JP7638650B2 - Chip transfer method and chip transfer device - Google Patents

Description

The present invention relates to a chip transfer method and a chip transfer device, and more specifically, to a chip transfer method and a chip transfer device that can transfer multiple chips to a specified position on a transfer substrate using a mask on which a pattern is formed.

A micro light emitting diode (LED) display device is a display device in which all pixels that make up the screen are made of micro LED chips. Micro LED display devices consume less power than liquid crystal display (LCD) devices, are more durable, have high luminous efficiency, can be made lighter and smaller, are advantageous for large area display, and are said to be the next generation of stretchable display devices, and active efforts are being made in this field.

The manufacturing process of a micro LED display device includes an epitaxial process, a chip process, a transfer process, and a bonding process. Among them, the transfer process is, for example, a process of transferring a large number of micro LED chips onto a substrate on which various wiring and thin film transistors are formed to form pixels.

For example, a transfer substrate is provided on a wafer on which micro LED chips are manufactured, and then the micro LED chips are attached to the transfer substrate and detached from the wafer. The transfer substrate is then positioned on a transfer substrate on which various wiring and thin film transistors are formed, and the micro LED chip is then detached from the transfer substrate and transferred to a specified position on the transfer substrate.

Micro LED chips are extremely small, measuring less than 100 micrometers, and are difficult to handle due to their small size. Therefore, there are significant difficulties in transferring micro LED chips individually, for example, from a transfer substrate to a transfer substrate.

The technology behind this invention is described in the following patent documents:

KR10-2019-0072196A

The present invention provides a chip transfer device and method that can transfer multiple chips simultaneously to a specified position on a transfer substrate using a mask on which a pattern is formed.

A chip transfer method according to an embodiment of the present invention includes the steps of providing a transfer substrate having a plurality of chips on a transferee substrate, emitting a line beam, shaping the line beam into a plurality of pattern beams using a mask provided in the path of the line beam, irradiating the transfer substrate with the pattern beam to detach the plurality of chips from the transfer substrate, and placing the plurality of chips detached from the transfer substrate on the transferee substrate.

The step of separating the plurality of chips may include a step of irradiating the plurality of pattern beams in correspondence with the plurality of chips to be separated from the transfer substrate.

The chip transfer method may further include a pattern replacement step of changing the position of the mask so that the line beam can pass through a pattern of the multiple patterns formed on the mask whose size corresponds to each of the multiple chips, and be shaped into the pattern beam.

The chip transfer method may include a step of shaping a marker beam from the line beam using the mask provided in the path of the line beam, a step of irradiating the marker beam onto the transfer substrate and capturing an image of the marker beam on the transfer substrate to generate a marker beam image, and a primary alignment step of aligning the position of the mask relative to the transfer substrate using the marker beam image.

The steps of shaping the pattern beam and shaping the marker beam are performed simultaneously using the same line beam, but the marker beam may be shaped from a portion of the line beam and the pattern beam may be shaped from the remaining portion.

The chip transfer method may include a step of irradiating the pattern beam onto the transfer substrate and capturing an image of the pattern beam that has passed through the transfer substrate to generate a pattern beam image, and a secondary alignment step of using the pattern beam image to align the gradient and distance of the mask relative to the transfer substrate for focusing the pattern beam that passes through the mask and is irradiated onto the transfer substrate.

The step of shaping the marker beam may include a step of passing the line beam through a pair of alignment markers formed on both sides of a pattern whose size matches that of the multiple chips, among a plurality of alignment markers formed on both sides of the plurality of patterns, to form a pair of marker beams on both sides of the pattern beam.

The step of generating the marker beam image may include a step of photographing a pair of alignment marks formed on the transfer substrate by the pair of marker beams irradiated from above to below the transfer substrate, and a step of inserting the reference marks into the photographed image of the alignment marks using the coordinates of the reference marks displayed on the transfer substrate so as to correspond to the marker beams as a guide.

The primary alignment procedure may include a step of calculating an offset of the alignment mark relative to the reference mark from the marker beam image, and a step of adjusting the position and gradient of the mask by an amount corresponding to the offset in a direction intersecting with the line beam propagation direction so that the alignment mark can be aligned with the reference mark.

The step of generating the pattern beam image may include a step of capturing a focal image of the multiple pattern beams while scanning the transfer substrate from above to below along the direction in which the multiple pattern beams that have passed through the transfer substrate are arranged.

The secondary alignment procedure may include a procedure of collecting characteristics of the multiple pattern beams from the focused image and comparing the collected characteristics with a target characteristic, and a procedure of adjusting the position and gradient of the mask in the direction of travel of the line beam so that the collected characteristics match the target characteristic.

The chip transfer device according to an embodiment of the present invention is a chip transfer device that transfers multiple chips from a transfer substrate to a transferee substrate, and includes a mask on which a pattern is formed so that a line beam can be shaped into multiple pattern beams and irradiated onto the transfer substrate, a mask support unit that supports the mask so that it can be moved and rotated freely, and a laser light source unit that emits a line beam toward the mask so that multiple chips can be transferred.

The mask may have a plurality of patterns of different sizes formed thereon, and any one of the plurality of patterns may correspond in size to each of the plurality of chips.

The chip transfer device may further include a pattern replacement unit that controls the mask support unit to change the position of the mask so that the line beam passes through one of the multiple patterns whose size matches that of the multiple chips attached to the transfer substrate.

The multiple patterns each have multiple pattern holes, and the pattern holes arranged on the same line in the width direction of the line beam may have the same shape, size, and arrangement, and the pattern holes arranged in a direction intersecting the width direction of the line beam may have different shapes, sizes, and arrangements.

A plurality of alignment markers are formed on both sides of the plurality of patterns in the width direction of the line beam, and the plurality of alignment markers are aligned on the same line as the plurality of patterns in the width direction of the line beam, and the plurality of pattern beams that have passed through a pattern whose size matches the plurality of micro LED chips and a pair of marker beams that have passed through a pair of alignment markers located on both sides of the pattern whose size matches the plurality of micro LED chips may be irradiated simultaneously onto the transfer substrate.

The chip transfer device may include a first alignment monitoring unit that captures the pair of marker beams irradiated onto the transfer substrate to generate a marker beam image, and a first alignment adjustment unit that controls the mask support unit to change the position and gradient of the mask in a direction intersecting the traveling direction of the line beam so that a pair of alignment marks formed on the transfer substrate by the pair of marker beams irradiated onto the transfer substrate from above to below the transfer substrate coincide with guide marks displayed on the transfer substrate to correspond to the pair of marker beams.

The chip transfer device may also include a second alignment monitoring unit that captures focal images of the multiple pattern beams that have passed through the transfer substrate and generates them as a pattern beam image, and a second alignment adjustment unit that controls the mask support unit to change the position and gradient of the mask in the traveling direction of the line beam so that the characteristics of the multiple pattern beams collected from the focal images of the multiple pattern beams that have passed through the transfer substrate from above to below the transfer substrate match target characteristics.

According to an embodiment of the present invention, a mask having a pattern formed thereon can be used to simultaneously transfer multiple chips to a predetermined position on a transfer substrate.

For example, when applied to the transfer process of micro LED chips, when extremely small micro LED chips measuring 100 micrometers in size are transferred from a transfer substrate to a transfer substrate, multiple micro LED chips can be transferred at once to the transfer substrate in an amount corresponding to the number of multiple pattern beams shaped using the pattern.

This allows the process time to be shortened and the productivity of the micro LED chip transfer process to be improved.

1 is a schematic diagram of a chip transfer device according to an embodiment of the present invention. 1 is a schematic diagram of a mask having multiple different patterns formed thereon in accordance with an embodiment of the present invention; 1 is a process flow diagram of a chip transfer process using a chip transfer method and device according to an embodiment of the present invention. 1 is a process flow diagram of a chip transfer process using a chip transfer method and device according to an embodiment of the present invention. 1 is a process flow diagram of a chip transfer process using a chip transfer method and device according to an embodiment of the present invention. 1 is a process flow diagram of a chip transfer process using a chip transfer method and device according to an embodiment of the present invention. 1 is a process flow diagram of a chip transfer process using a chip transfer method and device according to an embodiment of the present invention. 1 is a flowchart showing a chip transfer method according to an embodiment of the present invention.

Hereinafter, the embodiments of the present invention will be described in more detail with reference to the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below, but may be embodied in various different forms, and these embodiments are provided merely to complete the disclosure of the present invention and to fully convey the scope of the invention to those skilled in the art. In describing the present invention, the same reference numerals are used for the same components, and the drawings may be partially exaggerated in size to accurately describe the embodiments of the present invention, and the same numerals in the drawings indicate the same components.

The chip transfer method and device according to the embodiment of the present invention provide the technical feature of being able to transfer multiple chips simultaneously to a specified position on a transfer substrate using a mask on which a pattern is formed.

In addition, the chip transfer method and apparatus according to an embodiment of the present invention presents a technical feature that allows for the transfer of multiple chips of different sizes onto a substrate using a single mask on which multiple different patterns are formed.

The chip transfer method and apparatus according to an embodiment of the present invention can be used in the transfer process of micro LED chips using a laser beam.

Needless to say, the chip transfer method and apparatus according to the embodiments of the present invention can also be used in various processes in which a laser beam is used to transfer various electronic elements from a sacrificial substrate to a target substrate.

Below, we will explain in detail the chip transfer method and device according to an embodiment of the present invention, based on the micro LED chip transfer process.

Figure 1 is a schematic diagram of a chip transfer device according to an embodiment of the present invention, and Figure 2 is a schematic diagram of a mask on which multiple patterns are formed according to an embodiment of the present invention. Figures 3 to 7 are process flow diagrams of a micro LED chip transfer process using a chip transfer method and device according to an embodiment of the present invention.

A chip transfer device according to an embodiment of the present invention will be described with reference to Figures 1 to 7. The chip transfer device may also be referred to as a micro LED chip transfer device.

The chip transfer device according to an embodiment of the present invention is a chip transfer device that transfers multiple chips, for example multiple micro LED chips 1, from a transfer substrate S' to a transfer substrate S, and includes a mask 10 on which a pattern P is formed so that a pattern beam L' can be shaped from a line beam L to be irradiated onto the transfer substrate S', a mask support unit 20 that supports the mask 10 so as to be movable and rotatable, and a laser light source unit 30 that emits a line beam L toward the mask 10 so that multiple micro LED chips 1 can be transferred. The chip transfer device may also include a reflection mirror unit 40 that reflects the multiple pattern beams L' shaped as they pass through the mask 10 onto the transfer substrate S'.

At this time, multiple patterns P of different sizes may be formed on the mask 10. More specifically, multiple patterns P of different shapes, sizes, and arrangements may be formed on the mask 10. Any one of the multiple patterns P may correspond in size to each of the multiple micro LED chips 1.

Here, "the sizes correspond" means that the size of one micro LED chip 10 and the size of one pattern beam L' match within a predetermined error value. In this case, the size of one pattern beam may be relatively larger than the size of one micro LED chip 10 within the error value. Meanwhile, the error value is also called a margin.

In addition, any one of the multiple patterns P may have the same shape and arrangement as each of the multiple micro LED chips 1.

The chip transfer device may further include a pattern replacement unit 50 that controls the mask support unit 20 to change the position of the mask 10 so that the line beam L passes through a pattern among the multiple patterns P that matches the size of the multiple micro LED chips 1 attached to the transfer substrate S'.

The chip may be a micro LED chip 1. Needless to say, the chip may include various electronic element chips in addition to the micro LED chip 1.

The micro LED chip 1 may be manufactured by growing a thin film of inorganic materials such as Al, Ga, N, P, As, and In on a sapphire or silicon substrate. The micro LED chip 1 may have a size of, for example, 10 to 100 micrometers. The micro LED chip 1 may include blue, green, and red micro LED chips. The manufactured micro LED chip 1 may be detached from the sapphire or silicon substrate and attached to a transfer substrate S'. Alternatively, the micro LED chip 1 may be directly manufactured by growing a thin film of inorganic materials such as Al, Ga, N, P, As, and In on a transfer substrate S'.

The transfer substrate S' may be a wafer on which a plurality of micro LED chips 1 are attached in an array. Needless to say, the plurality of micro LED chips 1 may be grown directly on the transfer substrate S'. The transfer substrate S' may also be referred to as a temporary substrate.

In the following, for ease of explanation, the transfer substrate will sometimes be referred to as substrate S for short.

The substrate S may be glass. Various wiring and thin film transistors may be formed on the substrate S. Blue, green and red micro LED chips may be transferred from the transfer substrate S' to the pixel region of the substrate S using a chip transfer device. Needless to say, the type and material of the substrate S may be changed in various ways. Meanwhile, the substrate S may also be referred to as a target substrate. The substrate S and the various wiring and thin film transistors formed on the substrate S may be made of, for example, a transparent material.

The transfer substrate S' may be supported on a first stage (not shown), and the substrate S may be supported on a second stage (not shown). The first and second stages may be housed inside a chamber (not shown) and may face each other in the vertical direction Y.

The first stage may be formed, for example, in the shape of a square plate or a disk, and may have an opening in the center. The area of the first stage may be formed to be larger than the area of the transfer substrate S', and the area of the opening may be formed to be smaller than the area of the transfer substrate S'.

The first stage may have a suction device (not shown) disposed at its bottom. The suction devices may be arranged along the periphery of the opening. The transfer substrate S' may be supported by being sucked to the bottom of the first stage by the suction device. At this time, a part of the upper surface of the transfer substrate S' may be exposed to the outside through the opening. This allows the pattern beam L' to be irradiated onto the transfer substrate S' through the opening. Meanwhile, the shape of the first stage and the manner in which the first stage supports the transfer substrate S' may be changed in various ways.

The second stage may be disposed below the first stage. The second stage serves to support the substrate S. The second stage may be, for example, rectangular in shape. The substrate S may be placed on and supported on the upper surface of the second stage. The area of the upper surface of the second stage may be formed to be larger than the area of the substrate S. Meanwhile, the structure and shape of the second stage may be modified in various ways.

The transfer substrate S' is placed on the first stage, and the substrate S is placed on the second stage, so that the transfer substrate S' and the substrate S face each other in the vertical direction.

The chip transfer device may further include first and second drive units (not shown). The first and second drive units can move and rotate the first and second stages separately. Therefore, the first and second stages can be moved separately using the first and second drive units to align the transfer substrate S' and the substrate S in the vertical direction Y.

The first drive unit can move the first stage in the forward/backward direction Z, the left/right direction X, and the up/down direction Y, and can rotate it around the up/down direction Y. The second drive unit can move the second stage in the forward/backward direction Z, the left/right direction X, and the up/down direction Y, and can rotate it around the up/down direction Y. The configurations and methods of the first and second drive units for this purpose can be modified in various ways.

The mask 10 may be supported by the mask support section 20, or may be disposed between the reflecting mirror section 40 and the laser light source section 30. Therefore, the mask 10 can shape the line beam L traveling from the laser light source section 30 to the reflecting mirror section 40 into the shape of the pattern P arranged on the mask 10 by passing the line beam L through the pattern P. The pattern beam L', which has been shaped into the shape of the pattern P, can be reflected by the reflecting mirror section 40 and irradiated onto the transfer substrate S'.

The mask 10 may be formed in a plate shape. A pattern P may be formed on the mask 10. The pattern P may have a plurality of pattern holes. The plurality of pattern holes may be aligned in the width direction of the line beam L or may form a single row, and serve to pass the line beam L and shape it into the shape of the pattern P.

Needless to say, multiple patterns P may be formed on the mask 10. These multiple patterns P serve to shape the line beam L into a pattern by passing it through. The multiple patterns P may be arranged in the vertical direction Y.

The multiple patterns P may also be referred to as a pattern P of multiple rows r. Here, the multiple rows r may include, for example, a first row r1, a second row r2, a third row r3, a fourth row r4, and a fifth row r5. The multiple patterns P are formed along each row, and may include a first row pattern P1, a second row pattern P2, a third row pattern P3, a fourth row pattern P4, and a fifth row pattern P5. Needless to say, the number of multiple rows can be changed in various ways.

Each of the multiple patterns P may have multiple pattern holes. A single pattern P may be formed by multiple pattern holes arranged on the same line in the left-right direction X forming a single row.

The line beam L passes through the multiple pattern holes, and the shape of the line beam L can be shaped to the shape of the pattern holes. That is, a portion of the line beam L that reaches the mask 10 can pass through the multiple pattern holes and be shaped into a pattern beam L', and the remainder may not be able to pass through the mask 10. Therefore, the pattern beam L' that passes through the multiple pattern holes can be irradiated onto the transfer substrate S' in the same pattern shape as the multiple pattern holes.

The pattern holes that are arranged on the same line in the width direction of the line beam L, for example in the left-right direction X, to form one pattern P may have the same shape, size, and arrangement. That is, the pattern holes that form the same row r have the same shape, size, and arrangement. Here, arrangement refers to the left-right spacing between the pattern holes. In this way, pattern holes of the same shape, size, and arrangement can be arranged in the left-right direction X to form one line.

In addition, the pattern holes arranged in a direction intersecting the width direction of the line beam L, for example, in the height direction Y, may differ from each other in at least one of the shape, size, and arrangement. In other words, when the rows r are different, at least one of the shape, size, and arrangement of the pattern holes may differ from each other. For example, lines having pattern holes of different shapes, sizes, and arrangements may be arranged in the vertical direction Y.

That is, the pattern holes of the first row pattern P1 formed along the first row r1 and the pattern holes of the second row pattern P2 formed along the second row r2 differ from each other in at least one of their shapes, sizes, and arrangements. Similarly, the pattern holes of the first row pattern P1 and the pattern holes of the third row pattern P3 also differ from each other in at least one of their shapes, sizes, and arrangements. That is, the pattern holes of the patterns formed along each row r differ from each other in at least one of their shapes, sizes, and arrangements. Therefore, the mask 10 can shape the pattern beam L' in various ways according to the number of patterns P. That is, the shape, size, and arrangement of the pattern beam L' irradiated to the transfer substrate S' can be determined according to the shape, size, and arrangement of the pattern P through which the line beam L passes.

A plurality of alignment markers M may be formed on both sides of the plurality of patterns P in the width direction of the line beam L. The plurality of alignment markers M may include, for example, a first row alignment marker M1, a second row alignment marker M2, a third row alignment marker M3, a fourth row alignment marker M4, and a fifth row alignment marker M5. These alignment markers M may be aligned on the same line as the plurality of patterns P in the width direction of the line beam.

For example, the pattern and the alignment marker in the first row may be located on the same line in the left-right direction X. Similarly, the patterns and the alignment marker in each of the remaining rows may be located on the same line in the left-right direction X. The alignment marker may be called an alignment hole. The alignment marker may be formed in a cross shape. Therefore, the marker beam L _M shaped while passing through the alignment marker can be displayed in a cross shape on the transfer substrate S'. Needless to say, the shape of the alignment marker can be changed in various ways.

The line beam L extending in the left-right direction X can be shaped into a plurality of pattern beams L' and marker beams L _M while passing through pattern holes and alignment markers formed in any one of the plurality of rows, and can be irradiated in a plurality of dots onto the transfer substrate S'. At this time, the shape and size of the pattern beam irradiated onto the transfer substrate S can be determined according to the shape and size of the pattern holes in the row through which the line beam L passes. Meanwhile, the shape and position of the cross-shaped marker beam L _M irradiated onto the transfer substrate S' may be observed to check the alignment of the mask 10 with respect to the transfer substrate S'.

The mask support part 20 may support the mask 10 so that it can move and rotate freely. For example, the mask support part 20 may support the mask 10 so that it can move freely in the left-right direction X, the front-back direction Z, and the up-down direction Y. In this case, the mask support part 20 may support the four upper, lower, left, and right corner parts of the mask 10 so that they can each move by different distances in the front-back direction Z. In addition, the mask support part 20 may support the mask 10 so that it can rotate around the front-back direction Z.

The mask support section 20 may be separated upward from the first stage on which the transfer substrate S' is supported, or may be located between the laser light source section 30 and the reflection mirror section 40. The mask support section 20 may extend in the up-down direction Y and the left-right direction X and have a predetermined area, and may have a predetermined thickness in the front-back direction Z. The mask support section 20 may be, for example, a square plate with an opening in the center. Needless to say, the shape of the mask support section 20 can be changed in various ways. The mask support section 20 plays a role in supporting the mask 10.

The mask support part 20 may support the periphery of the mask 10. Through an opening in the center of the mask support part 20, the multiple patterns P and alignment markers M formed in the center of the mask 10 may be exposed to the laser light source part 30.

The mask support section 20 may be provided with a driver (not shown). The driver may include at least one of a front-rear driver (not shown), a left-right driver (not shown), a top-bottom driver (not shown), and a rotation driver (not shown). The mask 10 may be supported by the driver. The mask support section 20 may use the driver to adjust the position and gradient of the mask 10 in multiple directions.

The mask support unit 20 may change the position of the mask 10 so that the line beam L can pass through the pattern P that matches the size, shape, and arrangement of the micro LED chips 1 attached to the transfer substrate S. That is, the mask support unit 20 may move and rotate the mask 10 in multiple directions so that the pattern P through which the line beam L should pass can be selected from among the multiple patterns P. Thus, the mask 10 can pass the line beam L through any one row pattern among the multiple patterns P whose shape, size, and arrangement match those of the multiple micro LED chips 1 attached to the transfer substrate S'. Therefore, the shape, size, and arrangement of the pattern beam L' to be irradiated to the transfer substrate S' can be selected to match those of the micro LED chips 1.

The laser light source unit 30 may be separated from the mask 10, for example, in the front-to-back direction Z, and may emit a laser beam toward the mask 10, for example, in the shape of a line beam L. The line beam L may extend in the left-to-right direction X, or may be emitted in the front-to-back direction Z. The laser source of the laser light source unit 30 may be changed in various ways.

The reflecting mirror unit 40 may be spaced above the transfer substrate S' and face the mask 10 in the front-to-rear direction Z. The reflecting mirror unit 40 may reflect the multiple pattern beams L' shaped as they pass through the mask 10 onto the transfer substrate S'. The reflecting mirror unit 40 may be positioned so that it is inclined at 45° to the traveling direction of the pattern beams L'.

The reflection mirror unit 40 may reflect the plurality of pattern beams L' that have passed through a pattern whose size matches the plurality of micro LED chips, and the pair of marker beams L _M that have passed through a pair of align markers located on both sides of the pattern whose size matches the plurality of micro LED chips, to the transfer substrate S'. This makes it possible for the plurality of pattern beams L' and the pair of marker beams L _M to be irradiated simultaneously onto the transfer substrate S'.

The pattern beam L' and the marker beam L _M may travel in the forward/backward direction Z between the mask 10 and the reflecting mirror section 40, or may be reflected downward at the reflecting mirror section 40 and travel in the upward/downward direction toward the transfer substrate S'.

The pattern replacement unit 50 may change the position of the mask 10 by controlling the mask support unit 20 so that the line beam L passes through a pattern among the multiple patterns P whose size matches that of the multiple micro LED chips 1 attached to the transfer substrate S'.

The pattern replacement unit 50 may receive information regarding the size, shape, and arrangement of the micro LED chips 1 attached to the transfer substrate S' from a process controller (not shown) that performs the micro LED chip transfer process, select a pattern that matches the input size, shape, and arrangement of the micro LED chips 1, and change the position of the mask 10 by controlling the mask support unit 20 to pass the line beam L through the selected pattern.

Meanwhile, the micro LED chip transfer device according to an embodiment of the present invention may include a first alignment monitoring unit 60, a first alignment adjustment unit 70, a second alignment monitoring unit 80, and a second alignment adjustment unit 90.

The first alignment monitoring unit 60 may be an optical camera. A plurality of first alignment monitoring units 60 may be arranged above the transfer substrate S'. The first alignment monitoring unit 60 may capture the marker beam L _M irradiated onto the transfer substrate S' to generate a marker beam image. The first alignment monitoring unit 60 may check the position and shape of the marker beam L _M irradiated onto the transfer substrate S'.

The first alignment adjustment unit 70 may control the mask support unit 20 to change the position and gradient of the mask in a direction intersecting the traveling direction of the line beam L so that a pair of alignment marks formed on the transfer substrate S' by _a pair of marker beams L _M irradiated onto the transfer substrate S' from above to below coincide with a reference mark displayed on the transfer substrate S' corresponding to the marker beams L M. The first alignment adjustment unit 70 may receive a marker beam image from the first alignment monitoring unit 60, and may control the mask support unit 20 in accordance with the position and shape of the alignment mark displayed in the marker beam image to adjust the alignment of the mask 10.

The position of the mask 10 relative to the transfer substrate S' can be primarily aligned by using the first alignment monitoring unit 60 and the first alignment adjustment unit 70 to check the positions of the reference mark and the alignment mark on the transfer substrate S' and adjust the alignment of the mask 10 so that the alignment mark moves to the position of the reference mark.

The second alignment monitoring unit 80 may be a beam profile camera. The second alignment monitoring unit 80 may be movably provided below the substrate S. The second alignment monitoring unit 80 may capture a focal image of the pattern beam L' that has passed through the transfer substrate S' and generate it as a pattern beam image. The second alignment monitoring unit 80 may check the shape and characteristics of the focal point of the pattern beam L' irradiated onto the transfer substrate S'. Here, the characteristics of the pattern beam L' may include the energy profile and contrast of the focal point of the pattern beam L'. In this case, the energy density and uniformity of the pattern beam L' may be checked from the energy profile, and the sharpness may be checked from the contrast of the pattern beam L'.

The second alignment adjustment unit 90 may control the mask support unit 20 to change the position and gradient of the mask 10 in the traveling direction of the line beam L so that the characteristics of the pattern beam collected from the focal images of the multiple pattern beams L' that have passed through the transfer substrate S' from above to below match the target characteristics. For this purpose, the second alignment adjustment unit 90 may receive a pattern beam image from the second alignment monitoring unit 80, and may control the mask support unit 20 to adjust the alignment of the mask 10 so that at least one of the energy profile and contrast of the pattern beam confirmed from the pattern beam image matches at least one of the target energy profile and target contrast.

The second alignment monitoring unit 80 and the second alignment adjustment unit 90 are used to check how the pattern beam L' is irradiated onto the transfer substrate S', and the position of the mask 10 can be secondarily aligned with respect to the transfer substrate S' by adjusting the alignment of the mask 10 so that the energy profile of the pattern beam matches the target energy profile and the contrast of the pattern beam matches the target contrast. This makes it possible to prevent distortion of the pattern beam L'.

If the position of the mask 10 relative to the transfer substrate S' is aligned, the pattern beam L' can be accurately irradiated onto the adhesive surface between the micro LED chip 1 attached to the transfer substrate S' and the transfer substrate S', and the micro LED chip 1 can be smoothly detached from the transfer substrate S' and accurately dropped onto the desired position on the substrate S.

As described above, the chip transfer device according to an embodiment of the present invention can transfer multiple chips simultaneously to a specified position on a transfer substrate using a mask on which a pattern is formed.

In other words, by using a mask on which a pattern is formed, it becomes possible to transfer the micro LED chips on a pattern-by-pattern basis.

In addition, the chip transfer device according to an embodiment of the present invention can transfer micro LED chips of multiple sizes to a predetermined position on a transfer substrate using a mask on which multiple patterns are formed. More specifically, according to an embodiment of the present invention, a single mask on which multiple different patterns are formed can be used to easily transfer a micro LED chip of a desired size from among multiple sizes to a predetermined position on a transfer substrate.

In other words, even if the production model number is changed and the size of the micro LED chip is changed, there is no need to replace the mask. By simply moving the mask to replace the pattern through which the laser line beam passes, the size, shape and spacing of the multiple laser pattern beams that have passed through the pattern can be adjusted to match the changed size of the micro LED chips and irradiated onto the bonding surface between the multiple micro LED chips and the transfer substrate, so that micro LED chips of various sizes can be easily transferred to a specified position on the transfer substrate.

As a result, it is possible to reduce the time required for mask replacement and shorten the process time, reduce the burden on workers due to mask replacement, and fundamentally prevent alignment problems that may occur when replacing the mask, ensuring stable laser beam quality. This makes it possible to improve the productivity of the micro LED chip transfer process.

Figure 8 is a flow chart of a chip transfer method according to an embodiment of the present invention.

The following describes a chip transfer method according to an embodiment of the present invention.

The chip transfer method according to an embodiment of the present invention includes the steps of providing a transfer substrate S' on a transfer substrate (hereinafter referred to as substrate S) on which multiple chips, for example multiple micro LED chips 1, are provided; emitting a line beam L; shaping multiple pattern beams L' from the line beam L using a mask 10 provided in the path of the line beam L; irradiating the pattern beam L' onto the transfer substrate S' to separate the multiple micro LED chips 1 from the transfer substrate S'; and placing the multiple chips separated from the transfer substrate S' on the substrate S.

In addition, between the step of providing the transfer substrate S' on the substrate S and the step of emitting the line beam L, a pattern replacement step may be further included in which the position of the mask 10 is changed so that the line beam L passes through a pattern among the multiple patterns P formed on the mask 10 whose size corresponds to each of the multiple micro LED chips 1, and is shaped into a pattern beam L'.

Here, "corresponding sizes" means that the sizes match each other within a predetermined error value. For example, the size (also called "area") of one micro LED chip 1 and the size of one focal point of the pattern beam L' may match each other with a predetermined margin, for example. In this case, the size of the pattern beam may be relatively larger. Therefore, when the pattern beam is irradiated onto the bonding surface between the micro LED chip and the transfer substrate S', the pattern beam can be irradiated evenly from the center to the periphery of the bonding surface.

Furthermore, between the step of emitting the line beam L and the step of separating the micro LED chip 1, the method may further include a step of shaping a marker beam L _M from the line beam L using a mask 10 provided in the path of the line beam L, a step of irradiating the marker beam L _M onto a transfer substrate S', photographing the marker beam L _M on the transfer substrate S' to generate a marker beam image, and a primary alignment step of aligning the position of the mask 10 relative to the transfer substrate S' using the marker beam image. In this case, the step of shaping the marker beam L _M may be performed simultaneously with the step of shaping the pattern beam L'.

More specifically, the procedure for shaping the marker beam L _M and the procedure for shaping the pattern beam L' may be performed simultaneously on the same line in the width direction of the line beam L using the same line beam L.

That is, the marker beam L _M and the pattern beam L' may be simultaneously shaped from the same line beam L. In this case, a portion of the line beam L may be shaped into the marker beam L _M , and the remaining portion of the line beam L may be shaped into the pattern beam L'. That is, the marker beam L _M may be shaped from the peripheral portions on both sides of the line beam L, and the pattern beam L' may be shaped from the remaining portion of the line beam L.

Furthermore, between the primary alignment step and the step of separating the micro LED chip 1, a step of irradiating the pattern beam L' onto the transfer substrate S', photographing the pattern beam L' transmitted through the transfer substrate S' to generate a pattern beam image, and a secondary alignment step of aligning the gradient and distance of the mask 10 relative to the transfer substrate S' using the pattern beam image in order to focus the pattern beam that passes through the mask 10 and is irradiated onto the transfer substrate S' may be included.

The chip transfer method according to the embodiment of the present invention may transfer multiple micro LED chips 1 from a transfer substrate S' to a substrate S. The chip transfer method according to the embodiment of the present invention may also be referred to as a micro LED chip transfer method.

S100: First, referring to FIG. 1, a transfer substrate S' having a plurality of micro LED chips 1 is provided on a substrate S. At this time, the plurality of micro LED chips 1 may be a plurality of micro LED chips 1 manufactured on the transfer substrate S'. Alternatively, a plurality of micro LED chips 1 manufactured on a separate sacrificial substrate may be attached to the transfer substrate S'.

A first and second stage (not shown) facing each other in the vertical direction Y may be prepared, the transfer substrate S' may be supported on the lower surface of the first stage, and the substrate S may be placed on the upper surface of the second stage. At this time, the first and second stages may be moved and rotated in multiple directions using first and second drive units (not shown) to align the transfer substrate S' and the substrate S in the vertical direction Y.

At this time, the method for aligning the transfer substrate S' and the substrate S in the vertical direction Y can be changed in various ways. The alignment of the transfer substrate S' and the substrate S is sometimes referred to as a substrate alignment procedure.

S200: Next, the position of the mask 10 is changed to replace the pattern so that the line beam L can pass through a pattern of the multiple patterns P formed on the mask 10 that matches the size of the multiple micro LED chips 1 and be shaped into a pattern beam L'.

Figure 3 is a process flow diagram of the transfer process of the micro LED chip, showing how the line beam L is passed through the pattern formed in the third row r3. Also, Figure 4 is a process flow diagram of the transfer process of the micro LED chip, showing how the mask 10 is moved to pass the line beam L through the pattern formed in the first row r1.

Referring to Figures 3 and 4, the mask 10 is moved in the vertical direction Y so that the line beam L passes through one of the multiple row patterns P. At this time, the alignment of the mask 10 with respect to the transfer substrate S' may become misaligned.

S300: Emit a line beam L toward the transfer substrate S'. The line beam L may be emitted from the laser light source unit 30 toward the transfer substrate S' and irradiated onto the transfer substrate S' via a mask 10 and a reflecting mirror unit 40 placed on the path between the laser light source unit 30 and the transfer substrate S'.

S410: A marker beam L _M is shaped from the line beam L using a mask 10 provided on the path of the line beam L. For example, the line beam L is passed through a pair of alignment markers formed on both sides of a pattern whose size matches that of the multiple micro LED chips 1, among a plurality of alignment markers M formed on both sides of a plurality of patterns P, to form a pair of marker beams L _M on both sides of the pattern beam L'. The pair of marker beams L _M may be shaped into the shape of the alignment marker, for example, a cross shape, while passing through the pair of alignment markers, and proceed in the forward/backward direction Z toward the reflection mirror unit 40.

S420: Next, the marker beam L _M is irradiated onto the transfer substrate S', and the marker beam L _M on the transfer substrate S' is photographed to generate a marker beam image. That is, a pair of marker beams L M traveling in the forward and backward directions _Z toward the reflection mirror unit 40 are reflected by the reflection mirror unit 40 and travel to the transfer substrate S', and a pair of alignment marks formed on the transfer substrate S' by the pair of marker beams L _M irradiated onto the transfer substrate S' from the upper side to the lower side of the transfer substrate S' are photographed by the first alignment monitoring unit 60. At this time, a reference mark displayed in advance on the transfer substrate S' may be photographed together with the marker beam image. Alternatively, the reference mark may be inserted into the _image of the alignment mark, using the coordinates (0, 0) of the reference mark displayed on the transfer substrate S' corresponding to the marker beam L M as a reference.

Figure 5 is a process flow diagram of the micro LED chip transfer process showing how the position and gradient of the mask 10 are adjusted during the primary alignment of the mask 10.

S430: Next, the position of the mask 10 relative to the transfer substrate S' is primarily aligned using the marker beam image. Specifically, the offset (Δx, Δy, Δθ) of the alignment mark relative to the reference mark is calculated from the marker beam image input from the first alignment monitoring unit 60 to the first alignment adjustment unit 70, and the first alignment monitoring unit 60 controls the mask support unit 20 to move and rotate the mask 10 by an amount corresponding to the above-mentioned offset in the left-right direction X and the up-down direction Y, which are directions intersecting with the traveling direction of the line beam L, so that the alignment mark on the transfer substrate S' can be aligned with the reference mark, thereby adjusting the position and gradient of the mask 10 (see Figures 4 and 5). Here, the gradient refers to the gradient or rotation angle of the mask 10 relative to the X-Z plane.

Next, the above-mentioned procedure of generating a marker beam image and the primary alignment procedure may be repeated so that the alignment marks on the transfer substrate S' coincide with the reference marks. These procedures allow the primary alignment of the mask 10 to be completed, and the marker beams L _M can be irradiated at desired positions on the transfer substrate S', so that the pattern beams L' located between the marker beams L _M can also be accurately irradiated at desired positions on the transfer substrate S'.

S510: A mask 10 provided on the path of the line beam L is used to shape a plurality of pattern beams L' from the line beam L. At this time, this procedure may be performed in parallel with the above-mentioned procedure of shaping the marker beam L _M from the line beam L. For example, the line beam L is emitted from the laser light source unit 30 to the mask 10, and is shaped into the pattern beam L' while passing through the mask 10.

Figure 6 is a process flow diagram of the micro LED chip transfer process, showing how the second alignment monitoring unit 80 captures a focused image of the pattern beam L' that has passed through the transfer substrate S' while scanning the transfer substrate S'.

S520: Next, the pattern beam L' is irradiated onto the transfer substrate S, and the pattern beam L' that has passed through the transfer substrate S is photographed to generate a pattern beam image. That is, the pattern beam L' that has passed through the mask 10 is caused to travel to the reflecting mirror unit 40, where it is reflected and irradiated onto the transfer substrate S'. Then, the second alignment monitoring unit 80 photographs the pattern beam L' that has passed through the transfer substrate S' and has a focus formed on the bonding surface between the transfer substrate S' and the micro LED chip 1, to generate a pattern beam image (see FIG. 6).

At this time, the transfer substrate S' is scanned from the top to the bottom along the direction in which the multiple pattern beams L' that have passed through the transfer substrate S' are aligned, and a focused image of the multiple pattern beams is captured. This procedure is performed between the primary alignment procedure and the procedure of separating the multiple micro LED chips. In other words, the pattern beam L' that has passed through the mask 10 after the primary alignment is completed is captured to generate a pattern beam image.

Figure 7 is a process flow diagram of the micro LED chip transfer process showing how the position and gradient of the mask 10 are adjusted during the secondary alignment of the mask 10.

S530: Next, using the second alignment adjustment unit 90, the gradient and distance of the mask 10 relative to the transfer substrate S' for focusing the pattern beam L' irradiated onto the transfer substrate S' is secondarily aligned using the pattern beam image. That is, the characteristics of the pattern beam are collected from the focus image captured in the second alignment monitoring unit 80. The characteristics of the pattern beam collected from the focus image may include at least one of the energy profile and contrast of the pattern beam. Next, using the second alignment adjustment unit 90, the collected characteristics are compared with the target characteristics, and the mask support unit 20 is controlled to adjust the position and gradient of the mask 10 in the traveling direction of the line beam L, for example, in the forward/backward direction Z, so that the collected characteristics match the target characteristics. At this time, the position refers to the position relative to the forward/backward direction Z, and the gradient refers to the gradient relative to the X-Y plane.

At this time, the four corners of the mask 10 at the top, bottom, left, and right may be moved in the forward and backward direction Z by different distances ΔZ1 to ΔZ4, or may be moved by the same distance (see FIG. 7). For example, pulling or pushing the mask 10 in the forward and backward direction Z toward the laser light source unit 30 makes the focus of the pattern beam L' clearer, and at this time, the energy profile can increase or decrease depending on the direction of pulling or pushing to have the desired value.

By using this procedure, the disturbance of the focal image of the pattern beam L' can be corrected, and the procedure for generating the pattern beam image and the secondary alignment procedure described above can be repeated so that the disturbance of the focal image can be corrected to a desired level. Thus, the alignment between the mask 10 and the transfer substrate S' can be completed.

S600: Next, the pattern beam L' shaped while passing through the mask 10 for which the primary and secondary alignments have been completed is irradiated onto the transfer substrate S', and thermal energy is applied to the bonding surface between the transfer substrate S' and the micro LED chip 1, and the multiple micro LED chips 1 are separated from the transfer substrate S'. Specifically, the multiple micro LED chips 1 to be separated from the transfer substrate S' may be irradiated simultaneously with multiple pattern beams while corresponding to each of them. Here, "irradiating while corresponding" means irradiating one micro LED chip 1 with one pattern beam. In this procedure, multiple micro LED chips 1 can be transferred collectively in pattern units onto the substrate S, i.e., the transfer substrate S.

At this time, the mask 10 and the transfer substrate S' are aligned, and the transfer substrate S' and the substrate S are aligned, so that the multiple micro LED chips 1 can be smoothly detached from the transfer substrate S', and the micro LED chips 1 can be placed in accurate positions on the substrate S in the procedure described below.

Next, the multiple micro LED chips 1 detached from the transfer substrate S' are placed with precision at desired positions on the substrate S. At this time, the multiple micro LED chips 1 are dropped below the transfer substrate S' using their own weight as they are detached from the transfer substrate S'. In this procedure, the micro LED chips 1 can be transferred to the substrate S.

At this time, the substrate S may be provided with a thin film layer (not shown) of a bonding material on its upper surface so that the bonded portion of the substrate S and the bonded portion of the substrate of the micro LED chip 1 can be electrically connected while being bonded together.

The thin film layer of the bonding material may be an anisotropically conductive film (ACF) layer. The thin film layer of the bonding material may have a large number of conductive particles dispersed therein and may have a certain adhesiveness. The thin film layer of the bonding material may also be called a conductive material layer or an anisotropically conductive film.

The procedure of separating the chips while scanning the pattern beam L' back and forth along the transfer substrate S' and the procedure of transferring the separated chips to the transfer substrate are repeated until all of the micro LED chips 1 have been separated from the transfer substrate S' to the substrate S and transferred. After that, the next transfer substrate S' may be loaded onto the first stage to perform the next transfer process.

Next, after multiple micro LED chips 1 are transferred to all desired positions on a substrate S, for example, a transfer substrate S, to complete the formation of pixels, the substrate S may be transported to a next process location for carrying out the subsequent process.

The subsequent process may be, for example, a process of bonding the micro LED chip 1 to a thin film layer of a bonding material disposed on the substrate S by applying heat to the bonding surface between the micro LED chip 1 transferred to the substrate S using a laser beam, thereby electrically connecting them.

As described above, in the chip transfer process to which the chip transfer method and device according to the embodiment of the present invention are applied, even if the production model number is changed and the size of the micro LED chip 1 on the transfer substrate S' is different, the mask 10 can be moved to change only the pattern position without replacing the mask 10.

Specifically, the size of the micro LED chips that make up the pixels of a micro LED display device may differ depending on the production model number. Therefore, even if the production model number of the micro LED display device to be produced in the process equipment is changed, the mask 10 can be moved to change only the pattern position without replacing the mask 10.

In other words, according to an embodiment of the present invention, even if the production model number is changed, there is no need to replace the mask 10, so the worker stops the process equipment and replaces the existing mask with a new mask on which a pattern matching the size of the changed micro LED chip is formed, and then there is no need to adjust the size, shape, and spacing of the laser pattern beam. This can shorten the overall process time.

In addition, according to an embodiment of the present invention, by performing primary and secondary alignment in stages after replacing the pattern, stable laser quality can be ensured. Therefore, the productivity of the transfer process for transferring the micro LED chip can be uniformly improved.

Furthermore, when the micro LED chips 1 are to be separated from the transfer substrate S', the laser line beam is passed through the pattern P of the mask 10 to process it into multiple laser pattern beams spaced apart from each other, and the multiple processed laser pattern beams L' are irradiated onto the bonding surface between the multiple micro LED chips and the transfer substrate, so that the multiple micro LED chips can be separated all at once, and the multiple micro LED chips 1 can be transferred all at once over a wide area on the transfer substrate S. This increases the process speed.

The above-mentioned embodiments of the present invention are for the purpose of explaining the present invention, and are not intended to limit the present invention. It should be noted that the configurations and methods disclosed in the above-mentioned embodiments of the present invention may be modified into various forms by combining or intersecting with each other, and these modifications may also be considered to fall within the scope of the present invention. In other words, the present invention may be embodied in various different forms within the scope of the claims and the technical ideas equivalent thereto, and those skilled in the art to which the present invention pertains should be able to understand that various embodiments are possible within the scope of the technical ideas of the present invention.

1: Micro LED chip S: Transferred substrate S': Transfer substrate 10: Mask 20: Mask support section 30: Laser light source section 50: Pattern replacement section 60: First alignment monitoring section 80: Second alignment monitoring section

Claims (16)

providing a transfer substrate having a plurality of chips on a transfer substrate;
a procedure for emitting a line beam;
shaping a marker beam from the line beam using a mask disposed in the path of the line beam;
A step of irradiating the marker beam onto the transfer substrate and capturing an image of the marker beam on the transfer substrate to generate a marker beam image;
a primary alignment step in which the marker beam image is used to align the position of the mask relative to the transfer substrate;
shaping a plurality of pattern beams from the line beam using the mask provided in a path of the line beam;
irradiating the pattern beam onto the transfer substrate to separate a plurality of chips from the transfer substrate;
placing the plurality of chips detached from the transfer substrate on the transfer substrate;
A chip transfer method comprising: The step of separating the plurality of chips includes:
2. The chip transfer method according to claim 1, further comprising the step of irradiating the plurality of pattern beams corresponding to the plurality of chips to be separated from the transfer substrate, respectively. The chip transfer method according to claim 2, further comprising a pattern replacement step of changing the position of the mask so that the line beam can be passed through a pattern of the multiple patterns formed on the mask, the pattern beam being shaped into a pattern having a size corresponding to each of the multiple chips. 2. The chip transfer method of claim 1, wherein the step of shaping the pattern beam and the step of shaping the marker beam are performed simultaneously using the same line beam, but the marker beam is shaped from a portion of the line beam and the pattern beam is shaped from the remaining portion . a step of irradiating the transfer substrate with the pattern beam and capturing an image of the pattern beam transmitted through the transfer substrate to generate a pattern beam image;
a secondary alignment step of aligning the slope and distance of the mask with respect to the transfer substrate for focusing the pattern beam through the mask and onto the transfer substrate using the pattern beam image;
The chip transfer method according to claim 1 , comprising: The step of shaping the marker beam includes:
4. The chip transfer method according to claim 3, further comprising the step of passing the line beam through a pair of alignment markers formed on both sides of a pattern whose size matches that of the plurality of chips, among a plurality of alignment markers formed on both sides of the plurality of patterns, to form a pair of the marker beams on both sides of the pattern beam . The step of generating the marker beam image includes:
a step of photographing a pair of alignment marks formed on the transfer substrate by the pair of marker beams irradiated onto the transfer substrate from above to below;
a step of inserting the reference mark into an image of the alignment mark using the coordinates of the reference mark displayed on the transfer substrate so as to correspond to the marker beam;
The chip transfer method according to claim 6 , comprising: The primary alignment procedure comprises:
calculating an offset of the alignment mark relative to the fiducial mark from the marker beam image;
adjusting a position and a gradient of the mask in a direction intersecting a traveling direction of the line beam by an amount corresponding to the offset so that the alignment mark can be aligned with the reference mark;
The chip transfer method according to claim 7 , comprising: The step of generating the pattern beam image includes:
The chip transfer method according to claim 5, further comprising the step of capturing a focused image of the multiple pattern beams while scanning the transfer substrate from above to below along a direction in which the multiple pattern beams that have passed through the transfer substrate are arranged. The secondary alignment procedure comprises:
a step of collecting characteristics of the plurality of pattern beams from the focused image and comparing the collected characteristics with a reference characteristic;
adjusting a position and a gradient of the mask in a direction of travel of the line beam so that the collected characteristics match the target characteristics;
The chip transfer method according to claim 9 , comprising: A chip transfer apparatus that transfers a plurality of chips from a transfer substrate to a transferee substrate,
a mask on which a pattern is formed so that a line beam can be shaped into a plurality of pattern beams and irradiated onto a transfer substrate, and an alignment marker is formed so that the line beam can be shaped into a marker beam and irradiated onto the transfer substrate ;
a mask support section that supports the mask so as to be movable and rotatable;
a laser light source unit that emits the line beam toward the mask so as to transfer a plurality of chips;
a first alignment monitoring unit that captures the marker beam irradiated onto the transfer substrate to generate a marker beam image;
a first alignment adjustment unit that controls the mask support unit to change a position and a gradient of the mask in a direction intersecting a traveling direction of the line beam so that a pair of alignment marks formed on the transfer substrate by the pair of marker beams irradiated from above to below the transfer substrate coincide with a reference mark displayed on the transfer substrate so as to correspond to the marker beams;
A chip transfer device comprising: A plurality of patterns having different sizes are formed on the mask,
The chip transfer device according to claim 11 , wherein any one of the plurality of patterns has a size corresponding to each of the plurality of chips. The chip transfer apparatus according to claim 12, further comprising a pattern replacement unit that controls the mask support unit to change the position of the mask so that the line beam passes through a pattern among the plurality of patterns that has a size matching that of the plurality of chips attached to the transfer substrate. The chip transfer device described in claim 12, wherein each of the multiple patterns has a multiple number of pattern holes, and the pattern holes arranged on the same line in the width direction of the line beam have similar shapes, sizes and arrangements, and the pattern holes arranged in a direction intersecting the width direction of the line beam have different shapes, sizes and arrangements. the alignment markers are formed on both sides of the patterns in a width direction of the line beam,
The alignment markers are aligned on the same line as the patterns in a width direction of the line beam,
15. The chip transfer apparatus according to claim 13 or 14, wherein the plurality of pattern beams that have passed through a pattern whose size matches the plurality of micro LED chips and the pair of marker beams that have passed through a pair of align markers located on both sides of the pattern whose size matches the plurality of micro LED chips are simultaneously irradiated onto the transfer substrate. a second alignment monitoring unit that captures focal images of the plurality of pattern beams that have passed through the transfer substrate and generates them as pattern beam images;
a second alignment adjustment unit that controls the mask support unit to change a position and a gradient of the mask in a traveling direction of the line beam so that characteristics of the plurality of pattern beams collected from focal images of the plurality of pattern beams that have passed through the transfer substrate from above to below the transfer substrate match target characteristics;
The chip transfer device according to claim 15 .