CN113964248A

CN113964248A - Display device and method for manufacturing the same

Info

Publication number: CN113964248A
Application number: CN202111191246.8A
Authority: CN
Inventors: 刘仲展
Original assignee: AU Optronics Corp
Current assignee: AU Optronics Corp
Priority date: 2021-04-01
Filing date: 2021-10-13
Publication date: 2022-01-21
Anticipated expiration: 2041-10-13
Also published as: TW202240248A; CN113964248B; TWI757141B

Abstract

The invention discloses a display device and a manufacturing method thereof, wherein the display device comprises a circuit substrate and a light-emitting element. The light-emitting element is electrically connected with the circuit substrate and is provided with an opening, wherein the opening is positioned at one side of the light-emitting element close to or far away from the circuit substrate.

Description

Display device and method for manufacturing the same

Technical Field

The present invention relates to a display device and a method for manufacturing the same, and more particularly, to a micro light emitting diode display device and a method for manufacturing the same.

Background

Because the size of the micro light emitting diode is extremely small, the current method for manufacturing the micro light emitting diode display device adopts a Mass Transfer (Mass Transfer) technology, that is, a micro electro mechanical array technology is utilized to pick and place the micro light emitting diode bare chip, so that a large number of micro light emitting diode bare chips are transported to a driving substrate with a pixel circuit at one time. There are various new mass transfer techniques that are continuously being published, among which laser transfer techniques are favored because of their efficiency advantages.

The laser transfer technology realizes the separation of the bare chip by the light-matter reaction of the laser and the connecting material, and simultaneously, the generated impact force or driving force can separate the bare chip and push the bare chip to transfer towards a target substrate. However, when the photo-material reaction occurs, the direction of die detachment is not fixed due to the impact force or uneven distribution of driving force, and the die cannot be accurately transferred to the target substrate.

Disclosure of Invention

The invention provides a display device having light emitting elements with accurate transfer.

The invention provides a method for manufacturing a display device, which can accurately transfer a light emitting element.

One embodiment of the present invention provides a display device including: a circuit substrate; and the light-emitting element is electrically connected with the circuit substrate and is provided with an opening, wherein the opening is positioned at one side of the light-emitting element close to or far away from the circuit substrate.

In an embodiment of the invention, an orthographic projection of the opening on the circuit substrate is overlapped with an orthographic projection of a center of gravity of the light emitting element on the circuit substrate.

In an embodiment of the invention, the light emitting device includes two electrodes, and the opening is at least partially located outside the two electrodes.

In an embodiment of the invention, the light emitting device includes two electrodes, and the opening is located between the two electrodes.

In an embodiment of the invention, the opening is located on a light emitting surface or a non-light emitting surface of the light emitting element.

In an embodiment of the invention, the opening penetrates through the light emitting element.

In an embodiment of the invention, a cross section of the opening has a regular trapezoid or an inverted trapezoid.

In an embodiment of the invention, the opening has a lateral blind hole therein.

In an embodiment of the invention, an aperture of the opening is smaller than 1/3 of the width of the light emitting element.

In an embodiment of the invention, a diameter of the opening is less than or equal to 3 μm.

In an embodiment of the invention, a depth of the opening is greater than or equal to 1 μm.

In an embodiment of the invention, the circuit substrate includes an active device array.

In an embodiment of the invention, the display device further includes a connection column, and the connection column is at least partially located in the opening.

In an embodiment of the invention, the connection pillar includes a plurality of layers, and the plurality of layers have different concentrations, light absorption rates or light transmittance rates.

One embodiment of the present invention provides a method of manufacturing a display device, including: providing a light-emitting element, wherein the light-emitting element is positioned on the first carrier plate; forming an opening on the surface of the light-emitting element far away from the first carrier plate; forming a connecting layer on the surface, and filling the connecting layer into the opening; fixing the second carrier plate on the connecting layer, so that the light-emitting element is positioned between the first carrier plate and the second carrier plate; removing the first carrier plate; removing the connecting layer, and reserving the connecting layer between the opening and the second carrier plate to form a connecting column; providing a third carrier plate, and aligning the light-emitting element with the third carrier plate, wherein the light-emitting element is positioned between the second carrier plate and the third carrier plate; and focusing the laser beam on the connecting column to separate the light-emitting element from the second carrier plate, so that the light-emitting element is transferred onto the third carrier plate.

In an embodiment of the invention, an orthographic projection of the opening on the surface is overlapped with an orthographic projection of a center of gravity of the light emitting element on the surface.

In an embodiment of the invention, the third carrier is a circuit substrate.

In an embodiment of the invention, the connection layer includes a plurality of layers, and the plurality of layers have different concentrations, light absorption rates or light transmittance rates.

Drawings

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

Fig. 1A to 1I are schematic cross-sectional views illustrating a process flow of a method for manufacturing a display device 10 according to an embodiment of the invention.

Fig. 2A to fig. 2G are schematic cross-sectional views illustrating a process flow of a method for manufacturing the display device 20 according to an embodiment of the invention.

Fig. 3A to fig. 3H are schematic cross-sectional views illustrating a process flow of a method for manufacturing a display device 30 according to an embodiment of the invention.

Fig. 4A to 4G are schematic cross-sectional views illustrating a process flow of a method for manufacturing a display device 40 according to an embodiment of the invention.

Description of the symbols

10. 20, 30, 40: display device

110: source substrate

120. 220, 320, 420: light emitting element

121. 321, 421: first type semiconductor layer

121a, 321a, 421 a: electrode for electrochemical cell

121 b: connecting pad

121c, 421 c: connecting wire

121S: surface of

122. 322, 422: second type semiconductor layer

122a, 322a, 422 a: electrode for electrochemical cell

122 b: connecting pad

122 c: connecting wire

123. 323, 423: luminescent layer

130. 330, 340: adhesive layer

150. 350 and 450: connecting layer

150a, 350a, 450 a: connecting column

170: circuit board

170a, 170 b: connecting pad

171: base plate

172: element layer

180: laser device

351. 351a, 451 a: first layer

352. 352a, 452 a: second layer

353. 353a, 453 a: third layer

454. 454 a: the fourth layer

B1, B2, B3, B4: lateral blind hole

BP: bottom part

C1, C2, C3, C4, C5, C6, C7: support plate

D1: distance between each other

Da: bore diameter

And Dt: depth of field

IS: insulating layer

LB: laser beam

NP: neck part

O1, O2, O3, O4: opening of the container

T: active (active) element

W: width of

Detailed Description

Fig. 1A to 1I are schematic cross-sectional views illustrating a process flow of a method for manufacturing a display device 10 according to an embodiment of the invention. First, referring to fig. 1A, a light emitting device 120 grown on a source substrate 110 is provided, the light emitting device 120 includes a first type semiconductor layer 121, a second type semiconductor layer 122, a light emitting layer 123 located between the first type semiconductor layer 121 and the second type semiconductor layer 122, and a plurality of electrodes 121A and 122a electrically connected to the first type semiconductor layer 121 and the second type semiconductor layer 122, respectively. In the present embodiment, the plurality of

electrodes

121a and 122a are located on the same side of the first-type semiconductor layer 121. That is, the light emitting diode element 120 is a horizontal (lareral) micro light emitting diode.

In the embodiment, the method may further include forming

pads

121b and 122b on the

electrodes

121a and 122a, respectively, wherein the pad 121b is electrically connected to the electrode 121a, the pad 122b is electrically connected to the electrode 122a, and a top surface of the pad 121b is aligned with a top surface of the pad 122b, but not limited thereto. The material of the

pads

121b and 122b is metal, but the invention is not limited thereto. In other embodiments, the

pads

121b and 122b may also be made of other conductive materials, such as: alloys, nitrides of metallic materials, oxides of metallic materials, oxynitrides of metallic materials, graphene, stacked layers of metallic materials, or stacked layers of other conductive materials.

Next, referring to fig. 1B, a carrier C1 coated with an adhesive layer 130 is provided, and the light emitting device 120 is attached to the adhesive layer 130, wherein the light emitting device 120 is located between the source substrate 110 and the carrier C1. Subsequently, the source substrate 110 is removed to expose the surface 121S of the first type semiconductor layer 121 away from the carrier C1. The source substrate 110 may be removed by, for example, a Laser Lift Off (Laser Lift Off) process, but the invention is not limited thereto.

Next, referring to fig. 1C, an opening O1 is formed on the surface 121S of the first-type semiconductor layer 121. In the present embodiment, the opening O1 may be completely located in the first type semiconductor layer 121 and may be located on the light emitting surface of the light emitting element 120. In addition, the orthographic projection of the opening O1 on the surface 121S may overlap the orthographic projection of the center of gravity of the light emitting element 120 on the surface 121S, but the invention is not limited thereto. In the present embodiment, the cross section of the opening O1 may be a regular trapezoid with a narrow top and a wide bottom, but the present invention is not limited thereto. In some embodiments, the opening O1 may also extend down to penetrate the first-type semiconductor layer 121 or deeper. The opening O1 may be formed by a photolithographic etching process. For example, in the present embodiment, the opening O1 with a regular trapezoid cross section can be formed by a dry etching process in combination with a wet etching process.

Next, referring to fig. 1D, a connection layer 150 is formed on the light emitting element 120 and the adhesive layer 130, and the connection layer 150 fills the opening O1. The material of the connecting layer 150 is a material that can be decomposed (e.g., ablated) by reaction with the laser. In the embodiment, the connection layer 150 may have an adhesive property, but the invention is not limited thereto. In some embodiments, when the connecting layer 150 is not adhesive, an adhesive layer may be formed on the connecting layer 150.

Next, referring to fig. 1E, a carrier C2 is attached on the connection layer 150, and the light emitting device 120 is located between the carrier C1 and the carrier C2. Carrier C1 is then removed. The carrier plate C1 can be removed by heating, for example, but the invention is not limited thereto.

Next, referring to fig. 1F, the adhesive layer 130 is removed to expose the

pads

121b and 122 b. The adhesion layer 130 may be removed by a wet etching process, but the invention is not limited thereto.

Next, referring to fig. 1G, most of the connection layer 150 is removed, but a portion of the connection layer 150 between the opening O1 and the carrier C2 remains, so as to form a connection post 150a, and the connection post 150a is at least partially located in the opening O1. The connection layer 150 may be removed by a wet etching process, but the invention is not limited thereto.

Next, referring to fig. 1H, a circuit substrate 170 is provided, and the circuit substrate 170 may include a plurality of

pads

170a and 170b, and the light emitting device 120 is aligned with the circuit substrate 170, such that the light emitting device 120 is located between the carrier C2 and the circuit substrate 170. Specifically, in the embodiment, the alignment step aligns the

pads

121b and 122b of the light emitting device 120 with the

pads

170a and 170b of the circuit board 170, respectively, but the invention is not limited thereto, and other suitable alignment methods may be adopted.

Thereafter, the laser beam LB from the laser 180 is focused on the connecting post 150 a. Specifically, the connecting post 150a may include a neck NP located outside the opening O1 and a bottom BP located inside the opening O1. In the present embodiment, the laser beam LB may be focused on the neck NP of the connecting pillar 150a, so that the neck NP of the connecting pillar 150a reacts with the laser beam LB to be decomposed, and the bottom BP of the connecting pillar 150a may remain in the opening O1. When the neck portion NP of the connection post 150a is broken due to decomposition, the light emitting device 120 can drop vertically toward the right lower side in a free-fall manner, and accurately transfer to the circuit substrate 170, so that the

pads

121b and 122b can contact the

pads

170a and 170b, respectively, as shown in fig. 1I. At this time, in the formed display device 10, the

electrodes

121a, 122a of the light emitting element 120 may be positioned between the first type semiconductor layer 121 and the circuit substrate 170.

In some embodiments, the laser beam LB may be focused on the bottom BP of the connecting column 150a such that the bottom BP of the connecting column 150a reacts with the laser beam LB to generate an impact force or driving force. In detail, the lateral impact or driving force generated by the reaction of the bottom BP of the connecting column 150a and the laser beam LB can be offset by acting on the sidewall of the opening O1, so that the net impact or driving force is a resultant force in the longitudinal direction. The downward force can make the light emitting device 120 move forward to the right below and accurately transfer to the circuit substrate 170, so that the

pads

121b and 122b can be respectively connected to the

pads

170a and 170 b.

In some embodiments, the steps further include electrically connecting the pad 121b of the light emitting device 120 and the pad 170a of the circuit substrate 170, and electrically connecting the pad 122b of the light emitting device 120 and the pad 170b of the circuit substrate 170. The method of electrically connecting the

pads

121b and 170a and the

pads

122b and 170b may use eutectic bonding or other similar methods, but the invention is not limited thereto.

Referring to fig. 1I, in the present embodiment, the display device 10 includes a circuit substrate 170 and a light emitting element 120. The light emitting device 120 is electrically connected to the circuit substrate 170 and has an opening O1, and the opening O1 is located on a side of the light emitting device 120 away from the circuit substrate 170. The range of action of the laser beam during the laser transfer process is adjusted by the opening O1 of the light emitting device 120, so that the light emitting device 120 can be accurately transferred onto the circuit substrate 170, and the display device 10 has an array of light emitting devices 120 with accurate mass transfer.

In some embodiments, the circuit substrate 170 may include a bottom plate 171, a device layer 172, and a plurality of

pads

170a and 170 b. The element layer 172 including an array of active elements T (e.g., a thin film transistor array) may be formed on the base plate 171 using a thin film deposition fabrication process, a photomask fabrication process, and an etching fabrication process. After the element layer 172 is formed, a plurality of

electrodes

170a and 170b may be formed on the element layer 172 by continuing a thin film deposition process, a photomask process, and an etching process.

The position of the opening O1 on the light emitting element 120 is not particularly limited. In the display device 10, the orthographic projection of the opening O1 on the circuit board 170 may be overlapped with the orthographic projection of the center of gravity of the light emitting element 120 on the circuit board 170, but the invention is not limited thereto. Specifically, the position of the center of gravity of the light-emitting element 120 can be obtained by calculating the area and density distribution of each layer of the light-emitting element 120. The orthographic projection of the opening O1 on the circuit substrate 170 is overlapped with the orthographic projection of the center of gravity of the light-emitting element 120 on the circuit substrate 170, so that the light-emitting element 120 can be kept in a desired balance when the light-emitting element 120 is suspended on the carrier C2 through the connecting column 150a, as shown in fig. 1H.

The shape of the opening O1 is not particularly limited. In the present embodiment, the cross section of the opening O1 has a regular trapezoid shape with a narrow top and a wide bottom, but the invention is not limited thereto. In some embodiments, the cross section of the opening O1 may also have an inverted trapezoid shape with a wide top and a narrow bottom. In other embodiments, the cross-section of the opening O1 may have a burred profile by further forming a lateral blind hole in the opening O1.

The size of the opening O1 may be as small as possible so as not to affect the optical and electrical properties of the light emitting element 120, but the invention is not limited thereto. In the present embodiment, the aperture Da of the opening O1 may be smaller than 1/3 of the width W of the light emitting element 120, i.e., Da < 1/3W. In some embodiments, the aperture Da of the opening O1 may be less than or equal to 3 μm, for example, the aperture Da is 3 μm, 2 μm or 1.5 μm, and an appropriate aperture Da may be selected as required.

The opening O1 may have a sufficient depth to, for example, ensure that the net impact or driving force generated by the connection post 150a reacting with the laser beam LB is a downward force. In some embodiments, the depth Dt of the opening O1 may be greater than or equal to 1 μm, for example, the depth Dt is greater than or equal to 1 μm, 2 μm, or 3 μm, but the invention is not limited thereto. In some embodiments, a portion of the connecting post 150a may remain in the opening O1.

Fig. 2A to fig. 2G are schematic cross-sectional views illustrating a process flow of a method for manufacturing the display device 20 according to an embodiment of the invention. The following reference numerals and related contents along the embodiments of fig. 1A to 1I are used, wherein the same reference numerals are used to denote the same or similar elements, and the description of the same technical contents is omitted. For the description of the omitted portions, reference may be made to the embodiments of fig. 1A to 1I, and the description will not be repeated.

First, referring to fig. 2A, a light emitting device 220 grown on a source substrate 110 is provided, wherein the light emitting device 220 includes a first type semiconductor layer 121, a second type semiconductor layer 122, a light emitting layer 123 located between the first type semiconductor layer 121 and the second type semiconductor layer 122, and a plurality of electrodes 121a and 122A electrically connected to the first type semiconductor layer 121 and the second type semiconductor layer 122, respectively.

Next, referring to fig. 2B, an opening O2 is formed in the electrode 122a and the second-type semiconductor layer 122. In the embodiment, the opening O2 is located in the electrode 122a and the second-type semiconductor layer 122, but the invention is not limited thereto. In some embodiments, the opening O2 may also penetrate through the light emitting layer 123 and extend to the first-type semiconductor layer 121.

In the embodiment, at least 2 lateral blind holes may be further formed in the opening O2, so that the opening O2 has a thorn-like shape, thereby improving the supporting force of the connection post 150a subsequently formed in the opening O2, and further improving the stability of the connection post 150a suspending the light emitting device 220. For example, the lateral blind holes B1, B2, B3, B4 may be formed in the opening O2, but the invention is not limited thereto.

Forming the barbed opening O2 may be accomplished using a multi-pass etching process. For example, in the present embodiment, the main portion of the opening O2 may be formed by first performing two etching processes, wherein the two etching processes use an etchant capable of selectively etching the electrode 122a and the second-type semiconductor layer 122, respectively. Thereafter, the lateral blind holes B1, B2 may be formed using an etchant having selectivity to the specific lattice orientation of the electrode 122a, and then the lateral blind holes B3, B4 may be formed using an etchant having selectivity to the specific lattice orientation of the second-type semiconductor layer 122. In other embodiments, the etchant selective to a specific material may be selected to form the openings O2 with various shapes according to actual requirements.

Next, referring to fig. 2C, a connection layer 150 is formed on the light emitting device 220 and the source substrate 110, and the connection layer 150 fills the opening O2.

Next, referring to fig. 2D, a carrier C3 is attached on the connection layer 150, the light emitting device 220 is located between the source substrate 110 and the carrier C3, and then the source substrate 110 is removed. The source substrate 110 may be removed by, for example, laser lift-off, but the invention is not limited thereto.

Next, referring to fig. 2E, most of the connection layer 150 is removed, but a portion of the connection layer 150 between the opening O2 and the carrier C3 remains, so as to form a connection post 150a, and the connection post 150a fills the opening O2 and has a cross-sectional shape of a thorn. Thus, the connecting posts 150a with bristles have a supporting force to stably suspend the light emitting device 220. In the present embodiment, the connection layer 150 may be removed by, for example, a wet etching process, but the invention is not limited thereto.

Next, referring to fig. 2F, a circuit substrate 170 is provided, and the circuit substrate 170 may include a plurality of

pads

170a and 170b on a surface thereof. The light emitting device 220 and the circuit substrate 170 are aligned, such that the light emitting device 220 is located between the carrier C3 and the circuit substrate 170, and the orthographic projection of the light emitting device 220 on the circuit substrate 170 is located between the

pads

170a and 170b of the circuit substrate 170. Then, the laser beam LB emitted from the laser 180 is focused on the bottom BP of the connection post 150a, so that the light emitting element 220 is accurately transferred onto the circuit substrate 170 by moving right downward.

Next, referring to fig. 2G, connecting

wires

121c and 122c are formed, wherein the connecting wire 121c connects the electrode 121a of the light emitting device 220 and the pad 170a of the circuit substrate 170, and the connecting wire 122c connects the electrode 122a of the light emitting device 220 and the pad 170b of the circuit substrate 170, so as to complete the display device 20 of the embodiment.

The display device 20 shown in fig. 2G differs from the display device 10 shown in fig. 1I in that: in the display device 20, the opening O2 has a burred shape and is located on the non-light-emitting surface of the light-emitting element 220, the first type semiconductor layer 121 of the light-emitting element 220 is located between the

electrodes

121a and 122a and the circuit substrate 170, and the

electrodes

121a and 122a of the light-emitting element 220 are connected to the

pads

170a and 170b of the circuit substrate 170 through the connecting

wires

121c and 122c, respectively.

Fig. 3A to fig. 3H are schematic cross-sectional views illustrating a process flow of a method for manufacturing a display device 30 according to an embodiment of the invention. The following reference numerals and related contents along the embodiments of fig. 1A to 1I are used, wherein the same reference numerals are used to denote the same or similar elements, and the description of the same technical contents is omitted. For the description of the omitted portions, reference may be made to the embodiments of fig. 1A to 1I, and the description will not be repeated.

First, referring to fig. 3A, a light emitting device 320 grown on a source substrate 110 is provided, the light emitting device 320 includes a first type semiconductor layer 321, a second type semiconductor layer 322, a light emitting layer 323 located between the first type semiconductor layer 321 and the second type semiconductor layer 322, and a plurality of

electrodes

321a and 322a electrically connected to the first type semiconductor layer 321 and the second type semiconductor layer 322, respectively. In the present embodiment, the light emitting diode element 320 may be a Flip-chip micro light emitting diode.

Next, referring to fig. 3B, a carrier C4 coated with an adhesive layer 330 is provided, and the first type semiconductor layer 321 of the light emitting device 320 is attached to the adhesive layer 330, wherein the light emitting device 320 can be located between the source substrate 110 and the carrier C4. Subsequently, the source substrate 110 is removed to expose the

electrodes

321a and 322a of the light emitting element 320, and the

electrodes

321a and 322a have the opening O3 therebetween. The source substrate 110 may be removed by, for example, a Laser Lift Off (Laser Lift Off) process, but the invention is not limited thereto.

Next, referring to fig. 3C, a connection layer 350 is formed on the light emitting element 320 and the adhesive layer 330, and the connection layer 350 fills the opening O3 between the

electrodes

321a and 322 a. In this embodiment, the connection layer 350 may include a plurality of layers. For example, the connection layer 350 may include a first layer 351, a second layer 352 and a third layer 353, wherein the second layer 352 is located between the first layer 351 and the third layer 353, but the invention is not limited thereto. In the present embodiment, the first layer 351, the second layer 352, and the third layer 353 may have sequentially increasing light transmittance with respect to the subsequently used laser beam LB. In some embodiments, first layer 351, second layer 352, and third layer 353 may have sequentially decreasing light transmittance relative to subsequently used laser beam LB. In some embodiments, first layer 351, second layer 352, and third layer 353 may have increasing and decreasing optical absorption relative to subsequently used laser beam LB. In some embodiments, first layer 351, second layer 352, and third layer 353 may have a decreasing and then increasing optical absorption relative to subsequently used laser beam LB. In some embodiments, the first layer 351, the second layer 352 and the third layer 353 may also include laser absorbing material, and the concentration of the laser absorbing material in the first layer 351, the second layer 352 and the third layer 353 may increase sequentially, decrease sequentially or increase sequentially.

The material of the connection layer 350 is a material that can be decomposed by reaction with laser light. The connection layer 350 may have an adhesive property, but the present invention is not limited thereto. In some embodiments, when the third layer 353 of the connecting layer 350 is not adhesive, an adhesive layer may be formed on the third layer 353.

Next, referring to fig. 3D, a carrier C5 is attached on the connection layer 350, the light emitting device 320 is located between the carrier C5 and the carrier C4, and then the carrier C4 is removed. In some embodiments, the adhesive layer 330 may be removed simultaneously with the removal of the carrier C4. The carrier C4 and the adhesive layer 330 can be removed by heating, for example, but the invention is not limited thereto.

Next, referring to fig. 3E, most of the connection layer 350 is removed, but a portion of the connection layer 350 between the opening O3 and the carrier C5 remains, so as to form a connection post 350a, wherein the connection post 350a includes a first layer 351a, a second layer 352a and a third layer 353a, and the connection post 350a is at least partially located in the opening O3. In the present embodiment, the first layer 351a, the second layer 352a and the third layer 353a may have sequentially increasing light transmittance with respect to the laser beam LB.

In some embodiments, the first layer 351a, the second layer 352a and the third layer 353a may have sequentially decreasing light transmittance with respect to the laser beam LB. In some embodiments, first layer 351a, second layer 352a, and third layer 353a may have increasing and decreasing optical absorption relative to laser beam LB. In some embodiments, first layer 351a, second layer 352a, and third layer 353a may have decreasing and then increasing optical absorption relative to laser beam LB. In some embodiments, the first layer 351a, the second layer 352a and the third layer 353a may also include laser absorbing material, and the concentration of the laser absorbing material in the first layer 351a, the second layer 352a and the third layer 353a may increase sequentially, decrease sequentially or increase sequentially. The breaking position of the connection post 350a after reacting with the laser beam LB can be adjusted by the increasing or decreasing light transmittance, light absorptivity, or laser absorbing material concentration, so as to optimize the mass transfer of the light emitting device 320.

In some embodiments, when the light emitting device 320 is viewed from the carrier C5 in a direction of the light emitting device 320 in a top view, the distance D1 between the

electrodes

321a and 322a may be smaller than the length of the

electrodes

321a and 322a in a direction perpendicular to the distance D1, and at this time, the opening O3 may be a long groove between the

electrodes

321a and 322a, so that the connection pillar 350a has an elongated top view shape, in which case, the connection pillar 350a in the middle of the opening O3 may be remained, and the connection pillar 350a in the rest of the opening O3 may be completely removed, so that the connection pillar 350a has an approximately cylindrical shape.

Next, referring to fig. 3F, a carrier C6 is provided, an adhesive layer 340 is coated on one surface of the carrier C6, and the light emitting device 320 is disposed above the adhesive layer 340, such that the light emitting device 320 is located between the carrier C6 and the carrier C5. Then, the laser beam LB emitted from the laser 180 is focused on the first layer 351a of the connection pillar 350a, so that the first layer 351a of the connection pillar 350a reacts with the laser beam LB to generate a net impact or driving force in a downward direction, and the light emitting element 320 moves forward to the carrier C6, as shown in fig. 3G. In the embodiment, since the third layer 353a and the second layer 352a have higher light transmittance than the first layer 351a, a relatively large portion of the laser beam LB can penetrate through the third layer 353a and the second layer 352a to reach the first layer 351a, thereby improving the light utilization rate of the laser beam LB acting on the first layer 351 a.

Next, referring to fig. 3H, a circuit substrate 170 is provided, and the circuit substrate 170 may include a plurality of

pads

170a and 170 b. Then, the light emitting device 320 is placed on the circuit substrate 170, and the

electrodes

321a and 322a of the light emitting device 320 are respectively abutted against the

pads

170a and 170b of the circuit substrate 170.

In some embodiments, the steps further include connecting the electrode 321a of the light emitting device 320 and the pad 170a of the circuit substrate 170, and electrically connecting the electrode 322a of the light emitting device 320 and the pad 170b of the circuit substrate 170. The method for electrically connecting the electrode 321a and the pad 170a and the method for electrically connecting the electrode 322a and the pad 170b include eutectic bonding or other similar methods, but the invention is not limited thereto.

The display device 30 shown in fig. 3H differs from the display device 10 shown in fig. 1I in that: in the display device 30, the opening O3 is located on the side of the light emitting element 320 adjacent to the circuit substrate 170, and the opening O3 uses the space between the

electrodes

321a and 322a, so the opening O3 is formed without using an additional photolithography and etching process, and the opening O3 is located on the non-light-emitting surface of the light emitting element 320.

Fig. 4A to 4G are schematic cross-sectional views illustrating a process flow of a method for manufacturing a display device 40 according to an embodiment of the invention. Reference numerals and related contents of elements along the embodiments of fig. 2A to 2G are used, wherein the same reference numerals are used to denote the same or similar elements, and the description of the same technical contents is omitted. For the description of the omitted portions, reference may be made to the embodiments of fig. 2A to 2G, which will not be repeated in the following description.

First, referring to fig. 4A, a light emitting device 420 grown on a source substrate 110 is provided, the light emitting device 420 includes a first type semiconductor layer 421, a second type semiconductor layer 422, a light emitting layer 423 disposed between the first type semiconductor layer 421 and the second type semiconductor layer 422, and a plurality of

electrodes

421a, 422a electrically connected to the first type semiconductor layer 421 and the second type semiconductor layer 422, respectively. In the present embodiment, the plurality of

electrodes

421a, 422a are respectively located on opposite sides of the light emitting layer 423. That is, the light emitting device 420 is a Vertical (Vertical) micro light emitting diode.

Next, referring to fig. 4B, an opening O4 is formed in the electrode 421a, the first type semiconductor layer 421, the light emitting layer 423, the second type semiconductor layer 422 and the electrode 422 a. In the present embodiment, the opening O4 penetrates the layers of the light emitting element 420 to have a deeper depth. Thus, the supporting force of the connecting column 450a formed in the opening O4 to the light emitting device 420 can be increased, and the stability of the connecting column 450a suspending the light emitting device 420 can be improved. The formation of the opening O4 can be achieved by a multi-etching process, and an etchant selective to each layer of the light emitting device 420 can be selected in sequence to form the opening O4 according to the actual requirement.

Next, referring to fig. 4C, a connection layer 450 is formed on the light emitting device 420 and the source substrate 110, and the connection layer 450 is filled in the opening O4. In this embodiment, the connection layer 450 may be formed by sequentially forming a first layer 451, a second layer 452, a third layer 453, and a fourth layer 454, where the light absorption rate of the third layer 453 is greater than that of the fourth layer 454, the light absorption rate of the fourth layer 454 is greater than that of the second layer 452, and the light absorption rate of the second layer 452 is greater than that of the first layer 451. At least the third layer 453 or the fourth layer 454 of the connection layer 450 is a material that can be decomposed by reaction with laser light.

In the embodiment, the connection layer 450 may completely fill the opening O4, but the invention is not limited thereto. In some embodiments, the connection layer 450 may also fill the partial opening O4. The fourth layer 454 of the connection layer 450 may have an adhesive property, but the present invention is not limited thereto. In some embodiments, when the fourth layer 454 of the connection layer 450 is not adhesive, a layer of adhesive may be formed on the fourth layer 454.

Next, referring to fig. 4D, a carrier C7 is attached on the connection layer 450, and the light emitting device 420 is located between the source substrate 110 and the carrier C7, and then the source substrate 110 is removed.

Next, referring to fig. 4E, most of the connection layer 450 is removed, but a portion of the connection layer 450 between the opening O4 and the carrier C7 remains, so as to form a connection pillar 450a, wherein the connection pillar 450a includes a first layer 451a, a second layer 452a, a third layer 453a, and a fourth layer 454 a.

Next, referring to fig. 4F, a circuit substrate 170 is provided, and the circuit substrate 170 may include a plurality of

pads

170a and 170b on a surface thereof. Then, the light emitting device 420 and the circuit substrate 170 are aligned, such that the light emitting device 420 is located between the carrier C7 and the circuit substrate 170, and the front projection of the light emitting device 420 on the circuit substrate 170 overlaps the pad 170b of the circuit substrate 170. Then, the laser beam LB from the laser 180 is focused on the third layer 453a of the connection pillar 450a to burn the third layer 453a, so that the light emitting device 420 falls down to be transferred to the circuit substrate 170, and the electrode 422a of the light emitting device 420 directly contacts the pad 170 b. Since the third layer 453a of the connection column 450a has the greatest light absorption rate in the connection column 450a, the laser beam LB may easily decompose the third layer 453a by reaction with the third layer 453 a.

In some embodiments, the steps may further include electrically connecting the electrode 422a of the light emitting device 420 and the pad 170b of the circuit substrate 170. The method for electrically connecting the electrode 422a of the light emitting device 420 and the pad 170b of the circuit substrate 170 includes eutectic bonding or other similar methods, but the invention is not limited thereto.

Next, referring to fig. 4G, an insulating layer IS may be formed on the electrode 422a and the side of the pad 170b close to the pad 170a, and then the connecting wire 421c IS formed, so as to complete the display device 40 of the embodiment. In the present embodiment, the connecting wire 421c connects the electrode 421a of the light emitting device 420 and the pad 170a of the circuit substrate 170, and the insulating layer IS can prevent the connecting wire 421c from being short-circuited with the electrode 422a or the pad 170 b.

The display device 40 shown in fig. 4G is different from the display device 20 shown in fig. 2G in that: in the display device 40, the light emitting elements 420 are vertical micro light emitting diodes; the opening O4 penetrates the electrode 421a, the first type semiconductor layer 421, the light emitting layer 423, the second type semiconductor layer 422 and the electrode 422a of the light emitting device 420 without a lateral blind hole; and connecting stud 450a comprises multiple layers. In addition, the electrode 421a of the light emitting device 420 is connected to the pad 170a of the circuit board 170 through the connection wire 421c, and the electrode 422a of the light emitting device 420 is directly connected to the pad 170b of the circuit board 170.

In summary, in the display device according to the embodiments of the invention, the openings in the light emitting elements are used to adjust the action range of the laser beam during the laser transfer process, so that the light emitting elements can be accurately transferred onto the circuit substrate, and the display device has an array of light emitting elements with accurate mass transfer.

Although the present invention has been described with reference to the above embodiments, it should be understood that various changes and modifications can be made therein by those skilled in the art without departing from the spirit and scope of the invention as defined in the appended claims.

Claims

1. A display device, comprising:

a circuit substrate; and

and the light-emitting element is electrically connected with the circuit substrate and is provided with an opening, wherein the opening is positioned at one side of the light-emitting element, which is close to or far away from the circuit substrate.

2. The display device according to claim 1, wherein an orthogonal projection of the opening on the circuit substrate overlaps an orthogonal projection of a center of gravity of the light-emitting element on the circuit substrate.

3. The display device according to claim 1, wherein the light-emitting element comprises two electrodes, and the opening is located at least partially outside the two electrodes.

4. The display device according to claim 1, wherein the light-emitting element comprises two electrodes, and the opening is located between the two electrodes.

5. The display device as claimed in claim 1, wherein the opening is located on a light emitting surface or a non-light emitting surface of the light emitting element.

6. The display device according to claim 1, wherein the opening penetrates the light emitting element.

7. The display device of claim 1, wherein a cross-section of the opening has a regular trapezoid or an inverted trapezoid.

8. The display device of claim 1, wherein the opening has a lateral blind hole therein.

9. The display device according to claim 1, wherein an aperture of the opening is smaller than 1/3 of a width of the light emitting element.

10. The display device according to claim 1, wherein an aperture of the opening is less than or equal to 3 μm.

11. The display device of claim 1, wherein the opening has a depth greater than or equal to 1 μ ι η.

12. The display device of claim 1, wherein the circuit substrate comprises an array of active elements.

13. The display device of claim 1, further comprising a connection post at least partially located in the opening.

14. The display device of claim 13, wherein the connecting stud comprises a plurality of layers, and the plurality of layers have different concentrations, light absorption rates, or light transmission rates.

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

providing a light-emitting element, wherein the light-emitting element is positioned on a first carrier plate;

forming an opening on the surface of the light-emitting element away from the first carrier plate;

forming a connecting layer on the surface, wherein the connecting layer is filled in the opening;

fixing a second carrier plate on the connecting layer, so that the light-emitting element is positioned between the first carrier plate and the second carrier plate;

removing the first carrier plate;

removing the connecting layer, and reserving the connecting layer between the opening and the second carrier plate to form a connecting column;

providing a third carrier plate, and aligning the light-emitting element with the third carrier plate, wherein the light-emitting element is located between the second carrier plate and the third carrier plate; and

focusing the laser beam on the connecting column to separate the light-emitting element from the second carrier plate, so that the light-emitting element is transferred onto the third carrier plate.

16. The method as claimed in claim 15, wherein the opening is located on a light emitting surface or a non-light emitting surface of the light emitting element.

17. The method according to claim 15, wherein an orthogonal projection of the opening on the surface overlaps an orthogonal projection of a center of gravity of the light-emitting element on the surface.

18. The method for manufacturing a display device according to claim 15, wherein the opening penetrates the light emitting element.

19. The method of claim 15, wherein the third carrier is a circuit substrate.

20. The method of manufacturing a display device according to claim 15, wherein the connection layer comprises a plurality of layers, and the plurality of layers have different concentrations, light absorption rates, or light transmittance rates.