An LED display device and a mass transfer method

Abstract

The present invention relates to the field of display manufacturing, and particularly to an LED display device, which includes a display backplane, a plurality of first LED chips, a plurality of second LED chips, and a plurality of third LED chips. A plurality of first bosses and a plurality of second bosses are formed on the display backplane. The first LED chips are disposed on the first bosses, the second LED chips are disposed on the second bosses, and the height H11 of the first bosses is greater than the height H22 of the second bosses. At the same time, the present invention also relates to a mass transfer method for transferring micro-components, which does not require a separate transfer head. Only a temporary transfer head made of photosensitive resin is needed to complete the transfer of LED chips, with high transfer accuracy and high efficiency.

Description

Technical Field

[0001] The present invention relates to the technical field of manufacturing LED display devices, and in particular, to an LED display device and a method for transferring a large number of LED chips. Background Art

[0002] The development of micro-LEDs is one of the hotspots in future display technologies. However, there are many technical difficulties and complexities, especially its key technology - the mass transfer technology. With the development of technology, many technical branches have emerged in the mass transfer technology so far, such as electrostatic adsorption, laser ablation, etc.

[0003] At the current stage, for the mass transfer process of red, green, and blue (RGB) micro-LEDs, a method of transferring in batches is generally adopted, that is, only one color of micro-LED chips can be transferred at a time, and the micro-LED chips of corresponding shapes are made to fall into the loading groove by vibration and wind force. Therefore, for RGB micro-LED chips of the same shape, three mass transfer processes are required. Since the size of micro-LED chips is below 100um, in the process of mass transfer, a traditional transfer head is used for transfer. Then, the transfer head needs to be made very small to match it, and the accuracy requirement is very high. Therefore, the manufacturing requirement for the transfer equipment is also very high.

[0004] In semiconductor packaging, some polymers with high elasticity and easy processing are often used. These polymers can form a solid state at room temperature after spin coating. Usually, after making a mold, a polymer material is poured into the mold, and after curing the mold, transfer micro-columns are formed, and the micro-components are grabbed by aligning the columns. However, this method has a relatively complex process. More importantly, when using the micro-columns to grab micro-components, precise alignment is required, which easily leads to a decrease in the product yield. Summary of the Invention

[0005] Based on the above problems, the present invention designs a structure of an LED display device, which can well realize the mass transfer of micro-LED chips. The specific structure is as follows:

[0006] An LED display device, which includes a display backplane, and the display backplane is divided into a plurality of pixel regions in an array;

[0007] Each pixel region includes a first LED chip, a second LED chip, and a third LED chip, and a first boss and a second boss provided on the display backplane;

[0008] The first LED chip is disposed on the first boss,

[0009] The second LED chip is disposed on the second boss,

[0010] The third LED chip is disposed on a display backplane within the pixel region.

[0011] The height H11 of the first boss is greater than the height H22 of the second boss.

[0012] Further, the heights of the second LED chip and the third LED chip are h2 and h3 respectively.

[0013] The height H11 of the first boss and the height H22 of the second boss satisfy the following conditions:

[0014] H22 ≥ h3, H11 ≥ h2 + h3.

[0015] This application further includes a mass transfer method, which includes the steps of:

[0016] S10 provides a first growth substrate, on which there are a plurality of first LED chips, and the electrodes of the first LED chips face away from the first growth substrate.

[0017] S11 provides a first temporary substrate, on which an adhesive is provided, the electrodes of the first LED chips are adhered to a first adhesive layer of the first temporary substrate, and the first growth substrate is peeled off.

[0018] S12 coats a photosensitive resin on the first temporary substrate provided with the first LED chips to form a first photosensitive resin layer, and the thickness H1 of the first photosensitive resin layer is greater than the height h1 of the first LED chips, that is, H1 > h1.

[0019] S13 covers a second temporary substrate on the photosensitive resin layer, and the second temporary substrate is made of a light-transmitting material.

[0020] Provide a patterning mask to block the light rays directed at the first LED chips that do not need to be transferred, expose the corresponding part of the first photosensitive resin layer of the first LED chips to be transferred to cure it, and remove the unexposed first photosensitive resin layer through a developer. The remaining photosensitive resin layer serves as a first transfer head.

[0021] S14 selectively peels off the first LED chips to be transferred from the adhesive layer by means of laser peeling, so that the first LED chips adhere to the second temporary substrate through the first transfer head.

[0022] S15 moves the second temporary substrate, transfers the LED chips on the second temporary substrate to the display backplane, dissolves the transfer head through a stripping solution, and separates the LED chips from the second temporary substrate to complete the transfer of the LED chips.

[0023] Further, the method further includes:

[0024] Providing a second growth substrate, on which there are a plurality of second LED chips, and the electrodes of the second LED chips face away from the second growth substrate;

[0025] Providing a third temporary substrate, on which an adhesive is provided, adhering the electrodes of the second LED chips to the second adhesive layer of the third temporary substrate, and peeling off the second growth substrate;

[0026] Coating a photosensitive resin on the third temporary substrate provided with the second LED chips to form a second photosensitive resin layer, and the thickness H2 of the second photosensitive resin layer is greater than the height h2 of the second LED chips, that is, H2>h2. If the height h2 of the second LED chips is not equal to the height h1 of the first LED chips, the preset height of the second photosensitive resin layer covering the second LED chips is H2, satisfying the following condition: H2 - h2>|h2 - h1|;

[0027] Covering a fourth temporary substrate on the second photosensitive resin layer, and the fourth temporary substrate is made of a light-transmitting material;

[0028] Providing a patterning mask to block the light rays directed to the second LED chips that do not need to be transferred, exposing the corresponding part of the second photosensitive resin layer of the second LED chips to be transferred, curing it, and removing the unexposed second photosensitive resin layer through a developer, and the remaining second photosensitive resin layer serves as a second transfer head;

[0029] Selectively peeling off the second LED chips to be transferred from the adhesive layer by means of laser peeling, so that the second LED chips adhere to the fourth temporary substrate through the second transfer head;

[0030] Moving the fourth temporary substrate, transferring the LED chips on the fourth temporary substrate to the display backplane, and separating the LED chips from the fourth temporary substrate by dissolving the second transfer head with a stripping solution to complete the transfer of the second LED chips.

[0031] Further, the method further includes:

[0032] Providing a third growth substrate, on which there are a plurality of third LED chips, and the electrodes of the third LED chips face away from the third growth substrate;

[0033] Providing a fifth temporary substrate, on which an adhesive is provided, adhering the electrodes of the third LED chips to the third adhesive layer of the fifth temporary substrate, and peeling off the third growth substrate;

[0034] Apply a photosensitive resin on the fifth temporary substrate provided with the third LED chip to form a third photosensitive resin layer. The thickness H3 of the third photosensitive resin layer is greater than the height h3 of the third LED chip, that is, H3>h3. If the height h3 of the third LED chip, the height h2 of the second LED chip, and the height h1 of the first LED chip are not equal to each other, the preset height of the third photosensitive resin layer covering the third LED chip is H3, satisfying the following conditions: H3 - h3 > |h3 - h1| and H3 - h3 > |h3 - h2|;

[0035] Cover a sixth temporary substrate on the third photosensitive resin layer. The sixth temporary substrate is made of a light-transmitting material;

[0036] Provide a patterned mask to block the light rays directed at the third LED chip that do not need to be transferred, expose the corresponding part of the third photosensitive resin layer of the third LED chip to be transferred, cure it, and remove the unexposed third photosensitive resin layer with a developer. The remaining third photosensitive resin layer serves as the third transfer head;

[0037] Selectively peel the third LED chip to be transferred from the adhesive layer by laser stripping, so that the third LED chip adheres to the sixth temporary substrate through the third transfer head;

[0038] Move the sixth temporary substrate to transfer the LED chip on the sixth temporary substrate to the display backplane, dissolve the third transfer head with a stripping solution, and separate the LED chip from the sixth temporary substrate to complete the transfer of the third LED chip.

[0039] Further, after step S14 and before step S15, the following steps are also included:

[0040] S21 Provide a second growth substrate, on which a plurality of second LED chips are formed. The height of the second LED chip is h2;

[0041] S22 Provide a third temporary substrate, on which a second adhesive layer is formed. Adhere the second LED chip to the third temporary substrate. After removing the second growth substrate, apply a photosensitive resin material on the third temporary substrate provided with the second LED chip to form a second photosensitive resin layer with a thickness of H21, and satisfy: H21≥H1;

[0042] S23 Form a plurality of first grooves corresponding to the first LED chips on the second photosensitive resin layer, and cover the second photosensitive resin layer with a second temporary substrate picking up a plurality of the first LED chips;

[0043] S24 provides a graphical mask to block the light rays directed at the second LED chips that do not need to be transferred, expose the corresponding part of the second photosensitive resin layer of the second LED chips to be transferred, cure it, remove the unexposed second photosensitive resin layer through a developer, and the remaining second photosensitive resin layer serves as the second transfer head;

[0044] S25 selectively peels off the second LED chips to be transferred from the adhesive layer by laser stripping, so that the second LED chips adhere to the second temporary substrate through the second transfer head.

[0045] Further, after step S25 and before step S15, the following steps are also included:

[0046] S31 provides a third growth substrate, on which a plurality of third LED chips are formed, and the height of the third LED chips is h3;

[0047] S32 provides a fourth temporary substrate, on which a third adhesive layer is formed, adheres the third LED chips to the fourth temporary substrate, removes the third growth substrate, and coats a photosensitive resin material on the fourth temporary substrate provided with the third LED chips to form a third photosensitive resin layer with a thickness of H31, and satisfies: H31≥H2 + h3;

[0048] S33 forms a plurality of second grooves and third grooves corresponding to the first LED chips and the second LED chips on the third photosensitive resin layer, and covers the second temporary substrate picking up a plurality of the first LED chips and the second LED chips on the third photosensitive resin layer;

[0049] S34 provides a graphical mask to block the light rays directed at the third LED chips that do not need to be transferred, expose the corresponding part of the third photosensitive resin layer of the third LED chips to be transferred, cure it, remove the unexposed third photosensitive resin layer through a developer, and the remaining third photosensitive resin layer serves as the third transfer head;

[0050] S35 selectively peels off the third LED chips to be transferred from the third adhesive layer by laser stripping, so that the third LED chips adhere to the second temporary substrate through the third transfer head.

[0051] Further,

[0052] The display backplane includes a plurality of first bosses and a plurality of second bosses,

[0053] The first LED chips on the second temporary substrate are bonded to the first bosses,

[0054] The second LED chip on the second temporary substrate is bonded to the second boss.

[0055] Further, the height of the first boss is H11, the height of the second boss is H22, and they satisfy

[0056] the following conditions:

[0057] H22 ≥ h3, H11 ≥ H22 + h2, H11 = H31 - H1 and H22 = H31 - H21.

[0058] Further, the method for forming the first groove and the second groove is exposure and development or etching.

[0059] The beneficial effects of the present invention are as follows:

[0060] In the LED display device structure described in the present invention, the placement heights of the three different LED chips are different, which is convenient for the "transfer head" to pick them up in batches and transfer them at one time, saving processes.

[0061] In the mass transfer method described in the present invention, the corresponding "transfer head" is directly formed on the growth substrate through selective photocuring of the resin, eliminating the need for specially manufacturing transfer equipment and reducing the difficulty of mass transfer. And when needed, the RGB three-color LED chips can be picked up in batches and transferred to the display backplane at one time, without three transfers, and the transfer efficiency is higher. Description of the Drawings

[0062] Figure 1 is a structure of an LED display device;

[0063] Figure 2 is a flowchart of the method in Embodiment 2

[0064] Figure 3 is a state diagram of the first LED chip in Embodiment 2 located on the first growth substrate;

[0065] Figure 4 is a state diagram of the first LED chip transferred to the first temporary substrate in Embodiment 2;

[0066] Figure 5 is a state diagram of forming the first photosensitive resin layer in Embodiment 2;

[0067] Figure 6 is a state diagram after exposure and development of the first photosensitive resin layer in Embodiment 2;

[0068] Figure 7 is a schematic diagram of separating the first LED chip from the first temporary substrate in Embodiment 2;

[0069] Figure 8Schematic diagram of transferring the first LED chip to the display backplane in Example 2;

[0070] Figure 9 Schematic diagram of the second LED chip located on the second growth substrate;

[0071] Figure 10 Schematic diagram of transferring the second LED chip to the third temporary substrate;

[0072] Figure 11 Schematic diagram of forming the second photosensitive resin layer;

[0073] Figure 12 Schematic diagram of forming the second transfer head;

[0074] Figure 13 Schematic diagram of separating the third LED chip to be transferred from the fourth temporary substrate;

[0075] Figure 14 Schematic diagram of transferring the second LED chip to the display backplane;

[0076] Figure 15 Schematic diagram of the third LED chip located on the third growth substrate;

[0077] Figure 16 Schematic diagram of transferring the third LED chip to the fifth temporary substrate;

[0078] Figure 17 Schematic diagram of forming the third photosensitive resin layer on the third LED chip;

[0079] Figure 18 Schematic diagram after forming the third transfer head;

[0080] Figure 19 Schematic diagram of separating the third LED chip to be transferred from the third adhesive layer;

[0081] Figure 20 Schematic diagram of transferring the third LED chip to the display backplane;

[0082] Figure 21 Flowchart of the method in Example 3;

[0083] Figure 22 Schematic diagram after picking up the first LED chip according to the method in Example 2;

[0084] Figure 23 Schematic diagram of the initial state of the second LED chip in Example 3;

[0085] Figure 24 Schematic diagram of forming the second photosensitive resin layer in Example 3;

[0086] Figure 25 Schematic diagram of the second temporary substrate covering the second photosensitive resin layer;

[0087] Figure 26 Schematic diagram of the process of forming the second transfer head;

[0088] Figure 27 Intention of separating the second LED chip from the third temporary substrate;

[0089] Figure 28 Schematic diagram of the third LED chip located on the growth substrate;

[0090] Figure 29 Schematic diagram of the process of transferring the third LED chip to the fourth temporary substrate;

[0091] Figure 30 Schematic diagram of the structure of the second temporary substrate covering the third photosensitive resin layer;

[0092] Figure 31 Schematic diagram of the process of forming the third transfer head;

[0093] Figure 32 Schematic diagram of picking up the first LED chip, the second LED chip and the third LED chip;

[0094] Figure 33 Schematic diagram of transferring the first LED chip, the second LED chip and the third LED chip to the display backplane.

[0095] Explanation of the reference numerals in the figure:

[0096] The first growth substrate 111, the first temporary substrate 112, the photosensitive resin layer 113, the second temporary substrate 114 / 211, the first transfer head 115, the patterned mask 116, the first LED chip 110 / 210, the display backplane 100 / 200, the second LED chip 120 / 220, the third temporary substrate 121, the second transfer head 1231 / 225, the third LED chip 130 / 230, the fourth temporary substrate 124 / 310, the third transfer head 1331 / 323, the first boss 140 / 241, the second boss 150 / 242, the second growth substrate 221, the third temporary substrate 222, the second adhesive layer 2221, the second photosensitive resin layer 123 / 223, the first groove 224, the second groove 321, the third groove 322, the third adhesive layer 311, the third photosensitive resin layer 133 / 320, the fifth temporary substrate 132, the sixth temporary substrate 134. Detailed implementation mode

[0097] Next, the technical solutions in the embodiments of the present application will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present application. The described embodiments are only a part of the embodiments of the present application, rather than all the embodiments.

[0098] In the present application, the terms "first", "second", and "third" are only used for descriptive purposes, and cannot be construed as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Therefore, the features defined with "first", "second", and "third" may explicitly or implicitly include at least one of such features. In the description of the present application, the meaning of "a plurality" is at least two, such as two, three, etc., unless otherwise specifically defined.

[0099] Embodiment 1

[0100] As Figure 1 shown is the structure of the LED display device described in the present invention.

[0101] A structure of an LED display device includes a display backplane 100. The display backplane 100 is divided into a plurality of pixel regions in an array. Each pixel region includes a first LED chip 110, a second LED chip 120, and a third LED chip 130. A plurality of first bosses 140 and a plurality of second bosses 150 are formed on the display backplane 100. The first LED chip 110 is disposed on the first boss 140, the second LED chip 120 is disposed on the second boss 150, and the height H11 of the first boss 140 is greater than the height H22 of the second boss 150.

[0102] The preset heights of the second LED 120 chip and the third LED chip 130 are h2 and h3 respectively, then H22≥h3, H11≥h2 + h3.

[0103] Correspondingly, electrodes corresponding to the first LED chip 110 and the second LED chip 120 are respectively disposed on the first boss 140 and the second boss 150, and are bonded to the electrodes on the first LED chip 110 and the second LED chip 120. The third LED chip 130 is disposed on the display backplane 100 and is bonded to the corresponding electrode on the display backplane 100, thereby completing the electrical connection of the first LED chip 110, the second LED chip 120, and the third LED chip 130 to the display backplane 100.

[0104] By setting bosses with different heights to place the LED chips, when picking up different chips, transfer heads with different heights can be used to pick up the first LED chip 110, the second LED chip 120, and the third LED chip 130 respectively, and transfer them to the display backplane 100 at the same time, avoiding separate transfer of each type of LED chip and streamlining the process.

[0105] In this embodiment, the first LED chip 110 is a red chip, the second LED chip 120 is a green chip, and the third LED chip is a blue chip. It can be understood that the types of these chips can be replaced with each other, and they can also be other types of chips.

[0106] Embodiment 2

[0107] As Figures 2 - 9 shown in the following is a method for massive transfer of the present invention, Figure 2 which is the flowchart of the method for this embodiment, and the specific method steps are as follows.

[0108] S10 provides a first growth substrate 111, and there are multiple first LED chips 110 on the first growth substrate 111.

[0109] Please refer to Figure 3 , the electrodes of the first LED chip 110 face away from the first growth substrate 111. The first LED chip 110 is a micro-LED chip in the red light band, and other types of micro-LEDs can also be selected according to requirements.

[0110] S11 provides a first temporary substrate 112, and there is an adhesive layer 1121 on the first temporary substrate 112. The electrodes of the first LED chip 110 are adhered to the adhesive layer 1121 of the first temporary substrate 112, and then the first growth substrate 111 is peeled off.

[0111] Please refer to Figure 4 , the method of peeling off the first growth substrate 111 is laser peeling. By irradiating the first growth substrate with light of a specific wavelength, the adhesion between the first LED chip 110 and the first growth substrate 111 is lost, so that the first LED chip 110 is transferred to the first temporary substrate 112.

[0112] S12 coats a photosensitive resin on the first temporary substrate 112 provided with the first LED chip 110 to form a first photosensitive resin layer 113.

[0113] Please refer to Figure 5 , the thickness of the first photosensitive resin layer 113 is H1, and the height of the first LED chip 110 is h1. Then, the condition H1 > h1 needs to be satisfied, so that the photosensitive resin layer completely covers the first LED chip 110. The photosensitive resin layer 113 is cured by photosensitive resin, that is, it is cured after irradiating light of a specific wavelength and requires a specific chemical solvent to dissolve, which is different from the chemical solvent required to dissolve the uncured photosensitive resin.

[0114] After S13 exposes and develops the photosensitive resin layer 113, multiple first transfer heads 115 are formed.

[0115] Please refer to Figure 6, a second temporary substrate 114 is covered on the photosensitive resin layer 113. A patterned mask (not shown in the figure) is provided to block the light rays directed above the first LED chip 110 that does not need to be transferred. The unblocked photosensitive resin layer 113 is exposed to light to cure it. The unexposed photosensitive resin layer 113 is dissolved and removed with a developer to obtain a plurality of first transfer heads 115. The first transfer heads 115 are connected to the first LED chips 110 to be transferred.

[0116] The second temporary substrate 114 is made of a light-transmitting material, so light can pass through it to enable smooth exposure. The preferred light-transmitting material is quartz glass.

[0117] S14 Selectively peel the first LED chips 110 to be transferred from the first adhesive layer 1121 with a laser, so that the first LED chips 110 to be transferred adhere to the second temporary substrate 114 through the first transfer heads 115.

[0118] Please refer to Figure 7 , the first temporary substrate is made of a light-transmitting material. Part of the light is blocked by a patterned mask plate 116, so that the light can only reach the area corresponding to the first LED chips 110 to be transferred. The first adhesive layer 1121 is a photosensitive material and loses its viscosity after being irradiated with a laser, so that the first LED chips 110 are smoothly separated from the first temporary substrate 112.

[0119] S15 Move the second temporary substrate 114 to transfer the first LED chips 110 to the display backplane 100. Remove the first transfer heads 115 to separate the first LED chips 110 from the second temporary substrate 114, and complete the transfer of the first LED chips 110.

[0120] Please refer to Figure 8 , the first transfer heads 115 can be dissolved by a specific stripping solution. After dissolution, the second temporary substrate 114 is separated from the first LED chips 110. The electrodes of the first LED chips 110 and the electrodes on the display backplane 100 can be fixed on the display backplane 100 through thermal bonding to complete the transfer of the first LED chips.

[0121] S16 Provide a second growth substrate 121, and there are a plurality of second LED chips 120 on the second growth substrate 121. The electrodes of the second LED chips 120 face away from the second growth substrate. Please refer to Figure 9 .

[0122] S17 Provide a third temporary substrate 122, and a second adhesive layer 1221 is provided on the third temporary substrate 122. Adhere the electrodes of the second LED chips 120 to the second adhesive layer 1221 on the third temporary substrate 122, and peel the second growth substrate 121. Please refer to Figure 10。In this embodiment, the adhesive is a photosensitive adhesive, which can lose its adhesiveness by irradiating light of a specific wavelength, thus facilitating the peeling of the chip.

[0123] S18 Coating a photosensitive resin on the third temporary substrate 122 provided with the second LED chip 120 to form a second photosensitive resin layer 123. The thickness H2 of the second photosensitive resin layer 123 is greater than the height h2 of the second LED chip 120, that is, H2>h2. If the height h2 of the second LED chip 120 is not equal to the height h1 of the first LED chip 110, the preset height of the second photosensitive resin layer 123 covering the second LED chip 120 is H2, satisfying the following condition: H2 - h2 > |h2 - h1|. Please refer to Figure 11 。

[0124] After exposing and developing the second photosensitive resin layer 123 in S19, a second transfer head 1231 is formed.

[0125] Cover a fourth temporary substrate 124 on the second photosensitive resin layer 123. The fourth temporary substrate 124 is made of a light-transmitting material, providing a patterned mask to block the light irradiating the second LED chip 120 that does not need to be transferred, exposing the corresponding part of the second photosensitive resin layer 123 of the second LED chip 120 to be transferred to cure it, and removing the unexposed second photosensitive resin layer 123 with a developer. The remaining second photosensitive resin layer 123 serves as the second transfer head 1231. Please refer to Figure 12 。

[0126] In S110, the second LED chip 120 to be transferred is selectively peeled from the second adhesive layer 1221 by laser peeling. The second LED chip 120 is adhered to the fourth temporary substrate 124 through the second transfer head 1231. Please refer to Figure 13 。

[0127] In S111, move the fourth temporary substrate 124 to transfer the LED chip on the fourth temporary substrate 124 to the display backplane 100. Dissolve the second transfer head 1231 with a stripping solution to separate the LED chip from the fourth temporary substrate 124, completing the transfer of the second LED chip 120. Please refer to Figure 14 。

[0128] In S112, provide a third growth substrate 131, and there are multiple third LED chips 130 on the third growth substrate 131. The electrodes of the third LED chips 130 face away from the third growth substrate 131. Please refer to Figure 15 。

[0129] S113 provides a fifth temporary substrate 132 with an adhesive on it, and adheres the electrodes of the third LED chip 130 to the third adhesive layer 1321 of the fifth temporary substrate 132, then peels off the third growth substrate 131. Please refer to Figure 16 . In this embodiment, the adhesive is a photosensitive adhesive, and its viscosity can be lost by irradiating light with a specific wavelength, which is convenient for peeling off the chip.

[0130] S114 coats a photosensitive resin on the fifth temporary substrate 132 provided with the third LED chip 130 to form a third photosensitive resin layer 133.

[0131] The thickness H3 of the third photosensitive resin layer 133 is greater than the height h3 of the third LED chip 130, that is, H3>h3. If the heights h3 of the third LED chip 130, h2 of the second LED chip 120, and h1 of the first LED chip 110 are not equal to each other, the preset height of the third photosensitive resin layer 133 covering the third LED chip 130 is H3, satisfying the following conditions: H3 - h3 > |h3 - h1| and H3 - h3 > |h3 - h2|. Please refer to Figure 17 . It is necessary to meet this height condition so that the third LED chip 130 will not collide with the already transferred first LED chip 110 and second LED chip 120 when being transferred to the display backplane 100.

[0132] S115 After exposing and developing the third photosensitive resin layer 133, a third transfer head 1331 is formed.

[0133] Cover a sixth temporary substrate 134 on the third photosensitive resin layer 133. The sixth temporary substrate 134 is made of a light-transmitting material; provide a patterned mask to block the light rays directed to the third LED chip 130 that do not need to be transferred, expose the corresponding part of the third photosensitive resin layer 133 of the third LED chip 130 to be transferred to cure it, and remove the unexposed third photosensitive resin layer 133 through a developer. The remaining third photosensitive resin layer 133 serves as the third transfer head 1331. Please refer to Figure 18 .

[0134] S116 Selectively peel off the third LED chip 130 to be transferred from the third adhesive layer 1321 by laser peeling, so that the third LED chip 130 adheres to the sixth temporary substrate 134 through the third transfer head 1331. Please refer to Figure 19 . The specific operation method is to provide a patterned mask to block the light rays directed to the third LED chip 130 that do not need to be transferred, so that only the third LED chip 130 to be transferred is peeled off from the third adhesive layer 1321.

[0135] Move the sixth temporary substrate 134 of S117, transfer the third LED chip 130 on the sixth temporary substrate 134 to the display backplane 100, dissolve the third transfer head 1331 with the stripping liquid, separate the third LED chip 130 from the sixth temporary substrate 134, and complete the transfer of the three LED chips 130. Please refer to Figure 20 When the stripping liquid dissolves the third transfer head 1331, no mechanical stress is generated, so it will not affect the chip, which is also one of the advantages of the present invention.

[0136] Currently, the types of LED chips are usually three according to their different wavelength bands, namely red-wavelength-band LED chips, green-wavelength-band LED chips, and blue-wavelength-band LED chips. In this embodiment, the first LED chip 110 is a red-wavelength-band LED chip, the second LED chip 120 is a green-wavelength-band LED chip, and the third LED chip 130 is a blue-wavelength-band LED chip. In other embodiments, other different combinations of LED chips can also be used, and this embodiment is not limiting.

[0137] Embodiment 3

[0138] As Figures 21 - 33 shown, a mass transfer method of this embodiment is shown, where Figure 21 This is the flowchart of the method of this embodiment, and the specific method steps are as follows.

[0139] S20 Use the method described in steps S11 - S14 of Embodiment 2, and a plurality of first transfer heads 212 formed on the second temporary substrate 211 pick up a plurality of first LED chips 210.

[0140] Please refer to Figure 22 , the first LED chip 210 adheres to the first transfer head 212, and the position and quantity of the first transfer head 212 correspond to the first LED chip 210 one by one. The first transfer head 212 is formed by exposing and developing a photosensitive resin, and its material is the cured photosensitive resin.

[0141] S21 Provide a second growth substrate 221, on which a plurality of second LED chips 220 are formed, and the height of the second LED chip 220 is h2.

[0142] Please refer to Figure 23 , the electrodes of the second LED chip 220 face away from the side of the second growth substrate 221, and this state is the structure after the second LED chip 210 is manufactured.

[0143] S22 provides a third temporary substrate 222, on which a second adhesive layer 2221 is formed. The second LED chip 220 is adhered to the third temporary substrate 222. After removing the second growth substrate 221, a photosensitive resin material is coated on the second LED chip 220, and after curing, a second photosensitive resin layer 223 is formed.

[0144] Please refer to Figure 24 , the method for removing the second growth substrate 221 is laser irradiation removal. After irradiating the second growth substrate 221 with a laser, the adhesion between the second growth substrate 221 and the second LED chip 220 is lost, and thus they are separated. After coating a liquid photosensitive resin material on the second LED chip 220, the photosensitive resin material flows and covers the entire second LED chip 220. After curing, a second photosensitive resin layer 223 is formed, with a thickness of H21, and the height condition to be satisfied is H21≥H1.

[0145] S23 forms a plurality of first grooves 224 corresponding to the first LED chips 210 on the second photosensitive resin layer 223, and covers the second photosensitive resin layer 223 with a second temporary substrate 221 that picks up a plurality of first LED chips 210.

[0146] Please refer to Figure 25 , a plurality of first grooves 224 corresponding to the first LED chips 210 are formed on the second photosensitive resin layer 223, and the second temporary substrate 211 that picks up a plurality of first LED chips 210 is covered on the second photosensitive resin layer 223. The positions of the first LED chips 210 connected to the second temporary substrate 211 correspond to the first grooves 224. The method for forming the first grooves 224 is to remove part of the photosensitive resin material by exposure and development, or to remove part of the photosensitive resin material by etching.

[0147] S24 provides a patterned mask to block the light rays directed at the second LED chips 220 that do not need to be transferred, exposes the corresponding part of the second photosensitive resin layer 223 of the second LED chips 220 to be transferred, so that it cures, and removes the unexposed second photosensitive resin layer 223 through a developer. The remaining second photosensitive resin layer 223 serves as the second transfer head 225.

[0148] Please refer to Figure 26 , the second temporary substrate 211 is a light-transmitting material and can transmit light. A patterned mask (not shown in the figure) covers the second temporary substrate 211, so that only part of the light reaches the second photosensitive resin layer 223 during exposure. The exposed second photosensitive resin layer 223 cures to form the second transfer head 225, which is connected to the second temporary substrate 211 and the second LED chips 220. Then, the uncured second photosensitive resin layer 223 is dissolved and removed through a developer. The second transfer head 225 is connected to the second LED chips 220.

[0149] The second LED chip 220 to be transferred is selectively peeled off from the adhesive layer by laser peeling, so that the second LED chip 220 adheres to the second temporary substrate 211 through the second transfer head 225.

[0150] Please refer to Figure 27 , the adhesive layer is made of a photosensitive material and will lose its viscosity after being irradiated with light of a specific wavelength. Therefore, a patterned mask can be used to block the light from reaching the second LED chip 220 that does not need to be removed, so that the light only reaches the second LED chip 220 that needs to be removed, and the second LED chip 220 is separated from the third temporary substrate 222.

[0151] S31 provides a third growth substrate 300, on which a plurality of third LED chips 230 are formed. The height of the third LED chip 230 is h3. Please refer to Figure 28 .

[0152] S32 provides a fourth temporary substrate 310, on which a third adhesive layer 311 is formed. The third LED chip 230 is adhered to the fourth temporary substrate 310. After removing the third growth substrate 300, a photosensitive resin material is coated on the fourth temporary substrate 310 provided with the third LED chip 230 to form a third photosensitive resin layer 320 with a thickness of H31, and it satisfies: H31≥H2 + h3. Please refer to Figure 29 .

[0153] S33 forms a plurality of second grooves 321 and third grooves 322 corresponding to the first LED chip 210 and the second LED chip 220 on the third photosensitive resin layer 320, and covers the second temporary substrate 211 picking up a plurality of first LED chips 210 and second LED chips 220 on the third photosensitive resin layer 320. Please refer to Figure 30 .

[0154] S34 provides a patterned mask to block the light from reaching the third LED chip 230 that does not need to be transferred, exposes the corresponding part of the third photosensitive resin layer 320 of the third LED chip 230 to be transferred to cure it, and removes the unexposed third photosensitive resin layer 320 through a developer. The remaining third photosensitive resin layer 320 serves as the third transfer head 323. Please refer to Figure 31 .

[0155] S35 selectively peels off the third LED chip 230 to be transferred from the third adhesive layer 311 by laser peeling, so that the third LED chip 230 adheres to the second temporary substrate 211 through the third transfer head 323.

[0156] Please refer to Figure 32, a plurality of third transfer heads 323 are formed on the second temporary substrate 211, and the third transfer heads 323 are connected to the third LED chips 230.

[0157] The preset height of the third LED chip 310 is h3, and the thickness of the third photosensitive resin layer 320 formed during the fabrication of the third transfer head 323 is H3, then H3 > H2 > H1.

[0158] S36 provides a display backplane 200 having a plurality of first bosses 241 and second bosses 242, and simultaneously transfers the first LED chips 210, the second LED chips 220, and the third LED chips 230 on the second temporary substrate 211 to the display backplane 200.

[0159] Please refer to Figure 33 , the position of the first LED chip 210 corresponds to the first boss 241, the position of the second LED chip 220 corresponds to the second boss 242, and then the second temporary substrate 211 is removed. The height of the first boss is H11 and the height of the second boss is H22, then the height relationship H22 ≥ h3, H11 ≥ H22 + h2, H11 = H31 - H1 and H22 = H31 - H21 need to be satisfied simultaneously. Only by satisfying this height relationship can each type of LED chip not collide with other structures during the transfer process, so as to be transferred smoothly.

[0160] The second temporary substrate 211 is made of a light-transmitting material. By laser irradiation, the first LED chip 210, the second LED chip 220, and the third LED chip 230 can be separated from the second temporary substrate 211, and the electrodes of the first LED chip 210, the second LED chip 220, and the third LED chip 230 are heated and bonded to the electrodes on the first boss 241, the second boss 242, and the display backplane 200 respectively for fixed connection.

[0161] The three types of LED chips described in the present invention are RGB three-color LED chips according to actual applications, and their transfer order is not limited and is not limited to this embodiment.

[0162] The mass transfer method described in the present invention can transfer LED chips without fabricating transfer heads, and has high transfer efficiency and high precision.

[0163] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall be included in the protection scope of the present invention.

[0164] The basic principles of the present disclosure have been described above in connection with specific embodiments. However, it should be noted that the advantages, benefits, effects, etc. mentioned in the present disclosure are only examples and not limitations, and it cannot be considered that these advantages, benefits, effects, etc. are essential for each embodiment of the present disclosure. Additionally, the specific details disclosed above are only for the purposes of illustration and facilitating understanding, rather than limitations, and these details do not limit the present disclosure to necessarily implementing with the above specific details.

Claims

1. A mass transfer method, characterized in that, Including steps: S10 provides a first growth substrate, on which there are a plurality of first LED chips, and the electrodes of the first LED chips face away from the first growth substrate; S11 provides a first temporary substrate, on which an adhesive is provided, and the electrodes of the first LED chips are adhered to the first adhesive layer of the first temporary substrate, and then the first growth substrate is peeled off; S12 coats a photosensitive resin on the first temporary substrate provided with the first LED chips to form a first photosensitive resin layer, and the thickness H1 of the first photosensitive resin layer is greater than the height h1 of the first LED chips, that is, H1>h1; S13 covers a second temporary substrate on the photosensitive resin layer, and the second temporary substrate is made of a light-transmitting material; Provide a patterned mask to block the light rays directed at the first LED chips that do not need to be transferred, expose the corresponding part of the first photosensitive resin layer of the first LED chips to be transferred to cure it, and remove the unexposed first photosensitive resin layer through a developer, and the remaining photosensitive resin layer serves as the first transfer head; S14 selectively peels off the first LED chips to be transferred from the adhesive layer by laser peeling, so that the first LED chips are adhered to the second temporary substrate through the first transfer head; S15 moves the second temporary substrate, transfers the LED chips on the second temporary substrate to the display backplane, dissolves the transfer head through a stripping solution to separate the LED chips from the second temporary substrate, and completes the transfer of the LED chips; After step S15, the following steps are also executed: Provide a second growth substrate, on which there are a plurality of second LED chips, and the electrodes of the second LED chips face away from the second growth substrate; Provide a third temporary substrate, on which an adhesive is provided, and the electrodes of the second LED chips are adhered to the second adhesive layer of the third temporary substrate, and then the second growth substrate is peeled off; Coat a photosensitive resin on the third temporary substrate provided with the second LED chips to form a second photosensitive resin layer, and the thickness H2 of the second photosensitive resin layer is greater than the height h2 of the second LED chips, that is, H2>h2. If the height h2 of the second LED chips is not equal to the height h1 of the first LED chips, then the preset height of the second photosensitive resin layer covering the second LED chips is H2, satisfying the following condition: H2 - h2>|h2 - h1|; Cover a fourth temporary substrate on the second photosensitive resin layer, and the fourth temporary substrate is made of a light-transmitting material; Provide a patterned mask to block the light rays directed at the second LED chips that do not need to be transferred, expose the corresponding part of the second photosensitive resin layer of the second LED chips to be transferred to cure it, and remove the unexposed second photosensitive resin layer through a developer, and the remaining second photosensitive resin layer serves as the second transfer head; Selectively peel the second LED chip to be transferred from the adhesive layer by laser peeling, so that the second LED chip adheres to the fourth temporary substrate through the second transfer head; Move the fourth temporary substrate, transfer the LED chip on the fourth temporary substrate to the display backplane, dissolve the second transfer head with a stripping solution, and separate the LED chip from the fourth temporary substrate to complete the transfer of the second LED chip.

2. The mass transfer method according to claim 1, characterized in that, The method further includes: Provide a third growth substrate with a plurality of third LED chips thereon, and the electrodes of the third LED chips face away from the third growth substrate; Provide a fifth temporary substrate with an adhesive provided thereon, adhere the electrodes of the third LED chips to the third adhesive layer of the fifth temporary substrate, and peel off the third growth substrate; Coat a photosensitive resin on the fifth temporary substrate provided with the third LED chips to form a third photosensitive resin layer, and the thickness H3 of the third photosensitive resin layer is greater than the height h3 of the third LED chip, that is, H3>h3. If the height h3 of the third LED chip, the height h2 of the second LED chip, and the height h1 of the first LED chip are not equal to each other, then the preset height of the third photosensitive resin layer covering the third LED chip is H3, satisfying the following conditions: H3 - h3 > |h3 - h1| and H3 - h3 > |h3 - h2|; Cover a sixth temporary substrate on the third photosensitive resin layer, and the sixth temporary substrate is made of a light-transmitting material; Provide a patterned mask to block the light incident on the third LED chips that do not need to be transferred, expose the corresponding part of the third photosensitive resin layer of the third LED chips to be transferred to cure it, and remove the unexposed third photosensitive resin layer with a developer, and the remaining third photosensitive resin layer serves as the third transfer head; Selectively peel the third LED chip to be transferred from the adhesive layer by laser peeling, so that the third LED chip adheres to the sixth temporary substrate through the third transfer head; Move the sixth temporary substrate, transfer the LED chip on the sixth temporary substrate to the display backplane, dissolve the third transfer head with a stripping solution, and separate the LED chip from the sixth temporary substrate to complete the transfer of the third LED chip.

3. A mass transfer method, characterized in that, Including the steps: S10 Provide a first growth substrate with a plurality of first LED chips thereon, and the electrodes of the first LED chips face away from the first growth substrate; S11 Provide a first temporary substrate with an adhesive provided thereon, adhere the electrodes of the first LED chips to the first adhesive layer of the first temporary substrate, and peel off the first growth substrate; S12 Coat a photosensitive resin on the first temporary substrate provided with the first LED chips to form a first photosensitive resin layer, and the thickness H1 of the first photosensitive resin layer is greater than the height h1 of the first LED chip, that is, H1>h1; S13 Cover a second temporary substrate on the photosensitive resin layer, and the second temporary substrate is made of a light-transmitting material; Provide a patterned mask to block the light rays directed at the first LED chips that do not need to be transferred, expose the corresponding part of the first photosensitive resin layer of the first LED chips to be transferred to cure it, and remove the unexposed first photosensitive resin layer through a developer. The remaining photosensitive resin layer serves as the first transfer head; S14 Selectively peel the first LED chips to be transferred from the adhesive layer by laser peeling, so that the first LED chips adhere to the second temporary substrate through the first transfer head; S15 Move the second temporary substrate to transfer the LED chips on the second temporary substrate to the display backplane, dissolve the transfer head through a stripping solution to separate the LED chips from the second temporary substrate, and complete the transfer of the LED chips; After step S14 and before step S15, there is also a step: S21 Provide a second growth substrate, on which a plurality of second LED chips are formed, and the height of the second LED chips is h2; S22 Provide a third temporary substrate, on which a second adhesive layer is formed, adhere the second LED chips to the third temporary substrate, and after removing the second growth substrate, coat a photosensitive resin material on the third temporary substrate provided with the second LED chips to form a second photosensitive resin layer with a thickness of H21, and satisfy: H21≥H1; S23 Form a plurality of first grooves corresponding to the first LED chips on the second photosensitive resin layer, and cover the second photosensitive resin layer with the second temporary substrate picking up a plurality of the first LED chips; S24 Provide a patterned mask to block the light rays directed at the second LED chips that do not need to be transferred, expose the corresponding part of the second photosensitive resin layer of the second LED chips to be transferred to cure it, and remove the unexposed second photosensitive resin layer through a developer. The remaining second photosensitive resin layer serves as the second transfer head; S25 Selectively peel the second LED chips to be transferred from the adhesive layer by laser peeling, so that the second LED chips adhere to the second temporary substrate through the second transfer head.

4. The massive transfer method according to claim 3, wherein, After step S25 and before step S15, there is also a step: S31 Provide a third growth substrate, on which a plurality of third LED chips are formed, and the height of the third LED chips is h3; S32 Provide a fourth temporary substrate, on which a third adhesive layer is formed, adhere the third LED chips to the fourth temporary substrate, and after removing the third growth substrate, coat a photosensitive resin material on the fourth temporary substrate provided with the third LED chips to form a third photosensitive resin layer with a thickness of H31, and satisfy: H31≥H2+h3; S33 Form a plurality of second grooves and third grooves corresponding to the first LED chips and the second LED chips on the third photosensitive resin layer, and cover the second temporary substrate pick-up with a plurality of the first LED chips and the second LED chips on the third photosensitive resin layer; S34 Provide a patterned mask to block the light rays directed at the third LED chips that do not need to be transferred, expose the corresponding part of the third photosensitive resin layer of the third LED chips to be transferred to cure it, and remove the unexposed third photosensitive resin layer through a developer. The remaining third photosensitive resin layer serves as the third transfer head; S35 Selectively peel the third LED chips to be transferred from the third adhesive layer by laser peeling, so that the third LED chips adhere to the second temporary substrate through the third transfer head.

5. The massive transfer method according to claim 4, wherein, The display backplane includes a plurality of first bosses and a plurality of second bosses, The first LED chips on the second temporary substrate are bonded to the first bosses, The second LED chips on the second temporary substrate are bonded to the second bosses.

6. The massive transfer method according to claim 5, wherein, The height of the first boss is H11, the height of the second boss is H22, and the following conditions are satisfied: H22≥h3, H11≥H22 + h2, H11 = H31 - H1 and H22 = H31 - H21.

7. The massive transfer method according to any one of claims 4 to 6, wherein, The method for forming the first groove and the second groove is exposure and development or etching.

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