Method for Transferring Micro Flip Chip

Abstract

The present application provides a method for transferring a micro flip chip, comprising the steps of: providing a driving substrate; providing a temporary substrate on one surface of which a plurality of micro flip chips are bonded, forming a first bonding member made of a conductive adhesive on the surface of the micro flip chips away from the temporary substrate; transferring the plurality of micro flip chips to the driving substrate, and the first bonding member connects the second electrical connection member of the micro flip chips to the first electrical connection member of the driving substrate; detecting the plurality of micro flip chips, determining the position of the defective chips on the driving substrate where the defective chips are located; and irradiating the first bonding member at the position of the defective chips with a laser to remove the defective chips. The above method can ensure stable bonding between the micro flip chips and the driving substrate, avoid damage caused by laser irradiation to the first electrical connection member, and allow the original bonding welded portion to continue to be used, and has a high efficiency in removing the defective chips.

Description

Technical Field

[0001] This application claims the priority of a Chinese patent application with an application number of 202210922999.X and an invention title of "Method for Transferring Micro Flip Chips", which was filed with the China National Intellectual Property Administration on August 2, 2022, and the entire content thereof is incorporated herein by reference.

[0002] This application relates to the technical field of chip assembly, and specifically, to a method for transferring micro flip chips.

Background Art

[0003] Micro-LED display technology refers to a display technology that assembles self-emitting Micro-LEDs as light-emitting pixel units onto a driving substrate to form a high-density LED array. Since Micro-LED chips have characteristics such as small size, high integration, and self-emission, compared with LCDs and OLEDs, they have greater advantages in terms of brightness, resolution, contrast, energy consumption, service life, response speed, and thermal stability, and are regarded as one of the most promising new display and light-emitting devices. In the current industry, an important breakthrough that Micro-LED display technology is generally expected to replace conventional OLED and liquid crystal display technologies is display products for applications in medium and low-resolution (PPI) display scenarios, such as small wearable devices, TV displays, and ultra-large display walls. For medium and low PPI display products, after manufacturing the Micro-LED chip wafer and the driving substrate, it is necessary to transfer millions or even tens of millions of Micro-LED chips to the driving substrate using mass transfer technology, and electrically connect the first electrical connection member of the driving substrate and the second electrical connection member of the Micro-LED chip.

[0004] The transfer yield is one of the main technical challenges in the mass transfer process. Even if the overall transfer yield reaches 99.99%, when transferring one 8K TV, more than half a million defective chips need to be repaired, and the defective chips are almost randomly distributed. Among various Micro-LED die repair technologies, the selective laser repair technology is the most potential technology that can achieve mass production. This technology can quickly scan by a laser scanner and precisely control in combination with a displacement platform, and can efficiently remove a large number of random defective chips.

[0005] However, it is common that the laser emitted by the selective laser repair technology causes irreversible damage to the first electrical connection member of the driving substrate. As a result, it cannot be used for connecting replacement chips, and furthermore, the original bonding position cannot be reused.

Summary of the Invention

Problems to be Solved by the Invention

[0006] Therefore, the technical problem to be solved by this application is to overcome the drawback that the original bonding position cannot be reused after removing defective chips in the conventional selective laser repair technology, and to provide a method for transferring micro flip chips.

Means for Solving the Problems

[0007] This application provides a step of providing a driving substrate with a first electrical connection member formed on one side surface, Providing a temporary substrate having a plurality of micro flip chips adhered to a surface on one side, wherein a second electrical connection member is formed on a surface of the micro flip chip on a side away from the temporary substrate; forming a first bonding member, the material of which is a conductive adhesive, on a surface of the second electrical connection member of the micro flip chip on a side away from the temporary substrate; transferring the plurality of micro flip chips to the driving substrate, and connecting the first bonding member to the second electrical connection member of the micro flip chip and the first electrical connection member; detecting the plurality of micro flip chips and determining a vanishing point position of a defective chip on the driving substrate; and irradiating a laser to the first bonding member at the vanishing point position to remove the defective chip. A method for transferring micro flip chips is provided, which includes the above steps.

[0008] Optionally, the step of forming a first bonding member on a surface of the second electrical connection member of the micro flip chip on a side away from the temporary substrate includes coating a conductive adhesive on a surface of the second electrical connection member of the micro flip chip on a side away from the temporary substrate, or dipping a surface of the second electrical connection member of the micro flip chip on a side away from the temporary substrate into a conductive adhesive solution, and removing the micro flip chip having a surface of one side of the second electrical connection member coated with the conductive adhesive from the conductive adhesive solution.

[0009] Optionally, the thickness of the first bonding member is 2 μm to 10 μm.

[0010] Optionally, the method for transferring micro flip chips further includes providing a replacement chip having a second electrical connection member formed on a surface on one side; forming a second bonding member, the material of which is a conductive adhesive, on a surface of one side of the second electrical connection member of the replacement chip; after removing the defective chip, transferring the replacement chip to the vanishing point position, and connecting the second bonding member to the second electrical connection member of the replacement chip and the first electrical connection member at the vanishing point position.

[0011] Optionally, the step of forming the second bonding member on one side surface of the second electrical connection member of the replacement chip includes coating a conductive adhesive on one side surface of the second electrical connection member of the replacement chip, or dipping one side surface of the second electrical connection member of the replacement chip into a conductive adhesive solution, and removing the replacement chip having the one side surface of the second electrical connection member coated with the conductive adhesive from the conductive adhesive solution.

[0012] Optionally, the process of transferring the replacement chip to the vanishing point position includes a laser transfer process and an elastic seal transfer process.

[0013] Optionally, the thickness of the second bonding member is 2 μm to 10 μm.

[0014] Optionally, the conductive adhesive includes an organic adhesive solution and conductive particles at the micro-nano level uniformly dispersed in the organic adhesive solution, and the volume fraction of the conductive particles in the conductive adhesive is 10% to 40%.

[0015] Optionally, the conductive adhesive includes an isotropic conductive adhesive.

[0016] Optionally, the conductive particles include metal particles or composite metal particles, and the composite metal particles include a particle body and a metal layer wrapping the particle body.

[0017] Optionally, the materials of the metal particles include silver, nickel, and copper, the material of the metal layer includes silver, and the materials of the particle body include at least one of nickel, copper, and carbon nanotubes.

[0018] Optionally, the conductive particles are sheet-shaped, the size of the conductive particles in the longitudinal direction is smaller than the size of the conductive particles in the transverse direction, and the size in the transverse direction is 1 μm to 20 μm.

[0019] Optionally, the material of the organic adhesive liquid is a thermosetting material or a thermoplastic material.

[0020] Optionally, the material of the organic adhesive liquid is a thermosetting material.

[0021] Optionally, the thermosetting material includes an epoxy resin, a cyanate ester resin, and a polyimide.

[0022] Optionally, the energy density of the laser is 100 mJ / cm 2 ~800 mJ / cm 2 is.

[0023] Optionally, the laser is an ultraviolet laser.

[0024] Optionally, the wavelength of the laser is 240 nm to 380 nm.

[0025] Optionally, the process of transferring the plurality of micro flip chips to the driving substrate includes a laser transfer process and an elastic seal transfer process.

[0026] Optionally, the first electrical connection member includes contact electrodes arranged in an array on one surface of the driving substrate and first bumps on the surface of the contact electrodes away from the driving substrate. The second electrical connection member is the electrode of the micro flip chip, or the first electrical connection member includes the electrode of the micro flip chip and a second bump covering the electrode.

[0027] Optionally, the micro flip chip includes a Micro-LED chip.

Advantages of the Invention

[0028] The technical solution of the present application has the following advantages.

[0029] 1. In the method for transferring a micro flip chip according to the present application, the conductive adhesive is used as a first bonding member for electrically connecting the micro flip chip and the driving substrate. While the conductive adhesive can ensure stable bonding between the micro flip chip and the driving substrate, the organic material in the conductive adhesive at the extinction point absorbs laser energy and vaporizes during laser irradiation. Due to the airflow caused by the vaporization of the organic material, the defective chip and the driving substrate are separated. Separation between the defective chip and the substrate is achieved at the moment when the laser irradiates the conductive adhesive, and the energy of the laser is mainly absorbed and released by the organic material. In this way, the energy actually acting on the first electrical connection member of the driving substrate is low, avoiding damage to the first electrical connection member caused by laser irradiation, enabling continued use of the original bonding and welding part, and having a high removal efficiency for defective chips.

[0030] 2. In the method for transferring a micro flip chip according to the present application, the micro flip chip includes a Micro-LED chip. In the above method for transferring a micro flip chip, the first electrical connection member can be used for the electrical connection of the replacement chip, whereby the original bonding position can be used for image display, which is advantageous for improving the display effect of Micro-LED display technology.

[0031] 3. In the method for transferring a micro flip chip according to the present application, by limiting the thickness of the first bonding member to 2 μm to 10 μm, stable bonding between the micro flip chip and the driving substrate is ensured, while shortening the time for the laser to act on the first bonding member and ensuring the removal efficiency of defective chips.

[0032] 4. In the method for transferring a micro flip chip according to the present application, by limiting the volume fraction of the conductive particles in the conductive adhesive to 10% to 40%, stable bonding between the micro flip chip and the driving substrate is ensured, and it is advantageous for the electrical connection effect between the micro flip chip and the driving substrate.

[0033] 5. In the method for transferring a micro flip chip according to the present application, the material of the organic adhesive liquid is selectively a thermosetting material, that is, the organic materials in the first bonding member and the second bonding member are selectively thermosetting materials. The thermosetting material obtains a stable structure after the first heat curing and will not soften due to too high environmental temperature during use, ensuring the stable bonding between the micro flip chip and the driving substrate.

[0034] To more clearly explain the specific embodiments of the present application or the technical solutions in the prior art, the drawings used for the description of the specific embodiments or the prior art will be briefly described below. Obviously, the drawings described below are some embodiments of the present application, and those skilled in the art can obtain other drawings based on these drawings without creative effort.

Brief Description of the Drawings

[0035]

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Embodiments for Carrying Out the Invention

[0036] As described in the background art, when defective chips are removed by the conventional selective laser repair technology, the original bonding positions cannot be reused.

[0037] Specifically, usually, bonding between the micro flip chip and the driving substrate is realized by alloying the first electrical connection member of the driving substrate and the second electrical connection member of the micro flip chip. Exemplarily, as shown in FIG. 1, the first electrical connection member includes a contact electrode 11' located on one surface of the driving substrate 1', and a first bump 13' located on the surface of the contact electrode 11' away from the driving substrate 1'. The first electrical connection member includes an electrode (not shown) of the micro flip chip 3' and a second bump 31' covering the electrode. An alloy is formed at the connection part of the first bump 13' and the second bump 31', and a laser 5' is irradiated on the alloy part. As shown in FIG. 2, after the alloy is irradiated with the laser for a certain period of time, the alloy melts and is damaged, whereby the defective chip 32' falls off. At this time, the first electrical connection member is not in its original form, that is, the form of the first electrical connection member is damaged and it cannot be used for connecting the replacement chip to meet the requirements of bonding repair. That is, the original bonding position cannot be reused. Also, because the melting point of the alloy is high, it takes a relatively long time until welding cracks occur due to laser irradiation, and the removal efficiency of defective chips is limited to a certain extent.

[0038] Therefore, referring to FIG. 3, this embodiment Step S1 of providing a driving substrate with a first electrical connection member formed on one surface; Step S2 of providing a temporary substrate with a plurality of micro flip chips adhered to one surface, wherein a second electrical connection member is formed on the surface of the micro flip chip away from the temporary substrate; Step S3 of forming a first bonding member, the material of which is a conductive adhesive, on the surface of the second electrical connection member of the micro flip chip away from the temporary substrate; Step S4 of transferring a plurality of the micro flip chips to the driving substrate, and the first bonding member connecting the second electrical connection member of the micro flip chip and the first electrical connection member; Step S5 of detecting a plurality of the micro flip chips and determining the vanishing point position of the defective chip on the driving substrate; Provided is a method for transferring a micro flip chip, including step S6 of irradiating a laser to the first bonding member at the vanishing point position to remove the defective chip.

[0039] In the above method for transferring a micro flip chip, the conductive adhesive is used as a first bonding member for electrically connecting the micro flip chip and the driving substrate. While the conductive adhesive can ensure stable bonding between the micro flip chip and the driving substrate, the organic material in the conductive adhesive at the vanishing point position absorbs laser energy and vaporizes during laser irradiation. Due to the airflow caused by the vaporization of the organic material, the separation between the defective chip and the driving substrate is realized. The separation between the defective chip and the substrate is realized at the moment when the laser irradiates the conductive adhesive, and the energy of the laser is mainly absorbed and released by the organic material. In this way, the energy actually acting on the first electrical connection member of the driving substrate is low, avoiding damage to the first electrical connection member caused by laser irradiation, enabling the original bonding and welding part to be continuously used, and having a high removal efficiency of the defective chip.

[0040] The specific principle of peeling the defective chip by laser irradiation is as follows. When the laser irradiates the first bonding member, the organic material in the first bonding member absorbs photons, and due to the photons, the chemical bonds of the organic polymer are broken to form organic small molecules. Since the photon density in the laser is high, the cutting speed of the chemical bonds in the first bonding member exceeds the recombination speed of the chemical bonds. In this way, the organic polymer in the first bonding member is rapidly decomposed into organic small molecules. Due to the presence of these organic small molecules, the specific volume of the first bonding member rapidly increases, the pressure rapidly increases, the volume rapidly expands, and finally a body explosion occurs, the defective chip is peeled off, and excessive heat is taken away.

[0041] Furthermore, the micro flip chip includes a Micro-LED chip. In the method for transferring the micro flip chip, the first electrical connection member can be used for electrical connection of the replacement chip, so that the original bonding position can be used for image display, which is advantageous for improving the display effect of the Micro-LED display technology.

[0042] Specifically, the first electrical connection member includes contact electrodes arranged in an array on one surface of the driving substrate and first bumps on the surface of the contact electrodes away from the driving substrate. The second electrical connection member is an electrode of the micro flip chip, or the first electrical connection member includes an electrode of the micro flip chip and second bumps covering the electrode.

[0043] Hereinafter, taking the case where the second electrical connection member includes an electrode of the micro flip chip and second bumps covering the electrode as an example, the technical solution of the present application will be clearly and completely described with reference to FIGS. 4 to 16.

[0044] Referring to FIG. 4, a driving substrate 1 is provided on one surface of which contact electrodes 11 arranged in an array are formed.

[0045] Referring to FIG. 5, first initial bumps 12 are formed on the surface of the contact electrodes 11 away from the driving substrate 1.

[0046] Specifically, the material of the first initial bumps 12 includes at least one of In, Sn, Ag, Au, and Cu, but is not limited thereto.

[0047] Referring to FIG. 6, reflow soldering is performed on the first initial bumps 12 to make the first initial bumps 12 into first bumps 13.

[0048] Referring to FIG. 7, a temporary substrate 2 is provided on one surface of which an adhesive layer 21 is formed.

[0049] Referring to FIG. 8, an array of micro flip chips 3 is classified and transferred onto a temporary substrate 2, the micro flip chips 3 are adhered to an adhesive layer 21, and both the electrodes of the micro flip chips 3 and the second bumps 31 covering the electrodes are separated from the temporary substrate 2, and the electrodes and the second bumps 31 constitute a second electrical connection member.

[0050] Referring to FIGS. 9 to 10, a first bonding member 4 made of a conductive adhesive is formed on the surface of the second electrical connection member of the micro flip chip 3 on the side away from the temporary substrate 2.

[0051] Specifically, the step of forming the first bonding member 4 on the surface of the second electrical connection member of the micro flip chip 3 on the side away from the temporary substrate 2 includes, referring to FIG. 9, dipping the surface of the second bumps 31 of the micro flip chip 3 on the side away from the temporary substrate into a conductive adhesive liquid 41, and referring to FIG. 10, removing the micro flip chip 3 with the conductive adhesive coated on one side surface of the second bumps 31 from the conductive adhesive liquid 41.

[0052] Furthermore, the conductive adhesive includes an organic adhesive liquid and conductive particles at the micro-nano level uniformly dispersed in the organic adhesive liquid. The material of the organic adhesive liquid may be a thermosetting material or a thermoplastic material such as epoxy resin, cyanate ester resin, polyimide acrylate, silica gel, etc. The conductive particles include metal particles or composite metal particles. The composite metal particles include a particle body and a metal layer wrapping the particle body. The material of the metal particles includes, but is not limited to, silver, nickel, and copper. The material of the metal layer includes silver. The material of the particle body includes at least one of nickel, copper, and carbon nanotubes, but is not limited thereto. Do, Shi

[0053] ​As a selective embodiment, the material of the organic adhesive liquid is a thermosetting material, that is, the organic material in the first bonding member 4 is selectively a thermosetting material. The thermosetting material obtains a stable structure after the first heat curing and will not soften due to too high environmental temperature during use, ensuring the stable bonding of the micro flip chip 3 and the driving substrate 1.

[0054] Furthermore, the volume fraction of the conductive particles in the conductive adhesive is 10% - 40%. Exemplarily, the volume fraction of the conductive particles may be 10%, 15%, 20%, 25%, 30%, 35% or 40%. If the volume fraction of the conductive particles is too small, the volume fraction of the organic adhesive liquid will be too large, which is advantageous for the stable bonding of the micro flip chip 3 and the driving substrate 1, but the conductivity of the bonding member will deteriorate. As a result, the effect of the electrical connection between the micro flip chip 3 and the driving substrate 1 is limited. If the volume fraction of the conductive particles is too large, the volume fraction of the organic adhesive liquid will be too small, which is advantageous for the effect of the electrical connection between the micro flip chip 3 and the driving substrate 1, but not advantageous for the stability of the connection between the micro flip chip 3 and the driving substrate 1. By limiting the volume fraction of the conductive particles in the conductive adhesive to 10% - 40%, the stable bonding of the micro flip chip 3 and the driving substrate 1 is ensured, and it is advantageous for the effect of the electrical connection between the micro flip chip 3 and the driving substrate 1.

[0055] Optionally, the conductive particles are sheet-shaped, the size of the conductive particles in the longitudinal direction is smaller than the size of the conductive particles in the transverse direction, and the size in the transverse direction is 1μm - 20μm. Exemplarily, the size of the conductive particles in the transverse direction is 1μm, 2.5μm, 5μm, 7.5μm, 10μm, 12.5μm, 15μm, 17.5μm or 20μm.

[0056] Furthermore, the conductive adhesive may select an isotropic conductive adhesive or an anisotropic conductive adhesive. Optionally, the conductive adhesive selects an isotropic conductive adhesive, and the isotropic conductive adhesive can ensure the electrical connection ability of the first bonding member 4.

[0057] It should be understood that the first bonding member 4 may be formed by coating the surface of the second bump 31 with a conductive adhesive, or the first bonding member 4 may be formed by other micro-nano processing methods.

[0058] Furthermore, the thickness of the first bonding member 4 is 2 μm to 10 μm. Exemplarily, the thickness of the first bonding member 4 may be 2 μm, 3 μm, 4 μm, 5 μm, 6 μm, 7 μm, 8 μm, 9 μm, or 10 μm. If the first bonding member 4 is too thin, the stability of the adhesion between the micro flip chip 3 and the driving substrate 1 cannot be ensured. If the first bonding member 4 is too thick, it is necessary to irradiate the first bonding member 4 with the laser 5 for a long time to realize the separation of defective chips, and the removal efficiency of defective chips decreases. By limiting the thickness of the first bonding member 4 to 2 μm to 10 μm, stable bonding between the micro flip chip 3 and the driving substrate 1 is ensured, the time for the laser 5 to act on the first bonding member 4 is shortened, and the removal efficiency of defective chips is ensured.

[0059] Referring to FIGS. 11 to 12, a plurality of the micro flip chips 3 are transferred onto the driving substrate 1, and the first bonding member 4 connects the second electrical connection member and the first electrical connection member of the micro flip chip 3, bonding the micro flip chip 3 and the driving substrate 1 integrally.

[0060] Specifically, referring to FIG. 11, the temporary substrate 2 and the driving substrate 1 are arranged opposite to each other, and the first bonding member 4 on one side of the micro flip chip 3 is bonded to the first bump 13 on the surface of the driving substrate 1. Referring to FIG. 12, the temporary substrate 2 is removed, and the adhesive layer 21 on the surface of one side of the temporary substrate 2 is also removed. The process of transferring a plurality of the micro flip chips 3 onto the driving substrate 1 includes, but is not limited to, a laser transfer process and an elastic seal transfer process.

[0061] After integrally bonding the micro flip chip 3 and the drive substrate 1, a plurality of micro flip chips 3 on the drive substrate 1 are detected, and the vanishing point position of the defective chip on the drive substrate 1 is determined. Specifically, the detection includes optical detection and electrical detection. After determining the vanishing point position of the defective chip on the drive substrate 1, the coordinate value of the drive substrate 1 at the vanishing point position is obtained, and the coordinate system uses the edge of the drive substrate 1 as the coordinate axis.

[0062] Referring to FIGS. 13 to 14, the first bonding member 4 at the vanishing point position is irradiated with a laser 5 to remove the defective chip 32.

[0063] Specifically, referring to FIG. 13, the laser 5 is irradiated onto the first bonding member 4 through the defective chip 32, and the dimension of the laser spot is adapted to the dimension of the micro flip chip 3, that is, the dimension of the laser spot is equal to or larger than the dimension of the micro flip chip and covers only one micro flip chip. Exemplarily, a plurality of micro flip chips are arranged in an array, the pitch between the central axis lines of adjacent micro flip chips is the same, the projection of the micro flip chip array on the substrate is rectangular (a×b). In this case, the dimension of the laser spot is equal to or larger than a×b and equal to or smaller than (Pitch×2 - a)×(Pitch×2 - b). When a = 15μm, b = 25μm, and Pitch = 35μm, the dimension of the laser spot is equal to or larger than 15μm×25μm and equal to or smaller than 55μm×45μm.

[0064] Furthermore, the energy density of the laser 5 is 100 mJ / cm 2 ~800 mJ / cm 2 . Exemplarily, the energy density of the laser 5 may be 100 mJ / cm 2 , 200 mJ / cm 2 , 300 mJ / cm 2 , 400 mJ / cm 2 , 500 mJ / cm 2 , 600 mJ / cm 2 , 700 mJ / cm 2 or 800 mJ / cm 2 .

[0065] Furthermore, the laser 5 may be an ultraviolet laser. The organic material in the first bonding member 4 has a strong absorption effect on ultraviolet rays, and thus the peeling efficiency of the defective chip 32 is high. Optionally, the wavelength of the laser 5 is 240 nm to 380 nm. Exemplarily, the wavelength of the laser 5 may be 248 nm, 266 nm, 280 nm, 355 nm, 365 nm, or 375 nm.

[0066] Furthermore, the laser 5 is a single-pulse laser, and the pulse width is on the order of nanoseconds or picoseconds.

[0067] Referring to FIG. 15, a replacement chip 6 is provided on which the second electrical connection member is formed on one side surface, and a second bonding member 7 whose material is a conductive adhesive is formed on one side surface of the second electrical connection member of the replacement chip 6. The replacement chip 6 and the original micro flip chip at the vanishing point position have the same structure.

[0068] Specifically, the step of forming the second bonding member 7 on one side surface of the second electrical connection member of the replacement chip 6 includes dipping one side surface of the second bump of the replacement chip 6 into the conductive adhesive liquid 41 and removing the replacement chip 6 from the conductive adhesive liquid 41 after the one side surface of the second bump is coated with the conductive adhesive. The second bonding member 7 may be formed by coating the conductive adhesive on one side surface of the second bump of the replacement chip 6. The method of forming the second bonding member 7 includes but is not limited to the above method.

[0069] Furthermore, the second bonding member 7 can use the same material as the first bonding member 4, which will not be described in detail here.

[0070] Furthermore, the thickness of the second bonding member 7 is 2 μm to 10 μm. Exemplarily, the thickness of the second bonding member 7 may be 2 μm, 3 μm, 4 μm, 5 μm, 6 μm, 7 μm, 8 μm, 9 μm, or 10 μm. By limiting the thickness of the second bonding member 7 to 2 μm to 10 μm, stable bonding between the micro flip chip 3 and the driving substrate 1 is ensured, and after the laser acts on the second bonding member 7, sufficient airflow is generated to ensure the removal efficiency of the defective chip 32.

[0071] Referring to FIG. 16, after removing the defective chip 32, the replacement chip 6 is transferred to the vanishing point position, and the second bonding member 7 connects the second electrical connection member of the replacement chip 6 and the first electrical connection member at the vanishing point position.

[0072] Specifically, the process of transferring the replacement chip 6 to the vanishing point position includes, but is not limited to, a laser transfer process and an elastic seal transfer process.

[0073] It should be understood that before removing the defective chip 32, the second bonding member 7 may be formed on the surface of the second bump of the replacement chip 6, and after removing the defective chip 32, the replacement chip 6 may be directly transferred to the vanishing point position, which is advantageous for shortening the time.

[0074] It should be understood that the detection of the micro flip chip of the driving substrate, the removal of the defective chip, and the transfer of the replacement chip constitute an in-situ repair step. After transferring the replacement chip to the vanishing point position, the in-situ repair step can be repeatedly executed until there is no vanishing point on the surface of the driving substrate.

[0075] As is clear, the above embodiments are merely examples for clear explanation and do not limit the embodiments. Those skilled in the art can make various changes and modifications based on the above description. Here, it is not necessary to cover all embodiments, nor is it possible to cover all embodiments. Apparent changes and modifications derived therefrom are still within the protection scope of the present invention. In the description of this application, the terms "first" and "second" are merely for explanation and cannot be understood as indicating or implying corresponding importance.

Explanation of Reference Numerals

[0076] 1 Driving substrate 11 Contact electrode 12 First initial bump 13 First bump 2 Temporary substrate 21 Adhesive layer 3 Micro flip chip 31 Second bump 32 Defective chip 4 First bonding member 41 Conductive adhesive liquid 5 Laser 6 Replacement chip 7 Second bonding member 1’ Driving substrate 11’ Contact electrode 13’ First bump 3’ Micro flip chip 31’ Second bump 32’ Defective chip 5’ Laser

Claims

1. A method for transferring a micro flip chip, comprising: providing a driving substrate having a first electrical connection member formed on one surface thereof, wherein the first electrical connection member includes contact electrodes arranged in an array on one surface of the driving substrate and a first bump on a surface of the contact electrode away from the driving substrate; providing a temporary substrate having a plurality of micro flip chips adhered to one surface thereof, wherein a second electrical connection member is formed on a surface of the micro flip chip away from the temporary substrate, and the second electrical connection member includes an electrode of the micro flip chip and a second bump covering the electrode; forming a first bonding member, the material of which is an electrically conductive adhesive, on a surface of the second electrical connection member of the micro flip chip away from the temporary substrate, wherein the electrically conductive adhesive is an isotropic electrically conductive adhesive; transferring the plurality of micro flip chips to the driving substrate, and connecting the first bonding member to the second electrical connection member of the micro flip chip and the first electrical connection member; detecting the plurality of micro flip chips and determining a vanishing point position of a defective chip on the driving substrate; irradiating a laser on the first bonding member at the vanishing point position to remove the defective chip. A method for transferring a micro flip chip, characterized by the above steps.

2. The step of forming a first bonding member on a surface of the second electrical connection member of the micro flip chip away from the temporary substrate includes: coating an electrically conductive adhesive on a surface of the second bump of the second electrical connection member of the micro flip chip away from the temporary substrate; or, dipping a surface of the second bump of the second electrical connection member of the micro flip chip away from the temporary substrate into an electrically conductive adhesive solution, and removing the micro flip chip from the electrically conductive adhesive solution after the surface of one side of the second bump of the second electrical connection member is coated with the electrically conductive adhesive. The method for transferring a micro flip chip according to claim 1, characterized by the above steps.

3. The thickness of the first bonding member is 2 μm to 10 μm. The method for transferring a micro flip chip according to claim 1, characterized by the above steps.

4. Providing a replacement chip having the second electrical connection member formed on one side surface thereof; Forming a second bonding member, the material of which is a conductive adhesive, on one side surface of the second electrical connection member of the replacement chip; After removing the defective chip, transferring the replacement chip to the vanishing point position, and connecting the second bonding member to the second electrical connection member of the replacement chip and the first electrical connection member at the vanishing point position. The method for transferring a micro flip chip according to any one of claims 1 to 3, further comprising the above steps.

5. The step of forming the second bonding member on one side surface of the second electrical connection member of the replacement chip includes: Coating a conductive adhesive on one side surface of the second bump of the second electrical connection member of the replacement chip; Or, dipping one side surface of the second bump of the second electrical connection member of the replacement chip into a conductive adhesive solution, and removing the replacement chip having the one side surface of the second bump of the second electrical connection member coated with the conductive adhesive from the conductive adhesive solution. The method for transferring a micro flip chip according to claim 4, characterized by including the above steps.

6. The process of transferring the replacement chip to the vanishing point position includes a laser transfer process and an elastic seal transfer process. The method for transferring a micro flip chip according to claim 4, characterized by including the above steps.

7. The thickness of the second bonding member is 2 μm to 10 μm. The method for transferring a micro flip chip according to claim 4, characterized by including the above steps.

8. The conductive adhesive includes an organic adhesive solution and micro / nano-level conductive particles uniformly dispersed in the organic adhesive solution, and the volume fraction of the conductive particles in the conductive adhesive is 10% to 40%. The method for transferring a micro flip chip according to claim 2, characterized by including the above steps.

9. The conductive particles include metal particles or composite metal particles, and the composite metal particles include a particle main body and a metal layer wrapping the particle main body. The method for transferring a micro flip chip according to claim 8, characterized by including the above steps.

10. The material of the metal particles includes silver, nickel, and copper, the material of the metal layer includes silver, and the material of the particle main body includes at least one of nickel, copper, and carbon nanotubes. The method for transferring a micro flip chip according to claim 9, characterized by including the above steps.

11. The conductive particles are sheet-shaped, the size of the conductive particles in the longitudinal direction is smaller than the size of the conductive particles in the transverse direction, and the size in the transverse direction is 1 μm to 20 μm. The method for transferring a micro flip chip according to claim 9, characterized in that.

12. The material of the organic adhesive liquid is a thermosetting material or a thermoplastic material. The method for transferring a micro flip chip according to claim 8, characterized in that.

13. The material of the organic adhesive liquid is a thermosetting material. The method for transferring a micro flip chip according to claim 12, characterized in that.

14. The thermosetting material includes an epoxy resin, a cyanate ester resin, and a polyimide. The method for transferring a micro flip chip according to claim 12 or 13, characterized in that.

15. The energy density of the laser is 100 mJ / cm ２ to 800 mJ / cm ２ The method for transferring a micro flip chip according to claim 1, characterized in that it is so.

16. The laser is an ultraviolet laser. The method for transferring a micro flip chip according to claim 15, characterized in that.

17. The wavelength of the laser is 240 nm to 380 nm. The method for transferring a micro flip chip according to claim 15, characterized in that.

18. The process of transferring a plurality of the micro flip chips to the driving substrate includes a laser transfer process and an elastic seal transfer process. The method for transferring a micro flip chip according to claim 1, characterized in that.

19. The micro flip chip includes a Micro-LED chip. The method for transferring a micro flip chip according to any one of claims 1 to 3, characterized in that.

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