Method and device for transferring micro devices and electronic products using the method and device

Abstract

An exemplary embodiment of the present invention provides a method for transferring microdevices, which is applicable to more different microdevices and can improve transfer efficiency. An exemplary embodiment of the present invention provides a method for transferring microdevices. The method for transferring microdevices includes: conveying a target substrate in a first direction at a first rate; setting the microdevice bonded to the transfer film to face the upper portion of the target substrate, and supplying the transfer film in the first direction; separating the transfer film from the microdevice transferred to the target substrate, and bending the transfer film upward to form a curved arc, and pressurizing the upper transfer film conveyed after the curved arc is formed by a pressure roller rotating on the upper side of the target substrate, and transferring the pressure to the lower transfer film bonded to the microdevice and supplied; and conveying and collecting the upper transfer film conveyed after the curved arc is formed in a second direction opposite to the first direction at a second rate, wherein the first center of the curved arc is formed on the front side of the second center of the pressure roller based on the first direction.

Description

Technical Field

[0001] The present invention relates to a method and apparatus for transferring microdevices, and an electronic product using the method and apparatus, and more specifically, to a method and apparatus for transferring microdevices, which are applicable to more different microdevices and can improve transfer efficiency, and to an electronic product including the microdevices transferred by using the transfer method. Background Art

[0002] As the next generation of advanced displays to replace existing displays, displays using micro LED devices are attracting attention. In order to manufacture displays, the technology of transferring micro LED devices to circuit boards is the core.

[0003] Large and thick components can be transferred by other methods such as vacuum chucks, but methods for transferring small and thin components with micron / nano sizes are limited. Micro devices with tens of microns or less may be damaged due to the pressure generated in the vacuum chuck, making it difficult to use the vacuum chuck. As another method, there is a method of transferring a device by using an electrostatic chuck technology, but when this method is applied to a thin device, the device may be damaged by static electricity, and the transfer performance may be reduced by the influence of contaminants on the surface of the device.

[0004] Due to the above reasons, for devices in the form of thin films having a very small thickness, a technique of transferring the devices by using an adhesive force is widely used.

[0005] Generally, a micro device array arranged on a source substrate is bonded to a transfer film by a method of transferring micro devices using an adhesive force, and the micro devices are transferred to a solder applied to an electrode of a target substrate.

[0006] The transfer method can be generally divided into a method using a roller and a method using a pressurizing plate according to a scheme for pressing the micro device to the target substrate. The transfer method using a roller has an advantage in improving the productivity of a large-scale production process.

[0007] Figure 1 is a diagram showing an example of a method of transferring a micro device by using a roller in the related art.

[0008] like Figure 1 As shown, the transfer film 10 is directly pressurized by the pressurizing roller 20 , and thus, pressure is applied to the micro device 30 bonded to the transfer film 10 , so that the micro device 30 is transferred to the target substrate 40 .

[0009] In this method, it is difficult to accurately control the pressure applied to the target substrate 40 by the pressure roller 20. That is, when the pressure of the pressure roller 20 is too small, the transfer may not be performed, and when the pressure of the pressure roller 20 is too large, the contact area between the pressure roller 20 and the target substrate 40 increases, thereby reducing the transfer efficiency and damaging the micro device 30.

[0010] When the size of the micro device is small, it is more difficult to accurately control the pressure of the pressure roller 20. In order to control the contact area between the pressure roller 20 and the target substrate 40 to be suitable for the size of the device, the diameter of the pressure roller 20 needs to be small, but there is a limit in reducing the diameter of the pressure roller 20. When the size of the micro device is small and the interval between the micro devices bonded to the source substrate is simultaneously reduced, it becomes more difficult to accurately control the pressure of the pressure roller 20.

[0011] This phenomenon is a problem generated in a method of pressurizing a micro device by using a pressurizing plate.

[0012] Furthermore, new technologies are needed to efficiently transfer further miniaturized microdevices.

[0013] Public Content

[0014] Technical issues

[0015] The present invention is dedicated to providing a method for transferring a micro-device, which is applicable to more different micro-devices and can improve the transfer efficiency.

[0016] The present invention is also directed to providing a device for transferring micro-devices, which is applicable to more different micro-devices and can improve transfer efficiency.

[0017] The present invention is also directed to providing an electronic product including a micro device transferred by using the transfer method.

[0018] The technical objectives that the present invention aims to achieve are not limited to the aforementioned technical objectives, and those skilled in the art can clearly understand other unmentioned technical objectives from the following description.

[0019] Technical Solutions

[0020] An exemplary embodiment of the present invention provides a method for transferring a micro device, the method comprising: conveying a target substrate in a first direction at a first rate; supplying a transfer film combined with the micro device in the first direction, the micro device facing an upper portion of the target substrate; pressurizing the transfer film, the pressurizing comprising bending the transfer film separated from the micro device upward to form a curved arc, and pressurizing the upper transfer film conveyed after the curved arc is formed with a pressurizing roller rotating on the upper side of the target substrate to transfer the pressure to a lower transfer film combined with the micro device; and collecting the upper transfer film by conveying the upper transfer film conveyed after the curved arc is formed along a second direction opposite to the first direction at a second rate, wherein, based on the first direction, a first center of the curved arc is located in front of a second center of the pressurizing roller.

[0021] In an exemplary embodiment of the present invention, a separation distance between an upper surface of the micro device transferred to the target substrate and a lower end portion of the pressing roller may exceed twice the thickness of the transfer film.

[0022] In an exemplary embodiment of the present invention, the linear speed of the pressure roller, the second rate, and the first rate may be the same.

[0023] In an exemplary embodiment of the present invention, the method may further include a first control for adjusting a radius of curvature of the curved arc by adjusting a linear speed of the pressure roller within a predetermined time.

[0024] In an exemplary embodiment of the present invention, the first control may include: a first curvature radius adjustment, in which the curvature radius of the curved arc is controlled to decrease by increasing the linear speed of the pressure roller and moving the position of the first center of the curved arc to the rear side based on the first direction, or the curvature radius of the curved arc is controlled to increase by reducing the linear speed of the pressure roller and moving the position of the first center of the curved arc to the front side based on the first direction.

[0025] In an exemplary embodiment of the present invention, the first control may further include a first speed adjustment after the first curvature radius adjustment, in which the first speed and the second speed are controlled to be the same as the linear speed of the pressing roller adjusted in the first curvature radius adjustment.

[0026] In an exemplary embodiment of the present invention, the method may further include a second control for adjusting a curvature radius of the curved arc by adjusting a first velocity of the target substrate within a predetermined time.

[0027] In an exemplary embodiment of the present invention, the second control may include: a second curvature radius adjustment, in which the curvature radius of the curved arc is controlled to increase by increasing the first speed of the target substrate and moving the position of the first center of the curved arc to the front side based on the first direction, or the curvature radius of the curved arc is controlled to decrease by decreasing the first speed of the target substrate and moving the position of the first center of the curved arc to the rear side based on the first direction.

[0028] In an exemplary embodiment of the present invention, the second control may further include a second velocity adjustment after the second curvature radius adjustment in which the linear speed and the second velocity of the pressing roller are controlled to be equal to the first velocity of the target substrate adjusted in the second curvature radius adjustment.

[0029] In an exemplary embodiment of the present invention, pressurizing may include imparting additional pressure to the lower transfer film via a pressurizing rod disposed within a curved arc formed by the transfer film.

[0030] In an exemplary embodiment of the present invention, in the pressurizing, when the pressurizing roller presses the upper transfer film, the upper transfer film may be in contact with the lower transfer film.

[0031] Another exemplary embodiment of the present invention provides an apparatus for transferring microdevices, the apparatus comprising: a supply roller configured to supply a transfer film combined with the microdevice in a first direction; a target substrate to which the microdevice is transferred from the supplied transfer film when the microdevice is conveyed in the first direction; a pressure roller disposed at an upper portion of the target substrate and configured to pressurize the transfer film separated from the microdevice; and a collecting roller configured to collect the transfer film, wherein the transfer film that transfers the microdevice to the target substrate moves in a second direction opposite to the first direction while bending upward and forming a curved arc, and the center of the pressure roller is arranged on the rear side of the center of the curved arc, and the pressure roller presses the transfer film moving in the second direction in a downward direction while forming the curved arc.

[0032] In an exemplary embodiment of the present invention, the apparatus may further include a pressurizing rod disposed within a curved arc formed by the transfer film.

[0033] In an exemplary embodiment of the present invention, the transfer film may include: a base layer having rigidity; and an adhesive layer disposed on one surface of the base layer to provide adhesive force to the micro device, and the adhesive layer separated from the micro device may contact a pressure roller to provide friction force.

[0034] In an exemplary embodiment of the present invention, the transfer film may further include a lubricating layer disposed on the other surface of the base layer so that the transfer films before and after the curved arc is formed contact each other and are moved.

[0035] Yet another exemplary embodiment of the present invention provides an electronic product including a micro device transferred by using the method of transferring a micro device.

[0036] Beneficial Effects

[0037] According to an exemplary embodiment of the present invention, a pressure roller is pressurized to a transfer film (i.e., an upper transfer film not combined with a micro device). Then, by the rigidity of the curved transfer film, the pressure is transmitted to the transfer film, i.e., the lower transfer film combined with the micro device, and the micro device is pressurized to the target substrate by pressure. Then, by adjusting the radius of curvature of the curved arc of the film, the pressure can be easily controlled in the advancement of the transfer process. In addition, the rigidity of the transfer film can be changed according to the properties, thickness, and shape (such as a multilayer structure) of the film material, and can be selected to be suitable for the process. Therefore, the pressure can be accurately controlled, which is difficult to achieve in the case of the transfer film to which the pressure roller directly pressurizes the micro device in the related art, and the pressure is buffered by the flexibility of the transfer film. Therefore, the transfer efficiency can be improved and the micro device can be effectively prevented from being damaged due to pressure.

[0038] Furthermore, according to an exemplary embodiment of the present invention, when the size of micro devices bonded to a transfer film and the intervals between micro devices are changed, the pressure to be provided to the micro devices can be precisely adjusted by adjusting the linear speed of the pressurizing roller or adjusting the conveying rate of the target substrate.

[0039] The effects of the present invention are not limited to the aforementioned effects, and it should be understood that the effects of the present invention include all effects that can be inferred from the configuration of the present invention described in the detailed description of the present invention or the claims. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] Figure 1 is a diagram showing an example of a method of transferring a micro device by using a roller in the related art.

[0041] Figure 2 is a flowchart of a method of transferring a micro device according to a first exemplary embodiment of the present invention.

[0042] Figure 3 : is a diagram showing an example of a transfer process of the method of transferring a micro device according to the first exemplary embodiment of the present invention.

[0043] Figure 4 is a diagram showing an example of an enlarged main part of a transfer process of the method of transferring a micro device according to the first exemplary embodiment of the present invention.

[0044] Figure 5 is a flowchart illustrating control in the method of transferring a micro device according to the first exemplary embodiment of the present invention.

[0045] Figure 6 and Figure 7 : is a diagram showing an example for describing control in the method of transferring a micro device according to the first exemplary embodiment of the present invention.

[0046] Figure 8 : is a diagram showing an example of a transfer process of a method of transferring a micro device according to a second exemplary embodiment of the present invention.

[0047] Fig. 9 is a diagram showing an example of an enlarged main part of a transfer process of a method of transferring a micro device according to a third exemplary embodiment of the present invention.

[0048] Fig.10 is a diagram showing an example of an enlarged main part of a transfer process of a method of transferring a micro device according to a fourth exemplary embodiment of the present invention.

[0049] Invention Mode

[0050] The present invention will be described below with reference to the accompanying drawings. Those skilled in the art will recognize that all embodiments described may be modified in various ways without departing from the spirit or scope of the present invention. Accordingly, the accompanying drawings and descriptions are considered to be illustrative rather than restrictive in nature. Throughout the specification, similar reference numerals represent similar elements.

[0051] Throughout the specification, when it is described that a component is "connected (contacted, coupled)" to another component, the component may be "directly connected" to the other element or "connected" to the other component through a third component. In the specification, unless explicitly described to the contrary, the word "include" and variations such as "include" or "comprising" will be understood to imply the inclusion of the stated elements but not the exclusion of any other elements.

[0052] In addition, the terms used in this specification are used to simply explain specific exemplary embodiments and are not intended to limit the present invention. Singular expressions include plural expressions unless there is a specific description to the contrary in the context. In this specification, it should be understood that the terms "including" and "having" are intended to represent the existence or combination of the features, quantities, steps, operations, constituent elements, and parts described in the specification, and do not exclude the possibility of pre-existing or adding one or more other features, quantities, steps, operations, constituent elements, and parts, or combinations thereof.

[0053] Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

[0054] Figure 2 is a flowchart showing a method of transferring a micro device according to a first exemplary embodiment of the present invention, and Figure 3: is a diagram showing an example of a transfer process of the method of transferring a micro device according to the first exemplary embodiment of the present invention.

[0055] like Figure 2 and Figure 3 As shown, the method of transferring a micro device may include conveying S110 , supplying S120 , pressurizing S130 , and collecting S140 .

[0056] The conveying S110 may be a step for conveying the target substrate 200 in the first direction A1 at a first velocity V1.

[0057] The target substrate 200 may be a substrate to which the micro device 300 will be transferred. Figure 4 ) may be disposed on the target substrate 200, and the solder 220 (see Figure 4 ) may be prepared on the upper surface of the first electrode 210.

[0058] The target substrate 200 may be a solid substrate or a flexible substrate.

[0059] The supplying S120 may be a step for disposing the micro device 300 bonded to the transfer film 400 to face the upper portion of the target substrate 200 and supplying the transfer film 400 in the first direction A1.

[0060] The micro device 300 may be in a state of being bonded to the lower surface of the transfer film 400 at a predetermined interval. The transfer film 400 to which the micro device 300 is bonded may be prepared in a state of being wound around the supply roller 510 .

[0061] For this purpose, this needs to be performed before the process of transferring the micro devices of the source substrate (not shown) to the transfer film 400 .

[0062] The transfer film 400 wound around the supply roller 510 may be supplied in the first direction A1 in which the target substrate 200 is conveyed, and in this case, the micro device 300 may be disposed to face the upper portion of the target substrate 200. The second electrode 310 (see Figure 4 ) may be disposed at a lower portion of the micro device 300 .

[0063] In the supplying S120, the second electrode 310 of the micro device 300 to be transferred to the target substrate 200 may be in a state of being temporarily bonded to the solder 220 of the first electrode 210 of the target substrate 200. Therefore, the supply rate VS of the transfer film 400 supplied in the first direction A1 may be the same as the first rate V1 which is the conveying rate of the target substrate 200.

[0064] Pressurizing S130 may be a step in which the transfer film 400 is separated from the micro device 300a transferred to the target substrate 200 and then bent toward the upper side to form a curved arc 410, and the upper transfer film 400b conveyed after the curved arc 410 is formed is pressurized by a pressurizing roller 520 rotating on the upper side of the target substrate 200, and the pressure is transmitted to the lower transfer film 400a combined with the micro device 300 and conveyed.

[0065] That is, the transfer film 400 may include a lower transfer film 400a supplied in the first direction A1 in a state of being combined with the micro device 300 and an upper transfer film 400b bent toward the upper side to form a curved arc 410 and then conveyed in the second direction A2.

[0066] In the pressing S130, when the upper transfer film 400b is pressed in the downward direction by the pressing roller 520, the pressure may be transmitted to the lower transfer film 400a by the rigidity of the transfer film 400. Then, the pressure is also transmitted to the micro device 300a through the lower transfer film 400a, so that the micro device 300a may be pressed to the target substrate 200.

[0067] The collecting step S140 may be a step in which the upper transfer film 400 b conveyed after the curved arc 410 is formed is conveyed in a second direction A2 opposite to the first direction A1 at a second speed V2 and is collected.

[0068] The conveying S110, the supplying S120, the pressing S130 and the collecting S140 are not performed sequentially but can be performed simultaneously. In addition, the linear velocity of the pressing roller 520 in a stable state, the second rate V2 and the first rate V1 can have the same magnitude. Here, the linear velocity can be the linear velocity of the surface through which the pressing roller 520 rotates. Therefore, the supplying and collecting of the transfer film 400 can be performed continuously while continuously forming the curved arc 410 with the same radius of curvature at the same position, and the micro device 300 can also be continuously transferred.

[0069] The size of the radius of curvature of the curved arc 410 can be adjusted according to the size of the transferred micro-device. That is, when the size of the transferred micro-device is small, the size of the radius of curvature of the curved arc 410 can be small, and when the size of the transferred micro-device is large, the size of the radius of curvature of the curved arc 410 can be large. Therefore, even small-sized micro-devices can be accurately transferred to pressure.

[0070] Meanwhile, a setting operation for performing a micro device transfer process will be described below.

[0071] In the setting operation, when the operator presses one end portion of the transfer film 400 wound around the supply roller 510 and pulls the transfer film 400 in the first direction A1, the transfer film 400 may be supplied in the first direction A1. Then, the curved arc 410 may be formed by bending the transfer film 400 toward the upper side at a point where the transfer film 400 passes through the pressure roller 520 based on the first direction A1, and then the transfer film 400 may be connected to the collecting roller 530 by pulling the transfer film 400 in a second direction A2 opposite to the first direction A1.

[0072] The supply roller 510 may be provided to freely rotate based on a central axis, and the collecting roller 530 may receive power and rotate, so that the transfer film 400 is wound.

[0073] Therefore, when the target substrate 200 is conveyed in the first direction A1 at the first speed V1 and the collecting roller 530 rotates, the lower transfer film 400a is conveyed in the first direction A1 based on the curved arc 410, and the upper transfer film 400b is conveyed in the second direction A2 to be collected.

[0074] Then, by adjusting the linear speed of the collecting roller 530, the second speed V2 is adjusted to have the same magnitude as the first speed V1, and the linear speed of the pressing roller 520 is adjusted to have the same magnitude as the second speed V2, so that the conveyance of the target substrate 200 and the transfer film 400 and the rotation of the pressing roller 520 can be maintained in a stable state. In addition, when the conveyance of the target substrate 200 and the transfer film 400 and the rotation of the pressing roller 520 are maintained in a stable state, the micro device 300 can be continuously transferred.

[0075] Figure 4 is a diagram showing an example of an enlarged main part of a transfer process of the method of transferring a micro device according to the first exemplary embodiment of the present invention.

[0076] Hereinafter, for convenience of description, the front and rear directions will be described based on the first direction A1 as the conveying direction of the target substrate 200. That is, when the target substrate 200 moves from a first point to a second point, the first point is the rear direction and the second point is the front direction.

[0077] like Figure 4 As shown, a spacing distance D1 between the upper surface of the micro device 300 a transferred to the target substrate 200 and the lower end portion of the pressing roller 520 may exceed twice the thickness T of the transfer film 400 .

[0078] Then, based on the first direction A1, a first center C1 of the curved arc 410 may be formed in front of a second center C2 of the pressure roller 520.

[0079] The radius of curvature R of the curved arc 410 can be adjusted by adjusting the control distance D2 between the first center C1 and the second center C2. That is, when the first center C1 of the curved arc 410 is positioned toward the rear direction based on the first direction A1, the radius of curvature R of the curved arc 410 can be reduced. Then, when the first center C1 of the curved arc 410 is positioned toward the front direction based on the first direction A1, the radius of curvature R of the curved arc 410 can be increased.

[0080] When the transfer film 400 is conveyed so as to be collected, the second rate V2 may have the same magnitude as the first rate V1 which is the conveying rate of the target substrate 200. Therefore, the supply rate VS at which the transfer film 400 is supplied in the first direction A1 in which the target substrate 200 is conveyed may have the same magnitude as the first rate V1 which is the conveying rate of the target substrate 200.

[0081] In addition, the linear velocity VL of the pressure roller 520 may be the same as the second velocity V2, which is the velocity at which the transfer film 400 is collected. Therefore, in a stable state that can provide a pressure suitable for transferring the corresponding micro device 300 to the target substrate 200, the transfer film 400 may be conveyed so that a curved arc 410 having a predetermined radius of curvature R is formed to provide uniform pressure, and the micro device 300a may be stably transferred.

[0082] The transfer film 400 may have a first layer 401 and a second layer 402 .

[0083] The base layer 401 can provide rigidity for the lower transfer film 400a, so that when the upper transfer film 400b is pressed by the pressure roller 520, pressure is generated in the downward direction. In other words, the base layer 410 can have resistance to deformation or form a restoring force, so that the magnitude of the pressure generated by the lower transfer film 400a in the downward direction can be controlled according to the properties of the material of the base layer 410.

[0084] In addition, the adhesive layer 402 can provide an adhesive force so that the micro devices 300 and 300a are combined. When the transfer film 400 is bent upward to form a curved arc 410 and then transported along the second direction A2, the adhesive layer 402 can be in close contact with the pressure roller 520. By the adhesive force of the adhesive layer 402, no slip is generated between the pressure roller 520 and the adhesive layer 402, and therefore, the size of the linear velocity VL of the pressure roller 520 can be the same as the size of the second speed V2 of the upper transfer film 400b. In addition, the second speed V2 of the upper transfer film 400b can be adjusted by adjusting the linear velocity of the pressure roller 520, which will be described below.

[0085] In the method of transferring a micro device in the related art, a pressure roller 20 directly presses a transfer film 10 to which a micro device 30 is bonded to allow the micro device 30 to be transferred to a target substrate 40 (see FIG. Figure 1 ).

[0086] However, according to the present invention, the pressure roller 520 pressurizes the transfer film (i.e., the upper transfer film 400b to which the micro device 300 is not bonded). Then, due to the rigidity of the curved transfer film, the pressure is transmitted to the transfer film (i.e., the lower transfer film 400a to which the micro device 300 is bonded), and the micro device 300a can be pressurized and transferred to the target substrate 200 due to the pressure.

[0087] Therefore, as described above, the present invention can accurately control the pressure and buffer pressure, which is difficult to achieve in the case where the pressure roller directly presses the transfer film to which the micro device is bonded in the related art, and therefore, can improve the transfer efficiency and effectively prevent the micro device 300 from being damaged due to pressure.

[0088] In addition, the pressure roller 520 may be controlled to change the vertical position. In addition, an adhesive layer (not shown) may be coated on the outer peripheral surface of the pressure roller 520 to further improve adhesion with the adhesive layer 402 of the transfer film 400 .

[0089] Figure 5 is a flowchart showing control in a method of transferring a micro device according to a first exemplary embodiment of the present invention, and Figure 6 and Figure 7 : is a diagram showing an example of control for describing a method for transferring a micro device according to a first exemplary embodiment of the present invention. Here, Figure 6 The case where the curvature radius of the curved arc is adjusted by adjusting the linear speed of the pressure roller is described. Figure 7 A case where the curvature radius of the curved arc is adjusted by adjusting the conveying rate of the target substrate is described.

[0090] First, refer to Figure 5 and Figure 6 The method of transferring a micro device may further include a first control S150, wherein the curvature radius of the curved arc is adjusted by adjusting the linear speed of the pressure roller, and the first control S150 may include a first curvature radius adjustment S151 and a first speed adjustment S152.

[0091] Here, the first curvature radius adjustment S151 can be an operation in which, within a predetermined time, the linear speed of the pressure roller is increased and the position of the first center of the curved arc is moved toward the rear direction based on the first direction A1 to control the curvature radius of the curved arc to decrease, or the first curvature radius adjustment S151 can be an operation in which, within a predetermined time, the linear speed of the pressure roller is increased and the position of the first center of the curved arc is moved toward the front direction based on the first direction A1 to control the curvature radius of the curved arc to increase.

[0092] That is to say, Figure 6 As shown in (a), when the target substrate 200 is conveyed at a first conveying rate V1a, the pressure roller 520 rotates at a first linear velocity VLa, and the transfer film 400 is supplied at a first supply rate VSa and collected at a first collection rate V2a, the curved arc 410 may have a first curvature radius R1.

[0093] In addition, if Figure 6 As shown in (b), when the linear velocity of the pressure roller 520 increases to a second linear velocity VLb greater than the first linear velocity VLa, the conveying rate of the upper transfer film 400b may be increased at a portion that is in close contact with the pressure roller 520 and is pressurized to the pressure roller 520 by the friction force with the pressure roller 520. At the same time, the conveying rate of the lower transfer film 400a maintains the first supply rate VSa, so that the position of the first center C1 of the curved arc 410 may be moved in a rear direction based on the first direction A1 as the conveying direction of the target substrate 200, and the curved arc 410 may have a second curvature radius R2 that is smaller than the first curvature radius R1.

[0094] Here, within a predetermined time, the linear velocity of the pressure roller 520 may be increased to the second linear velocity VLb. In addition, during this period, the collection rate of the upper transfer film 400b maintains the first collection rate V2a, so that due to the difference in the portion in close contact with the pressure roller 520, a curve S may be generated at a portion of the upper transfer film 400b to have an increased conveying rate.

[0095] The first speed adjustment S152 may be an operation of controlling the first speed and the second speed to be the same as the linear speed of the pressing roller adjusted in the first curvature radius adjustment S151 after the first curvature radius adjustment S151.

[0096] That is to say, Figure 6As shown in (c), by increasing the conveying rate of the target substrate 200 to a second conveying rate V1b greater than the first conveying rate V1a, the conveying rate of the target substrate 200 can be controlled to have the same magnitude as the second linear velocity V1b of the pressing roller 520, and at the same time, by increasing the collecting rate of the transfer film 400 to a second collecting rate V2b greater than the first collecting rate V2a, the collecting rate of the transfer film 400 can be controlled to have the same magnitude as the second linear velocity VLb of the pressing roller 520. Therefore, the upper transfer film 400b can be collected while closely maintaining the curve, and the second curvature radius R2 of the curved arc 410 can be uniformly maintained.

[0097] In the case where the radius of curvature of the curved arc 410 is controlled to increase, the aforementioned process may be reversely applied.

[0098] Next, refer to Figure 5 and Figure 7 The method for transferring a micro device may further include a second control S160, wherein the curvature radius of the curved arc is adjusted by adjusting the conveying rate of the target substrate, and the second control S160 may include a second curvature radius adjustment S161 and a second rate adjustment S162.

[0099] Here, the second curvature radius adjustment S161 may be an operation in which the first speed of the target substrate is increased within a predetermined time, and the position of the first center of the curved arc is moved in the front direction based on the first direction A1 to control the curvature radius of the curved arc to increase, or the second curvature radius adjustment S161 may be an operation in which the first speed of the target substrate is reduced within a predetermined time, and the position of the first center of the curved arc is moved in the rear direction based on the first direction A1 to control the curvature radius of the curved arc to decrease.

[0100] That is to say, Figure 7 As shown in (a), when the target substrate 200 is conveyed at a first conveying rate V1a, the pressure roller 520 rotates at a first linear velocity VLa, and the transfer film 400 is supplied at a first supply rate VSa and collected at a first collection rate V2a, the curved arc 410 may have a first curvature radius R1.

[0101] In addition, if Figure 7As shown in (b), when the conveying rate of the target substrate 200 is reduced to a third conveying rate V1c that is less than the first conveying rate V1a, the transfer film 400 to which the micro device 300 temporarily attached to the target substrate 200 is attached may also be supplied at a third supply rate VSc that is less than the first supply rate VSa. Therefore, the first collection rate V2a of the transfer film 400 is greater than the third supply rate VSc, so that when the transfer film 400 is collected relatively quickly, the position of the first center C1 of the curved arc 410 may be moved in the rear direction based on the first direction A1 as the conveying direction of the target substrate 200, and the curved arc 410 may have a second curvature radius R2 that is less than the first curvature radius R1. Here, reducing the conveying rate of the target substrate 200 to the third conveying rate V1c may be performed within a predetermined time.

[0102] The second velocity adjustment S162 may be an operation of controlling the linear speed and the second velocity of the pressing roller to be the same as the first velocity of the target substrate adjusted in the second curvature radius adjustment S161 after the second curvature radius adjustment S161.

[0103] That is to say, Figure 7 As shown in (c), by reducing the linear velocity of the pressure roller 520 to a third linear velocity VLc that is less than the first linear velocity VLa, and reducing the collection rate of the transfer film 400 to a third collection rate V2c (i.e., less than the first collection rate V2a), the linear velocity of the pressure roller 520 and the collection speed of the transfer film 400 can be controlled to have the same magnitude as the third conveying rate V1c of the target substrate 200, and therefore, the second curvature radius R2 of the curved arc 410 can be uniformly maintained.

[0104] In the case where the radius of curvature of the curved arc 410 is controlled to increase, the aforementioned process may be reversely applied.

[0105] The first control S150 or the second control S160 may be performed when the curvature radius of the curved arc needs to be adjusted, for example, an initial setting operation at the beginning of the micro device transfer process.

[0106] Figure 8 1 is a diagram showing an example of a transfer process of a method for transferring a micro device according to a second exemplary embodiment of the present invention. In this exemplary embodiment, the position of the collecting roller may be different, and the other configurations are the same as those of the first exemplary embodiment, so repeated contents will be omitted where feasible.

[0107] like Figure 8As shown, the collecting roller 530a may be disposed at the front side of the first direction A1, which is the conveying direction of the target substrate 200 based on the pressure roller 520. The transfer film separated from the micro device 300 and bent upward to form the curved arc 410 may move so as to be in close contact with the pressure roller 520, move upward, and then be collected. Therefore, the supplied lower transfer film 400a and the collected upper transfer film 400b may be conveyed in the same direction (i.e., the first direction A1).

[0108] Fig. 9 1 is a diagram showing an example of an enlarged main part of a transfer process of a method for transferring a micro device according to a third exemplary embodiment of the present invention. In this exemplary embodiment, a pressurizing rod 600 may be further included, and other configurations are the same as those of the first exemplary embodiment, so that repeated contents are omitted where feasible.

[0109] like Fig. 9 As shown, the pressure rod 600 can be prepared at the inner side of the curved arc 410 formed by the transfer film 400. Here, the inner side of the curved arc 410 means the space in the direction of the first center C1. According to an exemplary embodiment, the pressure rod 600 can have a circular cross section and be formed by a flexible material. Therefore, when the upper transfer film 400b is pressurized by the pressure roller 520, the additional pressure F of the pressure rod 600 can be better transmitted, and the pressure is transmitted to the lower transfer film 400a along the lower direction. In order to effectively transmit the additional pressure F, the pressure rod 600 can be arranged so as to contact the inner surface of the curved arc 410, and can be arranged to be coaxial with the first center C1 of the curved arc 410. In this exemplary embodiment, when the rigidity of the transfer film 400 alone cannot generate enough pressure to transfer the micro device 300a to the target substrate 200, the additional pressure can be increased by the pressure rod 600 to provide enough pressure required for the transfer.

[0110] Fig.10 is a diagram showing an example of an enlarged main part of a transfer process of a method of transferring a micro device according to a fourth exemplary embodiment of the present invention.

[0111] like Fig.10 As shown, the lower transfer film 400a before the curved arc 410 is formed may contact the upper transfer film 400b after the curved arc 410 is formed. That is, according to the present exemplary embodiment, the pressing force of the pressing roller 520 may be directly transmitted to the lower transfer film 400a and the upper transfer film 400b.

[0112] In this case, in order for the upper transfer film 400b and the lower transfer film 400a that are in contact with each other to be smoothly conveyed, the transfer film 400 may further include a lubricating layer 403. The lubricating layer 403 may be provided on a side opposite to the adhesive layer 402 based on the base layer 401, and may be formed of a material having a very small friction coefficient. In this exemplary embodiment, when the rigidity of the transfer film 400 alone cannot generate a pressure sufficient to transfer the micro device 300a to the target substrate 200, the pressure applied by the pressure roller 520 may be directly applied to the micro device 300a to provide sufficient pressure required for the transfer. At the same time, although in Fig.10 Although not shown in the figure, in the present exemplary embodiment, the pressurizing rod 600 of the third exemplary embodiment may be additionally provided.

[0113] The description of the present invention is for illustration, and it will be understood by those skilled in the art that various changes in specific form and details may be made therein without changing the technical spirit or essential features of the present invention. Therefore, it should be understood that the above exemplary embodiments are illustrative in all respects and not restrictive. For example, each component element described in singular form may be allocated and provided, and similarly, the component elements described as being allocated may be provided in combination.

[0114] The scope of the present invention is expressed by the claims, and it should be understood that all changes or modifications derived from the meaning and scope of the claims and their equivalent concepts are included in the scope of the present invention.

[0115] <symbol description>

[0116] 200: target substrate 300, 300a: micro device

[0117] 400: transfer film 400a: lower transfer film

[0118] 400b: upper transfer film 410: curved arc

[0119] 520: pressure roller 530, 530a: collecting roller

[0120] 600: Pressure rod V1: First rate

[0121] V2: Second rate VL: Linear speed

[0122] VS: Supply rate.

Claims

1. A method for transferring a micro device, the method comprising: conveying the target substrate along a first direction at a first rate; supplying a transfer film bonded to a micro device in the first direction, the micro device facing an upper portion of the target substrate; Pressurizing the transfer film, the pressurizing comprising bending the transfer film separated from the micro device upward to form a curved arc, and pressurizing the upper transfer film conveyed after forming the curved arc with a pressurizing roller rotating on the upper side of the target substrate to transfer pressure to the lower transfer film combined with the micro device; and collecting the upper transfer film by conveying the upper transfer film conveyed after forming the curved arc in a second direction opposite to the first direction at a second rate, Wherein, based on the first direction, a first center of the curved arc is in front of a second center of the pressure roller.

2. The method according to claim 1, wherein: The linear speed of the pressure roller, the second speed, and the first speed are the same.

3. The method according to claim 1, further comprising: The first control is used to adjust the curvature radius of the curved arc by adjusting the linear speed of the pressure roller within a predetermined time.

4. The method according to claim 3, wherein: The first control includes a first curvature radius adjustment, in which the curvature radius of the curved arc is controlled to decrease by increasing the linear speed of the pressure roller and moving the position of the first center of the curved arc to the rear side based on the first direction, or the curvature radius of the curved arc is controlled to increase by reducing the linear speed of the pressure roller and moving the position of the first center of the curved arc to the front side based on the first direction.

5. The method according to claim 4, wherein: The first control further includes a first speed adjustment after the first curvature radius adjustment, in which the first speed and the second speed are controlled to be the same as a linear speed of the pressing roller adjusted in the first curvature radius adjustment.

6. The method according to claim 1, further comprising: The second control is used to adjust the curvature radius of the curved arc by adjusting a first velocity of the target substrate within a predetermined time.

7. The method according to claim 6, wherein: The second control includes a second curvature radius adjustment, in which the curvature radius of the curved arc is controlled to increase by increasing the first speed of the target substrate and moving the position of the first center of the curved arc to the front side based on the first direction, or the curvature radius of the curved arc is controlled to decrease by decreasing the first speed of the target substrate and moving the position of the first center of the curved arc to the rear side based on the first direction.

8. The method according to claim 7, wherein: The second control further includes a second velocity adjustment after the second curvature radius adjustment, in which the linear speed of the pressing roller and the second velocity are controlled to be equal to the first velocity of the target substrate adjusted in the second curvature radius adjustment.

9. The method according to claim 1, wherein: Pressurizing the upper transfer film includes transmitting additional pressure to the lower transfer film through a pressurizing rod disposed within the curved arc formed by the transfer film.

10. The method of claim 1, wherein: When the upper transfer film is pressurized, when the pressurizing roller presses the upper transfer film, the upper transfer film is in contact with the lower transfer film.

11. A device for transferring a micro device, the device comprising: a supply roller configured to supply the transfer film combined with the micro device in a first direction; a target substrate to which the micro-device is transferred from the supplied transfer film when the target substrate is conveyed in the first direction; a pressure roller disposed on an upper portion of the target substrate and configured to pressurize the transfer film separated from the micro device; and a collecting roller configured to collect the transfer film, wherein the transfer film for transferring the micro-device to the target substrate moves in a second direction opposite to the first direction while bending upward to form a curved arc, and The center of the pressing roller is arranged at a rear side of a center of the curved arc, and the pressing roller presses the transfer film moving in the second direction in a lower direction while forming the curved arc.

12. The apparatus according to claim 11, further comprising: A pressure rod is disposed within the curved arc formed by the transfer film.

13. The device according to claim 11, wherein: The transfer film comprises: a base layer having rigidity; and an adhesive layer disposed on one surface of the base layer to provide adhesion to the micro device, and The adhesive layer separated from the micro device contacts the pressure roller to provide friction.

14. The device according to claim 13, wherein: The transfer film further includes a lubricating layer provided on the other surface of the base layer so that the transfer films before and after the curved arc is formed contact with each other and are moved.

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