Mass transfer method, display panel and display device

Abstract

The present application relates to the technical field of mass transfer, and particularly relates to a mass transfer method, a display panel and a display device, the method comprising the following steps: providing a growth substrate provided with a plurality of independent light emitting chips; coating a light-proof adhesive material on the side of the growth substrate provided with the light emitting chips; the height of the light-proof adhesive material is greater than the height of the light emitting chips; then performing selective laser peeling on the light emitting chips to be transferred on the growth substrate; the peeled chips are embedded in the light-proof adhesive material to a certain depth under the action of gas force; the growth substrate is removed; the light-proof adhesive material carries the light emitting chips to be transferred; the light-proof adhesive material corresponding to the electrodes of the light emitting chips is etched to expose the electrodes; and the side is bonded to the metal pads on the driving back plate through alignment; the light-proof adhesive material is used as a transfer substrate to save the transfer times, and the packaging purpose is achieved synchronously, the packaging steps are saved, and the product yield is improved.

Description

Technical Field

[0001] This invention relates to the field of mass transfer technology, and more specifically, to a mass transfer method, a display panel, and a display device. Background Technology

[0002] Currently, the industry's mass transfer process involves first transferring the chip from the COW (Chip on Wafer) to a temporary COC (Chip on Carrier) substrate, then from the COC to the PDMS substrate, and finally transferring it onto the LTPS-TFT backplane. This entire process requires three mass transfers of the chip, significantly increasing the risk of poor yield on the subsequent backplane transfer and resulting in high transfer costs. After the transfer, a black adhesive encapsulation process is also required to prevent optical crosstalk, making the process quite complex. Summary of the Invention

[0003] The purpose of this invention is to provide a mass transfer method, a display panel, and a display device to reduce the number of transfers and save packaging steps, thereby improving product yield.

[0004] To achieve the above objectives, the technical solutions adopted in the embodiments of the present invention are as follows:

[0005] In a first aspect, a mass transfer method is provided, the method comprising: providing a growth substrate on which multiple independent light-emitting chips are disposed; coating an opaque adhesive layer on one side of the growth substrate on which the light-emitting chips are disposed, wherein the height of the opaque adhesive layer after curing is greater than the height of the light-emitting chips; selectively laser-peeling the light-emitting chips to be transferred on the growth substrate, wherein the light-emitting chips to be transferred are embedded in the opaque adhesive layer at a certain distance away from the growth substrate under the action of gas generated by laser peeling; removing the growth substrate, wherein the opaque adhesive layer carries away the light-emitting chips to be transferred; etching the opaque adhesive layer at the electrode corresponding to the light-emitting chips to expose the electrodes of the light-emitting chips; and aligning and bonding the side of the opaque adhesive layer exposed at the electrode of the light-emitting chips to metal pads on a driving backplane.

[0006] In a second aspect, a display panel includes: a driving backplate having metal pads; an opaque adhesive having multiple light-emitting chips embedded within it using the mass transfer method described above, with grooves formed at the electrodes of the light-emitting chips to expose the electrodes, and correspondingly bonded to the metal pads on the driving backplate; the side of the opaque adhesive away from the electrodes of the light-emitting chips being at the same horizontal plane as the light-emitting surface of the light-emitting chips.

[0007] Thirdly, a display device includes a controller and the display panel, wherein the display panel displays different images under the control of the controller.

[0008] This invention provides a mass transfer method, a display panel, and a display device. The display device is equipped with a display panel for displaying images. The display panel is obtained through a mass transfer method, which includes: providing a growth substrate with multiple independent light-emitting chips; coating an opaque adhesive layer on one side of the growth substrate where the light-emitting chips are located, the height of the opaque adhesive layer being greater than the height of the light-emitting chips; selectively laser-peeling the light-emitting chips to be transferred on the growth substrate; the peeled chips are embedded into the opaque adhesive layer to a certain depth under gas pressure; thereby removing the growth substrate; the opaque adhesive layer carries away the light-emitting chips to be transferred; etching the opaque adhesive layer at the electrode locations of the light-emitting chips to expose the electrodes; and aligning and bonding this side with metal pads on a driver backplane. This solution uses the opaque adhesive layer as a transfer substrate, saving the number of transfer steps. Furthermore, the opaque adhesive layer is ultimately directly encapsulated with the driver backplane without being removed, achieving the encapsulation purpose simultaneously and saving the step of separate encapsulation, thus improving product yield.

[0009] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, preferred embodiments are described below in detail with reference to the accompanying drawings. Attached Figure Description

[0010] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0011] Figure 1 A schematic flowchart of a mass transfer method provided by an embodiment of the present invention is shown.

[0012] Figure 2 A schematic diagram of a growth substrate provided in an embodiment of the present invention is shown.

[0013] Figure 3 This diagram illustrates a coating of an opaque adhesive material according to an embodiment of the present invention.

[0014] Figure 4 This diagram illustrates a laser-stripped light-emitting chip according to an embodiment of the present invention.

[0015] Figure 5 This diagram illustrates a method for removing a growth substrate according to an embodiment of the present invention.

[0016] Figure 6 This diagram illustrates an embodiment of etching an opaque adhesive material according to an embodiment of the present invention.

[0017] Figure 7 This diagram illustrates a bonding process between a light-emitting chip and a driving backplane, as provided in an embodiment of the present invention.

[0018] Figure 8 This diagram illustrates another method of etching an opaque adhesive material according to an embodiment of the present invention.

[0019] Figure 9 A schematic diagram of flux formation provided by an embodiment of the present invention is shown.

[0020] Figure 10 This diagram illustrates another method of bonding a light-emitting chip to a driving backplane, as provided in an embodiment of the present invention.

[0021] Figure 11 A schematic diagram of a laser welding method provided by an embodiment of the present invention is shown.

[0022] Figure 12 This diagram illustrates another method of etching an opaque adhesive material according to an embodiment of the present invention.

[0023] Illustration:

[0024] 110 - Growth substrate; 120 - Light-emitting chip; 130 - Opaque adhesive; 140 - Groove; 150 - Drive backplate; 160 - Metal pad; 170 - Flux. Detailed Implementation

[0025] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0026] It should be noted that similar reference numerals and letters in the following figures indicate similar items; therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures. Furthermore, in the description of this invention, terms such as "first," "second," etc., are used only to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0027] Please refer to Figure 1 This is a flowchart illustrating a mass transfer method provided in an embodiment of the present invention. The method includes:

[0028] S110 provides a growth substrate on which multiple independent light-emitting chips are disposed.

[0029] like Figure 2 The diagram shown is a schematic diagram of the structure of a growth substrate 110 provided in an embodiment of the present invention. The growth substrate 110 is provided with a plurality of independent light-emitting chips 120. The growth substrate 110 may be, but is not limited to, a sapphire substrate. The light-emitting chip 120 may be, but is not limited to, a red light-emitting chip with a red light color, a green light-emitting chip with a green light color, or a blue light-emitting chip with a blue light color. Further, the light-emitting chip 120 may be a MicroLED or a MiniLED.

[0030] S120, an opaque adhesive is coated on the entire side of the growth substrate on which the light-emitting chip is disposed, and after curing, the height of the opaque adhesive is greater than the height of the light-emitting chip.

[0031] like Figure 3 The diagram shown is a schematic representation of an opaque adhesive 130 provided in an embodiment of the present invention. The opaque adhesive 130 is coated in a single layer on one side of the growth substrate 110 where the light-emitting chip 120 is disposed. The height of the cured opaque adhesive 130 is greater than the height of the light-emitting chip 120. Figure 3 As shown, the height of the opaque adhesive 130 can, by way of example, be approximately H higher than the height of the light-emitting chip 120, in μm. The opaque adhesive 130 can be silicone or epoxy resin, doped with a predetermined concentration of a blocking material. This blocking material can be, for example, any or a combination of silicon dioxide (SiO2), titanium dioxide (TiO2), boron nitride (BN), and zirconium dioxide (ZrO2). It should be noted that if the blocking material accounts for more than 5% of the weight of the opaque adhesive 130, an opaque effect will be achieved. Furthermore, the opaque adhesive 130 can also be a black memory-effect hydrogel or a black nano-self-healing adhesive to achieve the opaque effect.

[0032] S130, selectively laser-peel the light-emitting chip to be transferred on the growth substrate, and embed the light-emitting chip to be transferred into the opaque adhesive material at a certain distance away from the growth substrate under the action of the gas generated by the laser peeling.

[0033] like Figure 4The diagram shown is a schematic of a laser stripping process provided in an embodiment of the present invention. Selective laser stripping is performed on the light-emitting chip to be transferred on the growth substrate 110. Since the light-emitting chip includes at least an N-type gallium nitride layer, a light-emitting layer, and a P-type gallium nitride layer, under the action of the laser, the N-type gallium nitride layer decomposes into Ga and N2. Under the action of the gas, the light-emitting chip 120 that has been selectively laser stripped will be moved away from the growth substrate 110 at a certain distance and embedded in the opaque adhesive 130, while the light-emitting chip 120 that has not been laser stripped will remain tightly connected to the growth substrate 110.

[0034] S140, the growth substrate is removed, and the opaque adhesive material carries away the light-emitting chip to be transferred.

[0035] like Figure 5 The diagram shown is a schematic of removing the growth substrate 110 according to an embodiment of the present invention. That is, the opaque adhesive 130 is peeled off from the growth substrate 110. Since selective laser peeling was performed on some of the light-emitting chips 120 in S130, these light-emitting chips 120 are not connected to the growth substrate 110 and are embedded in the opaque adhesive 130 to a certain depth. However, some light-emitting chips 120 are not selectively peeled off, and they still remain in close contact with the growth substrate 110. Therefore, when the opaque adhesive 130 is peeled off from the growth substrate 110, the light-emitting chips 120 that have been selectively peeled off will be taken away. The holding force of the light-emitting chips 120 that have not been selectively peeled off from the growth substrate 110 is greater than the adhesion force of the opaque adhesive 130 to them, and they will continue to remain on the growth substrate 110. Furthermore, based on the actual spacing requirements on the drive backplane 150, the light-emitting chips 120 with a predetermined spacing can be selectively transferred away in this step using the opaque adhesive 130. At this time, the opaque adhesive 130 serves as a "temporary substrate," eliminating the need for additional temporary substrates to support it. This saves on the use of temporary substrates and reduces the number of transfers, which is more conducive to improving the yield of the final product.

[0036] S150, etch the opaque adhesive material at the corresponding position of the electrodes of the light-emitting chip to expose the electrodes of the light-emitting chip.

[0037] like Figure 6The diagram illustrates an embodiment of the present invention involving the etching of an opaque adhesive 130. The etching of the opaque adhesive 130 at the electrode location of the light-emitting chip 120 forms a groove 140, exposing the electrode of the light-emitting chip 120. Specifically, a pattern can be first created on the surface of the opaque adhesive 130 near the electrode of the light-emitting chip 120, and then the groove 140 is further etched according to the pattern. It should be noted that the depth of the groove 140 can be equal to the depth of the metal pad 160 on the driving backplate 150, so that when the electrode of the light-emitting chip 120 is bonded to the metal pad 160, the surface of the opaque adhesive 130 near the electrode of the light-emitting chip 120 precisely adheres to the surface of the driving backplate 150. The opaque adhesive 130 can then be directly used as an encapsulation layer without additional encapsulation, saving process steps. Furthermore, due to its opaque nature, it also significantly improves the contrast of the light-emitting chip 120, effectively avoiding color crosstalk problems. The depth of the groove 140 can also be less than the depth of the metal pad 160 on the drive backplate 150. In this case, when the electrode of the light-emitting chip 120 is bonded to the metal pad 160, the surface of the opaque adhesive 130 near the electrode of the light-emitting chip 120 is still a certain distance away from the drive backplate 150. At this time, additional adhesive needs to be filled in the gap to make the encapsulation more secure. However, the depth of the groove 140 must not be greater than the depth of the metal pad 160, otherwise it will cause a cold solder joint problem.

[0038] S160, the opaque adhesive material is exposed on the electrode side of the light-emitting chip and aligned and bonded to the metal pads on the driving backplate.

[0039] like Figure 7 The diagram shown is a schematic of bonding a light-emitting chip 120 to a driving backplate 150 according to an embodiment of the present invention. That is, the side of the opaque adhesive 130 exposed to the electrode of the light-emitting chip 120 is aligned and bonded to the metal pad 160 on the driving backplate 150. Since the side of the opaque adhesive 130 exposed to the electrode of the light-emitting chip 120 has a groove 140, it is easier to align during bonding, which improves the bonding effect and avoids problems such as misalignment.

[0040] like Figure 8 The diagram shown is another schematic diagram of etching the opaque adhesive 130 according to an embodiment of the present invention. Since the opaque adhesive 130 has the property of being opaque, in order to avoid affecting the light emission effect of the light-emitting chip 120, after the light-emitting chip 120 is bonded to the driving backplate 150, the surface of the opaque adhesive 130 away from the driving backplate 150 is also etched to expose the light-emitting surface of the light-emitting chip 120.

[0041] Further, please refer to Figure 9The diagram shown is a schematic of flux filling 170 provided in an embodiment of the present invention. To improve the bonding effect between the light-emitting chip 120 and the metal pad 160 of the driving backplate 150, flux 170 can be filled into the groove 140 after etching to form the groove. The flux 170 serves as a bridge for the electrical connection between the electrode of the light-emitting chip 120 and the metal pad 160. Specifically, the sum of the height of the flux 170 and the height of the metal pad 160 on the driving backplate 150 is equal to the depth of the groove 140. This ensures that after the electrode of the light-emitting chip 120 is bonded to the metal pad 160, the surface of the opaque adhesive 130 near the electrode of the light-emitting chip 120 adheres to the surface of the driving backplate 150. The opaque adhesive 130 directly serves as an encapsulation layer, eliminating the need for additional encapsulation, saving encapsulation steps, and improving product yield. At the same time, the opaque nature of the opaque adhesive 130 also results in higher contrast between multiple light-emitting chips 120, effectively preventing light crosstalk problems. In another scenario, the sum of the height of the flux 170 and the metal pads 160 on the drive backplate 150 is greater than the depth of the groove 140. After the electrodes of the light-emitting chip 120 are bonded to the metal pads 160, there is still a gap between the surface of the opaque adhesive 130 near the electrodes of the light-emitting chip 120 and the drive backplate 150. In this case, adhesive is needed to fill the gap for encapsulation to improve the overall stability of the device.

[0042] Furthermore, please refer to Figure 10 This is a schematic diagram of a light-emitting chip 120 being bonded to a driving backplane 150 according to an embodiment of the present invention. After bonding, as shown... Figure 11 By irradiating the molten flux 170 with a laser, the electrodes of the light-emitting chip 120 are tightly welded to the metal pads 160. Similarly, as... Figure 12 As shown, in order to improve the light emission effect, after bonding is completed, the surface of the opaque adhesive 130 away from the driving backplate 150 is etched to expose the light emission surface of the light-emitting chip 120.

[0043] As another embodiment, the present invention also provides a display panel, the structure of which is as follows: Figure 8 Or such as Figure 12 As shown, it includes:

[0044] A drive backplane 150 is provided with metal pads 160.

[0045] The opaque adhesive 130 is embedded with multiple light-emitting chips 120 using the mass transfer method described above. A groove 140 is formed at the electrode of the light-emitting chip 120 to expose the electrode of the light-emitting chip 120, and is correspondingly bonded to the metal pad 160 on the driving backplate 150. The side of the opaque adhesive 130 away from the electrode of the light-emitting chip 120 is at the same level as the light-emitting surface of the light-emitting chip 120.

[0046] Furthermore, the display panel also includes flux 170, which is disposed in the groove 140 and located between the electrode of the light-emitting chip 120 and the metal pad 160, and plays an auxiliary role in soldering.

[0047] As another implementation, the present invention also provides a display device, which includes a controller and the aforementioned display panel. The display panel displays different images under the control of the controller. The display device may be, but is not limited to, electronic devices with displays such as computers, tablets, and mobile phones.

[0048] In summary, the present invention provides a mass transfer method, a display panel, and a display device. The display device is equipped with a display panel for displaying images. The display panel is obtained through a mass transfer method, which includes: providing a growth substrate with multiple independent light-emitting chips; coating an opaque adhesive layer on one side of the growth substrate where the light-emitting chips are located, the height of the opaque adhesive layer being greater than the height of the light-emitting chips; selectively laser-peeling the light-emitting chips to be transferred on the growth substrate; the peeled chips are embedded into the opaque adhesive layer to a certain depth under the force of gas; thereby removing the growth substrate; the opaque adhesive layer carrying away the light-emitting chips to be transferred; etching the opaque adhesive layer at the electrode locations of the light-emitting chips to expose the electrodes; and aligning and bonding this side with metal pads on a driving backplane. This solution uses the opaque adhesive layer as a transfer substrate, saving the number of transfer steps. Furthermore, the opaque adhesive layer is ultimately directly encapsulated with the driving backplane without being removed, achieving the encapsulation purpose simultaneously and saving the step of separate encapsulation, thus improving product yield.

[0049] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0050] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the invention should be included within the scope of protection of the invention. It should be noted that similar reference numerals and letters in the following figures denote similar items; therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0051] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A mass transfer method, characterized in that, The method includes: A growth substrate is provided, on which multiple independent light-emitting chips are disposed; An opaque adhesive is coated on the entire side of the growth substrate on which the light-emitting chip is disposed. After curing, the height of the opaque adhesive is greater than the height of the light-emitting chip. Selective laser peeling is performed on the light-emitting chip to be transferred on the growth substrate. Under the action of the gas generated by the laser peeling, the light-emitting chip to be transferred is embedded in the opaque adhesive material at a certain distance away from the growth substrate. The growth substrate is removed, and the opaque adhesive material carries away the light-emitting chip to be transferred. The opaque adhesive material corresponding to the electrodes of the light-emitting chip is etched to expose the electrodes of the light-emitting chip; The opaque adhesive material is exposed on the electrode side of the light-emitting chip and aligned and bonded to the metal pads on the driving backplate.

2. The mass transfer method as described in claim 1, characterized in that, The method further includes: After etching the opaque adhesive material corresponding to the electrode of the light-emitting chip, a groove is formed, and flux is filled into each groove, with the flux connected to the electrode.

3. The mass transfer method as described in claim 2, characterized in that, The sum of the height of the flux and the height of the metal pads on the drive backplate is equal to the depth of the groove.

4. The mass transfer method as described in claim 2, characterized in that, If the sum of the height of the flux and the height of the metal pads on the drive backplate is greater than the depth of the groove, then the gap between the opaque adhesive and the drive backplate is filled with adhesive for encapsulation.

5. The mass transfer method as described in claim 1, characterized in that, The method further includes: After the opaque adhesive material protruding from the electrode side of the light-emitting chip is aligned and bonded to the metal pads on the driving backplate, the side of the opaque adhesive material away from the driving backplate is etched to expose the light-emitting surface of the light-emitting chip.

6. The mass transfer method as described in claim 1, characterized in that, The opaque adhesive material includes silicone or epoxy resin, wherein the silicone or epoxy resin is doped with a predetermined concentration of a barrier substance, wherein the barrier substance includes one or more of silicon dioxide, titanium dioxide, boron nitride, or zirconium dioxide.

7. The mass transfer method as described in claim 1, characterized in that, The light-emitting chip includes a red light chip that emits red light, a green light chip that emits green light, or a blue light chip that emits blue light.

8. A display panel, characterized in that, include: A drive backplane, wherein metal pads are provided on the drive backplane; An opaque adhesive is used to embed multiple light-emitting chips using the mass transfer method described in any one of claims 1-7. A groove is formed at the electrode of the light-emitting chip to expose the electrode of the light-emitting chip, and it is bonded to the metal pad on the driving backplate. The side of the opaque adhesive away from the electrode of the light-emitting chip is at the same level as the light-emitting surface of the light-emitting chip.

9. The display panel as described in claim 8, characterized in that, The display panel also includes a flux disposed in the groove and located between the electrode of the light-emitting chip and the metal pad.

10. A display device, characterized in that, The display device includes a controller and a display panel as described in any one of claims 8-9, wherein the display panel displays different images under the control of the controller.

Images