Receiving substrate, method for manufacturing receiving substrate, laser-induced forward transfer method, holding method, and method for cleaning microstructure

Abstract

The present invention is a reception substrate for transferring and receiving a microstructure formed on a supply substrate by laser lift-off, the reception substrate having a curable resin layer on a surface on which the microstructure is transferred. As a result, it is possible to provide a receiving substrate capable of receiving the microstructure while suppressing damage, and capable of holding the microstructure while suppressing positional displacement and inclination.

Description

Technical Field

[0001] The present invention relates to a receiving substrate used for transferring microstructures such as mini light emitting diodes (hereinafter also referred to as mini LEDs) and micro light emitting diodes (hereinafter also referred to as micro LEDs), and a method for manufacturing the receiving substrate, a laser-induced forward transfer (LIFT) method for transferring the microstructures, a method for holding the microstructures on the receiving substrate, and a method for cleaning the microstructures. Background Art

[0002] In recent years, as semiconductor elements have become smaller, microstructure transfer technology using adhesive resins has attracted attention as a means of assembling electrical / electronic application products using semiconductor elements. In particular, the development of technology to manufacture LED displays for signage, televisions, medical, automotive, and smartphones by transferring tens of thousands of mini light emitting diodes (LEDs) (LED elements with short sides of 100 μm to hundreds of μm) or micro LEDs (LED elements with short sides of 100 μm or less, and even less than 50 μm) at a time has become active.

[0003] Conventionally, a method of transferring a microstructure such as a micro LED using a silicone adhesive hardened material as a donor substrate or a transfer stamp material, and a method of mounting the microstructure on a circuit board have been developed (Patent Document 1).

[0004] On the other hand, as a method for electrically connecting a transferred microstructure such as an LED element to a circuit substrate, the following method is known: solder particles (hereinafter also referred to as bumps) are applied to the electrodes of the microstructure and the microstructure is mounted on the wiring of the circuit substrate, and then the solder component contained in the bump is melted and connected by reflow. In the case of transferring such a microstructure including a bump, since the shape of the bump is mostly curved, the mounting posture on the donor plate is not the same, and there is a problem of tilting relative to the plane of the plate. In addition, for example, after laser lift-off (hereinafter also referred to as LLO (laser lift-off)) of a blue LED element, Ga will adhere to the surface of the microstructure, but if an aqueous hydrochloric acid solution is used as a cleaning liquid to remove it, the solder component will dissolve at the same time and the composition will change, and the melting point will rise during reflow, which will affect the next process. In addition, due to the impact during cleaning, the microstructure often falls off.

[0005] Prior art literature

[0006] Patent Literature

[0007] Patent Document 1: Japanese Patent Application Publication No. 2021-34610 Summary of the invention

[0008] Problems to be solved by the invention

[0009] The present invention is made to solve the above-mentioned problems, and its purpose is to provide a receiving substrate that can receive a microstructure while suppressing breakage and can hold the microstructure while suppressing positional displacement and tilt, a method for manufacturing such a receiving substrate, a laser induced forward transfer method that transfers the microstructure from a supply substrate to a receiving substrate while suppressing breakage and can hold the microstructure while suppressing positional displacement and tilt, a holding method that can suppress positional displacement and tilt of the microstructure, and a cleaning method that can clean the microstructure while suppressing detachment, positional displacement and tilt.

[0010] Technical means of solving problems

[0011] In order to solve the above-mentioned problem, the present invention provides a receiving substrate for transferring and receiving a microstructure formed on a supply substrate by laser lift-off, wherein the receiving substrate

[0012] A curable resin layer is provided on the surface on which the microstructure is transferred.

[0013] In the receiving substrate of the present invention, local stress can be prevented from being applied to the microstructure during laser lift-off (LLO), and the microstructure can be firmly held. Therefore, the receiving substrate of the present invention can receive the microstructure while suppressing damage, and can also suppress positional displacement and tilt to hold the microstructure.

[0014] For example, the curable resin layer is photocurable or thermocurable.

[0015] The curable resin layer is not particularly limited as long as it is curable, and may be, for example, photocurable or thermocurable.

[0016] For example, the curable resin layer may be in a B-stage state.

[0017] The curable resin layer may be in a B-stage state, that is, a semi-cured state. Such a resin layer is subjected to a secondary curing treatment after receiving the microstructure, thereby being able to hold the microstructure without causing positional displacement or tilt.

[0018] The curable resin layer is preferably in a gel state.

[0019] If it is a gel-like resin layer, it is possible to more reliably prevent the microstructure from being damaged during laser lift-off.

[0020] For example, the curable resin layer may be a silicone gel layer.

[0021] The curable resin layer is not limited, and may be, for example, a silicone gel layer.

[0022] The curable resin layer preferably has adhesion to the microstructure.

[0023] If such a resin layer is used, positional deviation of the received microstructure can be further prevented.

[0024] It is preferable that the hardness of the curable resin layer increases as it is cured.

[0025] If the resin layer increases in hardness by curing, the positional displacement or tilt of the microstructure can be further suppressed after curing.

[0026] Alternatively, it is also preferred that the curable resin layer improves its adhesive force to the microstructure or improves its holding force to the microstructure by curing.

[0027] If such a resin layer is used, it is possible to more reliably suppress positional deviation or tilt of the microstructure after curing.

[0028] Alternatively, it is also preferable that the curable resin layer becomes rubber-like by curing.

[0029] If the resin layer becomes rubbery by curing, the positional displacement or tilt of the microstructure can be further suppressed after curing.

[0030] In this case, for example, the storage elastic modulus of the curable resin layer may be 10 Pa to 1000 Pa at 25° C., and may become 1 MPa to 30 GPa by curing.

[0031] The curable resin layer may be, for example, a resin layer whose storage elastic modulus increases as it is cured.

[0032] In addition, the present invention provides a method for manufacturing a receiving substrate, wherein the receiving substrate has a curable resin layer, and the method for manufacturing the receiving substrate comprises:

[0033] A step of forming a layer of a resin capable of undergoing at least two curing reactions on one surface of a substrate for preparing a receiving substrate; and

[0034] A process of partially hardening the resin by performing a first hardening reaction.

[0035] If this manufacturing method is used, a receiving substrate having a curable resin layer can be manufactured by performing a process of locally curing the resin using the first curing reaction. In the receiving substrate, local stress can be prevented from being applied to the microstructure during laser stripping, and the microstructure can be firmly held. Therefore, the manufactured receiving substrate can receive the microstructure by laser stripping while suppressing damage, and can hold the microstructure while suppressing positional displacement or tilt.

[0036] For example, the at least two hardening reactions may include a combination of a light hardening reaction and a heat hardening reaction, a combination of heat hardening reactions having different hardening starting temperatures, or a combination of light hardening reactions having different hardening wavelengths.

[0037] The combination of the curing reactions is not particularly limited, and for example, the combination described above may be used.

[0038] In such a case, for example, the at least two curing reactions may include a combination of at least two selected from the group consisting of a free radical curing system, a cationic curing system, an anionic curing system, an addition curing system, and a condensation curing system.

[0039] The combination of the curing reactions is not particularly limited, and for example, the combination described above may be used.

[0040] In addition, the present invention provides a laser induced forward transfer method, which transfers a microstructure formed on a supply substrate to a receiving substrate by laser lift-off, wherein:

[0041] The surface of the microstructure facing the receiving substrate has a protrusion,

[0042] The surface of the receiving substrate on which the microstructure is transferred has a curable resin layer.

[0043] By pressing the microstructure against the curable resin layer, the protrusion is buried in the curable resin layer.

[0044] The curable resin layer is cured while the protrusion is embedded in the curable resin layer, thereby holding the microstructure on the receiving substrate.

[0045] Laser lift-off is performed while the microstructure is held on the receiving substrate.

[0046] If this is the laser induced forward transfer method, laser stripping is performed in a state where the protrusions of the microstructure are buried in a hardening resin layer, so that local stress can be prevented from being applied to the microstructure during laser stripping. Therefore, in the laser induced forward transfer method of the present invention, even for a microstructure with protrusions, it is possible to transfer it from a supply substrate to a receiving substrate while preventing damage. In addition, the hardening resin layer of the receiving substrate used in the laser induced forward transfer method of the present invention can be hardened and hardened while the microstructure is maintained. Therefore, in the laser induced forward transfer method of the present invention, the positional deviation of the received microstructure can be suppressed and the microstructure can be maintained on the receiving substrate in an inclined manner.

[0047] In addition, the present invention provides a holding method for holding a microstructure having a protrusion on a receiving substrate, wherein:

[0048] The receiving substrate has a curable resin layer on the surface holding the microstructure.

[0049] By pressing the microstructure against the curable resin layer, the protrusion is buried in the curable resin layer.

[0050] The curable resin layer is cured in a state where the protrusions are buried in the curable resin layer, thereby holding the microstructure on the receiving substrate.

[0051] According to such a holding method, the microstructure can be held on the receiving substrate while preventing damage, positional displacement, and tilt of the microstructure by curing the curable resin layer while the protrusions of the microstructure are buried in the curable resin layer.

[0052] In addition, the present invention provides a method for cleaning a microstructure, wherein:

[0053] After the microstructure is transferred to the receiving substrate by the laser induced forward transfer method of the present invention, the microstructure is cleaned by an acidic cleaning solution or an alkaline cleaning solution.

[0054] As described above, in the laser induced forward transfer method of the present invention, the received microstructure can be kept on the receiving substrate while being shifted and tilted. Therefore, the cleaning method of the present invention can be used to prevent the microstructure from falling off, shifting and tilting.

[0055] In addition, the present invention provides a cleaning method for a microstructure having protrusions, wherein:

[0056] By pressing the microstructure against the curable resin layer, the protrusion is buried in the curable resin layer.

[0057] After the curable resin layer is cured, the microstructure is cleaned with an acidic cleaning solution or an alkaline cleaning solution in a state where the protrusions of the microstructure are covered with the resin layer without gaps and no bubbles exist in the resin layer within 5 μm around the protrusions.

[0058] If this is the cleaning method, after the protrusions of the microstructure are buried in the curable resin layer and the curable resin layer is hardened, the microstructure is cleaned in a state where the protrusions of the microstructure are covered with the resin layer without gaps and there are no bubbles in the resin layer within 5 μm around the protrusions. This can prevent the microstructure from falling off, positional displacement and tilting caused by cleaning.

[0059] Effects of the Invention

[0060] As described above, according to the receiving substrate of the present invention, the microstructure can be received by laser lift-off while suppressing damage, and the positional deviation and inclination of the microstructure can be suppressed.

[0061] Furthermore, according to the method for manufacturing a receiving substrate of the present invention, it is possible to manufacture a receiving substrate that can receive a microstructure by laser lift-off while suppressing damage and can suppress positional deviation and tilt of the microstructure.

[0062] In addition, the laser-induced forward transfer method of the present invention can transfer even a microstructure having a protrusion from a supply substrate to a receiving substrate while preventing damage. In addition, in the laser-induced forward transfer method of the present invention, the positional deviation and tilt of the received microstructure can be suppressed so that the microstructure is maintained on the receiving substrate.

[0063] Furthermore, according to the holding method of the present invention, the microstructure can be held on the receiving substrate while suppressing positional deviation and inclination of the microstructure.

[0064] In addition, according to the cleaning method of the present invention, the microstructure can be cleaned while preventing it from falling off, shifting, or tilting. BRIEF DESCRIPTION OF THE DRAWINGS

[0065] [ Figure 1 ] is a schematic diagram showing an example of a receiving substrate of the present invention.

[0066] [ Figure 2 ] is a schematic diagram showing an example of a method for manufacturing a receiving substrate of the present invention.

[0067] [ Figure 3 ] is a schematic diagram showing an example of a supply substrate that can be used in the present invention.

[0068] [ Figure 4 ] is a schematic diagram showing an example of the laser induced forward transfer method of the present invention.

[0069] [ Figure 5 ] is a schematic diagram showing bonding and secondary hardening in an example of laser induced forward transfer of the present invention.

[0070] [ Figure 6 ]yes Figure 5 (C) Detail image.

[0071] [ Figure 7 ]yes Figure 6 A schematic diagram of another side of the laminate substrate shown.

[0072] [ Figure 8 ] is a schematic diagram showing LLO and tearing in an example of the laser induced forward transfer method of the present invention.

[0073] [ Fig. 9 ] is a schematic diagram showing an example of the cleaning method of the present invention.

[0074] [ Fig.10 ] are photographs of the microstructure after transfer according to Example 1, the microstructure after peeling off following the transfer, and the microstructure after cleaning following the peeling off.

[0075] [ Fig.11 ] are photographs of the microstructure after transfer according to the reference example, the microstructure after peeling off following the transfer, and the microstructure after cleaning following the peeling off. DETAILED DESCRIPTION

[0076] As described above, it is required to develop a receiving substrate that can receive a microstructure while suppressing breakage and can hold the microstructure while suppressing positional displacement and tilt, a method for manufacturing such a receiving substrate, a laser induced forward transfer method that can transfer the microstructure from a supply substrate to a receiving substrate while suppressing breakage and can hold the microstructure while suppressing positional displacement and tilt, a holding method that can suppress positional displacement and tilt of the microstructure, and a cleaning method that can clean the microstructure while suppressing detachment, positional displacement and tilt.

[0077] The inventors of the present invention have repeatedly conducted diligent research on the above-mentioned subject and found that by using a receiving substrate including a curable resin layer as a receiving substrate, the microstructure can be received by laser peeling while suppressing damage, and the positional displacement and tilt of the microstructure can be suppressed, thereby completing the present invention.

[0078] That is, the present invention is a receiving substrate for transferring and receiving a microstructure formed on a supply substrate by laser lift-off, wherein the receiving substrate

[0079] A curable resin layer is provided on the surface on which the microstructure is transferred.

[0080] In addition, the present invention is a method for manufacturing a receiving substrate, wherein the receiving substrate has a curable resin layer, and the method for manufacturing the receiving substrate comprises:

[0081] A step of forming a layer of a resin capable of undergoing at least two curing reactions on one surface of a substrate for preparing a receiving substrate; and

[0082] A process of partially hardening the resin by performing a first hardening reaction.

[0083] In addition, the present invention is a laser induced forward transfer method, in which a microstructure formed on a supply substrate is transferred to a receiving substrate by laser lift-off, wherein:

[0084] The surface of the microstructure facing the receiving substrate has a protrusion,

[0085] The surface of the receiving substrate on which the microstructure is transferred has a curable resin layer.

[0086] By pressing the microstructure against the curable resin layer, the protrusion is buried in the curable resin layer.

[0087] The curable resin layer is cured while the protrusion is embedded in the curable resin layer, thereby holding the microstructure on the receiving substrate.

[0088] Laser lift-off is performed while the microstructure is held on the receiving substrate.

[0089] In addition, the present invention is a holding method for holding a microstructure having a protrusion on a receiving substrate, wherein:

[0090] The receiving substrate has a curable resin layer on the surface holding the microstructure.

[0091] By pressing the microstructure against the curable resin layer, the protrusion is buried in the curable resin layer.

[0092] The curable resin layer is cured in a state where the protrusions are buried in the curable resin layer, thereby holding the microstructure on the receiving substrate.

[0093] In addition, the present invention is a method for cleaning a microstructure, wherein:

[0094] After the microstructure is transferred to the receiving substrate by the laser induced forward transfer method of the present invention, the microstructure is cleaned by an acidic cleaning solution or an alkaline cleaning solution.

[0095] In addition, the present invention is a cleaning method, which is a cleaning method for a microstructure having protrusions, wherein:

[0096] By pressing the microstructure against the curable resin layer, the protrusion is buried in the curable resin layer.

[0097] After the curable resin layer is cured, the microstructure is cleaned with an acidic cleaning solution or an alkaline cleaning solution in a state where the protrusions of the microstructure are covered with the resin layer without gaps and no bubbles exist in the resin layer within 5 μm around the protrusions.

[0098] Hereinafter, the present invention will be described in detail, but the present invention is not limited to these descriptions.

[0099] [Receiving substrate]

[0100] Figure 1 An example of a receiving substrate of the present invention is schematically shown in FIG.

[0101] Figure 1 The receiving substrate 10 shown is a receiving substrate 10 for transferring and receiving a microstructure formed on a supply substrate by laser lift-off. The supply substrate and the microstructure will be described later.

[0102] like Figure 1 As shown, a curable resin layer 12 is provided on one surface 10A of the receiving substrate 10 (the surface on which the microstructure is transferred). Figure 1 The receiving substrate 10 of the example shown further comprises a supporting substrate 11 supporting a curable resin layer 12 .

[0103] The curable resin layer 12 is a layer of a curable resin, and may be in a first curing state, a B-stage state, or a semi-curing state.

[0104] The resin of such a hardening resin layer 12 can deform following the surface shape of the microstructure. If the hardening resin layer 12 is hardened (e.g., the second hardening), the resin of the hardening resin layer 12 can be hardened and maintained in a state of following the surface shape of the microstructure, so that even during laser lift-off (LLO), local stress can be prevented from being applied to the microstructure, and the microstructure can be firmly held. Therefore, if it is the receiving substrate 10 of the present invention, the microstructure can be received while suppressing damage, and positional displacement and tilting can also be prevented.

[0105] Hereinafter, the curable resin layer 12 and the supporting substrate 11 will be described in more detail.

[0106] <Hardening resin layer>

[0107] The resin of the curable resin layer 12 used in the present invention is not particularly limited as long as it is curable, and may be, for example, photocurable or thermocurable.

[0108] The resin of the curable resin layer 12 may be, for example, a two-step curing resin in a B-stage state. Such a resin layer 12 is subjected to a secondary curing process after receiving the microstructure, thereby being able to hold the microstructure without causing positional displacement or tilt.

[0109] The B-stage resin of the two-step curing type resin may be, for example, a composition obtained by subjecting a two-step curing type silicone composition to primary curing.

[0110] For example, a two-stage curing silicone composition is a silicone composition that can be cured in at least two stages by a combination of at least two curing reactions selected from addition curing reaction, photoradical polymerization reaction, thermal radical polymerization reaction, cationic curing reaction, anionic curing reaction and condensation curing reaction. The curing forms can be freely combined within the range that does not hinder the curing reaction. Among them, in terms of the ease of resin design or the ease of curing, it is preferred to use a combination of addition curing reaction and photoradical polymerization reaction, a combination of addition curing reaction and thermal radical polymerization reaction, and photoradical polymerization reaction and thermal radical polymerization reaction. In particular, in terms of the ease of design and the ease of curing, it is preferred to use a combination of addition curing reaction and photoradical polymerization reaction. There is no particular limitation as long as the at least two curing reactions are two or more, for example, it can be set to two or more and four or less.

[0111] After the coating process is performed on the support substrate 11, for example, when the first curing is performed by hydrosilylation reaction, it is preferably performed by heat curing at 20° C. to 200° C. for 5 minutes to 90 minutes, or when the first curing is performed by photo-radical polymerization reaction, it is preferably performed by heating at 50 mW / cm2 in a nitrogen environment with 365 nm light as an index. 2 ~3000mW / cm 2 The illumination is 100mJ / cm 2 ~20000mJ / cm 2 By irradiating the composition with ultraviolet rays or the like with an accumulated light amount of the above amount, a curable silicone resin layer after the first curing can be formed under curing conditions suitable for the silicone composition.

[0112] Here, the storage elastic modulus of the curable resin layer 12 after the first curing is preferably 10 Pa to 1000 Pa at 25° C., and particularly preferably 100 Pa to 500 Pa. A resin layer having a storage elastic modulus within the range of 10 Pa to 1000 Pa at 25° C. is different from a liquid state, and is easy to maintain in-plane uniformity, and the curable resin layer is easy to follow the unevenness of the microstructure.

[0113] When the obtained curable resin layer 12 is subjected to a second curing, for example, when the second curing is performed by a hydrosilation reaction, it is preferably heat-cured at 20° C. to 200° C. for 5 minutes to 90 minutes, or when the second curing is performed by a photo-radical polymerization reaction, it is preferably heated at 50 mW / cm2 in a nitrogen environment with 365 nm light as an index. 2 ~3000mW / cm 2 The illumination is 100mJ / cm 2 ~20000mJ / cm 2 By irradiating the composition with ultraviolet rays or the like with an accumulated light amount of the same as above, a second cured resin layer (eg, a silicone resin layer) can be formed under curing conditions suitable for the curable silicone composition.

[0114] Here, the curable resin layer 12 is preferably hardened (secondary hardening) so that the storage elastic modulus at 25°C becomes 1MPa to 30GPa, and more preferably becomes 4MPa to 5GPa. If the storage elastic modulus at 25°C after secondary hardening is 1MPa or more, the holding force of the microstructure can be fully ensured, for example, the falling off during cleaning can be fully suppressed. In addition, if the storage elastic modulus at 25°C after secondary hardening is 30GPa or less, a holding force sufficient to be applied to the next process can be presented.

[0115] The curable resin layer 12 is preferably in a gel state, such as a silicone gel layer. If it is a gel-like resin layer, it is possible to more reliably prevent the damage of the microstructure during laser peeling. In addition, in the present invention, the so-called gel state refers to a jelly-like state in which the liquid loses fluidity and has surface viscosity.

[0116] The curable resin layer 12 preferably has adhesiveness to the microstructure. If it is such a resin layer, the positional deviation of the received microstructure can be further prevented.

[0117] The hardness of the curable resin layer 12 is preferably increased by curing. If the hardness of the resin layer is increased by curing, the positional displacement or tilt of the microstructure can be further suppressed after curing.

[0118] Alternatively, the curable resin layer 12 preferably has an increased adhesive force to the microstructure or an increased holding force to the microstructure by curing. If such a resin layer is used, the positional displacement or tilt of the microstructure can be further suppressed after curing.

[0119] Alternatively, the curable resin layer 12 is also preferably made rubbery by curing. If it is a resin layer that becomes rubbery by curing, the positional displacement or tilt of the microstructure can be further suppressed after curing. In addition, in the present invention, the so-called rubbery refers to a state in which a repulsive force is shown to a load or impact and the elasticity or elasticity is excellent.

[0120] Furthermore, the curable resin layer 12 may be cured to become a cured resin such as a high-hardness plastic instead of a rubber-like state.

[0121] <Support substrate>

[0122] Examples of the support substrate 11 used for the receiving substrate 10 include a synthetic quartz glass substrate and float glass. In particular, a synthetic quartz glass substrate is preferred from the viewpoint of flatness and transparency.

[0123] In addition, the size of the support substrate 11 used in the receiving substrate 10 is preferably the same as or larger than the diameter of the supply substrate (described in detail below). Specifically, when a sapphire substrate with an outer diameter of 10.16 cm (4 inches) is used as the supply substrate, a receiving substrate 10 with an outer diameter of 10.16 cm to 20.32 cm (4 inches to 8 inches) can be used.

[0124] In order to reliably transfer part or all of the multiple microstructures from the supply substrate to the receiving substrate 10, in the bonding of the multiple microstructures formed on one surface of the supply substrate and the receiving substrate 10 provided with a curable resin layer 12 on the supporting substrate 11, it is preferred that each microstructure is temporarily and identically fixed to the curable resin layer 12 of the receiving substrate 10.

[0125] In order to temporarily fix the microstructure with good precision, the support substrate 11 used in the receiving substrate 10 is preferably: for an area of ​​6.01 mm×6.01 mm, the spatial frequency is 1 mm as measured by a white interferometer with a pixel number of 1240×1240. -1 The power spectral density above is 10 12 nm 4 In particular, when the microstructure is a micro-LED, considering the distance between the microstructures, it is preferred that the spatial frequency is 10 mm / s measured by a white interferometer with a pixel count of 1240×1240 for an area of ​​6.01 mm×6.01 mm. -1Above and 50mm -1 The power spectral density of the following is 10 9 nm 4 the following.

[0126] In addition, in order to temporarily fix the microstructure with good precision, the support substrate 11 used in the receiving substrate 10 preferably has a small thickness deviation. For example, the thickness deviation (total thickness variation (TTV)) measured by a wavelength conversion Fizeau flatness tester of Mizojiri Optical Industry Co., Ltd. is preferably 2 μm or less, more preferably 1 μm or less, and further preferably 0.5 μm or less.

[0127] Furthermore, the microstructure to be held by the receiving substrate 10 of the present invention may be a microstructure having protrusions or a microstructure without protrusions.

[0128] [Method for manufacturing receiving substrate]

[0129] The receiving substrate of the present invention can be obtained by referring to Figure 2 The receiving substrate of the present invention is manufactured by the manufacturing method of the receiving substrate of the present invention described below. However, the receiving substrate of the present invention can also be manufactured by a method other than the manufacturing method of the receiving substrate of the present invention described below.

[0130] First, if Figure 2 As shown in (A), a substrate (support substrate) 11 for receiving substrate production is prepared. The details of the support substrate used can be referred to the above description.

[0131] Then, if Figure 2 As shown in (B), a step of forming a layer 12a of a resin capable of undergoing at least two curing reactions on one surface of a supporting substrate 11 is performed to obtain a composite body 10a.

[0132] The process may include, for example, coating the support substrate 11 with a resin capable of undergoing at least two curing reactions.

[0133] The resin used here is not particularly limited as long as it can undergo at least two curing reactions. For example, the two-stage curing silicone composition described above can be used.

[0134] When the two-stage curing silicone composition shown above is used as a resin capable of undergoing at least two curing reactions, the two-stage curing silicone composition can be applied to the support substrate 11 in any shape by spin coating, slit coating or screen printing. The coating thickness of the two-stage curing silicone composition can be arbitrarily determined in consideration of the shape or thickness of the transferred microstructure, and is preferably 1 μm to 500 μm, more preferably 5 μm to 200 μm, and further preferably 10 μm to 100 μm from the perspective of ease of coating or maintaining uniformity of film thickness after curing. In addition, in order to improve the adhesion or bonding at the interface between the support substrate 11 and the curable silicone resin 12a, a support substrate 11 that has been pre-primed can also be used.

[0135] Next, a step is performed to partially cure the resin capable of at least two curing reactions in the resin layer 12a by performing a first curing reaction (so-called primary curing). Thus, the resin layer 12a is cured once to become a curable resin layer 12. As a result, a Figure 2 (C) shows the receiving substrate 10 of the present invention.

[0136] The curable resin layer 12 can be cured by secondary curing. Figure 2 (D) shows the second cured resin layer 12b. That is, Figure 2 The receiving substrate 10 b shown in (D) includes a supporting substrate 11 and a secondary cured resin layer 12 b formed on the supporting substrate 11 .

[0137] The at least two curing reactions (eg, primary curing and secondary curing) described above may include, for example, a combination of a light curing reaction and a heat curing reaction, a combination of heat curing reactions with different curing starting temperatures, or a combination of light curing reactions with different curing wavelengths.

[0138] On the other hand, the at least two curing reactions (eg, primary curing and secondary curing) described above may include, for example, a combination of at least two selected from the group consisting of free radical curing system, cationic curing system, anionic curing system, addition curing system, and condensation curing system.

[0139] [Laser-induced forward transfer method]

[0140] The laser induced forward transfer method of the present invention is a laser induced forward transfer method for transferring a microstructure formed on a supply substrate to a receiving substrate by laser lift-off. Figure 3 to Figure 8 An example of the laser induced forward transfer method of the present invention will be described.

[0141] As the receiving substrate used in the laser induced forward transfer method of the present invention, the receiving substrate 10 of the present invention described above can be used.

[0142] The supply substrate that can be used in the present invention is, for example, a supply substrate 20. Figure 3 As shown in FIG. 1 , a plurality of microstructures 100 are formed on one surface of the support substrate 21 , and a surface 100A of the microstructures 100 facing the receiving substrate 10 has a protrusion 130 . Figure 3 In the embodiment, protrusions 130 such as bumps are formed on the element body 120 of the microstructure 100. Recesses 110 are formed between the protrusions 130. In addition, a microstructure without protrusions can also be transferred by laser lift-off using the receiving substrate of the present invention described above.

[0143] Examples of the support substrate 21 used for the supply substrate 20 include a sapphire substrate, a GaAs substrate (gallium arsenide substrate), a Si substrate, and a SiC substrate, and the diameter thereof is arbitrary.

[0144] In addition, as the microstructure 100, for example, there can be listed elements obtained in the following manner: on a supporting substrate 21, after the basic structure of the device is prepared through processes performed in common semiconductor pre-processes such as epitaxial growth, ion implantation, wet etching, dry etching, evaporation, electrode formation, etc., the basic structure is separated by conventional methods such as blade dicing, dry etching, laser cutting, etc. until the depth of separating the elements is reached.

[0145] For example, in the case where the microstructure is an LED, an LED epitaxial substrate is prepared, wherein a buffer layer is provided on a 10.16 cm (4 inch) sapphire substrate, and after forming a 3 μm N-type GaN layer, a known light-emitting layer structure is provided, and the total thickness of the epitaxial layer formed by depositing P-type GaN is 4 μm. Then, after partially exposing the N layer by dry etching, a P-type electrode is formed on the P layer by a known process, and an N-type electrode is formed in contact with the exposed N layer, and a bump is formed on the electrode by plating, evaporation, or sputtering. Then, in order to separate LED elements of a specified size, laser cutting is performed in a manner that at least reaches the sapphire substrate and completely separates the elements, thereby obtaining a microstructure.

[0146] The size of the microstructure 100 is arbitrary, for example, in the case of a power LED, it is about 1 mm square. In addition, in the case of an LED element, it is about 300 μm square, in the case of a mini LED, it is about 100 μm square, in the case of a micro LED, it is about 60 μm square or less, and in the case of an extremely small micro LED, it is about 30 μm square or less.

[0147] In addition, the shape of the microstructure 100 described above is an example of a substantially square shape, but the present invention is not limited thereto. For example, in the case of a micro LED, the shape may be a rectangle with one side being 30 μm to 60 μm and the other side being 10 μm to 30 μm.

[0148] In addition, the thickness of the microstructure 100 depends on the thickness of the epitaxial growth on the supporting substrate 21 and is not particularly limited, but is preferably about 3 μm to 10 μm.

[0149] In the laser induced forward transfer method of the example, for example Figure 4 As shown in (A), the receiving substrate 10 and the supply substrate 20 are aligned with each other in such a way that the surface 10A of the receiving substrate 10 on which the curable resin layer 12 of the transfer microstructure 100 faces the protrusions 130 provided on the surface 100A of the supply substrate 20 on which the microstructure 100 is transferred.

[0150] Then, if Figure 4 As shown in (B), the microstructure 100 is pressed against the curable resin layer 12 so that the protrusions 130 are buried in the curable resin layer 12, thereby obtaining the laminated substrate 30. This step may also be called bonding.

[0151] Then, if Figure 4 As shown in (C), the curable resin layer 12 is cured while the protrusions 130 are embedded in the curable resin layer 12, thereby holding the microstructure 100 on the receiving substrate 10. This step may also be referred to as a second curing step.

[0152] In another example, the bonding of the plurality of microstructures 100 formed on one surface of the supply substrate 20 and the curable resin layer (eg, silicone resin layer) 12 on the receiving substrate 10 and the second curing can be performed as follows. Figure 5 In addition, Figure 5 In FIG. 1 , illustration of the protrusions of the microstructure 100 is omitted.

[0153] In the example described, Figure 5 (A) As shown in the alignment state, Figure 5As shown in (B), the entire receiving substrate 10 and the supply substrate 20 are laminated while being pressed so that the microstructure 100 on the supply substrate 20 and the curable resin layer 12 on the receiving substrate 10 face each other, thereby obtaining a laminated body 30.

[0154] Then, if Figure 5 As shown in (C), the curable resin layer 12 is subjected to a second curing to increase its hardness to form a second cured resin layer 12 b , thereby obtaining a laminated substrate 40 .

[0155] Figure 6 and Figure 7 Shown in Figure 5 (C) Details. Figure 7 It is for Figure 6 The microstructure 100 is observed through the supporting substrate 11 in a stacked substrate 40 in a state. The microstructure 100 transferred by the laser induced forward transfer method of the present invention has the protrusion 130 as described above. Figure 6 and Figure 7 In the embodiment, the protrusions 130 such as bumps are covered without gaps by the secondary cured resin layer 12b. Figure 3 The recessed portion 110 of the microstructure 100 shown is filled with the resin layer 12 b.

[0156] If there are no bubbles in the resin layer 12b within 5 μm around the protrusion 130, the protrusion 130 can be prevented from contacting the cleaning solution during the cleaning process, thereby preventing changes in the components constituting the protrusion 130. The absence of bubbles in the resin layer 12b within 5 μm from the protrusion 130 can be confirmed using, for example, a laser microscope.

[0157] The pressurization during lamination is preferably performed in a manner such that no bubbles remain between the curable resin layer 12 and the microstructure 100. For example, it is preferred to apply a load of preferably 0.05MPa to 1.0MPa, more preferably 0.10MPa to 0.5MPa for lamination. In addition, at this time, in order to make it easier for the curable resin layer 12 to follow the shape of the microstructure, pressurization can also be performed under reduced pressure. In addition, in the case where the second curing of the curable resin is produced by heating, heating can also be performed while laminating to perform the second curing.

[0158] Regarding the second curing of the curable resin layer 12, when the second curing is performed by hydrosilation reaction, it is preferably placed in a heating furnace at 80°C to 200°C for 5 minutes to 90 minutes, or when the second curing is performed by photoradical polymerization reaction, it is preferably performed in a nitrogen environment with 365nm light as an index at 50mW / cm 2 ~3000mW / cm2 The illumination is 100mJ / cm 2 ~20000mJ / cm 2 The composition is irradiated with ultraviolet rays or the like with an accumulated light amount equal to or greater than 10 %, thereby forming a second cured resin layer 12 b under curing conditions suitable for the curable silicone resin used.

[0159] Then, if Figure 4 (D) and Figure 8 As shown in (A) (the protrusions of the microstructure 100 are omitted), laser lift-off is performed using laser light L while the microstructure 100 is held on the receiving substrate 10. Laser lift-off performed in this state may also be referred to as contact laser lift-off (CLLO).

[0160] More specifically, the laminated substrate 40 obtained by the lamination and secondary curing process is irradiated with the laser light L formed by pulse oscillation, for example, from the surface of the supply substrate 20 opposite to the surface on which the microstructure 100 is formed, so that the microstructure 100 is peeled off from the supporting substrate 21. In this way, the microstructure 100 can be transferred from the supply substrate 20 to the second cured resin layer 12b on the receiving substrate 10.

[0161] In the LLO process, for example, when the microstructure 100 is a gallium nitride microstructure fixed on a support substrate 21 of a supply substrate 20 such as a sapphire substrate, the gallium nitride in the irradiated portion is melted by irradiation with laser light such as an excimer laser or a yttrium aluminum garnet (YAG) laser, thereby the gallium nitride microstructure 100 can be peeled off from the supply substrate 20. In such a case, in particular for micro LEDs, it is preferable to use KrF excimer laser light from the viewpoint of the reliability of the microstructure 100.

[0162] Specifically, laser light is selectively irradiated to generate laser ablation at the interface between the microstructure 100 as the selected object and the support substrate 21 of the supply substrate 20. Thus, between the microstructure 100 as the selected object and the support substrate 21 of the supply substrate 20, for example, in the case of a gallium nitride microstructure, gallium nitride is decomposed into metal gallium and nitrogen and generates gas, so that the microstructure 100 can be peeled off relatively easily.

[0163] After all the microstructures 100 to be transferred are irradiated with the same laser light L and transferred, for example, Figure 4 (E) and Figure 8As shown in (B) (the protrusion of the microstructure 100 is omitted), the receiving substrate 10b on which the microstructure 100 is transferred can be separated from the supporting substrate 21 of the supply substrate 20. Thus, the receiving substrate 10c holding the microstructure 100 can be obtained.

[0164] Since the supply substrate 20 and the microstructure 100 are separated by the LLO process, the supply substrate 20 can be easily separated by using an appropriate jig.

[0165] In the laser induced forward transfer method of the present invention as described above, laser stripping is performed in a state where the protrusion 130 of the microstructure 100 is buried in the curable resin layer 12, so that local stress can be prevented from being applied to the microstructure 100 during laser stripping. Therefore, in the laser induced forward transfer method of the present invention, even for a microstructure having a protrusion 130, it is possible to transfer it from a supply substrate to a receiving substrate while preventing damage. In addition, the curable resin layer 12 of the receiving substrate 10 used in the laser induced forward transfer method of the present invention can be hardened and hardened while the microstructure 100 is maintained. Therefore, in the laser induced forward transfer method of the present invention, the positional deviation and inclination of the received microstructure 100 can be suppressed so that the microstructure 100 is maintained on the receiving substrate 10.

[0166] The receiving substrate 10c may be used in the next process as it is, or may be used in the next process after being subjected to a cleaning process using an acid cleaning solution or an alkaline cleaning solution described later, or surface cleaning using oxygen plasma, argon plasma, or the like.

[0167] The microstructure 100 transferred to the receiving substrate 10c by the laser induced forward transfer method of the present invention or further by the cleaning method described later can be mounted on the circuit substrate through a desired process such as using a transfer stamp material described in Patent Document 1 or transferring the microstructure 100 to a polyimide layer again. That is, the receiving substrate 10c can also be used as a supply substrate (donor substrate) for supplying the microstructure 100 to other substrates in other processes.

[0168] [Maintenance method]

[0169] Figure 4 (B) and Figure 4 (C) and Figure 5The lamination and secondary curing shown can also be referred to as the holding method of the present invention. That is, the holding method of the present invention for holding the microstructure 100 having the protrusion 130 on the receiving substrate 10 is the following holding method: the surface of the receiving substrate 10 holding the microstructure 100 has a hardening resin layer 12, the microstructure 100 is pressed against the hardening resin layer 12 so that the protrusion 130 is embedded in the hardening resin layer 12, and the hardening resin layer 12 is hardened while the protrusion 130 is embedded in the hardening resin layer 12, thereby holding the microstructure 100 on the receiving substrate 10.

[0170] According to this holding method, the microstructure 100 can be held on the receiving substrate 10 while preventing damage, positional displacement, and tilt of the microstructure 100 by hardening the hardening resin layer 12 while the protrusions 130 of the microstructure 100 are buried in the hardening resin layer 12 .

[0171] In addition, if it is the receiving substrate of the present invention described previously, even for a microstructure without protrusions, the microstructure without protrusions can be maintained on the receiving substrate of the present invention by secondary curing of the curable resin layer while pressing the contact surface of the microstructure into the curable resin layer.

[0172] [Cleaning method]

[0173] In one aspect of the cleaning method of the present invention, after the microstructure 100 is transferred to the receiving substrate 10 by the above-described peeling method of the present invention, the microstructure 100 is cleaned by an acidic cleaning solution or an alkaline cleaning solution.

[0174] In another aspect, the cleaning method of the present invention is, for example, Figure 3 The cleaning method of the microstructure 100 having the protrusion 130 shown in FIG. Figure 5 As shown in (B), the microstructure 100 is pressed against the curable resin layer 12 so that the protrusions 130 are buried in the curable resin layer 12, for example, Figure 6 and Figure 7 As shown, after the curable resin layer 12 is cured, the microstructure 100 is cleaned using an acidic cleaning solution or an alkaline cleaning solution in a state where the protrusions 130 of the microstructure are covered with the resin layer 12b without gaps and there are no bubbles in the resin layer 12b within 5 μm around the protrusions 130.

[0175] Hereinafter, the cleaning method of the present invention will be described in more detail.

[0176] Fig. 9 As an example of the cleaning method of the present invention, Figure 8As shown in the figure, the LLO process is completed and the metal Ga is cleaned after stripping.

[0177] exist Fig. 9 In (A), on the receiving substrate 10c after the LLO process, there is a second cured resin layer 12b holding the microstructure 100, and a metal (e.g., Ga) 140 is attached to the surface of the microstructure 100 opposite to the resin layer 12b. Here, since the interface between the resin layer 12b and the microstructure 100 is in a close contact state, the entire receiving substrate 10 is immersed or rinsed with an acidic cleaning solution or an alkaline cleaning solution in this state, thereby Fig. 9 As shown in (B), the metal 140 is dissolved and removed, and a receiving substrate 10d on which the microstructure is transferred and held is obtained. At this time, the interface on the resin layer 12b side of the microstructure 100 is covered and held by the resin layer 12b, so it will not be affected by the acidic cleaning solution or the alkaline cleaning solution, and will not be distilled away in the cleaning process. The receiving substrate 10d is then carefully cleaned with pure water and dried by air drying, etc., and is thus used in the next process.

[0178] In these cleaning steps, the microstructure 100 is held by the resin layer 12b, and does not fall off from the surface of the resin layer 12b and remain. In addition, positional deviation or tilting can also be suppressed by being held by the resin layer 12b.

[0179] Especially in Fig. 9 In the example shown, since the protrusion 130 of the microstructure 100 is entirely covered with the resin layer 12b without gaps and there are no bubbles in the resin layer 12b within 5 μm around the protrusion 130, the protrusion 130 can be prevented from being affected by acid or alkali during the cleaning process.

[0180] Furthermore, the cleaning process is carried out in a state where there is no air layer with a maximum length of more than 1 μm at the interface between the resin layer 12b and the component body 120 and the protrusion 130, and the components are in close contact with each other. This prevents the composition of the interface on the resin layer 12b side of the component body 120 and the composition of the bump when the protrusion 130 is a bump from being affected, so that the component can be used in the next process without any problems.

[0181] Regarding the cleaning solution in this cleaning step, in the case of an acid cleaning solution, a solution obtained by uniformly mixing concentrated hydrochloric acid, concentrated nitric acid, concentrated sulfuric acid, etc. with pure water in an arbitrary ratio may be used, or a plurality of acid aqueous solutions may be used. At this time, the pH of the cleaning solution is preferably 0 to 4.0. If the pH is within this range, sufficient solubility for the metal (e.g., Ga) 140 can be utilized.

[0182] In the case of an alkaline cleaning solution, sodium hydroxide, potassium hydroxide, ammonium hydroxide, magnesium hydroxide, tetramethylammonium hydroxide, tetrabutylammonium hydroxide, sodium carbonate, sodium bicarbonate, and potassium acetate may be dissolved in pure water at any concentration, or a plurality of alkaline cleaning solutions may be used. In this case, the pH of the cleaning solution is preferably 9.5 to 14.0. If the pH is within this range, sufficient solubility for the metal (e.g., Ga) 140 can be utilized.

[0183] As described above, if it is the receiving substrate of the present invention, a microstructure without protrusions can also be held. Therefore, in a modified example of the cleaning method of the present invention, a microstructure without deletion protrusions can also be cleaned while being held by the receiving substrate of the present invention.

[0184] The present invention described above is particularly applicable to the manufacturing process of LED displays for use in signage, TV, medical, vehicle, smartphones, and the like.

[0185] Example

[0186] Hereinafter, the present invention will be specifically described using Examples and Comparative Examples, but the present invention is not limited thereto.

[0187] Supply substrates including the following microstructures were prepared respectively.

[0188] <Supplying substrate A and microstructure A>

[0189] A sapphire substrate cut into 1.5 cm squares and equipped with a 90 μm × 140 μm mini LED element with a total thickness of 19 μm and a bump height of 7 μm.

[0190] <Supplying substrate B and microstructure B>

[0191] A sapphire substrate cut into 1.5 cm squares and equipped with a micro LED element measuring 18 μm x 36 μm, with a total thickness of 9 μm and a bump height of 4 μm.

[0192] In addition, the following substrates were prepared as support substrates for receiving substrates.

[0193] <Support substrate for receiving substrate>

[0194] Synthetic quartz substrate with an outer diameter of 15.24 cm (6 inches), a thickness of 1 mm, and a thickness deviation (TTV) of 0.8 μm

[0195] <Experimental contents: Examples 1 to 5>

[0196] [Production of receiving substrate]

[0197] 3 g of the following two-stage curing silicone resin composition (Silicone A or Silicone B) was dripped onto the supporting substrate, and the coating was evenly applied onto the supporting substrate using a spin coater in a manner such that the film thickness was 30 μm. The obtained coating was subjected to the following first curing conditions to cure the silicone resin composition once and make it gel-like, thereby preparing a receiving substrate having a curable silicone resin.

[0198] [Fitting]

[0199] The supply substrate and the receiving substrate were bonded together while being pressurized at 0.5 MPa in such a manner that the microstructure on the supply substrate and the curable silicone resin on the receiving substrate, as shown in Table 1 below, were in contact. Then, the curable silicone resin was secondary cured under the conditions shown below. Then, using a laser microscope, it was confirmed whether there was an air layer of at least 1 μm in length between the supply substrate and the microstructure and the secondary cured silicone resin, and whether there were no bubbles in the resin within 5 μm around the protrusion.

[0200] [LLO and tear off]

[0201] Next, the microstructures were irradiated with KrF excimer laser light from the back side of the supply substrate to perform LLO. Thereafter, the supply substrate was separated from the receiving substrate.

[0202] After the peeling, the transfer rate and breakage rate of the microstructure from the supply substrate to the receiving substrate were evaluated. The results are shown in Table 1 below.

[0203] Then, the surface of the microstructure was cleaned by immersing it for 3 minutes in an acid cleaning solution or an alkaline cleaning solution shown below and in Table 1. Subsequently, the step of immersing it in pure water for 3 minutes was repeated twice, and then it was dried by air drying.

[0204] After drying by air drying, the microstructure was checked for tilting and falling off. The results are shown below.

[0205] Acidic cleaning liquid: 12 mass% hydrochloric acid aqueous solution

[0206] Alkaline cleaning solution: 5% potassium hydroxide aqueous solution

[0207] [Determination of elastic modulus]

[0208] The dynamic viscoelastic properties of the cured silicone gel in the present invention are defined by the characteristic frequency and the storage elastic modulus G' at a specific temperature, and the measurement is performed using the viscoelasticity measuring device ARES G-II manufactured by TA Instruments. The silicone resin cured and formed into a 3 cm square and 500 μm thick is clamped between the circular shape measuring part of the testing machine and the parallel plate with a diameter of 20 mm in a manner that does not contain bubbles, and the temperature is maintained at 25°C while the strain value is set to 4% and the frequency is set to 1 Hz for 10 minutes. The value read 10 minutes after the start of the measurement is taken as the storage elastic modulus G'. The silicone resin after the second curing is also measured using the same process and conditions. The results are shown below.

[0209] Silicone A: A two-stage curing silicone composition, which undergoes a first curing by an addition reaction at 120°C for 1 h to form a gel with a storage elastic modulus G' of 0.2 kPa. Then, the silicone composition is irradiated with a 365 nm ultraviolet (UV)-LED at 3000 mJ / cm2 under nitrogen. 2 (Illuminance: 100mW / cm 2 ) to undergo a photo-radical reaction and undergo a second hardening, becoming a rubbery material with a storage elastic modulus G' of 8.2 MPa.

[0210] Silicone B: A two-stage curing silicone composition, which was cured by irradiation with a 365 nm UV-LED at 3000 mJ / cm 2 (Illuminance: 100mW / cm 2 ) is first cured by photo-radical reaction to become a gel with a storage elastic modulus G' of 5 kPa, and then secondly cured by addition reaction at 120°C × 1h to become a rubber with a storage elastic modulus G' of 4 GPa.

[0211] <Experimental contents: Comparative Examples 1 to 4>

[0212] The receiving substrate was prepared by hardening the silicone composition (Silicone C) shown below into a rubber state under a single curing condition, and the transfer rate, breakage rate and positional deviation of the microstructure in the LLO process and the presence or absence of tilting and falling of the microstructure in the cleaning process were confirmed by the same process as in the example. That is, the receiving substrates used in Comparative Examples 1 to 4 do not have a curable resin layer.

[0213] The elastic modulus of silicone C cured into a rubbery state was measured according to the procedure shown above.

[0214] Silicone C: A heat-curable silicone composition that cures by addition reaction at 120°C for 1 hour to form a rubber-like material with a storage elastic modulus G' of 4.7 MPa.

[0215]

[0216] in addition, Fig.10 The microstructure after transfer by LLO in Example 1 is shown in FIG. Fig.10 (A)), the microstructure after tearing off after the transfer ( Fig.10 (B)), and the microstructure after cleaning following the tearing ( Fig.10 (C))Photo.

[0217] The microstructures after transfer by LLO, the microstructures after separation after transfer, and the microstructures after cleaning after separation in each of Examples 2 to 5 are also similar to those in Examples 2 to 5. Fig.10 (A) Fig.10 (B) and Fig.10 (C) is the same as shown.

[0218] As shown in Table 1 and Fig.10 As clearly shown, in Examples 1 to 5, the microstructure having protrusions can be transferred from the supply substrate to the receiving substrate at a transfer rate of 99% or more without damage or positional deviation.

[0219] In addition, according to the results shown in Table 1 and Fig.10 As is clear, in Examples 1 to 5, no falling off or tilting of the microstructure was observed after cleaning.

[0220] These results are based on the following: in Examples 1 to 5, the once-hardened silicone resin layer receives the microstructure in a state where the protrusions of the microstructure are embedded in the once-hardened silicone resin layer, and the silicone resin layer is secondarily hardened in the said state to achieve high hardness, whereby the secondarily-hardened silicone resin layer can fully retain the microstructure, thereby preventing the microstructure from being damaged, falling off, shifting in position and tilting during the transfer, tearing off and cleaning processes performed by LLO.

[0221] On the other hand, in Comparative Examples 1 to 4, since a hardened rubber substrate was used instead of a receiving substrate having a hardening resin layer, the breakage rate was 5% or more. In addition, positional displacement of the microstructure was also confirmed in Comparative Examples 1 and 2. In addition, as is clear from the results shown in Table 1, in Comparative Examples 1 to 4, tilting of the microstructure was observed after cleaning.

[0222] Furthermore, as a reference example, LLO, peeling, and cleaning were performed in the same manner as in Example 1 except that the secondary curing of the curable resin layer was not performed during LLO. Fig.11 The microstructure after transfer by LLO in the reference example is shown in FIG. Fig.11 (A)), the microstructure after tearing off after the transfer ( Fig.11 (B)), and the microstructure after cleaning following the tearing ( Fig.11 (C))Photo.

[0223] In the reference example, the position of the microstructure was shifted during LLO, and the transfer rate was low. Furthermore, in the reference example, the microstructure that was not placed on the silicone resin layer after secondary curing was cracked during LLO.

[0224] In addition, in the reference example, according to Fig.11 (B) and Fig.11 (C) As is clear from the above, the falling off, positional displacement or tilting of the microstructure due to the peeling and washing was observed.

[0225] This manual includes the following aspects.

[0226] [1] A receiving substrate for transferring and receiving a microstructure formed on a supply substrate by laser lift-off, wherein the receiving substrate has a curable resin layer on a surface on which the microstructure is transferred.

[0227] [2] The receiving substrate according to [1], wherein the curable resin layer is photocurable or thermocurable.

[0228] [3] The receiving substrate according to [1] or [2], wherein the curable resin layer is in a B-stage state.

[0229] [4] The receiving substrate according to any one of [1] to [3], wherein the curable resin layer is in a gel state.

[0230] [5] The receiving substrate according to any one of [1] to [4], wherein the curable resin layer is a silicone gel layer.

[0231] [6] The receiving substrate according to any one of [1] to [5], wherein the curable resin layer has adhesion to the microstructure.

[0232] [7] The receiving substrate according to any one of [1] to [6], wherein the curable resin layer increases in hardness by curing.

[0233] [8] The receiving substrate according to any one of [1] to [7], wherein the curable resin layer increases its adhesive force to the microstructure or increases its holding force to the microstructure by curing.

[0234] [9] The receiving substrate according to any one of [1] to [8], wherein the curable resin layer becomes rubber-like by curing.

[0235]

[10] The receiving substrate according to any one of [1] to [9], wherein the storage elastic modulus of the curable resin layer is 10 Pa to 1000 Pa at 25° C. and becomes 1 MPa to 30 GPa by curing.

[0236]

[11] A method for manufacturing a receiving substrate, the receiving substrate having a curable resin layer, the method comprising: a step of forming a layer of a resin capable of undergoing at least two curing reactions on one surface of a substrate for manufacturing the receiving substrate; and a step of locally curing the resin by undergoing a first curing reaction.

[0237]

[12] The method for manufacturing a receiving substrate according to

[11] , wherein the at least two hardening reactions include a combination of a photohardening reaction and a thermal hardening reaction, a combination of thermal hardening reactions with different hardening starting temperatures, or a combination of photohardening reactions with different hardening wavelengths.

[0238]

[13] A method for manufacturing a receiving substrate according to

[11] or

[12] , wherein the at least two hardening reactions include a combination of at least two selected from the group consisting of a free radical hardening system, a cationic hardening system, an anionic hardening system, an addition hardening system and a condensation hardening system.

[0239]

[14] A laser induced forward transfer method, in which a microstructure formed on a supply substrate is transferred to a receiving substrate by laser stripping. In the laser induced forward transfer method, the surface of the microstructure facing the receiving substrate has a protrusion, and the surface of the receiving substrate on which the microstructure is transferred has a curable resin layer. The microstructure is pressed against the curable resin layer so that the protrusion is buried in the curable resin layer, and the curable resin layer is hardened while the protrusion is buried in the curable resin layer, thereby maintaining the microstructure on the receiving substrate, and laser stripping is performed while the microstructure is maintained on the receiving substrate.

[0240]

[15] A holding method for holding a microstructure having a protrusion on a receiving substrate, wherein the receiving substrate has a hardenable resin layer on the surface holding the microstructure, and the microstructure is pressed against the hardenable resin layer so that the protrusion is buried in the hardenable resin layer, and the hardenable resin layer is hardened while the protrusion is buried in the hardenable resin layer, thereby holding the microstructure on the receiving substrate.

[0241]

[16] A method for cleaning a microstructure, wherein after the microstructure is transferred to the receiving substrate by the peeling method according to

[14] , the microstructure is cleaned using an acidic cleaning solution or an alkaline cleaning solution.

[0242]

[17] A cleaning method is a cleaning method for a microstructure having a protrusion, wherein the microstructure is pressed against a curable resin layer so that the protrusion is buried in the curable resin layer. After the curable resin layer is cured, the microstructure is cleaned using an acidic cleaning solution or an alkaline cleaning solution in a state where the protrusion of the microstructure is seamlessly covered by the resin layer and no bubbles exist in the resin layer within 5 μm around the protrusion.

[0243] The present invention is not limited to the above-described embodiments. The above-described embodiments are merely examples, and any form having substantially the same structure and achieving the same function and effect as the technical concept described in the claims of the present invention is included in the technical scope of the present invention.

Claims

1. A receiving substrate for transferring and receiving a microstructure formed on a supply substrate by laser lift-off, wherein: A curable resin layer is provided on the surface on which the microstructure is transferred.

2. The receiving substrate according to claim 1, in, The curable resin layer is photocurable or thermocurable.

3. The receiving substrate according to claim 1, in, The curable resin layer is in a B-stage state.

4. The receiving substrate according to claim 1, in, The curable resin layer is in a gel state.

5. The receiving substrate according to claim 1, in, The curable resin layer is a silicone gel layer.

6. The receiving substrate according to claim 1, in, The curable resin layer has adhesion to the microstructure.

7. The receiving substrate according to claim 1, in, The hardness of the curable resin layer increases as it cures.

8. The receiving substrate according to claim 1, in, The curable resin layer improves its adhesive force to the microstructure or its holding force to the microstructure by curing.

9. The receiving substrate according to claim 4, in, The curable resin layer becomes rubber-like by curing.

10. The receiving substrate according to claim 4, in, The storage elastic modulus of the curable resin layer is 10 Pa to 1000 Pa at 25° C., and becomes 1 MPa to 30 GPa by curing.

11. A method for manufacturing a receiving substrate, the receiving substrate having a curable resin layer, the method for manufacturing the receiving substrate comprising: A step of forming a layer of a resin capable of undergoing at least two curing reactions on one surface of a substrate for preparing a receiving substrate; and A process of partially hardening the resin by performing a first hardening reaction.

12. The method for manufacturing a receiving substrate according to claim 11, in, The at least two hardening reactions include a combination of a light hardening reaction and a heat hardening reaction, a combination of heat hardening reactions having different hardening starting temperatures, or a combination of light hardening reactions having different hardening wavelengths.

13. The method for manufacturing a receiving substrate according to claim 11, in, The at least two hardening reactions include a combination of at least two selected from the group consisting of a free radical hardening system, a cationic hardening system, an anionic hardening system, an addition hardening system, and a condensation hardening system.

14. A laser induced forward transfer method, wherein a microstructure formed on a supply substrate is transferred to a receiving substrate by laser lift-off, wherein: The surface of the microstructure facing the receiving substrate has a protrusion, The surface of the receiving substrate on which the microstructure is transferred has a curable resin layer. By pressing the microstructure against the curable resin layer, the protrusion is buried in the curable resin layer. The curable resin layer is cured while the protrusion is embedded in the curable resin layer, thereby holding the microstructure on the receiving substrate. Laser lift-off is performed while the microstructure is held on the receiving substrate.

15. A holding method for holding a microstructure having a protrusion on a receiving substrate, wherein: The receiving substrate has a curable resin layer on the surface holding the microstructure. By pressing the microstructure against the curable resin layer, the protrusion is buried in the curable resin layer. The curable resin layer is cured in a state where the protrusions are buried in the curable resin layer, thereby holding the microstructure on the receiving substrate.

16. A method for cleaning a microstructure, in, After the microstructure is transferred to the receiving substrate by the laser induced forward transfer method according to claim 14, the microstructure is cleaned by using an acidic cleaning solution or an alkaline cleaning solution.

17. A cleaning method for a microstructure having protrusions, in, By pressing the microstructure against the curable resin layer, the protrusion is buried in the curable resin layer. After the curable resin layer is cured, the microstructure is cleaned with an acidic cleaning solution or an alkaline cleaning solution in a state where the protrusions of the microstructure are covered with the resin layer without gaps and no bubbles exist in the resin layer within 5 μm around the protrusions.

Images