Transfer apparatus using light, and transfer method using same

Abstract

The present invention relates to a transfer apparatus using light, and a transfer method using same, the apparatus having a recessed stamp during pick-up so as to perform perfect pick-up, and changing the shape of the stamp from a recessed shape to a flat or protruding shape so that perfect release can be performed. According to the present invention, a chip-type electronic component can be transferred without damage, and a large amount of electronic components can be rapidly transferred. In addition, selective transfer and also repair of electronic components, according to a specific pattern, are possible.

Description

Light-based transcription device and transcription method using the same

[0001] The present invention relates to a transfer device using light-based shape transformation capable of selectively transferring an ultra-small target, and a transfer method using the same.

[0002] In general, LED devices based on inorganic semiconductors offer superior performance and stability compared to conventional organic light-emitting displays such as OLED, resulting in higher display quality. Technologies for constructing displays using micro LEDs are being developed as a next-generation display technology.

[0003] The method of constructing these Micro LED displays is to manufacture red, green, and blue LEDs respectively on a wafer using the LED Epitaxy growth method, and then cut the manufactured LEDs into small mini or micro-sized chips to fit the pixel size of the display.

[0004] Afterwards, the cut LED chips are assembled into chips of each color (RED, Green, Blue) and moved to the display substrate to align them to the color pixels in three steps to form the display pixels.

[0005] However, since the pixels that make up the display are in the tens of billions, picking them up and placing them one by one requires a very long process time and is very expensive.

[0006] In order to overcome the limitations of the aforementioned micro LED transfer technology, a soft stamp method utilizing the imperfect point-adhesive properties of a simple flat, flexible elastic stamp or a transfer technology utilizing strong electrostatic bonding force using static electricity for complete pickup has been developed.

[0007] However, in the case of the soft stamp method, there is no direct exposure to electricity and static electricity, so there is no damage during the transfer process of the micro LED, but there is a problem that the micro LED cannot be picked up and placed without missing due to the control of the imperfect point adhesion characteristics. In contrast, in the case of the electrostatic transfer method, a strong electrostatic bonding force can be obtained, so the micro LED can be picked up and placed without missing. However, there are problems such as damage to the micro LED during the strong electric-induced static electricity generation process, making it difficult to commercialize the ocean transfer technology of the micro LED.

[0008] These issues apply equally to mass transfer of small targets such as micro LEDs, semiconductors, and even chip-shaped electronic components.

[0009] The purpose of the present invention is to provide a transfer device and a transfer method using the same, which are capable of mass transferring chip-shaped electronic components that can solve conventional problems, and which enable complete pickup of a stamp using photodeformation by light without using an electrostatic method by electricity, and which enable reliable pickup of chip-shaped electronic components through shape deformation and reversible photodeformation by light, and which enable placing of the picked-up chip-shaped electronic components at a desired location.

[0010] As a means of solving the above problem, according to the present disclosure, a transfer device can be provided that forms a concave stamp in the shape of a suction cup by photomorphism by light of a specific wavelength when picking up to enable perfect pick up, and that changes the shape of the stamp from a concave shape to a flat or convex shape through photomorphism by light irradiation of another specific wavelength when releasing a chip-shaped electronic component for placement after transfer to enable perfect release.

[0011] In the present disclosure, the stamp can be configured to reversibly change between a concave sucker shape and a convex shape, or between a concave sucker shape and a flat shape, by different photomorphic deformation characteristics caused by light of specific different wavelengths.

[0012] Meanwhile, the stamp may include an Azo Polymer that can change the arrangement of Cis-Trans molecules by triggering light to change its shape.

[0013] Additionally, Azo Polymer may or may not have liquid crystal properties, and the shape of the stamp may change due to physical changes in the molecular arrangement of the liquid crystal Azo Polymer caused by light.

[0014] Meanwhile, by selectively irradiating the stamp with light of the first wavelength or light of the second wavelength, a target, for example, an electronic component in the form of a chip, can be perfectly picked up and released.

[0015] Meanwhile, the first light and the second light may be ultraviolet light, visible light or infrared light, and their wavelengths may be selected differently within the range of 100 nm to 2000 nm.

[0016] Meanwhile, the stamp can be patterned small enough to fit the pixel size of the display and configured into multiple arrays so that multiple chip-shaped electronic components can be transferred and moved simultaneously.

[0017] Additionally, a transfer method may be provided that can pick and transfer a single color micro LED of red, green, or blue from a wafer.

[0018] Additionally, a concave suction-type stamp can be formed by irradiating light of the first wavelength of light to a desired pixel location. A micro-stamp formed in this manner can pick up a micro LED at a desired location without missing anything by utilizing the physical adhesive force of the suction-type stamp.

[0019] In addition, a transfer method can be provided that can sequentially pick up Red, Green, and Blue micro LEDs in any order, and then actuate all positions of the stamp into a convex or flat shape by light of a second light having a different wavelength, thereby photodeforming the shape of the suction cup photodeformed by the first wavelength, thereby removing the strong adhesive force of the micro suction cup, thereby simultaneously placing the micro LEDs.

[0020] Additionally, this process can be used in a continuous roll process where stamps are placed on the outer surface of a drum (or roller).

[0021] The transfer device utilizing photodeformation by light according to the present invention and the transfer method using the same enable transfer without electrical and magnetic damage to electronic components in the form of chips, and can rapidly transfer a large number of micro LEDs through pick-up and transfer without omission by controlling the physical adhesive properties of a micro stamp with photoreversible deformation. In addition, it has the effect of enabling selective transfer according to a specific pattern and repair of a single micro LED.

[0022] FIG. 1 is a cross-sectional view of a light-based transfer device according to a first embodiment of the present disclosure.

[0023] Figure 2 is an enlarged cross-sectional view centered on the stamp in the first embodiment.

[0024] Figure 3a is a conceptual diagram of a light-driven material in the present disclosure.

[0025] FIG. 3b and FIG. 3c are conceptual diagrams illustrating a modified example in which the stamp in the present disclosure includes a light-absorbing expansion layer.

[0026] FIG. 4a and FIG. 4b are diagrams showing the operational status of the stamp in the present disclosure.

[0027] FIG. 5 is a cross-sectional view of a light-using transfer device according to a second embodiment of the present disclosure.

[0028] Figures 6a and 6b are operating state diagrams of the second embodiment.

[0029] Fig. 7 is a cross-sectional view of a light-using transfer device according to a third embodiment of the present disclosure.

[0030] Figure 8 is an operating state diagram of the third embodiment of the present disclosure.

[0031] Figures 9a and 9b are usage diagrams of the third embodiment.

[0032] Fig. 10 is a flowchart of a light-using transfer method according to the fourth embodiment of the present disclosure.

[0033] Figures 11a and 11b are conceptual diagrams illustrating the concept of transferring a target according to the fourth embodiment.

[0034] Figure 12 is a flowchart showing the pickup steps in detail in the fourth embodiment.

[0035] Figure 13 is a conceptual diagram illustrating a process of picking up according to the order of Figure 12.

[0036] Figure 14 is a flowchart detailing another pickup step in the fourth embodiment.

[0037] Figure 15 is a conceptual diagram illustrating a process of picking up according to the order of Figure 14.

[0038] Fig. 16 is a flowchart of a light-using transfer method according to the fifth embodiment of the present disclosure.

[0039] Figures 17a, 17b and 17c are conceptual diagrams illustrating a process of transcribing a target according to the fifth embodiment of the present disclosure.

[0040] Fig. 18 is a flowchart of a light-using transfer method according to the sixth embodiment of the present disclosure.

[0041] Figures 19a, 19b, 19c and 19d are conceptual diagrams illustrating the picking process according to the order of Figure 18.

[0042] Figure 20 is a flowchart of a light-using transfer method according to the seventh embodiment of the present disclosure.

[0043] Figure 21 is a conceptual diagram illustrating a step of picking up a target in the seventh embodiment.

[0044] Hereinafter, a light-based transfer device and a transfer method using the same according to embodiments of the present invention will be described in detail with reference to the attached drawings. In the following description of the embodiments, the names of each component may be referred to by different names in the art. However, if they have functional similarity and identity, they can be viewed as equivalent configurations even if modified embodiments are adopted. In addition, the symbols added to each component are described for the convenience of explanation. However, the content depicted in the drawings in which these symbols are described does not limit each component to the scope within the drawings. Similarly, even if an embodiment with some modifications to the configurations in the drawings is adopted, they can be viewed as equivalent configurations if they have functional similarity and identity. In addition, if it is recognized as a component that should be included naturally in light of the general level of a technician in the relevant technical field, a description thereof will be omitted.

[0045] In the present disclosure, the light for transformation can be any type of light source applicable to semiconductor and display manufacturing devices. As an example, an exposure device used in conventional display manufacturing can be utilized in the present disclosure.

[0046] In addition, the term "target" in the present disclosure may be an electronic component that is a target of transcription, ranging from several hundred millimeters (mm) in size, from several thousand micrometers (μm) in size, or from several hundred nanometers (nm) in size. In addition, the electronic component in chip form may be a semiconductor before / after packaging, or, for example, a micro LED.

[0047] Hereinafter, a light-using transfer device (1) according to the present disclosure will be described with reference to FIGS. 1 to 9b.

[0048] Fig. 1 is a cross-sectional view of a light-using transfer device (1) according to the first embodiment of the present disclosure, and Fig. 2 is an enlarged cross-sectional view centered on a stamp (20) in the first embodiment.

[0049] Referring to FIGS. 1 and 2, a light-using transfer device (1) according to the first embodiment of the present disclosure is configured to pick up at least one target (100) and place it at a desired location.

[0050] The first embodiment of the present disclosure, a transfer device (1), may be configured to include a transparent substrate (10), a stamp (20), and a fixing member (30).

[0051] A transparent substrate (10) serves as a base for fixing at least one stamp (20). The transparent substrate (10) may be applied in various sizes depending on the transfer process. The transparent substrate (10) may be configured to allow light of a specific wavelength to pass through.

[0052] Although not shown, the transparent substrate (10) is coupled with a separate horizontal driving element so that its horizontal position can be precisely adjusted during the transfer process. In addition, the transparent substrate (10) is coupled with a vertical driving element so that its vertical position can also be precisely adjusted.

[0053] Meanwhile, although not shown, a light source for irradiating light used in the present disclosure may be provided on the upper side of the transparent substrate (10). At least one light source may irradiate light having a wavelength required for the process toward the transparent substrate (10).

[0054] The stamp (20) is configured to directly pick up or place a target (100). The stamp (20) can reversibly change between a first form and a second form. The stamp (20) may be provided on one surface of a transparent substrate (10). As an example, the stamp (20) may be provided in a direction toward a work space on a transparent substrate (10) configured in a flat shape. The work space refers to a space where a target (100) is picked up or placed.

[0055] The center of the stamp (20) may be provided with a fixing portion (30) for connection to a transparent substrate (10). In the present disclosure, the fixing portion (30) is shown as thick, but this is exaggerated for the purpose of explanation, and the fixing portion (30) may be formed as a thin layer as an adhesive, or may be mechanically configured to have a predetermined volume.

[0056] The stamp (20) can be changed into a first shape by a first light having a first wavelength (λ1). It can also be changed into a second shape by a second light having a second wavelength (λ2).

[0057] The stamp (20) has a concave shape when in its first form and can be transformed into the shape of a widely known suction cup. In addition, the stamp (20) can be transformed into a flat shape when in its second form.

[0058] In the present disclosure, the stamp may include a photo-actuated material. Photo-actuation means that light is irradiated on the stamp, and mechanical (or physical) deformation occurs. The photo-actuation may be photo-chemical conversion actuation, photo-thermal conversion actuation, or photo-electric conversion actuation.

[0059] In one embodiment, the stamp can be comprised of at least one of carbon nanoparticles, metal nanoparticles, semiconductor nanostructures, transition metal carbides, nitrides, shape memory polymers, poly-pyrrole, poly-dopamine, PDA-modified reduced graphene oxide, CNT / PDMS composite materials, and poly(N-isopropylacrylamide) (PNIPAAm).

[0060] Figure 3a is a conceptual diagram of a light-driven material in the present disclosure.

[0061] Referring to FIG. 3a, in one embodiment of the present disclosure, a stamp (20) may be configured to include an azo-elastomer.

[0062] The molecular structure of azo-elastomers can be changed by a light trigger.

[0063] Specifically, the stamp (20) can change the shape of the molecule by selectively irradiating the wavelength of light using an Azo molecule having an N=N chemical bond. When irradiated with short-wavelength light, a bent cis structure is formed. Conversely, when the Azo molecule is exposed to short-wavelength light, a parallel trans structure is formed. This change in molecular structure due to light appears as a final actuation form and can change the physical shape of the stamp (20).

[0064] Additionally, the azo-elastic polymer may have liquid crystal properties. Additionally, the stamp (20) may be composed of a polymer having elongation deformation properties due to photodeformation.

[0065] In the present disclosure, light of ultraviolet, visible or infrared rays may be used as a trigger for structural deformation of the azo-elastic polymer included in the stamp (20). As an example, the light may have a wavelength of 100 nm to 2000 nm.

[0066] In the present disclosure, the azo-elastic polymer included in the stamp may include at least one of shape memory polyurethane, cross-linked polymer structure, spiropyran, divinylidene, and azo-benzene, or a derivative thereof.

[0067] Hereinafter, the wavelength of light for transforming the azo-elastic polymer into a cis structure is referred to as a first wavelength (λ1), and the wavelength of light for transforming it into a trans structure is referred to as a second wavelength (λ2). That is, when the first light of the first wavelength (λ1) is irradiated onto the stamp (20), it is concavely deformed, and when the second light of the second wavelength (λ2) is irradiated onto the stamp (20), it can be flatly deformed. Here, the size of the first wavelength (λ1) may be smaller than the size of the second wavelength (λ2).

[0068] FIG. 3b and FIG. 3c are conceptual diagrams illustrating a modified example in which the stamp in the present disclosure includes a light-absorbing expansion layer.

[0069] Referring to FIG. 3b, the shape of the stamp can be changed by utilizing the photo-driven elongation characteristic of the present disclosure. As an example, the stamp can include a first layer (20-1) that absorbs light and expands and a second layer (20-2) that does not absorb light. The stamp (20) can be configured by laminating the first layer (20-1) and the second layer (20-2). As described above, the central portion of the stamp can be fixed to the transparent substrate (10) by the fixing member (30).

[0070] Specifically, one side of a flexible two-layer material expands by absorbing light of a selected wavelength, and the opposite layer is made of a material with a small change in expansion coefficient. Through this, the length of expansion increases ( ) can induce a bending-shaped deformation in a structure in which opposite sides of the length (L) maintained by the first layer (20-1) and the second layer (20-2) are joined. When the first layer (20-1) and the second layer (20-2) are configured in a disk shape, when deformed by light, it can be deformed into the shape of a sucker that is concavely formed toward the second layer (20-2). At this time, expansion due to light is possible by including a material that absorbs light of a specific wavelength in the light-absorbing expansion layer. At this time, thermal expansion due to light absorption or light-stimulated expansion is formed.

[0071] At this time, the first layer (20-1), which is a light absorbing layer, may be composed of at least one material selected from the group consisting of carbon nanoparticles, metal nanoparticles, semiconductor nanostructures, transition metal carbides, nitrides, shape memory polymer (SMP), poly-pyrrole, poly-dopamine (PDA), PDA-modified reduced graphene oxide (PDA-RGO), CNT / PDMS composite materials, poly (nisopropylacrylamide) (PNIPAAm), and absorption dye.

[0072] Referring to Fig. 3c, the stamp (20) described in Fig. 3b, which has undergone a bending deformation due to thermal expansion caused by heat generated by light absorption, can return to its original flat structure through thermal contraction through cooling. Specifically, since the shrinkage amount of the first layer (20-1) is greater than the shrinkage amount of the second layer (20-2), it can return to its original flat shape. At this time, cooling of the stamp (20) can be performed using a solvent cooling method such as air cooling and washing (water, IPA).

[0073] FIG. 4a and FIG. 4b are diagrams showing the operating state of the stamp (20) in the present disclosure.

[0074] Referring to Fig. 4a, the central portion of the stamp (20) is fixed to one side of the transparent substrate (10) in a flat state. The peripheral portion of the fixed portion (30) of the stamp (20) may be fixed to or not attached to the transparent substrate (10). As described above, the stamp (20) is composed of an azo-elastomer, and when light of a second wavelength (λ2) is irradiated, it changes to a flat state due to its photodeformation properties.

[0075] Referring to FIG. 4b, when the stamp (20) is irradiated with light of the first wavelength (λ1) due to the photodeformation properties of the azo-elastomer, the outer surface of the stamp (20) is further stretched, thereby changing into the shape of the stamp (20).

[0076] In the present disclosure, when the stamp (20) is deformed by light of the first wavelength (λ1), the lower end of the stamp (20) is brought into close contact with the upper surface of the target (100), and the transparent substrate (10) is pressed toward the target (100) so that the air inside the stamp (20) can be discharged to the outside. At this time, the lower end of the stamp (20) is brought into close contact with the upper surface of the target (100) to seal the internal space. Thereafter, when the transparent substrate (100) is lifted, the target (100) can be stably picked up and fixed by the pressure difference between the inside and the outside of the stamp (20). The fixing force of the stamp (20) can be maintained constant as long as no external force is transmitted. Therefore, even when the stamp (20) picks up the target (100) and moves or aligns the position, stable fixing is possible.

[0077] FIG. 5 is a cross-sectional view of a light-using transfer device (1) according to the second embodiment of the present disclosure.

[0078] Referring to FIG. 5, a light-using transfer device (1) according to a second embodiment of the present disclosure can be configured such that a stamp whose physical shape can be changed by light can be deformed in both directions. For example, a light-blocking layer may be provided at the center, and layers that can be physically deformed by light may be provided on the upper and lower surfaces of the light-blocking layer. In this embodiment, when light of a specific wavelength is irradiated to the upper layer, the upper layer can be deformed, and when light of a specific wavelength is irradiated to the lower layer, the lower layer can be deformed. That is, in this embodiment, the stamp can be deformed symmetrically up and down depending on the light irradiation area.

[0079] In this embodiment, the stamp (20) may be configured to include a plurality of photo-actuator layers. The photo-actuator layer refers to a layer containing a material that undergoes mechanical (or physical) deformation due to the photo-triggered reaction described in the first embodiment. In this embodiment, the photo-actuator layer may exhibit the property of expanding or shrinking due to light. An example of the photo-actuator layer may be a layer containing an azo-elastic polymer.

[0080] In this embodiment, depending on the location, the uppermost layer may be called the first azo-elastomer layer (21), and the lowermost layer may be called the second azo-elastomer layer (23).

[0081] The first azo-elastomer layer (21) may be attached to a lower surface of the substrate through a ring-shaped fixing member (31) on a portion of its upper surface. Since the fixing member (31) is configured in a ring shape, when the second azo-elastomer layer (23) is stretched, the central portion on a plane may move away from the lower surface of the transparent substrate (10). In other words, since the fixing member (31) is configured in a ring shape, the stamp (20) may be convexly deformed toward the target (100).

[0082] A light-blocking layer (22) may be provided between the first azo-elastomer layer (21) and the second azo-elastomer layer (23). The first azo-elastomer layer (21), the second azo-elastomer layer (23), and the light-blocking layer (22) may be attached to each other in a vertical direction.

[0083] In the second embodiment, the shape of the stamp (20) can be more actively transformed into the first shape and the second shape. That is, the stamp (20) can be transformed into a convex shape or a concave shape by irradiating light to selectively elongate or contract the first azo-elastomer layer (21) or the second azo-elastomer layer (23).

[0084] In the second embodiment, the stamp (20) can be deformed into a convex shape, so that the positional accuracy during placement of the target (100) can be improved.

[0085] Figures 6a and 6b are operating state diagrams of the second embodiment.

[0086] Referring to Fig. 6a, when light is irradiated from the lower side of the stamp (20) by the light-blocking layer, light transmission to the first azo-elastomer layer is blocked, and only the second azo-elastomer layer can be selectively deformed. At this time, the stamp (20) can be deformed into a concave shape toward the target (100).

[0087] Conversely, referring to Fig. 6b, when light is irradiated from the upper side of the stamp (20) by the light-blocking layer, light transmission to the second azo-elastomer layer is blocked, and only the first azo-elastomer layer can be selectively deformed. At this time, the stamp (20) can be deformed into a convex shape toward the target (100).

[0088] Fig. 7 is a cross-sectional view of a light-using transfer device (1) according to a third embodiment of the present disclosure.

[0089] In a third embodiment of the present disclosure, unlike the aforementioned embodiments, a plurality of stamps (20) may be used to pick up a single target (100). To this end, the stamps (20) may be configured to be smaller than those in the aforementioned first and second embodiments, and may be arranged in an appropriate number on a transparent substrate (10).

[0090] Figure 8 is an operating state diagram of the third embodiment of the present disclosure.

[0091] Referring to FIG. 8, in the third embodiment, light may be selectively irradiated to some of a plurality of stamps (20) for a pickup or placing process for one target (100). At this time, it is possible to deform the stamps (20) into different shapes by selectively irradiating light among the stamps (20) that pick up one target (100).

[0092] Figures 9a and 9b are usage diagrams of the third embodiment.

[0093] Figures 9a and 9b illustrate the state of the transfer device (1) according to the third embodiment when placing (left) and the target (right) placed on the receiving substrate. The third embodiment of the present disclosure can realign the placed target (100) by picking up a specific part of the target (100). That is, the position of the target (100) can be finely realigned during the transfer process.

[0094] Referring to Fig. 9a, in the present embodiment, when an error occurs in the position of the target (100) (right), the first light is irradiated on some of the stamps (20) among the plurality of stamps (20), and the target (100) can be picked up tilted using only some of the stamps (20). At this time, since the stamp (20) is made of an elastic material, sufficient adhesive force can be exerted up to a certain height even if the target (100) is tilted.

[0095] Referring to FIG. 9b thereafter, when placing is performed by irradiating the second light while aligning the position of the transparent substrate (10), the target (100) is slightly shifted in the horizontal direction and is settled on the receiving substrate (1002) (right). However, this position alignment process is merely an example and can be modified and applied in various ways to selectively operate multiple stamps (20) to adjust the fine position.

[0096] The transfer device according to the present disclosure described above has been described with respect to an example in which the transparent substrate is configured in a planar shape, but may be formed on the outer surface of the drum or configured in a curved shape as illustrated in FIG. 21.

[0097] Hereinafter, a light-based transfer method according to an embodiment of the present disclosure will be described.

[0098] The following examples can be performed using the transcription device described in the first to third examples.

[0099] FIG. 10 is a flowchart of a light-using transfer method according to the fourth embodiment of the present disclosure, and FIGS. 11a and 11b are conceptual diagrams illustrating a concept of transferring a target according to the fourth embodiment.

[0100] Referring to FIG. 10, a light-based transfer method according to a fourth embodiment of the present disclosure may include a step (S110) of picking up a target (100) using a stamp (20) deformed into a concave shape by irradiating a first light of a first wavelength (λ1), a step (S120) of aligning a transfer device to the upper side of a receiving substrate (1002), and a step (S130) of placing the target (100) while deforming the stamp (20) into a flat shape by irradiating a second light of a second wavelength (λ2).

[0101] In this embodiment, the stamp (20) is configured to include a material that can be deformed when light of a specific wavelength is irradiated, as in the first embodiment described above, and when light of different specific wavelengths is irradiated, the molecular structure changes, and ultimately, physical deformation can occur.

[0102] The step (S110) of picking up a target (100) using a stamp (20) deformed into a concave shape by irradiating the first light of the first wavelength (λ1) corresponds to the step of deforming the shape of at least one stamp (20) provided on a transparent substrate (10) into a concave shape toward the target (100) to pick up the target (100) and using the concave stamp (20).

[0103] In relation to this step (S110), referring to FIG. 11a, when the stamp (20) is pressed against the target (100) in a concave state toward the target (100), an adhesive force is generated due to the pressure difference between the inside and outside of the stamp (20).

[0104] The step (S120) of aligning the transfer device to the upper side of the receiving substrate (1002) corresponds to the step of transferring the transparent substrate (10) for placement while the target (100) is picked up by the transfer device. In this step, a precision position control technology widely applied in conventional micro LED manufacturing devices or semiconductor manufacturing devices can be applied for precise position control.

[0105] The step (S130) of placing the target (100) while flattening the stamp (20) by irradiating the second light of the second wavelength (λ2) is performed by irradiating light having a wavelength capable of flattening the stamp (20) through the transparent substrate (10). When the second light is irradiated in this step, the structure of the molecules included in the stamp (20) is deformed and flattened.

[0106] With reference to FIG. 11b in relation to this step (S130), the stamp (20) loses its adhesive force as it is deformed flat, and the target (100) is placed on the receiving substrate (1002) mainly by gravity.

[0107] In the following examples, the physical deformation of the stamp due to light irradiation occurs fairly immediately and reliably. Therefore, the target pickup and placement according to the deformation of the stamp can be performed immediately and reliably.

[0108] Fig. 12 is a flowchart showing the pickup steps in detail in the fourth embodiment, and Fig. 13 is a conceptual diagram showing the pickup process according to the order of Fig. 12.

[0109] Referring to FIG. 12, in the fourth embodiment, the pickup step may be configured to include a step (S111) of irradiating a first light of a first wavelength (λ1) to deform the stamp (20) into a concave shape, and a step (S112) of lowering the transfer device to pick up the target (100) with the stamp (20).

[0110] Referring to Fig. 13, in the present embodiment, a stamp (20) can be first deformed into a concave shape and then picked up. That is, after the stamp (20) is first formed, the horizontal position of the transparent substrate (10) is aligned, and then lowered so that each stamp (20) picks up the target (100).

[0111] Fig. 14 is a flowchart showing in detail another pickup step in the fourth embodiment, and Fig. 15 is a conceptual diagram showing a pickup process according to the order of Fig. 14.

[0112] Referring to FIG. 14, in the fourth embodiment, the pickup step may be configured to include a step (S111') in which the transfer device descends to bring the stamp (20) and the target (100) closer to a predetermined distance, and a step (S111') in which the stamp (20) is deformed into a concave shape by irradiating the first light of the first wavelength (λ1) and the target (100) is picked up.

[0113] That is, unlike the order described with reference to FIG. 12, after aligning the stamp (20) in a horizontal position, the vertical position of the stamp (20) can be adjusted to have a constant distance from the upper surface of the target (100). At this time, the constant distance may be smaller than the height of the stamp (20) when the stamp (20) is completely deformed into a concave shape. Thereafter, when the first light is irradiated on the stamp (20), the shape of the stamp (20) changes to a concave shape and the target (100) is attached at the same time. At this time, the stamp (20) is not completely deformed because the distance in the vertical direction is limited. Thereafter, when the transparent substrate (10) is moved upward, the stamp (20) is completely deformed and the pressure difference between the inside and the outside increases, and the pick-up of the target (100) due to the pressure difference can be completed.

[0114] FIG. 16 is a flowchart of a light-based transfer method according to the fifth embodiment of the present disclosure, and FIGS. 17a, 17b, and 17c are conceptual diagrams illustrating a process of transferring a target according to the fifth embodiment of the present disclosure.

[0115] Referring to FIG. 16, a light-based transfer method according to a fifth embodiment of the present disclosure may be configured to include a step (S211) of aligning a transfer device to a target (100), a step (S212) of selectively irradiating a first light to a predetermined number of stamps (20) using a mask to pick up a predetermined number of targets (100), a step (S220) of aligning the transfer device to the upper side of a receiving substrate, and a step (S230) of placing the target (100) while deforming the stamp (20) into a flat shape by irradiating a second light.

[0116] In this embodiment, it can be performed by selectively changing some of the plurality of stamps (20) provided on the transparent substrate (10). To this end, a mask can be used to selectively irradiate some of the plurality of stamps (20).

[0117] In this embodiment, the step (S211) of aligning the transfer device to the target (100) corresponds to the step of aligning the transparent substrate (10), the mask (40), and the target (100). The mask (40) may have holes formed in a predetermined area for light to pass through. The holes in the mask may be formed corresponding to the position and number of the stamp (20) of the transparent substrate (10) that is to be concavely deformed for pickup.

[0118] The step (S212) of selectively irradiating a first light to a predetermined number of stamps (20) using a mask to pick up a predetermined number of targets (100) corresponds to the step of selectively deforming some of the plurality of stamps (20) into a concave shape by irradiating the first light. At this time, the stamps (20) aligned to the targets (100') that are not transfer targets are maintained in a flat state.

[0119] In this step, the target (100) can be picked up from the donor substrate (1001) after the stamp (20) is concavely deformed as described with reference to FIG. 12, or the target (100) can be picked up from the donor substrate (1001) during the process of concavely deforming the stamp (20) as described in FIG. 14.

[0120] The step (S220) of aligning the transfer device to the upper side of the receiving substrate corresponds to a step of aligning the transparent substrate (10) and at least one picked-up target (100) horizontally to the upper side of the receiving substrate, and also aligning the target (100) in the vertical direction through height adjustment.

[0121] The step (S230) of placing the target (100) while deforming the stamp (20) into a flat shape by irradiating the second light corresponds to the step of deforming the stamp (20) into a flat shape and placing the target (100) on the receiving substrate (1002). In this step, the stamps (20) irradiated with the second light are deformed into a flat shape. Therefore, for selective placing, selective irradiation of the second light using a mask or the like is required. However, when placing multiple targets (100) at once, the second light can be irradiated to the entire target without a mask.

[0122] Meanwhile, in the present embodiment, the step (S211) of aligning the transfer device to the target (100) may be performed by flattening the initial state of all stamps (20) and then irradiating the first light on some stamps (20) to deform them concavely (Fig. 17a), and conversely, after concavely deforming the initial state of all stamps (20), irradiating the second light on stamps (20) matching the target (100') not to be picked up and deforming them flatly.

[0123] According to the method performed in this embodiment, different types of targets (100) can be transferred and transferred one by one. For example, if micro LEDs are classified into three types, red, green, and blue, the red micro LED can be picked up in a specific pattern and transferred to the receiving substrate. Thereafter, the green micro LED and the blue micro LED can be picked up in a specific pattern and transferred, respectively.

[0124] Fig. 18 is a flowchart of a light-using transfer method according to the sixth embodiment of the present disclosure.

[0125] Referring to FIG. 18, a light-based transfer method according to a sixth embodiment of the present disclosure may be configured to include a step of aligning a transfer device to a first target (S311), a step of selectively irradiating a first light to a predetermined number of stamps to pick up a predetermined number of first targets (S312), a step of aligning a transfer device to a second target (S313), a step of selectively irradiating a first light to a predetermined number of other stamps to pick up a predetermined number of second targets (S314), a step of aligning a transfer device to an upper side of a receiving substrate (S320), and a step of placing the first target and the second target while deforming the stamp into a flat shape by irradiating a second light of a second wavelength (S330).

[0126] In this embodiment, a transfer device is configured to sequentially pick up different targets and simultaneously place them.

[0127] Each stamp picks up a first target or a second target, and light can be selectively irradiated to the stamp to induce deformation in the stamp to be picked up for each pickup. In the present embodiment, different masks can be used to selectively irradiate light to the first and second targets, or the same mask can be used when picking up the first and second targets to pick up the same pattern among the stamp arrays. At this time, in the step of aligning the transfer device to the second target, the position of the mask can be precisely aligned to select a different stamp to be deformed.

[0128] Figures 19a, 19b, 19c and 19d are conceptual diagrams illustrating the picking process according to the order of Figure 18.

[0129] Figures 19a to 19d illustrate a process of picking up a first target (101), a second target (102), and a third target (103) according to the order of Figure 18. This example can be understood as a process of transferring a red micro LED, a green micro LED, and a blue micro LED.

[0130] Referring to Fig. 19a, in order to pick up a first target (101), a first light having a first wavelength (λ1) is selectively irradiated to the first stamps (20-1) according to the holes of the first pattern formed in the first mask (41). Then, the first target (101) is picked up using each of the first stamps (20-1).

[0131] Referring to Fig. 19b, in order to pick up the second target (102), the second stamps (20-2) are selectively irradiated with the first light of the first wavelength (λ1) according to the holes of the second pattern formed in the second mask (42). At this time, the position of the same mask can be precisely adjusted to select a stamp that operates with the same pattern. In addition, a stamp that operates can be selected using a mask different from that of Fig. 19a.

[0132] Referring to Fig. 19c, a first light having a first wavelength (λ1) is irradiated onto some stamps using a third mask (43) so that a third target (103) can be picked up similarly to the first target (101) and the second target (102). Then, the transparent substrate is lowered to pick up the third target (103) using the third stamps (20-3).

[0133] Referring to Fig. 19d, the first target (101), the second target (102), and the third target (103) that are picked up by forming a pattern on a transparent substrate are aligned to the receiving substrate. Then, by irradiating the entire stamp with a second light of a second wavelength (λ2), the adhesive force is released, and the first target (101), the second target (102), and the third target (103) can be placed simultaneously.

[0134] Figure 20 is a flowchart of a light-using transfer method according to the seventh embodiment of the present disclosure.

[0135] Referring to FIG. 20, the seventh embodiment of the present disclosure can be performed using a drum that rotates the pickup and placing steps.

[0136] The seventh embodiment may include a step (S410) of picking up a target using a stamp deformed into a concave shape by irradiating a first light of a first wavelength while rotating the drum, a step (S420) of aligning a transfer device to an upper side of a receiving substrate, and a step (S430) of placing the target while deforming the stamp into a flat shape by irradiating a second light of a second wavelength while rotating the drum.

[0137] Fig. 21 is a conceptual diagram illustrating a step of picking up a target (100) in the seventh embodiment. Referring to Fig. 21, in this embodiment, the picking up or placing of the target (100) can be performed while the drum (50) rotates and the drum and the donor substrate (1001) or the receiving substrate (not shown) move relatively horizontally.

[0138] The drum (50) used in the seventh embodiment is provided with a transparent substrate (10) on its outer surface, and a light source may be provided on the inner or outer surface of the drum (50). On the outer surface of the transparent substrate (10), a stamp (20) formed to be concave toward the outside may be provided along the outer circumference. In this case, the stamp (20) may be capable of irreversible deformation between a flat state and a concave state as described above.

[0139] Meanwhile, although not shown, the step (S430) of placing the target (100) in the seventh embodiment may be performed similarly to the step (S410) of picking up the target (100) by rotating the drum (50) and horizontally moving the receiving substrate, and by irradiating the stamp (20) moved to the placing position with the second light of the second wavelength.

[0140] As described above, the light-using transfer device and transfer method using the same according to the present disclosure can perform pickup and placing using a stamp whose shape can be reversibly changed, thereby ensuring speed, stability, and reliability for transferring micro LEDs.

Claims

1. A light-transmitting transparent substrate; and A light-using transfer device comprising at least one stamp provided on one surface of the transparent substrate and configured to enable a reversible change between a first form and a second form when irradiated with light.

2. In paragraph 1, The above stamp, When light of the first wavelength is irradiated, it changes into the first form, A transfer device that uses light that changes into the second form when irradiated with light of a second wavelength.

3. In paragraph 2, The above stamp, When light of the first wavelength is irradiated, it is deformed concavely, A transfer device that uses light that is flatly transformed when irradiated with light of the second wavelength.

4. In paragraph 3, A transfer device using light, wherein the first wavelength and the second wavelength are selected from wavelengths of ultraviolet light, visible light or infrared light.

5. In paragraph 3, A transfer device using light, wherein the first wavelength and the second wavelength are selected from 100 nm to 2000 nm.

6. In paragraph 3, The above stamp, A light-assisted transfer device comprising an azo-elastomer exhibiting photo-chemical conversion actuation characteristics having a structure of 'RN=N-R'.

7. In paragraph 6, The above azo-elastomer is a light-based transfer device comprising a mesogenic molecular structure having liquid crystal properties.

8. In paragraph 6, The above azo-elastomer is a light-using transfer device having a molecular structure including at least one of shape memory polyurethane, cross-linked polymer structure, spiropyran, divinylidene and azo-benzene, or a derivative thereof.

9. In paragraph 3, The above stamp is a light-using transfer device comprising at least two layers containing different materials having a large or small coefficient of thermal expansion and exhibiting photothermal conversion actuation characteristics.

10. In paragraph 3, The above stamp is a light-using transfer device comprising a material that exhibits a change in strain characteristics that expands or contracts due to light, and is composed of a single-layer or multi-layer structure.

11. In paragraph 6, The above stamp, A light-based transfer device comprising at least one of carbon nanoparticles, metal nanoparticles, semiconductor nanostructures, transition metal carbides, nitrides, shape memory polymers, poly-pyrrole, poly-dopamine, PDA-modified reduced graphene oxide, CNT / PDMS composite materials, and poly(N-isopropylacrylamide)(PNIPAAm).

12. In paragraph 7, The above stamp, When flattened, it has a disc-like shape. A light-using transfer device in which a portion of the central surface is bonded to the transparent substrate.

13. In paragraph 3, The above stamp, When the first light of the first wavelength is irradiated, the target is picked up while being concavely deformed. A light-using transfer device that places the target while being flatly deformed when irradiated with a second light of the second wavelength.

14. In paragraph 9, The above stamp, First photo-actuator layer; light-blocking layer; and A light-based transfer device formed by laminating a second photo-actuator layer.

15. In a transfer method using a transfer device equipped with a stamp facing the target, A step of picking up the target using the stamp deformed into a concave shape by irradiating the first light of the first wavelength; a step of aligning the above transfer device to the upper side of the receiving substrate; and A light-based transfer method comprising the step of placing the target while deforming the stamp into a flat shape by irradiating the stamp with a second light of a second wavelength.

16. In paragraph 15, The above stamp, A light-based transfer method comprising a placing step in which the concave shape and the flat state are reversibly changed.

17. In paragraph 16, The above picking up steps are: In the process of the above stamp changing into the above concave shape, the target is attached to the above stamp, A light-based transfer method for attaching the target to the stamp by lowering the transparent substrate after the stamp is deformed into the concave shape.

18. In paragraph 17, A transfer method using light, wherein the first wavelength and the second wavelength are selected from wavelengths of ultraviolet light, visible light or infrared light.

19. In paragraph 18, A transfer method using light, wherein the first wavelength and the second wavelength are selected from 100 nm to 2000 nm.

20. In paragraph 19, The above stamp comprises an azo-elastomer having the structure RN=N-R', The above azo-elastomer is a light-based transfer method comprising a mesogenic molecular structure having liquid crystal properties.

21. In paragraph 19, The stamp is a light-based transfer device including at least one of carbon nanoparticles, metal nanoparticles, semiconductor nanostructures, transition metal carbides, nitrides, shape memory polymers, polypyrrole, polydopamine, PDA-modified reduced graphene oxide, CNT / PDMS composite materials, and poly(N-isopropylacrylamide; PNIPAAm) exhibiting light-induced expansion or contraction properties.

22. In paragraph 20, The above-mentioned transcription device includes a light-transmitting substrate, The above stamps are composed of multiple stamps and are arranged on one side of the transparent substrate, A light-based transfer method, wherein the picking up step and the placing step are performed by selectively irradiating light onto at least one of the stamps.

23. In paragraph 22, The above picking up step and the above placing step are, A light-using transfer method that selectively irradiates the stamp with light using a mask having a light-transmitting hole formed on the upper side of the transparent substrate.

24. In paragraph 22, The above picking step selectively irradiates the first light to the predetermined number of the stamps so that a predetermined number of the targets can be picked up simultaneously, The above-mentioned placing step is a light-using transfer method that selectively irradiates the second light to the predetermined number of stamps.

25. In paragraph 22, The above picking up steps are: A first pickup step for selectively irradiating the first light onto a predetermined number of the stamps so as to simultaneously pick up a predetermined number of the first targets; A position alignment step for aligning positions to simultaneously pick up a predetermined number of second targets; and Including a second pickup step of selectively irradiating the first light to the predetermined number of other stamps to simultaneously pick up the predetermined number of second targets in the above-mentioned aligned state, The above playing steps are: A light-using transfer method that simultaneously irradiates the second light to a plurality of the stamps so that the first target and the second target that have been picked up can be placed simultaneously.

26. In paragraph 20, The above-mentioned transcription device includes a drum, The outer surface of the above drum is provided with a light-transmitting substrate, The above stamps are arranged along the outer surface of the light-transmitting substrate, A light-based transfer method in which the above pickup step and the above placing step are performed together with the rotation of the drum.

27. In paragraph 20, The above stamp is configured to be smaller than the above target, A light-based transfer method wherein a plurality of said stamps are configured to pick up said target.

28. In paragraph 1, The above target is a light-based transfer method for electronic components in the form of chips.

29. In paragraph 1, The above target is a light transfer method using a semiconductor or micro LED.

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