Method for producing fine pattern using photosensitive resin composition

Abstract

To provide a method for producing a fine pattern having both uniform coating properties and swelling resistance.SOLUTION: There is provided a method for producing a fine pattern which comprises a first step of forming a photosensitive resin layer 11 on a substrate 1 and a second step of exposing and developing the photosensitive resin layer 11 to form a fine pattern 2, wherein the photosensitive resin layer 11 is formed using a photosensitive resin composition comprising an epoxy resin, a fluorine compound, a photo-cationic polymerization initiator, and a solvent, the boiling point or sublimation point of the fluorine compound is 200°C or higher, the solvent includes an ester solvent and the ratio of the ester solvent in the total solvent is 5 mass% or more.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a method for producing a fine pattern using a photosensitive resin composition. [Background technology]

[0002] In the field of advanced devices such as semiconductor elements and display panels, a method has been proposed in which a photosensitive material film is processed into a fine pattern by photolithography technology and the fine pattern is given functionality. In particular, a method for giving a member solvent resistance is required to prevent pattern deformation due to use in a liquid-contacting environment, and a surface treatment agent for photolithography that gives high water and oil repellency is known. In addition, as a method for more effectively giving a member solvent resistance, Patent Document 1 proposes a method for producing a cured product by curing both a fluorine-containing resin and a curable resin, thereby increasing the swelling resistance of the entire cured product. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent Publication No. 10-219186 Summary of the Invention [Problem to be solved by the invention]

[0004] However, in the method described in Patent Document 1, when the resin composition is cured by heat treatment at high temperature, the fluorine compound may decompose or volatilize, and the desired performance may not be achieved. Therefore, it is necessary to increase the amount of the fluorine compound added to the resin composition, but generally, fluorine compounds with high swelling resistance have low compatibility with organic resins such as photosensitive resins, and there is a problem that they tend to deteriorate the coating property and patterning. Therefore, the present invention aims to provide a method for producing a fine pattern that combines high pattern accuracy and swelling resistance. [Means for solving the problem]

[0005] To achieve the above object, the present invention includes a first step of forming a photosensitive resin layer on a substrate; a second step of exposing and developing the photosensitive resin layer to form a fine pattern; A method for producing a fine pattern comprising: the photosensitive resin layer is formed using a photosensitive resin composition containing an epoxy resin, a fluorine compound, a photocationic polymerization initiator, and a solvent; A method for producing a fine pattern, wherein the boiling point or sublimation point of the fluorine compound is 200° C. or higher, and the solvent contains an ester solvent, the proportion of the ester solvent in the total solvent being 5 mass % or higher. Effect of the Invention

[0006] According to the present invention, it is possible to provide a fine pattern having high pattern accuracy and high swelling resistance. [Brief description of the drawings]

[0007] [Figure 1] 1 is a perspective view showing one embodiment of a fine pattern formed by a method according to the present invention. [Diagram 2] 1A to 1C are cross-sectional views showing steps of a method for manufacturing a fine pattern according to the present invention. [Diagram 3] 1A is a schematic perspective view showing the configuration of a liquid ejection head, and FIG. 1B is a schematic cross-sectional view taken along line AB in FIG. 1A. [Figure 4] 5A to 5C are cross-sectional views illustrating steps in a method for manufacturing inkjet recording heads in an example and a comparative example. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] Hereinafter, an embodiment of the present invention will be described in detail. The present invention relates to a method for producing a fine pattern using a photosensitive resin composition containing an epoxy resin, a fluorine compound, a photocationic polymerization initiator, and a solvent. The photosensitive resin composition is characterized in that the boiling point or sublimation point of the fluorine compound is 200° C. or higher, the solvent contains an ester solvent, and the ratio of the ester solvent in the total solvent is 5 mass % or higher. Each component of the photosensitive resin composition will be described below.

[0009] <Epoxy resin> Epoxy resins are used as photosensitive resins. The type of epoxy resin is not particularly limited, but an epoxy resin having high resolution of the pattern formed, excellent reactivity and adhesion is preferred. Specifically, it can be appropriately selected from alicyclic epoxy resins, cresol novolac type epoxy resins, bisphenol A type epoxy resins, bisphenol F type epoxy resins, dicyclopentadiene type epoxy resins, and the like. In addition, since a fluorine compound described later having a polar group such as a hydroxyl group can be suitably selected for the purpose of imparting solubility, an alicyclic epoxy resin or a glycidyl type epoxy resin having a higher affinity for the polar group of a fluorine compound can be suitably selected as the epoxy resin. In addition, the epoxy equivalent of the epoxy resin is preferably 2000 or less, more preferably 1000 or less. By having an epoxy equivalent of 2000 or less, the crosslink density does not decrease during the curing reaction, and the glass transition temperature and adhesion of the cured product can be prevented from decreasing. In addition, the epoxy equivalent is a value measured in accordance with JISK-7236. Specific examples of epoxy resins include hydrogenated bis-A type epoxy resins such as hydrogenated bisphenol A diglycidyl ether, and alicyclic epoxies such as epoxy cyclohexane carboxylate and 1,2-epoxy-4-(2-oxiranyl)cyclohexane adduct of 2,2-bis(hydroxymethyl)-1-butanol. Specific examples of commercially available epoxy resins include Denacol EX-252 (manufactured by Nagase Chemtex Corporation) and EHPE-3150 (manufactured by Daicel Chemical Industries, Ltd.).

[0010] <Fluorine compounds> The fluorine compound to be selected is one that exhibits sufficient swelling resistance, does not volatilize due to heat during the manufacturing process, and has high compatibility with the above-mentioned epoxy resin. First, a fluorine compound that is difficult to volatilize is selected that has a boiling point or sublimation point of 200°C or higher. The boiling point or sublimation point of the fluorine compound must be higher than the heating temperature after exposure of the epoxy resin in the fine pattern formation process. In order to promote the curing reaction of the epoxy resin, a main baking temperature of 180 to 200°C is suitable, which balances the progress of curing and the suppression of decomposition of the cured product. From the above points, a fluorine compound having a boiling point or sublimation point of 200°C or higher is used. As a fluorine compound that is difficult to volatilize and has a boiling point or sublimation temperature of 200°C or higher, a compound with a high molecular weight can be mentioned, but since the solubility is significantly reduced, an aromatic ring-containing compound that is a solid at room temperature can be suitably selected. From the viewpoint of compatibility with epoxy resins, those having an ether group or a hydroxyl group, or both, are preferred. Examples of aromatic ring-containing compounds that have an ether group or a hydroxyl group and are solid at room temperature include 2,2-bis(4-hydroxyphenyl)-hexafluoropropane, 2,2-bis[4-(4-aminophenoxy)phenyl]-hexafluoropropane, 2,2-bis(3-amino-4-hydroxyphenyl)-hexafluoropropane, etc. Examples of commercially available specific fluorine compounds include trade names: BIS-AF-A, BIS-AP-AF (manufactured by Central Glass Co., Ltd.), etc. The amount of the fluorine compound added is preferably 5 parts by mass or more and 60 parts by mass or less, more preferably 10 parts by mass or more and 50 parts by mass or less, relative to 100 parts by mass of the epoxy resin. By adding an amount of the fluorine compound of 60 parts by mass or less, the amount of the non-photosensitive fluorine compound is suppressed, and the deterioration of the photopatterning property can be prevented. Furthermore, by adding an amount of 5 parts by mass or more, sufficient swelling resistance can be imparted.

[0011] <Solvent> The solvent is selected so that the photosensitive resin solution becomes a uniform solution and uniform coating properties can be obtained. Therefore, an ester solvent is used as a solvent that easily dissolves organic resins and has good affinity with the polar group of the fluorine compound. In addition, in the heating step during the coating film formation in the first step of the fine pattern method described below, it is necessary to prevent the material from coagulating due to the sudden evaporation of the solvent. Therefore, as the solvent, a solvent having a boiling point equal to or higher than the heating temperature in the first step, for example, a boiling point of 100°C or higher, can be suitably used. Examples of ester solvents having a boiling point of 100°C or higher include propylene glycol monomethyl ether acetate, propylene carbonate, and isobutyl acetate. In addition, two or more types of solvents can be used as the solvent to be used, and it is essential that the ratio of the ester solvent in the total solvent is 5% by mass or more so that the effect of the ester solvent is not impaired. If it is less than 5% by mass, the solubility of the fluorine compound decreases, so that the coating surface of the photosensitive resin solution becomes non-uniform and the fine pattern shape also deteriorates. Furthermore, the content of the solvent (total amount when two or more types are used) is preferably 30 parts by mass or more and 200 parts by mass or less relative to 100 parts by mass of the epoxy resin from the viewpoint of coatability.

[0012] <Photocationic polymerization initiator> The photocationic polymerization initiator is not particularly limited as long as it can cure the epoxy resin, but in order to prevent the fluorine compound from volatilizing in the heating process, a photocationic polymerization initiator capable of low-temperature curing and having a high catalytic function can be suitably used. As a specific photocationic polymerization initiator, an ionic acid generator can be preferably selected. Furthermore, a compound having a structure in which the cation part of the ionic acid generator is an onium type with high absorption and the anion part is a borate type, phosphorus type, or antimony type with high acid strength can be preferably selected. Specific examples of commercially available photoacid generators include trade names: ADEKA Optomer SP-150, SP-151, SP-170, SP-171, and SP-172 (all manufactured by ADEKA Corporation). Furthermore, the content of the photocationic polymerization initiator is preferably 0.5 parts by mass or more and 20 parts by mass or less with respect to 100 parts by mass of the epoxy resin from the viewpoint of resin curing property.

[0013] <Method of manufacturing fine patterns> The method for producing a fine pattern according to the present invention comprises the steps of: A first step of forming a photosensitive resin layer on a substrate; a second step of exposing and developing the photosensitive resin layer to form a fine pattern; The photosensitive resin layer is formed using the photosensitive resin composition. The first step may be carried out, for example, by the following method. A coating method comprising a coating step of coating the photosensitive resin composition according to the present invention on a substrate, and a coating step of heating to remove a certain amount of the solvent to form a photosensitive resin layer. This is the so-called dry film method, in which a layer of a photosensitive resin composition is formed separately and then transferred onto a substrate on which a fine pattern is to be formed. Hereinafter, the method for producing a fine pattern including the first step of a coating method will be specifically described with reference to the drawings. An example of a fine pattern obtained by the method according to the present invention is shown in Fig. 1. The fine pattern 2 shown in Fig. 1 is shown as a rectangular parallelepiped pattern provided at a predetermined interval on a substrate 1, but is not limited thereto and can be applied to any pattern that can be formed by known exposure and development. This fine pattern is composed of a cured product of the photosensitive resin composition according to the present invention. Fig. 2 is a diagram showing an example of an embodiment of a method for producing a fine pattern according to the present invention. Fig. 2(A) to (C) are process cross-sectional views corresponding to the A-A' cross section in Fig. 1. However, the present invention is not limited to this embodiment.

[0014] 2(A), in the first step, the above-mentioned photosensitive resin composition is applied onto a substrate, and heated to volatilize and remove a part of the solvent, etc., to form a photosensitive resin layer 11. The material of the base material is not particularly limited, and known substrates such as insulating substrates such as glass and alumina, resin substrates such as plastic, and metal or semimetal substrates such as Al and Si can be used. The method of applying the photosensitive resin composition is not particularly limited as long as it is a method that can form a uniform film. For example, spin coating or slit coating can be used. Heating after application is preferable from the viewpoint of reactivity with the substrate 1. In this case, in order to prevent the unexposed portion 12 described later from curing, the heating temperature is preferably equal to or lower than the boiling point of the solvent contained in the photosensitive resin composition, particularly 70 to 120°C. The heating time is not particularly limited, but can be, for example, 1 to 10 minutes.

[0015] In the second step, the photosensitive resin layer 11 formed in the first step is exposed to light. For example, as shown in FIG. 2(B), the photosensitive resin layer is exposed to light at a wavelength at which a photocuring reaction proceeds through a photomask 5 on which a pattern is formed on the photosensitive resin layer 11, to form an exposed portion 4, which is a latent image of a fine pattern, and an unexposed portion 12 that is not exposed to light. Next, a post-exposure bake (PEB) is performed. At this time, the catalyst may diffuse into the unexposed portion 12 due to retention after exposure, and it is preferable to perform PEB immediately after exposure in order to improve patterning accuracy. In addition, the PEB temperature needs to proceed with the reaction so that the exposed portion pattern is not removed during the development step, and is preferably adjusted to 70° C. or higher. The heat treatment time is not particularly limited, but can be, for example, 1 to 10 minutes. It is more preferable that the cured state of the photosensitive resin composition before development is such that the reaction rate of the epoxy group of the epoxy resin is 50% or more. The reaction rate of the epoxy group is determined from the ring-opening rate of the epoxy group. The ring-opening rate of the epoxy group indicates the ring-opening rate of the epoxy group in the epoxy resin composition. The ring-opening rate of the epoxy group can be calculated using the peak area derived from the epoxy group based on the absorbance spectrum of the epoxy resin composition obtained by Fourier transform infrared spectroscopy (FT-IR). The "peak area derived from the epoxy group" here refers to the peak area derived from the epoxy group at a wave number of 910 cm. -1 It is the integral value of the epoxy group-derived peak located near the baseline, which is the line connecting the left and right minimums closest to this peak. Specifically, the epoxy group ring-opening rate E (%) is calculated using the following formula, where X is the peak area in the absorbance spectrum before exposure and Y is the peak area in the absorbance spectrum after exposure. E(%) = [(XY) / X] x 100

[0016] Next, the exposed photosensitive resin layer is developed to form a fine pattern 2. For example, as shown in FIG. 2(C), a solvent capable of dissolving the unexposed portion 12 of the photosensitive resin layer 11 is used to remove the unexposed portion 12, thereby forming the fine pattern 2. As the solvent (developer) used for development, a solvent capable of dissolving the uncured epoxy resin is preferable. Specifically, it is preferable to use an ester solvent such as propylene glycol monomethyl ether acetate, a ketone solvent such as methyl ethyl ketone or methyl isobutyl ketone, or an aromatic solvent such as xylene. In addition, in order to promote the curing of the photosensitive resin composition, a post-heating step is performed in which the photosensitive resin composition is baked after development. The post-heating step is preferably performed at a temperature of 140° C. or higher. In this case, in order to suppress cracks due to an increase in the membrane stress, the membrane stress of the cured product obtained by the main baking is preferably 20 MPa or less. Since the increase in membrane stress can occur due to thermal contraction and curing contraction, the heating temperature during the main baking and the amount of the fluorine compound added as an unreacted component have a dominant effect. Therefore, the more the amount of the fluorine compound added, the more the increase in membrane stress can be suppressed, and the main baking can be performed at a high temperature. For example, if the amount of the fluorine compound added is 10 parts by mass or more and 40 parts by mass or less with respect to 100 parts by mass of the epoxy resin, the temperature in the post-heating step in the main baking treatment can be 180° C. or more and 200° C. or less. Here, a method for determining the membrane stress of the cured product will be described. To measure the film stress, a sample is prepared that has been exposed to full surface light rather than patterning light. Immediately after the sample is cured, a laser reflection type warpage measuring device (product name: FLX-2320-S, manufactured by KLA-Tencor) is used to measure the change in warpage before and after film formation, and the calculated internal stress is taken as the film stress of the cured product.

[0017] The fine pattern formed by the method according to the present invention has high resolution and high mechanical strength, and is therefore suitable for fine pattern processing in various cutting-edge device fields, and can be particularly suitably used for forming nozzles of liquid ejection heads such as inkjet heads. For example, the photosensitive resin composition can be used as a member (ejection port forming member) that forms the ejection ports and flow paths of the liquid ejection head shown in FIG.

[0018] Hereinafter, one embodiment of a liquid ejection head to which a fine pattern obtained by the method of the present invention is applied will be described with reference to the drawings. Fig. 3(A) is a schematic perspective view showing a liquid ejection head according to an embodiment of the present invention, and Fig. 1(B) is a schematic cross-sectional view of the liquid ejection head according to an embodiment of the present invention, taken along a plane perpendicular to the substrate and passing through AB in Fig. 3(A). The liquid ejection head shown in Fig. 3 has a substrate 1 on which energy generating elements 6 that generate energy for ejecting liquid are formed at a predetermined pitch. Examples of the energy generating elements 6 include electrothermal conversion elements and piezoelectric elements. The energy generating elements 6 may be provided so as to be in contact with the surface of the substrate 1, or may be provided partially hollow relative to the surface of the substrate 1. A control signal input electrode (not shown) for operating the energy generating elements 6 is connected to the energy generating elements 6. In addition, the substrate 1 is provided with a liquid supply port 7 for supplying liquid such as ink. A silicon substrate made of silicon is an example of the substrate 1. The silicon substrate is preferably made of single crystal silicon, and the crystal orientation of the surface is preferably (100). On the substrate 1, a discharge port forming member 8 having a discharge port 9 is formed, and the discharge port forming member 8 forms a side wall of a flow path 10. In this embodiment, at least this discharge port forming member 8 is formed from a fine pattern made of a cured product of a photosensitive resin composition. In this liquid ejection head, liquid such as ink is supplied from a liquid supply port 7 through a flow path 10, and by applying pressure generated by energy generating elements 6, the liquid is ejected as ink droplets from ejection ports 9 via the flow path 10. EXAMPLES

[0019] The present invention will be described in detail below with reference to examples and comparative examples, but the present invention is not limited to the configurations embodied in these examples. Furthermore, "parts" used in the examples and comparative examples means "parts by mass" unless otherwise specified.

[0020] <Examples 1 to 20 and Comparative Examples 1 to 12> (Preparation of photosensitive resin composition, preparation of fine pattern samples) The fine pattern shown in FIG. 1 was fabricated in the process sequence shown in FIG. First, as a photosensitive resin composition, an epoxy resin, a fluorine compound, a silane agent, a photocationic polymerization initiator, and a solvent were mixed in the composition shown in Table 1 or Table 2, and the mixture was stirred at room temperature for three days to obtain a prepared solution. (Only those solutions that were determined to be homogeneous were subjected to the following sample preparation.) Next, as shown in FIG. 2(A), a photosensitive resin composition was applied to a thickness of 25 μm on the Si substrate 1, and heat-treated at 60° C. for 9 minutes to form a photosensitive resin layer 11. Furthermore, as shown in FIG. 2B, the photosensitive resin layer 11 is exposed to 5000 J / m 2 through a photomask 5 using an i-line exposure stepper (manufactured by Canon Inc.). 2 The pattern shape for checking the shape of the fine pattern was set to be line / space = 20 μm / 20 μm. Then, the substrate was heat-treated at 90° C. for 4 minutes. Finally, as shown in FIG. 2(C), the uncured portion 12 of the photosensitive resin composition was removed by developing it for 3 minutes with a mixture of methyl isobutyl ketone (MIBK) and xylene, and then the resulting product was baked at 200° C. to obtain a fine pattern.

[0021] (Evaluation of fine pattern samples / Method of evaluating film stress) ·Swelling resistance The rate of change in film thickness (pattern height) was determined before the test (after the process in FIG. 2(C)) and after the test (after immersion test in a 5% aqueous solution of 1,2-hexanediol (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) at 60°C for 3 days). The film thickness was measured using a non-contact surface measurement system using optical interference (product name: VertScan2.0, manufactured by Ryoka Systems Co., Ltd.) and evaluated according to the following evaluation criteria. The measurement conditions were as follows: objective lens = 50x, lens barrel = 1.0x Body, zoom lens = No Relay, wavelength filter = white, measurement mode = Wave, field of view size = 640x480. ○: The change in film thickness before and after the test is less than 5%. △: The change in film thickness before and after the test is 5% to 10%. ×: The change in film thickness before and after the test exceeds 10%.

[0022] Mask reproducibility The pattern width in the unexposed area on the substrate was observed using a scanning electron microscope (product name: S-4300, manufactured by Hitachi High-Technologies Corporation). The appearance was evaluated according to the following criteria. A: The line / space pattern has a line width of 20 μm and a linear pattern. Both the top view and cross-sectional shapes reproduce the exposure photomask. △: The line / space pattern width is 18 to 19 μm or 21 to 22 μm, and a linear pattern is obtained. The top surface shape does not reproduce the photomask shape slightly. Or, slight thinning of the pattern is confirmed in the cross-sectional shape. ×: The line / space pattern width is less than 18 μm or more than 22 μm, or the pattern has an overhanging shape. Either the top surface shape or the cross-sectional shape, or both, do not reproduce the exposure photomask.

[0023] -Pattern height accuracy The pattern height was measured using a non-contact surface measurement system using optical interference (product name: VertScan2.0, manufactured by Ryoka Systems Co., Ltd.) The measurement conditions were: objective lens = 50x, lens barrel = 1.0x Body, zoom lens = NoRelay, wavelength filter = white, measurement mode = Wave, field of view size = 640x480. The height accuracy was measured at 30 points on the wafer surface (the same points in all examples and comparative examples), and the distribution was evaluated as 3σ (standard deviation) / average value. ○: 3σ / average value is less than 5%, and high height precision is obtained. △: 3σ / average value is 5% or more and less than 10%, and the height precision is slightly reduced. ×: 3σ / average value is 10% or more, and the height precision is reduced.

[0024] ·Membrane stress A sample was prepared in which the exposure process was fully exposed (others were treated in the same process). Immediately after the sample was cured, a laser reflection type warpage measuring device (product name: FLX-2320-S, manufactured by KLA-Tencor) was used to measure the change in warpage before and after film formation, and the calculated internal stress was taken as the film stress of the cured product.

[0025] (Evaluation of fine pattern samples / membrane stress evaluation results) The results are shown in Tables 1 and 2. For Examples 2 to 6, 8 to 10, 12, 15, and 16, the swelling resistance, mask reproducibility, and pattern height accuracy were also good. In particular, Examples 2 and 3 showed excellent evaluation results. For Comparative Examples 1, 2, and 7 to 11, the mask reproducibility was poor, and for Comparative Examples 3 to 7, the swelling resistance was low. Furthermore, for Comparative Example 12, a uniform preparation solution was not obtained.

[0026] (Fabrication of Ink Jet Recording Head) The ink jet recording head was manufactured in the process sequence shown in FIG. First, as shown in FIG. 4(A), a positive photosensitive resin that will be a mold for the ink flow path was applied by spin coating onto a silicon substrate 1 on which an energy generating element 6 was provided. Polymethyl isopropenyl ketone (product name: ODUR-1010, manufactured by Tokyo Ohka Kogyo Co., Ltd.) was used as the positive photosensitive resin. After application, a heat treatment was performed at 120°C for 6 minutes to form a positive photosensitive resin layer with a thickness of 14 μm. Next, a pattern of the ink flow path was exposed using an exposure device (product name: UX3000, manufactured by Ushio Inc.), and the exposed portion of the positive photosensitive resin layer was developed using MIBK (methyl isobutyl ketone), followed by rinsing with IPA (isopropyl alcohol) to form a mold material 3. 4(B), a photosensitive resin composition was applied onto the mold material 3 and the substrate 1 by spin coating, and heat-treated at 60° C. for 9 minutes to form a 25 μm-thick photosensitive resin layer 11 to serve as a discharge port member. In this example and comparative example, the photosensitive resin layer 11 was a resin layer made of a resin material having the composition shown in Tables 1 and 2 below. Next, as shown in FIG. 4C, a photomask 5 is used to perform lithography with an i-line stepper at 4000 J / m so that the openings in the surface layer of the photosensitive resin layer 11 will have a diameter of about 8.3 μm. 2 The resist was exposed to light for 100 s, and then subjected to PEB treatment at 90° C. for 4 minutes. After that, the photosensitive resin layer 11 after the heat treatment was subjected to a development process to form the discharge port 9 as shown in Fig. 4(D). The development process was performed using a mixture of MIBK and xylene, followed by rinsing with xylene. Furthermore, a main baking process was performed at 140°C for 4 minutes.

[0027] Next, an etching mask (not shown) was formed on the back surface of the substrate 1, and the silicon substrate 1 was anisotropically etched to form the ink supply port 7 as shown in Fig. 4(E) (Fig. 2(e)). At this time, a protective film (OBC manufactured by Tokyo Ohka Kogyo Co., Ltd.) (not shown) was applied onto the photosensitive resin layer 11 in order to protect the ejection port formation surface from the etching solution. Next, the protective film was dissolved and removed with xylene, and then a deep-UV exposure device (product name: UX-3000, manufactured by Ushio Inc.) was used to expose the film through a negative resist at 250,000 mJ / cm. 2 The entire surface was exposed to light at an exposure dose of 100 nm to solubilize the mold material 3. The mold material 3 was then dissolved and removed by immersion in methyl lactate while applying ultrasonic waves, forming a flow path 10 as shown in Fig. 4(F). After that, the mold material was finally baked at 200°C. Next, mounting steps such as joining members for ink supply (not shown), electrical joining (not shown) for driving the energy generating element 1, and sealing (not shown) for protecting the electrical joining parts were performed to complete the inkjet recording head. This inkjet recording head was evaluated by the following method.

[0028] <Inkjet recording head evaluation method> The ink for evaluation was poured into the tank, and the printing characteristics were evaluated. The printing characteristics were evaluated according to the following criteria. ◎: Good impact accuracy of 3μm or less ○: The impact accuracy is within the allowable range of 5 μm or less. ×: Impact accuracy is over 5μm

[0029] (Inkjet recording head evaluation results) The results are shown in Tables 1 and 2. Particularly good printing performance was obtained in Examples 2 to 6, 8 to 10, 12, 15, and 16, and the printing quality was particularly excellent in Examples 2 and 3. On the other hand, the printing quality was reduced in Comparative Examples 1 to 11.

[0030] [Table 1]

[0031] [Table 2]

[0032] The present invention includes the following configurations. [Method 1] A first step of forming a photosensitive resin layer on a substrate; a second step of exposing and developing the photosensitive resin layer to form a fine pattern; A method for producing a fine pattern comprising: the photosensitive resin layer is formed using a photosensitive resin composition containing an epoxy resin, a fluorine compound, a photocationic polymerization initiator, and a solvent; A method for producing a fine pattern, wherein the boiling point or sublimation point of the fluorine compound is 200° C. or higher, the solvent contains an ester solvent, and the ratio of the ester solvent to the total solvent is 5 mass % or higher. [Method 2] The method for producing a fine pattern according to [Method 1], wherein the epoxy resin is an alicyclic epoxy resin or a glycidyl type epoxy resin. [Method 3] The method for producing a fine pattern according to [Method 1] or [Method 2], wherein the fluorine compound is an aromatic ring-containing compound that is solid at room temperature. [Method 4] The method for producing a fine pattern according to any one of [Method 1] to [Method 3], wherein the fluorine compound has an ether group, a hydroxyl group, or both. [Method 5] The method for producing a fine pattern according to any one of [Method 1] to [Method 4], wherein the amount of the fluorine compound added is 5 parts by mass or more and 60 parts by mass or less with respect to 100 parts by mass of the epoxy resin. [Method 6] 3. The method for producing a fine pattern according to claim 1, which is any one of [Method 1] to [Method 5], wherein the amount of the fluorine compound added is 10 parts by mass or more and 50 parts by mass or less relative to 100 parts by mass of the epoxy resin. [Method 7] The method for producing a fine pattern according to any one of [Method 1] to [Method 6], wherein the boiling point of the ester solvent is 100° C. or higher. [Method 8] The method for producing a fine pattern according to any one of [Method 1] to [Method 7], wherein the total content of the solvent contained in the photosensitive resin composition is 30 parts by mass or more and 200 parts by mass or less per 100 parts by mass of the epoxy resin. [Method 9] The method for producing a fine pattern according to any one of [Method 1] to [Method 8], wherein the epoxy equivalent of the epoxy resin is 2000 or less. [Method 10] The method for producing a fine pattern according to any one of [Method 1] to [Method 9], wherein the epoxy equivalent of the epoxy resin is 1,000 or less. [Method 11] The method for producing a fine pattern according to any one of [Method 1] to [Method 10], wherein the photocationic polymerization initiator is an ionic acid generator. [Method 12] The method for producing a fine pattern according to [Method 11], wherein the cationic portion of the ionic acid generator has an onium structure. [Method 13] The method for producing a fine pattern according to [Method 11] or [Method 11], wherein the anion moiety of the ionic acid generator has a borate-based, phosphorus-based, or antimony-based structure. [Method 14] The method for producing a fine pattern according to any one of [Method 1] to [Method 13], wherein the first step includes a step of applying the photosensitive resin composition onto a substrate and a step of heating the composition, and the heating temperature in the heating step is equal to or lower than the boiling point of the solvent. [Method 15] The method for producing a fine pattern according to any one of [Method 1] to [Method 14], wherein the amount of the fluorine compound added is 10 parts by mass or more and 40 parts by mass or less relative to 100 parts by mass of the epoxy resin, and the second step has a post-heating step of performing a main baking treatment, and the heating temperature in the post-heating step is 180° C. or more and 200° C. or less. [Explanation of symbols]

[0033] 1 Board 2. Fine pattern 3 Shape material 4 Exposure area 5. Photomask 6 Energy generating elements 7 Liquid supply port 8. Discharge port forming member 9 Discharge port 10 Flow Path 11 Photosensitive resin layer 12 Unexposed area

Claims

1. The first step is to form a photosensitive resin layer on a substrate, A second step involves exposing and developing the photosensitive resin layer to form a fine pattern. A method for manufacturing a fine pattern including, The photosensitive resin layer is formed using a photosensitive resin composition comprising an epoxy resin, a fluorine compound, a photocationic polymerization initiator, and a solvent. The fluorine compound has a boiling point or sublimation point of 200°C or higher, and the solvent contains an ester solvent, with the proportion of the ester solvent in the total solvent being 5% by mass or higher. A method for producing a fine pattern, wherein the amount of the fluorine compound added is 10 parts by mass or more and 50 parts by mass or less per 100 parts by mass of the epoxy resin.

2. The method for producing a fine pattern according to claim 1, wherein the epoxy resin is an alicyclic epoxy resin or a glycidyl type epoxy resin.

3. The method for producing a fine pattern according to claim 1 or 2, wherein the fluorine compound is an aromatic ring-containing compound that is solid at room temperature.

4. The method for producing a fine pattern according to claim 1 or 2, wherein the fluorine compound has an ether group, a hydroxyl group, or both.

5. The method for producing a fine pattern according to claim 1 or 2, wherein the boiling point of the ester solvent is 100°C or higher.

6. The method for producing a fine pattern according to claim 1 or 2, wherein the total solvent content in the photosensitive resin composition is 30 parts by mass or more and 200 parts by mass or less per 100 parts by mass of epoxy resin.

7. The method for producing a fine pattern according to claim 1 or 2, wherein the epoxy equivalent of the epoxy resin is 2000 or less.

8. The method for producing a fine pattern according to claim 1 or 2, wherein the epoxy equivalent of the epoxy resin is 1000 or less.

9. The method for producing a fine pattern according to claim 1 or 2, wherein the photocationic polymerization initiator is an ionic acid generator.

10. The method for producing a fine pattern according to claim 9, wherein the cation portion of the ionic acid generator has an onium-based structure.

11. The method for producing a fine pattern according to claim 10, wherein the anion portion of the ionic acid generator has a borate-based, phosphorus-based, or antimony-based structure.

12. The method for producing a fine pattern according to claim 1 or 2, wherein the first step includes the steps of applying the photosensitive resin composition onto a substrate and heating it, and the heating temperature in the heating step is below the boiling point of the solvent.

13. The method for producing a fine pattern according to claim 1 or 2, wherein the amount of the fluorine compound added is 10 parts by mass or more and 40 parts by mass or less per 100 parts by mass of the epoxy resin, and the second step includes a post-heating step of the main firing treatment, the heating temperature of the post-heating step is 180°C or more and 200°C or less.

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