Pattern forming method and pattern forming structure

Abstract

This pattern formation method comprises: a laminating step for laminating a curable resin layer 3 and a support film 4 on a substrate 2; a curing step for curing the entire curable resin layer 3; a peeling step for peeling the support film 4 from the curable resin layer 3 after curing; a machining step for irradiating an excimer laser light 15 via a mask 14 on the curable resin layer 3 after peeling of the support film 4, and machining a prescribed pattern on the curable resin layer 3; and a forming step for, after forming a plating layer 17 using the curable resin layer 3 with the prescribed pattern as a mask, removing the curable resin layer 3, and forming a wiring pattern 16 on the substrate 2 using the plating layer 17.

Description

[Technical field]

[0001] The present disclosure relates to patterning methods and structures. [Background technology]

[0002] In recent years, electronic devices have become smaller, lighter, and more multifunctional. This has led to greater integration of LSIs and chip components, and their configurations have become smaller and have more pins. This has created a demand for higher density and precision in the semiconductor elements, semiconductor packages, printed wiring boards, flexible wiring boards, and other components that make up these components.

[0003] A conventional pattern forming method is a semi-additive process. In this method, an electroless plating layer is formed on an insulating layer, and a resist layer of a predetermined pattern is formed on the electroless plating layer using a photosensitive dry film. Then, an electroplating layer is formed, and the resist layer is peeled off and the electroless plating layer is removed to form wiring having a desired pattern on a substrate. However, when making the pattern finer, there is a problem in that defects in the pattern caused by foreign matter such as particles or deposits contained in the support film (PET film) supporting the photosensitive dry film become noticeable.

[0004] To address these problems, a method of forming a pattern using laser ablation processing has been attracting attention. For example, in the method of forming a solder resist described in Patent Document 1, a semi-cured curable resin having a support film is formed on a substrate. Next, a laser beam is irradiated from above the support film to form a via hole in the semi-cured curable resin. After that, the support film is peeled off, and the semi-cured curable resin layer is cured. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] International Publication No. 2012 / 042846 Summary of the Invention [Problem to be solved by the invention]

[0006] However, even when a pattern is formed using laser ablation processing as in Patent Document 1, there remains a possibility that the laser light is refracted by particles or deposits contained in the support film, causing defects in the formed pattern. In addition, in the method of Patent Document 1, the laser light is irradiated from above the support film, so holes are formed in the support film during the laser ablation processing. From the perspective of the Sustainable Development Goals (SDGs), it is desirable to have a method that allows the support film to be reused.

[0007] The present disclosure has been made to solve the above-mentioned problems, and aims to provide a pattern formation method and a pattern formation structure that enable highly accurate patterning in accordance with sustainable development goals. [Means for solving the problem]

[0008] A pattern forming method according to one aspect of the present disclosure includes a lamination step of laminating a curable resin layer and a support film onto a substrate, a curing step of curing the entire curable resin layer, a peeling step of peeling the support film from the cured curable resin layer, a processing step of irradiating the curable resin layer after the support film has been peeled off with excimer laser light via a mask to process the curable resin layer into a predetermined pattern, and a formation step of forming a plating layer using the curable resin layer of the predetermined pattern as a mask, and then removing the curable resin, and forming a wiring pattern on the substrate using the plating layer.

[0009] In this pattern forming method, the entire curable resin layer is cured before processing the curable resin layer into a predetermined pattern with excimer laser light, and the support film is peeled off from the curable resin layer after curing. Therefore, when processing the cured curable resin layer, refraction of the excimer laser light at the curable resin layer and refraction of the excimer laser light caused by particles, deposits, etc. contained in the support film can be suppressed. Therefore, the occurrence of defects in the curable resin layer during processing is suppressed, and a highly accurate wiring pattern can be formed on the substrate. In addition, in this pattern forming method, since the support film is peeled off from the curable resin layer before irradiation with excimer laser light, it is possible to avoid holes being made in the support film by the excimer laser light. This makes it easy to reuse the support film used in the process, which can contribute to the realization of patterning in accordance with the sustainable development goals.

[0010] The support film may be a recycled PET film. In this pattern formation method, since the entire curable resin layer is cured, the support film does not require high transparency whether the curable resin layer is cured by photocuring or by heat curing. Therefore, the use of a recycled PET film as the support film can further contribute to the realization of patterning in accordance with the sustainable development goals.

[0011] The line and space L / S of the wiring pattern may be 5 / 5 μm or less. As described above, this pattern forming method suppresses the occurrence of damage to the curable resin layer during the processing step. Therefore, it is suitable for forming a fine wiring pattern with a line and space L / S of 5 / 5 μm or less.

[0012] The aspect ratio of the wiring pattern (the ratio of the height of the wiring pattern to the line width of the wiring pattern) may be 0.5 to 20. As described above, this pattern formation method can suppress the occurrence of damage to the curable resin layer during the processing step. Therefore, it is suitable for forming a fine wiring pattern with an aspect ratio of 0.5 to 20.

[0013] The curable resin layer may be made of a photocurable resin, in which case the entire curable resin layer can be easily cured by light irradiation.

[0014] The curable resin layer may be made of a thermosetting resin, in which case the entire curable resin layer can be cured simply by heating.

[0015] A pattern forming structure according to one aspect of the present disclosure comprises a substrate, a curable resin layer laminated on the substrate, and a support film laminated on the curable resin layer, the support film being a recycled PET film.

[0016] In this pattern formation structure, the entire curable resin layer is cured before processing the curable resin layer into a predetermined pattern with excimer laser light, and the support film can be peeled off from the curable resin layer after curing. Therefore, when processing the cured curable resin layer, refraction of the excimer laser light at the curable resin layer and refraction of the excimer laser light caused by particles, deposits, etc. contained in the support film can be suppressed. Therefore, the occurrence of defects in the curable resin layer during processing is suppressed, and a highly accurate wiring pattern can be formed on the substrate. In addition, in this pattern formation structure, the support film is a recycled PET film. Using a recycled PET film as the support film can contribute to the realization of patterning in accordance with the sustainable development goals. Effect of the Invention

[0017] The present disclosure enables patterning with high precision and in line with sustainable development goals. [Brief description of the drawings]

[0018] [Figure 1] FIG. 1 is a schematic cross-sectional view showing a pattern formation structure according to an embodiment of the present disclosure. [Diagram 2] 1 is a flowchart illustrating a pattern formation method according to an embodiment of the present disclosure. [Diagram 3]FIG. 4 is a schematic cross-sectional view showing a lamination process. [Figure 4] FIG. 4 is a schematic cross-sectional view showing a curing step. [Diagram 5] 5A to 5C are schematic cross-sectional views showing a peeling step. [Figure 6] 5A to 5C are schematic cross-sectional views showing processing steps. [Figure 7] FIG. 7 is a schematic cross-sectional view showing a step subsequent to that shown in FIG. 6. [Figure 8] 5A to 5C are schematic cross-sectional views showing a forming process. [Figure 9] 9 is a schematic cross-sectional view showing a step subsequent to that shown in FIG. 8. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0019] Hereinafter, preferred embodiments of a pattern formation method and a pattern formation structure according to one aspect of the present disclosure will be described in detail with reference to the drawings.

[0020] Fig. 1 is a schematic cross-sectional view showing a pattern formation structure according to an embodiment of the present disclosure. As shown in Fig. 1, the pattern formation structure 1 includes a substrate 2, a curable resin layer 3 laminated on the substrate 2, and a support film 4 laminated on the curable resin layer 3. The substrate 2 is a member on which a wiring pattern 16 (see Fig. 9) is formed. The substrate 2 is also an adherend for the curable resin layer 3. Examples of the substrate 2 include a silicon wafer, a silicon wafer with a film on which a metal such as Cu is vapor-deposited, and a copper-clad laminate.

[0021] The curable resin layer 3 is composed of, for example, a photocurable resin or a thermosetting resin. Here, the curable resin layer 3 is composed of a negative photocurable resin 11. The photocurable resin 11 may be in the form of a film, or may be applied in the form of a liquid. The liquid photocurable resin 11 is produced by stirring each material. There is no particular limitation on the stirring (dispersion) method, but the materials may be stirred by applying heat or the like, or may be stirred in an inert gas atmosphere, a reduced pressure atmosphere, or a pressurized atmosphere. Foreign matter can be removed by filtering the resin composition after stirring. The film-like photocurable resin 11 is provided in a state in which, for example, a solution of the photocurable resin composition is uniformly applied to a support film and dried.

[0022] In order to achieve a high etching rate during the laser ablation process described below, the photocurable resin 11 is designed taking into consideration 1) the ease with which molecular bonds are broken when irradiated with laser light, and 2) the absorbency for the wavelength of laser light. To satisfy 1), a compound with lower molecular bond energy is selected. To satisfy 2), a component that absorbs the wavelength of laser light is included. The photocurable resin 11 contains a polymerizable compound as component (A) and an ultraviolet absorber as component (B). Either component (A) or component (B) may be contained in a larger amount, or may be mixed with other components.

[0023] The polymerizable compound is selected on the assumption that it will be polymerized after laminating the photocurable resin 11 on the substrate 2. By polymerizing after lamination, the lamination property or coating property before lamination can be secured, and tackiness after polymerization can be suppressed. For example, a compound having a polymerizable ethylenically unsaturated bond in the molecule is used as the polymerizable compound. For example, the (A) component can be a (meth)acrylic resin, a urethane acrylate, an epoxy acrylate, etc. From the viewpoint of low molecular bond energy, the (A) component may be a non-aromatic photopolymerizable compound. Even when the (A) component is mixed with an aromatic compound, or when a part of the (A) component contains an aromatic functional group, a high etching rate during laser ablation processing can be achieved by adjusting the ratio.

[0024] The ultraviolet absorbing agent is not particularly limited as long as it is a component that absorbs light of a desired wavelength. For example, known absorbents that can absorb laser light such as ArF (wavelength: 193 nm), KrF (wavelength: 248 nm), XeCl (wavelength: 308 nm), and XeF (wavelength: 351 nm) can be used as the ultraviolet absorbing agent. Examples of such absorbents include benzotriazole-based absorbents, triazine-based absorbents, salicylic acid derivative-based absorbents, and benzophenone-based absorbents.

[0025] The ultraviolet absorber may have a polymerizable unsaturated group. The ultraviolet absorber is classified into a type that generates radicals by absorbing ultraviolet light and a type that does not generate radicals by absorbing ultraviolet light. The ultraviolet absorber that generates radicals contains a photopolymerization initiator. By containing a photopolymerization initiator, the photocurable resin 11 can be cured with ultraviolet light before and after the laser ablation process, and the handleability of the pattern formation structure 1 can be improved.

[0026] Examples of the photopolymerization initiator include aromatic ketones such as 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)-butanone-1 and 2-methyl-1-[4-(methylthio)phenyl-2-morpholino-propanone-1, quinones such as alkyl anthraquinone, benzoin ether compounds such as benzoin alkyl ether, benzoin compounds such as benzoin and alkyl benzoin, benzyl derivatives such as benzyl dimethyl ketal, 2,4,5-triarylimidazole dimers such as 2-(o-chlorophenyl)-4,5-diphenylimidazole dimer and 2-(o-fluorophenyl)-4,5-diphenylimidazole dimer, and acridine derivatives such as 9-phenylacridine and 1,7-bis(9,9'-acridinyl)heptane. The photopolymerization initiator may be used alone or in combination of two or more of these.

[0027] When a film-like photocurable resin 11 is used, the photocurable resin 11 may contain a binder polymer from the viewpoint of film formability. From the viewpoint of storage stability, the binder polymer is preferably a material having compatibility with the (A) component and the (B) component. The binder polymer may be a component that is softer than the polymerizable compound of the (A) component. This ensures flexibility of the curable resin layer 3 after curing. As the binder polymer, for example, a (meth)acrylic resin, a urethane resin, an epoxy resin, an amide resin, an amide epoxy resin, an alkyd resin, a polyimide resin, or the like is used. Among these resins, it is preferable to use a (meth)acrylic resin from the viewpoint of contributing to the rate of laser ablation processing, that is, from the viewpoint of low molecular bond energy.

[0028] As the binder polymer, it is preferable to select a resin type whose basic skeleton is non-aromatic from the viewpoint of low molecular binding energy. Here, the non-aromatic basic skeleton means that the basic skeleton that is repeated multiple times by polymerization does not contain aromatics, and does not mean aromatics that are located only at the terminals, etc. Aromatic binder polymers and aliphatic polymers may be mixed to balance the etching rate.

[0029] The molecular weight of the binder polymer varies depending on the state of the photocurable resin 11. When a film-like photocurable resin 11 is used, the molecular weight may be selected so as to balance, for example, the film formability of the film and the rate of the laser ablation processing. By ensuring a sufficient molecular weight, it is possible to ensure film formability and to prevent dripping during film formation and storage. By not making the molecular weight excessive, it is possible to prevent a decrease in the rate of the laser ablation processing. When a liquid photocurable resin 11 is used, the rate of the laser ablation processing can be increased by designing the molecular weight to be as low as possible within the range that can be applied.

[0030] The photocurable resin 11 may contain a thermal curing accelerator. The thermal curing accelerator is not particularly limited as long as it can thermally cure the photocurable resin composition, and can be appropriately selected from commonly used thermal curing accelerators. By adding a thermal curing accelerator, the photocurable resin 11 can be cured at a lower temperature, and the handleability of the pattern-forming structure 1 can be improved. Examples of the thermal curing accelerator include imidazoles, dicyandiamide derivatives, dicarboxylic acid dihydrazide, triphenylphosphine, tetraphenylphosphonium tetraphenylborate, 2-ethyl-4-methylimidazole-tetraphenylborate, and 1,8-diazabicyclo[5,4,0]undecene-7-tetraphenylborate. The thermal curing accelerator may be used alone or in combination of two or more of them.

[0031] The photocurable resin 11 may contain a polymerization inhibitor. By containing the polymerization inhibitor in the photocurable resin 11, the shelf life and work life of the photocurable resin composition can be extended. In addition, unnecessary polymerization during laser ablation processing can be suppressed. The unnecessary polymerization here means that radicals are generated from the photopolymerization initiator by the laser light during laser ablation processing, and polymerization proceeds. As the polymerization inhibitor, a material that has a polymerization inhibitor effect against radical polymerization is used. As the polymerization inhibitor, for example, catechols such as t-butylcatechol, hydroquinones such as hydroquinone, methylhydroquinone, t-butylhydroquinone, and p-methoxyphenol, alkoxyquinones such as methoquinone, and benzoquinones such as p-benzoquinone, methyl-p-benzoquinone, and t-butyl-p-benzoquinone can be mentioned.

[0032] The photocurable resin 11 may contain a solvent. When a liquid photocurable resin 11 is used, it is preferable that the photocurable resin 11 contains a solvent from the viewpoint of ease of viscosity adjustment and ease of manufacturing and inspection. When a film-like photocurable resin 11 is used, it is preferable that the solvent content is small. Solvent that cannot be completely removed during processes such as coating and drying may remain in the photocurable resin 11.

[0033] The photocurable resin 11 may contain, as necessary, dyes such as malachite green, Victoria Pure Blue, brilliant green, and methyl violet, photocoloring agents such as leuco crystal violet, diphenylamine, benzylamine, triphenylamine, diethylaniline, and o-chloroaniline, thermal coloring inhibitors, plasticizers such as p-toluenesulfonamide, pigments, fillers, defoamers, flame retardants, stabilizers, adhesion agents, leveling agents, peeling promoters, antioxidants, fragrances, imaging agents, and thermal crosslinking agents. These components may be contained in an amount of about 0.01 to 20 parts by mass each relative to 100 parts by mass of the total solid content of the (A) component and the (B) component. These materials may be used alone or in combination of two or more.

[0034] The support film 4 is made of a polymer film having heat resistance and solvent resistance, such as polyolefins such as polypropylene and polyethylene, and polyesters such as polyethylene terephthalate. Of these films, it is preferable to use a polyethylene terephthalate (PET) film from the viewpoint of transparency. The PET film contains particles for improving the flowability and releasability during molding of the PET film. Examples of the particles that can be used include inorganic particles such as calcium carbonate, calcium phosphate, silica, kaolin, talc, titanium dioxide, alumina, barium sulfate, calcium fluoride, lithium fluoride, zeolite, and molybdenum sulfide, organic particles such as ion exchange resins, crosslinked polymers, and calcium oxalate, and precipitated particles generated during polyester polymerization.

[0035] In this embodiment, the support film 4 is a recycled PET film 12. The particles of the recycled PET film 12 can be contained in an amount of, for example, about 1 to 10 parts by mass per 100 parts by mass of the PET film. The transparency of the recycled PET film 12 is, for example, less than 1.5. The transparency can be measured, for example, by an integrating sphere turbidity meter.

[0036] Next, a pattern forming method using the above-mentioned pattern forming structure 1 will be described in detail.

[0037] 2 is a flowchart showing a pattern formation method according to an embodiment of the present disclosure. As shown in FIG. 2, the pattern formation method includes a lamination step (step S01), a curing step (step S02), a peeling step (step S03), a processing step (step S04), and a formation step (step S05).

[0038] The lamination step S01 is a step of laminating a curable resin layer 3 and a support film 4 on a substrate 2, as shown in Fig. 3. The method of laminating onto the substrate 2 differs depending on whether the photocurable resin 11 is in liquid form or in film form. When the photocurable resin 11 is in liquid form, the photocurable resin 11 can be laminated by applying a photocurable resin composition onto the substrate 2 and drying it. Examples of methods for applying the photocurable resin composition include a spray method, a roll coating method, a spin coating method, a slit die coating method, a bar coating method, an inkjet method, a screen printing method, a gravure coating method, a curtain coating method, and a knife coating method.

[0039] The film thickness of the photocurable resin 11 before drying is preferably set to be larger than the target value, taking into consideration the reduction in film thickness due to the volatilization of the solvent during drying and the flow of the photocurable resin composition. In order to reduce the film thickness of the photocurable resin 11 after drying, the photocurable resin composition may contain a large amount of solvent, and the film thickness reduction rate during drying may be increased by the volatilization of the solvent. The remaining solvent rate after drying may be 10% by mass or less, 5% by mass or less, or 2% by mass or less.

[0040] The film thickness of the photocurable resin 11 after drying is, for example, 1 to 200 μm. The film thickness of the photocurable resin 11 after drying may be 5 to 100 μm, or may be 10 to 50 μm. By making the film thickness 1 μm or more, coating can be easily realized industrially. By making the film thickness 200 μm or less, it is possible to suppress insufficient evaporation of the solvent and the occurrence of abnormal appearance. When making the film thickness 100 μm or more, a method of coating the photocurable resin composition to a film thickness of 100 μm or less and then laminating two or more photocurable resin composition layers together may be adopted.

[0041] The photocurable resin 11 formed by coating or the like may be heated at 50 to 250°C. The heating temperature may be 50 to 200°C. The heating may be performed in an inert atmosphere such as nitrogen, or may be performed under reduced pressure conditions. There is no particular limit to the drying time. The drying history may include temperature rise and fall, or may be at a constant temperature. When drying including temperature rise and fall is performed, the surface of the photocurable resin 11 after drying tends to be flatter.

[0042] When the photocurable resin 11 is in the form of a film, the photocurable resin 11 can be laminated by heating the photocurable resin 11 while pressing it against the substrate 2. From the viewpoint of adhesion and conformability to the substrate 2, the photocurable resin 11 may be pressed under reduced pressure. The heating temperature may be, for example, room temperature to 130° C. The pressure during pressing may be, for example, about 0.01 to 1.0 MPa (0.1 to 10 kgf / cm). 2 In order to further improve the lamination property, a preheating treatment of the substrate 2 and a heat treatment after lamination may be performed.

[0043] The curing step S02 is a step of curing the entire curable resin layer 3. In the curing step S02, as shown in FIG. 4, the entire surface of the photocurable resin 11 is irradiated with light 13 through the support film 4 to cure the entire photocurable resin 11. The light 13 is, for example, ultraviolet light. As a light source for the light 13, for example, an ultraviolet lamp can be used. The irradiation intensity of the light 13 is, for example, 1 to 100 mW. The irradiation time of the light 13 is, for example, 1 to 1000 seconds.

[0044] Here, curing means that the curable resin layer 3 is completely or almost completely cured. The curing rate F of the curable resin layer 3 after the curing step is, for example, 50% to 100%. The curing rate F may be 85% or more, or 90% or more. The curing rate F is calculated by F=((T1-T2) / T1)×100, where T1 is the curing time of the curable resin composition in solution, and T2 is the curing time of the curable resin composition after the curing step. The curing time is measured, for example, in accordance with JIS C 6521, item 5.7 "Curing time test".

[0045] The peeling step S03 is a step of peeling the support film 4 from the cured curable resin layer 3, as shown in Fig. 5. The peeling of the support film 4 from the curable resin layer 3 is performed, for example, by an auto peeler. The peeled support film 4 can be reused for forming a wiring pattern on another substrate. When a film-like photocurable resin 11 is used in the lamination step, the peeled support film 4 may be reused as a support film for the photocurable resin 11.

[0046] The processing step S04 is a step of processing the curable resin layer 3 into a predetermined pattern. In the processing step, as shown in FIG. 6, the curable resin layer 3 after the support film 4 is peeled off is irradiated with excimer laser light 15 through a mask 14 to process the curable resin layer 3 into a predetermined pattern. That is, in the processing step, the excimer laser light 15 is used to perform laser ablation processing on the cured curable resin layer 3. Here, as shown in FIG. 7, the curable resin layer 3 after the support film 4 is peeled off is processed into a line shape, and a mask for forming a plating layer in the subsequent forming step S05 is formed on the substrate 2.

[0047] Examples of light sources for the excimer laser light 15 include an F2 excimer laser (wavelength: 157 nm), an ArF excimer laser (wavelength: 193 nm), a KrF excimer laser (wavelength: 248 nm), a XeCl excimer laser (wavelength: 308 nm), and a XeF excimer laser (wavelength: 351 nm). In general, the higher the energy density of the excimer laser light 15 per shot on the surface of the curable resin layer 3, the higher the rate of the laser ablation processing. However, when the energy density reaches a certain level or higher, the rate of the laser ablation processing is saturated. Depending on the processing area or the cost of the processing device, taking into consideration the above circumstances, the energy density of the excimer laser light 15 per shot on the surface of the curable resin layer 3 is, for example, 10 to 2000 mJ / cm. 2 and may be 100 to 1500 mJ / cm 2 may be also possible.

[0048] A focusing optical system or an imaging optical system can be used as the optical system of the excimer laser light 15. When processing the curable resin layer 3 into a predetermined pattern, it is preferable to use an imaging optical system from the viewpoint of throughput. The reduction projection magnification of the imaging optical system may be, for example, 1 to 300 times, or 1 to 20 times.

[0049] The forming step S05 is a step of forming the wiring pattern 16 on the substrate. In the forming step, as shown in FIG. 8, a plating layer 17 is formed using a predetermined pattern of the curable resin layer 3 as a mask. Examples of materials constituting the plating layer 17 include Cu, Ni, and Sn. For example, electroplating can be used as a method for forming the plating layer 17. When forming the plating layer 17, a desmear process may be performed on the surface of the substrate 2 in advance, and a seed layer for forming the plating layer 17 may be provided on the surface.

[0050] After the plating layer 17 is formed, the curable resin layer 3 is removed, and a wiring pattern 16 made of the plating layer 17 is formed on the substrate 2, as shown in Fig. 9. When a seed layer is formed on the surface of the substrate 2, the seed layer is removed by etching or the like after removing the curable resin layer 3, and the wiring patterns 16, 16 are electrically separated from each other. Methods for removing the curable resin layer 3 include, for example, a wet stripping method using an inorganic alkaline aqueous solution or an organic alkaline aqueous solution and an organic solvent, and a dry etching method using plasma treatment.

[0051] Examples of the base of the alkaline aqueous solution used in the wet stripping method include alkali hydroxides such as lithium, sodium or potassium hydroxide, alkali carbonates such as lithium, sodium, potassium or ammonium carbonates and bicarbonates, alkali metal phosphates such as potassium phosphate and sodium phosphate, alkali metal pyrophosphates such as sodium pyrophosphate and potassium pyrophosphate, borax (sodium tetraborate), sodium metasilicate, tetramethylammonium hydroxide, ethanolamine, ethylenediamine, diethylenetriamine, 2-amino-2-hydroxymethyl-1,3-propanediol, 1,3-diamino-2-propanol, morpholine, etc. Examples of the wet stripping method include methods using a dip method, a paddle method, a spray method, brushing, slapping, scrubbing, and rocking immersion.

[0052] In this embodiment, the line and space L / S of the wiring pattern 16 obtained after the formation process is 5 / 5 μm or less. That is, in this embodiment, the line width L of the wiring pattern 16 is 5 μm or less, and the space S between adjacent wiring patterns 16, 16 is 5 μm or less. In this embodiment, the aspect ratio of the wiring pattern 16 (the ratio of the height H of the wiring pattern 16 to the line width L of the wiring pattern 16) is 0.5 to 20. The aspect ratio of the wiring pattern 16 may be 1 to 10.

[0053] As described above, in this pattern forming method, the entire curable resin layer 3 is cured before processing the curable resin layer 3 into a predetermined pattern with the excimer laser light 15, and the support film 4 is peeled off from the curable resin layer 3 after curing. Therefore, when processing the cured curable resin layer 3, refraction of the excimer laser light 15 at the curable resin layer 3 and refraction of the excimer laser light 15 caused by particles, deposits, etc. contained in the support film 4 can be suppressed. Therefore, the occurrence of defects in the curable resin layer 3 during processing can be suppressed, and a highly accurate wiring pattern 16 can be formed on the substrate 2. In addition, in this pattern forming method, since the support film 4 is peeled off from the curable resin layer 3 before irradiation with the excimer laser light 15, it is possible to avoid holes being made in the support film 4 by the excimer laser light 15. This makes it easy to reuse the support film 4 used in the process, which can contribute to realizing patterning in accordance with the sustainable development goals.

[0054] In this embodiment, the support film 4 is a recycled PET film 12. In this pattern formation method, since the entire curable resin layer 3 is cured, whether the curable resin layer 3 is cured by photocuring or by heat curing, the support film 4 does not require high transparency. Therefore, using the recycled PET film 12 as the support film 4 can further contribute to realizing patterning in accordance with the sustainable development goals.

[0055] In this embodiment, the line and space L / S of the wiring pattern 16 is 5 / 5 μm or less. As described above, this pattern forming method suppresses the occurrence of defects in the curable resin layer 3 during the processing step. Therefore, it is suitable for forming a fine wiring pattern 16 with a line and space L / S of 5 / 5 μm or less.

[0056] In this embodiment, the aspect ratio of the wiring pattern 16 is 0.5 to 20. As described above, this pattern formation method can suppress the occurrence of damage to the curable resin layer during processing, and is therefore suitable for forming a fine wiring pattern with an aspect ratio of 0.5 to 20.

[0057] In this embodiment, the curable resin layer 3 is composed of a photocurable resin 11. This allows the entire curable resin layer 3 to be cured simply by irradiating it with light.

[0058] In addition, in the pattern formation structure 1, the entire curable resin layer 3 can be cured before processing the curable resin layer 3 into a predetermined pattern with the excimer laser light 15, and the support film 4 can be peeled off from the curable resin layer 3 after curing. Therefore, when processing the cured curable resin layer 3, refraction of the excimer laser light 15 at the curable resin layer 3 and refraction of the excimer laser light 15 caused by particles, deposits, etc. contained in the support film 4 can be suppressed. Therefore, the occurrence of defects in the curable resin layer 3 during processing is suppressed, and a highly accurate wiring pattern 16 can be formed on the substrate. In addition, in the pattern formation structure 1, the support film 4 is a recycled PET film 12. Using the recycled PET film 12 as the support film 4 can contribute to realizing patterning in accordance with the sustainable development goals.

[0059] The present disclosure is not limited to the above embodiment. For example, in the above embodiment, the support film 4 is the recycled PET film 12, but the support film 4 may be a PET film before recycling. The pattern forming method may be performed for the first time using a PET film before recycling, and the PET film 12 obtained by recycling the PET film may be used for the second or subsequent times.

[0060] The curable resin layer 3 may be made of a thermosetting resin. In this case, the entire curable resin layer 3 can be easily cured by heating. As the thermosetting resin, for example, a phenol resin, an epoxy resin, a melamine resin, an alkyd resin, a silicone resin, a thermosetting polyimide, or the like can be used. When a thermosetting resin is used, the curing conditions in the curing step S02 can be, for example, a temperature of 120° C. or higher in an oven for 30 minutes or longer. [Explanation of symbols]

[0061] 1...Pattern formation structure, 2...Substrate, 3...Curable resin layer, 4...Support film, 11...Photocurable resin, 12...Recycled PET film, 14...Mask, 15...Excimer laser light, 16...Wiring pattern, 17...Plating layer.

Claims

1. a lamination step of laminating a curable resin layer and a support film on a substrate; a curing step of curing the entire curable resin layer; a peeling step of peeling the support film from the cured curable resin layer; a processing step of irradiating the curable resin layer after the support film is peeled off with an excimer laser beam through a mask to process the curable resin layer into a predetermined pattern; a forming step of forming a plating layer using the curable resin layer of the predetermined pattern as a mask, and then removing the curable resin to form a wiring pattern on the substrate using the plating layer.

2. 2. The method for forming a pattern according to claim 1, wherein the support film is a recycled PET film.

3. 2. The pattern forming method according to claim 1, wherein the line and space L / S of the wiring pattern is 5 / 5 [mu]m or less.

4. 2. The method for forming a pattern according to claim 1, wherein the aspect ratio of the wiring pattern is 0.5 to 20.

5. 5. The method for forming a pattern according to claim 1, wherein the curable resin layer is made of a photocurable resin.

6. 5. The method for forming a pattern according to claim 1, wherein the curable resin layer is made of a thermosetting resin.

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