Driving backplane and bonding method

Abstract

The application discloses a kind of driving backboard and bonding method, belong to display technical field.The driving backboard provided in the application includes backboard main body and the deformable layer being arranged to the first surface of backboard main body.The first surface of backboard main body has a plurality of bonding areas for bonding with LED chip, and the bonding area coincides with the orthographic projection of LED chip on the first surface.The deformable layer is provided with a plurality of first openings, one first opening corresponds to one bonding area, the edge of the orthographic projection of first opening on the first surface is located at the periphery of the corresponding bonding area, and the surface of deformable layer deviating from backboard main body exceeds the surface of LED chip deviating from backboard main body.When LED chip is transferred to bonding area, deformable layer deforms, the size of first opening becomes smaller, and the orthographic projection of at least part of first opening after becoming smaller on the first surface is located within bonding area.The driving backboard of the application can improve the transfer yield of mass transfer process.

Description

Technical Field

[0001] This application relates to the field of display technology, and in particular to a driving backplane and bonding method. Background Technology

[0002] Micro-LED display technology boasts advantages such as high brightness, high luminous efficiency, low power consumption, and high stability, making it a research hotspot in the pursuit of next-generation display technologies. However, with technological advancements, the size of Micro-LED chips continues to shrink, leading to a continuous increase in the number of Micro-LED chips that need to be mass-transferred onto the driver backplane, thus posing increasingly significant challenges to mass transfer technology.

[0003] The inventors of this application have discovered in their long-term research on mass transfer that in existing mass transfer processes, the alignment accuracy between the Micro-LED chip and the driving substrate is low. The Micro-LED chip is prone to rotational misalignment during the bonding process with the driving substrate, and the Micro-LED chip often fails to transfer from the transfer head to the driving substrate, resulting in a low transfer yield in the mass transfer process. Summary of the Invention

[0004] The main technical problem addressed by this application is to provide a driving backplane and bonding method that can improve the transfer yield of the mass transfer process.

[0005] To solve the above-mentioned technical problems, one technical solution adopted in this application is: to provide a drive backplane, comprising:

[0006] A backplate body, wherein the first surface of the backplate body has a plurality of bonding areas, the bonding areas being used for bonding with an LED chip;

[0007] A deformable layer is disposed on the first surface. The deformable layer has a plurality of through first openings, one first opening corresponding to one bonding region. The edge of the orthographic projection of the first opening on the first surface is located outside the corresponding bonding region. The distance from the surface of the deformable layer away from the backplate body to the first surface is greater than the thickness of the LED chip.

[0008] When the LED chip is bonded to the backplane body, the deformable layer deforms so that at least a portion of the first opening's orthogonal projection on the first surface lies within the bonding area.

[0009] Optionally, when the LED chip is bonded to the backplane body, after the deformable layer is deformed, the orthographic projection of all the first openings on the first surface is located within the corresponding bonding area.

[0010] Optionally, all the first openings are divided into first sub-holes and second sub-holes, the size of the first sub-hole being smaller than the size of the second sub-hole; wherein, when the LED chip is bonded to the backplane body, after the deformable layer is deformed, the orthographic projection of the first sub-hole on the first surface is located within the corresponding bonding area, and the orthographic projection of the second sub-hole on the first surface covers the corresponding bonding area.

[0011] Optionally, the drive backplane further includes:

[0012] A sacrificial layer is stacked between the backplate body and the deformable layer; the sacrificial layer is provided with a plurality of through second openings, the second openings, the first openings, and the bonding regions correspond one-to-one, and the edge of the orthographic projection of the second opening on the first surface is located outside the corresponding bonding region;

[0013] Preferably, the deformable layer can be removed along with the sacrificial layer.

[0014] Optionally, the orthographic projection of the first opening onto the first surface covers the orthographic projection of the corresponding second opening onto the first surface.

[0015] Optionally, the depth of the second opening is greater than or equal to the thickness of the LED chip;

[0016] Preferably, the inner wall shape of the second opening matches the outer surface shape of the LED chip.

[0017] To solve the above-mentioned technical problems, another technical solution adopted in this application is: to provide a bonding method, including:

[0018] Provide the drive backplane described in the above technical solution;

[0019] The transfer head is positioned opposite the bonding region, and the LED chip attached to the transfer head is brought into contact with the bonding region; wherein the edge of the orthographic projection of the LED chip onto the plane of the transfer head is located on the periphery of the corresponding region of the transfer head.

[0020] The transfer head and / or the drive backplate are squeezed to deform the deformable layer; wherein, after the deformable layer is deformed, at least a portion of the deformable layer around the first opening extends to the surface of the corresponding LED chip away from the bonding region;

[0021] Move the transfer head away from the drive backplate, and leave the LED chip corresponding to at least a portion of the first opening on the drive backplate.

[0022] Optionally, the first adhesion force between the LED chip and the transfer head is less than or equal to the second adhesion force between the LED chip and the bonding region; the step of squeezing the transfer head and / or the driving backplate to deform the deformable layer includes:

[0023] The transfer head and / or the drive backplate are squeezed; wherein, after the deformable layer is deformed, all of the deformable layer around the first opening extends to the surface of the corresponding LED chip away from the bonding region.

[0024] Optionally, all the first openings are divided into first sub-holes and second sub-holes, the size of the first sub-hole is smaller than the size of the second sub-hole, and the first adhesion force between the LED chip and the transfer head is greater than the second adhesion force between the LED chip and the bonding area; the step of squeezing the transfer head and / or the driving backplate to deform the deformable layer includes:

[0025] The transfer head and / or the drive backplate are squeezed; wherein, after the deformable layer is deformed, only the deformable layer around the first sub-hole extends to the surface of the corresponding LED chip away from the bonding area, and in the bonding direction, the sum of the force exerted by the deformable layer around the first sub-hole on the LED chip and the second bonding force is greater than the first bonding force.

[0026] Optionally, after the step of moving the transfer head away from the drive backplate, the method further includes:

[0027] Remove the deformable layer.

[0028] The beneficial effects of this application are as follows: The driving backplane provided by this application includes a backplane body and a deformable layer disposed on the first surface of the backplane body. The first surface of the backplane body has multiple bonding areas for bonding with LED chips. The deformable layer is provided with multiple through-holes, each corresponding to a bonding area. The edge of the orthographic projection of the first hole on the first surface is located outside the corresponding bonding area, and the distance from the surface of the deformable layer away from the backplane body to the first surface is greater than the thickness of the LED chip. When bonding the LED chip to the backplane body, the deformable layer deforms, so that at least a portion of the orthographic projection of the first hole on the first surface is located within the bonding area. It can be seen that after the deformable layer around the at least portion of the first hole deforms, it extends to the back side of the corresponding LED chip, applying force to the LED chip from the back side, making it easier for the LED chip to separate from the transfer head and to bond with the bonding area. Moreover, the first hole also acts as a limiting element for the LED chip, making it easier to align the LED chip with the bonding area and reducing the probability of LED chip rotational misalignment during the bonding process. Therefore, the drive backplane of this application can improve the transfer yield of the mass transfer process. Attached Figure Description

[0029] To more clearly illustrate the technical solutions in the embodiments of this application, the drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort. Among them:

[0030] Figure 1 This is a schematic diagram of the structure of one embodiment of the drive backplane of this application;

[0031] Figure 2 for Figure 1 A schematic diagram of the structure in which the deformable layer undergoes deformation;

[0032] Figure 3 This is a schematic diagram of another embodiment of the drive backplane of this application;

[0033] Figure 4 for Figure 3 A schematic diagram of the structure in which the deformable layer undergoes deformation;

[0034] Figure 5 This is a schematic diagram of another embodiment of the drive backplane of this application;

[0035] Figure 6 This is a schematic diagram of another embodiment of the drive backplane of this application;

[0036] Figure 7 for Figure 5 A schematic diagram of the structure in which the deformable layer undergoes deformation;

[0037] Figure 8 This is a schematic diagram of another embodiment of the drive backplane of this application;

[0038] Figure 9 for Figure 8 A schematic diagram of the structure in which the deformable layer undergoes deformation;

[0039] Figure 10 This is a flowchart illustrating one embodiment of the bonding method of this application;

[0040] Figure 11 for Figure 10 A schematic diagram of the structure corresponding to the implementation method of step S12;

[0041] Figure 12 for Figure 11 A schematic diagram of the structure corresponding to the implementation method of step S14 in the middle section;

[0042] Figure 13 for Figure 11A schematic diagram of the structure corresponding to another embodiment of step S14;

[0043] Figure 14 This is a structural schematic diagram of one embodiment of the bonding method. Detailed Implementation

[0044] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of them. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0045] Please see Figure 1 , Figure 1 This is a schematic diagram of the structure of one embodiment of the drive backplate of this application. The drive backplate includes a backplate body 11 and a deformable layer 12. The material of the deformable layer 12 can be OCA adhesive, acrylic adhesive, etc.

[0046] The backplate body 11 has a plurality of bonding regions 110 on its first surface. The bonding regions 110 are used to bond with LED chips (not shown). Specifically, the bonding regions 110 are provided with a plurality of bonding electrodes for forming conductive connections with the pads of the LED chips. The bonding regions 110 coincide with the orthographic projection of the LED chips to be bonded on the first surface. Figure 1 The diagram illustrates the case where two bonding electrodes (not shown) are set in each bonding region 110.

[0047] The deformable layer 12 is disposed on the first surface of the backplate body 11. The deformable layer 12 has multiple through first openings 120, each corresponding to a bonding region 110. The edge of the orthographic projection of the first opening 120 on the first surface is located outside the corresponding bonding region 110, meaning that the bonding region 110 and the bonding electrode are completely exposed through the corresponding first opening 120, and the LED chip can be placed inside the first opening 120. Furthermore, the distance from the surface of the deformable layer 12 away from the backplate body 11 to the first surface is greater than the thickness of the LED chip to be bonded. That is, after bonding with the LED chip, the surface of the deformable layer 12 away from the backplate body 11 extends beyond the surface of the LED chip away from the backplate body 11. In other words, when the LED chip is placed inside the first opening 120, a portion of the deformable layer 12 protrudes above the corresponding back surface of the LED chip (the surface of the LED chip away from the backplate body 11).

[0048] Please combine Figure 1 See Figure 2 , Figure 2 for Figure 1A schematic diagram of the deformable layer undergoing deformation. When bonding the LED chip 500 to the backplane body 11, the LED chip 500 is first placed in the first opening 120 using a transfer substrate. One side of the transfer substrate has multiple transfer heads 600, with each transfer head 600 corresponding to one LED chip 500. Then, the deformable layer 12 is deformed, reducing the size of the first opening 120. Specifically, the size of the first opening 120 refers to the volume of the accommodating space within the first opening 120. Furthermore, at least a portion of the reduced-size first opening 120 has its orthographic projection on the first surface located within the bonding region 110. That is, after the size reduction, it is possible that the orthographic projection of some of the first openings 120 on the first surface is located within the bonding region 110, or it is possible that the orthographic projection of all the first openings 120 on the first surface is located within the bonding region 110. This embodiment uses the case where the orthographic projection of all the reduced-size first openings 120 on the first surface is located within the bonding region 110 as an example to illustrate the bonding process between the driving backplane and the LED chip 500 in this application.

[0049] In this embodiment, all first openings 120 are preferably of the same size. After the deformable layer 12 deforms, the deformable layer 12 around the first opening 120 extends toward the center of the first opening 120, making the size of the first opening 120 smaller. Specifically, the deformable layer 12 located below the back surface of the LED chip 500 extends to abut against the side surface of the LED chip 500, and the deformable layer 12 located above the back surface of the LED chip 500 extends to the back surface of the LED chip 500, so that the orthographic projection of the first opening 120 on the first surface is located within the bonding region 110.

[0050] During the subsequent separation of the LED chip 500 from the transfer head 600, the deformable layer 12 extending to the back of the LED chip 500 can apply force to the LED chip 500 from the back, making it easier for the LED chip 500 to separate from the transfer head 600 and to bond to the bonding region 110. Furthermore, the first opening 120 also acts as a limiting element for the LED chip 500, making it easier to align the LED chip 500 with the bonding region 110 and reducing the probability of rotational misalignment of the LED chip 500 during bonding. Therefore, the driving backplate provided in this embodiment can improve the transfer yield in mass transfer processes.

[0051] In one implementation, please refer to Figure 3 , Figure 3This is a schematic diagram of another embodiment of the driving backplane of this application. Similar to the above embodiment, the driving backplane in this embodiment includes a backplane body 21 and a deformable layer 22. The deformable layer 22 can be made of OCA adhesive, acrylic adhesive, etc. The first surface of the backplane body 21 has a plurality of bonding areas 210 for bonding with LED chips (not shown), and the bonding areas 210 coincide with the orthographic projection of the LED chip to be bonded on the first surface. A deformable layer 22 is disposed on the first surface of the backplate body 21. The deformable layer 22 is provided with a plurality of through first openings 220. Each first opening 220 corresponds to a bonding region 210. The edge of the orthographic projection of the first opening 220 on the first surface is located outside the corresponding bonding region 210. The distance from the surface of the deformable layer 22 away from the backplate body 21 to the first surface is greater than the thickness of the LED chip to be bonded. That is, after bonding with the LED chip, the surface of the deformable layer 22 away from the backplate body 21 exceeds the surface of the LED chip away from the backplate body 21.

[0052] Please combine Figure 3 See Figure 4 , Figure 4 for Figure 3 A schematic diagram of the deformable layer undergoing deformation. When bonding the LED chip 500 to the backplane body 21, the transfer head 600 first places the LED chip 500 into the first opening 220, and then the deformable layer 22 deforms, reducing the size of the first opening 220. At least a portion of the reduced-size first opening 220 has its orthographic projection on the first surface located within the bonding region 210. This embodiment uses the case where a portion of the first opening 220 has its orthographic projection on the first surface located within the bonding region 210 as an example to illustrate the bonding process between the driving backplane and the LED chip 500 in this application.

[0053] Specifically, all first openings 220 are divided into first sub-holes 220a and second sub-holes 220b, with the size of the first sub-hole 220a being smaller than the size of the second sub-hole 220b. When the deformable layer 22 deforms, the orthographic projection of the first sub-hole 220a onto the first surface lies within the corresponding bonding region 210, and the orthographic projection of the second sub-hole 220b onto the first surface covers the corresponding bonding region 210.

[0054] from Figure 4 As can be seen, after the deformable layer 22 deforms, the deformable layers 22 around the first sub-hole 220a and the second sub-hole 220b both extend toward the center of the hole, making the size of the first sub-hole 220a and the second sub-hole 220b smaller.

[0055] In this configuration, around the first sub-via 220a, the deformable layer 22 located below the back surface of the LED chip 500 extends to abut against the side surface of the LED chip 500, while the deformable layer 22 located above the back surface of the LED chip 500 extends to the back surface of the LED chip 500, such that the orthographic projection of the first sub-via 220a on the first surface lies within the bonding region 210. Around the second sub-via 220b, the extended deformable layer 22 still does not contact the LED chip 500, such that the orthographic projection of the second sub-via 220b on the first surface covers the corresponding bonding region 210.

[0056] During the subsequent separation of the LED chip 500 from the transfer head 600, the deformable layer 22 extending from the first sub-hole 220a to the back of the LED chip 500 can apply force to the LED chip 500 from the back, making it easier for the LED chip 500 to separate from the transfer head 600 and to bond to the bonding region 210. The deformable layer 22 around the second sub-hole 220b cannot apply force to the LED chip 500. If the adhesion force between the LED chip 500 and the transfer head 600 is pre-set to be greater than the adhesion force between the LED chip 500 and the bonding region 210, the LED chip 500 corresponding to the second sub-hole 220b will not separate from the transfer head 600. This allows the driving backplane provided in this embodiment to achieve selective bonding of LED chips. By setting the distribution of the first sub-hole 220a and the second sub-hole 220b in the first opening 220, the LED chip can be bonded to a pre-set portion of the bonding region 210 on the driving backplane, expanding the functionality and application scenarios of the driving backplane in this application.

[0057] Furthermore, the first opening 220 also serves to limit the LED chip 500, making it easier to align the LED chip 500 with the bonding area 210 and reducing the probability of rotational misalignment of the LED chip 500 during the bonding process. Therefore, the driving backplate provided in this embodiment can also improve the transfer yield of the mass transfer process.

[0058] In one implementation, please refer to Figure 5 , Figure 5 This is a schematic diagram of another embodiment of the driving backplane of this application. Compared with the above embodiment, in this embodiment, the driving backplane further includes a sacrificial layer 33. That is, the driving backplane includes a backplane body 31, a deformable layer 32, and a sacrificial layer 33. The deformable layer 32 can be made of OCA adhesive, acrylic adhesive, etc., and the sacrificial layer 33 can be made of photoresist, etc.

[0059] The backplate body 31 has a first surface with multiple bonding regions 310 for bonding with LED chips (not shown). The bonding regions 310 coincide with the orthographic projection of the LED chip to be bonded on the first surface. A deformable layer 32 is disposed on the first surface of the backplate body 31. The deformable layer 32 has multiple through first openings 320. Each first opening 320 corresponds to a bonding region 310. The edge of the orthographic projection of the first opening 320 on the first surface is located outside the corresponding bonding region 310. The distance from the surface of the deformable layer 32 away from the backplate body 31 to the first surface is greater than the thickness of the LED chip to be bonded. That is, after bonding with the LED chip, the surface of the deformable layer 32 away from the backplate body 31 extends beyond the surface of the LED chip away from the backplate body 31.

[0060] The sacrificial layer 33 is stacked between the backplate body 31 and the deformable layer 32. The sacrificial layer 33 is provided with a plurality of through second openings 330. The second openings 330, the first openings 320, and the bonding regions 310 correspond one-to-one. The edge of the orthographic projection of the second opening 330 on the first surface is located outside the corresponding bonding region 310. That is, the bonding region 310 is completely exposed from the corresponding first openings 320 and second openings 330. The LED chip can be placed in the space formed by the connection of the first openings 320 and the second openings 330.

[0061] Preferably, the orthographic projection of the first opening 320 on the first surface covers the orthographic projection of the corresponding second opening 330 on the first surface, that is, the orthographic projection of the first opening 320 on the first surface coincides with the orthographic projection of the corresponding second opening 330 on the first surface, or the orthographic projection of the second opening 330 on the first surface falls within the orthographic projection of the corresponding first opening 320 on the first surface. Figure 5 Draw the overlapping cases.

[0062] Preferably, the inner wall shape of the second opening matches the outer surface shape of the LED chip; see [link to details]. Figure 6 , Figure 6 This is a schematic diagram of another embodiment of the drive backplane of this application, wherein the drive backplane is in Figure 5 Further optimization of the second opening based on the drive backplate shown. Figure 6 The labels of each structure in the middle and Figure 5 The same applies, and an LED chip 500 is drawn within one of the second openings 330 to illustrate the bonding situation. Of course, this optimization can also be combined with various embodiments in this application, without limitation... Figure 6 The above is the limit.

[0063] The pads on the surface of an LED chip typically protrude from its functional surface, giving its outer surface a stepped shape. In this embodiment, the inner wall shape of the second opening 330 is matched with the outer surface shape of the LED chip 500. Specifically, a step is provided on the side wall of the second opening 330, and a patterned opening is formed between the bonding electrodes on the bottom surface of the second opening 330. This can further reduce the probability of rotational misalignment of the LED chip 500 during the bonding process and improve the transfer yield.

[0064] Please combine Figure 5 See Figure 7 , Figure 7 for Figure 5 A schematic diagram of the deformable layer undergoing deformation. When bonding the LED chip 500 to the backplane body 31, the transfer head 600 first places the LED chip 500 into the first opening 320, and then the deformable layer 32 deforms, reducing the size of the first opening 320. At least a portion of the reduced-size first opening 320 has its orthographic projection on the first surface located within the bonding region 310. This embodiment uses the case where the orthographic projection of all the first openings 320 on the first surface is located within the bonding region 310 as an example to illustrate the bonding process between the driving backplane and the LED chip 500 in this application.

[0065] The depth of the second opening 330 is preferably greater than or equal to the thickness of the LED chip 500, so that the surface of the deformable layer 32 away from the back plate body 31 naturally exceeds the surface of the LED chip 500 away from the back plate body 31, and the sacrificial layer 33 provides support for the deformable layer 32. Figure 7 The diagram illustrates the case where the depth of the second opening 330 is equal to the thickness of the LED chip 500.

[0066] After the deformable layer 32 deforms, the deformable layer 32 around the first opening 320 extends toward the center of the first opening 320 and extends to the back of the LED chip 500, making the size of the first opening 320 smaller and making the orthographic projection of the first opening 320 on the first surface located within the bonding region 310.

[0067] During the subsequent separation of the LED chip 500 from the transfer head 600, the deformable layer 32 extending to the back of the LED chip 500 can apply force to the LED chip 500 from the back, making it easier for the LED chip 500 to separate from the transfer head 600 and to bond to the bonding region 310. Furthermore, the first opening 320 and the second opening 330 also limit the LED chip 500, making it easier to align the LED chip 500 with the bonding region 310 and reducing the probability of rotational misalignment of the LED chip 500 during bonding. Therefore, the driving backplate provided in this embodiment can improve the transfer yield of the mass transfer process.

[0068] In one implementation, please refer to Figure 8 , Figure 8 This is a schematic diagram of another embodiment of the drive backplane of this application, and... Figure 5 The implementation method shown is the same. In this embodiment, the driving backplane includes a backplane body 41, a deformable layer 42, and a sacrificial layer 43. The deformable layer 42 can be made of OCA adhesive, acrylic adhesive, etc., and the sacrificial layer 43 can be made of photoresist, etc.

[0069] The backplate body 41 has a first surface with multiple bonding regions 410 for bonding with LED chips (not shown). The bonding regions 410 coincide with the orthographic projection of the LED chip to be bonded on the first surface. A deformable layer 42 is disposed on the first surface of the backplate body 41. The deformable layer 42 has multiple through first openings 420. Each first opening 420 corresponds to a bonding region 410. The edge of the orthographic projection of the first opening 420 on the first surface is located outside the corresponding bonding region 410. The distance from the surface of the deformable layer 42 away from the backplate body 41 to the first surface is greater than the thickness of the LED chip to be bonded. That is, after bonding with the LED chip, the surface of the deformable layer 42 away from the backplate body 41 extends beyond the surface of the LED chip away from the backplate body 41.

[0070] The sacrificial layer 43 is stacked between the backplate body 41 and the deformable layer 42. The sacrificial layer 43 is provided with a plurality of through second openings 430. The second openings 430, the first openings 420, and the bonding regions 410 correspond one-to-one. The edge of the orthographic projection of the second opening 430 on the first surface is located outside the corresponding bonding region 410. That is, the bonding region 410 is completely exposed from the corresponding first openings 420 and second openings 430. The LED chip can be placed in the space formed by the connection of the first openings 420 and the second openings 430.

[0071] Preferably, the orthographic projection of the first opening 420 on the first surface covers the orthographic projection of the corresponding second opening 430 on the first surface, that is, the orthographic projection of the second opening 430 on the first surface coincides with the orthographic projection of the corresponding first opening 420 on the first surface, or the orthographic projection of the second opening 430 on the first surface falls within the orthographic projection of the corresponding first opening 420 on the first surface. Figure 8 Draw the scenario where both scenarios exist. All second openings 430 have the same size, slightly larger than the LED chip size. For example, the boundary of the second opening 430 extends 2-3 micrometers beyond the edge of the LED chip, allowing the LED chip to be placed smoothly within the second opening 430 without easily flipping over.

[0072] Please combine Figure 8 See Figure 9 , Figure 9 for Figure 8A schematic diagram of the deformable layer undergoing deformation. When bonding the LED chip 500 to the backplane body 41, the transfer head 600 first places the LED chip 500 into the first opening 420 and the second opening 430. Then, the deformable layer 42 deforms, reducing the size of the first opening 420. At least a portion of the reduced-size first opening 420 has its orthographic projection on the first surface located within the bonding region 410. This embodiment uses the case where a portion of the first opening 420 has its orthographic projection on the first surface located within the bonding region 410 as an example to illustrate the bonding process between the driving backplane and the LED chip 500 in this application.

[0073] The depth of the second opening 430 is preferably greater than or equal to the thickness of the LED chip 500, so that the surface of the deformable layer 42 away from the back plate body 41 naturally exceeds the surface of the LED chip away from the back plate body 41, and the sacrificial layer 43 provides support for the deformable layer 42. Figure 8 and Figure 9 The diagram illustrates the case where the depth of the second opening 430 is equal to the thickness of the LED chip 500.

[0074] Specifically, all first openings 420 are divided into first sub-holes 420a and second sub-holes 420b, with the size of the first sub-hole 420a being smaller than the size of the second sub-hole 420b. After the deformable layer 42 deforms, the deformable layer 42 surrounding the first sub-hole 420a extends towards the center of the first sub-hole 420a and to the back surface of the LED chip 500, thus reducing the size of the first sub-hole 420a and ensuring that its orthographic projection on the first surface lies within the bonding region 410. Around the second sub-hole 420b, the extended deformable layer 42 still does not contact the LED chip 500, ensuring that the orthographic projection of the second sub-hole 420b on the first surface covers the corresponding bonding region 410.

[0075] During the subsequent separation of the LED chip 500 from the transfer head 600, the deformable layer 42 extending from the first sub-hole 420a to the back of the LED chip 500 can apply force to the LED chip 500 from the back, making it easier for the LED chip 500 to separate from the transfer head 600 and to bond to the bonding region 410. The deformable layer 42 around the second sub-hole 420b cannot apply force to the LED chip 500. If the adhesion force between the LED chip 500 and the transfer head 600 is pre-set to be greater than the adhesion force between the LED chip 500 and the bonding region 410, the LED chip 500 corresponding to the second sub-hole 420b will not separate from the transfer head 600. This allows the driving backplane provided in this embodiment to achieve selective bonding of LED chips. By setting the distribution of the first sub-hole 420a and the second sub-hole 420b in the first opening 420, the LED chip can be bonded to a pre-set portion of the bonding region 410 on the driving backplane, expanding the functionality and application scenarios of the driving backplane in this application.

[0076] Furthermore, the second opening 430 also serves to limit the LED chip 500, making it easier to align the LED chip 500 with the bonding area 410 and reducing the probability of rotational misalignment of the LED chip 500 during the bonding process. Therefore, the driving backplate provided in this embodiment can also improve the transfer yield of the mass transfer process.

[0077] Preferably, in the driving backplane described in the above embodiments, the deformable layer can be removed, or the deformable layer can be removed together with the sacrificial layer, reducing the obstruction of light emitted from the side of the LED chip after bonding, thereby improving the light emission efficiency of the LED chip.

[0078] Based on the same inventive concept, this application also provides a bonding method, please refer to [link to relevant documentation]. Figure 10 , Figure 10 This is a flowchart illustrating one embodiment of the bonding method of this application, which includes the following steps.

[0079] Step S11: Provide the drive backplane.

[0080] Wherein, the drive backplane is the drive backplane described in any of the above embodiments, and this embodiment uses... Figure 5 The following explanation uses the drive backplane shown as an example.

[0081] Step S12: The transfer head is positioned opposite to the bonding area, and the LED chip attached to the transfer head is brought into contact with the bonding area; wherein the edge of the orthographic projection of the LED chip on the plane of the transfer head is located on the periphery of the corresponding area of ​​the transfer head.

[0082] Please see Figure 11 , Figure 11 for Figure 10The schematic diagram of the structure corresponding to one embodiment of step S12 shows that the transfer head 600 is positioned opposite to the bonding region 310, and the LED chip 500 attached to the transfer head 600 is in contact with the bonding region 310. Multiple transfer heads 600 are disposed on one side of the transfer substrate, allowing multiple transfer heads 600 to be simultaneously positioned opposite to multiple bonding regions 310. The edge of the orthographic projection of the LED chip 500 onto the plane of the transfer head 600 is located at the periphery of the corresponding region of the transfer head 600. That is, the surface of the transfer head 600 still has a partially empty area corresponding to the periphery of the LED chip 500, providing space for the deformable layer 32 to deform.

[0083] Step S13, squeeze the transfer head and / or the backplate body to deform the deformable layer; wherein, after the deformable layer is deformed, at least a portion of the deformable layer around the first opening extends to the surface of the corresponding LED chip away from the bonding area.

[0084] Please continue reading. Figure 6 After the transfer head 600 is positioned opposite the bonding region 310, it is pressed from the side of the transfer head 600 away from the LED chip 500 (as shown by arrow P1) and / or from the side of the backplate body 31 away from the deformable layer 32 (as shown by arrow P2) to deform the deformable layer 32, reducing the size of the first opening 320, and at least a portion of the deformable layer 32 around the reduced first opening 320 extends to the surface of the corresponding LED chip 500 away from the bonding region 310. This embodiment utilizes... Figure 5 The drive backplate is bonded, and the deformable layer 32 around all the first openings 320 after being reduced in size extends to the surface of the corresponding LED chip 500 away from the bonding area 310.

[0085] Step S14: Move the transfer head away from the driver backplate, leaving at least a portion of the LED chips corresponding to the first opening on the driver backplate.

[0086] Please combine Figure 6 See Figure 12 , Figure 12 for Figure 11 In the schematic diagram corresponding to the embodiment of step S14, after the deformable layer 32 is deformed by compression, the transfer head 600 moves away from the driving back plate. During this process, the deformable layer 32 extending to the back of the LED chip 500 applies force to the LED chip 500. In the bonding direction, if the first adhesion force between the LED chip 500 and the transfer head 600 is less than the sum of the force applied by the deformable layer 32 to the LED chip 500 and the second adhesion force between the LED chip 500 and the bonding region 310, the LED chip 500 separates from the transfer head 600 and remains on the corresponding bonding region 310, and adheres to the bonding electrode.

[0087] In this embodiment, it is preferable to set the first bonding force to be less than or equal to the second bonding force. Then, the deformable layer 32 only needs to apply a slight force to the LED chip 500 to separate the LED chip 500 from the transfer head 600 and bond it to the bonding region 310. Figure 12 It can be seen that all 500 LED chips remain on the driver backplane.

[0088] The bonding method provided in this embodiment can improve the transfer yield of the mass transfer process.

[0089] In other implementations, for example, using Figure 8 When bonding the drive backplane shown, please refer to the following documentation. Figure 8 and Figure 9 All first openings 420 are divided into first sub-holes 420a and second sub-holes 420b, with the size of the first sub-hole 420a being smaller than the size of the second sub-hole 420b. Furthermore, the first adhesion force between the LED chip 500 and the transfer head 600 is set to be greater than the second adhesion force between the LED chip 500 and the bonding region 410.

[0090] After the deformable layer 42 is deformed under pressure, during the process of the transfer head 600 moving away from the driving backplate, only the deformable layer 42 around the first sub-hole 420a extends to the surface of the corresponding LED chip 500 away from the bonding area 410. At this time, in the bonding direction, if the sum of the force exerted by the deformable layer 42 around the first sub-hole 420a on the LED chip 500 and the second bonding force is greater than the first bonding force, the LED chip 500 corresponding to the first sub-hole 420a separates from the transfer head 600 and remains on the driving backplate. However, the deformable layer 42 around the second sub-hole 420b cannot exert force on the LED chip 500, and the aforementioned first bonding force is greater than the second bonding force. Therefore, during the process of the transfer head 600 moving away from the driving backplate, the LED chip 500 corresponding to the second sub-hole 420b does not separate from the transfer head 600 but follows the transfer head 600 away from the driving backplate. See details... Figure 13 , Figure 13 for Figure 11 A schematic diagram of the structure corresponding to another embodiment of step S14.

[0091] The bonding method provided in this embodiment can improve the transfer yield of the mass transfer process and can also achieve selective bonding of LED chips.

[0092] The bonding methods using the drive backplane described in other embodiments can be referred to the description of the above embodiments, and will not be illustrated here.

[0093] In one embodiment, based on the embodiment corresponding to the above bonding method, after the step of moving the transfer head away from the drive backplane, the following step is further included:

[0094] Remove the deformable layer, or, if the drive backplane contains a sacrificial layer, remove both the sacrificial layer and the deformable layer.

[0095] Please combine Figure 12 See Figure 14 , Figure 14 This is a schematic diagram of a bonding embodiment. Figure 12 Based on the structure shown, after removing the sacrificial layer 33 and the deformable layer 32, for example, by irradiating the interface between the sacrificial layer 33 and the backplate body 31 with a laser, the two are separated, resulting in... Figure 14 The bonding structure shown reduces the shading of the sacrificial layer 33 and the deformable layer 32 on the light emitted by the LED chip 500, thereby improving the light extraction efficiency of the LED chip.

[0096] The above description is merely an embodiment of this application and does not limit the patent scope of this application. Any equivalent structural or procedural transformations made using the content of this application's specification and drawings, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of this application.

Claims

1. A drive backplane, characterized in that, include: A backplate body, wherein the first surface of the backplate body has a plurality of bonding areas, the bonding areas being used for bonding with an LED chip; A deformable layer is disposed on the first surface. The deformable layer has a plurality of through first openings, one first opening corresponding to one bonding region. The edge of the orthographic projection of the first opening on the first surface is located outside the corresponding bonding region. The distance from the surface of the deformable layer away from the backplate body to the first surface is greater than the thickness of the LED chip. When the LED chip is bonded to the backplane body, the deformable layer deforms so that at least a portion of the first opening's orthogonal projection on the first surface lies within the bonding area.

2. The drive backplane according to claim 1, characterized in that, When the LED chip is bonded to the backplane body, after the deformable layer deforms, the orthographic projection of all the first openings on the first surface is located within the corresponding bonding area.

3. The drive backplane according to claim 1, characterized in that, All the first openings are divided into a first sub-hole and a second sub-hole, and the size of the first sub-hole is smaller than the size of the second sub-hole; When the LED chip is bonded to the backplane body, after the deformable layer is deformed, the orthographic projection of the first sub-hole on the first surface is located within the corresponding bonding area, and the orthographic projection of the second sub-hole on the first surface covers the corresponding bonding area.

4. The drive backplane according to any one of claims 1-3, characterized in that, Also includes: A sacrificial layer is stacked between the backplate body and the deformable layer; the sacrificial layer is provided with a plurality of through second openings, the second openings, the first openings, and the bonding regions are corresponding one-to-one, and the edge of the orthographic projection of the second opening on the first surface is located outside the corresponding bonding region.

5. The drive backplane according to claim 4, characterized in that, The deformable layer can be removed along with the sacrificial layer.

6. The drive backplane according to claim 4, characterized in that, The orthographic projection of the first opening onto the first surface covers the orthographic projection of the corresponding second opening onto the first surface.

7. The drive backplane according to claim 4, characterized in that, The depth of the second opening is greater than or equal to the thickness of the LED chip.

8. The drive backplane according to claim 4, characterized in that, The inner wall shape of the second opening matches the outer surface shape of the LED chip.

9. A bonding method, characterized in that, include: Provide a drive backplane as described in any one of claims 1-8; The transfer head is positioned opposite the bonding region, and the LED chip attached to the transfer head is brought into contact with the bonding region; wherein the edge of the orthographic projection of the LED chip onto the plane of the transfer head is located on the periphery of the corresponding region of the transfer head. The transfer head and / or the backplate body are squeezed to deform the deformable layer; wherein, after the deformable layer is deformed, at least a portion of the deformable layer around the first opening extends to the surface of the corresponding LED chip away from the bonding region; Move the transfer head away from the drive backplate, and leave the LED chip corresponding to at least a portion of the first opening on the drive backplate.

10. The bonding method according to claim 9, characterized in that, The first adhesion force between the LED chip and the transfer head is less than or equal to the second adhesion force between the LED chip and the bonding region; The step of squeezing the transfer head and / or the drive backplate to deform the deformable layer includes: The transfer head and / or the drive backplate are squeezed; wherein, after the deformable layer is deformed, all of the deformable layer around the first opening extends to the surface of the corresponding LED chip away from the bonding region.

11. The bonding method according to claim 9, characterized in that, All the first openings are divided into first sub-holes and second sub-holes. The size of the first sub-hole is smaller than the size of the second sub-hole, and the first adhesion force between the LED chip and the transfer head is greater than the second adhesion force between the LED chip and the bonding area. The step of squeezing the transfer head and / or the drive backplate to deform the deformable layer includes: The transfer head and / or the drive backplate are squeezed; wherein, after the deformable layer is deformed, only the deformable layer around the first sub-hole extends to the surface of the corresponding LED chip away from the bonding area, and in the bonding direction, the sum of the force exerted by the deformable layer around the first sub-hole on the LED chip and the second bonding force is greater than the first bonding force.

12. The bonding method according to any one of claims 9-11, characterized in that, After the step of moving the transfer head away from the drive backplate, the method further includes: Remove the deformable layer.

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