Substrate for transferring microstructure and method for manufacturing the same

Abstract

The present invention relates to a substrate for transferring a microstructure and a manufacturing method thereof. A substrate for transferring a microstructure (e.g., a micro LED) having an engraved mark is provided. The substrate for transferring a microstructure is less likely to cause a reading error of the engraved mark occurring in a reading device, and is capable of stably and continuously reading the engraved mark. A substrate for transferring a microstructure includes a synthetic quartz glass substrate, and an organic silicon pressure-sensitive adhesive layer disposed on a front surface of the synthetic quartz glass substrate. The front surface of the substrate is provided with an engraved mark.

Description

[0001] Cross-reference related applications

[0002] Pursuant to 35 USC §119(a), this non-provisional application claims priority to Japanese Patent Application No. 2020-085108, filed on May 14, 2020, the entire contents of which are incorporated herein by reference. Technical Field

[0003] The present invention relates to a substrate for transferring microstructures and a method thereof, and more specifically, to a substrate having an identification laser imprint in a substrate for transferring microstructures (e.g., micro light-emitting diodes (hereinafter also referred to as “micro LEDs”), and a method thereof. Background Technology

[0004] In recent years, electronic devices (such as smartphones, LCD displays, and automotive components) have demanded not only high performance but also space-saving and energy-efficient design. Simultaneously, the electrical and electronic components they incorporate are becoming increasingly miniaturized and micro-sized. The assembly processes for these components are also becoming more complex year by year.

[0005] Patent Document 1 discloses a method for transferring microstructures and micro-elements (e.g., micro-LEDs). This method enables the transfer of microstructures with high precision and efficiency while they are temporarily fixed to a donor substrate, without increasing the number of steps.

[0006] To manage substrates flowing through the production line, lasers are typically used to directly engrave text and numbers onto the substrates. For example, non-patent literature 1 defines a standard for laser-engraved markings on substrates. These markings are widely used because they are useful for reading information for quality management and for managing the frequency and consumption of products after they leave the warehouse.

[0007] Existing technical documents

[0008] Patent documents

[0009] Patent Document 1: JP-A 2002-118124

[0010] Non-patent literature

[0011] Non-Patent Document 1: SEMI T7 0303 Specifications for Double-Sided Polishing Wafer Back Surface Marking of Two-Dimensional Matrix Code Symbol, North American Traceability Committee, issued March 2003. Summary of the Invention

[0012] However, in the substrate for transferring microstructures with a pressure-sensitive adhesive layer described in Patent Document 1, resin is bonded or coated after etching. Therefore, when etching the substrate, the back side of the substrate is usually etched. However, the back side of the substrate is prone to getting dirty or scratched due to contact with protrusions around the etched mark, which may result in the inability to read the engraved mark continuously and stably.

[0013] The present invention was made in view of the above circumstances, and its object is to provide a substrate with etched markings for transferring microstructures (e.g., micro-LEDs). This substrate for transferring microstructures is less prone to errors in recognizing the etched markings in a reading device and enables stable and continuous reading of the etched markings.

[0014] In order to achieve the above objectives, the inventors conducted in-depth research and found that a synthetic quartz glass substrate for transferring microstructures, having an etched mark disposed on the front side (front surface) of the substrate and an organosilicon pressure-sensitive adhesive layer disposed thereon, can solve the above problems and thus complete the present invention.

[0015] That is, the present invention provides the following 1 to 7:

[0016] 1. A substrate for transferring microstructures, comprising: a synthetic quartz glass substrate, and an organosilicon pressure-sensitive adhesive layer disposed on the front side of the synthetic quartz glass substrate, wherein the substrate has etched markings on the front side.

[0017] 2. The substrate for transferring microstructures according to claim 1, wherein the aforementioned synthetic quartz glass substrate is at a spatial frequency of 1 mm. -1 The above power spectral density is 10 12 nm 4 The power spectral density was obtained by measuring a 6.01 mm × 6.01 mm area on the front and back sides of the synthetic quartz glass substrate using a white light interferometer with a pixel count of 1240 × 1240.

[0018] 3. The substrate for transferring microstructures according to 1 or 2, wherein the surface roughness (Ra) of the back side of the synthetic quartz glass substrate is less than 0.05 μm.

[0019] 4. The substrate for transferring microstructures according to any one of 1 to 3, wherein the above-mentioned imprinted mark is a laser mark with a depth of 3 to 25 μm and a dot size of 20 to 200 μm.

[0020] 5. A method for manufacturing a substrate for transferring microstructures, comprising the steps described in any one of 1 to 4, wherein the method includes the following steps:

[0021] The process of setting engraving marks on the front side of a synthetic quartz glass substrate to obtain a synthetic quartz glass substrate with engraving marks, and

[0022] The process of setting an organosilicon pressure-sensitive adhesive layer on the front side of the synthetic quartz glass substrate with the above-mentioned etched markings.

[0023] 6. The method for manufacturing a substrate for transferring microstructures according to claim 5, wherein the step of providing the silicone pressure-sensitive adhesive layer is the following step: applying a silicone pressure-sensitive adhesive composition to the front side of a synthetic quartz glass substrate having etched markings, and then curing it.

[0024] 7. The method for manufacturing a substrate for transferring microstructures according to claim 5, wherein the step of providing the silicone pressure-sensitive adhesive layer is the following step: bonding a cured product formed by the silicone pressure-sensitive adhesive composition to the front side of a synthetic quartz glass substrate having etched markings.

[0025] Invention Effects

[0026] The substrate for transferring microstructures of the present invention has etched marks provided on the front side of the substrate, thereby suppressing dirt and scratches generated on the etched mark portion, thus enabling stable reading of the etched marks. Attached Figure Description

[0027] Figure 1 A and 1B are diagrams illustrating a substrate for transferring microstructures according to a first embodiment of the present invention; Figure 1 A is a side view. Figure 1 B is the top view.

[0028] Figure 2 A and 2B are diagrams illustrating a substrate for transferring microstructures according to a second embodiment of the present invention; Figure 2 A is a side view. Figure 2 B is the top view. Detailed Implementation

[0029] The present invention will now be described in more detail.

[0030] [1] Substrate for transferring microstructures

[0031] like Figure 1 The first embodiment shown in A and 1B and Figure 2 As shown in the second embodiment in A and 2B, the substrate for transferring microstructures of the present invention includes: a synthetic quartz glass substrate 10, and an organosilicon pressure-sensitive adhesive layer 20 disposed on the front side 11 of the synthetic quartz glass substrate 10. Identification marks 12 are applied to the front side 11 of the substrate 10.

[0032] In this invention, from the viewpoint of suppressing misalignment during the transfer of microstructures and thus improving transfer accuracy, it is necessary to use a synthetic quartz glass substrate (a material with a low coefficient of thermal expansion) as the base material for the transfer substrate.

[0033] There are no particular restrictions on the shape of the synthetic quartz glass substrate used. For example, depending on the application, a circular plate as used in the first embodiment (see reference) can be used. Figure 1 B) The square plate used in the second embodiment (refer to) Figure 2 B) Suitable shapes, etc.

[0034] There are no particular restrictions on the size of the synthetic quartz glass substrate; for example, a circular plate with a diameter of 3mm to 300mm can be used (e.g., Figure 1 (A and 1B), and square plate shapes with diagonal lengths of 3mm to 300mm (e.g., Figure 2 (A and 2B), etc.

[0035] Furthermore, there are no particular limitations on the thickness. From the viewpoint of suppressing bending during component transfer, it is preferable to be 0.5 mm to 5.0 mm, and more preferably 1 mm to 3 mm.

[0036] In this invention, there is no particular limitation on the flatness of the front side of the synthetic quartz glass substrate. From the viewpoint of improving transfer accuracy, SORI ≤ 10 μm is preferred, SORI ≤ 5 μm is more preferred, and SORI ≤ 2 μm is even more preferred.

[0037] There are no particular restrictions on the variation (uniformity) of thickness. From the same point of view, it is preferred to be 10 μm or less, more preferably 5 μm or less, and even more preferably 1 μm or less.

[0038] SORI (Smoothness and Rigidity) is a specification defined in SEMI (Self-Evaluation and Measurement Instrument). Variations in flatness and thickness can be measured using optical interferometers or laser displacement meters.

[0039] From the perspective of maintaining the transfer accuracy of microstructures, the front side of the synthetic quartz glass substrate has a spatial frequency of 1mm. -1 The preferred power spectral density is 10. 12 nm 4 The power spectral density was obtained by measuring a 6.01mm × 6.01mm region with 1240 × 1240 pixels using a white light interferometer. Specifically, considering the distance between the microstructures, for example, when the microstructures are micro-LEDs, at a spatial frequency of 10mm... -1 Above and 50mm -1 The following power spectral density is preferably 10 9 nm 4 The power spectral density was obtained by measuring a 6.01mm × 6.01mm area using a white light interferometer with a pixel count of 1240 × 1240.

[0040] Furthermore, there are no particular limitations on the surface roughness (Ra) of the back side of the synthetic quartz glass substrate, but it is preferably 0.05 μm or less, more preferably 0.01 μm or less. This range makes it easier to ensure transparency and reduces the possibility of reading errors caused by the reading device.

[0041] In the substrate for transferring microstructures of the present invention, in order to temporarily fix the microstructures with high precision, it is also very important to consider the accuracy of the thickness variation of the laminate of the synthetic quartz glass substrate and the silicone pressure-sensitive adhesive layer disposed on its front side.

[0042] There are no particular restrictions on the variation of the thickness of the laminate, but it is preferably 12 μm or less, more preferably 6 μm or less, and even more preferably 2 μm or less.

[0043] The silicone pressure-sensitive adhesive layer on the substrate for transferring microstructures of the present invention is preferably formed from a UV-curable silicone pressure-sensitive adhesive composition comprising the following components (A) to (D) and free from non-crosslinked organopolysiloxane resins.

[0044] By using this composition, instant bonding can be achieved, and peeling can be performed without producing so-called adhesive residue upon removal, thus facilitating the transfer of tiny structures with high precision.

[0045] (A) 100 parts by mass of an organopolysiloxane having two groups represented by the following general formula (1) in one molecule:

[0046]

[0047] Among them, R 1The groups independently represent monovalent hydrocarbon groups with 1 to 20 carbon atoms, preferably monovalent hydrocarbon groups with 1 to 10 carbon atoms (excluding aliphatic unsaturated groups), more preferably monovalent hydrocarbon groups with 1 to 8 carbon atoms; R 2 R represents an alkylene group having 1 to 20 oxygen or carbon atoms, preferably 1 to 10, and more preferably 1 to 5; 3 The terms "acryloyloxyalkyl", "methacryloyloxyalkyl", "acryloyloxyalkoxy", or "methacryloyloxyalkoxy" are mutually independent; "p" represents a number satisfying 0 ≤ p ≤ 10, and "a" represents a number satisfying 1 ≤ a ≤ 3.

[0048] (B) 1 to 200 parts by weight of monofunctional (meth)acrylate compounds without siloxane structures,

[0049] (C) 1 to 1000 parts by weight of an organopolysiloxane resin, which is composed of the following (a) to (c):

[0050] (a) A unit having the following general formula (2):

[0051]

[0052] Among them, R 1 R 2 R 3 a and p represent the same meaning as above.

[0053] (b)R 4 3SiO 1 / 2 Unit (where R) 4 (representing monovalent hydrocarbon groups with 1 to 10 carbon atoms), and

[0054] (c)SiO 4 / 2 unit,

[0055] Furthermore, the molar ratio of the total of units (a) and (b) to that of unit (c) is in the range of 0.4 to 1.2:1.

[0056] (D) 0.01 to 20 parts by weight of photopolymerization initiator.

[0057] The above monovalent hydrocarbon groups R with 1 to 20 carbon atoms 1 It can be straight-chain, branched, or cyclic. Examples include: alkyl groups such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl, n-hexyl, cyclohexyl, n-octyl, 2-ethylhexyl, and n-decyl; alkenyl groups such as vinyl, allyl (2-propenyl), 1-propenyl, isopropenyl, and butenyl; aryl groups such as phenyl, tolyl, xylyl, and naphthyl; and aralkyl groups such as benzyl, phenylethyl, and phenylpropyl.

[0058] In these monovalent hydrocarbon groups, some or all of the hydrogen atoms bonded to carbon can be replaced by other substituents. Examples include halogen-substituted hydrocarbon groups such as chloromethyl, bromoethyl, and trifluoropropyl, and cyano-substituted hydrocarbon groups such as cyanoethyl.

[0059] Among them, R 1 Preferably, it is an alkyl or phenyl group having 1 to 5 carbon atoms, and more preferably methyl, ethyl, or phenyl.

[0060] Alkylenes with 1 to 20 carbon atoms 2 It can be linear, branched, or cyclic. Examples include: methylene, ethylene, propylene, trimethylene, tetramethylene, isobutylene, pentamethylene, hexamethylene, cyclohexylene, heptamethylene, octamethylene, nonamethylene, and decylene.

[0061] Among them, R 2 Preferably, it is composed of oxygen atoms, methylene, ethylene, and trimethylene, and more preferably oxygen atoms or ethylene.

[0062] Additionally, for R 3 The number of carbon atoms in the alkyl (alkylene) group of acryloyloxyalkyl, methacryloyloxyalkyl, acryloyloxyalkoxy, or methacryloyloxyalkoxy is not particularly limited, but is preferably 1 to 10, more preferably 1 to 5. Specific examples of alkyl groups include the aforementioned R. 1 The example groups are alkyl groups with 1 to 10 carbon atoms.

[0063] Group R 3 Specific examples include, but are not limited to, examples with the following formula.

[0064]

[0065] Where b represents a number satisfying 1 ≤ b ≤ 4, and R 5 Indicates alkylene groups having 1 to 10 carbon atoms.

[0066] In the above example, p represents a number that satisfies 0 ≤ p ≤ 10, preferably 0 or 1. a represents a number that satisfies 1 ≤ a ≤ 3, preferably 1 or 2.

[0067] In the organopolysiloxane molecule of component (A), groups having the above general formula (1) may be attached to the ends of the molecular chain and / or non-ends of the molecular chain (i.e., located in the middle of the molecular chain or on the side chain of the molecular chain). From the perspective of flexibility, groups having formula (1) are preferably present only at the ends of the molecular chain.

[0068] In the organopolysiloxane molecule of component (A), examples of organic groups bonded to silicon other than those having the groups of the above general formula (1) include those with the R group described above. 1The same group as the group shown in the example is preferably a monovalent hydrocarbon group with 1 to 12 carbon atoms, and particularly preferably a monovalent hydrocarbon group with 1 to 10 carbon atoms other than an aliphatic unsaturated group.

[0069] Specific examples include those related to the above R. 1 The same groups used in the examples are preferably alkyl, aryl, and haloalkyl groups from the viewpoint of ease of synthesis, and more preferably methyl, phenyl, and trifluoropropyl groups.

[0070] Component (A) has the following molecular structure: a substantially linear or branched backbone (including a partially branched linear backbone) composed of repeating diorganosiloxane units. In particular, it is preferred to be a linear diorganopolysiloxane whose two ends of the molecular chain are capped with groups having the above general formula (1).

[0071] Component (A) may be a homopolymer having this molecular structure, a copolymer having this molecular structure, or a mixture of two or more polymers.

[0072] Specific examples of monofunctional (meth)acrylate compounds (B) without siloxane structures include: isoamyl acrylate, lauryl acrylate, stearyl acrylate, ethoxydiethylene glycol acrylate, methoxytriethylene glycol acrylate, 2-ethylhexyl-diethylene glycol acrylate, phenoxyethyl acrylate, phenoxydiethylene glycol acrylate, tetrahydrofurfuryl acrylate, and isobornyl acrylate. These compounds can be used alone or in combination of two or more.

[0073] The preferred ester isobornyl acrylate.

[0074] The monovalent hydrocarbon group R with 1 to 10 carbon atoms in component (C) 4 Specific examples include the above R 1 The groups in the examples are monovalent hydrocarbon groups having 1 to 10 carbon atoms. Preferably, they are alkyl groups having 1 to 5 carbon atoms, such as methyl, ethyl, n-propyl, and n-butyl; or aryl groups having 6 to 10 carbon atoms, such as phenyl and tolyl, and more preferably methyl, ethyl, and phenyl.

[0075] With R 1 Similarly, monovalent hydrocarbon group R 4 Some or all of the hydrogen atoms bonded to carbon can be replaced by the other substituents mentioned above.

[0076] Specific examples of photopolymerization initiators for component (D) include: 2,2-diethoxyacetophenone, 2,2-dimethoxy-1,2-diphenylethane-1-one (BASF Irgacure 651), 1-hydroxy-cyclohexyl-phenyl-one (BASF Irgacure 184), 2-hydroxy-2-methyl-1-phenyl-propane-1-one (BASF Irgacure 1173), 2-hydroxy-1-{4-[4-(2-hydroxy-2-methyl-propanoyl)-benzyl]-phenyl}-2-methyl-propane-1-one (BASF Irgacure 127), methyl benzoylformate (BASF Irgacure MBF), 2-methyl-1-[4-(methylthio)phenyl]-2-morpholinylpropane-1-one (BASF Irgacure 907), 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)-1-butanone (BASF Irgacure 369), bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide (BASF Irgacure 819), and 2,4,6-trimethylbenzoyl-diphenylphosphine oxide (BASF Irgacure TPO). These compounds can be used alone or in combination of two or more.

[0077] From the viewpoint of compatibility with component (A), 2,2-diethoxyacetophenone, 2-hydroxy-2-methyl-1-phenyl-propane-1-one (BASF Irgacure 1173), bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide (BASF Irgacure 819), and 2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide (BASF Irgacure TPO) are preferred.

[0078] In this invention, in addition to the UV-curable silicone pressure-sensitive adhesive compositions described above, thermosetting silicone pressure-sensitive adhesive compositions can also be used. Specific examples include the SIM series manufactured by Shin-Etsu Chemical Co., Ltd., and from the viewpoint of curing time, particularly SIM-360 and silicone rubber compositions such as the STP series.

[0079] There is no particular limitation on the thickness of the silicone pressure-sensitive adhesive layer. From the viewpoint of formability and flatness, it is preferably 1 to 100 μm, more preferably 10 to 30 μm, and even more preferably 15 to 25 μm.

[0080] The shape of the silicone pressure-sensitive adhesive layer can be flat or have raised surfaces such as concave and convex, depending on the component size and component spacing.

[0081] For example, in the case of a silicone pressure-sensitive adhesive layer with a convex structure, the size and arrangement of the convex structure can be designed according to the size and desired arrangement of the microstructures to be transferred. The upper surface of the convex structure is flat. There are no limitations on the shape of this surface, and examples include circles, ellipses, and quadrilaterals. In the case of a quadrilateral, the edges may be rounded. There are no particular limitations on the width of the upper surface of the convex structure, which is preferably 0.1 μm to 1 cm, more preferably 1 μm to 1 mm.

[0082] There are no restrictions on the form of the side surface of the convex structure; it can be vertical or oblique. The height of the convex structure is preferably 1 to 100 μm, more preferably 10 to 30 μm. The spacing between adjacent convex structures is preferably 0.1 μm to 10 cm, more preferably 1 μm to 1 mm.

[0083] There are no particular restrictions on the size of the silicone pressure-sensitive adhesive layer, as long as it is suitable for the front side of the synthetic quartz glass substrate, for example, it can be the same size as the synthetic quartz glass substrate.

[0084] As described above, the front side of the synthetic quartz glass substrate used in the substrate for transferring microstructures according to the present invention is etched. While CO2 lasers are typically used to etch text or QR codes on the front side of synthetic quartz glass substrates, the present invention can also apply etched markings (laser markings) using the same technique.

[0085] In QR codes, there are no particular restrictions on the depth and size (diameter) of each dot to be engraved. The dot depth is preferably 3 to 25 μm, more preferably 5 to 15 μm, and the dot size is preferably 20 to 200 μm, more preferably 30 to 180 μm.

[0086] In addition, there are no particular restrictions on the depth and size of the text. The depth of each character is preferably 3 to 25 μm, more preferably 5 to 15 μm, and the size of each character is preferably 1000 to 1600 μm.

[0087] Within this range, when the silicone pressure-sensitive adhesive layer is applied to the front side of the synthetic quartz glass substrate, the periphery of the etched markings is less likely to contain air bubbles, thus reducing the likelihood of problems when reading the etched markings.

[0088] The method for reading the engraving can be appropriately selected from well-known methods. Examples include devices for reading general dot matrices (so-called 2D barcode readers). Specific examples include the Keyence Corporation 2D barcode reader (SR-2000), but since QR codes have various standards, a reader suitable for each standard should be selected. Text can be read visually or using a reading device.

[0089] [2] Method for manufacturing a substrate for transferring microstructures

[0090] The synthetic quartz glass substrate used in this invention can be manufactured using common methods. Specifically, a silane compound is introduced into an oxyhydrogen flame, and a synthetic quartz ingot is obtained through a hydrolysis reaction. The obtained ingot is sliced, chamfered, double-sided lapped, double-sided polished, and cleaned to obtain the synthetic quartz glass substrate.

[0091] At this point, in order to set the flatness and thickness variation of the synthetic quartz glass substrate and the power spectral density of the front side to appropriate values ​​as described above, for example, after general lap grinding, a hard polishing pad with a hardness of 70 or higher (Shore A grade) is leveled with an appropriate diamond granule carrier, and then the surface of the substrate is polished with a hard polishing pad and a slurry of cerium oxide or colloidal silica.

[0092] Next, markings (such as text and QR codes) are engraved on the front side of the synthetic quartz glass substrate on which an organosilicon pressure-sensitive adhesive layer is applied.

[0093] As a method for implementing marking, a CO2 laser can be used, as described above. Specific examples of CO2 lasers include, but are not limited to, laser marking machines (ML-Z9600 / 9650) manufactured by Keyence Corporation.

[0094] In CO2 laser lithography, the main parameters that can be set are the number of scans, output intensity, and scanning speed. By adjusting these parameters, it is possible to obtain etched marks with the desired depth and size. For example, etching with a large output and a slow scanning speed results in deep etched marks, but raises (debris) are generated around the etched text or dots, causing dirt or contact scratches on the substrate. Adjusting the laser conditions can suppress these raises to some extent, but it is difficult to reliably planarize them. Raises can be removed by mechanical polishing, thus reliably planarizing them, but this increases the number of processes and leads to increased costs.

[0095] Next, an organosilicon pressure-sensitive adhesive layer is applied to the front side of the resulting synthetic quartz glass substrate with engraved markings.

[0096] Examples of methods for forming silicone pressure-sensitive adhesive layers include: a method of directly applying an uncured silicone pressure-sensitive adhesive composition to the front side of a substrate and curing the composition, and a method of attaching a sheet-like cured product formed from the silicone pressure-sensitive adhesive composition to the front side of a substrate.

[0097] As described above, the silicone pressure-sensitive adhesive composition can be a UV-curable silicone pressure-sensitive adhesive composition or a thermosetting silicone pressure-sensitive adhesive composition.

[0098] In a method of directly applying a silicone pressure-sensitive adhesive composition to the front side of a substrate and curing the composition, the substrate for transferring microstructures can be obtained by applying the silicone pressure-sensitive adhesive composition to the front side of the substrate and then irradiating it with ultraviolet light or heating it to cure the composition.

[0099] The coating method can be appropriately selected and used from well-known coating methods, such as spin coaters, corner roller coaters, lip coaters, roller coaters, die coaters, knife coaters, doctor blade coaters, bar coaters, kiss coaters, gravure coaters, screen coating, dip coating, and cast coating. Spin coaters are preferred.

[0100] When using a spin coater, the silicone pressure-sensitive adhesive composition can be coated by spin coating to a thickness of preferably 1-100 μm, more preferably 10-30 μm, and even more preferably 15-25 μm, and then placed in a heating oven for curing, preferably at 20-200°C for 5-90 minutes, or cured by irradiation with ultraviolet light, thereby obtaining a silicone pressure-sensitive adhesive layer.

[0101] The silicone pressure-sensitive adhesive composition can be applied to the front side of a synthetic quartz glass substrate with etched markings by any of the above coating methods, and then cured while being pressed or compressed to obtain a substrate with high flatness and good thickness variation for transferring microstructures.

[0102] In another method, a sheet-like cured product formed from a silicone pressure-sensitive adhesive composition is bonded to the front side of a synthetic quartz glass substrate having etched markings on its front side. The silicone pressure-sensitive adhesive composition is molded into a sheet shape, and then the sheet is bonded to the synthetic quartz glass substrate. This allows for the preparation of a substrate for transferring microstructures.

[0103] Examples of methods for molding silicone pressure-sensitive adhesive compositions into sheet shapes include roll forming, compression molding, transfer molding, and compression molding.

[0104] To prevent the adhesion of dust and other contaminants and to suppress oxygen inhibition during curing, it is preferable to mold the composition into a sheet-like cured product while it is sandwiched between plastic films. If the resulting sheet-like cured product is larger than the desired size, it can be cut to the desired size.

[0105] In addition, to improve the adhesion between the sheet-like cured product and the synthetic quartz glass substrate with engraved markings on the front side, either or both of the bonding surfaces can be subjected to plasma treatment, excimer laser treatment, or chemical treatment. To improve the bonding strength, adhesives or pressure-sensitive adhesives can be used. Specific examples of adhesives or pressure-sensitive adhesives include silicone-based, acrylic-based, and epoxy-based adhesives.

[0106] As a bonding method, roller bonding or vacuum pressing can be used.

[0107] The curing conditions for heat-curing or UV-curing silicone pressure-sensitive adhesive compositions can be appropriately set according to the silicone pressure-sensitive adhesive composition used.

[0108] The substrate for transferring microstructures obtained as described above can be used for transferring microstructures (e.g., micro LED display elements).

[0109] The transfer of microstructures using the substrate for transferring microstructures of the present invention can be performed, for example, by the following techniques.

[0110] That is, a plurality of microstructures formed on one surface of a supply substrate are bonded to an organosilicon pressure-sensitive adhesive layer disposed on a substrate for transferring microstructures according to the present invention. Part or all of the plurality of microstructures are separated from the supply substrate and transferred to a substrate for transferring microstructures having an organosilicon pressure-sensitive adhesive layer, thereby obtaining a transfer substrate with a plurality of microstructures temporarily fixed thereon.

[0111] The resulting temporary transfer substrate, which has multiple microstructures fixed thereon, is then bonded to another transfer substrate used in the next step, and the transfer is performed in the same manner as described above. To transfer components by bonding, techniques such as differences in adhesive strength between silicone resins, laser ablation, or laser peeling can be utilized.

[0112] Example

[0113] The present invention will now be described in more detail with reference to embodiments and comparative examples, but the present invention is not limited to these embodiments.

[0114] Example 1

[0115] A circular synthetic quartz glass substrate with an outer diameter of 150 mm and a thickness of 1.0 mm was manufactured. For any 6.01 mm × 6.01 mm area on the front and back sides of this synthetic quartz glass substrate, when measured using a white light interferometer (Nexview NX2, manufactured by Zygo Corporation, hereinafter the same) at a pixel count of 1240 × 1240, the spatial frequency of 1 mm was obtained. -1 The above power spectral density is 10 12nm 4 The surface roughness (Ra) of the front and back sides, measured using an atomic force microscope (NX20, manufactured by Park Systems, hereinafter the same), is 0.01 μm.

[0116] like Figure 1 As shown in Figures A and 1B, an etch mark 12 is applied to the front surface 11 of the synthetic quartz glass substrate 10 using a laser marking machine (ML-Z9600 / 9650, manufactured by Keyence Corporation, hereinafter the same). This etch mark 12 is a two-dimensional matrix code symbol defined in SEMI T7 0303, formed at a position 1 mm from the edge of the front surface 11 of the synthetic quartz glass substrate 10. The content of the dots in the etch mark 12 is "20010012A1D6". The laser conditions used to form the etch mark 12 are set as follows: output intensity 70%, scanning speed 100 mm / sec, number of scans 2, and unit size 0.115 mm.

[0117] The depth of the dot matrix of the etched mark 12 obtained under these conditions was measured using a stylus-type ripple gauge (Surfcom NEX041, manufactured by Tokyo Seimitsu Co., Ltd., hereinafter the same), and was 20 μm. When the dot size was measured using a microscope, the dots were found to be circular with a diameter of 100 μm.

[0118] The resulting synthetic quartz glass substrate 10 with engraved markings is ultrasonically cleaned with pure water and then dried.

[0119] In addition, the base compound (STP-204, manufactured by Shin-Etsu Chemical Co., Ltd.) and the curing agent (STP-204(CAT, manufactured by Shin-Etsu Chemical Co., Ltd.) of the liquid heat-curing silicone pressure-sensitive adhesive composition were mixed at a ratio of 100:10 (by mass), and then applied to the front side with the etched markings using a spin coater at 2500 rpm for 2 minutes. Then, it was heated on a hot plate at 150°C for 5 minutes for curing, and then heated in an oven at 150°C for 25 minutes to provide a silicone pressure-sensitive adhesive layer 20, thereby obtaining a substrate 1 for transferring microstructures.

[0120] When the dot matrix of the etched marks 12 is read from the back side (the side without the silicone pressure-sensitive adhesive layer 20) of the substrate 1 used for transferring the microstructures using a two-dimensional reader (SR-2000 2D reader, manufactured by Keyence Corporation, hereinafter the same), the dot matrix can be correctly read as "20010012A1D6". Similarly, when the dot matrix of the etched marks 12 is read from the silicone pressure-sensitive adhesive layer 20 on the front side of the substrate 1 used for transferring the microstructures, the dot matrix can be correctly read as "20010012A1D6".

[0121] Furthermore, when an LED element, obtained by epitaxial growth and isolation on a sapphire substrate, is attached to the resin side and transferred using laser lift-off, the element is reliably transferred (transferred). After 10,000 consecutive element transfers, when the dot matrix is ​​read in the same manner as described above, the dot matrix can be correctly read as "20010012A1D6". After a further 10,000 consecutive element transfers, when the dot matrix is ​​read in the same manner as described above, the dot matrix can be correctly read as "20010012A1D6".

[0122] Comparative Example 1

[0123] A circular synthetic quartz glass substrate with an outer diameter of 150 mm and a thickness of 1.0 mm was fabricated. For any 6.01 mm × 6.01 mm area on the front and back sides of this synthetic quartz glass substrate, when measured using a white light interferometer at a pixel count of 1240 × 1240, the spatial frequency obtained was 1 mm. -1 The above power spectral density is 10 12 nm 4 The surface roughness (Ra) of the front and back sides, measured using atomic force microscopy, is 0.01 μm.

[0124] The back of the synthetic quartz glass substrate was laser-marked using a laser marking machine. The marking marks were two-dimensional matrix codes defined in SEMI T70303, and were marked 1 mm from the edge of the front side of the synthetic quartz glass substrate. The marking points were labeled "20010012A1D6". The laser conditions used for marking were set to 70% output intensity, 100 mm / sec scanning speed, 2 scans, and a unit size of 0.115 mm.

[0125] The depth of the lattice obtained under these conditions was measured to be 20 μm using a stylus-type ripple gauge. When the dot size was measured using a microscope, the dots were found to be circular with a diameter of 100 μm.

[0126] The resulting synthetic quartz glass substrate with engraved markings was ultrasonically cleaned with pure water and then dried.

[0127] Additionally, a heat-curing silicone pressure-sensitive adhesive composition (base compound / curing agent = 100 / 10), identical to that in Example 1, was applied to the front side with the etched markings using a spin coater at 2500 rpm for 2 minutes. Then, it was heated on a hot plate at 150°C for 5 minutes for curing, and subsequently heated in an oven at 150°C for 25 minutes to form the silicone pressure-sensitive adhesive layer, thereby obtaining a substrate for transferring microstructures.

[0128] When reading the dot matrix of etched marks from the back side (the side without the silicone pressure-sensitive adhesive layer) of the substrate used for transferring microstructures using a 2D reader, the dot matrix can be correctly read as "20010012A1D6". Similarly, when reading the dot matrix of etched marks from the silicone pressure-sensitive adhesive layer on the front side of the substrate used for transferring microstructures, the dot matrix can be correctly read as "20010012A1D6".

[0129] Furthermore, when LED components, epitaxially grown and insulated on a sapphire substrate, are attached to the resin side and transferred using laser lift-off, the components are reliably transferred. However, after 10,000 consecutive component transfers, when reading the dot matrix in the same manner as described above, the code "20010012A1D6" could not be correctly read from the silicone pressure-sensitive adhesive layer on the front side of the substrate, nor could it be correctly read from the back side of the substrate. It is speculated that during the component transfer process using the substrate, dirt and scratches caused by debris adhering to the markings on the back side prevent the markings from being read.

[0130] Japanese Patent Application No. 2020-085108 is incorporated herein by reference.

[0131] Although some preferred embodiments have been described, many modifications and variations can be made thereto in accordance with the foregoing teachings. Therefore, it should be understood that the invention can be practiced in ways other than those specifically described without departing from the scope of the appended claims.

Claims

1. A substrate for transferring microstructures, comprising: Synthetic quartz glass substrate, and An organosilicon pressure-sensitive adhesive layer disposed on the front side of the synthetic quartz glass substrate. The synthetic quartz glass substrate has etched markings on its front side, and the silicone pressure-sensitive adhesive layer is disposed to cover the etched markings.

2. The substrate for transferring microstructures according to claim 1, wherein, The synthetic quartz glass substrate has a spatial frequency of 1mm. -1 The above power spectral density is 10 12 nm 4 The power spectral density was obtained by measuring a 6.01 mm × 6.01 mm area on the front and back sides of the synthetic quartz glass substrate using a white light interferometer with a pixel count of 1240 × 1240.

3. The substrate for transferring microstructures according to claim 1, wherein, The surface roughness (Ra) of the back side of the synthetic quartz glass substrate is less than 0.05 μm.

4. The substrate for transferring microstructures according to claim 2, wherein, The surface roughness (Ra) of the back side of the synthetic quartz glass substrate is less than 0.05 μm.

5. The substrate for transferring microstructures according to any one of claims 1 to 4, wherein, The imprinted mark is a laser mark with a depth of 3~25μm and a dot size of 20~200μm.

6. A method for manufacturing a substrate for transferring microstructures, comprising the steps described in any one of claims 1 to 5: The process of setting engraving marks on the front side of a synthetic quartz glass substrate to obtain a synthetic quartz glass substrate with engraving marks, and The process of applying an organosilicon pressure-sensitive adhesive layer to the front side of the synthetic quartz glass substrate with etched markings.

7. The method for manufacturing a substrate for transferring microstructures according to claim 6, wherein, The process of setting the silicone pressure-sensitive adhesive layer is as follows: applying the silicone pressure-sensitive adhesive composition to the front side of a synthetic quartz glass substrate with etched markings, and then allowing it to cure.

8. The method for manufacturing a substrate for transferring microstructures according to claim 6, wherein, The process of setting the silicone pressure-sensitive adhesive layer is as follows: a cured product formed by the silicone pressure-sensitive adhesive composition is bonded to the front side of a synthetic quartz glass substrate with etched markings.

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