first and

second spacers

1204a, 1204 b. As shown in fig. 12D, first and

second spacers

1204a, 1204b are disposed on the first and second

light emitting structures

1209a, 1209b, respectively. Notably, the thickness of the first and

second spacers

1204a, 1204b is less than the thickness of the first and

second bonding materials

1205a, 1205 b.

Subsequently, as shown in fig. 12E, a bonding process is performed to simultaneously bond the first and second

light emitting structures

1209a, 1209b to the substrate 1201 through the joint 1211, so as to form the display device 1200 below the joint 1211. The temperature and pressure applied by the joint 1211 are the same as those applied by the joint 311 of fig. 3B, and are not repeated here for the sake of brevity. The bonding process stops when the second spacers 1204b on the thicker second light emitting structures 1209b contact the substrate 1201. At this time, the thickness of the first bonding material 1205a is greater than that of the second bonding material 1205b, the thickness of the first spacer 1204a is less than the sum of the thicknesses of the first conductive pad 1203a, the first bonding material 1205a and the second conductive pad 1207a, and the thickness of the second spacer 1204b is equal to the sum of the thicknesses of the third conductive pad 1203b, the second bonding material 1205b and the fourth conductive pad 1207 b. In addition, after the bonding process is performed, the joint 1211 is removed to form the display device 1200.

Similar to the display device 1100, the display device 1200 can easily dispose the first and

second bonding materials

1205a, 1205b by disposing the coating paste 1213, and reduce the overall manufacturing process steps.

Fig. 13A-13E are cross-sectional views illustrating intermediate stages in forming a display device 1300, according to some embodiments of the invention.

According to some embodiments, as shown in fig. 13A, a plurality of first conductive pads 1303A and a plurality of third conductive pads 1303b are formed on a substrate 1301. The materials and fabrication processes of the first and third

conductive pads

1303a and 1303b may be similar or identical to those of the first and third

conductive pads

303a and 303b of the display device 300, and are not repeated here for brevity.

Subsequently, as shown in fig. 13B, a coating paste 1313 including the spacers 1304 is formed on the substrate 1301, the first pad 1303a, and the third pad 1303B. The process and materials for making the coating paste 1313 and the spacers 1304 may be similar or identical to the coating paste 1113 and the first and second spacers 1104a and 1104B shown in fig. 11B, and are not repeated here for the sake of brevity. In some embodiments, after the coating 1313 including the spacers 1304 is formed, the spacers 1304 located above the first conductive pads 1303a are first spacers 1304a, and the spacers 1304 located above the second conductive pads 1303b are second spacers 1304 b. In addition, the content of the spacers 1304 in the coating 1313 and the viscosity of the coating 1313 can be adjusted according to the requirements of the manufacturing process.

Next, as shown in fig. 13C, first and

second bonding materials

1305a, 1305b are provided on the coating paste 1313, and a part of the first and

second bonding materials

1305a, 1305b is embedded in the coating paste 1313. Notably, the thickness of first and

second bonding materials

1305a, 1305b is greater than the thickness of spacers 1304. In some embodiments, the processes and materials for forming first and

second bonding materials

1305a, 1305b may be similar or identical to the processes and materials for forming first and

second bonding materials

1105a, 1105b of fig. 11C, and are not repeated here.

As shown in fig. 13D, the first light emitting structure 1309a and the second light emitting structure 1309b are adsorbed or adhered by the joint 1311, and the thickness of the first light emitting structure 1309a is smaller than that of the second light emitting structure 1309 b. A plurality of second conductive pads 1307a are formed on the bottom surface of the first light emitting structure 1309a, and a plurality of fourth conductive pads 1309b are formed on the bottom surface of the second light emitting structure 1309 b. The fabrication process and materials of the first and second

light emitting structures

1309a, 1309b can be similar or identical to the first and second

light emitting structures

309a, 309b of the display device 300, and the fabrication process and materials of the second and fourth

conductive pads

1307a, 1307b can be similar or identical to the second and fourth

conductive pads

307a, 307b of the light emitting structure 300, which will not be repeated here for brevity of description.

According to some embodiments, as shown in fig. 13E, a bonding fabrication process is performed to simultaneously bond the first and second

light emitting structures

1309a, 1309b to the substrate 1301 through the joints 1311 to form the display device 1300 below the joints 1311. The temperature and pressure applied to the joint 1311 are the same as those applied to the joint 311 of fig. 3B, and will not be described here for the sake of brevity. The bonding process stops when the fourth conductive pad 1307b on the thicker second light emitting structure 1309b contacts the second spacer 1304b on the second conductive pad 1303 b. At this time, the thickness of first bonding material 1305a is greater than the thickness of second bonding material 1305b, the thickness of first spacer 1304a is less than the thickness of first bonding material 1305a, and the thickness of second spacer 1304b is equal to the thickness of second bonding material 1105 b. Further, after the bonding fabrication process is performed, the joints 1311 are removed to form the display device 1300.

Similar to the

display devices

1100 and 1200, the display device 1300 can easily dispose the first spacers 1304a, the second spacers 1304b, the first bonding material 1305a, and the second bonding material 1305b by disposing the coating paste 1313, and can reduce the overall manufacturing process steps.

In order to solve the problem that the light emitting structure and the substrate cannot be smoothly bonded due to the thickness difference of the light emitting structure or the conductive pad in the manufacturing process of eutectic bonding, in the embodiment of the invention, the cross section of the bonding material is reduced or the bonding material is patterned, so that the accommodating space is generated between the substrate and the conductive pad on the light emitting structure, and excessive bonding material generated by extrusion enters the accommodating space, thereby avoiding the problem of short circuit between the conductive pads.

In addition, the embodiments of the invention ensure that the distance from the surface of each light emitting structure far from the substrate to the substrate is consistent when the bonding process is stopped by arranging the plurality of spacers with equal height between the substrate and the light emitting structure, and on the other hand, by arranging the spacers between the adjacent conductive pads on the substrate or the light emitting structure, the short circuit between the two adjacent conductive pads on the substrate or the light emitting structure after the bonding process can be avoided.

The components of several embodiments are summarized above so that those skilled in the art to which the present invention pertains can more understand the aspects of the embodiments of the present invention. Those skilled in the art should appreciate that they may readily use the present disclosure 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.

Claims

1. A display device, comprising:

the first conductive pad is arranged on a substrate, wherein a contact area is formed between the first conductive pad and the substrate;

a first bonding material disposed on the first conductive pad, wherein the first bonding material has a gap or a hole therein, and wherein the first bonding material has a cross-sectional area in a direction parallel to the substrate surface;

a second conductive pad disposed on the first bonding material; and

a first light emitting structure disposed on the second conductive pad,

wherein the cross-sectional area of the first bonding material is smaller than the contact area of the first conductive pad.

2. The display device according to claim 1, wherein the cross-sectional area is located within a range of 15% of the thickness of the first bonding material above and below the center of the first bonding material.

3. The display device of claim 1, wherein the first bonding material has an inwardly recessed cross-sectional profile.

4. The display device of claim 1, further comprising:

a third conductive pad disposed on the substrate;

a second bonding material disposed on the third conductive pad, wherein the second bonding material has an outwardly protruding cross-sectional profile;

a fourth conductive pad disposed on the second bonding material; and

and the second light-emitting structure is arranged on the fourth conductive pad.

5. The display device of claim 4, wherein the first bonding material thickness is greater than the second bonding material thickness.

6. The display device according to claim 4, wherein a thickness of the first light emitting structure is smaller than a thickness of the second light emitting structure.

7. The display device of claim 4, wherein the second bonding material has a gap or hole therein.

8. A display device, comprising:

the first conductive pad is arranged on a substrate;

a first bonding material disposed on the first conductive pad;

a second conductive pad disposed on the first bonding material;

the first light-emitting structure is arranged on the second conductive pad;

a first spacer disposed between the substrate and the first light emitting structure; and

the coating glue is arranged between the substrate and the first light-emitting structure, wherein the first bonding material is arranged in the coating glue and is spherical;

the first spacer is spherical, disposed in the coating glue, and contacts the first conductive pad and the second conductive pad.

9. The display device of claim 8, wherein the first spacer contacts the substrate or the first light emitting structure, and a thickness of the first spacer is less than a sum of thicknesses of the first conductive pad, the first bonding material, and the second conductive pad.

10. The display device of claim 8, wherein a portion of the first spacer extends between the first conductive pad and the second conductive pad, the portion of the first spacer contacts the first conductive pad or the second conductive pad, and the thickness of the portion is less than the thickness of the first bonding material.

11. The display device of claim 8, further comprising:

a third conductive pad disposed on the substrate;

a second bonding material disposed on the third conductive pad, wherein the thickness of the first bonding material is greater than the thickness of the second bonding material;

a fourth conductive pad disposed on the second bonding material;

the second light-emitting structure is arranged on the fourth conductive pad; and

and the second gap object is arranged between the substrate and the second light-emitting structure.

12. The display apparatus of claim 11, wherein two ends of the second spacer respectively contact the substrate and the second light emitting structure, and a thickness of the second spacer is equal to a sum of thicknesses of the third conductive pad, the second bonding material and the fourth conductive pad.

13. The display device of claim 11, wherein a portion of the second spacer extends between the third conductive pad and the fourth conductive pad, the second spacer contacts the substrate or the second light emitting structure, and two ends of the portion of the second spacer contact the third conductive pad and the fourth conductive pad, respectively.

14. A method of forming a display device, comprising:

forming a first conductive pad on a substrate, wherein a contact area is formed between the first conductive pad and the substrate;

forming a second conductive pad on a first light emitting structure;

forming a first bonding material on the first conductive pad, wherein the first bonding material has a cross-sectional area in a direction parallel to the substrate surface, and the cross-sectional area of the first bonding material is smaller than the contact area of the first conductive pad;

implementing a bonding process to bond the first light-emitting structure to the substrate;

before the bonding manufacture process is carried out, a first gap object is formed on the substrate or the first light-emitting structure, and the thickness of the first bonding material is larger than that of the first gap object; and

after the bonding process is performed, one end of the first spacer contacts the substrate, and the other end of the first spacer contacts the first light emitting structure.

15. A method of forming a display device, comprising:

forming a first conductive pad on a substrate;

forming a second conductive pad on a light emitting structure;

forming a spacer on the substrate or the light-emitting structure;

forming a coating adhesive on the substrate and the first conductive pad;

forming a bonding material on the coating glue, and embedding the bonding material into the coating glue, wherein the thickness of the bonding material is greater than that of the spacer; and

and implementing a bonding process to bond the light-emitting structure to the substrate.

16. A method of forming a display device, comprising:

forming a first conductive pad on a substrate;

forming a second conductive pad on a light emitting structure;

forming a coating adhesive on the substrate and the first conductive pad, or forming the coating adhesive on the light-emitting structure and the second conductive pad, wherein a spacer is arranged in the coating adhesive;