Transfer method, transfer unit, manufacturing method of display device, and manufacturing method of mounting substrate

Abstract

The present application is a transfer method for transferring a structure to a transfer destination, the transfer method including: preparing a release sheet including a substrate, a resin layer provided on the substrate and having a transmittance of a transfer laser of 90% or more, and a structure held on a surface of the resin layer opposite to the substrate; irradiating the transfer laser from a surface of the substrate opposite to the resin layer to the substrate; and the irradiated transfer laser being transmitted through the substrate and the resin layer, thermally decomposing at least a part of the resin layer at an interface between the structure and the resin layer, and transferring the structure from the release sheet to the transfer destination. Thus, a transfer method capable of transferring a structure to a transfer destination with high precision can be provided.

Description

Technical Field

[0001] This invention relates to a transfer method, a transfer unit, a method for manufacturing a display device, and a method for manufacturing a mounting substrate. Background Technology

[0002] In recent years, with the miniaturization of semiconductor components, the transfer (displacement) technology of microstructures using adhesive resin has attracted much attention as an assembly method for electrical / electronic application products that use semiconductor components. In particular, the development of technology to manufacture LED displays for applications such as signage, television, medical, automotive, and smartphones by transferring (displacement) tens of thousands of miniature light-emitting diodes (LEDs) (LEDs with a short side of 100 μm or more to several tens of micrometers) or micro-LEDs (LEDs with a short side of less than 100 μm, and even less than 50 μm) at one time has become active.

[0003] To date, methods for transferring microstructures such as microLEDs using silicone adhesive hardeners, as well as methods for mounting them on circuit boards, have been developed as donor substrates or transfer printing impression materials (e.g., Patent Document 1).

[0004] In addition, a technology for transferring semiconductor chips with high precision by relaxing the impact during the transfer process has also been proposed (e.g., Patent Document 2).

[0005] Existing technical documents

[0006] Patent documents

[0007] Patent Document 1: Japanese Patent Application Publication No. 2021-34610

[0008] Patent Document 2: Japanese Patent Application Publication No. 2019-67892

[0009] Non-patent literature

[0010] Non-patent literature 1: Kristin M. Charipar et al., “Use of an Elastomeric Donor for LIFT of Metal Foils”, Journal of Laser Micro / Nanoengineering, Vol. 13, No. 2, 2018. Summary of the Invention

[0011] The problem that the invention aims to solve

[0012] Furthermore, as a laser-based structural transfer technique, there are techniques that use laser-induced phenomena such as laser ablation to transfer the object to be transferred. In this technique, the method of moving the object to be transferred along the direction of laser irradiation is called Laser-Induced Forward Transfer (LIFT) (e.g., Non-Patent Document 1). Conversely, the method of returning the object to be transferred along the direction of laser irradiation is called Laser-Induced Back Transfer (LIBT).

[0013] In existing LIFT systems, a release plate is used, comprising a substrate and a holding layer formed on the substrate to hold the structure. The release plate is then peeled (transferred) from the interface between the substrate and the holding layer by laser ablation. This method allows for the transfer of the structure to its destination with a certain degree of precision.

[0014] However, in existing LIFT systems, the subtle variations in the energy density distribution of each laser pulse and the deviation in energy density of each laser emission cause changes in the amount of gas generated in each transfer and laser-irradiated surface, which also affects the flying direction and speed of the structure. Due to these effects, improvements in transfer position accuracy are limited.

[0015] The present invention is made to solve the aforementioned problems, and its purpose is to provide a transfer method, a transfer unit, a method for manufacturing a display device, and a method for manufacturing a mounting substrate. The transfer method can transfer a structure to a transfer destination with high precision, the transfer unit can transfer a structure to a transfer destination with high precision, the method for manufacturing a display device can manufacture a display device in which a structure is configured with high precision on a wiring substrate, and the method for manufacturing a mounting substrate can manufacture a mounting substrate in which a structure is configured with high precision on a wiring substrate.

[0016] Methods for solving problems

[0017] To address the aforementioned problem, this invention provides a transfer method for transferring a structure to a transfer destination, the transfer method comprising:

[0018] Prepare a release plate, the release plate comprising a substrate, a resin layer disposed on the substrate and having a transmittance of the transfer laser of 90% or more, and a structure held on the resin layer on the side opposite to the substrate;

[0019] The transfer laser is incident on the substrate from a side opposite to the resin layer; and

[0020] The incident transfer laser passes through the substrate and the resin layer, causing at least a portion of the resin layer to thermally decompose at the interface where the structure and the resin layer are in contact, thereby transferring the structure from the release plate to the transfer destination.

[0021] If the transfer method of this invention is used, the variation in the amount of gas generated in the laser-irradiated surface during each transfer can be suppressed, making the flying direction and speed of the structure uniform. Therefore, according to the transfer method of this invention, the structure can be transferred to the transfer destination with high precision.

[0022] For example, the thermal decomposition of the resin layer at the interface is generated by using the transfer laser that passes through the substrate and the resin layer to heat the surface of the structure in contact with the resin layer to above the thermal decomposition temperature of the resin layer.

[0023] In the transfer method of the present invention, for example, a transfer laser that passes through the substrate and the resin layer can be used to heat the surface of the structure in contact with the resin layer to above the thermal decomposition temperature of the resin layer, thereby causing thermal decomposition of the resin layer and peeling the structure off from the release plate.

[0024] The thermal decomposition temperature of the material constituting the surface of the structure in contact with the resin layer is preferably higher than the thermal decomposition temperature of the resin layer.

[0025] If the thermal decomposition temperature of the material constituting the surface of the structure that is in contact with the resin layer is higher than that of the resin layer, then the transfer can be performed while preventing the deterioration of the structure.

[0026] The thermal decomposition temperature of the material constituting the surface of the structure in contact with the resin layer is preferably 200°C or higher than that of the resin layer.

[0027] In this case, structural deterioration can be prevented more reliably.

[0028] For example, the resin layer may contain dimethylpolysiloxane.

[0029] In this invention, the constituent materials of the resin layer are not particularly limited, and the resin layer may, for example, contain dimethylpolysiloxane.

[0030] For example, the surface of the structure in contact with the resin layer may contain gallium nitride.

[0031] In this invention, the constituent materials of the structure are not particularly limited. For example, the surface of the structure that is in contact with the resin layer may contain gallium nitride (GaN).

[0032] For example, the resin layer may contain dimethylpolysiloxane, and the surface of the structure in contact with the resin layer may contain gallium nitride.

[0033] For example, the resin layer may contain dimethylpolysiloxane, and the surface of the structure in contact with the resin layer may contain gallium nitride.

[0034] Alternatively, the resin layer may comprise polyimide, and the surface of the structure in contact with the resin layer may comprise gallium phosphide.

[0035] Alternatively, the resin layer may contain polyimide, and the surface of the structure in contact with the resin layer may contain gallium phosphide (GaP).

[0036] For example, the transfer laser may be an excimer laser with a wavelength of 248 nm.

[0037] As a transfer laser, an excimer laser with a wavelength of 248 nm can be used, for example.

[0038] Furthermore, this invention provides a transfer unit for transferring a structure to a transfer destination, the transfer unit comprising:

[0039] The light source vibrates to produce a transfer laser;

[0040] The release plate includes a substrate, a resin layer disposed on the substrate and having a transmittance of the transfer laser of 90% or more, and a structure held on the resin layer on the side opposite to the substrate.

[0041] The holding mechanism is designed to hold the transfer destination;

[0042] The alignment mechanism is configured to clamp the release plate in the middle so that the light source and the holding mechanism face each other; and

[0043] The controller is configured to control the oscillation of the transfer laser emitted by the light source, such that the transfer laser is incident on the substrate from a surface opposite to the resin layer, and thermally decomposes at least a portion of the resin layer at the interface where the structure and the resin layer are in contact.

[0044] If the transfer unit of this invention is used, the variation in the amount of gas generated in the laser-irradiated surface during each transfer can be suppressed, making the flying direction and speed of the structure uniform. Therefore, according to the transfer unit of this invention, the structure can be transferred to the transfer destination with high precision.

[0045] The transfer unit may, for example, thermally decompose at least a portion of the resin layer at the interface where the structure and the resin layer are in contact, and transfer the structure from the release plate to the transfer destination.

[0046] In the transfer unit of the present invention, for example, at least a portion of the resin layer may be thermally decomposed at the interface where the structure is in contact with the resin layer, and the structure may be transferred from the release plate to the transfer destination.

[0047] In the transfer unit, for example, the thermal decomposition of the resin layer at the interface can be generated by using the transfer laser that transmits through the substrate and the resin layer to heat the surface of the structure in contact with the resin layer to above the thermal decomposition temperature of the resin layer.

[0048] In the transfer unit of the present invention, for example, a transfer laser that passes through the substrate and the resin layer can be used to heat the surface of the structure that is in contact with the resin layer to above the thermal decomposition temperature of the resin layer. As a result, thermal decomposition of the resin layer at the interface can be generated, and the structure can be peeled off from the release plate.

[0049] The thermal decomposition temperature of the material constituting the surface of the structure in contact with the resin layer is preferably higher than the thermal decomposition temperature of the resin layer.

[0050] If the thermal decomposition temperature of the material constituting the surface of the structure that is in contact with the resin layer is higher than that of the resin layer, then the transfer can be performed while preventing the deterioration of the structure.

[0051] The thermal decomposition temperature of the material constituting the surface of the structure in contact with the resin layer is preferably 200°C or higher than that of the resin layer.

[0052] This type of transfer unit can more reliably prevent structural degradation.

[0053] For example, the resin layer may contain dimethylpolysiloxane.

[0054] In this invention, the constituent materials of the resin layer are not particularly limited, and the resin layer may, for example, contain dimethylpolysiloxane.

[0055] For example, the surface of the structure in contact with the resin layer may contain gallium nitride.

[0056] In this invention, the constituent materials of the structure are not particularly limited. For example, the surface of the structure that is in contact with the resin layer may contain gallium nitride (GaN).

[0057] For example, the resin layer may contain dimethylpolysiloxane, and the surface of the structure in contact with the resin layer may contain gallium nitride.

[0058] For example, the resin layer may contain dimethylpolysiloxane, and the surface of the structure in contact with the resin layer may contain gallium nitride.

[0059] Alternatively, the resin layer may comprise polyimide, and the surface of the structure in contact with the resin layer may comprise gallium phosphide.

[0060] Alternatively, the resin layer may contain polyimide, and the surface of the structure in contact with the resin layer may contain gallium phosphide (GaP).

[0061] For example, the transfer laser may be an excimer laser with a wavelength of 248 nm.

[0062] As a transfer laser, an excimer laser with a wavelength of 248 nm can be used, for example.

[0063] Furthermore, this invention provides a method for manufacturing a display device, which involves transferring a structure onto a wiring substrate. The method for manufacturing the display device includes:

[0064] Prepare the wiring board;

[0065] Prepare a release plate, the release plate comprising a substrate, a resin layer disposed on the substrate and having a transmittance of the transfer laser of 90% or more, and a structure held on the resin layer on the side opposite to the substrate;

[0066] The transfer laser is incident on the substrate from a side opposite to the resin layer; and

[0067] The incident transfer laser passes through the substrate and the resin layer, causing at least a portion of the resin layer to thermally decompose at the interface where the structure and the resin layer are in contact, thereby transferring the structure from the release plate to the wiring substrate.

[0068] According to the manufacturing method of the display device of the present invention, the variation in the amount of gas generated in the transfer and laser irradiation surfaces can be suppressed, and the flying direction and speed of the structure can be made uniform. Therefore, a display device in which the structure is arranged on the wiring board with high precision can be manufactured.

[0069] In addition, this invention provides a method for manufacturing a mounting substrate, which involves transferring a structure onto a wiring substrate. The method for manufacturing the mounting substrate includes:

[0070] Prepare the wiring board;

[0071] Prepare a release plate, the release plate comprising a substrate, a resin layer disposed on the substrate and having a transmittance of the transfer laser of 90% or more, and a structure held on the resin layer on the side opposite to the substrate;

[0072] The transfer laser is incident on the substrate from a side opposite to the resin layer; and

[0073] The incident transfer laser passes through the substrate and the resin layer, causing at least a portion of the resin layer to thermally decompose at the interface where the structure and the resin layer are in contact, thereby transferring the structure from the release plate to the wiring substrate.

[0074] According to the manufacturing method of the mounting substrate of the present invention, the variation in the amount of gas generated in the transfer and laser irradiation surfaces can be suppressed, and the flying direction and speed of the structure can be made uniform. Therefore, a mounting substrate on which the structure is configured with high precision on the wiring board can be manufactured.

[0075] The effects of the invention

[0076] As described above, if the transfer method of the present invention is used, the structure can be transferred to the transfer destination with high precision.

[0077] In addition, if it is the transfer unit of the present invention, the structure can be transferred to the transfer destination with high precision.

[0078] Furthermore, if the method for manufacturing the display device of the present invention is adopted, a display device in which the structure is configured on the wiring substrate with high precision can be manufactured.

[0079] Furthermore, if the method for manufacturing the mounting substrate of the present invention is adopted, a mounting substrate with a structure can be manufactured to be configured on the wiring board with high precision. Attached Figure Description

[0080] [ Figure 1 [Illustration] is a schematic diagram illustrating an example of the transfer unit of the present invention.

[0081] [ Figure 2 ]yes Figure 1 A schematic enlarged cross-sectional view of a portion of the release plate shown.

[0082] [ Figure 3 [Illustration] is a schematic enlarged cross-sectional view showing a portion of an example of the transfer method of the present invention.

[0083] [ Figure 4 [Illustration] is a schematic cross-sectional view showing a portion of another example of the transfer method of the present invention. Detailed Implementation

[0084] As mentioned above, there is a need to develop a transfer method that can transfer structures to the transfer destination with high precision.

[0085] The inventors have conducted repeated and diligent research on the aforementioned problem and have discovered that by using a release plate comprising a substrate, a resin layer disposed on the substrate with a transfer laser transmittance of 90% or more, and a structure held on the side of the resin layer opposite to the substrate, the transfer laser is incident on the substrate from the side opposite to the resin layer. Using the incident transfer laser, at least a portion of the resin layer is thermally decomposed at the interface between the structure and the resin layer, transferring the structure from the release plate to the transfer destination. This allows for high-precision transfer of the structure to the transfer destination, thus completing the present invention.

[0086] That is, the present invention is a transfer method for transferring a structure to a transfer destination, the transfer method comprising:

[0087] Prepare a release plate, the release plate comprising a substrate, a resin layer disposed on the substrate and having a transmittance of the transfer laser of 90% or more, and a structure held on the resin layer on the side opposite to the substrate;

[0088] The transfer laser is incident on the substrate from a side opposite to the resin layer; and

[0089] The incident transfer laser passes through the substrate and the resin layer, causing at least a portion of the resin layer to thermally decompose at the interface where the structure and the resin layer are in contact, thereby transferring the structure from the release plate to the transfer destination.

[0090] In addition, the present invention is a transfer unit for transferring a structure to a transfer destination, the transfer unit comprising:

[0091] The light source vibrates to produce a transfer laser;

[0092] The release plate includes a substrate, a resin layer disposed on the substrate and having a transmittance of the transfer laser of 90% or more, and a structure held on the resin layer on the side opposite to the substrate.

[0093] The holding mechanism is designed to hold the transfer destination;

[0094] The alignment mechanism is configured to clamp the release plate in the middle so that the light source and the holding mechanism face each other; and

[0095] The controller is configured to control the oscillation of the transfer laser emitted by the light source, such that the transfer laser is incident on the substrate from a surface opposite to the resin layer, and thermally decomposes at least a portion of the resin layer at the interface where the structure and the resin layer are in contact.

[0096] In addition, the present invention provides a method for manufacturing a display device, wherein a structure is transferred onto a wiring substrate, the method comprising:

[0097] Prepare the wiring board;

[0098] Prepare a release plate, the release plate comprising a substrate, a resin layer disposed on the substrate and having a transmittance of the transfer laser of 90% or more, and a structure held on the resin layer on the side opposite to the substrate;

[0099] The transfer laser is incident on the substrate from a side opposite to the resin layer; and

[0100] The incident transfer laser passes through the substrate and the resin layer, causing at least a portion of the resin layer to thermally decompose at the interface where the structure and the resin layer are in contact, thereby transferring the structure from the release plate to the wiring substrate.

[0101] In addition, the present invention provides a method for manufacturing a mounting substrate, wherein a structure is transferred onto a wiring substrate, the method for manufacturing the mounting substrate comprising:

[0102] Prepare the wiring board;

[0103] Prepare a release plate, the release plate comprising a substrate, a resin layer disposed on the substrate and having a transmittance of the transfer laser of 90% or more, and a structure held on the resin layer on the side opposite to the substrate;

[0104] The transfer laser is incident on the substrate from a side opposite to the resin layer; and

[0105] The incident transfer laser passes through the substrate and the resin layer, causing at least a portion of the resin layer to thermally decompose at the interface where the structure and the resin layer are in contact, thereby transferring the structure from the release plate to the wiring substrate.

[0106] The present invention will now be described in detail, but the present invention is not limited thereto.

[0107] [Transfer Unit]

[0108] The transfer unit of the present invention transfers the structure to the transfer destination, the transfer unit comprising:

[0109] The light source vibrates to produce a transfer laser;

[0110] The release plate includes a substrate, a resin layer disposed on the substrate and having a transmittance of the transfer laser of 90% or more, and a structure held on the resin layer on the side opposite to the substrate.

[0111] The holding mechanism is designed to hold the transfer destination;

[0112] The alignment mechanism is configured to clamp the release plate in the middle so that the light source and the holding mechanism face each other; and

[0113] The controller is configured to control the oscillation of the transfer laser emitted by the light source, such that the transfer laser is incident on the substrate from a surface opposite to the resin layer, and thermally decomposes at least a portion of the resin layer at the interface where the structure and the resin layer are in contact.

[0114] The following is for reference Figures 1-3 An example of the transfer unit of the present invention will be described below. However, the transfer unit of the present invention is not limited to... Figures 1-3 The example shown.

[0115] Figure 1 The transfer unit 10 shown is a transfer unit that transfers the structure 20 to the transfer destination 30.

[0116] Figure 1 The transfer unit 10 shown includes a light source 2, a release plate 1, a holding mechanism 3, an alignment mechanism 4, and a controller 5.

[0117] Light source 2 is configured to oscillate and emit a transfer laser L. Figure 1 In this example, the light source 2 includes a laser oscillator 21 that oscillates the transfer laser L, and a reflector 22 that changes the orientation of the laser oscillator 21, but is not limited to these structures. For example, the light source 2 may also include a galvano scanner, which includes a reflector 22, a scanner that drives the reflector 22, and a controller that controls the reflector 22 and the scanner.

[0118] The laser oscillator 21 can be either pulsed to produce the transfer laser L or continuously oscillating to produce the transfer laser L. A laser oscillator 21 that pulses to produce the transfer laser L is preferred because it can irradiate only the appropriate area with the appropriate energy density of the transfer laser.

[0119] The light source 2 may include a shaping optical system that shapes the energy distribution of the transfer laser L and / or a photomask with adjusted irradiation shape between the laser oscillator 21 and the release plate 1.

[0120] As detailed below, the wavelength of the transfer laser L is not particularly limited as long as it is a wavelength capable of thermally decomposing at least a portion of the resin layer at the interface between the structure and the resin layer. For example, the transfer laser L can be an excimer laser (KrF excimer laser) with a wavelength of 248 nm. Other examples include ArF excimer lasers (wavelength 193 nm), XeCl excimer lasers (wavelength 308 nm), and XeF excimer lasers (wavelength 353 nm). From the viewpoint of practical application and ease of acquisition, a KrF excimer laser is preferred.

[0121] Figure 2 yes Figure 1 A schematic enlarged cross-sectional view of a portion of the release plate 1 included in the transfer unit 10 shown.

[0122] The release plate 1 includes a substrate 11, a resin layer 12 disposed on the substrate 11, and a structure 20 held on the surface of the resin layer 12 opposite to the substrate 11. Figure 1 In the example, the release plate 1 includes multiple structures 20.

[0123] The substrate 11 is not particularly limited, and can be, for example, made of quartz. Preferably, the substrate 11 has a transmittance of 90% or more for the transfer laser L. In the transfer unit 10 of the present invention, as long as it is configured to thermally decompose at least a portion 12A of the resin layer 12 at the interface 13 where the structure 20 and the resin layer 12 meet, the transmittance of the transfer laser L on the substrate 11 is not particularly limited. If the transmittance of the transfer laser L on the substrate 11 is 90% or more, the attenuation of the energy of the transfer laser L from the light source 2 in the substrate layer 11 can be suppressed, thus enabling energy-efficient transfer.

[0124] The thickness of the substrate 11 can be set to, for example, 0.1 mm or more and 1 mm or less, but there is no particular limitation.

[0125] The transmittance of the transfer laser L over the resin layer 12 is 90% or higher. Here, transmittance refers to the transmittance when the transfer laser L is incident perpendicularly onto the surface of the resin layer 12; in other words, it is the transmittance along the thickness direction of the resin layer 12. This means that the absorptivity of the transfer laser L over the resin layer 12 is less than 10%, thereby effectively suppressing the ablation of the resin layer 12. The transmittance of the transfer laser L over the resin layer 12 can, for example, depend on the wavelength of the transfer laser L, as well as the material and thickness of the resin layer 12. The upper limit of transmittance is 100%, but from the viewpoint of material availability, it can also be around 98% or lower.

[0126] The material of the resin layer 12 is not particularly limited. For example, the resin layer 12 may contain dimethyl polysiloxane, polyimide, benzocyclobutene resin or silicone resin.

[0127] The thickness of the resin layer 12 is not particularly limited; for example, it can be set to be greater than 0.005 mm and less than 1 mm.

[0128] While not wishing to be limited, for a resin layer 12 containing dimethylpolysiloxane and with a thickness of 100 μm or less, the transmittance of a transfer laser L with a wavelength of 248 nm is 90% or more. Furthermore, when using a transfer laser with a wavelength other than 248 nm, the material contained in the resin layer or the thickness of the resin layer can be selected such that the transmittance of the wavelength of the transfer laser is 90% or more.

[0129] Structure 20 is the object to be transferred to the transfer destination 30. Structure 20 is not particularly limited. For example, structure 20 can be a micro LED, mini LED, or other LED chip, or it can be a semiconductor chip.

[0130] The constituent material of the structure 20 is not particularly limited. For example, the surface 20A of the structure 20 that is in contact with the resin layer 12 may contain gallium nitride (GaN) or gallium phosphide (GaP).

[0131] exist Figure 1 In the transfer unit 10 shown, the release plate 1 is held by the retainer 41.

[0132] The holding mechanism 3 is configured to hold the transfer destination 30.

[0133] The transfer destination 30 is not particularly limited as long as it can receive the structure 20. If the structure 20 is an LED chip, the transfer destination 30 can be a wiring board for a display device. Alternatively, if the structure 20 is a semiconductor chip, the transfer destination 30 can be a wiring board for mounting a substrate.

[0134] The details of the retaining mechanism 3 can be appropriately modified according to the shape of the transfer destination 30, etc. Figure 1 In the example, the holding mechanism 3 is the stage that holds and holds the transfer destination 30.

[0135] The alignment mechanism 4 is configured to clamp the release plate 1 in the middle so that the light source 2 and the holding mechanism 3 face each other. There are no limitations; in... Figure 1 In the example of the transfer unit 10 shown, the alignment mechanism 4 includes: a holder 41 for holding the release plate 1, a mechanism for positioning each component of the light source 2 (not shown), and a mechanism for positioning the holding mechanism 3 (not shown).

[0136] The controller 5 is configured to control the oscillation of the transfer laser L emitted by the light source 2. More specifically, the controller 5 is configured to control the oscillation of the transfer laser L emitted by the light source 2, such that the transfer laser L is incident on the substrate 11 from the surface opposite to the resin layer 12, for example... Figure 3 As shown, at least a portion 12A of the resin layer 12 is thermally decomposed at the interface 13 where the structure 20 and the resin layer 12 are in contact.

[0137] Further details about the transfer unit 10 will be provided later.

[0138] If the transfer unit 10 of this invention is used, the transfer method of this invention, as described in the following detailed description, can be implemented. The detailed reasons are explained in the following transfer method: by using the transfer unit of this invention, even if there are subtle variations in the laser irradiation energy density distribution or deviations in the energy density of each laser emission, variations in the amount of gas generated in each transfer and laser irradiation surface can be suppressed, resulting in uniform ejection direction and velocity of the structure. Therefore, according to the transfer method of this invention, the structure can be transferred to the transfer destination with high precision.

[0139] [Transfer Method]

[0140] A transfer method for transferring a structure to a transfer destination, the transfer method comprising:

[0141] Prepare a release plate, the release plate comprising a substrate, a resin layer disposed on the substrate and having a transmittance of the transfer laser of 90% or more, and a structure held on the resin layer on the side opposite to the substrate;

[0142] The transfer laser is incident on the substrate from a side opposite to the resin layer; and

[0143] The incident transfer laser passes through the substrate and the resin layer, causing at least a portion of the resin layer to thermally decompose at the interface where the structure and the resin layer are in contact, thereby transferring the structure from the release plate to the transfer destination.

[0144] The following is an example of the transfer method of the present invention, using... Figures 1-3 The transfer method of the transfer unit 10 shown will be described. However, the transfer method of the present invention is not limited to the examples described below, and other methods may also be used. Figures 1-3 The transfer is performed by a unit or device other than the transfer unit 10 shown.

[0145] First, prepare the release plate 1 as described earlier.

[0146] Next, the transfer laser L is incident on the substrate 11 of the release plate 1 from the side opposite to the resin layer 12.

[0147] The transfer laser L can be oscillated by the light source 2. For example, the transfer laser L can also be incident on the substrate 11 after passing from the laser oscillator 21 through a forming optical system that shapes the energy distribution of the transfer laser L and / or a photomask with the irradiation shape adjusted.

[0148] Next, the incident transfer laser L passes through the substrate 11 and the resin layer 12. As previously explained, the transmittance of the transfer laser in the resin layer 12 is over 90%, and therefore the absorption rate of the transfer laser is less than 10%, which can suppress the temperature rise and ablation caused by the passage of laser light.

[0149] like Figure 3 As shown, the transfer laser L, which passes through the substrate 11 and the resin layer 12, causes at least a portion 12A of the resin layer 12 to thermally decompose at the interface 13 where the structure 20 and the resin layer 12 are connected.

[0150] While not wishing to be bound by theory, the transfer laser L, passing through the substrate 11 and resin layer 12, is incident on the surface 20A of the interface 13 constituting the structure 20. The surface 20A of the structure 20 is heated by the incident transfer laser L. The surface 20A of the structure 20 can be heated to above the thermal decomposition temperature of the resin layer 12. The heat thus generated is transferred to the resin layer 12. The resin layer 12 has a temperature gradient that decreases with distance from the interface 13. Furthermore, a portion 12A of the interface 13 constituting the resin layer 12 heats up to the temperature at which thermal decomposition occurs. Therefore, this portion 12A undergoes thermal decomposition. Thus, the area near the interface of the structure 20 in contact with the resin layer 12 is preferably made of a material with a high absorptivity for the transfer laser L.

[0151] Structure 20 can be peeled off from release plate 1 by thermal decomposition (ablation) of a portion 12A of resin layer 12. For example... Figure 3 As shown by the dashed line, the stripped structure 20 can reach the transfer destination 30. Thus, the structure 20 is transferred to the transfer destination 30.

[0152] In existing LIFT processes, laser irradiation is used to ablate portions of the resin layer 12 other than the portion 12A constituting the interface 30. The inventors have discovered that because the ablation location changes due to variations in the subtle energy density distribution of each laser pulse and deviations in the energy density of each laser emission, the amount of gas generated in each transfer and laser-irradiated surface deviates. Furthermore, this deviation in the amount of gas generated in each transfer and laser-irradiated surface also affects the ejection direction and speed of the structure 20, becoming a bottleneck for improving transfer accuracy.

[0153] According to the transfer method of the present invention, the portion 12A constituting the interface 30 in the resin layer 12 is thermally decomposed (ablated). Therefore, even if there are subtle variations in the distribution of laser irradiation energy density or deviations in the energy density of each laser emission, variations in the amount of gas generated in each transfer and laser irradiation surface can be suppressed, thereby making the flight direction and speed of the structure 20 uniform and improving the transfer accuracy.

[0154] That is, according to the transfer method of the present invention, the structure 20 can be transferred to the transfer destination 30 with high precision.

[0155] Furthermore, the transfer method of the present invention differs from the prior art. Instead of actively ablating the resin layer 12, it utilizes thermal decomposition at the interface 30, thus achieving high transmittance of the transfer laser. This allows the use of highly transparent materials that are difficult to utilize for LIFT ablation in existing technologies. In other words, LIFT can be effectively performed using a resin layer with a transfer laser transmittance of 90% or more, utilizing materials such as dimethylpolysiloxane.

[0156] In addition, unlike LIFT which only utilizes the difference in thermal expansion between structure 12 and resin layer 12, the transfer accuracy can be improved due to the accompanying thermal decomposition of resin layer 12.

[0157] Hereinafter, any aspects of the transfer method and transfer unit of the present invention will be described.

[0158] For example, in this invention, the thermal decomposition of the resin layer 12 at interface 13 can be generated by using a transfer laser L that passes through the substrate 11 and the resin layer 12 to heat the surface 20A of the structure 20 that is in contact with the resin layer 12 to above the thermal decomposition temperature of the resin layer 12.

[0159] If the thermal decomposition temperature of the constituent material of the surface 20A of the structure 20 that is in contact with the resin layer 12 is higher than the thermal decomposition temperature of the resin layer 12, then the transfer can be performed while preventing the deterioration of the structure 20.

[0160] In particular, if the thermal decomposition temperature of the constituent material of the surface 20A of the structure 20 in contact with the resin layer 12 is more than 200°C higher than the thermal decomposition temperature of the resin layer 12, the deterioration of the structure 20 can be prevented more reliably. There is no particular upper limit to the difference in thermal decomposition temperatures; for example, it can be set to around 500°C.

[0161] Furthermore, if the surface 20A of the structure 20 in contact with the resin layer 12 becomes a thin film that is easily removed through thermal decomposition, the surface 20A of the structure 20 in contact with the resin layer 12 can be heated to a temperature above the thermal decomposition temperature. For example, when gallium nitride is used as the material of the structure 20, significant thermal decomposition occurs through heating to above 900°C, generating a gallium metal film, which can then be removed using an acidic aqueous solution such as hydrochloric acid. Furthermore, depending on the solubility of the generated film, removal can be achieved not only with the acidic aqueous solution but also with an alkaline aqueous solution. This reduces the constraints on the materials used in the structure 20 and the resin layer 12, allowing for more diverse combinations.

[0162] For example, the resin layer 12 may contain dimethylpolysiloxane, and the surface 20A of the structure 20 in contact with the resin layer 12 may contain gallium nitride or gallium phosphide.

[0163] This combination of materials is suitable for use with a transfer laser L wavelength of 248 nm.

[0164] As other forms, for example, the resin layer 12 may contain polyimide or benzocyclobutene resin, and the surface 20A of the structure 20 in contact with the resin layer 12 may contain gallium nitride or gallium phosphide.

[0165] The output of the transfer laser L can be appropriately selected.

[0166] In addition, Figures 1-3 The example shown illustrates a gap-separated LIFT (Limited-Input Transfer). In conventional gap-separated LIFT, the deviation in the amount of gas generated within the laser-irradiated surface, as previously described, significantly degrades the positional accuracy of the transfer. In contrast, the transfer method and transfer unit of the present invention can suppress deviations in the amount of gas generated within the laser-irradiated surface; therefore, for example, even with a gap of 300 μm, the transfer of the structure 20 can be performed with high precision.

[0167] Alternatively, in the transfer method and transfer unit 1 of the present invention, for example, as shown in the example... Figure 4 As shown, the release plate 1 and the transfer destination 30 can also be configured such that the structure 20 is in contact with the transfer destination 30. LIFT performed in this state can be referred to as contact LIFT, for example. If the transfer method of the present invention is set as contact LIFT, the transfer of the structure 20 can be performed with higher precision.

[0168] Furthermore, the transfer method according to the present invention minimizes the ablation of the resin layer 12 compared to the prior art. In other words, the thermal decomposition of the resin layer 12 is concentrated near the interface with the structure 20. Therefore, residues or carbonaceous debris from the resin layer 12 are easily reduced in the transfer destination 30. Thus, the present invention can be used to suppress the generation of residues or carbonaceous debris from the resin layer 12 even when high-precision transfer is not required or when high precision is achieved by other means. In addition, when the structure 20 is an LED chip and the surface in contact with the resin layer 12 is the light-emitting surface, it is important to suppress the generation of such residues or carbonaceous debris.

[0169] Furthermore, if the thermal decomposition of the resin layer 12 can be concentrated near the interface with the structure 20, the transmittance of the transfer laser on the resin layer does not need to be above 90%, and can be less than 90%. In this case, in order to suppress ablation caused by the absorption of the transfer laser on the resin layer, it is expected that ablation can be suppressed by reducing the thickness of the resin layer or adjusting the irradiation dose of the transfer laser.

[0170] [Manufacturing method of display device and manufacturing method of mounting substrate]

[0171] The manufacturing method of the display device of the present invention involves transferring a structure onto a wiring substrate, the manufacturing method of the display device comprising:

[0172] Prepare the wiring board;

[0173] Prepare a release plate, the release plate comprising a substrate, a resin layer disposed on the substrate and having a transmittance of the transfer laser of 90% or more, and a structure held on the resin layer on the side opposite to the substrate;

[0174] The transfer laser is incident on the substrate from a side opposite to the resin layer; and

[0175] The incident transfer laser passes through the substrate and the resin layer, causing at least a portion of the resin layer to thermally decompose at the interface where the structure and the resin layer are in contact, thereby transferring the structure from the release plate to the wiring substrate.

[0176] In other words, the manufacturing method of the display device of the present invention can also be called the manufacturing method that includes setting the transfer destination as a wiring substrate and transferring the structure to the wiring substrate in the transfer method of the present invention.

[0177] According to the manufacturing method of the display device of the present invention, for the reasons explained above, the variation in the amount of gas generated in the transfer and laser irradiation surfaces can be suppressed, and the flying direction and speed of the structure can be made uniform. Therefore, a display device in which the structure is arranged on the wiring board with high precision can be manufactured.

[0178] Furthermore, the method for manufacturing the mounting substrate of the present invention transfers the structure onto the wiring substrate, the method for manufacturing the mounting substrate comprising:

[0179] Prepare the wiring board;

[0180] Prepare a release plate, the release plate comprising a substrate, a resin layer disposed on the substrate and having a transmittance of the transfer laser of 90% or more, and a structure held on the resin layer on the side opposite to the substrate;

[0181] The transfer laser is incident on the substrate from a side opposite to the resin layer; and

[0182] The incident transfer laser passes through the substrate and the resin layer, causing at least a portion of the resin layer to thermally decompose at the interface where the structure and the resin layer are in contact, thereby transferring the structure from the release plate to the wiring substrate.

[0183] In other words, the method for manufacturing the mounting substrate of the present invention can also be called the following manufacturing method, which includes a method in the transfer method of the present invention where the transfer destination is a wiring substrate and the structure is transferred to the wiring substrate.

[0184] According to the method for manufacturing the mounting substrate of the present invention, for the reasons explained above, the variation in the amount of gas generated in the transfer and laser irradiation surfaces can be suppressed, and the flying direction and speed of the structure can be made uniform. Therefore, a mounting substrate in which the structure is configured on the wiring board with high precision can be manufactured.

[0185] Example

[0186] The present invention will now be specifically described using examples and comparative examples, but the present invention is not limited thereto.

[0187] (Example)

[0188] In the embodiment, using Figures 1-3 The transfer unit 10 shown uses gap LIFT to transfer the structure 20.

[0189] As release plate 1, a release plate is prepared as follows, comprising: a quartz substrate 11, a resin layer 12 containing dimethylpolysiloxane, and 20 micro LED chips 20 held on the side of the substrate 11 opposite to the resin layer 12. The side 20A of the micro LED chips 20 in contact with the resin layer 12 contains gallium nitride.

[0190] As the light source 2, a laser oscillator 21 is prepared, which can oscillate to produce a pulsed excimer laser with a wavelength of 248 nm as the transfer laser L.

[0191] As the transfer destination 30, a donor plate with a silicone resin layer formed on the surface of a quartz substrate is prepared.

[0192] The transmittance of the transfer laser L in resin layer 12 is over 90%.

[0193] In the transfer unit prepared as described above, the alignment mechanism 4 and controller 5 are used to direct the transfer laser L onto the substrate 11 from the side opposite to the resin layer 12. The output of the transfer laser L is controlled so that it passes through the substrate 11 and the resin layer 12, causing thermal decomposition of a portion of the resin layer 12 at the interface 13 where the micro-LED chip 20 meets the resin layer 12. This transfers the micro-LED chip 20 from the release plate 1 to the transfer destination 30.

[0194] In this embodiment, the transfer to the target location can be performed with good accuracy. Furthermore, when observing the release plate 1 after the transfer in this embodiment, the resin layer 12 decomposes only near the surface where the micro-LED chip 20 is held.

[0195] Based on the results, it is believed that in the embodiment, since only the surface of the resin layer 12 containing the micro LED chip 20 can be decomposed during each transfer, the variation in the amount of gas generated in the surface during each transfer and laser irradiation can be suppressed, and the flying direction and speed of the micro LED chip 20 can be made uniform. Thus, the micro LED chip 20 can be transferred to the transfer destination 30 with high precision.

[0196] (Comparative example)

[0197] The output of the transfer laser L is controlled so that the transfer laser L passes through the substrate 11 and the resin layer 12, and prevents a portion of the resin layer 12 from thermally decomposing at the interface 13 where the micro LED chip 20 is connected to the resin layer 12. Otherwise, the transfer is performed in the same manner as in the embodiment.

[0198] In this comparative example, compared to the embodiment, several micro-LED chips 20 were not transferred to the desired positions. Furthermore, upon observing the release plate after transfer in the comparative example, thermal decomposition near the surface of the resin layer 12 where the micro-LED chips 20 were held could not be confirmed. Regarding the reason for the poorer transfer accuracy compared to the embodiment in the comparative example, it is believed that since the peeling was achieved solely by utilizing the difference in thermal expansion between the structure and the resin layer, positional misalignment in the surface direction is more likely to occur.

[0199] This instruction manual includes the following forms.

[0200] [1] A transfer method for transferring a structure to a transfer destination, the transfer method comprising:

[0201] Prepare a release plate, the release plate comprising a substrate, a resin layer disposed on the substrate and having a transmittance of the transfer laser of 90% or more, and a structure held on the resin layer on the side opposite to the substrate;

[0202] The transfer laser is incident on the substrate from a side opposite to the resin layer; and

[0203] The incident transfer laser passes through the substrate and the resin layer, causing at least a portion of the resin layer to thermally decompose at the interface where the structure and the resin layer are in contact, thereby transferring the structure from the release plate to the transfer destination.

[0204] [2] According to the transfer method described in [1], the thermal decomposition of the resin layer at the interface is generated by using the transfer laser that passes through the substrate and the resin layer to heat the surface of the structure in contact with the resin layer to above the thermal decomposition temperature of the resin layer.

[0205] [3] According to the transfer method described in [1] or [2], wherein the thermal decomposition temperature of the constituent material of the surface of the structure in contact with the resin layer is higher than the thermal decomposition temperature of the resin layer.

[0206] [4] According to the transfer method described in [3], the thermal decomposition temperature of the constituent material of the surface of the structure in contact with the resin layer is more than 200°C higher than the thermal decomposition temperature of the resin layer.

[0207] [5] The transfer method according to any one of [1] to [4], wherein the resin layer comprises dimethylpolysiloxane.

[0208] [6] The transfer method according to any one of [1] to [5], wherein the surface of the structure in contact with the resin layer comprises gallium nitride.

[0209] [7] The transfer method according to any one of [1] to [6], wherein the resin layer comprises dimethylpolysiloxane and the surface of the structure in contact with the resin layer comprises gallium nitride.

[0210] [8] The transfer method according to any one of [1] to [6], wherein the resin layer comprises polyimide and the surface of the structure in contact with the resin layer comprises gallium phosphide.

[0211] [9] The transfer method according to any one of [1] to [8], wherein the transfer laser is an excimer laser having a wavelength of 248 nm.

[0212]

[10] A transfer unit for transferring a structure to a transfer destination, the transfer unit comprising:

[0213] The light source vibrates to produce a transfer laser;

[0214] The release plate includes a substrate, a resin layer disposed on the substrate and having a transmittance of the transfer laser of 90% or more, and a structure held on the resin layer on the side opposite to the substrate.

[0215] The holding mechanism is designed to hold the transfer destination;

[0216] The alignment mechanism is configured to clamp the release plate in the middle so that the light source and the holding mechanism face each other; and

[0217] The controller is configured to control the oscillation of the transfer laser emitted by the light source, such that the transfer laser is incident on the substrate from a surface opposite to the resin layer, and thermally decomposes at least a portion of the resin layer at the interface where the structure and the resin layer are in contact.

[0218]

[11] According to the transfer unit of

[10] , at least a portion of the resin layer is thermally decomposed at the interface where the structure is in contact with the resin layer, and the structure is transferred from the release plate to the transfer destination.

[0219]

[12] According to the transfer unit described in

[11] , the thermal decomposition of the resin layer at the interface is generated by using the transfer laser that transmits through the substrate and the resin layer to heat the surface of the structure in contact with the resin layer to above the thermal decomposition temperature of the resin layer.

[0220]

[13] According to the transfer unit of

[10] or

[11] , wherein the thermal decomposition temperature of the constituent material of the surface of the structure in contact with the resin layer is higher than the thermal decomposition temperature of the resin layer.

[0221]

[14] According to the transfer unit of

[13] , the thermal decomposition temperature of the constituent material of the surface of the structure in contact with the resin layer is more than 200°C higher than the thermal decomposition temperature of the resin layer.

[0222]

[15] The transfer unit according to any one of

[10] to

[14] , wherein the resin layer comprises dimethylpolysiloxane.

[0223]

[16] The transfer unit according to any one of

[10] to

[15] , wherein the surface of the structure in contact with the resin layer comprises gallium nitride.

[0224]

[17] The transfer unit according to any one of

[10] to

[16] , wherein the resin layer comprises dimethylpolysiloxane and the surface of the structure in contact with the resin layer comprises gallium nitride.

[0225]

[18] The transfer unit according to any one of

[10] to

[16] , wherein the resin layer comprises polyimide and the surface of the structure in contact with the resin layer comprises gallium phosphide.

[0226]

[19] The transfer unit according to any one of

[10] to

[18] , wherein the light source oscillates an excimer laser having a wavelength of 248 nm.

[0227]

[20] A method for manufacturing a display device, comprising transferring a structure onto a wiring substrate, the method comprising:

[0228] Prepare the wiring board;

[0229] Prepare a release plate, the release plate comprising a substrate, a resin layer disposed on the substrate and having a transmittance of the transfer laser of 90% or more, and a structure held on the resin layer on the side opposite to the substrate;

[0230] The transfer laser is incident on the substrate from a side opposite to the resin layer; and

[0231] The incident transfer laser passes through the substrate and the resin layer, causing at least a portion of the resin layer to thermally decompose at the interface where the structure and the resin layer are in contact, thereby transferring the structure from the release plate to the wiring substrate.

[0232]

[21] A method for manufacturing a mounting substrate, comprising transferring a structure onto a wiring substrate, the method comprising:

[0233] Prepare the wiring board;

[0234] Prepare a release plate, the release plate comprising a substrate, a resin layer disposed on the substrate and having a transmittance of the transfer laser of 90% or more, and a structure held on the resin layer on the side opposite to the substrate;

[0235] The transfer laser is incident on the substrate from a side opposite to the resin layer; and

[0236] The incident transfer laser passes through the substrate and the resin layer, causing at least a portion of the resin layer to thermally decompose at the interface where the structure and the resin layer are in contact, thereby transferring the structure from the release plate to the wiring substrate.

[0237] Furthermore, this invention is not limited to the described embodiments. The described embodiments are examples, and any embodiment having a structure that is substantially the same as the technical concept described in the claims of this invention and achieving the same effect is included within the technical scope of this invention.

Claims

1. A transfer method for transferring a structure to a transfer destination, the transfer method comprising: Prepare a release plate, the release plate comprising a substrate, a resin layer disposed on the substrate and having a transmittance of the transfer laser of 90% or more, and a structure held on the resin layer on the side opposite to the substrate; The transfer laser is incident on the substrate from the side opposite to the resin layer; as well as The incident transfer laser passes through the substrate and the resin layer, causing at least a portion of the resin layer to thermally decompose at the interface where the structure and the resin layer are in contact, thereby transferring the structure from the release plate to the transfer destination.

2. The transfer method according to claim 1, wherein, The thermal decomposition of the resin layer at the interface is caused by using a transfer laser that transmits through the substrate and the resin layer to heat the surface of the structure in contact with the resin layer to above the thermal decomposition temperature of the resin layer.

3. The transfer method according to claim 1 or 2, wherein, The thermal decomposition temperature of the material constituting the surface of the structure in contact with the resin layer is higher than that of the resin layer.

4. The transfer method according to claim 3, wherein, The thermal decomposition temperature of the material constituting the surface of the structure in contact with the resin layer is more than 200°C higher than that of the resin layer.

5. The transfer method according to claim 1 or 2, wherein, The resin layer contains dimethylpolysiloxane.

6. The transfer method according to claim 1 or 2, wherein, The surface of the structure in contact with the resin layer contains gallium nitride.

7. The transfer method according to claim 3, wherein, The resin layer comprises dimethylpolysiloxane, and the surface of the structure in contact with the resin layer comprises gallium nitride.

8. The transfer method according to claim 3, wherein, The resin layer comprises polyimide, and the surface of the structure in contact with the resin layer comprises gallium phosphide.

9. The transfer method according to claim 1 or 2, wherein, The transfer laser is an excimer laser with a wavelength of 248 nm.

10. A transfer unit for transferring a structure to a transfer destination, the transfer unit comprising: The light source vibrates to produce a transfer laser; The release plate includes a substrate, a resin layer disposed on the substrate and having a transmittance of the transfer laser of 90% or more, and a structure held on the resin layer on the side opposite to the substrate. The holding mechanism is designed to hold the transfer destination; The alignment mechanism is configured to clamp the release plate in the middle so that the light source and the holding mechanism face each other; and The controller is configured to control the oscillation of the transfer laser emitted by the light source, such that the transfer laser is incident on the substrate from a surface opposite to the resin layer, and thermally decomposes at least a portion of the resin layer at the interface where the structure and the resin layer are in contact.

11. The transfer unit according to claim 10, wherein, At least a portion of the resin layer is thermally decomposed at the interface where the structure and the resin layer are in contact, and the structure is transferred from the release plate to the transfer destination.

12. The transfer unit according to claim 11, wherein, The thermal decomposition of the resin layer at the interface is caused by using the transfer laser that passes through the substrate and the resin layer to heat the surface of the structure in contact with the resin layer to above the thermal decomposition temperature of the resin layer.

13. The transfer unit according to claim 10 or 11, wherein, The thermal decomposition temperature of the material constituting the surface of the structure in contact with the resin layer is higher than that of the resin layer.

14. The transfer unit according to claim 13, wherein, The thermal decomposition temperature of the material constituting the surface of the structure in contact with the resin layer is more than 200°C higher than that of the resin layer.

15. The transfer unit according to claim 10 or 11, wherein, The resin layer contains dimethylpolysiloxane.

16. The transfer unit according to claim 10 or 11, wherein, The surface of the structure in contact with the resin layer contains gallium nitride.

17. The transfer unit according to claim 13, wherein, The resin layer comprises dimethylpolysiloxane, and the surface of the structure in contact with the resin layer comprises gallium nitride.

18. The transfer unit according to claim 13, wherein, The resin layer comprises polyimide, and the surface of the structure in contact with the resin layer comprises gallium phosphide.

19. The transfer unit according to claim 10 or 11, wherein, The light source oscillates to produce an excimer laser with a wavelength of 248 nm.

20. A method for manufacturing a display device, comprising transferring a structure onto a wiring substrate, the method comprising: Prepare the wiring board; Prepare a release plate, the release plate comprising a substrate, a resin layer disposed on the substrate and having a transmittance of the transfer laser of 90% or more, and a structure held on the resin layer on the side opposite to the substrate; The transfer laser is incident on the substrate from the side opposite to the resin layer; as well as The incident transfer laser passes through the substrate and the resin layer, causing at least a portion of the resin layer to thermally decompose at the interface where the structure and the resin layer are in contact, thereby transferring the structure from the release plate to the wiring substrate.

21. A method for manufacturing a mounting substrate, comprising transferring a structure onto a wiring substrate, the method comprising: Prepare the wiring board; Prepare a release plate, the release plate comprising a substrate, a resin layer disposed on the substrate and having a transmittance of the transfer laser of 90% or more, and a structure held on the resin layer on the side opposite to the substrate; The transfer laser is incident on the substrate from the side opposite to the resin layer; as well as The incident transfer laser passes through the substrate and the resin layer, causing at least a portion of the resin layer to thermally decompose at the interface where the structure and the resin layer are in contact, thereby transferring the structure from the release plate to the wiring substrate.

Images