Lifting method, retransfer method and display manufacturing method

Abstract

To provide a scanning type reduction projection optical system capable of scanning a small irradiation area with a uniform and stable energy distribution over a wide area with high precision and at high speed while compensating for the lack of precision of a scanner without using a large-diameter, expensive fθ lens or telecentric reduction projection lens, and a lift device for mounting or retransfer equipped with the same at low cost, as well as a method for implementing the same. [Solution] A scanning-type reduced projection optical system that images a transverse multi-mode pulsed laser beam at the size of a micro-area on a donor substrate via a lens array zoom homogenizer, an array mask 10, a scanning mirror 4, a photomask 6, and a telecentric projection lens 8 lifts a micro-element on a donor substrate onto an opposing receptor substrate with high positional accuracy. The implementation process involves inspection to obtain positional information, division of the lift area, selection of the irradiation position, transfer, and stage movement.

Description

[Technical Field]

[0001] The present invention relates to a scanning reduction projection optical system and a laser processing device using the same. [Background technology]

[0002] One technology used in the manufacturing process of displays, etc., is to transfer microelements such as microLEDs arranged in a matrix on a donor substrate to a receptor substrate. There are also techniques for transferring various functional films, material films, organic EL films, etc., coated on the donor substrate to the receptor substrate. There are various techniques, such as LIFT (Laser Induced Forward Transfer), stamping, and roll transfer. However, it is not easy to achieve both the high-speed processing and high positional accuracy required for each process with any of these techniques, and even at high speeds, problems such as missing transfers and misalignment can occur. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2020-4478 [Patent Document 2] Japanese Patent Application Laid-Open No. 2006-41500 Summary of the Invention [Problem to be solved by the invention]

[0004] Therefore, the applicant developed a high-speed, high-precision lifting device (Patent Document 1). However, the micro-elements, etc. on the donor substrate or receptor substrate that are transferred and mounted by the transfer device using the stamp technology or roll transfer technology used in the lifting device can have defects of up to 1%. Therefore, there is a demand for both high precision and high speed in the technology for re-transferring micro-elements, etc. to these defective areas, and in the device using such technology.

[0005] Furthermore, such a technique can be used not only for retransfer from a donor substrate to a receptor substrate, but also for removing irradiated objects such as defective microelements or unnecessary material portions located on a substrate, and is expected to be used in defect removal processes as well as in mounting processes involving the transfer of microelements, etc.

[0006] On the other hand, unlike Patent Document 1, there is a high-precision transfer technology using a step-and-repeat method. For example, in a technology for retransferring microelements to non-element areas on a substrate to be repaired after defective microelements have been removed in advance, excimer laser light is shaped into laser light with a uniform energy distribution using a beam homogenizer composed of a lens array, and this is reduced and projected onto microelements located on a donor substrate (for retransfer) using a photomask and a reduction projection lens, and the microelements are lifted onto the substrate to be repaired. This technology can accurately lift (retransfer) microelements from the donor substrate onto the substrate to be repaired using a stage with high positional accuracy, but since the processing time required for each microelement is approximately 1 to 2 seconds, it is not practical in terms of production efficiency as a retransfer device used in the manufacturing process of displays, etc., where a large number of defective areas (up to 1%) may occur.

[0007] As a technology that enables higher speeds, a well-known technique is to use an optical system that combines a galvanometer scanner and an fθ lens to scan a laser beam at high speed and irradiate the object to be irradiated. While this technique can remove defective microelements and the like from the substrate to be repaired at high speed as long as the positional accuracy of the scanner allows, the subsequent re-transfer, which requires high positional accuracy, is difficult due to the accuracy limits.

[0008] Therefore, to solve the problem of positional accuracy caused by the scanner, it is possible to construct a scanning-type reduction projection optical system with high speed and high positional accuracy that reduces the dependency on the scanning accuracy of the scanner by selectively irradiating the scanned laser light onto openings arranged on a photomask via an fθ lens or the like and reducing and projecting this onto a predetermined irradiation target located on a substrate. Patent Document 2 shows an example of an optical system that compensates for positional deviation of the irradiation area on a donor substrate caused by low scanning accuracy by scanning the beam of an Nd:YAG laser with a galvanometer mirror and reducing and projecting it via an fθ lens and a photomask.

[0009] However, to increase the size of each substrate and achieve faster processing speeds, it is necessary to enlarge the irradiation area on the donor substrate and reduce the projection of the scanned laser light onto many irradiation targets in a short time. In other words, it is necessary to enlarge the scannable irradiation area on the photomask. In this case, the apertures of the fθ lens and reduction projection lens used in Patent Document 2 must be increased, and a telecentric design would be expensive.

[0010] Furthermore, in order to accommodate the miniaturization and high density of irradiation targets such as microelements, it is necessary to compensate for the accuracy limits of the scanner and to provide laser light with a stable and uniform intensity distribution on the donor substrate, with an extremely small irradiation area size so as not to interfere with adjacent irradiation targets. In addition, it is expected that lift devices, retransfer devices, and defect removal devices equipped with such optical systems will be realized to replace the device described in Patent Document 1.

[0011] Therefore, the present invention aims to provide a scanning type reduction projection optical system that can scan a small irradiation area with a uniform and stable energy distribution over a wide area with high precision and at high speed while compensating for the lack of precision of the scanner without using a large-diameter, expensive fθ lens or telecentric reduction projection lens, and a low-cost lift device or the like for mounting or retransfer that is equipped with this system, and further to provide a method for implementing these using these. [Means for solving the problem]

[0012] The first invention is a scanning-type reduction projection optical system that can be used in a laser processing device that irradiates a multi-mode pulsed laser beam onto an irradiation target, such as a microelement such as a mini-LED or micro-LED arranged in multiple rows on a substrate, or a material film or functional film attached to the substrate by coating or printing, to induce a reaction either directly on the irradiation target or via a substance between the substrate and the irradiation target.The optical elements of the scanning-type reduction projection optical system include a lens array-type zoom homogenizer, a scanning mirror scanned by a drive axis control device on one or more axes, a photomask, and a projection lens system that is telecentric at least on the image side, and the photomask has multiple openings of a predetermined shape that are reduced and projected, arranged at a predetermined pitch.

[0013] Furthermore, this homogenizer is a zoom homogenizer that includes a first lens array, a second lens array, and a condenser lens, and the second lens array and the condenser lens form an infinity-corrected optical system, and images an irradiation area of ​​a predetermined size that covers one or more adjacent groups of apertures on the photomask onto the photomask, and particularly compensates for variations in the position and size of the irradiation area and the energy intensity distribution within the irradiation area.

[0014] "Compensating for fluctuations" refers to the state in which fluctuations in the oscillation state, for example, are known to cause fluctuations in the beam pointing stability, beam size, and even intensity distribution of the beam cross section of the laser beam, but this zoom homogenizer avoids the effects of these fluctuations within the irradiation area imaged on the photomask. As a result, an image of a micro-area with an extremely uniform energy distribution can be obtained on the donor substrate projected onto the mask.

[0015] The predetermined size is a size such that the irradiation area does not extend to any of the adjacent openings around the group of openings. In other words, taking into account the accuracy of the irradiation position on the photomask due to the scanning accuracy of the scanning mirror, the size is such that if laser light were to pass through the adjacent opening and irradiate an object (not intended for irradiation) on the substrate, the boundary (outer edge) of the energy distribution above the threshold at which a reaction would be induced would not extend to any of the adjacent openings in the group of openings contained within the irradiation area. For example, in FIG. 1, the irradiation area (DP) surrounded by a dashed line illustrates the maximum allowable size of the irradiation area covering a group of four openings (61), while the small irradiation area surrounded by a dotted line illustrates the minimum size of the irradiation area covering a single opening. In the figure, each example of the irradiation area is doubled to represent deviations due to the positional accuracy of the scanner.

[0016] For example, when openings (squares) are arranged in a matrix on the photomask (6) as shown in FIG. 1, the side (DP) of a predetermined size of the irradiation area (square) in which n×n (n≧1) of the openings are irradiated at once falls within the range of the following formula, where Ma is the side of each opening, Pi is the pitch, and St is the scanning position accuracy on the photomask by the scanner. Pi×(n-1)+Ma+St ≦ DP < Pi×(n+1)-Ma-St If the specified size exceeds this range, laser light with energy exceeding the threshold that passes through (part of) an unintended adjacent aperture may be reduced and projected onto an unintended target object, potentially inducing a reaction. If the aperture shape is not square, or if n x m apertures are irradiated simultaneously, the range of the specified size (DP) is a design matter.

[0017] When a photomask with openings arranged in a matrix is ​​used for simultaneous irradiation, the pitch (Pi) of the openings on the photomask is fixed at c times the pitch of the objects to be irradiated that are to be lifted onto the receptor substrate, assuming that the reduction magnification of the reduction projection lens is 1 / c.

[0018] Depending on the specifications of the reduction projection lens, various designs can be selected for the number of apertures, from a single row arrangement as shown in Figure 2 to a matrix arrangement as shown in Figure 1. These also depend on the scannable range of the scanning mirror.

[0019] The lens elements constituting the first and second lens arrays are not limited to fly-eye types, but may be cylindrical or spherical. Therefore, each lens array may be composed of a combination of orthogonal lens elements. Furthermore, there may be a zoom homogenizer in which a third lens array is added.

[0020] The second invention is a scanning type reduction projection optical system according to the first invention, wherein the projection lens system includes a field lens arranged between the condenser lens and the photomask, and a reduction projection lens that is telecentric at least on the image side.

[0021] The specifications of the field lens are determined based on the specifications of the zoom homogenizer, the condenser lens (3), and the telecentric lens, and in the present invention, its preferred position is immediately before the photomask (6) as shown in Figure 3. The focal length of this field lens (5) is designed with a curvature that allows the laser light from the zoom homogenizer (with a number of focal points corresponding to the number of lens elements in the second lens array (2)) to pass through the diaphragm (7) placed at the entrance pupil position of the image-side telecentric reduction projection lens (8).

[0022] The third invention is a scanning reduction projection optical system in which the scanning mirror (4) in the first or second invention is configured with a two-axis galvanometer scanner. This makes it possible to scan the irradiation area of ​​the laser light toward the openings arranged in multiple rows on the photomask (6). The control device for the scanning mirror can be various, such as a dedicated controller or a combination of a dedicated board and a PC. Either can also be used to control the oscillation timing of the pulsed laser light.

[0023] The fourth invention is a scanning reduction projection optical system according to any one of the first to third inventions, which uses a zoom homogenizer in which an array mask consisting of a group of apertures, each of which has a size smaller than the size of each lens element constituting the lens array and is arranged facing each lens element, is placed immediately before the first lens array or between the first lens array and the second lens array. This eliminates virtual images caused by stray light between lens elements on a donor substrate onto which the aperture shape on the photomask is reduced and projected, and produces an extremely small image with a stable and highly uniform energy distribution. Furthermore, it produces a small image of any shape that matches the aperture shape of the photomask or its configuration, regardless of the lens element shape.

[0024] If the lens elements are cylindrical, they may be combined with an array mask with elongated apertures. The position of the array mask is a design factor determined by checking the irradiation area on the photomask with a beam profiler or the like, in the range immediately before or after the first lens array, or between the first and second lens arrays. The number of lens elements and the number of aperture groups on the array mask do not have to match. For example, the NA of the optical system can be adjusted by reducing the numerical aperture at the outer periphery of the array mask.

[0025] As an example of the predetermined size, let dA be the element size of a fly-eye type first lens array or the size of the opening of the array mask arranged immediately before the first lens array, f1 be the focal length of the first lens array, f2 be the focal length of the second lens array, and a be the distance between these first and second lens arrays (here a = f2). Also, let fC be the focal length of the condenser lens, fF be the focal length of the field lens that makes up the projection lens system, and b be the distance between these lenses. Then, the predetermined size (DP) of the irradiation area imaged on the photomask can be expressed by the following equation:

[0026]

number

[0027] However, this configuration is not ideal due to the effects of aberrations in the first lens array and diffraction caused by the array mask. Therefore, these problems can be avoided by moving the first lens array toward the light source and placing the array mask near the light source-side focal position of the second lens array. Furthermore, the utilization efficiency of the pulsed laser light extracted by the array mask can be improved.

[0028] The fifth invention is a scanning reduction projection optical system in which the array mask in the fourth invention has multiple types of aperture groups arranged within the surface of its substrate, allowing aperture groups of different sizes, shapes, or numbers of apertures to be switched and used.

[0029] If the number of apertures in the array mask is less than the number of lens elements in the first lens array, the array mask will have the function of anomaly illumination. Figure 4 shows an example of an array mask in which a group of apertures for anomaly illumination and a group of opposing apertures, the same number as the lens elements in the lens array, are arranged on a single substrate.

[0030] The sixth invention is a scanning reduction projection optical system according to the fourth or fifth invention, in which the array mask is mounted on a mount including a θ axis that allows for minute rotational adjustment around the optical axis.

[0031] A highly uniform image is obtained by overlapping the light emitted from each lens element of the second lens array on the photomask by a condenser lens. Here, in terms of the relative positional relationship between the array mask and the second lens array, misalignment in the plane perpendicular to the optical axis does not affect uniformity. However, if there is a misalignment in the rotational direction (θ) around the optical axis, the contours of the image will become blurred, resulting in multiple images. This is shown in Figure 5 (an array mask with a circular aperture shape is used here). The effect of such misalignment in the rotational direction becomes greater as the image becomes smaller.

[0032] A seventh aspect of the present invention is a scanning reduction projection optical system in which the various optical elements in any one of the first to sixth aspects of the present invention correspond to the oscillation wavelength of an excimer laser.

[0033] An eighth invention is a laser processing apparatus that irradiates a multi-mode pulsed laser beam toward an irradiation target located on a substrate to induce a reaction, and that is configured to reduce and project the multi-mode pulsed laser beam emitted from the laser apparatus onto the substrate held on a stage having at least X-axis and Y-axis drive axes using a scanning reduction projection optical system according to any one of the first to sixth inventions.

[0034] Here, the irradiation target located on the substrate may be various, such as the aforementioned defective microelement, unnecessary portions of the functional film on the circuit board, etc. The induced "reaction" here includes, but is not limited to, mechanical, optical, electrical, magnetic, and thermal reactions.

[0035] The ninth invention is a laser processing device for mounting or retransfer, or for both, in the eighth invention, in which the substrate is a donor substrate on whose surface the irradiation object is located, and pulsed laser light is irradiated toward the irradiation object from the back surface of the donor substrate to selectively peel or separate the irradiation object and lift it onto a receptor substrate opposite the donor substrate, and more specifically, it is a lifting device.

[0036] The stage is a donor stage that holds the donor substrate with its back surface facing the incident side of the pulsed laser light, and further has a receptor stage that holds the receptor substrate and has an X-axis, a Y-axis, a vertical Z-axis, and a θ-axis that rotates within the XY plane, the scanning reduction projection optical system and the donor stage are placed on a first base plate, and the receptor stage is placed on a second base plate or a base plate, and the first base plate and the second base plate are each placed independently on the base plate.

[0037] Here, selectively peeling or separating the irradiated object means, when the irradiated object is a microelement, selectively peeling the microelement itself from the donor substrate, and when the irradiated object is a functional film or the like printed or coated on the donor substrate, selectively peeling or separating the functional film or the like in a portion corresponding to the imaging position and size of the laser light projected in a reduced size through the opening on the photomask. Note that this peeling or separation also includes cases where the so-called ablation process is not involved.

[0038] Furthermore, because both stages perform step-and-repeat operations, i.e., both stages are stationary when the laser light is irradiated, the rolling guide method, which has physical contact with the guide and is stable, is more preferable than the air bearing method, also in terms of cost.

[0039] On the other hand, the first surface plate, second surface plate, and base surface plate on which these stages are installed must all be made of highly rigid materials such as steel, stone, or ceramic material. The preferred stone material is granite.

[0040] With the above configuration, the positional accuracy and stability of the irradiation object lifted onto the receptor substrate are determined by the relative positional relationship between the mask, reduction projection lens, and donor substrate, whose fluctuations are suppressed by the scanning type reduction projection optical system and the vibration-free installation structure of the stages for each substrate, as well as the arrangement positional accuracy of the irradiation object on the donor substrate.

[0041] A tenth invention is a lift device according to the ninth invention, wherein the control device of the scanning mirror includes a function of controlling the scanning mirror that scans the optical axis of the pulsed laser toward an opening on a photomask selected based on previously acquired positional information of the object to be irradiated on the donor substrate and information on the planned lift position on the receptor substrate, and a function of controlling the irradiation of the pulsed laser light.

[0042] In particular, when the lift device is used as a retransfer device, the possibility cannot be denied that there are areas without elements or defective areas where defective elements are mounted on the donor substrate for retransfer. Therefore, in order to irradiate the laser light from the scanning reduction projection optical system only to the irradiation target on the donor substrate to be lifted, which is selected based on the information on the defective areas on the receptor substrate to be lifted and the donor substrate from which the lift is made, the scanning mirror is controlled so that the optical axis scans the opening on the photomask facing the selected irradiation target.

[0043] An eleventh invention is a lift device according to the ninth or tenth invention, wherein the donor stage can hold two or more donor substrates and can be switched between them for use.

[0044] For example, a first donor substrate coated with a conductive paste film is irradiated with a pulsed laser beam of a predetermined size, which is reduced and projected by the scanning reduction projection optical system according to the present invention, and a conductive paste film of a portion corresponding to the reduced size is lifted (paste printed) to a position on the opposing receptor substrate. Next, the donor stage is moved to switch the first donor substrate with a second donor substrate (carrier substrate), and the microelement (device) on the carrier substrate is lifted to the same position on the receptor substrate and fixed via the conductive paste film.

[0045] A twelfth aspect of the present invention is a lift device according to any one of the ninth to eleventh aspects of the present invention, wherein the donor stage is suspended from the underside of the first base plate.

[0046] The order in which the axes constituting the donor stage are installed is a matter of design, but preferably they are suspended from the bottom surface of the horizontally installed first base in the order of X-axis and Y-axis, and if a θ-axis is included, they are installed below that. The axis configuration of the receptor stage is also a matter of design.

[0047] A thirteenth invention is the laser processing device according to the eighth invention or the lift device according to any one of the ninth to twelfth inventions, characterized in that the laser device is an excimer laser device.

[0048] The fourteenth aspect of the present invention is a lifting method for mounting or retransferring an irradiation object on a donor substrate onto an opposing receptor substrate using a lifting device according to the present invention equipped with a scanning type reduction projection optical system according to any one of the ninth to thirteenth aspects of the present invention, the method comprising an inspection step of acquiring in advance "position information D" which is position information of the irradiation object on the donor substrate and "position information R" which is a planned lift position of the irradiation object onto the receptor substrate, a division step of dividing an area on the donor substrate into "divided areas D" of a predetermined size, and a selection step of selecting a position of the irradiation object within the divided area D to be lifted based on the position information D and the position information R. This lifting method includes a transfer step in which the selected irradiation object in divided area D is lifted toward "divided area R," which is defined as the area on the receptor substrate facing the divided area D for convenience, by using laser light that passes through an opening on a photomask that faces the position of the selected irradiation object (via a reduction projection lens) and is irradiated onto the donor substrate; and a movement step in which the donor substrate and receptor substrate are moved to the next lift area after the transfer step. Thereafter, the transfer step and the movement step are repeated, and the selected irradiation object on the donor substrate is mounted or re-transferred onto the receptor substrate, covering the entire area of ​​the receptor substrate that is to be lifted.

[0049] In the inspection process, there are various methods for obtaining position information for the mounted irradiation target. This is a design issue, but it can also be the individual center of gravity coordinates obtained by processing images of all or two or more individual irradiation targets by sampling. Determining the origin of these coordinates is also a design issue. Position information D and / or position information R can be obtained using an inspection device separate from the lifting device, and the results can be transmitted to the control device of the lifting device via communication means. Alternatively, they can be calculated from design values ​​based on the measurement results obtained during alignment of the donor substrate and receptor substrate by the lifting device. It is desirable to perform this inspection process before the division process, although this depends on the total takt time for mounting or retransfer.

[0050] The position of the selected irradiation object within the divided area D is the position of all irradiation objects (excluding defective areas) on the donor substrate that face the intended lift position within the opposing divided area R when this lift method is used for implementation, and is the position of the irradiation object (excluding defective areas (non-element areas)) on the donor substrate that faces the defective areas (non-element areas) on the receptor substrate when used for retransfer.

[0051] The transfer process includes both a case where the scanning of the scanning mirror is not stopped and the pulsed laser light is oscillated in synchronization with the time when the optical axis is scanned over the position of the selected irradiation object, and a case where scanning and stopping are repeated.

[0052] Furthermore, the position information D can include not only the position coordinates of the microelement as the irradiation object normally mounted on the donor substrate or the irradiation object that can be normally peeled or separated, but also the position coordinates of the irradiation object that is identified as defective or missing (as abnormal position information). The same applies to the position information R when this lifting method is used for re-transfer.

[0053] The maximum size of the division area D depends on the reduction projection lens that constitutes the scanning reduction projection optical system installed in this lifting device. In particular, the numerical aperture and magnification of a telecentric reduction projection lens are limited in consideration of its manufacturing cost, and these specifications limit the area on the photomask, and therefore on the donor substrate, that can be lifted in one scan.

[0054] In this lifting method, regardless of whether the lifting device is used for mounting or for retransfer, the above-mentioned divided area D is set in the area of ​​the donor substrate, and the donor substrate and receptor substrate are moved by the step-and-repeat operation of each stage holding them, and vibration is avoided when these stages stop, allowing for accurate lifting.

[0055] The 15th invention is a lifting method in the 14th invention, in which the design mounting pitch of the irradiated object on the donor substrate is 1 / 2 times, 1 / 3 times, etc., an integer greater than or equal to 1, of the design mounting pitch calculated from the position information R when the lifting method is used for mounting, or of the design mounting pitch for the irradiated object on the receptor substrate that has already been mounted when the lifting method is used for retransfer.

[0056] In addition, when the planned lift positions on the receptor substrate are arranged in an X x Y matrix, this also includes the case where the mounting pitch on the opposing donor substrate of the same size is 1 / n times in the X column and 1 / m times in the Y column (n and m are different integers greater than or equal to 1).

[0057] In the sixteenth invention, first, it is assumed that there is an error between the substrates (taking into account the difference in the mounting density on the donor substrate) between the actual mounting pitch of the irradiation object on the donor substrate calculated from the position information D acquired in the inspection process and the mounting pitch on the receptor substrate calculated from the position information R. When this lifting method is used for mounting, this mounting pitch on the receptor substrate is calculated from the planned lift position (design position) of the irradiation object, and when used for re-transfer, it is the actual mounting pitch of the irradiation object that has already been mounted.

[0058] In light of the donor substrate manufacturing process, even if there are no defective elements or no-element areas on the donor substrate, the actual mounting pitch of the mounted irradiation objects may have an error (δPi) from the designed mounting pitch. Even if this error does not tend to vary depending on the location on the same substrate, it is possible that there may be differences (errors) between donor substrate manufacturing lots and even between donor substrates. In this case, the error δPi accumulates according to the number of irradiation objects contained in the divided area D.

[0059] Therefore, the sixteenth aspect of the present invention is a lifting method in which the movement amount of each substrate in the movement step of the fifteenth aspect of the present invention is set to a movement amount that offsets this "accumulated error amount."

[0060] In the sixteenth invention, when an irradiation object in a divided area D is lifted using a donor substrate with an error (ΔPi) of a certain magnitude or more, depending on the positions of the irradiation objects in that area (the number of irradiation objects from a reference position), the cumulative error there may exceed the allowable range in terms of lift position accuracy. In addition to the deviation between the intended lift position on the receptor substrate and the position of the irradiation object on the lifted donor substrate, the deviation between the intended position where the laser light passing through the opening in the photomask is imaged on the donor substrate and the position of the irradiation object to be irradiated by that light becomes a particular problem when the mounting density of the irradiation objects on the donor substrate is high and the pitch is narrow.

[0061] Therefore, in the 17th invention, the distance between adjacent irradiation objects on the donor substrate is set as the upper limit, and the range of the allowable cumulative error amount is determined taking into consideration the difference between the irradiation size of the laser light irradiated toward the irradiation object on the donor substrate and the size of the irradiation object, and the effect that these positional deviations have on the lift position accuracy.If the cumulative error amount within the divided area D exceeds this allowable range at the position where it is maximum (for example, the lower right end when the upper left end is used as the reference), the size of the divided area D in the division process of the 16th invention is further reduced to a size where the cumulative error amount at that position falls within the allowable range, resulting in a ``corrected divided area D.''

[0062] Then, the selected irradiation object in the correction division area D is mounted or retransferred into a "correction division area R" on the opposing receptor substrate, which is also set to the same size for convenience. After that, a movement step is performed in which the donor substrate and receptor substrate are moved by stages to lift them to the next correction division area R. At this time, the movement amount of each stage is adjusted so as to cancel out the accumulated error amount.

[0063] When determining the allowable range of this cumulative error amount, even if the cumulative error amount does not exceed the maximum value mentioned above within one divided area D, it is advisable to determine this allowable range (size of correction divided area D) assuming that the maximum value may be exceeded as a result of repeating movement processes according to the design pitch on the donor substrate (or on the receptor substrate) for the entire receptor substrate, or by simulating this in advance.

[0064] The 18th invention is a lifting method according to the 17th invention, in which the size of the repaired divided area D, the combination of the movement amounts of each stage, and the order of performing each step are determined by a simulation program using position information D, position information R, the size of the divided area D, and the tolerance range as parameters, so as to minimize the time required for mounting or retransferring over the entire receptor substrate. [Effects of the Invention]

[0065] A scanning reduction optical system is realized at low cost, which compensates for the lack of scanning accuracy of a scanning mirror without using a large-diameter fθ lens or telecentric projection lens, and scans a small and stable irradiation area with a uniform and unfluctuous energy distribution toward openings arranged on a photomask, and projects a highly uniform and highly accurate reduction onto the irradiation object, as well as a defect removal device equipped with this and a lift device for mounting or retransfer. [Brief explanation of the drawings]

[0066] [Figure 1] FIG. 1 is a conceptual diagram illustrating a photomask in which openings are arranged in a matrix. [Figure 2] 1 is a conceptual diagram illustrating a photomask in which openings are arranged in a row. [Figure 3] A conceptual diagram illustrating the arrangement of components in a scanning reduction projection optical system (without an array mask). [Figure 4] FIG. 10 is a schematic diagram illustrating an array mask in which a plurality of aperture groups are arranged. [Figure 5]Beam profiler image of the (θ-axis offset) irradiated area on the photomask. [Figure 6A] A schematic conceptual diagram (3D) of a lift device equipped with a scanning reduction projection optical system. [Figure 6B] 1 is a schematic conceptual diagram of a lift device equipped with a scanning reduction projection optical system. [Figure 7] Conceptual diagram of the element configuration of a zoom homogenizer. [Figure 8A] Conceptual diagram of an array mask. [Figure 8B] Photo of the array mask. [Figure 9] 1 is a conceptual diagram showing the arrangement of each optical element from the zoom homogenizer to the donor substrate. [Figure 10A] Beam profile image showing the imaging state on the photomask when a rectangular array mask is inserted. [Figure 10B] Beam profile image showing the imaging state on the photomask when a circular array mask is inserted. [Figure 11] FIG. 2 is a conceptual diagram of a photomask used in Example 1. [Figure 12] A reduced-scale image of the laser beam profile projected onto the donor substrate. [Figure 13] A conceptual diagram of an area where microelements are mounted over the entire effective area of ​​a donor substrate. [Figure 14] A conceptual diagram of how a 6-inch donor substrate is divided into 27 separate areas. [Figure 15] 1 is a conceptual diagram showing the relationship between the position on the donor substrate and the amount of accumulated error. [Figure 16] 10 is a conceptual diagram showing the overlap of defect position information D and defect position information R. FIG. [Figure 17] 10 is a conceptual diagram showing how opposing substrates are lifted up in their divided areas facing each other. [Figure 18] 10 is a conceptual diagram showing how each of the divided areas of the substrate, which do not face each other, is lifted up facing each other. DETAILED DESCRIPTION OF THE INVENTION

[0067] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The following describes embodiments of the present invention with reference to specific examples and drawings. For convenience, the following description may use the above-mentioned conceptual diagrams. [Example]

[0068] In this Example 1, we demonstrate an example of a lifting device that mounts 222 × 225 micro LED elements (micro LED elements) in a matrix on a 6-inch donor substrate, a total of 49,950 of which are micro LED elements, arranged without defects on the donor substrate. The required lift position accuracy for the approximately 50,000 micro LED elements mounted on the receptor substrate is ±2 μm, with a pitch of 450 μm in each axial direction. The micro LED elements are arranged on the donor substrate at a pitch half the pitch of the intended lift positions on the receptor substrate, without defects (no missing elements), for a total of approximately 200,000 micro LED elements. The distance (spacing) between adjacent micro LED elements is 195 μm in X and 165 μm in Y. In this example, for simplicity, the receptor substrate size is the same as the donor substrate size, and the array pitch of the microelements is the same on both the X and Y axes, but these are all design considerations.

[0069] First, an example of the appearance of a lift device according to an embodiment of the present invention is shown in Figure 6A. The configuration of this appearance diagram is capable of handling receptor substrates of 55 inches or larger. A conceptual diagram of the layout of the main components is shown in Figure 6B. Note that in Figure 6B, the laser device, various control devices, and mounts for other optical elements are omitted, and the X-axis, Y-axis, and Z-axis directions are shown within the drawing. The first surface plate (G11, G12) and the second surface plate (G2) are all stone surface plates made of granite. Furthermore, the base surface plate (G) is made of highly rigid iron.

[0070] It is also desirable to have a rotation adjustment mechanism between each surface plate and between each surface plate and each stage to finely adjust the installation angle (perpendicular / parallel). Specifically, the rotation adjustment mechanism described in Patent Document 1 mentioned above is suitable. Furthermore, it is desirable to install a high-magnification camera that monitors the position of each substrate in a location separate from the vibration system of the stage that holds the substrate.

[0071] The laser device used in Example 1 is an excimer laser with an oscillation wavelength of 248 [nm]. The spatial distribution of the emitted laser light is approximately 8 × 24 [mm], and the beam divergence angle is 1 × 3 [mrad]. All figures are expressed in (length × width), and the numerical values ​​are FWHM. Note that excimer lasers have various specifications, including differences in output, repetition frequency, beam size, and beam divergence angle, as well as some that emit vertically elongated laser light (with the vertical and horizontal directions reversed). However, there are many excimer lasers that can be used in this example by adding, omitting, or modifying the design of optical systems. Furthermore, depending on the size of the laser device, it may be installed on a base that is different from the base on which the stages of the lift device are generally installed.

[0072] The light emitted from the excimer laser enters the telescope optical system and propagates to the zoom homogenizer. Here, as shown in FIG. 6B, the zoom homogenizer is placed on the first base plate (G11) so that its optical axis is aligned with the X axis. The laser light just before entering the zoom homogenizer is adjusted by the telescope optical system to become roughly parallel light, and regardless of the position of the zoom homogenizer, it enters the zoom homogenizer along the X axis with roughly the same size. In this embodiment, the size is approximately 25 × 25 mm (Z × Y).

[0073] Each lens array (1, 2) constituting the zoom homogenizer in this embodiment is a pair of uniaxial cylindrical lens arrays combined at right angles in the YZ plane perpendicular to the optical axis, as shown in the conceptual diagram in Fig. 7. Laser light enters the first lens array (1) of the initial set, and while being condensed, passes through an array mask (10) placed near the light source side focal position of the second lens array (2) of the subsequent set, and then propagates through the second lens array (2) and the condenser lens (3) in that order. In this Example 1, an array mask with 0.75 mm square openings arranged in a matrix was used. A conceptual diagram of this is shown in Figure 8A. In this conceptual diagram, the positional relationship between the array mask (10) placed immediately before the fly-eye type lens array (1) and its openings (101) is shown in order to show how it corresponds to the lens array. The appearance of the array mask used in this Example is shown in Figure 8B.

[0074] A conceptual diagram of the arrangement of each optical element from the zoom homogenizer to the donor substrate is shown in Figure 9. The exact arrangement is a matter of design. The laser light emitted from the zoom homogenizer is scanned by a two-axis scanning mirror (4) and its control device, propagates to a field lens (5), and is imaged on a photomask (6).

[0075] The image plane on the photomask (6) is the image plane of an infinity correction optical system composed of the second lens array (2) and condenser lens (3), with the aperture (101) of the array mask (10) as the object plane. The laser light is scanned by the scanning mirror (4) and propagates toward a selected aperture (61) on the photomask (6), forming an image in an irradiation area of ​​a predetermined size. Figure 10A shows the beam profile image. This predetermined size is the boundary (outer periphery) of the energy distribution above the threshold that would induce a reaction if irradiated onto an unintended target through an unselected adjacent aperture on the photomask. In this example, it is approximately 1 mm (FWHM). Figure 10B shows the beam profile on the same photomask (6) when a circular aperture is used in the array mask (10).

[0076] The photomask (6) used in this Example 1 is a synthetic quartz plate with a pattern drawn (applied) by chrome plating. A conceptual diagram is shown in Figure 11. Laser light passes through the white window portion (61) that is not chrome plated and is blocked by the colored portion (62) that is chrome plated. The aperture size is 60 x 100 μm, and 74 apertures are arranged at a pitch of 600 μm in the X-axis direction and 25 apertures are arranged at the same pitch in the Y-axis direction, for a total of 1,850 apertures. The chrome-plated surface is the laser light emission side, while the laser light incidence side is coated with an anti-reflection film for 248 nm. Furthermore, aluminum deposition or a dielectric multilayer film can be used instead of chrome plating.

[0077] The photomask (6) and the array mask (10) are fixed to dedicated mounts (not shown), and these mounts have a total of six-axis adjustment mechanisms: the W-axis, U-axis, and V-axis, which move in the X-axis, Y-axis, and Z-axis directions, respectively; the R-axis (θ-axis), which is a rotation axis (around the optical axis) in the YZ plane; the TV-axis, which adjusts the tilt relative to the V-axis; and the TU-axis, which adjusts the tilt relative to the U-axis.

[0078] The laser light (optical axis) passing through the zoom homogenizer is scanned at high speed over the openings on the photomask by the scanning mirror (4), and the excimer laser device oscillates in pulses synchronized with the timing at which the optical axis is scanned over the position of each opening.

[0079] The laser light that passes through the photomask pattern propagates through an aperture (7) to an image-side telecentric projection lens (8) with a reduction magnification of 3 / 4, and is then projected onto the donor substrate (91) at a reduced size from its rear surface to its front surface (bottom surface) at a position where a microelement measuring 30 × 60 μm (X × Y) is mounted. Figure 12 shows a beam profile image of the projected laser light. The microelements on the donor substrate irradiated with the scanned laser light are lifted and mounted one after another in a matrix pattern on the opposing receptor substrate at a pitch of 450 μm.

[0080] The number of lifted 30×60 μm irradiation targets corresponds to the number of the 74×25 openings on the photomask, and the lift range is approximately 33×11 mm.

[0081] The reduction projection lens (8) is telecentric on the image side, and in addition to adjustment using a Z-axis driven stage that holds it, it is also possible to add a function for adjusting the Z-axis direction of the donor substrate (Z-axis stage (Zd)) to support imaging onto the light absorption layer. However, it is necessary to consider the decrease in lift position accuracy due to the increased load on the donor stage.

[0082] Furthermore, when adjusting the imaging position at the interface between the donor substrate surface and the light-absorbing layer, etc., a real-time monitor using a confocal beam profiler (BP) whose imaging plane is a plane that is conjugate to the mask surface and the reduction projection lens is effective. In this Example 1, the spatial intensity distribution of the laser light that is reduced and projected onto the interface between the donor substrate surface and the microelement is monitored in real time with high resolution.

[0083] A laser beam is scanned toward all apertures on the photomask (6), sequentially irradiating the microelements arranged on the donor substrate whose imaging position has been adjusted. This results in 1,850 microelements, corresponding to the number of apertures on the photomask, being mounted at the same number of planned lift positions on the receptor substrate. These 1,850 lift areas correspond to one area when the receptor substrate is divided into three areas (A-C) along the X axis and nine areas (1-9) along the Y axis, for a total of 27 areas (A1-A9, B1-B9, C1-C9). The size of each area is approximately 33 x 11 mm, determined by the scanning angle of the scanning mirror and the aperture diameter of the reduction projection lens. After lifting of this area is completed, the donor substrate and receptor substrate are moved to the next lift area. For example, the movement is 33.3 mm along the X axis and 11.25 mm along the Y axis. After that, lifting is performed again at 1,850 locations, and this process is repeated for all the planned lift locations, completing the mounting of 49,950 microelements from the donor substrate to the receptor substrate. As mentioned above, the microelements are mounted on the donor substrate without any defects at a high density of half the pitch of the planned lift locations on the receptor substrate, so one donor substrate can be used to mount elements on four receptor substrates.

[0084] Furthermore, depending on the relationship between the image size of each opening of the laser light on the donor substrate and its energy density, if the predetermined size (DP) of the laser light irradiation area on the photomask can be set to a size that allows four openings to be irradiated at once, for example, as shown by the dotted line in Figure 1, the time required for implementation can be reduced to approximately one-quarter.

[0085] Furthermore, as shown in Figure 13, when the donor substrate is in the shape of a wafer and has microelements mounted over its entire effective area, it is possible to set a lift area (the area indicated by diagonal lines in the figure) along the mounting area of ​​the microelements, and scan the scanning range of the scanning mirror to match this, thereby lifting the microelements located in every corner.

[0086] The above is a specific example of the lifting device and mounting method for mounting a microelement on a donor substrate onto an opposing receptor substrate. [Example]

[0087] In Example 2, assuming no transfer defects, a 6-inch receptor substrate (hereinafter simply referred to as the "receptor substrate" in this Example 2) is used to repair defective areas equivalent to approximately 1% of the target substrate. The substrate has 495 × 495 = 245,025 40-μm square microelements mounted in a matrix at a 200-μm pitch with adjacent elements. This example demonstrates repair using a repair lift device according to the present invention. Similar to the receptor substrate, the microelements used for retransfer (repair) on a 6-inch repair donor substrate (hereinafter simply referred to as the "donor substrate" in this Example 2) also have approximately 1% of non-element (and defective) areas. Note that the donor substrate in Example 2 has microelements arranged at a pitch of 50 μm, which is 1 / 4 the designed mounting pitch of the microelements mounted on the receptor substrate. The total number of microelements is over 3.9 million. Therefore, the spacing between adjacent microelements is 10 μm. In addition, the general configuration of the scanning reduction projection optical system mounted on the lift device of this embodiment 2 and the structure of the device are the same as those of embodiment 1, but the specifications of each optical element, their placement position, and the beam profile shape determined by these are design matters.

[0088] As shown in FIG. 1, the photomask (6) in this second embodiment has 200-μm square apertures (Ma), which are slightly larger than the shape determined by the magnification (1 / 4) of the reduction projection lens (8) and the microelement size (40 μm square), arranged in a 165 × 55 matrix with an 800-μm pitch (Pi). This arrangement corresponds to the arrangement of the microelements mounted on the receptor substrate. The size of the irradiation area imaged on this photomask by the scanning reduction projection optical system is approximately 1 mm square, the same as in the first embodiment, and is large enough to irradiate without interfering with adjacent apertures on the photomask. The laser light passing through this aperture is imaged via the image-side telecentric reduction projection lens (8) onto the microelements used for retransfer (repair) on the donor substrate (9).

[0089] Excimer laser light having the above-mentioned irradiation area size, pulsed in synchronization with the operation of the scanning mirror (4), is irradiated onto a 200 μm square aperture on a photomask (6). The laser light passing through this aperture passes through a 1 / 4x image-side telecentric projection lens (8) and is directed from the backside of the donor substrate toward the microelements arrayed thereon, spaced 10 μm apart without interfering with adjacent microelements. In this example, the irradiated pulsed laser light forms an image on the front (bottom) surface of the donor substrate at a 50 μm square, slightly larger than the microelement size, inducing a reaction and lifting the microelement at that position toward an element-free area on the receptor substrate.

[0090] Below, the specific lifting method for retransfer (correction) will be explained for each step. (1) Inspection process The position information of the microelements mounted on the donor substrate and receptor substrate is obtained by combining the design position information and the actual mounting position obtained from image processing. The specific coordinates are the center of gravity position obtained from the shape of the microelement, and the coordinate origin is determined by referencing the position of the orientation flat of the substrate. Here, the position information on the donor substrate is called "position information D," and the position information on the receptor substrate is called "position information R."

[0091] The position information D includes microelements that are recognized as defective and should not be used for retransfer, as well as non-element locations that are not mounted at all. The position coordinates of these are calculated from adjacent microelements and acquired as "defective position information D." The same applies to "defective position information R" in the position information R.

[0092] Furthermore, in this example, the design pitch of the microelements arranged on the donor substrate is 1 / 4 of the design pitch of the microelements mounted on the receptor substrate, and the actual pitch has an error between the donor substrates and between the donor substrate and the receptor substrate. Therefore, this error is calculated from the position information D and R. For simplicity, in this example, the position information R is set to the design pitch, and the value of the error ΔPi of the pitch of the donor substrate relative to that pitch is +0.0075 [μm].

[0093] (2)Dividing process The area on the 6-inch donor substrate is divided into 27 divided areas ("divided areas D") as in Example 1. As shown in Figure 14, each area is 33 x 11 mm, and for convenience, the divided areas are indicated in the figure as A1 to A9, B1 to B9, and C1 to C9. The receptor substrate is also divided into 27 "divided areas R," and lifting is performed between opposing divided areas.

[0094] As in the first embodiment, the size of the divided area D is a design item determined by the effective aperture diameter of the reduction projection lens, the size of the photomask limited by other specifications, and the reduction projection magnification.

[0095] Here, the allowable range of the cumulative error amount obtained by multiplying the number of irradiation objects contained in divided area D in the long axis (X axis) direction, 660(-1), by the above-mentioned error ΔPi was set to ±5 [μm]. As shown in FIG. 15, when the upper left corner of division area D (dash line) is used as the alignment reference, this tolerance is arbitrarily set based on the limit at which the 50 μm square (dashed line in the figure), which is the size at which laser light passing through the opening (61) on the photomask (6) is focused on a 40 μm square microelement on the donor substrate, can irradiate the entire surface of the microelement (solid line) located at the right end, where the cumulative error is greatest. Note that the 40 μm square indicated by the two-dot dash line in the figure is the designed mounting position of the microelement on the donor substrate, and is located centrally relative to the image size indicated by the dashed line. In this embodiment, the cumulative error of all the microelements mounted within division area D is within the tolerance (659 × 0.0075 ≒ 4.94) relative to their designed positions, so there is no need to set a reduced "corrected division area D" in this division process.

[0096] (3) Selection process For a divided area R of the same size opposite the divided area D, microelements arranged in the divided area D that are located opposite to the non-element locations (approximately 91 locations of defective position information R), which account for approximately 1% of the 9075 microelements implemented in the divided area R, are selectively lifted one-to-one.

[0097] However, of the microelements (660 x 220 = 145,200) mounted within divided area D, there are 1,452 defective elements, which is approximately 1%, and these (defective position information D) may overlap with defective position information R. This is shown in Figure 16, which shows an image of the receptor substrate being observed through the donor substrate. A partial area of ​​the array of microelements arranged on the donor substrate is shown. This figure shows an enlarged view of the upper left area of ​​divided area A1, surrounded by a dashed line, and illustrates the array of microelements on the donor substrate located within this area.

[0098] Here, for convenience, the positions of the non-element areas where defective elements have been removed from the receptor substrate in a prior removal process are shown by open squares (Mr), the positions of microelements that are similarly mounted normally on the receptor substrate are shown by black squares (Er), and the positions of the microelements on the donor substrate, which are densely arranged at 16 times the density of the receptor substrate, are shown by gray squares (Ed). (Ed positions that overlap with Er and Mr are not shown.) As mentioned above, the pitch of the microelements Ed on the donor substrate is 50 μm, and the pitch of the microelements Er on the receptor substrate is 200 μm.

[0099] First, a case where the first receptor substrate is repaired using a donor substrate used for repair for the first time will be described. (3-1) The defect location information D and defect location information R are compared on a board-by-board basis to confirm in advance the locations where non-element locations (Mr) and defective element locations (Md) overlap. The overlap to be confirmed here refers to the overlap on a board-by-board basis (all 27 areas) at the locations where the β array group aligned in the X-axis direction of the donor board shown in the figure intersects with the α array group aligned in the Y-axis direction (a total of 245,025 locations per board). Note that the other α', α'', α''', β', β'', and β''' array groups represent the arrangement positions of other microelements on the donor board, which are mounted at 16 times the density. (In the figure, only the α array group is shown with arrows in the three rows from the left, and only the β array group is shown with arrows in the two rows from the top. The other "'" array groups are similarly shown with limited arrows.)

[0100] If there is no overlap, the position (Ed) of the microelement on the donor substrate corresponding to the non-element portion (Mr) is selected in the selection step. If an overlap is confirmed, the process will be described later.

[0101] (3-2) On the other hand, when repair is performed by combining a used donor substrate with a (first or) second or subsequent receptor substrate, the total position information (1% Md + used Md) including the position information of the approximately 1% of defective elements originally possessed by the donor substrate plus the position information of used substrates that are missing microelements due to past use in retransfer is compared with the distribution position information of the non-element areas on the receptor substrate (Mr) to check for overlaps in advance. If there is no overlap, the position (Ed) of the microelement on the donor substrate corresponding to the non-element area (Mr) is selected in the selection process.

[0102] (4) Transfer process In the above cases (3-1) or (3-2), after the position of the microelement on the donor substrate to be used for retransfer is selected, retransfer of the first or second or subsequent receptor substrates is initiated from the aforementioned divided area A1. The optical axis of the laser beam is scanned along the β column on the donor substrate via the photomask (6) and reduction projection lens (8) by the scanning mirror (4). Within this area, the excimer laser beam oscillates at the timing when the optical axis is scanned to the selected position, and the microelement mounted at the selected position on the donor substrate is lifted toward the opposing non-element area (Mr) on the receptor substrate.

[0103] (5) Moving process After area A1 of the receptor substrate has been repaired using a microelement located at a selected position within area A1 of the donor substrate, the next area A2 is repaired in the same manner. The areas are moved by moving the stage holding each substrate in any order (e.g., A1-A9 → B1-B9 → C1-C9), and all areas are repaired. The stage movement distance during the movement of each divided area is set to offset the cumulative error (approximately +4.95 μm) mentioned above. After repairs have been completed for all divided areas that require repair, the receptor substrate is replaced with the next receptor substrate to be repaired.

[0104] On the other hand, if overlaps are confirmed in the comparison by substrate unit in the above (3-1) or (3-2), the column group to be compared is changed from α to α' column group or from β to β' column group, and the combination of column groups after the change (intersection of the changed column groups) is compared by substrate unit in the same manner as in (3-1) or (3-2) above to check for overlaps. In this case, there are 15 possible combinations of column groups. If a combination of column groups without overlaps is found by substrate unit, the position (Ed) of the microelement on the donor substrate corresponding to the non-element portion (Mr) is selected based on that combination. Note that before the transfer process, the substrate is moved according to the combination of column groups. Figure 17 shows the positional relationship between the substrates during re-transfer between each divided area (A1).

[0105] Furthermore, if no non-overlapping combination of column groups is found in any of the 15 combinations in the substrate-by-substrate comparison in (3-1) or (3-2) above, comparison is performed not in broader substrate units but in narrower opposing divided areas. For example, comparison is limited to area A1 of the receptor substrate and area A1 of the opposing donor substrate. If there is no overlap at the intersection of the α column group and the β column group, the process proceeds directly to the transfer process. If there is overlap, other non-overlapping combinations of column groups (e.g., α' column group and β'' column group) are searched for, at least within the divided area (A1) of each opposing substrate. There are a maximum of 16 such combinations. After the correction of the receptor substrate divided area A1 using the donor substrate divided area A1 based on the found non-overlapping combination of column groups is completed, the next area A2 is subjected to similar comparison, and the receptor substrate area A2 is corrected using the non-overlapping combination of column groups. Thereafter, this process is repeated for donor A3 and receptor A3, donor A4 and receptor A4, etc. For example, if there is overlap only between divided areas B5, and there is no overlap on a substrate-by-substrate basis excluding this area, there is no need to compare areas limited to those before and after that.

[0106] If no non-overlapping combination of column groups is found in the aforementioned comparison between opposing divided areas (A1 and A1, B1 and B1, etc.), the area on the donor substrate to be compared is then changed from being limited to the opposing divided areas to being compared with the other 26 divided areas of the donor substrate, and non-overlapping combinations of column groups are searched for area by area. Figure 18 shows this process. In this example, for the combination of divided area C5 on the donor substrate and divided area A3 on the receptor substrate, for example, retransfer is performed at the intersection position of the α''' group and the β''' group. However, it should be noted that non-overlapping combinations of column groups must be searched for between divided areas, taking into account the defect position information (Md) that reflects the missing positions of the microelements that have been used for repair up until the time the divided area to be compared was changed. In addition, it is necessary to comprehensively consider (calculate) whether a reasonable takt time can be achieved, taking into account the time required for frequent column group movement and stage movement to move to the opposing divided area. Based on the calculation results, the overlapping collation range is appropriately selected and the timing of donor substrate replacement is determined.

[0107] As long as direct irradiation of the laser beam onto the receptor substrate does not have an adverse effect, there is also the option of carrying out the transfer process regardless of whether there is overlap of defect position information, and leaving the non-element areas that were not re-transferred due to overlap to be repaired a second time or later using a different donor substrate. Furthermore, it is possible to combine verification for each substrate and verification for each divided area as appropriate based on a simulation of the takt time, and furthermore, it is also possible to determine the combination of each verification method and its range that will result in the shortest simulated takt time based on the position information of each substrate obtained in advance in the inspection process.

[0108] When retransferring for each divided area R, as in this embodiment, that is, when retransferring by scanning a scanning mirror with a scan speed of approximately 30 / second for each number of apertures on the photomask (165 x 55) in one go, assuming there is no overlap of defective positions between substrates, the time required to repair one divided area (approximately 90 locations) is approximately 3 seconds.Even when taking into account the time required to do this for 27 divided areas and the time required to move each substrate to move between divided areas, the time required from when the substrate is set to when the repair is completed is roughly around 90 seconds.

[0109] Compared to the takt time of approximately 2,450 seconds required for the retransfer of one microelement using the aforementioned conventional device, this method can repair up to 1% of defective elements at an overwhelmingly faster rate. Furthermore, even when taking into account the calculation time required for collation (duplicate confirmation) and the stage movement time required for the above-mentioned column group movement and divided area movement to avoid duplication, the overwhelming superiority of the takt time in this embodiment can be maintained.

[0110] In addition, when comparing divided areas randomly without being limited to opposing divided areas, or when taking the cumulative error amount into consideration, it is preferable to determine the size of the corrected divided area D, the combination of the movement amounts of each stage, and the order of performing each process so as to minimize the time required for mounting or re-transferring the entire receptor substrate using a simulation program with parameters of the position information D, position information R obtained in the inspection process, the size of the divided area D, and the allowable range of the cumulative error amount, and then optimize each process.

[0111] Although the embodiments of the present invention have been described in detail above, the present invention can be expressed from different perspectives as follows (1) to (19). (1) A scanning type reduction projection optical system used in a laser processing device that irradiates a laser beam onto an object to be irradiated to induce a reaction, the scanning type reduction projection optical system having an infinity correction optical system, a scanning mirror, and a photomask. (2) A laser processing device that irradiates a laser beam onto an object to be irradiated to induce a reaction, the laser processing device having a laser device that oscillates the laser beam, an infinity correction optical system, and a scanning mirror. (3) A lifting device for irradiating a laser beam onto a donor substrate on which an irradiation object is provided and for moving the irradiation object from the donor substrate to a receptor substrate, the lifting device having a laser device for emitting the laser beam, an infinity correction optical system, and a scanning mirror. (4) A laser processing method in which a laser beam is irradiated onto an object to be irradiated to induce a reaction, characterized in that the laser beam is irradiated onto the object to be irradiated using a scanning reduction projection optical system having an infinity correction optical system, a scanning mirror, and a photomask. (5) A lifting method for irradiating a laser beam onto a donor substrate on which an irradiation object is provided, and moving the irradiation object from the donor substrate to a receptor substrate, characterized in that the laser beam is irradiated onto the irradiation object using a scanning reduction projection optical system having an infinity correction optical system, a scanning mirror, and a photomask. (6) A method for manufacturing a substrate having an irradiation object mounted thereon, comprising irradiating a laser beam toward a donor substrate on which the irradiation object is provided, and moving the irradiation object from the donor substrate to a receptor substrate, the method comprising irradiating the laser beam toward the irradiation object using a scanning reduction projection optical system having an infinity correction optical system, a scanning mirror, and a photomask. (7) The method for manufacturing a substrate on which an irradiation object is mounted according to (6), wherein the irradiation object is a microelement. (8) The method for manufacturing a substrate on which an irradiation object is mounted according to (7), wherein the microelement is a micro LED. (9) The method for manufacturing a substrate on which an irradiation target is mounted according to (7) or (8), wherein the microelements are arranged in a matrix on the donor substrate. (10) The method for manufacturing a substrate on which an irradiation object is mounted according to (6), wherein the irradiation object is a film. (11) The method for manufacturing a substrate on which an irradiation object is mounted according to (10), wherein the film is a conductive film or an adhesive film. (12) The method for manufacturing a substrate on which an object to be irradiated is mounted according to (10), wherein the film is an organic EL film. (13) A method for manufacturing a substrate having a microelement mounted thereon, comprising the steps of irradiating a laser beam onto a first donor substrate having a film thereon, transferring the film from the first donor substrate to a receptor substrate, and obtaining a substrate having a film mounted thereon, and irradiating a laser beam onto a second donor substrate having a microelement thereon, and transferring the microelement from the second donor substrate onto the film of the substrate having the film mounted thereon, wherein the method for manufacturing a substrate having a microelement mounted thereon is characterized in that the laser beam is irradiated onto the film or the microelement using a scanning reduction projection optical system having an infinity correction optical system, a scanning mirror, and a photomask. (14) A method for removing a defective portion of a donor substrate having a defective portion, by irradiating the defective portion with laser light to remove the defective portion from the donor substrate, characterized in that the laser light is irradiated toward the defective portion using a scanning reduction projection optical system having an infinity correction optical system, a scanning mirror, and a photomask. (15) A retransfer method for irradiating a donor substrate on which an irradiation object is provided with laser light and moving the irradiation object from the donor substrate to a receptor substrate, wherein the receptor substrate has an area where the irradiation object is already mounted and a defective area where the irradiation object is not mounted in the planned mounting area, and the retransfer method is characterized in that laser light is irradiated onto the irradiation object provided on the donor substrate using a scanning reduction projection optical system having an infinity correction optical system, a scanning mirror, and a photomask, and the irradiation object is moved to the defective area on the receptor substrate. (16) A lifting method for irradiating a laser beam onto a donor substrate on which an irradiation object is provided, and moving the irradiation object from the donor substrate to a receptor substrate, characterized in that the irradiation object provided on the donor substrate has a defective area, and the laser beam is irradiated onto the irradiation object other than the defective area using a scanning reduction projection optical system having an infinity correction optical system, a scanning mirror, and a photomask, and the irradiation object is moved to the receptor substrate. (17) A laser processing method in which a laser beam is irradiated onto an object to be irradiated to induce a reaction, characterized in that the laser beam is scanned by a scanning mirror and focused on a photomask as an image plane of an infinity-corrected optical system, and the laser beam that passes through the photomask is projected in a reduced size onto the object to be irradiated. (18) A lifting method for irradiating a donor substrate on which an irradiation object is provided with laser light and moving the irradiation object from the donor substrate to a receptor substrate, characterized in that the laser light is scanned by a scanning mirror and focused on a photomask as an image plane of an infinity correction optical system, and the laser light that passes through the photomask is projected in a reduced size onto the irradiation object. (19) A method for manufacturing a substrate having an irradiation object mounted thereon, comprising irradiating a laser beam toward a donor substrate on which the irradiation object is provided, and moving the irradiation object from the donor substrate to a receptor substrate, wherein the laser beam is scanned by a scanning mirror and focused on a photomask as an image plane of an infinity corrected optical system, and the laser beam that has passed through the photomask is projected in a reduced size onto the irradiation object. (20) A scanning type reduction projection optical system used in a laser processing device that irradiates a laser beam onto an irradiation object to induce a reaction, A scanning reduction projection optical system having a first lens array, a second lens array, a scanning mirror, and a photomask. (21) The scanning reduction projection optical system according to (20), wherein the first lens array or the second lens array is formed by arranging lens elements. (22) The scanning reduction projection optical system according to (21), wherein the lens element is of a fly's eye type, a cylindrical type, or a spherical type. (23) The scanning reduction projection optical system according to any one of (20) to (22), wherein the first lens array or the second lens array is a combination of uniaxial cylindrical lenses arranged at right angles. (24) The scanning reduction projection optical system according to any one of (20) to (23), wherein an array mask is disposed immediately before the first lens array. (25) The scanning reduction projection optical system according to any one of (20) to (24), wherein an array mask is disposed between the first lens array and the second lens array. (26) A scanning type reduction projection optical system according to (24) or (25), wherein the array mask has a group of apertures. (27) The scanning reduction projection optical system according to (26), wherein the apertures forming the aperture group are circular, elliptical, square or rectangular. (28) The scanning reduction projection optical system according to (26) or (27), wherein the size of the apertures forming the aperture group is smaller than the size of the lens elements. (29) The scanning reduction projection optical system according to any one of (24) to (28), wherein the array mask has at least two types of aperture groups. (30) The scanning reduction projection optical system according to (29), wherein the at least two types of aperture groups differ from each other in the size, shape, number, or arrangement of the apertures forming each aperture group. (31) A scanning type reduction projection optical system used in a laser processing device that irradiates a laser beam onto an irradiation object to induce a reaction, A scanning reduction projection optical system that is telecentric only on the image side. (32) A method for removing a defective portion, comprising irradiating a laser beam onto a defective portion of a donor substrate having the defective portion, and removing the defective portion from the donor substrate, the method comprising the steps of: A method for removing a defective portion, comprising irradiating the defective portion with a laser beam using a scanning type reduction projection optical system having a galvano scanner and a photomask. (33) The method for removing a defective portion according to (32), wherein the photomask has circular, elliptical, square, or rectangular openings. (34) The method for removing a defective portion according to (32) or (33), wherein the photomask has an area in which openings are arranged in a matrix. (35) The method for removing a defective portion according to any one of (32) to (34), wherein the photomask has at least two types of opening groups. (36) The method for removing a defective portion according to (35), wherein the at least two types of opening groups differ from each other in the size, shape, number, or arrangement of the openings forming each opening group. (37) A retransfer method comprising: irradiating a donor substrate on which an irradiation object is provided with laser light; and transferring the irradiation object from the donor substrate to a receptor substrate, the retransfer method comprising the steps of: the receptor substrate has an area where the irradiation object is mounted in advance and a defective area where the irradiation object is not mounted in the planned mounting area; A retransfer method comprising: irradiating a laser beam onto an irradiation object provided on the donor substrate using a scanning reduction projection optical system having a galvanometer scanner and a photomask; and moving the irradiation object to the defective area on the receptor substrate. (38) A lifting method for irradiating a donor substrate on which an irradiation object is provided with a laser beam, and moving the irradiation object from the donor substrate to a receptor substrate, comprising: the irradiation object provided on the donor substrate has a defective area; A lifting method, characterized in that a laser beam is irradiated onto an irradiation object other than the defective area using a scanning type reduction projection optical system having a galvano scanner and a photomask, and the object is moved to the receptor substrate.

[0112] Each of the constituent elements in many of the above-described embodiments can be subdivided, and the subdivided constituent elements can be introduced into these (1) to (38) either singly or in combination. Representative examples include the use and arrangement of various lenses, the type of laser light, various configurations and control methods of laser processing equipment, the type and shape of photomasks, the shape and arrangement of openings, the type and shape of irradiation targets, the reaction mechanism of laser lift-off, and the mechanism of the optical system. [Industrial Applicability]

[0113] It can be used as part of the manufacturing process for micro LED displays.

Claims

1. A lifting method for irradiating a substrate on which a film is provided with laser light and moving the film from the substrate to another substrate, comprising: the other substrate has an area where a microelement has been mounted in advance and a defective area where a microelement has not been mounted in the area where the microelement is to be mounted; A lifting method characterized by using a scanning reduction projection optical system having a galvanometer scanner and a photomask to irradiate laser light onto a film provided on the substrate, and moving the film to the defective area of ​​the other substrate.

2. A lifting method as described in claim 1, wherein the membrane is a conductive membrane or an adhesive membrane.

3. A lifting method as described in claim 1, wherein the film is a conductive paste film.

4. A lifting method described in any one of claims 1 to 3, wherein the micro-element is a micro-LED.

5. A lifting method described in any one of claims 1 to 3, wherein the microelements are arranged in a matrix on the other substrate.

6. A lifting method described in any one of claims 1 to 5, wherein the photomask has a circular, elliptical, square or rectangular opening.

7. A lifting method described in any one of claims 1 to 6, wherein the photomask has an area in which openings are arranged in a matrix pattern.

8. A retransfer method for transferring a microelement from a substrate to another substrate by irradiating a laser beam onto the substrate on which the microelement is provided, the method comprising: The other substrate is a substrate obtained by the lifting method according to any one of claims 1 to 7, A retransfer method characterized by irradiating laser light onto a microelement provided on the substrate using a scanning reduction projection optical system having a galvanometer scanner and a photomask, and moving the microelement onto a film that has been previously moved to the defective area of ​​the other substrate.

9. A method for manufacturing a display, characterized in that defective parts are repaired by the retransfer method described in claim 8.

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