Adhesive film

Abstract

This invention relates to an adhesive film comprising an adhesive layer; a photothermal conversion layer containing a light absorber and a thermally decomposable resin; and an adhesive base film layer disposed between the adhesive layer and the photothermal conversion layer, wherein the adhesive base film layer contains a multifunctional epoxy resin, an adhesive resin, a curing agent, and a curing catalyst. The adhesive film according to this invention simplifies the substrate processing procedure and prevents damage to the substrate and circuits or components formed on the substrate.

Description

Prior Technology

[0001] This invention relates to an adhesive film, and more particularly, to an adhesive film disposed between a substrate to be processed and a support member during a substrate processing procedure.

[0002] In various fields, it is generally preferred to use thin or flexible substrates. A process has been proposed in which the substrate is bonded to a rigid support during the formation of such a thin or flexible substrate, and then separated from the rigid support after the substrate processing is completed.

[0003] As an example, in the field of quartz devices, it is preferable to reduce the thickness of the quartz wafer, thereby increasing the oscillation frequency. In particular, in the semiconductor industry, efforts are being made to further reduce the thickness of semiconductor wafers through wafer lamination technology and reductions in the thickness of semiconductor packaging, for use in high-density manufacturing.

[0004] Thickness reduction is achieved by grinding the so-called back surface of a semiconductor wafer on the surface opposite to the surface of the patterned circuit. To reduce thickness, a method has been proposed in which the bottom surface of the wafer is ground and transported while it is securely held to a rigid support with an adhesive, and then the wafer is separated from the rigid support. By using a rigid support to support the wafer, it is possible to prevent wafer breakage during back surface grinding and transport, and to process the wafer to a thin thickness level.

[0005] On the other hand, as another example, a flexible display device has been developed that enhances aesthetics and provides versatility in use, preferably using a flexible substrate. Flexible display devices are anticipated as the next generation of display devices, replacing portable computers, electronic newspapers or smart cards, and printed media such as books, newspapers, magazines, and the like. With the enhancement of aesthetics, reduction in thickness, and reduction in weight of this display device, various materials are required, and various flexible substrates are applied and used. For example, thin-film metal sheets, plastics, and the like can be used as flexible substrates.

[0006] However, due to the excellent bending properties of flexible substrates, they are rarely used in existing manufacturing equipment for display devices designed for glass or quartz substrates. For example, there are limitations in transporting or storing them in cassettes using track equipment or robots.

[0007] Therefore, before the element is formed, the flexible substrate is bonded to the rigid support; when the element is formed on the flexible substrate, the support supports the flexible substrate; and after the element is formed on the substrate, the support is detached from the flexible substrate. Thus, even using a flexible substrate, a flexible display device in which elements are stably formed can be provided.

[0008] However, the problem with this procedure is its complexity, which increases cost and time through processes such as applying and curing adhesives between the substrate and the rigid support. Furthermore, during the process of separating the substrate from the rigid support after substrate processing, there is a risk of damage to the wafer or the substrate itself, or damage to the wafer's circuitry and the components of the flexible substrate. Summary of the Invention

[0009] One object of the present invention is to provide an adhesive film that maintains high adhesion during the processing procedure and allows for easy detachment from the support member after the processing procedure. Therefore, in the present invention, damage and breakage of the substrate or components or circuits formed on the substrate due to physical forces can be prevented when the substrate separates from the support member.

[0010] Another object of the present invention is to provide an adhesive film that, due to its excellent heat resistance and excellent light-blocking properties, can prevent damage to the substrate to be processed and the components or circuits formed on the substrate, particularly for use even in processes requiring high vacuum / 250°C or higher heat resistance. More specifically, the present invention can be applied to processes requiring very rapid ramp-up, or to processes that exclude ramp-up processes themselves and expose the material to high temperatures in one step so that the thermal shock applied to the material is significant.

[0011] Another object of the present invention is to provide an adhesive film that can simplify the fixing of the substrate to be processed onto the support and reduce costs and time by peeling the substrate off from the support.

[0012] To address the problems of the prior art, the adhesive film of the present invention comprises an adhesive layer; a photothermal conversion layer containing a light absorber and a thermally decomposable resin; and an adhesive base film layer disposed between the adhesive layer and the photothermal conversion layer, wherein the adhesive base film layer contains a multifunctional epoxy resin, an adhesive resin, a curing agent, and a curing catalyst.

[0013] The adhesive layer may be based on a silicone adhesive layer.

[0014] Thermodegradable resins may contain two types of acrylic resins with -COOH or -OH functional groups and different weight average molecular weights.

[0015] The adhesive base film layer can adhere to both the adhesive layer and the photothermal conversion layer.

[0016] The curing agent may be a phenol-based curing agent.

[0017] The adhesive resin may be an elastomer resin having a weight average molecular weight of 500,000 to 1,500,000.

[0018] Adhesive resins can be acrylic-based or rubber-based elastomer resins.

[0019] Adhesive resins may have epoxy groups in their chains.

[0020] The adhesive base film layer may further contain fillers.

[0021] The filler may include at least one of the group consisting of TiO2, silica, copper powder, alumina and carbon black.

[0022] The weight ratio of adhesive resin to epoxy resin in the adhesive base film layer can be 25:75 to 55:45.

[0023] The adhesive film according to the present invention can maintain high adhesion during the processing procedure and easily peel off the substrate fixed to the support after the processing procedure. Therefore, when separating the substrate from the support, damage and breakage of the substrate and the components or circuits formed on the substrate by physical forces can be prevented. Furthermore, the adhesive film according to the present invention has excellent heat resistance and excellent light-blocking effect, and in particular, it can even be used in processes requiring high vacuum / 250°C or higher heat resistance. Moreover, the adhesive film according to the present invention can reduce costs and time by simplifying the fixing of the substrate to be processed to the support and the peeling of the substrate from the support. Simple Explanation of the Diagram

[0024]

[0025] 110: First pad

[0026] 120: Photothermal conversion layer

[0027] 130: Adhesive base film layer

[0028] 140: Adhesive layer

[0029] 150: Second pad

[0030] 200: Support component

[0031] 300: Substrate

[0032] 400: Laser

[0033] 500: Remove tape

[0034] [Figure 1] is a cross-sectional view of the adhesive film according to the present invention.

[0035] Figures 2A to 2C are diagrams illustrating the process of processing a substrate using an adhesive film according to the present invention. Implementation

[0036] The advantages and features of the present invention, as well as the methods for achieving them, will become more apparent from the detailed embodiments described below with reference to the accompanying drawings. However, the invention is not limited to the embodiments described below and may be implemented in many different forms. The embodiments are provided only to carry out the invention disclosed herein and fully provide the category of the invention to those skilled in the art to which it pertains, and the invention will be defined precisely as within the scope of the appended claims.

[0037] The shapes, dimensions, ratios, angles, numbers, and the like depicted in the drawings used to describe embodiments of the present invention are illustrative, and therefore the present invention is not limited to the details shown in the drawings. Throughout this specification, similar element symbols refer to similar components. Furthermore, in describing the present invention, detailed explanations of known related technologies will be omitted where it is determined that such detailed explanations would unnecessarily obscure the subject matter of the present invention.

[0038] When the terms "comprising" or "having" are used in this specification, other matters besides the details described may be added unless the expression "only" is used. When a component is referred to in the singular form, the component includes the plural form unless otherwise expressly stated.

[0039] Unless otherwise explicitly stated, components should be interpreted as including error scope.

[0040] In describing positional relationships, when terms such as "on," "above," "below," and "next" are used to describe the positional relationship between two components, one or more other components may also be located between the two components, unless the expressions "immediately" or "directly" are used.

[0041] Individual features of embodiments of the present invention may be partially or completely coupled or combined with each other, and may be technically interlocked or driven in various ways.

[0042] In the following description, embodiments of the invention will be detailed with reference to the accompanying drawings. The following embodiments are provided as examples so that the spirit of the invention will be fully conveyed to those skilled in the art. Therefore, the invention is not limited to the embodiments described below and can be embodied in various different configurations.

[0043] Figure 1 is a cross-sectional view of an adhesive film according to an embodiment of the present invention. Referring to Figure 1, the adhesive film according to an embodiment of the present invention includes a first pad 110, a photothermal conversion layer 120, an adhesive base film layer 130, an adhesive layer 140, and a second pad 150 laminated sequentially.

[0044] The adhesive film of the present invention is in the form of a film, and is formed by directly bonding the photothermal conversion layer 120 and the adhesive layer 140 to the two surfaces of the adhesive base film layer 130, which is formed in the form of a film. That is, in the adhesive film of the present invention, the adhesive base film layer 130 serves as a support film and is formed in a structure having multiple layers but not a rigid base film such as a PI film or a PEN film. In a subsequent substrate processing procedure, the adhesive layer 140 is bonded to the substrate, and the photothermal conversion layer 120 is bonded to the rigid support.

[0045] More specifically, when irradiated with radiant energy (such as laser), the photothermal conversion layer 120 is segmented and can be separated from the support without damaging the substrate or the components or circuits on the substrate.

[0046] The photothermal conversion layer 120 comprises a light absorber and a thermally decomposable resin. Radiant energy applied to the photothermal conversion layer 120 in the form of a laser or similar source is absorbed by the light absorber and converted into heat energy. The resulting heat energy causes the temperature of the photothermal conversion layer 120 to rise rapidly, reaching the thermal decomposition temperature of the thermally decomposable resin (organic component) in the photothermal conversion layer 120, thereby causing the resin to decompose. The gases produced by thermal decomposition form a porous layer (such as spaces) in the photothermal conversion layer 120, dividing the photothermal conversion layer 120 into two parts, resulting in the separation of the support and the substrate.

[0047] Light absorbers can absorb radiant energy and convert it into heat energy. Furthermore, light absorbers can act as light shields to prevent damage to the substrate from lasers or similar sources.

[0048] Although the light absorber varies depending on the wavelength of the laser, examples of usable light absorbers include carbon black, graphite powder, particulate metal powders (such as iron, aluminum, copper, nickel, cobalt, manganese, chromium, zinc, and tellurium), metal oxide powders (such as black titanium dioxide), and dyes and pigments (such as aromatic diamine-based metal complexes, aliphatic diamine-based metal complexes, aromatic dithiol-based metal complexes, mercaptophenol-based metal complexes, compounds based on squaric acid cyanine, anthocyanin-based dyes, methylene-based dyes, naphthoquinone-based dyes, and anthraquinone-based dyes). The light absorber may also be in the form of a film, including a vapor-deposited metal film.

[0049] Among these light absorbers, carbon black is particularly useful because, after irradiation, carbon black significantly reduces the force required for the self-supporting element to separate from the substrate and accelerates the separation.

[0050] The particle size of the light absorber in the photothermal conversion layer 120 can be from about 20 nm to about 2000 nm, preferably from about 50 nm to about 1000 nm, and even more preferably from about 100 nm to about 350 nm.

[0051] When the particle size of the light absorber is less than approximately 20 nm, dispersion becomes difficult. Furthermore, smaller particle sizes result in higher surface areas, preventing the loading of large quantities of light absorber and limiting the loading amount. Additionally, when the particle size of the light absorber exceeds approximately 2000 nm, laser blocking performance decreases, and the laser's ability to segment the photothermal conversion layer 120 is also reduced. Moreover, as the particle size of the light absorber increases, film formation decreases, dispersion stability decreases after dispersion, and the time required until the crude liquid is formed and coated should be shortened.

[0052] Based on the total weight of the photothermal conversion layer 120, the content of the light absorber in the photothermal conversion layer 120 can be from about 5 wt% to about 80 wt%, more preferably from about 10 wt% to about 60 wt%, and even more preferably from about 20 wt% to about 50 wt%.

[0053] When the content of the light absorber is less than about 5 wt%, separation by laser is difficult. Furthermore, when the content of the light absorber is more than about 80 wt%, after laser separation of the photothermal conversion layer 120, a portion of the laser-separated photothermal conversion layer 120 remains on the surface of the adhesive base film layer 130, and at this point, due to the high carbon content, the adhesion becomes very low. In this case, during the subsequent process of removing the adhesive base film layer 130 and the adhesive layer 140 with removal tape, the adhesive base film layer 130 does not bond well with the removal tape and is therefore difficult to remove. Moreover, as the content of the light absorber increases, the adhesion of the surface of the photothermal conversion layer 120 becomes too low, resulting in difficulty in laminating with the support and uneven dispersion of the light absorber.

[0054] The thermally decomposable resin in the photothermal conversion layer 120 includes an acrylic resin. Preferably, the acrylic resin includes monomers selected from the group consisting of methyl methacrylate (MMA), hydroxyethyl methacrylate (HEMA), ethyl acrylate (EA), butyl acrylate (BA), acrylonitrile (AN), and combinations thereof. More preferably, the acrylic resin is selected from at least three of methyl methacrylate (MMA), hydroxyethyl methacrylate (HEMA), ethyl acrylate (EA), butyl acrylate (BA), and acrylonitrile (AN). The acrylic resin may have suitable molecular weight, Tg, heat resistance, and functional groups.

[0055] Based on the total weight of the photothermal conversion layer 120, the content of acrylic resin can be from about 5 wt% to about 80 wt%, preferably from about 15 wt% to about 60 wt%, and even more preferably from about 40 wt% to about 60 wt%. When the content of acrylic resin is less than about 5 wt%, the film-forming properties decrease, making it difficult to control the thickness of the photothermal conversion layer 120, and the surface adhesion of the photothermal conversion layer 120 is too low, making it difficult to laminate with the support. Furthermore, when the content of acrylic resin is greater than about 80 wt%, after laser irradiation, physical force is largely required to separate the photothermal conversion layer 120 from the support, making it difficult to separate the substrate, and potentially causing damage to the substrate or the components or circuits formed on the substrate.

[0056] The acrylic resin preferably comprises two acrylic resins with different weight average molecular weights, more preferably a high molecular weight acrylic resin and a low molecular weight acrylic resin. The high molecular weight acrylic resin allows the photothermal conversion layer 120 to have excellent heat resistance, while the low molecular weight acrylic resin improves the adhesion of the photothermal conversion layer 120 and is beneficial to film formation.

[0057] At this point, the Tg (glass transition temperature) of the high molecular weight acrylic resin is 0°C to 10°C, while the Tg of the low molecular weight acrylic resin can be -10°C to 0°C. When the Tg of the high molecular weight acrylic resin is higher than 10°C and the Tg of the low molecular weight acrylic resin is higher than 0°C, the heat resistance of the photothermal conversion layer 120 can be improved, but the surface adhesion may be reduced. On the other hand, when the Tg of the high molecular weight acrylic resin is lower than 0°C and the Tg of the low molecular weight acrylic resin is lower than -10°C, the bonding performance can be improved, but the heat resistance may be reduced.

[0058] The weight average molecular weight of the high molecular weight acrylic resin can be from about 400,000 g / mol to about 15,000,000 g / mol, more preferably from about 500,000 g / mol to about 1,200,000 g / mol, and even more preferably from about 700,000 g / mol to about 1,000,000 g / mol. When the weight average molecular weight of the high molecular weight acrylic resin is less than about 400,000 g / mol, the heat resistance of the photothermal conversion layer 120 decreases, and when its weight average molecular weight is greater than about 15,000,000 g / mol, the coating of the photothermal conversion layer 120 is not easy to mix with the crude solution.

[0059] The weight average molecular weight of the low molecular weight acrylic resin can be from about 50,000 g / mol to about 600,000 g / mol, more preferably from about 100,000 g / mol to about 500,000 g / mol, and even more preferably from about 400,000 g / mol to about 500,000 g / mol. When the weight average molecular weight of the low molecular weight acrylic resin is less than about 50,000 g / mol, the heat resistance of the photothermal conversion layer 120 decreases, and when its weight average molecular weight is greater than about 600,000 g / mol, the lamination performance of the photothermal conversion layer 120 deteriorates.

[0060] The weight ratio of high molecular weight acrylic resin to low molecular weight acrylic resin can be from about 1:4 to about 4:1, preferably from about 1:3 to about 3:1, and more preferably from about 1:2 to about 2:1. When the content of low molecular weight acrylic resin is significantly less than the content of high molecular weight acrylic resin, the lamination performance of the photothermal conversion layer 120 deteriorates. Furthermore, when the content of high molecular weight acrylic resin is significantly less than the content of low molecular weight acrylic resin, the heat resistance of the photothermal conversion layer 120 decreases, and after laser irradiation, the adhesion on the split surface of the photothermal conversion layer 120 is strong, thus requiring a large physical force to separate it.

[0061] The thermodegradable resin has -COOH or -OH functional groups. Preferably, the thermodegradable resin includes an acrylic resin having -COOH or -OH functional groups. The photothermal conversion layer 120, comprising a thermodegradable resin having -COOH or -OH functional groups, is not a pressure-sensitive adhesive type. By having -COOH or -OH functional groups, the photothermal conversion layer can be bonded to a support via hydrogen bonding, and for example, to silanol groups on the glass surface of a glass support via hydrogen bonding. In this case, hydrogen bonding provides initial adhesion for bonding the adhesive layer to the support, and the adhesion between the photothermal conversion layer 120 and the support is greatly increased due to the heat generated in subsequent processes after bonding.

[0062] The -COOH or -OH functional groups may have an acid value of at least about 1 mg KOH / g, preferably at least about 5 mg KOH / g. The lamination performance of the photothermal conversion layer 120 is based on the -COOH or -OH functional groups. When the acid value of the -COOH or -OH functional groups is below about 1 mg KOH / g, the lamination performance deteriorates. The upper limit of the acid value of -COOH or -OH is not a problem. However, due to the chemical structure, the -COOH or -OH functional groups may have an acid value of preferably about 1 mg KOH / g to about 50 mg KOH / g, more preferably about 1 mg KOH / g to about 30 mg KOH / g, and most preferably about 10 mg KOH / g to about 20 mg KOH / g.

[0063] The photothermal conversion layer 120 may further include inorganic fillers. Due to the formation of a porous layer caused by the thermal decomposition of the thermally decomposable resin, the inorganic fillers act to prevent re-adhesion of the photothermal conversion layer after the photothermal conversion layer 120 is segmented. Therefore, after processing the substrate, when the photothermal conversion layer 120 is irradiated with a laser and then separated, the physical force required to separate the substrate from the support can be further reduced.

[0064] The inorganic filler can be selected from SiO2, Al2O3, TiO2, and combinations thereof. Specifically, in the case of TiO2, it provides additional light-shielding effect to the substrate.

[0065] The particle size of the inorganic filler in the photothermal conversion layer 120 can be from about 20 nm to about 2000 nm, preferably from about 50 nm to about 1000 nm, and more preferably from about 100 nm to about 350 nm. When the particle size of the inorganic filler is less than about 20 nm, the inorganic filler is not easy to disperse during membrane production, and there is a limitation on the amount that can be loaded. In addition, when the particle size of the inorganic filler is greater than about 2000 nm, the membrane formation performance decreases, and the dispersion persistence after dispersion decreases.

[0066] Based on the total weight of the photothermal conversion layer 120, the content of inorganic filler in the photothermal conversion layer 120 can be from about 4 wt% to about 60 wt%, preferably from about 5 wt% to about 50 wt%, and even more preferably from about 5 wt% to about 30 wt%. When the content of inorganic filler is less than about 4 wt%, the adhesion of the separated surface is high after the separation process by laser irradiation, so the photothermal conversion layer 120 can be re-bonded over time. In addition, when the content of inorganic filler is greater than about 60 wt%, the adhesion of the photothermal conversion layer 120 is too low, making it difficult to laminate the photothermal conversion layer on the support, reducing film formation, and causing uneven dispersion.

[0067] The photothermal conversion layer 120 may further include a dispersant. Based on the total weight of the photothermal conversion layer 120, the content of the dispersant may be from about 0.1 wt% to about 10 wt%, more preferably from about 0.1 wt% to about 7 wt%, and even more preferably from about 0.1 wt% to about 5 wt%. When the content of the dispersant is less than about 0.1 wt%, the dispersibility of the light absorber and inorganic filler in the photothermal conversion layer 120 may decrease, and the dispersion persistence after dispersion may also decrease. Furthermore, when the content of the dispersant is greater than about 10 wt%, the heat resistance of the photothermal conversion layer 120 deteriorates, the additives to be added decompose at high temperatures, and weight loss increases.

[0068] The thickness of the photothermal conversion layer 120 is approximately 1 μm to approximately 30 μm, preferably approximately 3 μm to approximately 20 μm, and more preferably approximately 5 μm to approximately 15 μm. When the thickness of the photothermal conversion layer 120 is less than approximately 1 μm, the upper adhesive layer can directly affect the material, and the laser blocking performance can be degraded due to the light absorber. Furthermore, when the thickness of the photothermal conversion layer 120 is greater than approximately 30 μm, a large amount of adhesive residue can remain on the support after laser irradiation.

[0069] The photothermal conversion layer 120 is formed in the form of a film on the adhesive base film layer 130. When the photothermal conversion layer 120 is applied directly to the support and formed in liquid form, if the viscosity is low, its thickness is less than about 1 μm, which may result in insufficient thickness. For this reason, it is difficult to fully utilize light absorbers that can block lasers and it is difficult to prevent laser damage to the substrate.

[0070] In this invention, the photothermal conversion layer 120 can be directly applied to the support and formed in liquid form. After being formed into a film by separate application, the photothermal conversion layer 120 can be bonded to the adhesive base film layer 130 by a thermal lamination process.

[0071] When the photothermal conversion layer 120 according to the invention is formed in the form of a film, its thickness is easily controlled, and it may be more advantageous in protecting the substrate and the circuits or components formed thereon. Furthermore, this photothermal conversion layer 120 can have an adhesion to the support of 150 gf / 25 mm to 1600 gf / 25 mm.

[0072] Meanwhile, the adhesive layer 140 is used to fix the substrate. After separating the substrate and the support by decomposing the photothermal conversion layer 120, a substrate with the adhesive layer 140 thereon is obtained. Therefore, the adhesive layer 140 should be easily separated from the substrate by peeling or similar means. The adhesive layer 140 is in the form of a film formed on the adhesive base film layer 130 and is not a photocurable adhesive directly applied to the substrate.

[0073] The adhesive layer 140 may be a silicone-based adhesive layer. Preferably, the adhesive of the polysiloxane-based adhesive layer may include a free radical curable polysiloxane-based adhesive.

[0074] In substrate processing (especially semiconductor manufacturing), adhesive films with excellent stability under high temperature and high vacuum conditions are required. However, in the case of acrylic adhesive layers, for example, the temperature limit for heat resistance is 230°C, and if the process is performed at higher temperatures or for extended periods, the adhesive can melt and flow. Furthermore, because acrylic adhesives and the like have high CTE but low modulus and are flexible, they can move due to material deformation at high temperatures. Therefore, acrylic adhesives suffer from insufficient heat resistance, making them unusable in high-temperature / high-vacuum processes, and also exhibit poor adhesion under conditions such as high temperatures and similar conditions.

[0075] On the other hand, polysiloxane-based adhesive layers exhibit excellent stability and heat resistance at high temperatures. Furthermore, since polysiloxane-based adhesive layers are softer than adhesive layers made of other materials (such as acrylic adhesive layers), they offer superior lamination performance when bonding hard materials (such as substrates and supports).

[0076] Furthermore, the soft nature of the silicone adhesive layer allows the adhesive layer 140 to be gently removed after the substrate processing is completed, preventing damage to components on the substrate. Additionally, high temperatures can be used when peeling off the adhesive layer 140 after the substrate processing is complete, ensuring no residue remains on the substrate.

[0077] The adhesive layer 140 may include a curing agent. Preferably, the curing agent may be a benzoyl peroxide (BOP) curing agent. More preferably, the benzoyl peroxide (BOP) curing agent may be bis-(2,4-dichlorobenzoyl)peroxide or dibenzoyl peroxide. For example, the benzoyl peroxide (BPO) curing agent may be used in powder or paste form.

[0078] Based on the total weight of the adhesive layer 140, the content of the curing agent in the adhesive layer 140 may be from about 1 wt% to about 4 wt%, more preferably from about 1 wt% to about 3 wt%, and even more preferably from about 2 wt% to about 3 wt%.

[0079] When the content of the curing agent is less than about 1 wt%, the reactivity may deteriorate. In addition, when the content of the curing agent is greater than about 4 wt%, the excess curing agent may not react and unreacted curing agent may remain, and the transparency and roughness of the surface of the adhesive layer 140 may decrease after curing and drying.

[0080] The adhesive layer 140 may further include additives. The additives are used to remove moisture in the polysiloxane-based adhesive layer 140. That is, the additives remove moisture in the adhesive layer 140 to improve the curing efficiency of the adhesive layer 140, thereby further improving the heat resistance of the adhesive layer 140.

[0081] Preferably, the additive can be TiO2. For example, in the case of Al2O3, SiO2, or similar materials, the dispersibility is weak, and therefore a dispersant is required. However, in the case of a polysiloxane-based adhesive layer, because an aromatic solvent is used as the solvent, it is difficult to use it as the main dispersant, and when such a dispersant is added, the heat resistance of the polysiloxane may be deteriorated due to the dispersant.

[0082] In the case of TiO2, the dispersibility is excellent, and TiO2 is a filler that can be applied without special dispersants. Furthermore, the ability to remove moisture and the like can prevent moisture from reducing the curing reaction during the free radical reaction of silicon.

[0083] The size of the additive in the adhesive layer 140 is about 100 nm to about 500 nm, preferably about 200 nm to about 400 nm, and even more preferably about 200 nm to about 300 nm.

[0084] When the size of the additive is less than about 100 nm, the dispersibility decreases and the amount that can be loaded is limited. In addition, when the size of the additive is greater than about 500 nm, the following problems may occur: the additive may settle over time after dispersion and the surface roughness may be poor when coated with resin.

[0085] Based on the total weight of the adhesive layer 140, the content of additives in the adhesive layer 140 may be from about 1 wt% to about 10 wt%, more preferably from about 1 wt% to about 8 wt%, and even more preferably from about 1 wt% to about 5 wt%.

[0086] When the additive content is less than about 1 wt%, the additive's effectiveness is difficult to demonstrate. Furthermore, when the additive content is greater than about 10 wt%, problems may occur on the surface of the adhesive layer 140. The thickness of the adhesive layer 140 is about 5 μm to about 100 μm, preferably about 5 μm to about 70 μm, and more preferably about 10 μm to about 60 μm. When the thickness of the adhesive layer 140 is less than about 5 μm, interlayer delamination may occur when the device deforms severely due to low adhesion. Furthermore, when the thickness of the adhesive layer 140 is greater than about 100 μm, the drying efficiency during the formation of the adhesive layer 140 decreases, solvent residue may remain, and the cohesion within the adhesive layer 140 decreases, thus residues may remain. Due to the flexible nature of the adhesive layer 140, it may be difficult to fix the adhesive layer 140 during substrate processing.

[0087] On the other hand, when the adhesive layer 140 is based on a polysiloxane adhesive layer, and the photothermal conversion layer 120 includes an acrylic component, it is difficult to directly coat the photothermal conversion layer 120 between the polysiloxane-based material and the acrylic material. Specifically, due to the low surface energy of the silicon-based adhesive, the photothermal conversion layer 120 may not be coated on the silicon-based adhesive layer 140. Conversely, due to the high curing temperature of the polysiloxane-based adhesive, the adhesiveness of the photothermal conversion layer 120 is reduced, and the adhesive layer 140 may not be coated on the photothermal conversion layer 120.

[0088] In addition, a support film layer is needed to support the photothermal conversion layer 120 and the adhesive layer 140.

[0089] To support the photothermal conversion layer 120 and the adhesive layer 140, solid films, such as PI films or similar materials, have been designed. However, PI films, while possessing high stiffness and modulus, typically exhibit a larger CTE than the support or substrate (such as a wafer). Consequently, wrinkling, distortion, warping, and similar issues may occur with PI films at high temperatures. Due to wrinkling, distortion, and warping of the PI film, irregular surfaces may affect substrate processing and may lead to process defects.

[0090] Furthermore, when using rigid base films (such as PI films), there is the issue of needing to treat the polysiloxane primer on the PI film. This results in increased procedures, costs, and time.

[0091] In addition, an additional adhesive layer is required to bond the PI film to the photothermal conversion layer 120, resulting in an increase in the overall thickness of the film and a more complex structure.

[0092] To address these issues, in this invention, an adhesive base film layer 130 is formed between the photothermal conversion layer 120 and the adhesive layer 140 to support and bond the photothermal conversion layer 120 and the adhesive layer 140. That is, the adhesive base film layer 130 of this invention can reduce or prevent problems caused by rigid base films. Specifically, due to its lower modulus compared to PI films, the adhesive base film layer 130 expands or contracts according to the thermal behavior of the material or support, thus preventing problems such as wrinkling, distortion, warping, and the like.

[0093] Furthermore, when the adhesive base film layer 130 is used instead of the rigid film, the photothermal conversion layer 120, the adhesive base film layer 130, and the adhesive layer 140 are all flexible layers made of adhesive material to configure the adhesive film. As a result, the adhesive film itself exhibits flexibility, which is more advantageous when laminated to the support and the substrate, and exhibits high adhesion.

[0094] The adhesive base film layer 130 includes an epoxy resin. Preferably, the adhesive base film layer 130 includes a multifunctional epoxy resin. More preferably, the multifunctional epoxy resin may be a phenolic epoxy resin or a dicyclopentadiene epoxy resin. The multifunctional epoxy resin can increase chemical resistance by implementing a high crosslinking density.

[0095] The adhesive base film layer 130 is chemically resistant to solvents used in the photothermal conversion layer 120, such as methyl ethyl ketone (MEK) and ethyl acrylate (EA), and solvents used in the adhesive layer 140, such as toluene and xylene.

[0096] Furthermore, even at high temperatures, the adhesive base film layer may not expand or contract between the photothermal conversion layer 120 and the adhesive layer 140. In particular, even at the curing temperature of the polysiloxane-based adhesive layer 140, it maintains physical rigidity without shrinkage or expansion.

[0097] Furthermore, the adhesive base film layer 130 has a CTE and modulus suitable for the process and does not exhibit physical changes in subsequent substrate processing procedures.

[0098] Furthermore, the epoxy resin adhesive base film layer 130 and the photothermal conversion layer 120 and adhesive layer 140, which are not bonded to each other, have adhesive properties and have the hardness to support the two layers.

[0099] Furthermore, the adhesive base film layer 130 itself is adhesive, and in the manufacturing process, instead of forming and laminating separate film layers, the photothermal conversion layer 120 and the adhesive layer 140 are directly coated and cured on the adhesive base film layer 130. Therefore, the interlayer adhesion between the adhesive base film layer 130 and the photothermal conversion layer 120, and between the adhesive base film layer 130 and the adhesive layer 140, is very high. For this reason, the adhesive base film layer 130 has excellent heat resistance and excellent process stability even under high temperature and high vacuum conditions.

[0100] Furthermore, the adhesive base film layer 130 includes an adhesive resin. This adhesive resin allows for the formation of a film containing an epoxy resin.

[0101] The adhesive resin may be an elastomer resin. Preferably, the glass transition temperature (Tg) of the adhesive resin may be at least 0°C or higher. An adhesive resin with this glass transition temperature allows the adhesive base film layer 130 to have excellent heat resistance.

[0102] The adhesive resin may be an acrylamide-based or rubber-based elastomer resin. The adhesive resin may include rubber-based polymers or acrylic polymers. For example, the adhesive resin may include nitrile butadiene rubber (NBR) or styrene butadiene rubber (SBR).

[0103] Preferably, when the adhesive resin includes NBR, the adhesive resin may comprise 30 wt% or more of acrylonitrile groups based on the total weight of the adhesive resin. In this case, the adhesive resin is readily soluble in a solvent.

[0104] Preferably, when the adhesive resin comprises an acrylic polymer, the acrylic polymer may comprise at least two or three monomers selected from the group consisting of ethyl acrylate (EA), hydroxyethyl methacrylate (HEMA), hydroxyethyl acrylate (HEA), butyl acrylate (BA), poly(methyl methacrylate) (PMMA), acrylonitrile (AN), and combinations thereof.

[0105] The adhesive resin has a weight average molecular weight (Mw) of about 500,000 to about 1,500,000, more preferably about 700,000 to about 1,000,000, and more preferably 800,000 to 1,000,000. The high molecular weight adhesive resin has heat resistance of the adhesive base film layer 130.

[0106] When the weight-average molecular weight of the adhesive resin is less than about 500,000, the chemical resistance and heat resistance of the adhesive base film layer 130 may be insufficient. In addition, when the weight-average molecular weight of the adhesive resin is greater than about 1,500,000, there is a problem that the adhesive base film layer 130 is difficult to form, and it is difficult to apply because the adhesive resin is not easily soluble in solvents.

[0107] Furthermore, adhesive resins may contain epoxy groups in their chains. The presence of epoxy groups in the adhesive resin chains improves the compatibility between epoxy resins and adhesive resins.

[0108] Preferably, the weight ratio of adhesive resin to epoxy resin in the adhesive base film layer is 25:75 to 55:45. That is, when the total weight of epoxy resin and adhesive resin is 100 parts by weight, epoxy resin is contained in 30 to 60 parts by weight, and adhesive resin is contained in 40 to 70 parts by weight. The weight ratio of adhesive resin to epoxy resin in the adhesive base film layer is preferably 30:70 to 50:50, more preferably 40:60.

[0109] When the total weight of epoxy resin and adhesive resin is 100 parts by weight, if less than 30 parts by weight of epoxy resin are used, the chemical resistance decreases and the rigidity of the adhesive resin film is insufficient, making the subsequent coating of the photothermal conversion layer and adhesive layer difficult. Furthermore, when more than 60 parts by weight of epoxy resin are used, the chemical resistance and rigidity are excellent, but the adhesive resin film becomes brittle and is almost unusable as a support layer.

[0110] Furthermore, the adhesive base film layer 130, including epoxy resin, has adhesive properties to both the photothermal conversion layer 120 and the adhesive layer 140, which are not bonded to each other, and has the hardness to support the two layers.

[0111] The adhesive base film layer 130 may include a curing agent. Preferably, it may include a phenolic curing agent. Typically, amines and isocyanates can be considered as curing agents for epoxy resins, but these curing agents have the problem of being difficult to form a film. The adhesive base film layer 130 can be formed by using a phenolic curing agent as the curing agent and appropriately controlling the curing rate.

[0112] The adhesive base film layer 130 may include a curing catalyst. The curing catalyst is used in an amount that makes the adhesive base film layer 130 chemically resistant to methyl ethyl ketone (MEK), ethyl acrylate (EA), toluene, and xylene, while maintaining its heat resistance. For example, the curing catalyst may be imidazole.

[0113] In addition, the adhesive base film layer 130 may additionally include fillers. For example, the fillers may include at least one selected from the group consisting of TiO2, silica, copper powder, alumina, and carbon black.

[0114] The filler can additionally prevent the shrinkage and expansion of the adhesive base film layer 130. In addition, after the substrate processing is completed, the substrate has additional light-shielding effect when light is irradiated onto the photothermal conversion layer 120.

[0115] The adhesive base film layer 130 can be prepared and subjected to aging for a predetermined period. For example, aging for about 4 days can be performed. As a result, the epoxy group reaction is completely terminated, and the photothermal conversion layer 120 and the adhesive layer 140 are subsequently formed on the adhesive base film layer 130, or their stability is improved during the substrate processing.

[0116] The thickness of the adhesive base film layer 130 is approximately 10 μm to approximately 50 μm, preferably approximately 20 μm to approximately 40 μm, and more preferably approximately 20 μm to approximately 30 μm. When the thickness of the adhesive layer 140 is less than approximately 10 μm, it is difficult to obtain sufficient physical strength, which may make it difficult to support the photothermal conversion layer 120 and the adhesive layer 140, and may be affected by shrinkage that occurs during the curing of the adhesive layer. In addition, when the thickness of the adhesive base film layer 130 is greater than approximately 50 μm, the solvent is difficult to evaporate during coating, irregular pores may form on the film surface, and when solvent remains, the solvent may affect the physical properties of the adhesive film.

[0117] The first pad 110 and the second pad 150 are used to support and protect the adhesive layer 140 and the photothermal conversion layer 120, respectively. When using the adhesive film, the first pad 110 and the second pad 150 are removed.

[0118] The first pad 110 and the second pad 150 may be silicone-coated polyethylene terephthalate (PET), but are not limited to this, and are fully capable of supporting and protecting the adhesive layer 140 and the photothermal conversion layer 120.

[0119] The process for manufacturing an adhesive film according to one embodiment of the present invention is as follows.

[0120] The adhesive base film layer 130 is formed on the first pad. Then, the second pad layer can be pressed onto the adhesive base film layer 130 by a roll-to-roll method.

[0121] Subsequently, while removing the second liner, the polysiloxane-based adhesive layer 140 can be directly formed on the adhesive base film layer 130, and the third liner can be laminated on the adhesive layer 140.

[0122] Subsequently, while removing the first pad, the photothermal conversion layer 120 can be directly formed on other surfaces of the adhesive base film layer 130, and the fourth pad can be laminated onto the photothermal conversion layer 120. That is, in the process, the fourth pad on the photothermal conversion layer 120 and the third pad on the adhesive layer 140 correspond to the first pad 110 and the second pad 150 in FIG. 1, respectively.

[0123] However, the process of fabricating the adhesive film of the present invention is not limited to this, and the method of forming the photothermal conversion layer 120 and the adhesive layer 140 on the two surfaces of the adhesive base film layer 130 in the form of a film is sufficient.

[0124] When using liquid adhesive materials and liquid photothermal conversion materials between a substrate and a support, the process involves applying and curing the photothermal conversion material onto the support to form a photothermal conversion layer, and applying and curing the adhesive material onto the substrate to be processed to form an adhesive layer. Afterward, a process is required to bond the adhesive layer and the photothermal conversion layer under vacuum. In other words, when using liquid materials, there are required coating time, curing time, and bonding time.

[0125] On the other hand, when using an adhesive film in the form of a film according to the invention, the procedure of removing the first pad, attaching the adhesive layer to the substrate, removing the second pad, and attaching the photothermal conversion layer to the support is sufficient. Therefore, according to the invention, it is possible to significantly reduce the time required for the procedure and reduce the costs required for the application procedure, curing procedure, vacuum procedure, and the like.

[0126] Figures 2A to 2C illustrate processed substrates using the adhesive film according to the present invention.

[0127] Referring to FIG2A, in the adhesive film according to the present invention, the first pad is removed and the photothermal conversion layer 120 is attached to the support 200, and the second pad is removed and the adhesive layer 140 is attached to the substrate 300. At this time, the process is preferably performed at about 40°C to about 80°C, thereby increasing the adhesion between the photothermal conversion layer 120 and the support 200.

[0128] The support member 200 is made of a material capable of transmitting radiant energy, such as the laser used in this invention, and is required to keep the substrate 300 flat and prevent damage to the substrate 300 during processing and transport. Preferably, the support member 200 is rigid and transmissive.

[0129] In order for the photothermal conversion layer 120 to decompose, the transmittance of the support 200 is not limited unless the transmittance prevents radiation energy from penetrating into the photothermal conversion layer 120. However, the transmittance can preferably be, for example, about 50% or higher.

[0130] In addition, in order to prevent the substrate from warping during processing, it is preferable that the support 200 has sufficiently high rigidity and that the flexural strength of the support 200 is preferably 2×10-3 (Pa.m3) or higher, more preferably 3×10-2 (Pa.m3) or higher.

[0131] In addition, in order to prevent damage caused by thermal history that may occur during the process performed on the substrate, it is preferable that the support 200 has sufficient heat resistance and that the thermal deflection temperature of the support 200 is preferably 550°C or higher, more preferably 700°C or higher.

[0132] The support member 200 may be, for example, glass. In addition, in order to improve the adhesion strength to adjacent layers (such as photothermal conversion layer 120), the support member 200 may be surface treated with adhesive or the like, if necessary.

[0133] Subsequently, after fixing the substrate 300 and the support member 200 with the adhesive film including the photothermal conversion layer 120, and inserting the adhesive base film layer 130 and the adhesive layer 140 therebetween, the substrate 300 is processed.

[0134] The substrate 300 is fixed to and processed by the support 200, and then separated from the support 200. For example, it may be a wafer or substrate used in a flexible display device.

[0135] As an example, substrate 300 may include semiconductor wafers, crystal wafers, sapphire, or glass, such as silicon and gallium arsenide. The circuit surface of substrate 300 may be bonded to adhesive layer 140. Subsequently, the surfaces of substrate 300 not bonded to adhesive layer 140 may be ground using a grinder or similar method to process them into thinner substrates.

[0136] As another example, substrate 300 may be an epoxy molded wafer. The molded surface of substrate 300 may be bonded to adhesive layer 140, and then, by performing a predetermined process for connecting circuits to the surface of substrate 300 (which is not bonded to adhesive layer 140), the substrate may be processed into a finished substrate.

[0137] On the other hand, as yet another example, substrate 300 may be a plastic substrate, a metal film, or the like, serving as a flexible substrate. For example, substrate 300 may be PI. However, the invention is not limited thereto, and materials with flexible properties are sufficient to be used as substrate materials for flexible display devices.

[0138] For example, "processing" may include a process of forming a component layer on a substrate 300. Although not shown, the component layer consists of a plurality of thin film layers and electrical components, and more specifically, the component layer may include a thin film transistor, which includes a gate electrode, a semiconductor layer, a source electrode, and a drain electrode.

[0139] Flexible display devices may be selected from any of the group consisting of organic light-emitting diode displays, liquid crystal displays, and electrophoretic displays. However, flexible display devices are not limited to these and may include all flexible display devices that use flexible substrates.

[0140] Referring to Figure 2B, after the desired processing level, the support 200 and the processed substrate 300 are separated from each other by laser irradiation 400. Laser 400 is irradiated from the support 200 side.

[0141] The photothermal conversion layer 120 absorbs the radiation energy of the laser 400 and converts it into heat energy. The generated heat energy causes the temperature of the photothermal conversion layer 120 to rise rapidly, and the temperature causes the thermally decomposable resin in the photothermal conversion layer 120 to decompose. The gas produced by thermal decomposition forms a porous layer in the photothermal conversion layer 120, dividing the photothermal conversion layer 120 into two parts, resulting in the separation of the support member 200 and the processed substrate 300.

[0142] The thermally decomposable resin in the photothermal conversion layer 120 is decomposed by irradiation with laser 400, forming cracks within the layer to separate the photothermal conversion layer itself. Air (gas) generated by the resin decomposition is ultimately introduced between the two layers to further separate them. Therefore, to facilitate gas introduction, it is preferable to irradiate the interior of the photothermal conversion layer 120 from its edge.

[0143] To use the laser 400 from the edge of the photothermal conversion layer 120, a method can be used to apply the laser 400 while simultaneously moving it linearly back and forth from the edge, or alternatively, a method can be used to irradiate the laser 400 spirally from the edge to the center (such as a phonograph).

[0144] Laser 400 typically has a wavelength of about 300 to about 11,000 nm, preferably about 300 to about 2,000 nm, and specific examples include YAG lasers (at a wavelength of 1,064 nm), YAG lasers that generate a second harmonic (at a wavelength of 532 nm), and semiconductor lasers (at a wavelength of 780 to 1,300 nm).

[0145] Referring to Figure 2C, after the support 200 is removed, the adhesive base film layer 130 and the adhesive layer 140 on the processed substrate 300 are removed. To remove the adhesive base film layer 130 and the adhesive layer 140, removal tape 500 is preferably used. The removal tape has a stronger adhesion to the adhesive base film layer 130 than the adhesion between the processed substrate 200 and the adhesive layer 140.

[0146] The removal tape 500 is configured to adhere to the adhesive base film layer 130 and then peeled off together with the adhesive base film layer 130 and the adhesive layer 140 to remove the adhesive base film layer 130 and the adhesive layer 140 from the processed substrate 300.

[0147] Although not clearly shown in the figure, after the photothermal conversion layer 120 is separated on the adhesive base film layer 130, a portion of the photothermal conversion layer 120 may remain. When using removal tape 500, the remaining portion is also removed.

[0148] Simultaneously, although not shown in the figure, after the support 200 is removed, a removal solution can be used to remove the adhesive base film layer 130 and the adhesive layer 140. Preferably, the adhesive base film layer 130 and the adhesive layer 140 (with the photothermal conversion layer partially remaining) can be immersed in the removal solution to remove the adhesive base film layer 130 and the adhesive layer 140. Preferably, the adhesive layer 140 can be immersed in the removal solution for approximately 10 seconds to 60 seconds.

[0149] In addition, this removal solution may include trans-1,2-dichloroethylene and hydrofluoroether.

[0150] When the size or area of ​​the processed substrate 200 is large, it may be difficult to remove the adhesive base film layer 130 and the adhesive layer 140 in one go using the remover tape 500. However, when using a removal solution, it is advantageous to remove the adhesive base film layer 130 and the adhesive layer 140, which have a large area. In addition, no additional external physical force is required, and it has the effect of removing the adhesive base film layer 130 and the adhesive layer 140 in a short time without leaving any residue.

[0151] The method for processing substrates according to the present invention is eco-friendly because solvents are not required when processing substrates using the prepared adhesive film. Furthermore, when using the prepared adhesive film, the exposure of the support and substrate to heat and UV is reduced during substrate processing, thereby preventing additional damage.

[0152] Furthermore, the process of directly applying and curing the adhesive material or photothermal conversion material onto the support or substrate can be omitted, thus simplifying the process and reducing costs and time. In addition, the processing method is advantageous for forming adhesive layers and photothermal conversion layers of uniform thickness and can also be used in the processing of large-area substrates.

[0153] The present invention will now be described in more detail through experimental examples. However, these experimental examples are merely illustrative and not intended to limit the invention. That is, embodiments of the present invention can be modified in various ways, and the scope of the present invention should not be construed as limited to the experimental examples described below.

[0154] [Example]

[0155] Preparation Examples

[0156] Preparation Example 1 - Preparation of Adhesive Base Film

[0157] Prepare 40g of solvent (MEK / EA). Add 11g of epoxy resin and 9g of phenolic resin curing agent to the solvent. The ratio of epoxy resin to phenolic resin curing agent is 1:1 by equivalent weight. Stir the solution at 30 RPM for 15 minutes to completely dissolve the solid epoxy resin and phenolic resin.

[0158] 80g of the solids content of the elastomer resin was further added to the solution. The solution was stirred thoroughly at 30 RPM for 30 minutes using the same stirrer to form an epoxy resin / elastomer mixture.

[0159] 0.1 g of imidazole, used as a curing catalyst, was added in equal portions to separate containers, followed by the addition of 10 g of solvent (MEK / EA) to completely dissolve it.

[0160] The dissolved imidazole solution was added to the prepared epoxy / elastomer mixture. The solution was stirred at 30 RPM for 15 minutes using the same stirrer.

[0161] The prepared solution was degassed using a vacuum pump and vacuum dryer for 30 minutes to form a mixture. The mixture was then filtered through a 250-300 mesh filter.

[0162] The filtered solution was coated onto a PET pad, with both surfaces, each 50 μm thick, subjected to release-treated polysiloxane. The coating was applied to the tightly sealed release surfaces. Drying and curing were performed at 130°C for 2 minutes, resulting in a 25 μm thick coated film. The coated film was then wound into rolls for final fabrication.

[0163] The prepared adhesive base film was aged in an aging oven at 45°C for 4 days.

[0164] Preparation Example 2 - Preparation of Adhesive Layer

[0165] Prepare 80 g of solvent (toluene / xylene). Add benzoyl peroxide (BPO) (Pergan) to the solvent. The amount added is 3.5 wt% relative to the solid content of the free radical curable polysiloxane resin added later. Stir the BPO at 10 RPM for 15 minutes to completely dissolve it.

[0166] 100g of polysiloxane resin Q2-7406 (Dow corning, 56.5wt%) was added to the dissolved BPO solution, and the mixture was stirred again for 30 minutes in the same manner. The solution was then degassed using a vacuum pump and a vacuum dryer for 30 minutes to form a mixture. The mixture was then filtered through a 250-300 mesh filter.

[0167] The filtered solution was coated onto the adhesive base film layer prepared in Preparation Example 1. After drying at 180°C for 2 minutes, the filtered solution was coated into a film with a thickness of 30 μm. After drying the coated film, a 50 μm fluorinated release PET liner was bonded to it, and then it was wound into a roll to complete the preparation.

[0168] Preparation Example 3 - Preparation of Photothermal Conversion Layer

[0169] 6 wt% carbon black (Cancarb) (with a particle size of 240 nm), 4 wt% titanium dioxide (Huntsman) (with a particle size of 240 nm), and 1 wt% dispersant (BYK Chemie Japan Co., Ltd.) were added to 75 wt% methyl ethyl ketone (MEK, Samchun Chemical Co., Ltd.), and dispersed using an ultrasonic disperser for 30 minutes to prepare a solution containing a light absorber. 7 wt% of a high molecular weight acrylic elastomer (with a weight average molecular weight of 1,000,000 g / mol and containing 10 mg KOH / g or higher COOH / OH functional groups) replacing PSA and 7 wt% of a low molecular weight acrylic elastomer (with a weight average molecular weight of 500,000 g / mol and containing 5 mg KOH / g or higher COOH / OH functional groups) replacing PSA were mixed and stirred for 30 minutes to prepare a thermodegradable resin. The thermodegradable resin is added to the solution in which the light absorber is dispersed, and then stirred again for 20 minutes. Then, methyl ethyl ketone (MEK) is added to give the mixture a viscosity suitable for coating (200 CPS to 5,000 CPS).

[0170] The solution was coated onto the adhesive base film layer prepared in Preparation Example 1. However, the adhesive layer was coated on the surface opposite to the coated surface, and the PET backing of the adhesive base film layer was removed before coating. After drying at 90°C for 1 minute, the solution was coated into a film with a thickness of 10 μm and then dried.

[0171] Then, the adhesive film is aged in an oven at 45°C for 15 hours to complete the adhesive film.

[0172] Example

[0173] In Preparation Example 1, the adhesive film was prepared by applying the types and amounts of the components shown in the table below. The components and amounts of each example are shown in Table 1 below.

[0174]

[0175]

[0176] The materials used in the table above are as follows.

[0177] Multifunctional epoxy resins: YDCN-500-4P (KUKDO), YDCN-500-8P (KUKDO), KDCP-100 (KUKDO), KDCP-150 (KUKDO), and KDCP-200 (KUKDO).

[0178]

[0179] Bifunctional epoxy resins: YD-011 (KUKDO), YD-012 (KUKDO), YD-017 (KUKDO)

[0180]

[0181] Crystalline epoxy resins: YX4000H (Mitsubishi Chemical Corporation), YSLV-80XY (Nippon Steel & Sumitomo Metal), or YSLV-120TE (Nippon Steel & Sumitomo Metal).

[0182]

[0183] Core-shell epoxy resins: MX-136 (Kaneka), MX-138 (Kaneka), B-tough-A3 (Croda), YP-50 (KUKDO)

[0184] Hardeners (phenolic varnishes): KPH-2001 (Kolon), TD2131 (DIC Corporation), MEH-7800-SS (MEIWA), MEH-7800-4S (MEIWA), MEH-800-SSKC (MEIWA)

[0185] Elastomers (Mw: 300,000 to 1,000,000): NBR (40% acrylonitrile, Kumho Petrochemical), WS-023 (Nagase Chemtex), SG-708-6 (Nagase Chemtex), SG-P3-TEA (Nagase Chemtex).

[0186] Curing catalysts (imidazolium): 2PZ-CN (Shikoku), 2PZ-PW (Shikoku), 2PHZ-PW (Shikoku)

[0187] Packing materials: CUSP03 (JoinM), CUSP05 (JoinM), Sterling 1120 (Cabot), Thermax N990 (Cancab), TR72 (Huntsman) and TR92 (Huntsman), R972, SO31R

[0188] Dispersant: BYK111(BYK), DISPERBYK-161(BYK), BYK2131(BYK), BYK2150(BYK), KD6(Croda), KD8(Croda), KD9(Croda)

[0189] Table 2 below shows the experimental results for Examples 1 to 9.

[0190]

[0191]

[0192] Referring to Table 2, in Example 1 where no adhesive resin was applied, it was confirmed that epoxy resin alone was very brittle, difficult to coat, and unable to form a film on its own. Furthermore, even in Example 9, without a certain ratio of multifunctional epoxy resin, the film was very brittle and failed to form a film. In addition, in Examples 2 and 3 where epoxy resin was not included, chemical resistance was insufficient, therefore, the adhesive base film layer dissolved when the photothermal conversion layer was coated. Furthermore, as in Example 7, it was confirmed that even with epoxy resin, when the amount of multifunctional epoxy resin was too small, the epoxy resin had low hardness, therefore, the film did not have sufficient chemical resistance in solvents such as methyl ethyl ketone (MEK).

[0193] On the other hand, referring to Examples 4 and 5, when additional fillers are included, it may impart membrane rigidity and inhibit shrinkage.

[0194] While embodiments of the present invention have been described above, they are merely examples, and those skilled in the art will understand that various modifications and equivalent embodiments can be implemented therefrom. Therefore, the scope of protection of this invention should be interpreted to include not only the claims described below, but also their equivalents.

Claims

1. An adhesive film comprising: an adhesive layer; a photothermal conversion layer containing a light absorber and a thermally decomposable resin; and an adhesive base film layer disposed between the adhesive layer and the photothermal conversion layer, wherein the adhesive base film layer contains a multifunctional epoxy resin, an adhesive resin, a curing agent, and a curing catalyst, wherein the adhesive resin is an acrylamide-based or rubber-based elastomer resin, and wherein the weight ratio of the adhesive resin to the epoxy resin in the adhesive base film layer is 25:75 to 55:

45.

2. The adhesive film of claim 1, wherein the adhesive layer is an adhesive layer based on silicon.

3. The adhesive film of claim 1, wherein the thermally decomposable resin contains two acrylic resins having -COOH or -OH functional groups and different weight average molecular weights.

4. The adhesive film of claim 1, wherein the adhesive base film layer has adhesive properties to both the adhesive layer and the photothermal conversion layer.

5. The adhesive film as requested in item 1, wherein the curing agent is a phenolic curing agent.

6. The adhesive film of claim 1, wherein the adhesive resin is an elastomeric resin having a weight average molecular weight of 500,000 to 1,500,000.

7. The adhesive film of claim 1, wherein the adhesive resin has epoxy groups in its chain.

8. The adhesive film of claim 1, wherein the adhesive base film layer further comprises filler.

9. The adhesive film of claim 8, wherein the filler comprises at least one selected from the group consisting of TiO2, silica, copper powder, alumina, and carbon black.

10. The adhesive film of claim 1, wherein the curing catalyst of the adhesive base film layer is imidazole.

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