JP6932676B2 - Transfer method, manufacturing method of image display device using this, and transfer device - Google Patents

Description

The present invention relates to a transfer method for transferring a chip component to a substrate, a method for manufacturing an image display device using the transfer method, and a transfer device.

Semiconductor chips are becoming smaller due to advances in microfabrication technology, and LED chips are becoming smaller due to improved luminous efficiency of LEDs. Therefore, a large number of chip components such as semiconductor chips and LED chips can be densely formed on one wafer substrate.

In recent years, the chip component C densely formed and diced on the wafer substrate W as shown in FIG. 15A is rearranged on the wiring substrate S at a predetermined interval and mounted at high speed and with high accuracy (FIG. 15A). c)) There are uses. For example, in the manufacture of micro LED displays, which are attracting attention as image display devices, it is necessary to mount one million or more LED chips at predetermined positions on a TFT substrate at intervals.

Here, an enlarged view of FIG. 15B showing a cross section of the wafer substrate W and FIG. 15D showing a cross section of the wiring board S is shown in FIGS. 16A and 16B, but the chip component C is shown. In order to reliably bond the bump electrode B to each electrode (not shown) of the wiring board S, an accuracy with a margin of error of about several μm or less is required.

Therefore, a process of mounting the chip components C densely formed on the wafer substrate W as shown in FIG. 15A on the wiring board S at predetermined intervals as shown in FIG. 15C with high accuracy is performed. Various studies have been conducted.

In particular, many studies have been made on the laser lift-off method (for example, Patent Document 1).

FIG. 17 shows an example in which the chip component C is transferred and arranged from the wafer substrate W to the wiring substrate S by the laser lift-off method. FIG. 17A shows a state in which the leftmost chip component C is irradiated with the laser beam L and transferred to the wiring board S. Here, the leftmost chip component C is aligned with the upper portion of the wiring board S at a predetermined position. Further, the wavelength of the laser beam L in FIG. 17A is selected from a range suitable for peeling the chip component C from the wafer W. For example, if a wavelength absorbed by the material of the chip component is used, the chip component C is peeled from the wafer substrate W by the gas generated by the decomposition of the material as the temperature rises.

FIG. 17B shows a state in which the leftmost chip component C peeled off from the wafer substrate W by irradiation with the laser beam L is transferred to the wiring substrate S. Here, since the leftmost chip component C is transferred directly below, it is arranged at a predetermined position on the wiring board S. If the moving distance d directly below the chip component C due to transfer is made larger than the total height of the chip component C and the bump B, even if the chip component C is transferred to the wiring board S, it interferes. It is possible to move the wafer substrate W in the horizontal direction without doing so.

FIG. 17C shows a state in which the laser beam L is irradiated after the predetermined positions of the chip component C and the wiring board S to be transferred next are arranged directly under the laser beam L. By this laser irradiation, the next chip component C is transferred and arranged at a predetermined position on the wiring board S at a distance from the chip component C previously transferred and arranged.

After that, by arranging the chip component C to be transferred and the predetermined position of the wiring board S (the position where the chip component C should be mounted) at any time directly under the laser beam L and transferring the chip component C, FIG. The chip component C can be transferred and arranged on the wiring board S as shown in c). When the chip component C is arranged on the wafer substrate W and the integral multiple of the arrangement pitch matches the arrangement position of the wiring board S, the irradiation position of the laser beam L is changed without moving the wafer substrate W. Can also be transferred.

However, in order to separate the chip component C from the wafer substrate W as shown in FIGS. 17A to 17B, a large amount of energy due to the laser beam L is applied to the chip component C. Therefore, the chip component C reaches the wiring board S in an accelerated state even during the moving distance d shown in FIG. 17B. On the other hand, the electrode portion of the wiring board S is made of metal, and the chip component C may be damaged as shown in FIG. 18 due to the impact when the bump electrode B of the accelerated chip component C comes into contact with the metal electrode. In order to alleviate such an impact, a thermosetting adhesive (or a conductive paste, ACF, etc.) (which is uncured used for sealing) is coated on the bump of the chip component C or the electrode of the wiring board C. Although it is possible, the coating thickness is 5 μm or less, which is insufficient to alleviate the impact.

As described above, since the impact applied to the chip component C is large in the direct transfer from the wafer substrate W to the wiring substrate S, a transfer method using a transfer substrate is generally used.

Japanese Unexamined Patent Publication No. 2010-161221

In the transfer method using a transfer substrate, as shown in FIG. 19A, first, the first transfer substrate 1 is brought into close contact with the chip component C of the wafer substrate W, and the chip component C is peeled off by laser light or the like to form the first transfer substrate. Transfer to the transfer substrate 1. The first transfer substrate 1 has a configuration in which the base substrate 10 and the adhesive layer 11 are provided on the side of the base substrate 10 that holds the chip component C. Here, since the chip component C is transferred in close contact with the first transfer substrate, it is transferred onto the adhesive layer 11 of the first transfer substrate 1 without being accelerated.

By the way, as shown in FIG. 19B, since the bump B of the chip component C is in close contact with the first transfer board 1, even if the chip component C is transferred from this state to the wiring board S, the bump B is still formed. It cannot be brought into contact with the electrodes of the wiring board S. Therefore, it is necessary to transfer the chip component C of the first transfer board 1 to the second transfer board 2 again. At this time, the chips are often transferred to the second transfer substrate 2 by widening the interval between the chip components C. Therefore, the laser lift-off method is mainly used for the transfer from the first transfer substrate 1 to the second transfer substrate 2. Further, similarly to the first transfer board 1, the second transfer board 2 also has a structure in which the base board 20 and the adhesive layer 21 are provided on the side of the base board 20 that holds the chip component C.

FIG. 19C shows the leftmost chip component C from a state in which the surface on which the chip component C of the first transfer board 1 is arranged and the adhesive layer 21 of the second transfer board 2 face each other with a gap. From this state showing a state in which the laser beam L is irradiated and transferred to the second transfer substrate 2, the chip component C irradiated with the laser beam L is transferred to the second transfer substrate 2 (FIG. 20 (d)). )).

After that, the relative positions of the first transfer board 1 and the second transfer board 2 in the plane direction are changed, and the chip component C is transferred to a predetermined position of the second transfer board (FIGS. 20 (e) and 20 (f)). This completes the transfer of the chip component C to the second transfer board 2.

By the way, the force for peeling the chip component C held on the first transfer substrate 1 via the adhesive layer 11 is smaller than the force for peeling from the wafer substrate W. Therefore, the damage of the chip component as shown in FIG. 18 is reduced by the transfer from the first transfer board 1 to the second transfer board 2. However, even in the laser lift-off method in which chip components are transferred from the first transfer board 1 to the second transfer board 2, damage may occur. For example, when the chip component C is irradiated with the laser beam L, as shown in FIG. 21A, when the spot diameter is small, the peripheral portion of the chip component C is peeled off from the adhesive layer 11 of the first transfer substrate 1. The laser intensity required for this is high. Therefore, the chip component C peeled off from the adhesive layer 11 may reach the adhesive layer 21 of the second transfer substrate 2 with a large amount of kinetic energy and be damaged (FIG. 21 (b)). In order to suppress this, the impact force can be alleviated by devising the adhesive layer 21, but it is difficult to completely eliminate the damage.

On the other hand, as shown in FIG. 22A, by widening the spot diameter of the laser beam L, the peripheral portion of the chip component C can be easily peeled off, and damage when reaching the adhesive layer 21 can be prevented. However, if the spot diameter becomes too wide, the laser beam L is also irradiated to the chip component C adjacent to the transfer target, which may cause partial peeling as shown in FIG. 22B, which is not preferable. In addition, high accuracy is required for the alignment of laser irradiation.

The present invention has been made in view of the above problems, and when the chip component held by the transfer substrate is transferred to the transfer destination substrate by the laser lift-off method, only the transfer target chip is reliably transferred without being damaged. It provides a transfer method which can be performed and a method for manufacturing an image display device using the transfer method.

In order to solve the above problems, the invention according to claim 1 is a transfer method for transferring a chip component held on a transfer substrate via a photocurable adhesive layer to a transfer destination substrate.
After the exposure step of pattern-exposing the adhesive layer with light having a wavelength that cures the adhesive layer to partially reduce the adhesive force of the adhesive layer, and the exposure step, the chip component is subjected to the laser lift-off method. This is a transfer method including a laser lift-off step of transferring to a transfer destination substrate.

The invention according to claim 2 is the transfer method according to claim 1.
This is a transfer method in which a light-shielding region that is shielded from light during the exposure step is provided at least within a laser irradiation range for irradiating a laser in the laser lift-off step.

The invention according to claim 3 is the transfer method according to claim 2, wherein the light-shielding region provided in the laser irradiation range corresponds to a range of 5 μm square or more and 50 μm square or less. ..

The invention according to claim 4 is the transfer method according to claim 1.
The laser beam used in the laser lift-off step is a Gaussian beam, which is a transfer method in which the laser irradiation range is larger than the size of the chip component.

The invention according to claim 5 uses an LED chip as the chip component.
A method for manufacturing an image display device comprising a step of transferring the LED chip transferred to the transfer destination substrate from the transfer destination substrate to the TFT substrate by the transfer method according to any one of claims 1 to 4. be.

The invention according to claim 6 uses an LED chip as the chip component and a TFT substrate as the transfer destination substrate.
A method for manufacturing an image display device, which comprises a step of transferring the LED chip to the TFT substrate by the transfer method according to any one of claims 1 to 4.

The invention according to claim 7 is a transfer device that transfers a chip component held on a transfer substrate to a transfer destination substrate via a photocurable adhesive layer.
A transfer substrate holding means for holding the transfer substrate, and a light source for irradiating the adhesive layer with light having a wavelength that cures the adhesive layer from the opposite side of the chip holding surface of the transfer substrate.
A mask arrangement having a function of arranging a mask that partially blocks the light between the transfer board and the light source to align the chip components and a function of retracting the mask from the transfer board. It is a transfer device including means and a laser light source that irradiates the chip component with laser light from the opposite side of the chip holding surface of the transfer substrate in a state where the mask is retracted from the transfer substrate.

The invention according to claim 8 is a transfer device that transfers a chip component held on a transfer substrate to a transfer destination substrate via a photocurable adhesive layer.
A transfer substrate holding means for holding said transfer substrate, said portion of the adhesive force from the opposite side was irradiated while scanning the laser beam having a wavelength of curing the adhesive layer and the adhesive layer of the chip holding surface before Symbol transfer substrate It is a transfer device including a laser light source having a function of substantially lowering the chip components and a function of irradiating a laser beam for transferring the chip component from the transfer substrate to the transfer destination substrate by a laser lift-off method.

By using the transfer method of the present invention, when the chip component is transferred from the transfer substrate to the transfer destination substrate by the laser lift-off method, the power of the laser beam is not excessive and only the chip to be transferred is damaged. It can be reliably transferred without any trouble, and the chip components can be reliably transferred and mounted on the wiring board. Therefore, it is also suitable for manufacturing an image display device that transfers millions of LED chips to a TFT substrate.

It is a figure which shows the structure of the transfer substrate (first transfer substrate) which concerns on embodiment of this invention. The photosensitive layer of the adhesive layer of the first transfer substrate according to the embodiment of the present invention will be described. In the state of (a) partial exposure using a photo and a mask, (b) the exposed portion is cured and adhered. It is a figure which shows the state which the sex is deteriorated. According to the embodiment of the present invention, (a) a diagram showing a chip component held and diced on a wafer substrate, and (b) a diagram showing a step of transferring the chip component from the wafer substrate to the first transfer substrate. (C) It is a figure which shows the state which the chip component was transferred to the 1st transfer substrate. According to the embodiment of the present invention, (a) a first transfer substrate in which a chip component is held by an adhesive layer, (b) a state in which the adhesive layer is pattern-exposed, and (c) the adhesiveness of the adhesive layer is obtained in the exposed portion. It is a figure explaining the state which is lowered. According to the embodiment of the present invention, (a) a state in which the first transfer substrate 1 and the second transfer substrate 2 in which the adhesiveness of the adhesive layer holding the chip component is partially reduced are opposed to each other, and (b) the second transfer It is a figure which shows the state which irradiates the chip component of the 1st transfer board which faces a substrate with a laser beam, and (c) is the figure which shows the state which the chip component is transferred to the 2nd transfer board. The operation of the transfer apparatus according to the embodiment of the present invention is described, and is (a) a diagram showing an apparatus configuration, and (b) a diagram showing a preparatory stage of an exposure process. The operation of the transfer apparatus according to the embodiment of the present invention is described, and is a diagram showing (c) an exposure process and (d) a diagram showing a laser lift-off process. It is a figure which shows the state which irradiates the laser beam of the Gaussian beam in the laser lift-off process according to the embodiment of this invention. In the figure which shows the state which irradiates the laser beam of the Gaussian beam in the laser lift-off process, it is the figure which shows the example which the size of a chip part is larger than the laser beam irradiation range. The present invention shows an example in which the present invention is applied when the size of a chip component is larger than the laser beam irradiation range even when the laser beam of the Gaussian beam is irradiated. (A) It is a figure which shows the state which irradiates the chip component of the 1st transfer board with a laser beam which face | facet the 2nd transfer board, and (b) shows the state which the chip component was transferred to the 2nd transfer board. It is a figure. It is a figure which shows (a) the surface shape of a chip part and an adhesive part, and (b) is a figure explaining the specific shape of the low-adhesive part, according to the embodiment of this invention. FIG. 5 is a diagram showing an example in which an adhesive portion is left separately from the laser light irradiation range of the laser lift-off step according to the embodiment of the present invention. An embodiment in which the present invention is applied to a second transfer substrate will be described, and is a diagram showing (a) a configuration of a second transfer substrate having a photocurable adhesive layer, and (b) the same adhesive layer and a base substrate. It is a figure which shows the structure which had the shock absorbing layer between. Another embodiment of the present invention will be described, wherein (a) a state in which the adhesive layer is exposed by irradiating light from the chip component side is shown, and (b) a low adhesive layer is partially formed by the same exposure. It is a figure which shows the state which was done. (A) Top view showing a wafer substrate and chip parts, (b) Cross-sectional view, (c) Top view showing a wiring board and chip parts, and (d) Cross-sectional view. (A) is an enlarged view of a cross section of a wafer substrate and a chip component, and (b) is an enlarged view of a cross section in which a chip component is mounted on a wiring board. The process of directly transferring the chip component from the wafer substrate to the wiring board will be described. (A) The process of peeling the chip component from the wafer substrate, (b) The state in which the chip component is transferred to the wiring board (c) The wafer substrate It is a figure which shows the process of peeling off the next chip component from 1 (d), and (d) the state where the next chip component is transferred to the wiring board. It is a figure explaining how the chip component peeled off from a wafer substrate is damaged by the impact by a collision with a wiring board. The transfer process of the chip component by the conventional laser lift-off method is described, and is a diagram showing (a) a process of transferring the chip component from the wafer substrate to the first transfer substrate, and (b) the chip component is the first transfer. It shows the state which was transferred to the substrate, and is (c) the figure which shows the state which irradiates the chip component of the 1st transfer substrate with a laser beam which faced with the 2nd transfer substrate. The transfer process of the chip component by the conventional laser lift-off method is described, (d) is a diagram showing a state in which the chip component is transferred to the second transfer substrate, and (e) the next chip of the first transfer substrate. It is a figure which shows the state which irradiates the component with a laser beam, (f) is the figure which shows the state which the next chip component is transferred to the 2nd transfer substrate. In the laser lift method, (a) is a diagram showing a state in which a laser beam having a small spot diameter is applied to a chip component, and (b) is a diagram showing a state in which the chip component after transfer is damaged. In the laser lift method, (a) a diagram showing a state in which a laser beam having a large spot diameter is applied to a chip component, and (b) a diagram showing a state in which a chip component adjacent to a transfer target is partially peeled off. Is.

An embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a first transfer substrate 1 which is a transfer substrate according to an embodiment of the present invention. As shown in FIG. 1, the first transfer substrate 1 has an adhesive layer 11 laminated on the base substrate 10.

The base substrate 10 needs to have translucency with respect to the wavelength of the laser light L used in the laser lift-off method. This is because it is necessary to irradiate the interface between the chip component C and the adhesive layer 11 with the laser beam L.

The adhesive layer 11 is formed of a resin material such as silicone or acrylic, and has photocurability, and is cured by light having a predetermined wavelength to reduce the adhesiveness. That is, as shown in FIG. 2A, when exposed with a photomask PM in a partially shaded state, the adhesive layer of the exposed portion is an optical UV containing a wavelength that cures the adhesive layer 11. No. 11 has a reduced adhesive force and becomes a low adhesive portion 11C (FIG. 2 (b)). Here, the low adhesive portion 11C also includes a non-adhesive case having no adhesiveness. On the other hand, the light-shielded portion maintains the adhesiveness as the adhesive portion 11A. However, the adhesive force of the outer peripheral portion of the adhesive portion 11A may decrease due to the wraparound of light due to diffraction or the like. In the above description, it is assumed that the base substrate 10 transmits light having a wavelength that cures the adhesive layer 11.

Hereinafter, an embodiment using the first transfer substrate 1 having the configuration shown in FIG. 1 in the process of transferring the chip component C on the substrate W to the second transfer substrate 2 is shown in FIGS. 3, 4, and 5. It will be described using.

FIG. 3A is a diagram showing a chip component C formed on the wafer substrate W and diced, and a bump electrode B is formed on each chip component C. The chip components targeted by the present invention are mainly those having a minute size dicing to a side of 100 μm or less, but the present invention is not limited to this.

FIG. 3B describes a step of transferring the chip component C on the wafer substrate W to the first transfer substrate 1, with the first transfer substrate 1 in close contact with the chip component C of the wafer substrate W. It shows a state in which the chip component C is peeled off from the wafer substrate W and transferred to the adhesive layer 11 of the first transfer substrate 1. In the state of FIG. 3B, by heating the chip component C with laser light or the like transmitted through the wafer substrate W, the components constituting the chip component C are decomposed and generated at the interface between the chip component C and the wafer substrate W. The chip component C is peeled off by the gas.

After that, when the wafer substrate W and the first transfer substrate 1 are separated, the chip component C is transferred to the first transfer substrate 1 side and held by the adhesive layer 11 as shown in FIG. 3C.

Next, an exposure step of partially reducing the adhesive force of the adhesive layer 11 on the first transfer substrate 1 (FIG. 4A) to which the chip component C has been transferred will be described.

In the exposure step of the present embodiment, pattern exposure is performed as shown in FIG. 4B with light having a wavelength that cures the adhesive layer 11. That is, a photomask PM having a pattern matching the arrangement of the chip components is arranged on the opposite surface of the surface of the first transfer substrate 1 that holds the chip component C, and an optical UV including a wavelength for curing the adhesive layer 11 is generated. , Photomask PM is used for irradiation and exposure.

By this exposure, as shown in FIG. 4C, the adhesive layer 11 of the portion irradiated with light UV is cured to become a low adhesive portion 11C. On the other hand, the portion shaded by the photomask PM is not cured and maintains the adhesiveness, so that it becomes the adhesive portion 11A (FIG. 4 (c)). Here, it is possible to change the difference in adhesive strength between the low adhesive portion 11C and the adhesive portion 11A depending on the irradiation amount of light UV, and a difference is provided so that the holding of the chip component C is substantially carried by only the adhesive portion 11A. Is preferable. The state in which the adhesive layer 11 of the first transfer board 1 holding the chip component C as shown in FIG. 4C is partially formed as the low adhesive portion 11C is referred to as the chip component transfer board 100.

FIG. 4C shows an example in which the low-adhesive layer 11C is formed by leaving a certain region of the central portion of the chip component C, and the photomask PM that forms the pattern of the low-adhesive portion 11C in this way is It is used for the exposure shown in FIG. 4 (b).

Next, a laser lift-off step of transferring the chip component C from the chip component transfer substrate 100 to the second transfer substrate 2 by the laser lift-off method will be described with reference to FIG.

First, as shown in FIG. 5A, the first transfer substrate 1 and the second transfer substrate 2 are arranged in parallel via the spacer 102 so that the chip component C and the adhesive layer 21 face each other. Here, in the spacer 102, even after a part of the chip component C is transferred to the second transfer board 2, the chip component C held by the first transfer board 1 and the chip component C transferred to the second transfer board 2 are present. The height is such that the relative positions of the first transfer board 1 and the second transfer board 2 can be moved in parallel without interfering with each other.

From this state, as shown in FIG. 5B, by irradiating the laser beam L, the light transmitted through the base substrate 10 reaches the interface between the adhesive layer 11 and the chip component C. Here, if the wavelength of the laser beam L is absorbed by the chip component C, a force is applied to the chip component C in the direction of peeling from the adhesive layer 11 due to the gas pressure generated from the chip component C. If the material of the adhesive layer 11 absorbs a specific wavelength and emits gas in an uncured state, the wavelength of the laser beam L may be the wavelength absorbed by the adhesive portion 11A. Further, it is desirable that the irradiation range of the laser beam L is within the surface size of the chip component C to avoid the influence on the adjacent chip component C.

By irradiating the laser beam L as shown in FIG. 5B, a force is applied to the chip component C in the direction away from the adhesive layer 11, but the area of the adhesive portion 11A that substantially holds the chip component C is made appropriate. By doing so, the chip component C can be reliably peeled off from the adhesive layer 11 without applying excessive kinetic energy. Specifically, if the adhesive portion 11A of the adhesive layer 11 is within the irradiation range of the laser beam L, the portion that substantially holds the chip component C and the portion that is peeled off by the laser lift-off method coincide with each other. Therefore, the laser lift-off can be reliably performed with the laser beam L having an appropriate energy. That is, it is possible to prevent the chip parts from being damaged by the laser beam L having excessive energy. Therefore, it is desirable that the light-shielding region shaded by the photomask PM used in the exposure step of FIG. 4B is within the laser irradiation range of the laser lift-off step.

Further, even if the spot diameter of the laser beam L is small, the peripheral portion of the chip component C is not adhesively held, so that the entire chip component C can be easily peeled off. Therefore, it is possible to prevent the chip component C adjacent to the transfer target from being affected by the laser beam L.

As a result, as shown in FIG. 5C, the chip component C can be reliably transferred from the first transfer board 1 to the second transfer board 2 without being damaged.

The adhesive layer 21 of the second transfer substrate 2 shown in FIG. 5C not only has the adhesiveness for holding the chip component C, but also cushions the impact of the chip component C transferred from the first transfer substrate 1. It is desirable to have flexibility as well.

6 and 7 show the configuration and operation of the transfer device 101, which is an example of a device for transferring the chip component C from the first transfer board 1 to the second transfer board 2 in the above steps. ..

FIG. 6A shows the configuration of the transfer device 101, in which the chip component C held by the first transfer substrate 1 which is the transfer substrate via the photocurable adhesive 11 is held by the second transfer destination substrate. An example of transferring to the transfer substrate 2 is shown.

The transfer device 101 includes a transfer destination substrate stage 3, a transfer substrate holding means 4, a mask arranging means 5, a light source 6, a laser light source 7, a slide mechanism 8, and a laser light source slide mechanism 70 as constituent elements.

The transfer destination substrate stage 3 holds the transfer destination substrate, and has a function of holding the second transfer substrate 2 in the present embodiment. The transfer substrate holding means 4 is used to hold the transfer substrate and adjust the spacing and the relative position in the plane direction in a state parallel to the transfer destination substrate. In the present embodiment, the first transfer substrate 1 is used. It has a function to hold. The mask arranging means 5 arranges the photomask PM on the surface of the transfer substrate (first transfer substrate 1 in the present embodiment) in which the chip components are not held. The light source 6 irradiates light UV including a wavelength that cures the adhesive layer 11 from the side where the chip component of the transfer substrate is not held. In FIG. 6A, the light source 6 has a shape of irradiating line-shaped light, but the light source 6 is not limited to this. The laser light source 7 irradiates the chip component C held on the transfer substrate with a spot-like laser beam L, and the chip component C irradiated with the laser beam L is peeled off and transferred to the transfer destination substrate. The slide mechanism 8 has a function of sliding the mask arranging means 5 and the light source 6 linearly (in FIG. 6A, the slide mechanism 8 slides in the Y direction. The laser light source slide mechanism 70 linearly slides the laser light source 7 (FIG. 6A). In 6 (a), it has a function of sliding in the X direction) and also has a function of moving linearly (Y direction) by the slide mechanism.

In the transfer device 101 having the configuration shown in FIG. 6A, when performing the exposure step, the mask arranging means 5 first transfers the photomask PM to the transfer substrate (first transfer substrate 1) as shown in FIG. 6B. After arranging the image in alignment with the above, the light source 6 irradiates light UV as shown in FIG. 7C to perform exposure. In the transfer device 101, since the light source 6 irradiates light UV in a line shape (X direction), the light source 6 moves along the slide mechanism 8 (in the Y direction) to perform surface exposure.

After the exposure step, as shown in FIG. 7D, the mask arranging means 5 retracts the photomask PM from above the transfer substrate, and performs a laser lift-off step of the chip component C by the laser beam L. At the time of laser lift-off, the slide mechanism 8 and the laser light source slide mechanism 70 align the laser light source 7 on each chip and irradiate the chip component C with the laser light L.

In the laser lift-off step, the transfer substrate (first transfer substrate 1) is placed in a predetermined position using the transfer substrate holding means 4 so that the chip component C is transferred to a predetermined position on the transfer destination substrate (second transfer substrate 2). Place in.

The present invention can be realized without the light source 6, the photomask PM, and the mask arranging means 5. That is, if the laser light source 7 can irradiate light having a wavelength that cures the adhesive layer 11, the slide mechanism 8 and the laser light source slide mechanism 70 scan the laser light source 7 to expose the adhesive layer 11 in a predetermined pattern. You may. However, in pattern exposure using the laser light source 7, it is necessary to control the oscillation power so as not to cause the lift-off phenomenon.

By the way, it is described that it is desirable that the irradiation range of the laser beam L is within the surface size of the chip component C, but the present invention is applied even when the irradiation range of the laser beam L is larger than the size of the chip component C. can do. For example, as shown in FIG. 8, even if the irradiation range is the laser beam Lg of the Gaussian beam larger than the size of the chip component C, if the irradiation range does not extend to the adhesive portion 11A of the adjacent chip component C, There is almost no effect on the adjacent chip component C.

Further, as shown in FIG. 9, a large-sized chip component C (hereinafter referred to as chip component CW) for which it was difficult to apply the laser lift-off method even with a laser beam Lg having a wide irradiation range such as a Gaussian beam. The present invention is also valid. That is, even when the laser beam L having an irradiation range not as wide as the laser beam Lg of the Gaussian beam is used, the size of the adhesive portion 11A holding the chip component CW is made appropriate as shown in FIG. 10A. As a result, transfer by the laser lift-off method becomes possible as shown in FIG. 10 (b).

The surface shapes of the chip component CW and the adhesive portion 11A shown in FIG. 10 are as shown in FIG. 11A, and FIG. 11 (a) shows one chip component CW. b). Here, as shown in FIG. 11B, the surface size of the adhesive portion 11A depends on the size of the chip component C (not limited to the chip component CW) and the irradiation range of the laser beam to be irradiated, but is 5 μm square or more. It is desirable that the size is within the size of 50 μm square. As long as it is this size, the shape is not limited and may be circular.

When the size of the chip component CW is large, the adhesive portion 11A may be peeled off from the edge portion only by the adhesive portion 11A that matches the size of the irradiation range of the laser beam L (Lg). Therefore, the light intensity of the wavelength at which the adhesive layer 11 is cured, which is irradiated in the exposure step, may be weakened so that the adhesive strength of the low adhesive portion 11C is slightly strengthened. However, if the area of the low-adhesive portion 11C is larger than that of the adhesive portion 11A, it is difficult to reliably perform the laser lift-off step, and it is also difficult to appropriately control the adhesive force of the low-adhesive portion 11C by the irradiation light intensity. .. Therefore, as shown in FIG. 12, the adhesive portion 11a may be provided in the vicinity of the edge portion of the chip component CW. Here, if the adhesive portion 11a is also too large, it may hinder the chip component CW from being peeled off at the time of laser lift-off, but since it is formed by pattern exposure, it is easy to set an appropriate size and arrangement.

The embodiments described so far are limited to the case where the chip component C held by the first transfer board 1 is transferred to the second transfer board 2 by the laser lift method, but the present invention is held by the second transfer board 2. It is also effective when transferring the chip component C to be transferred to the wiring board S. That is, the second transfer board 2 may be used as the transfer board, and the wiring board S may be used as the transfer destination board. Specifically, in the second transfer substrate 2 composed of the base substrate 20 and the adhesive layer 21 shown in FIG. 13A, the adhesive layer 21 may have the same characteristics as the adhesive layer 11 of the first transfer substrate 1. .. Further, since the second transfer substrate 2 is also required to have shock absorption property, the shock absorption layer 22 may be provided between the base substrate 20 and the adhesive layer 21 in FIG. 13A (FIG. 13 (a). b)). Here, the shock absorbing layer 22 has a shock absorbing property and at least a light transmitting property for transmitting the laser light L, and further has a light transmitting property for transmitting light having a wavelength that cures the adhesive layer 21. Is desirable.

Further, as another embodiment of the present invention, as shown in FIG. 14A, light UV including a wavelength for curing the adhesive layer 11 may be irradiated from the chip component C side. In this case, the photomask is not used, and the light UV passing through the gap between the adjacent chip parts C is reflected or diffracted at the end portion of the chip component C, so that the light UV is reflected or diffracted at the end portion of the chip component C to form a peripheral portion of the chip component as shown in FIG. 14 (b). The adhesive layer 11 facing each other is cured to form the low adhesive layer 11C, and the size of the adhesive portion 11A can be made smaller than that of the chip component C.

As described above, in the present invention, when the chip component C is transferred from the first transfer board 1 to the second transfer board 2 by the laser lift method, or when the chip component C is transferred from the second transfer board 2 to the wiring board S. The chip component C to be transferred can be reliably transferred to the transfer destination substrate without being damaged, without adversely affecting the chip component C adjacent to the transfer target.

Therefore, when the transfer board of the present invention is used in an application in which a large number of chip parts are mounted on a wiring board at intervals, the chip breakage rate in the process can be suppressed to an extremely low level, which is required for repair. The cost can also be significantly reduced. Therefore, the present invention is suitable as a method for manufacturing an image display device in which a TFT substrate is used as a final wiring board and an LED chip is used as a chip component, and a high-quality image display device using one million or more LEDs. It is extremely suitable as a manufacturing method for LEDs.

1 1st transfer substrate 2 2nd transfer substrate 3 Transfer destination substrate Stage 4 Transfer substrate holding means 5 Mask arrangement means 6 Light source 7 Laser light source 8 Slide mechanism 10 Base substrate 11 Adhesive layer 11A Adhesive part 11B Low adhesive part (non-adhesive part)
20 Base board 21 Adhesive layer 22 Shock absorption layer 70 Laser light source slider 101 Transfer device 102 Spacer B Bump C, CW Chip parts L Laser light PM Photomask S Wiring board UV Light W wafer board containing wavelength to cure adhesive layer

Claims (8)

A transfer method in which a chip component held on a transfer substrate is transferred to a transfer destination substrate via a photocurable adhesive layer.
An exposure step in which the adhesive layer is pattern-exposed with light having a wavelength that cures the adhesive layer to partially reduce the adhesive force of the adhesive layer.
A transfer method including a laser lift-off step of transferring the chip component to the transfer destination substrate by a laser lift-off method after the exposure step. The transfer method according to claim 1.
A transfer method in which a light-shielding region that is shielded from light during the exposure step is provided at least within a laser irradiation range for irradiating a laser in the laser lift-off step. The transfer method according to claim 2, wherein the light-shielding region provided in the laser irradiation range corresponds to a range of 5 μm square or more and 50 μm square or less. The transfer method according to claim 1.
A transfer method in which the laser beam used in the laser lift-off step is a Gaussian beam and the laser irradiation range is larger than the size of the chip component. An LED chip is used as the chip component.
The LED chip transferred to the transfer destination substrate by the transfer method according to any one of claims 1 to 4.
A method for manufacturing an image display device including a step of transferring from a transfer destination substrate to a TFT substrate. An LED chip is used as the chip component, and a TFT substrate is used as the transfer destination substrate.
A method for manufacturing an image display device, comprising a step of transferring the LED chip to the TFT substrate by the transfer method according to any one of claims 1 to 4. A transfer device that transfers chip components held on a transfer substrate to a transfer destination substrate via a photocurable adhesive layer.
A transfer substrate holding means for holding the transfer substrate and
A light source that irradiates the adhesive layer with light having a wavelength that cures the adhesive layer from the opposite side of the chip holding surface of the transfer substrate.
A mask arrangement having a function of arranging a mask that partially blocks the light between the transfer board and the light source to align the chip components and a function of retracting the mask from the transfer board. Means and
A transfer device including a laser light source that irradiates a chip component with a laser beam from the opposite side of the chip holding surface of the transfer substrate with the mask retracted from the transfer substrate. A transfer device that transfers chip components held on a transfer substrate to a transfer destination substrate via a photocurable adhesive layer.
A transfer substrate holding means for holding the transfer substrate and
A function of lowering the adhesive force of the adhesive layer by irradiation while scanning the laser beam having a wavelength of curing the adhesive layer from the opposite side of the chip holding surface before Symbol transfer substrate partially laser the chip component A transfer device including a laser light source having a function of irradiating a laser beam transferred from the transfer substrate to the transfer destination substrate by a lift-off method.

Images