Chip transfer method, Micro-LED display device and manufacturing method thereof

Abstract

The present application provides a chip transfer method, a Micro-LED display device and a manufacturing method thereof. The tape is adhered to the original substrate with chips under the action of pressure, the tape and the chips are peeled off from the original substrate together, and under the action of pressure, the tape with chips is adhered to the provided glass substrate to exclude air. Ultraviolet light is used for irradiation to weaken the adhesiveness of the tape. Finally, the tape with weakened adhesiveness and chips is adhered to the target substrate to transfer the chips to the target substrate. In this solution, the adhesiveness of the tape is weakened by means of ultraviolet light irradiation, and a temporary glass substrate is introduced while reducing the adhesiveness, so that the tape quickly reduces its adhesiveness in an oxygen-excluding environment, shortening the process time, reducing the process cost, and improving the transfer yield and accuracy.

Description

Technical Field

[0001] The present invention relates to the field of semiconductor manufacturing technology, and in particular, to a chip transfer method, a Micro-LED display device, and a manufacturing method thereof. Background Art

[0002] In the field of Micro-LED display, a large number of micro-LED chips fabricated on a wafer need to be transferred onto a circuit substrate using transfer technology and further packaged together with other chips. Mass transfer is a key core technology, and the yield, precision, speed, and transfer of programmable micro-LED chips are the core to reduce production costs.

[0003] In the prior art, there are mainly PDMS stamps, fluid self-assembly, electrostatic assembly, magnetic adsorption, roller transfer technology, etc. Currently, the process of weakening the adhesion of the transfer tape mainly involves heating and cooling the hot tape, etc. This process takes a long time and results in increased costs. Moreover, the hot tape reduces adhesion based on the principle of thermal foaming. During the adhesion reduction process, the volume of the foaming glue expands, which easily causes chip displacement, and the temperature also easily causes thermal deformation of the substrate, bringing many problems with transfer precision.

[0004] In addition, there is also a method of irradiating a transfer substrate with light of a preset wavelength to change the adhesion of the transfer substrate and achieve the picking and placing of chips, such as UV tape. Commercial UV tapes have been widely used in wafer dicing in the semiconductor field, but there are few reports on the efficient batch transfer and programmable transfer of micro-semiconductor devices with a scale of several micrometers (3μm - 100μm). Especially for devices with a scale of several micrometers, there are problems such as chip displacement, low yield, difficulty in selective transfer, and low selective precision. Summary of the Invention

[0005] The objectives of the present invention include, for example, providing a chip transfer method, a Micro-LED display device, and a manufacturing method thereof, which can achieve the transfer of chips quickly, with high precision, and high yield.

[0006] Embodiments of the present invention may be implemented as follows:

[0007] In a first aspect, the present invention provides a chip transfer method, the method comprising:

[0008] providing a raw substrate having a plurality of chips to be transferred arranged in an array thereon;

[0009] pressing a tape onto the raw substrate and the chips under pressure;

[0010] peeling the tape and the chips from the raw substrate;

[0011] Under pressure, attach the tape with the chip to the provided glass substrate to expel air. Use ultraviolet light irradiation to weaken the adhesiveness of the tape, and then attach the tape with the weakened adhesiveness and the chip to the target substrate to transfer the chip onto the target substrate.

[0012] In an alternative embodiment, the steps of attaching the tape with the chip to the provided glass substrate to expel air, using ultraviolet light irradiation to weaken the adhesiveness of the tape, and then attaching the tape with the weakened adhesiveness and the chip to the target substrate to transfer the chip onto the target substrate include:

[0013] Attach the tape with the chip to the provided glass substrate to expel air. Use an optical mask and ultraviolet light to irradiate the chip, obtaining the chip in the exposed area and the chip in the non-exposed area, wherein the height of the chip in the exposed area is lower than that of the chip in the non-exposed area.

[0014] Use the tape to sequentially transfer the chips in the non-exposed area onto the first target substrate and transfer the chips in the exposed area onto the second target substrate.

[0015] In an alternative embodiment, the steps of using the tape to sequentially transfer the chips in the non-exposed area onto the first target substrate and transfer the chips in the exposed area onto the second target substrate include:

[0016] Under pressure, attach the tape with all the chips to the first target substrate to transfer the chips in the non-exposed area onto the first target substrate.

[0017] Peel off the tape with the chips in the exposed area from the first target substrate and attach it to the glass substrate. Use ultraviolet light irradiation until the tape is completely de-adhered.

[0018] Attach the completely de-adhered tape with the chips in the exposed area to the second target substrate to transfer the chips in the exposed area onto the second target substrate.

[0019] In an alternative embodiment, the side of the target substrate in contact with the chip has an adhesion layer.

[0020] In an alternative embodiment, the steps of attaching the tape to the original substrate and the chip under pressure include:

[0021] Apply pressure to the tape and the original substrate in the vertical direction.

[0022] Use a vacuum pumping device to evacuate the air between the tape and the original substrate to attach the tape to the original substrate.

[0023] In an alternative embodiment, the step of attaching the tape to the original substrate and the chip under pressure includes:

[0024] Using a roller device to apply uniform pressure to the tape in sequence, so that the tape and the original substrate are attached without bubbles.

[0025] In an alternative embodiment, before the step of attaching the tape to the original substrate and the chip under pressure, the method further includes:

[0026] Immersing the original substrate with the chip in an etching solution to form a weak bonding force between the chip and the original substrate.

[0027] In an alternative embodiment, the irradiation wavelength of the ultraviolet light is 320 nm to 400 nm.

[0028] In a second aspect, the present invention provides a method for manufacturing a Micro-LED display device, including chip transfer and chip array manufacturing, wherein the chip transfer is performed by using the chip transfer method according to any one of the foregoing embodiments.

[0029] In a third aspect, the present invention provides a Micro-LED display device, which is manufactured by using the method for manufacturing a Micro-LED display device according to the foregoing embodiment.

[0030] The beneficial effects of the embodiments of the present invention include, for example:

[0031] The present application provides a chip transfer method, a Micro-LED display device and a manufacturing method. In this chip transfer method, the tape is attached to the original substrate with the chip under pressure, the tape and the chip are peeled off from the original substrate together, and under pressure, the tape with the chip is attached to the provided glass substrate to exclude air. The viscosity of the tape is weakened by ultraviolet light irradiation, and finally the tape with the weakened viscosity and the chip is attached to the target substrate to transfer the chip to the target substrate. In this solution, the viscosity of the tape is weakened by ultraviolet light irradiation, and a temporary glass substrate is introduced while reducing the viscosity, so that the tape quickly reduces viscosity in an oxygen-excluding environment, shortening the process time, reducing the process cost, and improving the transfer yield and accuracy. Description of the Drawings

[0032] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention, and therefore should not be regarded as limiting the scope. For those of ordinary skill in the art, other related drawings can be obtained based on these drawings without creative efforts.

[0033] Figure 1 Flow chart of the chip transfer method provided by the embodiment of the present application;

[0034] Figures 2(a) to 2(h) Schematic diagrams of the steps in the full-surface transfer method provided by the embodiment of the present application;

[0035] Figures 3(a) to 3(f) Schematic diagrams of the steps in which the Au thin-film chip forms a weak bonding force with the original substrate in the embodiment of the present application;

[0036] Figures 4(a) to 4(g) Schematic diagrams of the steps in which the uled chip forms a weak bonding force with the original substrate in the embodiment of the present application;

[0037] Figures 5(a) to 5(j) Schematic diagrams of the steps in the selective transfer method provided by the embodiment of the present application;

[0038] Figure 6 Schematic diagram of the optical mask adopted in the embodiment of the present application and the shape of the chip array after the transfer is performed;

[0039] Figure 7 Schematic diagram of the height curves of the chips in the exposed area and the unexposed area provided by the embodiment of the present application;

[0040] Figure 8 Schematic diagram of the shape of the optical mask adopted in the embodiment of the present application;

[0041] Figure 9 Another schematic diagram of the shape of the optical mask adopted in the embodiment of the present application.

[0042] Icon: 10 - original substrate; 20 - chip; 30 - tape; 40 - glass substrate; 50 - target substrate; 51 - first target substrate; 52 - second target substrate. Detailed implementation manners

[0043] To make the objectives, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Apparently, the described embodiments are some but not all of the embodiments of the present invention. The components of the embodiments of the present invention described and illustrated herein usually can be arranged and designed in various different configurations.

[0044] Therefore, the following detailed description of the embodiments of the present invention provided in the drawings is not intended to limit the scope of the claimed present invention, but merely represents selected embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts fall within the scope of protection of the present invention.

[0045] It should be noted that like reference numerals and letters refer to like items in the following figures, and thus, once an item is defined in one figure, it need not be further defined and explained in subsequent figures.

[0046] In the description of the present invention, it should be noted that if terms such as "upper", "lower", "inner", "outer", etc. are used to indicate the orientation or positional relationship, it is based on the orientation or positional relationship shown in the figures, or the orientation or positional relationship in which the product of the present invention is usually placed during use. This is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus should not be construed as a limitation to the present invention.

[0047] In addition, if terms such as "first", "second", etc. are used only for distinguishing descriptions, they should not be construed as indicating or implying relative importance.

[0048] It should be noted that, without conflict, the features in the embodiments of the present invention can be combined with each other.

[0049] The embodiments of the present application provide a method for transferring a microchip, which can be used to solve the problems existing in the existing transfer methods, such as long process time, difficulty in balancing cost and yield, high difficulty in selective transfer, and low precision of selective transfer. Please refer to Figure 1 and, in combination with Figures 2(a) to 2(h) The following will introduce in detail the specific steps of the chip transfer method provided by the embodiments of the present application.

[0050] S101, please refer to FIG. 2(a), provide an original substrate 10, and a plurality of chips 20 to be transferred are arranged in an array on the original substrate 10.

[0051] In this embodiment, the chips 20 to be transferred can be interconnection electrodes made of Au thin film, or other functional elements based on this material system. That is to say, the transfer method provided in this embodiment can be used for transferring interconnection lines. When the chips 20 on the original substrate 10 are an Au thin film array, the Au thin film can have different shapes, different sizes, and different spacings between each other.

[0052] In addition, the chips 20 to be transferred can also be chips 20 such as uLEDs, LEDs, etc. formed based on material systems such as GaN, GaAs, etc. That is to say, the transfer method provided in this embodiment can transfer a uLED array fabricated through semiconductor processes.

[0053] In this embodiment, the original substrate 10 can be a substrate such as Si, SiO2, etc.

[0054] To facilitate the subsequent transfer of the chip 20 on the original substrate 10, in this embodiment, before peeling the chip 20 from the original substrate 10, the transfer method provided in this embodiment further includes the following steps:

[0055] Immerse the original substrate 10 with the chip 20 in an etching solution to form a weak bonding force between the chip 20 and the original substrate 10.

[0056] In this embodiment, for different application scenarios, there are differences in the etching solution and the process method used.

[0057] For example, when forming a weakening structure for the Au thin film, in this embodiment, the etching solution used can be buffered oxide etchant (BOE), which can be diluted. After etching the original substrate 10 and the chip 20 with the diluted BOE, a weak bonding force can be formed between the chip 20 and the original substrate 10, facilitating the subsequent smooth peeling of the chip 20 from the original substrate 10.

[0058] In this embodiment, the chip 20, such as an Au thin film array, can be fabricated on the original substrate 10 through a photolithography process. After fabrication, the original substrate 10 and the chip 20 are placed into the diluted BOE solution together. Please refer to Figures 3(a) to 3(f) , first, please refer to Fig. 3(a). In this embodiment, taking the original substrate 10 as Si + SiO2 as an example, first, SiO2 can be deposited on the Si substrate.

[0059] Please refer to Fig. 3(b). A photoresist, such as AZ2035, can be coated on the SiO2. As shown in Fig. 3(c) again, the photoresist is partially exposed and developed, thereby exposing part of the SiO2. As shown in Fig. 3(d), an Au thin film is deposited on the exposed SiO2 and the photoresist. For example, the thickness of the Au thin film can be 40 nm to 250 nm. Please refer to Fig. 3(e). The photoresist layer can be removed using a developer. Accordingly, the Au thin film on the photoresist layer is also removed. Finally, as shown in Fig. 3(f), the original substrate 10 and the remaining Au thin film are immersed in the diluted BOE solution. The BOE solution partially etches the SiO2 under the Au thin film, thereby forming a weak bonding force between the Au thin film and the Si substrate, facilitating the subsequent smooth peeling of the Au thin film from the substrate.

[0060] In addition, when it comes to the uled array of the Si-based GaN material system, the etching solution used can be TMAH or KOH.

[0061] Please refer to Figures 4(a) to 4(g), when it comes to the uLED array of the Si-based GaN material system, first, as shown in Figure 4(a), an epitaxial layer can be formed on the Si substrate. Among them, the epitaxial layer includes a buffer layer, an N-GaN layer, a multi-quantum well layer, and a P-GaN layer. Among them, the thickness of the Si substrate can be 800 um, the thickness of the buffer layer can be 1.5 um, the thickness of the N-GaN layer can be 1.6 um, and the thickness of the P-GaN layer can be 150 nm. Of course, only examples are given here for the thickness of each layer, and it is not limited thereto. On this basis, as shown in Figures 4(b) and 4(c), the epitaxial layer can be etched respectively to obtain a first groove and a second groove. Among them, the first groove extends to the N-GaN layer, and the second groove extends to the Si substrate (500 nm - 1 um).

[0062] As shown in Figure 4(d), a SiO2 passivation layer is deposited on the surface of the P-GaN layer and in the first groove. Then, the SiO2 passivation layer is partially etched to form a metal electrode contact hole, as shown in Figure 4(e). As shown in Figure 4(f), metal is deposited in the contact hole. Finally, as shown in Figure 4(g), anisotropic etching of Si is carried out using an etching solution such as TMAH or KOH to form a weak bonding force.

[0063] S102, please refer to Figure 2(b). Under pressure, the tape 30 is bonded to the original substrate 10 and the chip 20.

[0064] In this embodiment, the tape 30 can be a uv tape 30. The tape 30 is bonded to the original substrate 10 and the chip 20 so that the tape 30 can adhere to the chip 20 to be transferred.

[0065] In this embodiment, in order to enable the tape 30 to be perfectly bonded to the chip 20 to be transferred, in a possible implementation manner, it can be achieved through the following method:

[0066] Apply pressure to the tape 30 and the original substrate 10 in the vertical direction, and use a vacuum pumping device to evacuate the air between the tape 30 and the original substrate 10 to bond the tape 30 to the original substrate 10.

[0067] In this embodiment, the perfect bonding of the tape 30 and the original substrate 10 can be achieved by combining the vertical application of pressure and the vacuum pumping method.

[0068] In addition, in another possible implementation manner, the bonding of the tape 30 and the original substrate 10 can also be achieved through the following method:

[0069] Use a roller device to apply uniform pressure to the tape 30 in sequence so that the tape 30 and the original substrate 10 are bonded in a bubble-free state.

[0070] S103, refer to FIG. 2(c), and peel the tape 30 and the chip 20 from the original substrate 10.

[0071] When the tape 30 is well adhered to the original substrate 10, the tape 30 can adhere to the chip 20 well. At this time, the tape 30 on the original substrate 10 can be peeled off. At the same time, the chip 20 attached to the tape 30 will be peeled off from the original substrate 10 together.

[0072] S104, please refer to Figures 2(d) to 2(h) , under pressure, attach the tape 30 with the chip 20 to the provided glass substrate 40 to expel air, irradiate with ultraviolet light to weaken the adhesiveness of the tape 30, and attach the tape 30 with weakened adhesiveness and the chip 20 to the target substrate 50 to transfer the chip 20 to the target substrate 50.

[0073] In this embodiment, a glass substrate 40 is provided as a temporary substrate. After peeling the chip 20 from the original substrate 10 using the tape 30, attach the tape 30 with the chip 20 to the glass substrate 40, as shown in FIG. 2(d). Force can be applied to the tape 30 on the glass substrate 40 to make the tape 30 adhere well to the glass substrate 40. On this basis, ultraviolet light can be used to irradiate the tape 30. The wavelength of the ultraviolet light used can be 320nm to 400nm, and the output power can be 20mw / cm 2 . Under the irradiation of ultraviolet light, the adhesiveness of the tape 30 can be reduced.

[0074] The glass substrate 40 as a temporary substrate can exclude the oxygen environment, enabling the tape 30 to quickly reduce adhesiveness in an oxygen-excluding environment, shortening the process time and reducing the process cost.

[0075] Please refer to FIG. 2(e), peel the tape 30 with reduced adhesiveness from the glass substrate 40, thereby peeling the chip 20 from the glass substrate 40 together. As shown in FIG. 2(f), then attach the peeled tape 30 to the target substrate 50. Among them, the target substrate 50 can be a hard, transparent or flexible substrate such as glass, Si, mica, PET, PO, etc.

[0076] One side of the target substrate 50 that is adhered to the chip 20 has an adhesive layer. The adhesive layer can be an adhesive layer on a UV PET tape, Su8 2002 / 2005, PDMS, TPU, etc. Under the action of the adhesive layer, as shown in FIG. 2(g), when the tape 30 is peeled off from the target substrate 50, the chip 20 will adhere to the target substrate 50. Thus, finally, the chip 20 is transferred to the target substrate 50, as shown in FIG. 2(h).

[0077] In this embodiment, the above method can realize the transfer of the entire surface of the chip 20 array, and all the chips 20 on the original substrate 10 are transferred to the target substrate 50. Among them, by providing a glass substrate 40 as a temporary substrate, an oxygen-excluded environment can be provided, and combined with ultraviolet light irradiation, the adhesive tape 30 can be quickly de-adhesive, thereby shortening the time required for transfer, reducing costs, and also improving the transfer yield and accuracy.

[0078] In this embodiment, two specific implementation cases are listed below to further introduce the above-mentioned whole-surface transfer method.

[0079] Implementation case 1: Achieving 4-inch wafer-level transfer.

[0080] First, the Au thin film array is made on a 4-inch Si+SiO2 substrate by combining the photolithography process and then etched in a diluted BOE solution to form a weak binding force. The thickness, length and width of the Au thin film are 250nm*110um*120um respectively, and the point spacing between the centers of the two Au chips can be 110um.

[0081] Apply pressure evenly to fit the UV tape 30 to the chip to be transferred and the substrate perfectly. A roller tool and a vacuum device can be used to apply force and extract air so that there are bubbles between the tape 30 and the substrate.

[0082] The tape 30 was peeled off and the Au thin film chip was peeled off from the substrate. Then, the tape 30 with the Au thin film chip was evenly bonded to the clean glass substrate 40 under the conditions of 365 nm and 20 mw / cm 2 The adhesive tape 30 is exposed to ultraviolet light for a time greater than or equal to 3 seconds, thereby reducing the viscosity of the adhesive tape 30.

[0083] The adhesive tape 30 after the viscosity reduction is separated from the glass substrate 40, and then pressure is evenly applied to fit the adhesive tape 30 and the final substrate perfectly. Roller equipment can be used in combination with a vacuum device, etc., so that there are no bubbles between the adhesive tape 30 and the final substrate. The final substrate can be a hard, transparent or flexible substrate such as glass, Si, mica, PET, PO, etc. with an adhesive layer. The adhesive layer can be an adhesive layer on a UV PET tape.

[0084] Finally, the tape 30 after the viscosity reduction is peeled off, and the Au thin film chip array will be completely transferred to the final substrate.

[0085] Implementation case 2: ULED blue light array.

[0086] First, fabricate a uLED blue light array to be transferred with weak binding force. Among them, use a Si<111>-GaN substrate. The size of a single uLED is 50um * 80um, the pitch of the center points of the uLEDs is 150um, and the number of uLEDs in the array can be 50 * 50.

[0087] Fully attach the uv tape 30 to the Si substrate. A roller device combined with a vacuum device can be used to ensure bubble-free attachment between the tape 30 and the substrate.

[0088] Peel off the tape 30 and simultaneously peel off the uLED array from the original substrate.

[0089] Attach the tape 30 with the uLED array to a clean glass substrate 40 and expose it under ultraviolet light of 365nm and 20mw / cm 2 for 3s or more, so that the tape 30 quickly reduces its adhesion.

[0090] Attach the tape 30 with reduced adhesion to the final substrate. A roller device combined with a vacuum device can be used to ensure bubble-free attachment between the tape 30 and the final substrate. The final substrate can be a transparent glass with an adhesion layer, and the adhesion layer can be su8-2002 with a thickness of 2um.

[0091] Peel off the tape 30 from the final substrate, and the uLED array will be transferred to the final substrate. In this embodiment, the electrical characteristics of the uLED array before and after transfer do not decay, and the surface of the uLED array is clean without impurity residue.

[0092] The above describes the overall transfer of the chip 20. In this embodiment, selective transfer of the chip 20 can also be achieved. The method of selective transfer will be introduced in detail below.

[0093] In the prior art, if high-precision selective chip transfer is to be achieved, it usually needs to be realized by combining a laser lift-off device with selectively irradiating by laser. This method greatly increases the process cost.

[0094] In this embodiment, when performing selective transfer of the chip 20, it is achieved through the following method. Please refer to Figures 5(a) to 5(j) :

[0095] First, similarly, according to Figures 5(a) to 5(c)As shown, an original substrate 10 is provided, on which there are multiple chips 20, which can be an Au thin film array or chips 20 such as uLEDs and LEDs formed based on material systems such as GaN and GaAs. Then, under pressure, a tape 30 is bonded to the original substrate 10 and the chips 20, and the tape 30 and the chips 20 are peeled off from the original substrate 10. Among them, these three steps are the same as the corresponding steps in the above full-surface transfer, and will not be elaborated in this embodiment.

[0096] Different from the above full-surface transfer, in the selective transfer, the above step S104 is implemented in the following manner:

[0097] Please refer to FIG. 5(d). The tape 30 with the chips 20 is bonded to the provided glass substrate 40, and the chips 20 are irradiated with ultraviolet light using an optical mask, resulting in the chips 20 in the exposed area and the chips 20 in the non-exposed area. Among them, the height of the chips 20 in the exposed area is lower than the height of the chips 20 in the non-exposed area.

[0098] Then, the tape 30 is used to sequentially transfer the chips 20 in the non-exposed area to the first target substrate 51 and the chips 20 in the exposed area to the second target substrate 52.

[0099] In this embodiment, under the action of the optical mask, some of the chips 20 on the original substrate 10 will be exposed and some will not be exposed. The wavelength of the ultraviolet light used can be 365 nm, and the output power can be 20 mw / cm 2 , and the exposure time can be from 0.6 s to 1.5 s. Due to the mechanism of the growth of the photo-responsive polymer, the chips 20 in the exposed area and the chips 20 in the non-exposed area form a height difference.

[0100] In this embodiment, based on the method of ultraviolet light-induced polymerization growth, a height difference is formed in the chip 20 array to be selectively transferred, so that the chips 20 with different heights can be selectively transferred in batches.

[0101] When transferring the chips 20 in the non-exposed area and the chips 20 in the exposed area in batches, first, please refer to FIG. 5(e). The tape 30 that has been partially exposed is peeled off from the original substrate 10, and the chips 20 are peeled off from the original substrate 10 together. Then, the transfer is achieved through the following method:

[0102] Please refer to FIG. 5(f). Under pressure, the tape 30 with all the chips 20 is bonded to the first target substrate 51 so that the chips 20 in the non-exposed area are transferred to the first target substrate 51.

[0103] In this embodiment, the first target substrate 51 may be a hard, transparent or flexible substrate such as glass, Si, mica, PET, or PO with an adhesion layer. Since the chips 20 in the non-exposed area are taller, they are more likely to come into contact with the first target substrate 51.

[0104] Please refer to FIGS. 5(g) and 5(h). Peel the tape 30 with the exposed-area chips 20 from the first target substrate 51 and attach it to the glass substrate 40. Then irradiate it with ultraviolet light until the tape 30 is completely de-stickified.

[0105] In this embodiment, since the chips 20 in the non-exposed area are taller and are more likely to adhere to the first target substrate 51, after the tape 30 is peeled off, the exposed-area chips 20 will be peeled off from the first target substrate 51 together with the tape 30, while the non-exposed area chips 20 will be transferred to the first target substrate 51.

[0106] Further, attach the tape 30 with the exposed-area chips 20 to a clean glass substrate 40 and irradiate it with ultraviolet light of 365 nm and 20 mw / cm 2 for a duration greater than or equal to 3 s, so that the tape 30 is completely de-stickified.

[0107] Please refer to FIGS. 5(i) and 5(j). Attach the completely de-stickified tape 30 with the exposed-area chips 20 to the second target substrate 52 to transfer the exposed-area chips 20 to the second target substrate 52.

[0108] In this embodiment, the second target substrate 52 may have an adhesion layer. The second target substrate 52 may be a hard, transparent or flexible substrate such as glass, Si, mica, PET, or PO. Due to the function of the adhesion layer and the fact that the tape 30 has been completely de-stickified, when the tape 30 is peeled off from the second target substrate 52, the exposed-area chips 20 will be transferred to the second target substrate 52.

[0109] In this embodiment, an optical mask is introduced to selectively irradiate the chips 20 to be transferred. Using the glass substrate 40 as a temporary substrate can also ensure that the ultraviolet light is accurately projected onto the area that needs to be exposed. Thus, the height difference of the chips 20 caused by polymer growth can be utilized to achieve high-precision and selective transfer of the micro-chips 20.

[0110] In addition, glass can limit the maximum volume expansion of the polymer in space, enabling the chips to be better embedded in the polymer and not be peeled off during the selective transfer process.

[0111] In the selective transfer solution provided in this embodiment, among them, the chips in the exposed area are not peeled off because they are embedded in the polymer, while the chips in the unexposed area are peeled off because they are not embedded in the polymer.

[0112] In this embodiment, the following lists two specific implementation cases to further introduce the above-mentioned selectively transfer method.

[0113] Implementation case three:

[0114] Combine photolithography with dry and wet etching processes to fabricate a GaN chip array to be transferred with weak bonding force. Use a Si<111>-GaN substrate, the size of the GaN chips is 50um*80um, the number is 50*50, and the pitch of the points at the center of the GaN chips is 150um.

[0115] Completely attach the uv tape 30 to the GaN chips to be transferred on the Si substrate. A roller device combined with a vacuum setting can be used to ensure that there are no bubbles between the tape 30 and the Si substrate.

[0116] Peel off the tape 30 on the Si substrate and strip the GaN chips from the Si substrate together.

[0117] Apply pressure evenly to attach the tape 30 with GaN chips to a clean glass substrate 40, and use an optical mask (such as Figure 6 the heart shape in the upper left corner), and use ultraviolet light to perform selective exposure treatment on the GaN chip array. The wavelength of the ultraviolet light can be 365nm, and the output power can be 20mw / cm 2 , and the exposure time can be 0.6s - 1.5s. At this time, as Figure 7 shown, due to the mechanism of photoresponsive polymer growth, the GaN chips in the exposed area and the unexposed area of the GaN chips form a height difference of about 1.6um. The GaN chips in the exposed area are lower, and the GaN chips in the unexposed area are higher.

[0118] Apply pressure evenly to attach the exposed tape 30 to the first target substrate 51. The first target substrate 51 can have an adhesion layer, such as the adhesion layer on a uv PET commercial tape.

[0119] After peeling off the tape 30, the GaN chips in the unexposed area are higher and are more likely to come into contact with the first target substrate 51, so they are transferred to the first target substrate 51, while the GaN chips in the exposed area remain on the tape 30, as Figure 6 shown in the upper right side and Figure 6 the lower left side of

[0120] As shown Figure 6 in the lower right side is a schematic diagram of the GaN chip remaining on the tape 30. Further, the tape 30 with the GaN chip having an exposure area is bonded to a clean glass substrate 40, and ultraviolet light with a wavelength of 365 nm and an intensity of 20 mw / cm 2 is used to expose for 3 s or more until the tape 30 is completely demagnetized.

[0121] Finally, the completely demagnetized tape 30 is bonded to the second target substrate 52 with an adhesive layer, and the remaining GaN chips can be transferred to the second target substrate 52. Among them, the second target substrate 52 is the final substrate, which can be a transparent glass plate with an adhesive layer, and the adhesive layer can be su8-2002 with a thickness of 2 um.

[0122] Case 4:

[0123] Combining photolithography with dry and wet etching processes to fabricate a u-led blue light array to be transferred with weak bonding force: Si<111> substrate, the size of the u-led is 50 um * 80 um, the center point spacing of the u-led is 150 um, and the tether structure.

[0124] The uv tape 30 is perfectly bonded to the u-led on the Si substrate. A roller device combined with a vacuum device can be used to ensure that there are no bubbles between the tape 30 and the Si substrate during bonding.

[0125] The uv tape 30 is peeled off, and the u-led chips are peeled off from the Si substrate together.

[0126] Apply pressure evenly to bond the tape 30 with the u-led chips to a clean glass substrate 40. Introduce an optical mask (such as the arrow shape shown in Figure 8 or the LED letter shape shown in Figure 9 ), and use ultraviolet light to selectively expose the u-led chip array. The wavelength of the ultraviolet light can be 365 nm, and the output power can be 20 mw / cm 2 , and the exposure time can be 0.6 s - 1.5 s. In addition, a height difference is formed between the exposed u-led and the unexposed u-led.

[0127] Apply pressure evenly to bond the exposed tape 30 to the first target substrate 51, and the first target substrate 51 has an adhesive layer, which can be the adhesive layer on a uv PET commercial tape.

[0128] Peel off the tape 30. Since the unexposed u-led is higher and easier to contact the first target substrate 51, the unexposed u-led is transferred to the first target substrate 51, while the exposed u-led remains on the tape 30.

[0129] The chip transfer method provided in this embodiment uses the glass substrate 40 as a temporary substrate, which can achieve an oxygen-free environment. The tape 30 is an anaerobic pressure-sensitive adhesive polymer, and combined with the irradiation of ultraviolet light, it can quickly reduce the viscosity, greatly shortening the transfer process time. Moreover, it can also improve the yield of the transfer. When realizing the transfer of a 4-inch wafer level, the yield can reach 99.9%.

[0130] In addition, in this embodiment, further utilizing the height difference of the chip 20 brought about by the photoinduced polymer growth, the high-precision selective transfer of the micro-chip 20 can be realized.

[0131] Another embodiment of the present application also provides a method for manufacturing a Micro-LED display device, including the transfer of chips and the fabrication of chips. Among them, the chip transfer process can be realized by using the chip transfer method shown in the above embodiment, so as to obtain chips 20 with a high yield and improve the display effect of the Micro-LED display device.

[0132] Another embodiment of the present application also provides a Micro-LED display device, which includes a display panel, and the display panel can be fabricated according to the method for manufacturing a Micro-LED display device in the above embodiment.

[0133] The Micro-LED display device provided in this embodiment is fabricated by using the above manufacturing method, and thus has the advantages of high yield and good display effect.

[0134] In summary, the embodiments of the present application provide a chip transfer method, a Micro-LED display device and a manufacturing method. In this chip transfer method, the tape 30 is attached to the original substrate 10 with the chip 20 under the action of pressure, the tape 30 and the chip 20 are peeled off from the original substrate 10 together, and under the action of pressure, the tape 30 with the chip 20 is attached to the provided glass substrate 40 to exclude air. The viscosity of the tape 30 is weakened by ultraviolet light irradiation, and finally the tape 30 with the weakened viscosity and the chip 20 is attached to the target substrate 50 to transfer the chip 20 to the target substrate 50. In this solution, the viscosity of the tape 30 is weakened by means of ultraviolet light irradiation, and a temporary glass substrate 40 is introduced during the viscosity reduction, so that the tape 30 quickly reduces viscosity in an oxygen-free environment, shortening the process time, reducing the process cost, and improving the transfer yield and accuracy.

[0135] The above is only a specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed by the present invention should be covered within the protection scope of the present invention. Therefore, the protection scope of the present invention should be subject to the protection scope of the claims.

Claims

1. A chip transfer method, characterized in that, The method includes: providing a raw substrate with a plurality of chips to be transferred arranged in an array thereon; attaching a tape to the raw substrate and the chips under pressure; peeling the tape and the chips from the raw substrate; under pressure, attaching the tape with the chips to a provided glass substrate to expel air, irradiating with ultraviolet light to weaken the adhesiveness of the tape, and attaching the tape with weakened adhesiveness and the chips to a target substrate to transfer the chips to the target substrate; The step of attaching the tape with the chips to a provided glass substrate to expel air, irradiating with ultraviolet light to weaken the adhesiveness of the tape, and attaching the tape with weakened adhesiveness and the chips to a target substrate to transfer the chips to the target substrate includes: attaching the tape with the chips to a provided glass substrate to expel air, irradiating the chips with ultraviolet light using an optical mask to obtain the chips in the exposed area and the chips in the non-exposed area, wherein the height of the chips in the exposed area is lower than the height of the chips in the non-exposed area; using the tape to sequentially transfer the chips in the non-exposed area to a first target substrate and transfer the chips in the exposed area to a second target substrate; The step of using the tape to sequentially transfer the chips in the non-exposed area to a first target substrate and transfer the chips in the exposed area to a second target substrate includes: under pressure, attaching the tape with all the chips to the first target substrate to transfer the chips in the non-exposed area to the first target substrate; peeling the tape with the chips in the exposed area from the first target substrate and attaching it to the glass substrate, and irradiating with ultraviolet light until the tape is completely de-adhered; attaching the tape with the completely de-adhered chips in the exposed area to the second target substrate to transfer the chips in the exposed area to the second target substrate.

2. The chip transfer method according to claim 1, wherein The side of the target substrate in contact with the chips has an adhesion layer.

3. The chip transfer method according to claim 1, wherein The step of attaching the tape to the raw substrate and the chips under pressure includes: applying pressure to the tape and the raw substrate in the vertical direction; using a vacuum device to evacuate the air between the tape and the raw substrate to attach the tape to the raw substrate.

4. The chip transfer method according to claim 1, wherein The step of attaching the tape to the raw substrate and the chips under pressure includes: using a roller device to apply uniform pressure to the tape in sequence to make the tape and the raw substrate adhere to each other in a bubble-free state.

5. The chip transfer method according to claim 1, wherein Before the step of attaching the tape to the raw substrate and the chips under pressure, the method further includes: immersing the raw substrate with the chips in an etching solution to form a weak bonding force between the chips and the raw substrate.

6. The chip transfer method according to claim 1, wherein The irradiation wavelength of the ultraviolet light is 320 nm to 400 nm.

7. A method for manufacturing a Micro-LED display device, characterized in that, including chip transfer and chip array fabrication, wherein chip transfer is performed using the chip transfer method according to any one of claims 1-6.

8. A Micro-LED display device, characterized in that, Fabricated by using the Micro-LED display device manufacturing method according to claim 7.

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