Mass transfer method
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- CHONGQING KONKA PHOTOELECTRIC TECH RES INST CO LTD
- Filing Date
- 2021-09-13
- Publication Date
- 2026-07-03
Smart Images
Figure CN115810649B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of light-emitting diode (LED) chip transfer technology, and more particularly to a mass transfer method. Background Technology
[0002] Miniature light-emitting diode (LED) chips are an emerging display technology. Compared with conventional display technologies, miniature LED chips have the advantages of fast response speed, self-illumination, high contrast, long lifespan, and high photoelectric efficiency.
[0003] In the process of transferring multiple light-emitting diode (LED) chips from the growth substrate to the temporary substrate and then from the temporary substrate to the backplane, corresponding support structures need to be prepared. In the traditional transfer method, the LED chips are first transferred to the temporary substrate, and then the support structure is prepared on the temporary substrate. This can easily lead to inconsistent structural dimensions of the support structure during the preparation process, and the adhesion values of each LED chip can vary greatly, which will reduce the transfer yield of the LED chips.
[0004] Therefore, improving the transfer yield of LED chips is an urgent problem to be solved. Summary of the Invention
[0005] In view of the shortcomings of the prior art, the purpose of this application is to provide a mass transfer method, which aims to solve the technical problem of low transfer yield of light-emitting diode chips.
[0006] A mass transfer method comprising the steps of:
[0007] A temporary storage substrate is provided, the temporary storage substrate having a plurality of support structures arranged in an array.
[0008] An adhesive is applied to at least the first surface of each of the support structures to form an adhesive layer.
[0009] Multiple light-emitting diode (LED) chips on a substrate are bonded to the temporary storage substrate using the adhesive layer; wherein, after bonding, the two electrodes of the LED chips are respectively located on two adjacent support structures.
[0010] Remove the substrate.
[0011] Each LED chip temporarily stored on the temporary storage substrate is transferred to a backplane.
[0012] A support structure for supporting LED chips is pre-set on the temporary storage substrate. The structural dimensions of the support structure can be uniformly set. When each LED chip is bonded to the support structure, the difference in adhesion force between each LED chip and the support structure is small, which can improve the transfer yield of LED chips.
[0013] Optionally, before providing a temporary storage base, the following steps may be included:
[0014] A substrate is provided, the substrate including a second surface and a third surface disposed opposite to each other.
[0015] The second surface of the substrate is etched such that at least some of the support structures are retained to form the temporary substrate.
[0016] The process of forming the temporary substrate is simplified by directly etching the substrate.
[0017] Optionally, etching the second surface of the substrate includes the step of:
[0018] A photoresist layer is formed on the second surface of the substrate.
[0019] The photoresist layer is patterned to form a pattern in the photoresist layer.
[0020] The substrate is etched based on the pattern to form several support structures.
[0021] By forming patterns on the photoresist, it is easier to form individual support structures and control the size of each support structure during the formation process.
[0022] Optionally, before providing a temporary storage base, the following steps may be included:
[0023] A substrate is provided, the substrate including a second surface and a third surface disposed opposite to each other.
[0024] A silicon dioxide layer is formed on the second surface of the substrate.
[0025] The silicon dioxide layer is etched such that the retained portion of the silicon dioxide layer forms a plurality of the support structures, wherein the substrate and the plurality of the support structures form the temporary substrate.
[0026] By depositing a silicon dioxide layer on the substrate and etching the silicon dioxide layer to form several support structures, the etching of the silicon dioxide layer to form several support structures can be adapted to various etching processes, and the process cycle for etching to form several support structures is relatively short.
[0027] Optionally, the etching of the silicon dioxide layer includes the following steps:
[0028] A photoresist layer is formed on the surface of the silicon dioxide layer away from the substrate.
[0029] The photoresist layer is patterned to form a pattern in the photoresist layer.
[0030] The silicon dioxide layer is etched based on the pattern to form several of the support structures.
[0031] By forming patterns on the photoresist, it is easier to form individual support structures and control the size of each support structure during the formation process.
[0032] Optionally, the first surfaces of each of the support structures are flush, so that when the support structure is bonded to the light-emitting diode chip, each light-emitting diode chip can be temporarily stored flat on the temporary storage substrate, which also facilitates the bonding between the light-emitting diode chip and the support structure.
[0033] Optionally, the step of applying the adhesive at least on a first surface in each of the support structures to form an adhesive layer includes the step of:
[0034] Adhesive is filled between each of the support structures, and the adhesive covers the first surface of each of the support structures to form the adhesive layer; adhesive is directly filled on the temporary substrate until the adhesive covers each of the support structures, which facilitates the bonding of the support structures to the light-emitting diode chip.
[0035] The process of bonding multiple light-emitting diode chips on a substrate to a temporary storage substrate using the adhesive layer includes the following steps:
[0036] Each of the two electrodes of the light-emitting diode chip is respectively associated with two of the support structures;
[0037] The two electrodes of the light-emitting diode chip are embedded in the adhesive layer and respectively attached to the two support structures.
[0038] Optionally, after bonding the multiple light-emitting diode chips on the substrate to the temporary storage substrate via the adhesive layer, and before transferring each light-emitting diode chip temporarily stored on the temporary storage substrate to a backplane, the adhesive layer between adjacent support structures is removed, so that the adhesive layer between the electrodes of each light-emitting diode chip and each support structure is retained.
[0039] By removing the adhesive layer between adjacent support structures in the adhesive layer, the adhesive layer between adjacent support structures in the adhesive layer is prevented from affecting the adhesion between each LED chip and the temporary substrate.
[0040] Optionally, the individual light-emitting diode chips temporarily stored on the temporary storage substrate are transferred to a backplane, including the following steps:
[0041] Provide a transfer head;
[0042] The transfer head is bonded to each of the light-emitting diode chips temporarily stored in the temporary storage substrate;
[0043] The transfer head picks up each of the LED chips and transfers each LED chip to the backplane. Attached Figure Description
[0044] Figure 1 A flowchart illustrating the mass transfer method provided in an embodiment of this application;
[0045] Figure 2 for Figure 1 A structural diagram of one of the processes;
[0046] Figure 3 for Figure 1 A structural diagram of one of the processes;
[0047] Figure 4 for Figure 1 A structural diagram of one of the processes;
[0048] Figure 5 for Figure 1 A structural diagram of one of the processes;
[0049] Figure 6 for Figure 1 A structural diagram of one of the processes.
[0050] Explanation of reference numerals in the attached figures:
[0051] 10 - Substrate; 11 - Second surface; 12 - Third surface;
[0052] 20 - Photoresist layer;
[0053] 30-Silica layer;
[0054] 100 - Temporary storage substrate; 110 - Support structure; 111 - First surface;
[0055] 200 - Adhesive layer;
[0056] 300-substrate;
[0057] 400 - LED chip; 410 - Electrode;
[0058] 500-backplate;
[0059] 600-Transfer head. Detailed Implementation
[0060] To facilitate understanding of this application, a more complete description will be provided below with reference to the accompanying drawings. Preferred embodiments of this application are shown in the drawings. However, this application can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to provide a more thorough and complete understanding of the disclosure of this application.
[0061] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein in the specification of this application is for the purpose of describing particular embodiments only and is not intended to be limiting of this application.
[0062] Problems with Existing Solutions: Micro LED chips are an emerging display technology. Compared with conventional display technologies, micro LED chips have the advantages of fast response speed, self-illumination, high contrast, long lifespan, and high photoelectric efficiency.
[0063] During the process of transferring multiple LED chips from the growth substrate to the temporary substrate and then from the temporary substrate to the backplane, corresponding weakening structures are prepared. In the traditional transfer method, the LED chips are first transferred to the temporary substrate, and then the weakening structure is prepared on the temporary substrate. This can easily lead to inconsistent structural dimensions of the support structure during the preparation process, and the adhesion values of each LED chip can vary greatly, which will reduce the transfer yield of the LED chips.
[0064] Therefore, this application aims to provide a solution that can solve the above-mentioned technical problems, the details of which will be described in subsequent embodiments.
[0065] See Figure 1 This application provides a detailed description of a mass transfer method, which includes, but is not limited to, the following steps:
[0066] S1, A temporary storage substrate 100 is provided, the temporary storage substrate 100 having several arrayed support structures 110.
[0067] The light-emitting diode chip 400 is grown and formed on the substrate 300. After the light-emitting diode chip 400 is grown and formed on the substrate 300, the light-emitting diode chip 400 formed on the substrate 300 can be transferred. During the transfer process, please refer to [link to relevant documentation]. Figure 5 The light-emitting diode chip 400 can be transferred from the substrate 300 to the temporary substrate 100, and then transferred from the temporary substrate 100 to the backplane 500.
[0068] The LED chip 400 can be a Micro LED or Mini LED chip.
[0069] In the embodiments provided in this application, the temporary storage substrate 100 can be formed by directly etching the substrate 10, and the temporary storage substrate 100 is used to temporarily place multiple light-emitting diode chips 400 grown on the substrate 300.
[0070] Specifically, please see Figure 2 The temporary storage substrate 100 may include a connection structure and a plurality of support structures 110. The plurality of support structures 110 are arranged in an array on the connection structure. When the light-emitting diode chip 400 is temporarily stored in the temporary storage substrate 100, the support structures 110 support the light-emitting diode chip 400.
[0071] S2, an adhesive is applied to at least the first surface 111 of each of the support structures 110 to form an adhesive layer 200.
[0072] In the embodiments provided in this application, when the light-emitting diode chip 400 is supported by the support structure 110 in the temporary storage substrate 100, in order to enable the light-emitting diode chip 400 to be stably temporarily stored on the temporary storage substrate 100, an adhesive layer 200 is formed by coating the first surface 111 of each support structure 110 with adhesive. The light-emitting diode chip 400 can be bonded to the support structure 110 through the adhesive layer 200, so that the light-emitting diode chip 400 can be stably temporarily stored on the temporary storage substrate 100.
[0073] S3, a plurality of light-emitting diode chips 400 on the substrate 300 are bonded to the temporary storage substrate 100 through the adhesive layer 200; wherein, after bonding, the two electrodes 410 of the light-emitting diode chips 400 are respectively located on two adjacent support structures 110.
[0074] Please refer to the embodiments provided in this application. Figure 5 Each LED chip 400 has two electrodes 410. When the LED chip 400 is temporarily stored on the temporary storage substrate 100, the two electrodes 410 of each LED chip 400 are respectively located on two adjacent support structures 110. Each LED chip 400 is supported by two support structures 110. Specifically, the two electrodes 410 of each LED chip 400 are fixedly connected to the two support structures 110 through an adhesive layer 200, so that each LED chip 400 can be stably fixed on the temporary storage substrate 100.
[0075] S4, Remove the substrate 300.
[0076] In the embodiments provided in this application, the substrate 300 is first peeled off from the plurality of light-emitting diode chips 400 by laser, and then the substrate 300 is removed.
[0077] S5, the individual light-emitting diode chips 400 temporarily stored on the temporary storage substrate 100 are transferred to a backplate 500.
[0078] Please see Figure 6 After the substrate 300 is removed, each of the light-emitting diode chips 400 is fixed on the temporary storage substrate 100. In the embodiment provided in this application, each of the light-emitting diode chips 400 is adhered to the transfer head 600, and then the light-emitting diode chips 400 are separated from the temporary storage substrate 100. After that, the transfer head 600 transfers each of the light-emitting diode chips 400 that is adhered to it to the back plate 500.
[0079] In the embodiments provided in this application, a support structure 110 for supporting the light-emitting diode chip 400 is pre-set on the temporary storage substrate 100. The structural dimensions of the support structure 110 can be conveniently and uniformly set. When each light-emitting diode chip 400 is bonded to the support structure 110, the difference in adhesion force between each light-emitting diode chip 400 and the support structure 110 is small, which can improve the transfer yield of the light-emitting diode chip 400.
[0080] In the first possible implementation, please see Figure 3 Before providing a temporary storage substrate 100, the steps include:
[0081] A substrate 10 is provided, the substrate 10 including a second surface 11 and a third surface 12 disposed opposite to each other.
[0082] The second surface 11 of the substrate 10 is etched so that at least a plurality of the support structures 110 are retained to form the temporary substrate 100.
[0083] Generally, the substrate 10 is a silicon substrate, and the second surface 11 of the substrate 10 can be etched using a deep silicon etching device to form a plurality of support structures 110 of the same size. In the embodiments provided in this application, the plurality of support structures 110 are arranged in an array.
[0084] Specifically, the provided substrate 10 has a uniform thickness, and both the second surface 11 and the third surface 12 are flat. When the second surface 11 of the substrate 10 is etched using a deep silicon etching device, multiple grooves of the same depth are etched into the second surface 11 of the substrate 10. The retained portion has several support structures 110 and connecting structures of the same size. The upper surface of the connecting structure is the bottom surface of the multiple grooves. The several support structures 110 of the same size are arranged in an array on the connecting structure.
[0085] Before etching the second surface 11 of the substrate 10, the following steps are included:
[0086] A photoresist layer 20 is formed on the second surface 11 of the substrate 10;
[0087] The photoresist layer is patterned to form a pattern, and the substrate is etched according to the pattern to form a plurality of support structures 110.
[0088] In a first possible implementation, in order to etch multiple support structures 110 of uniform size, a pattern needs to be pre-constructed. When etching the substrate 10 to form several support structures 110, photoresist is spin-coated onto the second surface 11 of the substrate 10 to form the photoresist layer 20. A pattern is formed on the photoresist layer 20. When etching the substrate 10, the substrate 10 is etched according to the pattern to form several support structures 110. Then, the photoresist layer 20 on the support structures 110 is removed to form the temporary substrate 100.
[0089] For the second possible implementation, please refer to Figure 4 Before providing a temporary storage substrate 100, the steps include:
[0090] A substrate 10 is provided, the substrate 10 including a second surface 11 and a third surface 12 disposed opposite to each other;
[0091] A silicon dioxide layer 30 is formed on the second surface 11 of the substrate 10;
[0092] A portion of the silicon dioxide layer 30 is removed, such that the remaining portion of the silicon dioxide layer 30 forms a plurality of the support structures 110;
[0093] The substrate 10 and the plurality of the support structures 110 form the temporary storage substrate 100.
[0094] Specifically, in order to simplify the forming process of the plurality of support structures 110 in the temporary substrate 100, a silicon dioxide layer 30 can be formed on the second surface 11 of the substrate 10, and then the silicon dioxide layer 30 can be formed by wet etching to form the plurality of support structures 110. Compared with forming the plurality of support structures 110 by etching the second surface 11 of the substrate 10 using a deep silicon etching device, the cycle of forming the support structures 110 can be greatly shortened by forming the silicon dioxide layer 30 by wet etching.
[0095] In the embodiments provided in this application, a plurality of the support structures 110 are arranged in an array on the substrate 10.
[0096] In a second possible implementation, before removing a portion of the silicon dioxide layer 30 so that the remaining portion of the silicon dioxide layer 30 forms the plurality of the support structures 110, the following steps are included:
[0097] A photoresist layer 20 is formed on the surface of the silicon dioxide layer 30 away from the substrate 10;
[0098] The photoresist layer 20 is patterned to form a pattern, and the silicon dioxide layer is etched according to the pattern to form a plurality of the support structures 110. The plurality of support structures 110 and the substrate 10 form the temporary substrate.
[0099] Specifically, in order to etch multiple support structures 110 of the same size array, a pattern needs to be constructed in advance. When etching the silicon dioxide layer 30 to form several support structures 110, photoresist is spin-coated on the surface of the silicon dioxide layer 30 away from the substrate 10 to form the photoresist layer 20, and a pattern is formed on the photoresist layer 20. When etching the substrate 10, the silicon dioxide layer 30 is etched according to the pattern to form several support structures 110. Then the photoresist layer 20 on the support structures 110 is removed to form the temporary substrate 100.
[0100] In the embodiments provided in this application, the support structure 110 is used to support the light-emitting diode chip 400. Specifically, the two electrodes 410 of each light-emitting diode chip 400 are respectively disposed on the two support structures 110. In order to ensure the stability of the light-emitting diode chip 400 disposed on the two support structures 110, the first surface 111 of each support structure 110 is flush, and the first plane of all support structures 110 is on the same plane, so that all light-emitting diode chips 400 are stably disposed on the temporary substrate 100.
[0101] The step of applying adhesive to at least the first surface 111 of each of the support structures 110 to form an adhesive layer 200 includes the following steps:
[0102] Please see Figure 5 Adhesive is filled between each of the support structures 110, and adhesive is applied to the first surface 111 of each of the support structures 110 to form the adhesive layer 200.
[0103] In the embodiments provided in this application, the number of light-emitting diode chips 400 grown on the substrate 300 is enormous. A plurality of support structures 110 in the temporary storage substrate 100 are used to support the plurality of light-emitting diode chips 400. The number of support structures 110 is also enormous. To improve the efficiency of placing the adhesive on each support structure 110, the adhesive can be directly laid on the temporary storage substrate 100, filling the spaces between connected support structures 110, and covering each support structure 110 to form an adhesive layer 200. Generally, the distance between the surface of the adhesive layer 200 away from the temporary storage substrate 100 and the first surface 111 of the support structure 110 is less than 5 μm. It is understood that the distance between the surface of the adhesive layer 200 away from the temporary storage substrate 100 and the first surface 111 of the support structure 110 can also be other ranges.
[0104] The process of bonding multiple light-emitting diode chips 400 on the substrate 300 to the temporary storage substrate 100 via the adhesive layer 200 includes the following steps:
[0105] Each of the two electrodes 410 of the light-emitting diode chip is respectively associated with two of the two support structures 110;
[0106] The two electrodes 410 of the light-emitting diode chip 400 are embedded in the adhesive layer 200 and respectively attached to the two support structures 110.
[0107] In the embodiments provided in this application, each light-emitting diode chip 400 has two electrodes 410, which are spaced apart. When each light-emitting diode chip 400 is temporarily stored on the temporary storage substrate 100, the two electrodes 410 of each light-emitting diode chip 400 are bonded to two adjacent support structures 110 respectively. After the adhesive layer 200 is cured, there is a certain adhesive force between the light-emitting diode chip 400 and the support structure 110 bonded by the adhesive layer 200. The electrode 410 in each light-emitting diode chip 400 formed on the substrate 300 has almost the same size, and the size and structure of each support structure 110 in the temporary storage substrate 100 are almost the same. Therefore, the difference in the adhesive force between each light-emitting diode chip 400 and the temporary storage substrate 100 is small (wherein, the magnitude of the adhesive force between the light-emitting diode chip 400 and the temporary storage substrate 100 is positively correlated with the contact area between the light-emitting diode chip 400 and the temporary storage substrate 100).
[0108] After bonding the plurality of light-emitting diode chips 400 on the substrate 300 to the temporary storage substrate 100 via the adhesive layer 200, and before transferring each light-emitting diode chip 400 temporarily stored on the temporary storage substrate 100 to a backplate 500, the adhesive layer 200 between adjacent support structures 110 is removed, so that the adhesive layer 200 between the electrode 410 of each light-emitting diode chip 400 and each support structure 110 is retained.
[0109] In the embodiments provided in this application, in order to facilitate the smooth transfer of the light-emitting diode chip 400 onto the back plate 500, the portion of the adhesive layer 200 that does not directly connect the light-emitting diode chip 400 and the support structure 110 needs to be removed during the transfer of the light-emitting diode chip 400. This is to avoid the presence of the portion of the adhesive layer 200 that does not directly connect the light-emitting diode chip 400 and the support structure 110 affecting the adhesion between the light-emitting diode chip 400 and the temporary substrate 100.
[0110] Specifically, by dry etching to remove the adhesive layer 200 between adjacent support structures 110, only the adhesive layer that bonds the LED chip 400 and the support structure 110 together is preserved. This results in a smaller difference in the adhesion force between each LED chip 400 and the temporary substrate 100, which can improve the transfer yield of the LED chip 400 when transferring each LED chip 400.
[0111] The process of transferring each light-emitting diode chip 400 temporarily stored on the temporary storage substrate 100 onto a backplane 500 includes the following steps:
[0112] Provide a 600 transfer head.
[0113] The transfer head 600 is bonded to each of the light-emitting diode chips 400 temporarily stored on the temporary storage substrate 100.
[0114] The transfer head 600 picks up each of the light-emitting diode chips 400 and transfers each of the light-emitting diode chips 400 onto the back plate 500.
[0115] In the embodiments provided in this application, a transfer head 600 transfers a light-emitting diode (LED) chip 400 located on a backplate 500 onto the backplate 500. Specifically, the substrate 300 and the LED chip 400 are first irradiated with a laser to peel the LED chip 400 from the substrate 300. After removing the substrate 300, the transfer head 600 temporarily holds multiple LED chips 400 on a temporary storage substrate 100. The transfer head 600 picks up each LED chip 400, separating the multiple LED chips 400 from the temporary storage substrate 100. The transfer head 600 carries each LED chip 400 and transfers each LED chip 400 onto the backplate 500.
[0116] It should be understood that the application of the present invention is not limited to the examples above. Those skilled in the art can make improvements or modifications based on the above description, and all such improvements and modifications should fall within the protection scope of the appended claims.
Claims
1. A mass transfer method, characterized in that, Including the following steps: A temporary storage substrate is provided, the temporary storage substrate having a plurality of support structures arranged in an array; An adhesive is applied at least on the first surface of each of the support structures to form an adhesive layer; Multiple light-emitting diode (LED) chips on a substrate are bonded to the temporary storage substrate using the adhesive layer; wherein, after bonding, the two electrodes of the LED chips are respectively located on two adjacent support structures; Remove the substrate; Each LED chip temporarily stored on the temporary storage substrate is transferred to a backplane.
2. The mass transfer method as described in claim 1, characterized in that, Before providing a temporary storage base, the following steps are included: A substrate is provided, the substrate including a second surface and a third surface disposed opposite to each other; The second surface of the substrate is etched such that at least some of the support structures are retained to form the temporary substrate.
3. The mass transfer method as described in claim 2, characterized in that, The etching of the second surface of the substrate includes the following steps: A photoresist layer is formed on the second surface of the substrate; Pattern the photoresist layer to form a pattern in the photoresist layer; The substrate is etched based on the pattern to form several of the support structures.
4. The mass transfer method as described in claim 1, characterized in that, Before providing a temporary storage base, the following steps are included: A substrate is provided, the substrate including a second surface and a third surface disposed opposite to each other; A silicon dioxide layer is formed on the second surface of the substrate; The silicon dioxide layer is etched such that the retained portion of the silicon dioxide layer forms a plurality of the support structures, wherein the substrate and the plurality of the support structures form the temporary substrate.
5. The mass transfer method as described in claim 4, characterized in that, The etching of the silicon dioxide layer includes the following steps: A photoresist layer is formed on the surface of the silicon dioxide layer away from the substrate; Pattern the photoresist layer to form a pattern in the photoresist layer; The silicon dioxide layer is etched based on the pattern to form several of the support structures.
6. The mass transfer method as described in claim 1, characterized in that, The first surfaces of each of the aforementioned support structures are flush.
7. The mass transfer method as described in claim 6, characterized in that, The step of applying adhesive to at least the first surface of each of the support structures to form an adhesive layer includes the following steps: Adhesive is filled between the various support structures, and adhesive is applied to the first surface of each support structure to form the adhesive layer.
8. The mass transfer method as described in claim 7, characterized in that, The method of bonding multiple light-emitting diode chips on a substrate to the temporary storage substrate via the adhesive layer includes the following steps: Each of the two electrodes of the light-emitting diode chip is respectively associated with two of the support structures; The two electrodes of the light-emitting diode chip are embedded in the adhesive layer and respectively attached to the two support structures.
9. The mass transfer method as described in claim 8, characterized in that, After bonding multiple light-emitting diode (LED) chips on the substrate to the temporary storage substrate using the adhesive layer, and before transferring each LED chip temporarily stored on the temporary storage substrate to a backplane, the adhesive layer between adjacent support structures is removed, so that the adhesive layer between the electrodes of each LED chip and each support structure is retained.
10. The mass transfer method according to any one of claims 1-9, characterized in that, The process of transferring each light-emitting diode chip temporarily stored on the temporary storage substrate to a backplane includes the following steps: Provide a transfer head; The transfer head is bonded to each of the light-emitting diode chips temporarily stored in the temporary storage substrate; The transfer head picks up each of the LED chips and transfers each LED chip to the backplane.