Micro light emitting device transfer method

Abstract

Provided is a micro light emitting device transfer method comprising the steps of: providing a first substrate having light emitting devices arranged in a grid attached thereto; transferring the light emitting devices on the first substrate to a second substrate, one line at a time, wherein, in transferring to the second substrate, the first substrate and the second substrate are relatively moved every time one line of the light emitting devices extending in a first direction is transferred, in order to adjust the spacing in a second direction of the one line of the light emitting devices extending in the first direction; and transferring the light emitting devices on the second substrate to a third substrate, wherein, the transferring to the third substrate is carried out so as to adjust the spacing in the first direction of one line of the light emitting devices extending in the second direction.

Description

Transfer method of micro luminescent elements

[0001] The present invention relates to a transfer method for micro light-emitting elements, and more particularly, to a transfer method for micro light-emitting elements that can improve productivity because the pitch of light-emitting elements can be changed through a simple process.

[0002] As electrical and electronic technologies rapidly advance, the integration of various individual components with different technical characteristics may be necessary to meet the needs of new eras and diverse consumers.

[0003] Accordingly, a transfer method capable of manufacturing individual elements (or individual components) manufactured based on different technologies on a source substrate and then transferring (or transferring) them in large quantities to a wiring substrate (or display substrate), i.e., a target substrate (or destination substrate), without damage, is very important.

[0004] The technical problem to be achieved by the present invention is to provide a method for transferring micro light-emitting elements, which can improve productivity because the pitch of light-emitting elements can be changed through a simple process.

[0005] The present invention provides a method for transferring micro light-emitting elements, comprising the steps of: providing a first substrate to which light-emitting elements arranged in a grid are attached; transferring light-emitting elements on the first substrate one by one to a second substrate, the step of relatively moving the first substrate and the second substrate each time a line of light-emitting elements extending in a first direction is transferred to the second substrate so as to adjust the spacing between the line of light-emitting elements extending in a first direction in a second direction; and transferring light-emitting elements on the second substrate to a third substrate, the step of transferring light-emitting elements to the third substrate so as to adjust the spacing between the line of light-emitting elements extending in the second direction in the first direction.

[0006] In some embodiments, the light emitting elements may be attached to the first substrate via a photosensitive adhesive layer.

[0007] In some embodiments, in the step of transferring the light-emitting elements on the first substrate one by one to the second substrate, the light-emitting elements on the first substrate can be transferred to the second substrate by photodecomposition of the photosensitive adhesive layer.

[0008] In some embodiments, the second substrate includes a transfer adhesive layer, and in the step of transferring the light emitting elements on the first substrate one by one to the second substrate, the light emitting elements on the first substrate can be transferred onto the transfer adhesive layer of the second substrate.

[0009] In some embodiments, the light emitting elements are arranged at a first pitch in a second direction on the first substrate and at a second pitch in a second direction on the second substrate, wherein the second pitch may be greater than the first pitch.

[0010] In some embodiments, the second pitch may not be an integer multiple of the first pitch.

[0011] In some embodiments, the step of transferring the light emitting elements on the second substrate to the third substrate includes the step of transferring the light emitting elements on the second substrate to an intermediate substrate; and the step of transferring the light emitting elements on the intermediate substrate to the third substrate, one by one, may include the step of relatively moving the intermediate substrate and the third substrate each time one by one ... one by one one one by one one one by one one one by one one one by one one one by one one one by one one one by one one one by one one one by one one one by one one one by one one one by one one one by one one one by one one one by one one one by one one one by one one one by one one one by one one one by one one one by one one one by one one one by one one one one by one one one one by one one one one by one one one one by one one one one by one one one one by one one one one by one one one one one by one one one one one by one one one one one one by one one one one one one one one one one one one one

[0012] In some embodiments, the intermediate substrate may include a light-transmitting adhesive layer on its surface.

[0013] In some embodiments, the step of transferring the light emitting elements on the second substrate to the intermediate substrate can be performed without changing the pitch of the light emitting elements.

[0014] In some embodiments, in the step of transferring the light-emitting elements on the second substrate to the intermediate substrate, the light-transmitting adhesive layer may be selected such that the adhesive strength between the light-transmitting adhesive layer and the photosensitive adhesive layer is stronger than the adhesive strength between the light-emitting elements and the transfer adhesive layer.

[0015] In some embodiments, the step of transferring the light-emitting elements on the second substrate to the intermediate substrate may include the steps of bringing the intermediate substrate and the second substrate closer to each other so that the light-transmitting adhesive layer comes into contact with the photosensitive adhesive layer; and the steps of separating the intermediate substrate and the second substrate from each other.

[0016] In some embodiments, the step of transferring the light-emitting elements on the intermediate substrate to the third substrate may include the step of irradiating light to the photosensitive adhesive layer through the intermediate substrate and the light-transmitting adhesive layer.

[0017] By using the transfer method of the present invention, the pitch of light-emitting elements can be changed through a simple process, thereby improving productivity.

[0018] The effects that can be obtained from the exemplary embodiments of the present invention are not limited to the effects mentioned above, and other effects not mentioned can be clearly derived and understood by those skilled in the art to which the exemplary embodiments of the present disclosure pertain from the following description. In other words, unintended effects resulting from practicing the exemplary embodiments of the present disclosure can also be derived by those skilled in the art from the exemplary embodiments of the present disclosure.

[0019] FIG. 1 and FIG. 2 are flowcharts showing a transfer method of a micro light-emitting element according to one embodiment of the present invention.

[0020] FIGS. 3 to 10 are plan views or side views schematically illustrating a transfer method of a micro light-emitting element according to one embodiment of the present invention.

[0021] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. However, the embodiments of the present invention may be modified in various different forms, and the scope of the present invention should not be construed as being limited by the embodiments described below. It is preferable to interpret that the embodiments of the present invention are provided to more completely explain the present invention to those of ordinary skill in the art. Like numbers refer to like elements throughout. Furthermore, various elements and areas in the drawings are schematically drawn. Therefore, the present invention is not limited by the relative sizes or spacings depicted in the accompanying drawings.

[0022] While terms like "first" and "second" may be used to describe various components, these components are not limited by these terms. These terms are used solely to distinguish one component from another. For example, a first component could be referred to as a "second component," and vice versa, without departing from the scope of the present invention.

[0023] The terminology used in this application is only used to describe specific embodiments and is not intended to limit the inventive concept. The singular expression includes the plural expression unless the context clearly indicates otherwise. In this application, it should be understood that the expressions "comprises" or "has" indicate the presence of a feature, number, step, operation, component, part, or combination thereof described in the specification, but do not preclude the possibility of the presence or addition of one or more other features, numbers, operations, components, parts, or combinations thereof.

[0024] Unless otherwise defined, all terms used herein, including technical and scientific terms, have the same meaning as commonly understood by those of ordinary skill in the art to which the present invention pertains. Furthermore, it is to be understood that commonly used terms, such as those defined in dictionaries, should be interpreted to have a meaning consistent with their meaning within the relevant technical context, and should not be interpreted in an overly formal sense unless explicitly defined herein.

[0025] In some embodiments, where implementations are otherwise feasible, specific process sequences may be performed in a different order than described. For example, two processes described in succession may be performed substantially simultaneously, or in a reverse order from the described order.

[0026] In the accompanying drawings, variations in the shapes depicted may be expected, for example, depending on manufacturing techniques and / or tolerances. Therefore, embodiments of the present invention should not be construed as limited to the specific shapes of the regions depicted herein, but should include, for example, variations in shapes resulting from the manufacturing process. The term "and / or" as used herein encompasses each and every combination of the components mentioned.

[0027]

[0028] Figures 1 and 2 are flowcharts illustrating a method for transferring a micro light-emitting element according to one embodiment of the present invention. Figures 3 to 11 are plan views or side views schematically illustrating a method for transferring a micro light-emitting element according to one embodiment of the present invention.

[0029] Referring to FIGS. 1 to 3, a first substrate (10) having a plurality of light-emitting elements (110) attached thereto is provided (S100).

[0030] In some embodiments, the first substrate (10) may be a source substrate. The source substrate may be any one of a sapphire substrate, a glass substrate, a quartz substrate, a silicon (Si) substrate, a gallium arsenide (GaAs) substrate, a gallium phosphide (GaP) substrate, a gallium arsenide phosphide (GaAsP) substrate, a silicon carbide (SiC) substrate, a potassium nitride (GaN) substrate, an aluminum nitride (AlN) substrate, a zinc oxide (ZnO) substrate, and a magnesium oxide (MgO) substrate. Hereinafter, the term "source substrate" may refer to any substrate before the light-emitting elements (110) are transferred to the target substrate that serves as the transfer target.

[0031] In some embodiments, the source substrate may be a semiconductor substrate. The source substrate may be a semiconductor wafer. The light-emitting elements (110) may be, for example, micro LED (light emitting diode) elements. Hereinafter, the light-emitting elements (110) will be described using micro LED elements.

[0032] In some embodiments, the source substrate may be a polymer substrate or a glass substrate, although the present invention is not limited thereto.

[0033] A micro LED element may refer to an LED element having a size of 100 μm x 100 μm or less. The plurality of light-emitting elements (110) which are micro LED elements may be any one of a red micro LED element, a green micro LED element, and a blue micro LED element. A person skilled in the art will understand that the light-emitting wavelength may vary depending on the semiconductor band gap. In some embodiments, the plurality of light-emitting elements (110) may be arranged in a grid shape.

[0034] The blue micro LED element can be manufactured based on GaN. The green micro LED element can be manufactured based on GaN, but by controlling the band gap by varying the composition ratio of the quantum well structure material (InGaN) in the light-emitting region compared to the blue micro LED element. The red micro LED element can be manufactured based on GaAs.

[0035] Referring to FIGS. 1 and 4, the second substrate (20) can be placed so as to face the light-emitting elements (110) on the first substrate (10).

[0036] The light-emitting elements (110) may be arranged on the first substrate (10) by a photosensitive adhesive layer (115). The light-emitting elements (110) may be arranged in a grid pattern in a first direction (e.g., x-axis direction) and a second direction (e.g., y-axis direction) as illustrated in FIG. 3.

[0037] In some embodiments, the photosensitive adhesive layer (115) may include an adhesion promoter resin, such as a polyimide-based resin, a photoresist (PR), or a resin such as SU-8. In some embodiments, the photosensitive adhesive layer (115) may include a photodegradable polymer resin. In particular, the photosensitive adhesive layer (115) may include a photodegradable polymer resin that can be photodegraded in response to irradiation with laser light. However, the photosensitive adhesive layer (115) is not limited to these, and any material that can locally reduce the bonding strength by any controllable means, such as light, heat, electromagnetic waves, etc., is sufficient.

[0038] The second substrate (20) may be any one of a sapphire substrate, a glass substrate, a quartz substrate, a silicon (Si) substrate, a gallium arsenide (GaAs) substrate, a gallium phosphide (GaP) substrate, a gallium arsenide phosphide (GaAsP) substrate, a silicon carbide (SiC) substrate, a potassium nitride (GaN) substrate, an aluminum nitride (AlN) substrate, a zinc oxide (ZnO) substrate, and a magnesium oxide (MgO) substrate. However, the present invention is not limited thereto.

[0039] The second substrate (20) may include a transfer adhesive layer (155) on its surface. Any adhesive capable of attaching the light emitting elements (110) with an appropriate strength may be employed for the transfer adhesive layer (155). For example, the transfer adhesive layer (155) may include an epoxy-based adhesive, a silicone-based adhesive, or a urethane-based adhesive. In some embodiments, the transfer adhesive layer (155) may use, but is not limited to, a polydimethyl siloxane-based adhesive or adhesive or curable composition, a polymethylvinyl siloxane-based adhesive or adhesive or curable composition, or an alkoxy silicone-based adhesive or adhesive or curable composition.

[0040] In FIG. 4, the size of the second substrate (20) is shown to be the same as that of the first substrate (10), but the present invention is not limited thereto. In some embodiments, the size of the second substrate (20) may be larger than that of the first substrate (10).

[0041] The light emitting elements (110) may be arranged on the first substrate (10) with a first pitch (P1) in a second direction (e.g., in the y-axis direction). In some embodiments, the light emitting elements (110) may be arranged on the first substrate (10) with a third pitch (P3) (see FIG. 5A and FIG. 9) in a first direction (e.g., in the x-axis direction). In some embodiments, the third pitch (P3) may be substantially the same as the first pitch (P1). In some other embodiments, the third pitch (P3) may be different from the first pitch (P1).

[0042] Referring to FIG. 1, FIG. 5, and FIG. 5a, a plurality of light-emitting elements (110) on a first substrate (10) can be transferred one line at a time to the second substrate (20) (S200).

[0043] In some embodiments, the light emitting elements (110) on the first substrate (10) can be transferred by irradiating light onto the photosensitive adhesive layer (115).

[0044] Specifically, among the light emitting elements (110) on the first substrate (10), a line of light emitting elements (110) to be transferred can be aligned with a target position on the second substrate (20). Thereafter, light can be irradiated to the photosensitive adhesive layer (115) through the first substrate (10). The light irradiated to the photosensitive adhesive layer (115) can reduce or eliminate the adhesive strength of the photosensitive adhesive layer (115). In some embodiments, the adhesive strength of the photosensitive adhesive layer (115) can be reduced or eliminated by photolysis by the irradiated light. In some embodiments, the photosensitive adhesive layer (115) can be partially photodegraded by the irradiated light.

[0045] In some embodiments, the photodegradation may be achieved by irradiating the photosensitive adhesive layer (115) with light having energy of a predetermined wavelength. In some embodiments, the photodegradation may be achieved by irradiating the photosensitive adhesive layer (115) with a laser beam that passes through the first substrate (10).

[0046] In some embodiments, the photolysis may be performed while the light-emitting elements (110) are spaced apart from the second substrate (20). In some other embodiments, the photolysis may be performed while the light-emitting elements (110) are in contact with the second substrate (20).

[0047] In order to transfer a row of light-emitting elements (110) to a target position on the second substrate (20), a laser beam may be irradiated onto the row of light-emitting elements (110) while traveling in one direction. For example, the laser beam may be irradiated onto the row of light-emitting elements (110) while traveling in a first direction (e.g., the x-axis direction of FIG. 3). Accordingly, the leftmost row of light-emitting elements (110) among the light-emitting elements (110) illustrated in FIG. 3 may be transferred to the leftmost row of the light-emitting elements (110) illustrated in FIG. 5A.

[0048] By the above transfer, the light emitting elements (110) of the single line can be attached to the transfer adhesive layer (155) on the second substrate (20). In some embodiments, the light emitting elements (110) can be detached from the first substrate (10) and dropped and attached to the transfer adhesive layer (155) by irradiating the laser light. In some embodiments, the light emitting elements (110) can be detached from the first substrate (10) and transferred onto the second substrate (20) by forming a stronger adhesive force by contacting the transfer adhesive layer (155) and lowering the adhesive force of the photosensitive adhesive layer (115) by irradiating the laser light. However, other light emitting elements (110) that are not irradiated with the laser light may remain on the first substrate (10).

[0049] As described above, after one line of light-emitting elements (110) is transferred to a target position on the second substrate (20), the next line of light-emitting elements (110) can be transferred to a target position on the second substrate (20).

[0050] The light emitting elements (110) on the second substrate (20) may have a second pitch (P2) in the second direction (e.g., y-axis direction). That is, a previously transferred row of light emitting elements (110) and a subsequently transferred row of light emitting elements (110) have the second pitch (P2). In some embodiments, the second pitch (P2) may be greater than the first pitch (P1). In some embodiments, the second pitch (P2) may not be an integer multiple of the first pitch (P1). For example, the second pitch (P2) may have a magnification that is not an integer multiple, such as 1.3 times, 1.4 times, 1.5 times, 1.6 times, 1.7 times, 1.8 times, 1.9 times, 2.1 times, 2.2 times, 2.3 times, or 2.4 times the first pitch (P1).

[0051] In order to transfer the next row of light-emitting elements (110) to a target position on the second substrate (20), the first substrate (10) and the second substrate (20) can be moved relatively to each other. In some embodiments, the first substrate (10) is fixed, and the second substrate (20) moves in a second direction (e.g., in the y-axis direction), thereby aligning the next row of light-emitting elements (110) to a target position on the second substrate (20).

[0052] In some other embodiments, the next row of light-emitting elements (110) can be aligned to a target position on the second substrate (20) by moving the first substrate (10) in a second direction (e.g., in the y-axis direction) while the second substrate (20) is fixed. In some embodiments, the next row of light-emitting elements (110) can be aligned to a target position on the second substrate (20) by relatively moving the first substrate (10) and the second substrate (20) in a second direction (e.g., in the y-axis direction).

[0053] Thereafter, the next row of light-emitting elements (110) can be transferred to the second substrate (20) in the same manner as described above. That is, in order to transfer the next row of light-emitting elements (110) to a target position on the second substrate (20), a laser beam can be irradiated to the next row of light-emitting elements (110) while traveling in one direction. For example, the laser beam can be irradiated to the next row of light-emitting elements (110) while traveling in the first direction (e.g., the x-axis direction of FIG. 3). Accordingly, the light-emitting elements (110) in the second row from the left among the light-emitting elements (110) illustrated in FIG. 3 can be transferred to the second row from the left among the light-emitting elements (110) illustrated in FIG. 5a.

[0054] The spacing of the light emitting elements (110) of FIG. 5A in the second direction (e.g., in the y-axis direction) may be greater than the spacing of the light emitting elements (110) of FIG. 3 in the second direction (e.g., in the y-axis direction). However, contrary to what is illustrated in FIG. 5A, the spacing of the light emitting elements (110) transferred onto the second substrate (20) in the second direction (e.g., in the y-axis direction) may be smaller than the spacing of the light emitting elements (110) of FIG. 3 in the second direction (e.g., in the y-axis direction).

[0055] As described above, after the light emitting elements (110) of the second row are transferred to the target position on the second substrate (20), the light emitting elements (110) of the next row (i.e., the third row) can be transferred to the target position on the second substrate (20).

[0056] By repeating the above process, the light emitting elements (110) on the second substrate (20) can be arranged with a second pitch (P2) in the second direction (e.g., y-axis direction). At this time, the light emitting elements (110) on the second substrate (20) can maintain the original third pitch (P3) in the first direction (e.g., x-axis direction).

[0057]

[0058] Thereafter, the light emitting elements (110) on the second substrate (20) can be transferred to the third substrate (S300). Specifically, in order to transfer the light emitting elements (110) on the second substrate (20) to the third substrate, the light emitting elements (110) on the second substrate (20) can be transferred to the intermediate substrate (90) (S310), and then the light emitting elements (110) on the intermediate substrate (90) can be transferred to the third substrate (30) (S320).

[0059] Referring to FIG. 2 and FIG. 6, in order to transfer the light emitting elements (110) on the second substrate (20) to the intermediate substrate (90), the intermediate substrate (90) is placed on the second substrate (20).

[0060] The above intermediate substrate (90) may be any one of a sapphire substrate, a glass substrate, a quartz substrate, a silicon (Si) substrate, a gallium arsenide (GaAs) substrate, a gallium phosphide (GaP) substrate, a gallium arsenide phosphide (GaAsP) substrate, a silicon carbide (SiC) substrate, a potassium nitride (GaN) substrate, an aluminum nitride (AlN) substrate, a zinc oxide (ZnO) substrate, and a magnesium oxide (MgO) substrate. However, the present invention is not limited thereto.

[0061] The intermediate substrate (90) may include a light-transmitting adhesive layer (157) on a surface facing the second substrate (20). Any adhesive that can transmit light and attach the light-emitting elements (110) with an appropriate strength may be used for the light-transmitting adhesive layer (157). For example, the light-transmitting adhesive layer (157) may include an epoxy-based adhesive, a silicone-based adhesive, or a urethane-based adhesive. In some embodiments, the light-transmitting adhesive layer (157) may use, but is not limited to, a polydimethyl siloxane-based adhesive or adhesive or curable composition, a polymethylvinyl siloxane-based adhesive or adhesive or curable composition, or an alkoxy silicone-based adhesive or adhesive or curable composition.

[0062] In Fig. 6, the size of the intermediate substrate (90) and the size of the second substrate (20) are shown to be the same, but the present invention is not limited thereto. The intermediate substrate (90) is not particularly limited as long as it has a size that can attach the entire light-emitting element (110) on the second substrate (20).

[0063] Referring to FIGS. 2 and 7, in order to transfer the light-emitting elements (110) on the second substrate (20) to the intermediate substrate (90), the intermediate substrate (90) and the second substrate (20) can be brought into close proximity to each other. The intermediate substrate (90) and the second substrate (20) can be brought into close proximity to each other until the light-transmitting adhesive layer (157) of the intermediate substrate (90) comes into contact with the photosensitive adhesive layer (115) of the light-emitting element (110).

[0064] In some embodiments, the intermediate substrate (90) can be brought toward the second substrate (20) while the second substrate (20) is stationary. In some other embodiments, the second substrate (20) can be brought toward the intermediate substrate (90) while the intermediate substrate (90) is stationary. In some embodiments, the intermediate substrate (90) and the second substrate (20) can be brought toward each other by moving each other toward each other.

[0065] When the light-transmitting adhesive layer (157) of the intermediate substrate (90) comes into contact with the light-sensitive adhesive layer (115) of the light-emitting element (110), adhesive force is formed between the light-transmitting adhesive layer (157) and the light-sensitive adhesive layer (115). The adhesive strength between the light-transmitting adhesive layer (157) and the light-sensitive adhesive layer (115) may be stronger than the adhesive strength between the light-emitting element (110) and the transfer adhesive layer (155). The light-transmitting adhesive layer (157) may be selected such that the adhesive strength between the light-transmitting adhesive layer (157) and the photosensitive adhesive layer (115) is stronger than the adhesive strength between the light-emitting element (110) and the transfer adhesive layer (155).

[0066] In some embodiments, the light-transmitting adhesive layer (157) may comprise substantially the same material as the transfer adhesive layer (155). In some embodiments, the light-transmitting adhesive layer (157) may be composed of substantially the same material as the transfer adhesive layer (155).

[0067] Even if the above-described light-transmitting adhesive layer (157) is composed of substantially the same material as the above-described transfer adhesive layer (155), the adhesive strength between the above-described light-transmitting adhesive layer (157) and the above-described photosensitive adhesive layer (115) may be different from the adhesive strength between the above-described light-emitting element (110) and the above-described transfer adhesive layer (155). This is because the contact surfaces of the above-described light-transmitting adhesive layer (157) (i.e., the material of the transfer adhesive layer (155)) and the above-described light-emitting element (110) are made of different materials.

[0068] Referring to FIG. 2 and FIG. 8, the intermediate substrate (90) can be separated from the second substrate (20).

[0069] As described above, the light-transmitting adhesive layer (157) is selected such that the adhesive strength between the light-transmitting adhesive layer (157) and the photosensitive adhesive layer (115) is stronger than the adhesive strength between the light-emitting element (110) and the transfer adhesive layer (155). Therefore, the adhesive strength between the light-transmitting adhesive layer (157) and the photosensitive adhesive layer (115) overcomes the adhesive strength between the light-emitting element (110) and the transfer adhesive layer (155).

[0070] When the intermediate substrate (90) is separated from the second substrate (20), the light emitting element (110) is detached from the transfer adhesive layer (155), and adhesion between the light-transmitting adhesive layer (157) and the photosensitive adhesive layer (115) can be maintained.

[0071] Since the light-emitting elements (110) are transferred to the intermediate substrate (90) by adhesion between the light-transmitting adhesive layer (157) and the photosensitive adhesive layer (115), the pitch of the light-emitting elements (110) in the first direction (e.g., x-axis direction) and the second direction (e.g., y-axis direction) may not substantially change at this stage.

[0072] Referring to FIG. 2 and FIG. 9, the third substrate (30) can be placed so as to face the light emitting elements (110) on the intermediate substrate (90).

[0073] The third substrate (30) may be any one of a sapphire substrate, a glass substrate, a quartz substrate, a silicon (Si) substrate, a gallium arsenide (GaAs) substrate, a gallium phosphide (GaP) substrate, a gallium arsenide phosphide (GaAsP) substrate, a silicon carbide (SiC) substrate, a potassium nitride (GaN) substrate, an aluminum nitride (AlN) substrate, a zinc oxide (ZnO) substrate, and a magnesium oxide (MgO) substrate. However, the present invention is not limited thereto.

[0074] The third substrate (30) may include an adhesive layer (159) on its surface. Any adhesive capable of attaching the light emitting elements (110) with an appropriate strength may be employed for the adhesive layer (159). For example, the adhesive layer (159) may include an epoxy-based adhesive, a silicone-based adhesive, or a urethane-based adhesive. In some embodiments, the adhesive layer (159) may use, but is not limited to, a polydimethyl siloxane-based adhesive or adhesive or curable composition, a polymethylvinyl siloxane-based adhesive or adhesive or curable composition, or an alkoxy silicone-based adhesive or adhesive or curable composition.

[0075] In Fig. 9, the size of the intermediate substrate (90) and the size of the third substrate (30) are shown to be the same, but the present invention is not limited thereto. In some embodiments, the size of the third substrate (30) may be larger than that of the intermediate substrate (90).

[0076] It should be noted that in FIG. 9, the intermediate substrate (90) is depicted as viewed in a different direction from that in FIG. 8. That is, FIG. 8 shows a view of the intermediate substrate (90) viewed in a first direction (e.g., x-axis direction) (see FIG. 5a). On the other hand, FIG. 9 shows a view of the intermediate substrate (90) viewed in a second direction (e.g., y-axis direction) (see FIG. 5a).

[0077] The light emitting elements (110) may be arranged on the intermediate substrate (90) in a second direction (e.g., in the y-axis direction) with a second pitch (P2) (see FIG. 5). In some embodiments, the light emitting elements (110) may be arranged on the intermediate substrate (90) in a first direction (e.g., in the x-axis direction) with a third pitch (P3). In some embodiments, the third pitch (P3) may be substantially the same as the first pitch (P1). In some other embodiments, the third pitch (P3) may be different from the first pitch (P1).

[0078] Referring to FIGS. 9 and 10, a plurality of light-emitting elements (110) on an intermediate substrate (90) can be transferred one line at a time to the third substrate (30) (S320).

[0079] In some embodiments, the light emitting elements (110) on the intermediate substrate (90) can be transferred by irradiating light onto the photosensitive adhesive layer (115).

[0080] Specifically, among the light emitting elements (110) on the intermediate substrate (90), a line of light emitting elements (110) to be transferred can be aligned with a target position on the third substrate (30). Thereafter, light can be irradiated to the photosensitive adhesive layer (115) through the intermediate substrate (90) and the light-transmitting adhesive layer (157). The light irradiated to the photosensitive adhesive layer (115) can reduce or eliminate the adhesive strength of the photosensitive adhesive layer (115). In some embodiments, the adhesive strength of the photosensitive adhesive layer (115) can be reduced or eliminated by photolysis by the irradiated light. In some embodiments, the photosensitive adhesive layer (115) can be partially photodegraded by the irradiated light.

[0081] In some embodiments, the photodegradation may be achieved by irradiating the photosensitive adhesive layer (115) with light having energy of a predetermined wavelength. In some embodiments, the photodegradation may be achieved by irradiating the photosensitive adhesive layer (115) with a laser beam that passes through the intermediate substrate (90) and the light-transmitting adhesive layer (157).

[0082] In some embodiments, the photolysis may be performed while the light-emitting elements (110) are spaced apart from the third substrate (30). In some other embodiments, the photolysis may be performed while the light-emitting elements (110) are in contact with the third substrate (30).

[0083] In order to transfer a row of light-emitting elements (110) to a target position on the third substrate (30), a laser beam may be irradiated onto the row of light-emitting elements (110) while traveling in one direction. For example, the laser beam may be irradiated onto the row of light-emitting elements (110) while traveling in a second direction (e.g., the y-axis direction of FIG. 9). Accordingly, the leftmost row of light-emitting elements (110) among the light-emitting elements (110) illustrated in FIG. 9 may be transferred to the leftmost row of the light-emitting elements (110) illustrated in FIG. 10.

[0084] By the above transfer, the light emitting elements (110) of the single line can be attached to the adhesive layer (159) on the third substrate (30). In some embodiments, the light emitting elements (110) can be detached from the intermediate substrate (90) and dropped and attached to the adhesive layer (159) by irradiating the laser light. In some embodiments, the light emitting elements (110) can be detached to the intermediate substrate (90) and transferred onto the third substrate (30) by forming a stronger adhesive force by contacting the adhesive layer (159) and having the adhesive strength of the photosensitive adhesive layer (115) reduced by irradiating the laser light. However, other light emitting elements (110) that are not irradiated with the laser light can remain on the intermediate substrate (90).

[0085] As described above, after one line of light-emitting elements (110) is transferred to a target position on the third substrate (30), the next line of light-emitting elements (110) can be transferred to a target position on the third substrate (30).

[0086] The light emitting elements (110) on the third substrate (30) may have a fourth pitch (P4) in the first direction (e.g., x-axis direction). That is, a previously transferred row of light emitting elements (110) and a subsequently transferred row of light emitting elements (110) have the fourth pitch (P4). In some embodiments, the fourth pitch (P4) may be greater than the third pitch (P3). In some embodiments, the fourth pitch (P4) may not be an integer multiple of the third pitch (P3). For example, the fourth pitch (P4) may have a magnification that is not an integer multiple, such as 1.3 times, 1.4 times, 1.5 times, 1.6 times, 1.7 times, 1.8 times, 1.9 times, 2.1 times, 2.2 times, 2.3 times, or 2.4 times the third pitch (P3).

[0087] In order to transfer the next row of light-emitting elements (110) to a target position on the third substrate (30), the intermediate substrate (90) and the third substrate (30) can be moved relatively to each other. In some embodiments, the third substrate (30) can be moved in a first direction (e.g., x-axis direction) while the intermediate substrate (90) is fixed, thereby aligning the next row of light-emitting elements (110) to a target position on the third substrate (30).

[0088] In some other embodiments, the next row of light-emitting elements (110) can be aligned to a target position on the third substrate (30) by moving the intermediate substrate (90) in a first direction (e.g., in the x-axis direction) while the third substrate (30) is fixed. In some embodiments, the next row of light-emitting elements (110) can be aligned to a target position on the third substrate (30) by relatively moving the intermediate substrate (90) and the third substrate (30) in a first direction (e.g., in the x-axis direction).

[0089] Thereafter, the next row of light-emitting elements (110) can be transferred to the third substrate (30) in the same manner as described above. That is, in order to transfer the next row of light-emitting elements (110) to a target position on the third substrate (30), a laser beam can be irradiated to the next row of light-emitting elements (110) while traveling in one direction. For example, the laser beam can be irradiated to the next row of light-emitting elements (110) while traveling in a second direction (e.g., the y-axis direction of FIG. 9). Accordingly, the light-emitting elements (110) in the second row from the left among the light-emitting elements (110) illustrated in FIG. 9 can be transferred to the second row from the left among the light-emitting elements (110) illustrated in FIG. 10.

[0090] The spacing of the light emitting elements (110) of FIG. 10 in the first direction (e.g., x-axis direction) may be greater than the spacing of the light emitting elements (110) of FIG. 9 in the first direction (e.g., x-axis direction). However, contrary to what is illustrated in FIG. 10, the spacing of the light emitting elements (110) transferred onto the third substrate (30) in the first direction (e.g., x-axis direction) may be smaller than the spacing of the light emitting elements (110) of FIG. 9 in the first direction (e.g., x-axis direction).

[0091] As described above, after the light emitting elements (110) of the second row are transferred to the target position on the third substrate (30), the light emitting elements (110) of the next row (i.e., the third row) can be transferred to the target position on the third substrate (30).

[0092] By repeating the above process, the light emitting elements (110) on the third substrate (30) can be arranged with a fourth pitch (P4) in the first direction (e.g., x-axis direction). At this time, the light emitting elements (110) on the third substrate (30) can maintain the original second pitch (P2) (see FIG. 5) in the second direction (e.g., y-axis direction).

[0093] In some embodiments, the photosensitive adhesive layer (115) can be removed to expose the electrodes (112a, 112b) of each light-emitting element (110).

[0094] In some embodiments, the photosensitive adhesive layer (115) may be removed by wet etching or dry etching. However, the present invention is not limited thereto.

[0095] While the embodiments of the present invention have been described in detail above, those skilled in the art will appreciate that various modifications and variations can be made to the present invention without departing from the spirit and scope of the invention as defined in the appended claims. Therefore, modifications to future embodiments of the present invention will not depart from the scope of the invention.

[0096]

[0097] [Explanation of symbols]

[0098] 10: First substrate

[0099] 20: Second substrate

[0100] 30: Third substrate

[0101] 90: Intermediate substrate

[0102] 110: Light-emitting element

[0103] 115: Photosensitive adhesive layer

[0104] 155: Transfer adhesive layer

[0105] 157: Translucent adhesive layer

[0106] 159: Adhesive layer

Claims

1. A step of providing a first substrate having light-emitting elements arranged in a grid pattern attached thereto; A step of transferring light-emitting elements on the first substrate one by one to the second substrate, wherein the first substrate and the second substrate are moved relatively each time the light-emitting elements extending in the first direction are transferred to adjust the interval between the light-emitting elements extending in the first direction in the second direction; and A step of transferring light emitting elements on the second substrate to a third substrate, wherein the step of transferring the light emitting elements in a row extending in the second direction to the third substrate adjusts the spacing between the light emitting elements in the first direction; A method for transferring a micro luminescent element comprising:

2. In paragraph 1, A method for transferring micro-luminescent elements, characterized in that the light-emitting elements are attached to the first substrate through a photosensitive adhesive layer.

3. In paragraph 1, A method for transferring micro-light emitting elements, characterized in that in the step of transferring light emitting elements on the first substrate one by one to the second substrate, the light emitting elements on the first substrate are transferred to the second substrate by photodecomposition of the photosensitive adhesive layer.

4. In paragraph 3, The second substrate comprises a transfer adhesive layer, A method for transferring micro light-emitting elements, characterized in that in the step of transferring light-emitting elements on the first substrate one line at a time to the second substrate, the light-emitting elements on the first substrate are transferred onto the transfer adhesive layer of the second substrate.

5. In paragraph 1, The light emitting elements are arranged at a first pitch in a second direction on the first substrate, and at a second pitch in a second direction on the second substrate. A method for transferring a micro-luminescent element, characterized in that the second pitch is larger than the first pitch.

6. In paragraph 5, A method for transferring a micro-luminescent element, characterized in that the second pitch is not an integer multiple of the first pitch.

7. In paragraph 1, The step of transferring the light-emitting elements on the second substrate to the third substrate is: A step of transferring the light-emitting elements on the second substrate to an intermediate substrate; and A step of transferring light-emitting elements on the intermediate substrate to the third substrate; Including, A method for transferring micro light-emitting elements, characterized in that the step of transferring the light-emitting elements on the intermediate substrate one by one to the third substrate includes the step of relatively moving the intermediate substrate and the third substrate each time the light-emitting elements extending in the second direction are transferred in order to adjust the spacing between the light-emitting elements extending in the second direction in the first direction.

8. In paragraph 7, A method for transferring a micro-luminescent element, characterized in that the intermediate substrate includes a light-transmitting adhesive layer on its surface.

9. In paragraph 8, A method for transferring micro light-emitting elements, characterized in that the step of transferring light-emitting elements on the second substrate to the intermediate substrate is performed without changing the pitch of the light-emitting elements.

10. In paragraph 8, In the step of transferring the light-emitting elements on the second substrate to the intermediate substrate, A method for transferring a micro light-emitting element, characterized in that the light-transmitting adhesive layer is selected such that the adhesive strength between the light-transmitting adhesive layer and the photosensitive adhesive layer is stronger than the adhesive strength between the light-emitting element and the transfer adhesive layer.

11. In Article 10, The step of transferring the light-emitting elements on the second substrate to the intermediate substrate is: A step of bringing the intermediate substrate and the second substrate close to each other to bring the light-transmitting adhesive layer into contact with the light-sensitive adhesive layer; and A step of separating the intermediate substrate and the second substrate from each other; A method for transferring a micro-luminescent element, characterized by including a.

12. In paragraph 10, A method for transferring micro-light emitting elements, characterized in that the step of transferring light emitting elements on the intermediate substrate to the third substrate includes the step of irradiating light to the photosensitive adhesive layer through the intermediate substrate and the light-transmitting adhesive layer.

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