Photosensitive element, method for forming resist pattern, and method for manufacturing printed circuit board

Abstract

To provide a photosensitive element capable of reducing the number of defects generated in a resist pattern.SOLUTION: A photosensitive element comprises a support film, a barrier layer, and a photosensitive layer in the stated order, wherein the number of particles having a diameter of at least 0.8 μm as measured on the barrier layer-side surface of the support film is at most 100 per 0.0225 mm2.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] This disclosure relates to a photosensitive element, a method for forming a resist pattern, and a method for manufacturing a printed circuit board. [Background technology]

[0002] Conventionally, in the field of printed circuit board manufacturing, photosensitive elements comprising a photosensitive resin composition and a layer formed on a support film using the photosensitive resin composition (hereinafter also referred to as the "photosensitive layer") have been widely used as resist materials for etching or plating processes.

[0003] Printed circuit boards are manufactured using the above-mentioned photosensitive element by, for example, the following procedure. First, the photosensitive layer of the photosensitive element is laminated onto a circuit-forming substrate such as a copper-clad laminate. At this time, the photosensitive layer is laminated so that the side opposite to the side in contact with the support film is in close contact with the circuit-forming surface of the circuit-forming substrate. Lamination is performed, for example, by heating and pressing the photosensitive layer onto the circuit-forming substrate (atmospheric pressure lamination method).

[0004] Next, radicals are generated by exposing a desired area of ​​the photosensitive layer through a support film using a mask film or the like. The generated radicals travel through several reaction pathways and contribute to the crosslinking reaction (photocuring reaction) of the photopolymerizable compound. Then, after peeling off the support film, the uncured portion of the photosensitive layer is dissolved or dispersed and removed with a developer to form a resist pattern. Next, the resist pattern is used as a resist to form a conductive pattern by etching or plating, and finally the photocured portion (resist pattern) of the photosensitive layer is peeled off (removed).

[0005] Incidentally, in recent years, with the increasing performance of semiconductor packages, there has been a demand for photosensitive elements that enable the formation of finer and higher-yield wiring. However, as mentioned above, when the photosensitive layer is exposed via a support film, minute defects may occur in the resulting resist pattern, which can cause short circuits in the wiring and worsen the yield.

[0006] Defects in the resist pattern occur when light is scattered by particles such as lubricants in the support film. Therefore, a method has been investigated to form a superior resist pattern by peeling off the support film before exposure and then exposing the photosensitive layer. However, when the photosensitive layer is exposed after the support film has been peeled off, the generated radicals come into contact with oxygen in the air, causing the radicals to stabilize (deactivate) rapidly, making it difficult for the photocuring reaction of the photopolymerizable compound to proceed. In addition, if a mask is attached to the photosensitive layer during exposure, problems such as damage to the photosensitive layer or contamination of the mask occur when the mask is peeled off. Therefore, in order to improve the above problems, it has been investigated to use a photosensitive element equipped with a resin protective layer (barrier layer) between the support film and the photosensitive layer (see, for example, Patent Documents 1 and 2). [Prior art documents] [Patent Documents]

[0007] [Patent Document 1] Special Publication No. 2013-505483 [Patent Document 2] Special Publication No. 2013-505484 [Overview of the project] [Problems that the invention aims to solve]

[0008] However, even when using a photosensitive element that includes a barrier layer between the support film and the photosensitive layer, it is not always possible to sufficiently suppress defects in the resulting resist pattern, and there is room for further improvement.

[0009] This disclosure has been made in view of the problems of the prior art described above, and aims to provide a photosensitive element that can reduce the number of defects occurring in a resist pattern, a method for forming a resist pattern, and a method for manufacturing a printed wiring board. [Means for solving the problem]

[0010] The inventors of the present invention conducted intensive research to solve the above problems and found that in a photosensitive element having a barrier layer between the photosensitive layer and the support film, traces of particles such as lubricants contained in the support film adhere to the surface of the barrier layer, and the light exposed is scattered by the unevenness of these particle traces, causing defects in the resist pattern. They then found that these particle traces can be reduced by using a support film that satisfies predetermined conditions, and thus completed the present invention.

[0011] In other words, this disclosure provides the following photosensitive elements, a method for forming resist patterns, and a method for manufacturing printed circuit boards. [1] A photosensitive element comprising a support film, a barrier layer, and a photosensitive layer in this order, wherein the number of particles with a diameter of 0.8 μm or more measured on the surface of the support film on the barrier layer side is 0.0225 mm 2 There are fewer than 100 photosensitive elements per unit. [2] The number of particles with a diameter of 0.8 μm or more measured on the surface of the barrier layer side of the support film is 0.0225 mm 2 A photosensitive element as described in [1] above, wherein there are five or more of them. [3] The photosensitive element according to [1] or [2] above, wherein the coefficient of linear expansion of the support film in the TD direction at 80 to 110°C is 30 ppm / K or more. [4] The photosensitive element according to [3] above, wherein the coefficient of linear expansion of the support film in the TD direction at 80 to 110°C is 170 ppm / K or less. [5] A photosensitive element according to any one of [1] to [4] above, wherein the barrier layer contains a water-soluble resin. [6] The photosensitive element according to any one of [1] to [5] above, wherein the thickness of the barrier layer is 2 to 12 μm. [7] The number of particles having a diameter of 5.0 μm or more measured on the surface of the support film on the barrier layer side is 0 per 0.0225 mm 2 The photosensitive element according to any one of [1] to [6] above. [8] Using the photosensitive element according to any one of [1] to [7] above, on a substrate, a step of arranging a photosensitive layer, a barrier layer, and a support film in this order from the substrate side, removing the support film, and exposing the photosensitive layer through the barrier layer with actinic light, and a step of removing the uncured portion of the photosensitive layer and the barrier layer from the substrate, A method for forming a resist pattern. [9] A method for manufacturing a printed wiring board, comprising a step of forming a conductor pattern by etching or plating a substrate on which a resist pattern is formed by the method for forming a resist pattern according to [8] above.

Advantages of the Invention

[0012] According to the present disclosure, it is possible to provide a photosensitive element, a method for forming a resist pattern, and a method for manufacturing a printed wiring board that can reduce the number of defects generated in the resist pattern.

Brief Description of the Drawings

[0013] [Figure 1] It is a schematic cross-sectional view showing an embodiment of the photosensitive element of the present disclosure. [Figure 2] It is a diagram schematically showing an example of a manufacturing process of a printed wiring board by a semi-additive process.

Modes for Carrying Out the Invention

[0014] Preferred embodiments of this disclosure will be described in detail below, with reference to drawings as necessary. It goes without saying that in the following embodiments, components (including elemental steps, etc.) are not necessarily essential unless specifically indicated or considered fundamentally essential. The same applies to numerical values ​​and ranges, and should not be interpreted as unduly limiting this disclosure.

[0015] In this specification, (meth)acrylic acid means at least one of acrylic acid and its corresponding methacrylic acid. The same applies to other similar expressions such as (meth)acrylate. Unless otherwise specified, the materials exemplified below may be used individually or in combination of two or more. The content of each component in the composition means the total amount of multiple substances present in the composition if multiple substances corresponding to each component are present in the composition, unless otherwise specified.

[0016] Furthermore, in this specification, the term "process" includes not only independent processes, but also processes that cannot be clearly distinguished from other processes, as long as their intended function is achieved.

[0017] Furthermore, in this specification, numerical ranges indicated using "~" represent a range that includes the numbers before and after "~" as the minimum and maximum values, respectively. Also, in numerical ranges described in stages in this specification, the upper or lower limit of one stage of the numerical range may be replaced with the upper or lower limit of another stage of the numerical range. Also, in numerical ranges described in this specification, the upper or lower limit of that numerical range may be replaced with the values ​​shown in the examples. Furthermore, in this specification, the term "layer" includes not only structures that are formed on the entire surface when observed in a plan view, but also structures that are formed on only a part of it.

[0018] [Photosensitive element] As shown in Figure 1, the photosensitive element 1 of this embodiment comprises a support film 2, a barrier layer 3, and a photosensitive layer 4 in that order, and may further include other layers such as a protective layer 5. Furthermore, the number of particles with a diameter of 0.8 μm or larger measured on the surface F1 of the support film 2 on the barrier layer 3 side is 0.0225 mm 2 There are 100 or fewer per layer. The following describes each layer of the photosensitive element according to this embodiment in detail.

[0019] <Support film> Examples of the support film in this embodiment include polyester films such as polyethylene terephthalate (PET), polybutylene terephthalate (PBT), and polyethylene-2,6-naphthalate (PEN), as well as polyolefin films such as polypropylene and polyethylene. Among these, polyester films may be used. Using a polyester film as the support film tends to improve the mechanical strength and heat resistance of the support film. Furthermore, using a polyester film tends to suppress defects such as wrinkles in the barrier layer that occur when forming the barrier layer on the support film, thereby improving workability. In addition, from the viewpoint of improving slipperiness and windability, a polyester film containing particles (lubricants, etc.) may be used. When using a polyester film containing particles (lubricants, etc.), the barrier layer may be formed on the side having the particles (lubricants, etc.). Examples of such polyester films include a polyester film with particles (lubricants, etc.) kneaded into it, a polyester film with layers containing particles (lubricants, etc.) on both sides, or a polyester film with a layer containing particles (lubricants, etc.) on one side. The support film may be single-layer or multi-layer.

[0020] Methods for adding particles such as lubricants to a support film include, for example, kneading particles (such as lubricants) into the support film, and forming a layer containing particles (such as lubricants) on top of the support film using known methods such as roll coating, flow coating, spray coating, curtain flow coating, dip coating, and slit die coating.

[0021] The support film has a minimum number of particles (such as lubricants) with a diameter of 0.8 μm or larger, measured on the surface F1 where the barrier layer is formed, which is 0.0225 mm. 2 The number of particles is 100 or less per unit area. By using a support film that satisfies the above conditions, it is possible to suppress the adhesion of traces of particles contained in the support film to the surface of the barrier layer, thereby reducing the number of defects that occur in the resist pattern. Furthermore, by using a support film that satisfies the above conditions, the LER (Line Edge Roughness) of the resist pattern can be reduced. The number of particles may be 85 or less, 70 or less, 50 or less, 30 or less, or 20 or less, from the viewpoint of further reducing the number of defects that occur in the resist pattern and further reducing LER. The lower limit of the number of particles is not particularly limited and may be 0, 5 or more, or 10 or more. A support film that satisfies the above particle number conditions can be obtained by adjusting the particle size and amount of particles (lubricant, etc.) contained in the support film, or by making the support film a multilayer structure and adjusting the presence or absence of particles in each layer, the particle size and content, and the thickness of each layer, etc. The number of particles (lubricant, etc.) with a diameter of less than 0.8 μm measured on the surface F1 of the support film is not particularly limited.

[0022] The 0.0225 mm of particles (lubricants, etc.) with a diameter of 0.8 μm or more, measured on the surface F1 on the side where the barrier layer is formed. 2 The number of particles per unit can be measured, for example, using a laser microscope under the following conditions. Note that the measuring device is not limited to those listed below.

[0023] -Measurement conditions- Equipment: Hybrid laser microscope (manufactured by Lasertec Corporation, product name: OPTELICS HYBRID) Measurement range: 150 μm square Content of measurement: Obtain the luminance image of the surface F1 of the support film. Binarize the obtained luminance image to measure the particle (lubricant) size and number. Calculate the number within the measurement range of a 150-μm square (0.0225 mm 2 ) of particles with a diameter of 0.8 μm or more.

[0024] For the support film, the number of particles (such as lubricants) with a diameter of 0.8 μm or more per 0.0225 mm 2 may be different between the surface F1 on the side where the barrier layer is formed and the surface opposite to the surface F1. The number of particles (such as lubricants) with a diameter of 0.8 μm or more per 0.0225 mm 2 measured on the surface opposite to the surface F1 may be more than 100. Thereby, while obtaining the effect of the present disclosure of reducing the number of defects generated in the resist pattern, the slipperiness and winding property of the support film can be further enhanced.

[0025] For the support film, the number of particles (such as lubricants) with a diameter of 5.0 μm or more measured on the surface F1 on the side where the barrier layer is formed may be 0 per 0.0225 mm 2 . By using a support film in which the number of particles measured on the surface F1 is 100 or less particles with a diameter of 0.8 μm or more per 0.0225 mm 2 and 0 particles with a diameter of 5.0 μm or more, the trace of the particles contained in the support film adhering to the barrier layer surface can be further suppressed, and the number of defects generated in the resist pattern can be further reduced. Also, by using a support film that satisfies the above conditions, the LER (Line Edge Roughness) of the resist pattern can be further reduced. The support film may not contain (not be observed) particles (such as lubricants) with a diameter of 5.0 μm or more on the surface F1, and may not contain particles (such as lubricants) with a diameter of 5.0 μm or more in the entire support film. The number of particles with a diameter of 5.0 μm or more can be measured in the same manner as the number of particles with a diameter of 0.8 μm or more.

[0026] The haze of the support film may be 0.01-5.0%, 0.01-1.5%, 0.01-1.0%, or 0.01-0.5%. The haze of the support film may also be less than 0.5%. A haze of 0.01% or more tends to make it easier to manufacture the support film itself, and a haze of 5.0% or less tends to make it easier to detect foreign matter in the photosensitive layer when forming the photosensitive layer of the photosensitive element. Here, "haze" means the degree of cloudiness. In this disclosure, the haze refers to the value measured using a commercially available cloudiness meter (turbidimeter) in accordance with the method specified in JIS K7105. Haze can be measured with a commercially available turbidimeter such as the NDH-5000 (manufactured by Nippon Denshoku Industries Co., Ltd., product name).

[0027] The support film may have a coefficient of linear expansion (CTE) in the transverse direction (TD) at 80-110°C of 30 ppm / K or more, 40 ppm / K or more, or 45 ppm / K or more, and may also have a coefficient of linear expansion of 170 ppm / K or less, 150 ppm / K or less, or 125 ppm / K or less. When the coefficient of linear expansion is 30 ppm / K or more, the support film and the photosensitive layer deform sufficiently when the photosensitive layer is laminated onto the substrate together with the support film, and the formation of voids between the photosensitive layer and the substrate can be suppressed. These voids cause defects in the resist pattern after exposure of the photosensitive layer. Therefore, by suppressing the occurrence of these voids, the number of defects in the resist pattern can be further reduced. On the other hand, when the coefficient of linear expansion is 170 ppm / K or less, wrinkles that occur during lamination can be suppressed. The coefficient of linear expansion of the support film in the TD direction at 80-100°C can be measured using a thermomechanical analyzer, for example, by the method shown in the examples.

[0028] The thickness of the support film may be 1-200 μm, 1-100 μm, 1-60 μm, 5-60 μm, 10-60 μm, 10-50 μm, 10-40 μm, 10-30 μm, or 10-25 μm. A support film thickness of 1 μm or more tends to suppress tearing of the support film when it is peeled off. Also, a support film thickness of 200 μm or less tends to yield greater economic benefits.

[0029] <Barrier layer> The photosensitive element of this embodiment includes a barrier layer between the support film and the photosensitive layer. The barrier layer has an oxygen permeability of 6000 mL / m² under conditions of 20°C and 65% RH. 2 The pressure may be less than or equal to day·MPa (calculated for a film thickness of 25 μm). The barrier layer may be a layer formed using a barrier layer-forming resin composition. The barrier layer-forming resin composition of this embodiment may contain a water-soluble resin. The barrier layer may be water-soluble and may be soluble in a developer. Furthermore, from the viewpoint of further improving the gas barrier properties of the barrier layer, the adhesive force between the support film and the barrier layer may be less than the adhesive force between the barrier layer and the photosensitive layer. In this case, when peeling the support film from the photosensitive element, unintended peeling of the barrier layer and the photosensitive layer can be suppressed.

[0030] (Water-soluble resin) The barrier layer may contain a water-soluble resin. Here, "water-soluble resin" refers to a resin with a solubility of 5 g / 100 mL-C6H in 100 mL of hexane at 25°C. 14The following refers to the resin. This solubility can be calculated by mixing hexane at 25°C with the dried water-soluble resin and checking for turbidity. Specifically, prepare two samples: Sample 1, obtained by adding a mixture of dried water-soluble resin A (g) and 100 mL of hexane to a colorless, transparent glass container with a ground-glass stopper; and Sample 2, obtained by adding only 100 mL of hexane. Next, thoroughly shake the samples in the glass containers and confirm that the bubbles have disappeared. Immediately after confirmation, place both containers side by side under diffuse daylight or equivalent light and compare the state of the liquid in Sample 1 and the state of the liquid in Sample 2. Compare Sample 1 and Sample 2, and the amount A (g) added when Sample 1 begins to become more cloudy or when the floating of solids begins to be observed is defined as the solubility of the water-soluble resin in 100 mL of hexane at 25°C.

[0031] Examples of water-soluble resins include polyvinyl alcohol, polyvinylpyrrolidone, and water-soluble polyimides. From the viewpoint of further improving the gas barrier properties of the barrier layer and further suppressing the deactivation of radicals generated by the active light used in exposure, the water-soluble resin may include polyvinyl alcohol. Polyvinyl alcohol can be obtained, for example, by saponifying polyvinyl acetate obtained by polymerizing vinyl acetate. The degree of saponification of the polyvinyl alcohol used in this embodiment may be 50 mol% or more, 70 mol% or more, or 80 mol% or more. The upper limit of such a degree of saponification is 100 mol%. Including polyvinyl alcohol with a degree of saponification of 50 mol% or more tends to further improve the gas barrier properties of the barrier layer and further improve the resolution of the formed resist pattern. In this specification, "degree of saponification" refers to the value measured in accordance with JIS K 6726 (1994) (Test method for polyvinyl alcohol) as specified in the Japanese Industrial Standards.

[0032] The above polyvinyl alcohol may be of two or more different types, such as those with varying degrees of saponification, viscosity, degree of polymerization, and modified species, and may be used in combination. The average degree of polymerization of the polyvinyl alcohol may be 300-5000, 300-3500, or 300-2000. Furthermore, the above water-soluble resin may be used alone or in combination of two or more types. The water-soluble resin may, for example, contain polyvinyl alcohol and polyvinylpyrrolidone. In this case, the mass ratio of polyvinyl alcohol to polyvinylpyrrolidone (PVA:PVP) may be 40:60-90:10, 50:50-90:10, or 60:40-90:10.

[0033] The water-soluble resin content in the barrier layer forming resin composition of this embodiment may be 50 to 300 parts by mass, 60 to 250 parts by mass, 70 to 200 parts by mass, 80 to 150 parts by mass, or 80 to 125 parts by mass per 500 parts by mass of water, from the viewpoint of improving gas barrier properties.

[0034] The water-soluble resin content in the barrier layer may be 99.0-99.95% by mass, 99.3-99.9% by mass, or 99.5-99.8% by mass, based on the total solid content of the barrier layer, from the viewpoint of improving gas barrier properties, improving peelability between the support film and the barrier layer, and improving solubility in the developer.

[0035] (Leveling agent) The barrier layer may contain a leveling agent. The leveling agent is oriented on the surface of the coating film and equalizes the tension of the coating film surface. Examples of leveling agents include acrylic polymers, vinyl polymers, silicone polymers, and fluorine polymers. From the viewpoint of transferability to photosensitive elements and solubility in developing solutions, the leveling agent is preferably an acrylic polymer. The acrylic polymer preferably contains a copolymer having structural units selected from the group consisting of butyl (meth)acrylate, isobutyl (meth)acrylate, and terminal methoxy group EO-modified (meth)acrylate, from the viewpoint of maintaining an appropriate level of adhesion between the barrier layer and the support film, making the adhesive force between the support film and the barrier layer less than the adhesive force between the barrier layer and the photosensitive layer, while suppressing unintended peeling between each layer, and from the viewpoint of easily suppressing the occurrence of defects on the surface of the barrier layer when forming the barrier layer on the support film (making it less likely to repel). It is more preferably a copolymer having structural units derived from butyl (meth)acrylate and isobutyl (meth)acrylate, and even more preferably a copolymer having structural units derived from butyl (meth)acrylate, isobutyl (meth)acrylate, and terminal methoxy group EO-modified (meth)acrylate.

[0036] The content of each structural unit constituting the acrylic polymer may be in the following ranges, for example, based on the total amount of structural units: The content of structural units derived from butyl (meth)acrylate may be 2-20% by mass, 5-15% by mass, or 5-10% by mass, from the viewpoint of further reducing the number of defects on the surface of the barrier layer and further suppressing the damage of the barrier layer when the support film is peeled off. The content of structural units derived from isobutyl (meth)acrylate may be 40-80% by mass, 50-70% by mass, or 55-65% by mass, from the viewpoint of further reducing the number of defects on the surface of the barrier layer and further suppressing the damage of the barrier layer when the support film is peeled off. The content of structural units derived from terminal methoxy group EO-modified (meth)acrylate may be 15-45% by mass, 20-40% by mass, or 25-35% by mass, from the viewpoint of further reducing the number of defects on the surface of the barrier layer and further suppressing the damage of the barrier layer when the support film is peeled off. Furthermore, the weight-average molecular weight of the acrylic polymer may be 10,000 to 40,000 or 10,000 to 20,000, from the viewpoint of further reducing the number of defects on the surface of the barrier layer and further suppressing the damage of the barrier layer when the support film is peeled off.

[0037] The leveling agent content in the barrier layer may be 0.05 to 1.0% by mass, 0.1 to 0.7% by mass, or 0.2 to 0.5% by mass, based on the total solid content of the barrier layer, from the viewpoint of further reducing the number of defects on the surface of the barrier layer and further suppressing the damage of the barrier layer when the support film is peeled off.

[0038] (UV absorber) The barrier layer may contain an ultraviolet absorber. The ultraviolet absorber (UV absorber) is a compound having a light absorption band in the wavelength range of 300 nm to 400 nm. The ultraviolet absorber may be water-soluble. From the viewpoint of further improving resolution, the ultraviolet absorber may have a maximum absorption wavelength in the wavelength range of 250 nm to 500 nm. By including these ultraviolet absorbers, the resolution can be improved.

[0039] The i-ray absorptivity of the UV absorber may be 5-95%, 10-90%, or 15-75%. The i-ray absorptivity can be measured by a UV-Vis spectrophotometer.

[0040] The above-mentioned UV absorbers may be used individually or in combination of two or more types. Furthermore, the solubility of the UV absorber in water at 20°C may be 0.01 g / 100 mL-H2O or higher, 0.1 g / 100 mL-H2O or higher, or 1 g / 100 mL-H2O or higher, from the viewpoint of suppressing aggregation and precipitation of the UV absorber in the barrier layer.

[0041] Examples of UV absorbers include oxybenzophenone compounds, triazole compounds, benzotriazole compounds, salicylic acid ester compounds, benzophenone compounds, diphenyl acrylate compounds, cyanoacrylate compounds, diphenylcyanoacrylate compounds, and iron or nickel complex salt compounds. Among these, oxybenzophenone compounds and benzophenone compounds are preferred from the viewpoint of further improving resolution, benzophenone sulfonic acid compounds are more preferred, and oxybenzophenone sulfonic acid compounds are even more preferred. A "benzophenone sulfonic acid compound" is a compound having a sulfo group in a benzophenone compound, and the benzophenone sulfonic acid compound may be a hydrate. It is hypothesized that these compounds, by having a hydrophilic sulfo group in the benzophenone skeleton, allow the benzophenone skeleton to have a high affinity for the resist, while the sulfo group has a high affinity for the barrier layer, thereby achieving both high resolution and barrier layer removalability. Furthermore, among oxybenzophenone compounds, 2-hydroxy-4-methoxybenzophenone-5-sulfonic acid hydrate, represented by the following formula (1), is preferred.

[0042] [ka]

[0043] The barrier layer of this embodiment may have an absorbance of 0.01 to 2.0 or 0.1 to 1.0 for light at a wavelength of 365 nm. An absorbance of 0.01 or higher tends to yield better resolution, while an absorbance of 2.0 or lower tends to result in a better resist pattern shape. The absorbance of the barrier layer can be measured, for example, using a UV spectrophotometer (Hitachi, Ltd., Spectrophotometer U-3310). The measurement is performed by placing a laminated film with a barrier layer of arbitrary thickness formed on a support film on the measurement side, placing the support film on the reference side, and continuously measuring wavelengths from 300 to 700 nm in absorbance mode, and reading the value at a wavelength of 365 nm.

[0044] (Other ingredients) The barrier layer forming resin composition of this embodiment may contain alcohols having 3 or more carbon atoms. The alcohols having 3 or more carbon atoms may be monohydric alcohols or polyhydric alcohols (excluding the polyhydric alcohol compound plasticizer described later). The alcohols having 3 or more carbon atoms may contain at least one selected from the group consisting of compounds represented by the following chemical formulas (2) to (4) and compounds represented by the following general formula (5). By including these alcohols having 3 or more carbon atoms, the peelability between the barrier layer and the support film can be improved. Therefore, when peeling the support film from the photosensitive element, unintended peeling between the barrier layer and the photosensitive layer can be suppressed, and the decrease in gas barrier properties and the decrease in resolution caused by such unintended peeling can be suppressed. [ka] [ka] [ka] [ka]

[0045] In general formula (5), R 11 R represents an alkyl group, 12 R indicates an alkylene group. 11 The base and R 12 The sum of the number of carbon atoms in the group is 3 or more. Also, R 11 The base and R 12 The sum of the number of carbon atoms with the group may be 10 or less, 8 or less, 7 or less, or 5 or less, from the viewpoint of further improving affinity with water. 11 The alkyl group represented by may be an alkyl group having 1 to 4 carbon atoms, R 12 The alkylene group represented by may be an alkylene group having 1 to 3 carbon atoms. Also, the alcohols with 3 or more carbon atoms represented by general formula (5) may be 2-butoxyethanol or 1-methoxy-2-propanol.

[0046] The above-mentioned alcohols having 3 or more carbon atoms may be used individually or in combination of two or more. Furthermore, the solubility of the alcohols having 3 or more carbon atoms in water at 20°C may be 300 mL / 100 mL-H2O or higher, 500 mL / 100 mL-H2O or higher, or 1000 mL / 100 mL-H2O or higher, from the viewpoint of further suppressing the separation of layers in the barrier layer.

[0047] In this specification, "solubility of alcohols with 3 or more carbon atoms in water at 20°C" can be calculated by mixing the alcohols with water at 20°C and checking for turbidity. Specifically, sample 3 is prepared by placing a mixture of A mL of the alcohols and 100 mL of water in a colorless, transparent glass container with a ground-glass stopper, and sample 4 is prepared by placing only water (100 mL) in the same container. Next, samples 3 and 4 in the glass containers are shaken thoroughly, and it is confirmed that the bubbles have disappeared. Immediately after confirmation, the two containers are placed side by side under diffuse daylight or equivalent light, and the state of the liquid in sample 3 and the state of the liquid in sample 4 are compared. The amount of alcohols added A mL when sample 3 appears cloudier is taken as the solubility of the alcohols in water at 20°C.

[0048] The content of alcohols having 3 or more carbon atoms in the barrier layer forming resin composition of this embodiment may be 100 to 500 parts by mass, or 125 to 450 parts by mass, per 500 parts by mass of water. When the content is 100 parts by mass or more, the peelability between the formed barrier layer and the support film tends to improve, and when it is 500 parts by mass or less, the solubility of the water-soluble resin improves, and the barrier layer tends to form more easily.

[0049] The content of alcohols having 3 or more carbon atoms in the barrier layer of this embodiment may be greater than 0% by mass and 2.0% by mass or less, 0.001 to 2.0% by mass, or 0.005 to 1.0% by mass, based on the total amount of the barrier layer (total amount of solids in the barrier layer forming resin composition that forms the barrier layer). When the content is 2.0% by mass or less, the diffusion of alcohols in subsequent processes tends to be suppressed, and when it is 0.001% by mass or more, the peelability between the barrier layer and the support film tends to be improved.

[0050] The barrier layer forming resin composition of this embodiment may contain alcohols having fewer than 3 carbon atoms. When alcohols having fewer than 3 carbon atoms are included, the content may be 125 to 375 parts by mass, or 150 to 325 parts by mass, per 500 parts by mass of water. When the content is 125 parts by mass or more, the solubility of the water-soluble resin tends to improve, making it easier to form a barrier layer, and when it is 375 parts by mass or less, the peelability between the formed barrier layer and the support film tends to improve. Furthermore, from the viewpoint of improving the peelability between the barrier layer and the support film, the content of alcohols having fewer than 3 carbon atoms in the barrier layer may be 0.1 to 10% by mass (i.e., 0.1 to 10 parts by mass of alcohols having fewer than 3 carbon atoms per 100 parts by mass of alcohols having 3 or more carbon atoms) based on the total amount of alcohols having 3 or more carbon atoms in the barrier layer.

[0051] Furthermore, the barrier layer and the resin composition for forming the barrier layer of this embodiment may contain known additives such as plasticizers and surfactants, to the extent that they do not impede the effects of the present disclosure. They may also contain peel-off accelerators, to the extent that they do not impede the effects of the present disclosure.

[0052] The barrier layer in the photosensitive element of this embodiment can be formed, for example, by applying the barrier layer-forming resin composition of this embodiment onto a support film and drying it. When the barrier layer-forming resin composition contains a leveling agent, applying it onto a support film tends to cause the leveling agent to become unevenly distributed on the surface side of the support film within the coating. This tends to lower the surface tension of the barrier layer-forming resin composition, making it easier to suppress repelling. Furthermore, the uneven distribution of the leveling agent on the surface side of the support film within the barrier layer tends to reduce the adhesion between the support film and the barrier layer.

[0053] The thickness of the barrier layer is not particularly limited. From the viewpoint of ease of removal of the barrier layer, the thickness of the barrier layer may be 12 μm or less, 10 μm or less, 8 μm or less, 7 μm or less, or 6 μm or less. Also, from the viewpoint of ease of formation and resolution of the barrier layer, the thickness of the barrier layer may be 1.0 μm or more, 1.5 μm or more, 2 μm or more, 3 μm or more, or 4 μm or more. Furthermore, from the viewpoint of suppressing the migration of the barrier layer, the thickness of the barrier layer may be 2 μm or more, 3 μm or more, or 4 μm or more.

[0054] <Photosensitive layer> The photosensitive layer in this embodiment is a layer formed using a photosensitive resin composition described later. The photosensitive resin composition can be used for any desired purpose as long as its properties change when exposed to light (for example, it hardens with light), and it may be a negative or positive type. The photosensitive resin composition may contain (A) a binder polymer, (B) a photopolymerizable compound, and (C) a photopolymerization initiator. It may also contain (D) a photosensitizer, (E) a polymerization inhibitor, or other components as needed. The components used in the photosensitive resin composition in this embodiment will be described in more detail below.

[0055] ((A) Binder polymer) (A) The binder polymer (hereinafter also referred to as "component (A)") can be produced, for example, by radical polymerization of a polymerizable monomer. Examples of the polymerizable monomer include polymerizable styrene derivatives substituted at the α-position or aromatic ring, such as styrene, vinyltoluene, and α-methylstyrene; acrylamides such as diacetone acrylamide; ethers of vinyl alcohols such as acrylonitrile and vinyl-n-butyl ether; alkyl (meth)acrylates, benzyl (meth)acrylates such as benzyl methacrylate; tetrahydrofurfuryl (meth)acrylate; dimethylaminoethyl (meth)acrylate; and diethylaminoethyl (meth)acrylate. Examples include sterol, glycidyl (meth)acrylate, 2,2,2-trifluoroethyl (meth)acrylate, 2,2,3,3-tetrafluoropropyl (meth)acrylate, (meth)acrylic acid, α-bromoacrylic acid, α-chloroacrylic acid, β-furyl (meth)acrylic acid, β-styryl (meth)acrylic acid, maleic acid, maleic acid anhydride, monomethyl maleic acid, monoethyl maleic acid, monoisopropyl maleic acid and other maleic acid monoesters, fumaric acid, cinnamic acid, α-cyanocinnamic acid, itaconic acid, crotonic acid, and propiolic acid. These can be used individually or in combination of two or more.

[0056] Among these, alkyl (meth)acrylates may be included from the viewpoint of improving plasticity. Examples of alkyl (meth)acrylates include compounds represented by the following general formula (II), and compounds in which the alkyl group of these compounds is substituted with a hydroxyl group, epoxy group, halogen group, etc. H2C=C(R 6 )-COOR 7 (II)

[0057] In general formula (II), R 6 R represents a hydrogen atom or a methyl group. 7R represents an alkyl group with 1 to 12 carbon atoms. 7 Examples of C1-C12 alkyl groups represented by include methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl, undecyl, dodecyl, and structural isomers of these groups.

[0058] Examples of alkyl (meth)acrylate esters represented by the above general formula (II) include methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, butyl (meth)acrylate, pentyl (meth)acrylate, hexyl (meth)acrylate, heptyl (meth)acrylate, octyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, nonyl (meth)acrylate, decyl (meth)acrylate, undecyl (meth)acrylate, and dodecyl (meth)acrylate. These can be used individually or in combination of two or more.

[0059] Furthermore, component (A) may contain a carboxyl group from the viewpoint of alkali developability. Component (A) containing a carboxyl group can be produced, for example, by radical polymerization of a polymerizable monomer having a carboxyl group with another polymerizable monomer. The polymerizable monomer having a carboxyl group may be (meth)acrylic acid or methacrylic acid. The acid value of component (A) containing a carboxyl group may be 50-250 mgKOH / g, 50-200 mgKOH / g, or 100-200 mgKOH / g.

[0060] The carboxyl group content of component (A) (the ratio of polymerizable monomers having carboxyl groups to the total amount of polymerizable monomers used in the binder polymer) may be 12-50% by mass, 12-40% by mass, 15-35% by mass, 15-30% by mass, or 20-30% by mass, from the viewpoint of improving alkali developability and alkali resistance in a balanced manner. When the carboxyl group content is 12% by mass or more, alkali developability tends to improve, and when it is 50% by mass or less, alkali resistance tends to be excellent.

[0061] Furthermore, the content of structural units derived from polymerizable monomers having carboxyl groups in component (A) correlates with the blending ratio of the polymerizable monomers having carboxyl groups, and may be 12-50% by mass, 12-40% by mass, 15-35% by mass, 15-30% by mass, or 20-30% by mass.

[0062] Furthermore, for component (A), styrene or a styrene derivative may be used as a polymerizable monomer from the viewpoint of adhesion and chemical resistance. When styrene or a styrene derivative is used as a polymerizable monomer, its content (the ratio of styrene or a styrene derivative to the total amount of polymerizable monomer used in component (A)) may be 10-60% by mass, 15-50% by mass, 30-50% by mass, 35-50% by mass, or 40-50% by mass from the viewpoint of further improving adhesion and chemical resistance. When the content is 10% by mass or more, adhesion tends to improve, and when it is 60% by mass or less, the size of the peeling fragments during development can be suppressed, and the time required for peeling tends to be reduced.

[0063] Furthermore, the content of structural units derived from styrene or styrene derivatives in component (A) correlates with the blending ratio of the styrene or styrene derivative, and may be 10-60% by mass, 15-50% by mass, 30-50% by mass, 35-50% by mass, or 40-50% by mass.

[0064] Furthermore, from the viewpoint of resolution and aspect ratio, component (A) may use benzyl (meth)acrylate as a polymerizable monomer. The content of structural units derived from benzyl (meth)acrylate in component (A) may be 15-50% by mass, 15-45% by mass, 15-40% by mass, 15-35% by mass, or 20-30% by mass, from the viewpoint of further improving resolution and aspect ratio.

[0065] These binder polymers can be used individually or in combination of two or more. When two or more are used in combination, examples of component (A) include two or more binder polymers consisting of different polymerizable monomers, two or more binder polymers with different weight-average molecular weights, and two or more binder polymers with different degrees of dispersion.

[0066] (A) Component can be produced by conventional methods. Specifically, for example, it can be produced by radical polymerization of an alkyl (meth)acrylate, (meth)acrylic acid, and styrene, etc.

[0067] The weight-average molecular weight of component (A) may be 20,000 to 300,000, 40,000 to 150,000, 40,000 to 120,000, or 50,000 to 80,000, from the viewpoint of improving mechanical strength and alkali developability in a balanced manner. When the weight-average molecular weight of component (A) is 20,000 or higher, it tends to have excellent developer resistance, and when it is 300,000 or lower, it tends to suppress the lengthening of the development time. The weight-average molecular weight in this specification is measured by gel permeation chromatography (GPC) and converted using a calibration curve created using standard polystyrene.

[0068] The content of component (A) may be 30 to 80 parts by mass, 40 to 75 parts by mass, 50 to 70 parts by mass, or 50 to 60 parts by mass, based on 100 parts by mass of the total solid content of component (A) and component (B) described later. When the content of component (A) is within this range, the coating properties of the photosensitive resin composition and the strength of the photocured part are improved.

[0069] ((B) Photopolymerizable compound) The photosensitive resin composition according to this embodiment may also contain (B) a photopolymerizable compound (hereinafter also referred to as "component (B)"). Component (B) can be used without particular limitations as long as it is a photopolymerizable compound and a photocrosslinkable compound, but for example, a compound having at least one ethylenically unsaturated bond in its molecule can be used.

[0070] (B) Component may contain a bisphenol-type (meth)acrylate compound. Examples of bisphenol-type (meth)acrylate compounds include 2,2-bis(4-((meth)acryloxypolyethoxy)phenyl)propane, 2,2-bis(4-((meth)acryloxypolypropoxy)phenyl)propane, and 2,2-bis(4-((meth)acryloxypolyethoxypolypropoxy)phenyl)propane. These can be used individually or in combination of two or more. In addition, 2,2-bis(4-(methacryloxypentaethoxy)phenyl)propane and 2,2-bis(4-(methacryloxydiethoxy)phenyl)propane may be included as bisphenol-type (meth)acrylate compounds.

[0071] Examples of commercially available bisphenol-type (meth)acrylate compounds include 2,2-bis(4-(methacryloxydiethoxy)phenyl)propane (BPE-200, manufactured by Shin-Nakamura Chemical Industry Co., Ltd.), 2,2-bis(4-(methacryloxypentaethoxy)phenyl)propane (BPE-500, manufactured by Shin-Nakamura Chemical Industry Co., Ltd., or FA-321M, manufactured by Showa Denko Materials K.K.), 2,2-bis(4-(methacryloxypentadecaethoxy)phenyl)propane (BPE-1300, manufactured by Shin-Nakamura Chemical Industry Co., Ltd.), and 2,2-bis(4-(methacryloxypolyethoxy)phenyl)propane (BP-2EM, manufactured by Kyoeisha Chemical Co., Ltd. (EO group: 2.6 (average value))).

[0072] The content of the bisphenol-type (meth)acrylate compound may be 1 to 50% by mass, 3 to 40% by mass, 10 to 40% by mass, 20 to 40% by mass, or 30 to 40% by mass, relative to the total solid content of component (A) and component (B), from the viewpoint of further improving chemical resistance.

[0073] Furthermore, the content of the bisphenol-type (meth)acrylate compound may be 30-99% by mass, 50-97% by mass, 60-95% by mass, 70-95% by mass, or 80-90% by mass, relative to the total solid content of component (B), from the viewpoint of further improving chemical resistance.

[0074] The content of component (B) may be 20 to 70 parts by mass, 25 to 60 parts by mass, or 30 to 50 parts by mass per 100 parts by mass of the total solid content of components (A) and (B). When the content of component (B) is within this range, the resolution, adhesion, and suppression of resist streaking of the photosensitive resin composition are improved, as are the photosensitivity and coating properties.

[0075] ((C) Photopolymerization initiator) The photosensitive resin composition according to this embodiment may contain at least one (C) photopolymerization initiator (hereinafter also referred to as "component (C)"). Component (C) is not particularly limited as long as it can polymerize component (B), and can be appropriately selected from commonly used photopolymerization initiators.

[0076] Examples of component (C) 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 alkylanthraquinones, benzoin ether compounds such as benzoin alkyl ethers, benzoin compounds such as benzoin and alkylbenzoin, benzyl derivatives such as benzyldimethylketal, 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-(9,9'-acridinyl)heptane. These can be used individually or in combination of two or more.

[0077] Among these, a 2,4,5-triarylimidazole dimer may be included from the viewpoint of improving resolution. Examples of the above 2,4,5-triarylimidazole dimer include 2-(o-chlorophenyl)-4,5-diphenylimidazole dimer, 2-(o-chlorophenyl)-4,5-bis-(m-methoxyphenyl)imidazole dimer, and 2-(p-methoxyphenyl)-4,5-diphenylimidazole dimer. Among these, a 2-(o-chlorophenyl)-4,5-diphenylimidazole dimer may be included from the viewpoint of improving photosensitivity stability.

[0078] As an example of a 2,4,5-triarylimidazole dimer, 2,2'-bis(2-chlorophenyl)-4,4',5,5'-tetraphenylbiimidazole is commercially available as B-CIM (manufactured by Hodogaya Chemical Co., Ltd., product name).

[0079] Component (C) may contain at least one 2,4,5-triarylimidazole dimer, or a 2-(2-chlorophenyl)-4,5-diphenylimidazole dimer, from the viewpoint of further improving photosensitivity and adhesion, and further suppressing the light absorption of component (C). The 2,4,5-triarylimidazole dimer may have a symmetric or asymmetric structure.

[0080] The content of component (C) may be 0.01 to 30 parts by mass, 0.1 to 10 parts by mass, 1 to 7 parts by mass, 1 to 6 parts by mass, 1 to 5 parts by mass, or 2 to 5 parts by mass, based on 100 parts by mass of the total solid content of components (A) and (B). When the content of component (C) is 0.01 parts by mass or more, the photosensitivity, resolution and adhesion tend to improve, and when it is 30 parts by mass or less, the resist pattern shape tends to be superior.

[0081] ((D) Photosensitizer) The photosensitive resin composition according to this embodiment may also contain (D) a photosensitizer (hereinafter also referred to as "component (D)"). By including component (D), it tends to be possible to effectively utilize the absorption wavelength of the active light used for exposure.

[0082] Examples of component (D) include pyrazolines, dialkylaminobenzophenones, anthracenes, coumarins, acridines, xanthones, oxazoles, benzoxazoles, thiazoles, benzothiazoles, triazoles, stilbenes, triazines, thiophenes, naphthalimides, and triarylamines. These can be used individually or in combination of two or more. From the standpoint of making more effective use of the absorption wavelength of the active light used for exposure, component (D) may include pyrazolines, anthracenes, coumarins, acridines, or dialkylaminobenzophenones, and more particularly may include coumarins, acridines, or dialkylaminobenzophenones, or dialkylaminobenzophenones. Examples of commercially available dialkylaminobenzophenones include "EAB" manufactured by Hodogaya Chemical Co., Ltd.

[0083] If component (D) is included, its content may be 1.0 part by mass or less, 0.5 parts by mass or less, 0.15 parts by mass or less, 0.12 parts by mass or less, or 0.10 parts by mass or less, based on 100 parts by mass of the total solid content of components (A) and (B). When the content of component (D) is 1.0 part by mass or less based on 100 parts by mass of the total solid content of components (A) and (B), deterioration of the resist pattern shape and resist bottom formation can be suppressed, and the resolution tends to be improved. Furthermore, from the viewpoint of easily obtaining high light sensitivity and good resolution, the content of component (D) may be 0.01 parts by mass or more based on 100 parts by mass of the total solid content of components (A) and (B).

[0084] ((E) Polymerization inhibitors) The photosensitive resin composition according to this embodiment may also contain (E) polymerization inhibitor (hereinafter also referred to as "component (E)"). By including component (E), it is possible to adjust the amount of exposure required to photocur the photosensitive resin composition to the optimal amount of exposure for exposure with a projection exposure machine. Examples of component (E) include alkyl catechols such as catechol, resorcinol (resorcinol), 1,4-hydroquinone, 2-methylcatechol, 3-methylcatechol, 4-methylcatechol, 2-ethylcatechol, 3-ethylcatechol, 4-ethylcatechol, 2-propylcatechol, 3-propylcatechol, 4-propylcatechol, 2-n-butylcatechol, 3-n-butylcatechol, 4-n-butylcatechol, 2-tert-butylcatechol, 3-tert-butylcatechol, 4-tert-butylcatechol, 3,5-di-tert-butylcatechol, and 2-methylresorcinol Examples include alkylresorcinols such as lucinol, 4-methylresorcinol, 5-methylresorcinol (orcinol), 2-ethylresorcinol, 4-ethylresorcinol, 2-propylresorcinol, 4-propylresorcinol, 2-n-butylresorcinol, 4-n-butylresorcinol, 2-tert-butylresorcinol, and 4-tert-butylresorcinol; alkylhydroquinones such as methylhydroquinone, ethylhydroquinone, propylhydroquinone, tert-butylhydroquinone, and 2,5-di-tert-butylhydroquinone; pyrogallol; and phloroglucin. These can be used individually or in combination of two or more.

[0085] (Other ingredients) The photosensitive resin composition according to this embodiment may optionally contain 0.01 to 20 parts by mass of each additive per 100 parts by mass of the total solid content of component (A) and component (B), such as dyes including malachite green, Victoria pure blue, brilliant green, and methyl violet; photochromicants including tribromophenylsulfone, leucocrystal violet, diphenylamine, benzylamine, triphenylamine, diethylaniline, and o-chloroaniline; thermal color inhibitors; plasticizers including p-toluenesulfonamide; pigments; fillers; defoamers; flame retardants; adhesion promoters; leveling agents; release accelerators; antioxidants; fragrances; imaging agents; and thermal crosslinking agents. These additives may be used individually or in combination of two or more.

[0086] Furthermore, the photosensitive resin composition according to this embodiment may optionally contain at least one organic solvent to improve the handling properties of the photosensitive composition and to adjust its viscosity and storage stability. Any commonly used organic solvent can be used as the organic solvent without particular limitation. Specifically, examples include methanol, ethanol, acetone, methyl ethyl ketone, methyl cellosolve, ethyl cellosolve, toluene, N,N-dimethylformamide, propylene glycol monomethyl ether, or mixtures thereof. These can be used individually or in combination of two or more.

[0087] <Protective layer> In this embodiment, the photosensitive element may also have a protective layer laminated on the side opposite to the side in contact with the barrier layer of the photosensitive layer. For example, a polymer film such as polyethylene or polypropylene may be used as the protective layer. Alternatively, a polymer film similar to the support film described above may be used, or a different polymer film may be used.

[0088] The following describes a method for manufacturing a photosensitive element in which a support film, a barrier layer, a photosensitive layer, and a protective layer are sequentially laminated.

[0089] <Method for manufacturing a photosensitive element> First, for example, a water-soluble resin containing polyvinyl alcohol is gradually added to a mixed solvent of water heated to 70-90°C and an organic solvent used as needed, so that the solids content is 10-20% by mass, and stirred for about 1 hour. Then, other components such as leveling agents are mixed in as needed to dissolve uniformly and obtain a resin composition for forming a barrier layer. In this specification, "solids" refers to the non-volatile components of the resin composition excluding volatile substances such as water and organic solvents. That is, it refers to components other than solvents such as water and organic solvents that remain without volatilizing during the drying process, and includes liquid, syrup-like, and wax-like substances at room temperature around 25°C.

[0090] Next, the barrier layer-forming resin composition is applied to the support film and dried to form a barrier layer. The application of the barrier layer-forming resin composition to the support film can be carried out by known methods such as roll coating, comma coating, gravure coating, air knife coating, die coating, bar coating, and spray coating.

[0091] Furthermore, the drying of the applied barrier layer-forming resin composition is not particularly limited as long as at least a portion of the solvent, such as water, can be removed, but it may be dried at 70 to 150°C for 5 to 30 minutes. After drying, the amount of residual solvent in the barrier layer may be 2% by mass or less from the viewpoint of preventing the diffusion of the solvent in subsequent processes.

[0092] Next, a photosensitive resin composition may be applied to the barrier layer of a support film, which has a barrier layer formed on it, in the same manner as the application of the resin composition for forming the barrier layer, and dried to form a photosensitive layer on the barrier layer. Then, by laminating a protective layer onto the photosensitive layer formed in this way, a photosensitive element comprising a support film, a barrier layer, a photosensitive layer, and a protective layer in this order can be produced. Alternatively, a photosensitive element comprising a support film, a barrier layer, a photosensitive layer, and a protective layer may be obtained by laminating a support film with a barrier layer formed on it and a protective layer with a photosensitive layer formed on it.

[0093] The thickness of the photosensitive layer in a photosensitive element can be appropriately selected depending on the application, but the thickness after drying may be 1 μm or more, 5 μm or more, or 10 μm or more, or it may be 200 μm or less, 100 μm or less, 50 μm or less, or less than 20 μm. When the thickness of the photosensitive layer is 1 μm or more, 5 μm or more, or 10 μm or more, industrial coating becomes easier and productivity tends to improve. Furthermore, when the thickness of the photosensitive layer is 200 μm or less, 100 μm or less, 50 μm or less, or less than 20 μm, the photosensitivity is high and the photocuring of the resist bottom is excellent, so it tends to be possible to form a resist pattern with excellent resolution and aspect ratio.

[0094] The melt viscosity of the photosensitive layer in a photosensitive element at 110°C can be appropriately selected depending on the type of substrate (underlay) in contact with the photosensitive layer, but after drying, it may be 50-10000 Pa·s, 100-5000 Pa·s, or 200-1000 Pa·s at 110°C. When the melt viscosity at 110°C is 50 Pa·s or higher, wrinkles and voids do not occur during the lamination process, and productivity tends to improve. Also, when the melt viscosity at 110°C is 10000 Pa·s or lower, adhesion to the underlay improves during the lamination process, and adhesion defects tend to be reduced.

[0095] The form of the photosensitive element according to this embodiment is not particularly limited. For example, it may be in the form of a sheet, or it may be wound in a roll on a core. When wound in a roll, the support film may be wound on the outside. Examples of materials for the core include polyethylene resin, polypropylene resin, polystyrene resin, polyvinyl chloride resin, or ABS resin (acrylonitrile-butadiene-styrene copolymer) and other plastics.

[0096] The end faces of the roll-shaped photosensitive element rolls obtained in this way may be fitted with end face separators for end face protection, or with moisture-proof end face separators for edge fusion resistance. As for packaging, they may be wrapped in a black sheet with low moisture permeability.

[0097] The photosensitive element according to this embodiment can be suitably used, for example, in a resist pattern formation method and a printed circuit board manufacturing method, which will be described later.

[0098] [Method for forming a resist pattern] The resist pattern formation method according to this embodiment comprises (i) the step of arranging a photosensitive layer, a barrier layer, and a support film on a substrate in this order from the substrate side using the photosensitive element (hereinafter also referred to as "(i) photosensitive layer and barrier layer formation step"), (ii) the step of removing the support film and exposing the photosensitive layer to active light through the barrier layer (hereinafter also referred to as "(ii) exposure step"), and (iii) the step of removing the uncured portions of the barrier layer and the photosensitive layer from the substrate (hereinafter also referred to as "(iii) development step"), and may include other steps as necessary. The resist pattern can also be called a photocured product pattern of a photosensitive resin composition or a relief pattern. Depending on the purpose, the resist pattern in this embodiment may be used as a resist or for other purposes such as a protective film.

[0099] (i) Photosensitive layer and barrier layer formation process) In the photosensitive layer and barrier layer formation process, the photosensitive layer and barrier layer are formed on the substrate using the photosensitive element described above. The substrate is not particularly limited, but typically a circuit formation substrate having an insulating layer and a conductive layer formed on the insulating layer, or a die pad (lead frame substrate) made of an alloy substrate is used.

[0100] One method for forming a photosensitive layer and a barrier layer on a substrate is, for example, when using a photosensitive element that has a protective layer, the protective layer is removed, and then the photosensitive layer of the photosensitive element is heated and pressed onto the substrate to form the photosensitive layer and barrier layer on the substrate. This results in a laminate comprising the substrate, the photosensitive layer, the barrier layer, and the support film in that order.

[0101] When performing the photosensitive layer and barrier layer formation process using a photosensitive element, it may be carried out under reduced pressure from the viewpoint of adhesion and conformability. Heating during crimping may be carried out at a temperature of 70 to 130°C, and crimping pressure may be 0.1 to 1.0 MPa (1 to 10 kgf / cm²). 2 The process may be carried out under the following pressures, but these conditions can be selected as needed. If the photosensitive layer of the photosensitive element is heated to 70-130°C, it is not necessary to preheat the substrate beforehand, but preheating the substrate can be done to further improve adhesion and conformability.

[0102] (ii) Exposure process In the exposure process, the support film is removed, and the photosensitive layer is exposed to active light through the barrier layer. As a result, the exposed area irradiated with active light may be photocured, forming a photocured area (latent image), or the unexposed area not irradiated with active light may be photocured, forming a photocured area. When the photosensitive layer and barrier layer are formed using the above photosensitive element, the support film present on the photosensitive layer is peeled off before exposure. By exposing the photosensitive layer through the barrier layer, a resist pattern with excellent resolution and resist pattern shape can be formed.

[0103] As for the exposure method, known exposure methods can be applied. Examples include a method of irradiating an active light in an image pattern through a negative or positive mask pattern called artwork (mask exposure method), an LDI (Laser Direct Imaging) exposure method, or a method of irradiating an image in an image pattern through a lens using an active light projected from the image of a photomask (projection exposure method). Among these, the projection exposure method may be used from the viewpoint of superior resolution. In other words, the photosensitive element, etc., according to this embodiment is applied to the projection exposure method. The projection exposure method can also be described as an exposure method that uses an active light with attenuated energy.

[0104] As a light source for the active light, there are no particular restrictions on any commonly used and known light sources. For example, carbon arc lamps, mercury vapor arc lamps, ultra-high pressure mercury lamps, high-pressure mercury lamps, xenon lamps, gas lasers such as argon lasers, solid-state lasers such as YAG lasers, and semiconductor lasers such as gallium nitride-based blue-violet lasers that effectively emit ultraviolet light can be used. Alternatively, light sources that effectively emit visible light, such as photographic floodlights and solar lamps, may also be used. Among these, from the viewpoint of improving resolution and alignment in a balanced manner, a light source that can emit i-line monochromatic light at an exposure wavelength of 365 nm, a light source that can emit h-line monochromatic light at an exposure wavelength of 405 nm, or a light source that can emit active light at an exposure wavelength of ihg mixed light may be used, and among these, a light source that can emit i-line monochromatic light at an exposure wavelength of 365 nm may be used. An example of a light source that can emit i-line monochromatic light at an exposure wavelength of 365 nm is an ultra-high pressure mercury lamp.

[0105] ((iii) Development process) In the development process, the uncured portions of the barrier layer and the photosensitive layer are removed from the substrate. The development process forms a resist pattern on the substrate consisting of the photocured portion of the photosensitive layer. If the barrier layer is water-soluble, it may be removed by washing with water, and then the uncured portions other than the photocured portion may be removed with a developer. If the barrier layer is soluble in the developer, the barrier layer may be removed with the developer along with the uncured portions other than the photocured portion. One example of a development method is wet development.

[0106] In the case of wet development, development can be carried out using a developer solution corresponding to the photosensitive resin composition and a known wet development method. Examples of wet development methods include the dip method, paddle method, high-pressure spray method, brushing, slapping, scrubbing, and agitation immersion method, and from the viewpoint of improving resolution, the high-pressure spray method is the most suitable. These wet development methods may be used individually or in combination of two or more methods.

[0107] The developer is appropriately selected according to the composition of the photosensitive resin composition described above. Examples include alkaline aqueous solutions and organic solvent developers.

[0108] From the standpoint of safety, stability, and good operability, an alkaline aqueous solution may be used as the developer. Examples of bases used in the alkaline aqueous solution include alkali hydroxides such as lithium, sodium, or potassium hydroxide; alkali carbonates such as lithium, sodium, potassium, or ammonium carbonates or bicarbonates; alkali metal phosphates such as potassium phosphate and sodium phosphate; alkali metal pyrophosphates such as sodium pyrophosphate and potassium pyrophosphate; sodium borate; sodium metasilicate; tetramethylammonium hydroxide; ethanolamine; ethylenediamine; diethylenetriamine; 2-amino-2-hydroxymethyl-1,3-propanediol; 1,3-diamino-2-propanol; and morpholine.

[0109] For example, dilute solutions of 0.1-5% by mass sodium carbonate, 0.1-5% by mass potassium carbonate, 0.1-5% by mass sodium hydroxide, or 0.1-5% by mass sodium tetraborate can be used as the alkaline aqueous solution for development. The pH of the alkaline aqueous solution used for development may be in the range of 9-11, and the temperature of the alkaline aqueous solution can be adjusted according to the developability of the photosensitive layer. In addition, for example, surfactants, defoamers, and small amounts of organic solvents to promote development may be mixed into the alkaline aqueous solution. Examples of organic solvents that can be used in the alkaline aqueous solution include 3-acetone alcohol, acetone, ethyl acetate, alkoxyethanol having alkoxy groups with 1-4 carbon atoms, ethyl alcohol, isopropyl alcohol, butyl alcohol, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, and diethylene glycol monobutyl ether.

[0110] Examples of organic solvents used in organic solvent developers include 1,1,1-trichloroethane, N-methylpyrrolidone, N,N-dimethylformamide, cyclohexanone, methyl isobutyl ketone, and γ-butyrolactone. These organic solvents may be prepared by adding water to these solvents in a range of 1 to 20% by mass to prevent ignition.

[0111] (Other processes) In the resist pattern formation method according to this embodiment, after removing the uncured portion in the development step, heating at 60 to 250°C or 0.2 to 10 J / cm² is applied as needed. 2 The process may also include a step of further curing the resist pattern by exposing it to a certain amount of light.

[0112] [Manufacturing method for printed circuit boards] The method for manufacturing a printed circuit board according to this embodiment includes a step of etching or plating a substrate on which a resist pattern has been formed by the resist pattern formation method described above to form a conductor pattern, and may also include other steps such as a resist pattern removal step as needed. The method for manufacturing a printed circuit board according to this embodiment can be suitably used for forming a conductor pattern by using the resist pattern formation method using the photosensitive element described above, but is more suitably applied to a method of forming a conductor pattern by plating. The conductor pattern can also be called a circuit.

[0113] In the etching process, a resist pattern formed on a substrate with a conductive layer is used as a mask to etch away the conductive layer of the substrate that is not covered by the resist, thereby forming a conductive pattern.

[0114] The etching method is appropriately selected depending on the conductive layer to be removed. Examples of etching solutions include cupric chloride solution, ferric chloride solution, alkaline etching solution, and hydrogen peroxide-based etching solution. Ferric chloride solution may also be used due to its favorable etch factor.

[0115] On the other hand, in the plating process, a resist pattern formed on a substrate with a conductive layer is used as a mask, and copper or solder is plated onto the conductive layer of the substrate that is not covered by the resist. After the plating process, the resist is removed by removing the resist pattern as described later, and then the conductive layer that was covered by this resist is etched to form a conductive pattern.

[0116] The plating method may be electrolytic plating or electroless plating, but electroless plating is preferable. Examples of electroless plating include copper plating such as copper sulfate plating and copper pyrophosphate plating, solder plating such as high-slow solder plating, nickel plating such as Watt bath (nickel sulfate-nickel chloride) plating and nickel sulfamate plating, and gold plating such as hard gold plating and soft gold plating.

[0117] After the etching or plating process described above, the resist pattern on the substrate is removed. The resist pattern can be removed, for example, by using an aqueous solution that is even more strongly alkaline than the alkaline aqueous solution used in the development process described above. Examples of such strongly alkaline aqueous solutions include 1-10% by mass sodium hydroxide aqueous solution and 1-10% by mass potassium hydroxide aqueous solution. Among these, 1-5% by mass sodium hydroxide aqueous solution or potassium hydroxide aqueous solution may also be used.

[0118] Methods for removing the resist pattern include, for example, immersion and spraying, which may be used individually or in combination.

[0119] After plating and removing the resist pattern, the desired printed circuit board can be manufactured by further etching the conductive layer covered with the resist to form a conductive pattern. The etching method used in this process is appropriately selected depending on the conductive layer to be removed. For example, the etching solution described above can be applied.

[0120] The method for manufacturing printed circuit boards according to this embodiment is applicable not only to the manufacture of single-layer printed circuit boards but also to the manufacture of multi-layer printed circuit boards, and is also applicable to the manufacture of printed circuit boards having small-diameter through-holes.

[0121] The method for manufacturing printed circuit boards according to this embodiment can be suitably used for manufacturing high-density package substrates, particularly for manufacturing printed circuit boards using the semi-additive method. An example of the manufacturing process for printed circuit boards using the semi-additive method is shown in Figure 2.

[0122] Figure 2(a) shows a substrate (circuit formation substrate) prepared, in which a conductive layer 40 is formed on an insulating layer 50. The conductive layer 40 is, for example, a copper layer. Figure 2(b) shows that the photosensitive layer 30 and barrier layer 20 are formed on the conductive layer 40 of the substrate by the photosensitive layer and barrier layer formation process described above. Figure 2(c) shows that the photosensitive layer 30 is irradiated with an active light 80 projected onto the photosensitive layer 30 through the barrier layer 20 by the exposure process, thereby forming a photocurable area on the photosensitive layer 30. Figure 2(d) shows that the resist pattern 32, which is a photocurable area, is formed on the substrate by the development process, which removes the areas other than the photocurable area formed by the exposure process (including the barrier layer) from the substrate. Figure 2(e) shows that a plating layer 60 is formed on the conductive layer 40 of the substrate that is not covered by the resist by a plating process using the resist pattern 32, which is a photocurable area, as a mask. In Figure 2(f), the resist pattern 32, which is the photocurable portion, is removed with a strong alkaline aqueous solution, and then the conductive layer 40, which was masked by the resist pattern 32, is removed by flash etching to form a conductive pattern 70 including the plated layer 62 after etching and the conductive layer 42 after etching. The conductive layer 40 and the plated layer 60 may be made of the same material or different materials. If the conductive layer 40 and the plated layer 60 are made of the same material, the conductive layer 40 and the plated layer 60 may be integrated. Although the projection exposure method is described in Figure 2, the resist pattern 32 may also be formed by using a combination of the mask exposure method and the LDI exposure method.

[0123] While preferred embodiments of this disclosure have been described above, this disclosure is not limited to the embodiments described above. [Examples]

[0124] The present disclosure will be described in more detail below based on examples, but the present disclosure is not limited to the following examples. Unless otherwise specified, "parts" and "%" are based on mass.

[0125] <Synthesis of Binder Polymer A-1> Solution (a) was prepared by mixing 270 g of polymerizable monomers (methacrylic acid), 500 g of styrene, 200 g of benzyl methacrylate, and 30 g of 2-hydroxyethyl methacrylate, along with 9 g of azobisisobutyronitrile. Solution (b) was prepared by mixing 1.4 g of azobisisobutyronitrile with a mixture of 160 g of 1-methoxy-2-propanol and 120 g of toluene. A mixture of 450 g of 1-methoxy-2-propanol and 380 g of toluene was placed in a flask equipped with a stirrer, reflux condenser, thermometer, dropping funnel, and nitrogen gas inlet tube. The mixture was then stirred while blowing nitrogen gas into the flask and heated to 80°C. Solution (a) was added to the mixture in the flask dropwise at a constant dropping rate over 4 hours, and then the mixture was stirred at 80°C for 2 hours. Next, solution (b) was added dropwise to the solution in the flask over 10 minutes at a constant dropping rate, and the solution in the flask was stirred at 80°C for 3 hours. Furthermore, the temperature of the solution in the flask was raised to 90°C over 30 minutes, and the solution was kept at 90°C for 6 hours. After that, stirring was stopped, and the solution was cooled to room temperature (25°C) to obtain the binder polymer A-1 solution. The non-volatile content (solids) of the binder polymer A-1 solution was 49% by mass. The weight-average molecular weight (Mw) of binder polymer A-1 was 35,000.

[0126] The weight-average molecular weight was measured by gel permeation chromatography (GPC) and derived by conversion using a calibration curve for standard polystyrene. The GPC conditions are as follows. (GPC conditions) Columns: Gelpack GL-R440, Gelpack GL-R450, and Gelpack GL-R400M (all manufactured by Showa Denko Materials Co., Ltd.) are linked together. Eluent: Tetrahydrofuran Measurement temperature: 40℃ Flow rate: 2.05mL / min Detector: Hitachi L-2490 RI (Hitachi, Ltd.)

[0127] <Preparation of resin composition for barrier layer formation> A barrier layer-forming resin composition was obtained by mixing each component shown in Table 1 in the amounts (unit: parts by mass) shown in the table. Specifically, the water-soluble resin was slowly added to a solvent at room temperature, stirred for 1 hour after the entire amount was added, and then the leveling agent was mixed in to dissolve it uniformly, thereby obtaining the barrier layer-forming resin composition. Note that the amount of water-soluble resin in Table 1 is the amount added in terms of solid content.

[0128] <Preparation of photosensitive resin composition> Next, a photosensitive resin composition was obtained by mixing each component shown in Table 1 in the amounts (unit: parts by mass) shown in the same table. Note that the amount of binder polymer in Table 1 is the amount added in solid content.

[0129] [Table 1]

[0130] The details of each component in Table 1 are as follows: (Water-soluble resin) *1: HC-100G (Polyvinyl alcohol, manufactured by Taisei Chemical Co., Ltd., product name: Maltite HC-100G, solids content 13.5% by mass) *2: K-30 (Polyvinylpyrrolidone, manufactured by Nippon Shokubai Co., Ltd., product name)

[0131] (Leveling agent) *3: WS-314 (Acrylic polymer, manufactured by Kyoeisha Chemical Co., Ltd., product name, ingredients: 48% by mass of acrylic polymer and 52% by mass of 3-methoxy-3-methyl-1-butanol, composition of acrylic polymer: copolymer of approximately 6.89 mol% butyl (meth)acrylate, approximately 61.4 mol% isobutyl (meth)acrylate and approximately 31.7 mol% terminal methoxy group EO-modified (meth)acrylate)

[0132] (A) Ingredients: Binder polymer *4: A-1 (Binder polymer A-1 obtained in synthesis example 1)

[0133] (B) Component: Photopolymerizable compound *5: FA-321M (Manufactured by Showa Denko Materials Co., Ltd., product name) 2,2-Bis(4-(methacryloxypolyethoxy)phenyl)propane(ethylene oxide adduct with an average of 10 mol) *6: FA-024M (Manufactured by Showa Denko Materials Co., Ltd., product name) (PO)(EO)(PO) Modified Dimethacrylate (Adduct of an average of 6 mol of ethylene oxide and an average of 12 mol of propylene oxide (total value)) *7: BP-2EM (manufactured by Kyoeisha Chemical Co., Ltd., product name) 2,2-Bis(4-(methacryloxypolyethoxy)phenyl)propane(EO group: 2.6 (total value))

[0134] (C) Ingredient: Photopolymerization initiator *8: B-CIM (manufactured by Hodogaya Chemical Co., Ltd., product name) 2,2'-Bis(2-chlorophenyl)-4,4',5,5'-tetraphenylbiimidazole

[0135] (D) Ingredients: Photosensitizer *9: PZ-501D (manufactured by Nippon Chemical Industrial Co., Ltd., product name) 1-Phenyl-3-(4-methoxystyryl)-5-(4-methoxyphenyl)-pyrazoline

[0136] (E) Ingredient: Polymerization inhibitor *10: Q-TBC-5P (Manufactured by DIC Corporation, product name) 4-tert-butylcatechol *11: LA-7RD (Manufactured by ADEKA Corporation, product name) 4-Hydroxy-2,2,6,6-tetramethylpiperidine-N-oxyl

[0137] Other ingredients *12: Leucocrystal violet (Yamada Chemical Industries Co., Ltd.) (colorant) *13: SF-808H (manufactured by Sanwa Kasei Co., Ltd., product name) (adhesion enhancer) A mixture of carboxybenzotriazole, 5-amino-1H-tetrazole, and methoxypropanol. *14: Malachite green (manufactured by Osaka Organic Chemical Industry Co., Ltd.) (dye)

[0138] [Examples 1-3, Comparative Examples 1 and 3] <Fabrication of photosensitive elements> (Preparation of support film) Five types of PET films A to E containing lubricants (particles) were prepared as support films for the photosensitive element. All PET films A to E have a thickness of 16 μm. Furthermore, the size and content of the lubricants (particles) differ for each of the PET films A to E. The following measurements were performed on PET films A to E. The results are shown in Table 2.

[0139] [Number of particles with a diameter of 0.8 μm or larger] For PET films A to E, the 0.0225 mm diameter of particles larger than 0.8 μm on the surface F1 that forms the barrier layer or photosensitive layer. 2 The number of particles per unit was measured using a laser microscope under the following conditions.

[0140] -Measurement conditions- Equipment: Hybrid laser microscope (manufactured by Lasertec Corporation, product name: OPTELICS HYBRID) Measurement range: 150 μm square Measurement details: Brightness image of the F1 surface of the PET film was acquired. The acquired brightness image was binarized to measure the particle (lubricant) size and number. Particles with a diameter of 0.8 μm or larger were measured at a 150 μm square (0.0225 mm) 2 The number of particles within the measurement range was calculated. Measurements were taken five times, and the average value was used as the particle count.

[0141] [Number of particles with a diameter of 5.0 μm or larger] For PET films A to E, the 0.0225 mm size of particles with a diameter of 5.0 μm or larger on surface F1 on the side forming the barrier layer or photosensitive layer. 2 The number of particles per unit area was measured using the same method as the measurement of the number of particles with a diameter of 0.8 μm or larger described above.

[0142] [Hayes] The haze of PET films A to E was measured using a turbidimeter (manufactured by Nippon Denshoku Industries Co., Ltd., product name "NDH-5000") in accordance with the method specified in JIS K7105.

[0143] [Linear expansion coefficient in the TD direction] The linear thermal expansion coefficients in the TD direction of PET films A to E were measured using the following method. First, test specimens were obtained by cutting the PET film into 3mm x 30mm pieces so that the TD direction was the longitudinal direction. The test specimens were set in a thermomechanical analyzer (Seiko Instruments Inc., SSC5200 model) in tensile mode with a chuck distance of 20mm. The set test specimens were processed under conditions of a temperature range of 20 to 250°C and a heating rate of 5°C / min, and the linear thermal expansion coefficient in the TD direction of the test specimens was measured. From the measurement results, the linear thermal expansion coefficient at 80 to 110°C was read. This linear thermal expansion coefficient is the average value at 80 to 110°C.

[0144] (Fabrication of barrier layer) Next, a barrier layer-forming resin composition was applied to the surface F1 of the PET film (support film) so as to be of uniform thickness, and dried in a hot air convection dryer at 95°C for 10 minutes to form a barrier layer with a thickness of 5 μm after drying.

[0145] (Preparation of the photosensitive layer) Next, a photosensitive resin composition was applied to the barrier layer to ensure uniform thickness, and dried in a 100°C hot air convection dryer for 10 minutes to form a photosensitive layer with a thickness of 15 μm after drying.

[0146] Next, a polyethylene protective film (protective layer) (manufactured by Tamapoly Co., Ltd., product name "NF-15A") was laminated onto this photosensitive layer to obtain a photosensitive element in which a PET film (support film), a barrier layer, a photosensitive layer, and a protective layer were laminated in this order.

[0147] [Comparative Example 2] <Fabrication of photosensitive elements> A photosensitive element was obtained in which a PET film (support film), a photosensitive layer, and a protective layer were laminated in the same order as in Example 2, except that a barrier layer was not provided.

[0148] [Comparative Example 4] <Fabrication of photosensitive elements> A photosensitive element was obtained in which a PET film (support film), a photosensitive layer, and a protective layer were laminated in the same order as in Comparative Example 3, except that a barrier layer was not provided.

[0149] [evaluation] <Fabrication of laminates> A Cu sputtered PET film (manufactured by Geomatec Co., Ltd., thickness: 125 μm, Ra < 50 nm) was heated to 80°C as the substrate, and the photosensitive elements were pressed onto the substrate so that the photosensitive layer was in contact with the copper surface while peeling off the protective layer. The pressing was performed using a 110°C heat roll at a pressure of 0.40 MPa and a roll speed of 1.0 m / min. In this way, laminates were obtained in which the substrate, photosensitive layer, barrier layer, and support film were laminated in this order (Examples 1-3, Comparative Examples 1 and 3), or laminates in which the substrate, photosensitive layer, and support film were laminated in this order (Comparative Examples 2 and 4). These laminates were used as test pieces in the tests described below. An HLM-3000 (manufactured by Taisei Laminator Co., Ltd., product name) was used as the laminator.

[0150] <Measuring the minimum development time> The support film was peeled off the test specimen to expose the barrier layer or photosensitive layer, and a 1% by mass aqueous solution of sodium carbonate at 30°C was sprayed onto it. The time until the photosensitive layer was completely removed was measured and defined as the minimum development time.

[0151] <Resist pattern formation> The support film was peeled off from the test pieces of Examples 1-3 and Comparative Examples 1 and 3. A glass-chromium type phototool (size: 9cm x 9cm, with three types of wiring patterns with line width / space width of 10μm / 10μm, 15μm / 15μm, and 20μm / 20μm evenly distributed, or an adhesive negative with a wiring pattern of line width / space width x / x (x: 1-18, unit: μm)) was placed on the exposed barrier layer as a negative. A projection exposure apparatus (manufactured by Ushio Inc., product name "UX-2240-SM-XJ01") using an ultra-high pressure mercury lamp (365nm) as a light source was used to expose the material at 110mJ / cm². 2 The photosensitive layer was exposed with the specified exposure dose. After exposure, a 1% by mass aqueous sodium carbonate solution at 30°C was sprayed for twice the minimum development time to remove the unexposed areas and form a resist pattern. The same procedure was repeated five times to prepare five resist patterns for evaluation.

[0152] On the other hand, for the test specimens of Comparative Examples 2 and 4, the above-mentioned phototool was placed on a support film, and a projection exposure apparatus (manufactured by Ushio Inc., product name "UX-2240-SM-XJ01") using an ultra-high pressure mercury lamp (365 nm) as the light source was used to expose them at 110 mJ / cm². 2 The photosensitive layer was exposed through a support film with the specified exposure dose. After exposure, the support film was peeled off to expose the photosensitive layer, and a 1% by mass aqueous sodium carbonate solution at 30°C was sprayed for twice the minimum development time to remove the unexposed areas and form a resist pattern. The same procedure was repeated five times to prepare five resist patterns for evaluation.

[0153] <Measurement of missing items> The resist pattern formed by the above method (in a 9 cm × 9 cm area, three types of resist patterns (length 9 cm) with line width / space width of 10 μm / 10 μm, 15 μm / 15 μm, and 20 μm / 20 μm are evenly provided over a width of 9 cm so that the number of each is the same) was inspected using an automatic optical inspection device (AOI, manufactured by Orbotech Japan Co., Ltd., product name "Ultra Fusion 600"), and the number of resist defect parts where the resist was missing by 5 μm or more was counted. The number of resist defect parts was counted for five resist patterns for evaluation, and the total was taken as the number of defects. The results are shown in Table 2.

[0154] <Measurement of LER> The LER (Line Edge Roughness) of the resist pattern formed by the above method was measured by the following method. That is, using a Computer Numerical Control image measurement system (manufactured by Nikon Corporation, product name "NEXIV VMZ-R4540"), an area where a resist pattern with a line width / space width of 5 μm / 5 μm was formed was imaged. In the scanning measurement of NEXIV VMZ-R4540, the contour of the resist pattern on the substrate was specified, and for six lines of the resist pattern, the coordinates of the contour of the resist pattern were measured. In the measurement of coordinates, the measurement of 260 points of coordinates engraved at 0.2 μm intervals over a length of 52 μm was performed for each of the contours on one side and the other side of the line. Also, these measurements were performed three times for each of the six lines. As a result, a total of 9360 points of coordinates were measured. Then, based on the measured 9360 points of coordinates, the variation (3σ) of the contour of the resist pattern was calculated. σ is the standard deviation, and the 3σ of the contour of the resist pattern is the LER (Line Edge Roughness). The results are shown in Table 2.

[0155] <Evaluation of Laminating Property> Copper-clad laminates (manufactured by Showa Denko Materials Co., Ltd., product name "MCL-E-679", size: 500 mm or more x 500 mm or more), which are glass epoxy materials with copper foil (thickness: 35 μm) laminated on both sides, were pickled and washed with water, air-dried, and heated to 80°C. While peeling off the protective layer, the photosensitive elements were pressed onto the copper-clad laminates so that the photosensitive layer was in contact with the copper surface. Pressing was performed using a 110°C heat roll at a pressure of 0.40 MPa and a roll speed of 1.0 m / min. After pressing, the presence or absence of voids between the copper-clad laminate and the photosensitive layer was observed and evaluated according to the evaluation criteria below. The results are shown in Table 2. A: No voids were observed. B: Voids were observed very rarely. C: Voids were rarely observed.

[0156] [Table 2] [Explanation of Symbols]

[0157] 1...Photosensitive element, 2...Support film, 3, 20...Barrier layer, 4, 30...Photosensitive layer, 5...Protective layer, 32...Resist pattern, 40...Conductive layer, 42...Conductive layer after etching, 50...Insulating layer, 60...Plated layer, 62...Plated layer after etching, 70...Conductive pattern, 80...Activated light.

Claims

1. A photosensitive element comprising a support film, a barrier layer, and a photosensitive layer in this order, The number of particles with a diameter of 0.8 μm or larger, measured on the barrier layer side surface of the support film, is 0.0225 mm. ２ Each item is between 5 and 100. A photosensitive element wherein the barrier layer contains a leveling agent comprising a copolymer having structural units selected from the group consisting of butyl (meth)acrylate, isobutyl (meth)acrylate, and terminal methoxy group EO-modified (meth)acrylate.

2. The photosensitive element according to claim 1, wherein the coefficient of linear expansion of the support film in the TD direction at 80 to 110°C is 170 ppm / K or less.

3. The photosensitive element according to claim 1, wherein the barrier layer comprises a water-soluble resin.

4. The photosensitive element according to claim 1, wherein the thickness of the barrier layer is 2 to 12 μm.

5. The number of particles with a diameter of 5.0 μm or larger, measured on the barrier layer side surface of the support film, is 0.0225 mm. ２ The photosensitive element according to claim 1, wherein there are 0 per unit.

6. A step of arranging a photosensitive layer, a barrier layer, and a support film on a substrate in this order from the substrate side, using a photosensitive element according to any one of claims 1 to 5, The steps include removing the support film and exposing the photosensitive layer to active light through the barrier layer, A step of removing the uncured portion of the photosensitive layer and the barrier layer from the substrate, A method for forming a resist pattern, comprising the characteristics of a resist pattern.

7. A method for manufacturing a printed wiring board, comprising the step of etching or plating a substrate on which a resist pattern has been formed by the resist pattern formation method described in claim 6 to form a conductor pattern.

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