WO2022019046A1

WO2022019046A1 - Photosensitive element, resist pattern forming method, and method for manufacturing printed wiring board

Info

Publication number: WO2022019046A1
Application number: PCT/JP2021/024156
Authority: WO
Inventors: 陽介賀口; 博史小野; 壮和粂
Original assignee: 昭和電工マテリアルズ株式会社
Priority date: 2020-07-20
Filing date: 2021-06-25
Publication date: 2022-01-27
Also published as: KR20230041976A; TW202206944A; JPWO2022019046A1; CN115867864A

Abstract

This photosensitive element comprises a support film, a barrier layer, and a photosensitive layer in this order, wherein the barrier layer contains a leveling agent.

Description

Photosensitive element, resist pattern forming method and printed wiring board manufacturing method

The present disclosure relates to a method for forming a photosensitive element, a resist pattern, and a method for manufacturing a printed wiring board.

Conventionally, in the field of manufacturing printed wiring boards, a photosensitive resin composition and a layer formed by using a photosensitive resin composition on a support film as a resist material used for etching treatment, plating treatment, etc. (hereinafter referred to as , Also referred to as a "photosensitive layer") is widely used.

The printed wiring board is manufactured by the following procedure, for example, using the above-mentioned photosensitive element. That is, first, the photosensitive layer of the photosensitive element is laminated on a circuit-forming substrate such as a copper-clad laminate. At this time, the surface of the photosensitive layer opposite to the surface in contact with the support film is laminated so as to be in close contact with the surface of the circuit forming substrate that forms the circuit. Further, laminating is performed, for example, by heat-pressing a photosensitive layer on a circuit-forming substrate (normal pressure laminating method).

Next, using a mask film or the like, a desired region of the photosensitive layer is exposed via the support film to generate radicals. The generated radicals pass through several reaction pathways and contribute to the cross-linking reaction (photo-curing reaction) of the photopolymerizable compound. Next, after peeling off the support film, the uncured portion of the photosensitive layer is dissolved or dispersed and removed with a developing solution to form a resist pattern. Next, using the resist pattern as a resist, an etching treatment or a plating treatment is performed to form a conductor pattern, and finally the photocured portion (resist pattern) of the photosensitive layer is peeled off (removed).

By the way, in recent years, it has been studied to use a photosensitive element having a barrier layer (intermediate layer) having a gas barrier property between a support film and a photosensitive layer (see, for example, Patent Document 1).

International Publication No. 2019/216353

However, the coating stability of the barrier layer is not always sufficient, and cissing is likely to occur when the barrier layer is formed on the support film, and the surface of the obtained barrier layer is defective (for example, a part of the barrier layer has a dent in the coating film). The base is exposed due to the occurrence, etc.). Defects on the surface of the barrier layer cause exposure defects, which causes resist defects. Further, the barrier layer has strong adhesion to the support film, and when the support film is peeled off, a part of the barrier layer may be peeled off together with the support film while being attached to the support film, and the barrier layer may be damaged.

The present disclosure has been made in view of the above-mentioned problems of the prior art, and is a photosensitive element and a resist that can reduce the number of defects on the surface of the barrier layer and suppress the defect of the barrier layer when the support film is peeled off. It is an object of the present invention to provide a method for forming a pattern and a method for manufacturing a printed wiring board.

In order to achieve the above object, the present disclosure provides a photosensitive element comprising a support film, a barrier layer, and a photosensitive layer in this order, wherein the barrier layer contains a leveling agent. offer.

In the photosensitive element of the present disclosure, since the barrier layer contains a leveling agent, repelling can be suppressed due to a decrease in surface tension, the number of defects on the surface can be reduced, and the adhesion between the barrier layer and the support film can be reduced. It is possible to prevent the barrier layer from being damaged when the support film is peeled off.

In the photosensitive element, the leveling agent has a copolymer weight derived from at least one selected from the group consisting of butyl (meth) acrylate, isobutyl (meth) acrylate, and terminal methoxy group EO-modified (meth) acrylate. May include coalescence. When the leveling agent contains the above-mentioned copolymer, the number of surface defects of the barrier layer can be further reduced, and the defect of the barrier layer when the support film is peeled off can be more sufficiently suppressed.

In the photosensitive element, the barrier layer may contain polyvinyl alcohol. When the barrier layer contains polyvinyl alcohol, the gas barrier property of the barrier layer can be further improved, and the deactivation of radicals generated by the active light rays used for exposure can be further suppressed.

In the photosensitive element, the thickness of the barrier layer may be 2 to 12 μm.

In the photosensitive element, the photosensitive layer may contain a bisphenol A type di (meth) acrylate compound. The photosensitive layer is composed of 2,2-bis (4-((meth) acryloxipentethoxy) phenyl) propane and / or 2,2-bis (4-((meth) acryloxidiethoxy) phenyl) propane. May include.

The present disclosure also includes a step of arranging a photosensitive layer, a barrier layer, and a supporting film on a substrate in this order from the substrate side using the photosensitive element of the present disclosure, and removing the supporting film. Provided is a method for forming a resist pattern, which comprises a step of exposing the photosensitive layer with an active light via a barrier layer and a step of removing the uncured portion of the photosensitive layer and the barrier layer from the substrate. According to such a resist pattern forming method, since the resist pattern is formed by using the photosensitive element of the present disclosure, it is possible to form a resist pattern having few defects.

The present disclosure further provides a method for manufacturing a printed wiring board, which comprises 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 of the present disclosure. According to the method for manufacturing a printed wiring board, since the resist pattern is formed by the resist pattern forming method of the present disclosure, a resist pattern with few defects can be formed, which is suitable for increasing the density of the printed wiring board. A method for manufacturing a printed wiring board can be provided.

According to the present disclosure, there are provided a photosensitive element capable of reducing the number of defects on the surface of the barrier layer and suppressing the defect of the barrier layer when the support film is peeled off, a method for forming a resist pattern, and a method for manufacturing a printed wiring board. can do.

It is a schematic cross-sectional view which shows one Embodiment of the photosensitive element of this disclosure. It is a figure which shows an example of the manufacturing process of the printed wiring board by the semi-additive method schematically.

Hereinafter, preferred embodiments of the present disclosure will be described in detail with reference to the drawings as necessary. Needless to say, in the following embodiments, the components (including element steps and the like) are not necessarily essential unless otherwise specified or clearly considered to be essential in principle. This also applies to numbers and ranges and should be construed as not unreasonably limiting this disclosure.

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

Further, in the present specification, the term "process" is used not only as an independent process but also as long as the intended action of the process is achieved even if it cannot be clearly distinguished from other processes. included.

Further, the numerical range indicated by using "-" in the present specification indicates a range including the numerical values before and after "-" as the minimum value and the maximum value, respectively. Further, in the numerical range described stepwise in the present specification, the upper limit value or the lower limit value of the numerical range of one step may be replaced with the upper limit value or the lower limit value of the numerical range of another step. Further, in the numerical range described in the present specification, the upper limit value or the lower limit value of the numerical range may be replaced with the value shown in the examples. Further, in the present specification, the term "layer" includes not only a structure having a shape formed on the entire surface but also a structure having a shape partially formed when observed as a plan view.

[Photosensitive element]
As shown in FIG. 1, the photosensitive element 1 of the present embodiment includes a support film 2, a barrier layer 3, and a photosensitive layer 4 in this order, and may further include other layers such as a protective layer 5. good. Further, the barrier layer 3 contains a leveling agent. Hereinafter, each layer of the photosensitive element according to the present embodiment will be described in detail.

<Support film>
The support film of the present embodiment can be used without particular limitation. Examples of the support film include polyester films such as polyethylene terephthalate (PET), polybutylene terephthalate (PBT) and polyethylene-2,6-naphthalate (PEN), and polyolefin films such as polypropylene and polyethylene. Above all, a polyester film may be used. By using a polyester film as the support film, there is a tendency that the mechanical strength and heat resistance of the support film can be improved. Further, by using the polyester film, defects such as wrinkles of the barrier layer generated when the barrier layer is formed on the support film can be suppressed, and workability tends to be improved. Further, a polyester film containing particles (lubricant or the like) may be used from the viewpoint of suppressing the occurrence of minute omission of the resist pattern. When a polyester film containing particles (lubricant or the like) is used, a barrier layer may be formed on the surface having the particles (lubricant or the like). Examples of such a polyester film include a polyester film in which particles (lubricant, etc.) are kneaded, a polyester film having a layer containing particles (lubricant, etc.) on both sides, or particles (lubricant, etc.) on one side. ) May be used to form a layer containing the polyester film. The support film may be a single layer or a multilayer.

As a method of adding particles such as lubricant to the support film, for example, a method of kneading particles (lubricant, etc.) into the support film, a layer containing particles (lubricant, etc.) on the support film, roll coating, and flow. Examples thereof include a method of forming by using a known method such as a coat, a spray coat, a curtain flow coat, a dip coat, and a slit die coat.

Even if the haze of the support film is 0.01 to 5.0%, 0.01 to 1.5%, 0.01 to 1.0%, or 0.01 to 0.5%. good. When this haze is 0.01% or more, the support film itself tends to be easy to manufacture, and when it is 5.0% or less, when the photosensitive layer of the photosensitive element is formed, foreign matter in the photosensitive layer is formed. Tends to be easier to detect. Here, "haze" means the degree of cloudiness. The haze in the present disclosure refers to a value measured using a commercially available turbidity meter (turbidity meter) in accordance with the method specified in JIS K7105. The haze can be measured with a commercially available turbidity meter such as NDH-5000 (manufactured by Nippon Denshoku Kogyo Co., Ltd., trade name).

Further, as the support film, a commercially available general industrial film that can be used as a support film for the photosensitive element may be obtained and appropriately processed and used. Specifically, for example, PET films "FB-40", "QS69", "FS-31" (manufactured by Toray Industries, Inc., product name), "A4100", "A1517" (manufactured by Toyobo Co., Ltd., Product name), "G2H" (manufactured by Teijin DuPont Film Co., Ltd., product name), "R-705G" (manufactured by Mitsubishi Chemical Co., Ltd., product name) and the like.

The thickness of the support film may be 1 to 200 μm, 1 to 100 μm, 1 to 60 μm, 5 to 60 μm, 10 to 60 μm, 10 to 50 μm, 10 to 40 μm, 10 to 30 μm, or 10 to 25 μm. When the thickness of the support film is 1 μm or more, it tends to be possible to prevent the support film from being torn when the support film is peeled off. Further, when the thickness of the support film is 200 μm or less, it tends to be easy to obtain economic benefits.

<Barrier layer>
The photosensitive element of the present embodiment includes a barrier layer between the support film and the photosensitive layer. The barrier layer also contains a leveling agent. The barrier layer may be a layer formed by using the resin composition for forming the barrier layer. The resin composition for forming a barrier layer of the present embodiment contains a leveling agent, and may further contain a water-soluble resin and water. Further, the barrier layer may have water solubility or solubility in a developing solution. From the viewpoint of further improving the gas barrier property of the barrier layer, the adhesive force between the support film and the barrier layer may be smaller than the adhesive force between the barrier layer and the photosensitive layer. In this case, when the support film is peeled from the photosensitive element, unintentional peeling between the barrier layer and the photosensitive layer can be suppressed.

(Leveling agent)
The leveling agent is oriented on the surface of the coating film and equalizes the tension on the surface of the coating film. Examples of the leveling agent include acrylic polymers, vinyl-based, silicone-based, and fluorine-based agents. The leveling agent is preferably an acrylic polymer from the viewpoint of transferability to a photosensitive element and solubility in a developing solution. The acrylic polymer keeps the adhesion between the barrier layer and the support film in an appropriate range, and makes the adhesive force between the support film and the barrier layer smaller than the adhesive force between the barrier layer and the photosensitive layer, while unintentional between the layers. From the viewpoint of suppressing peeling and from the viewpoint of easily suppressing the occurrence of defects on the surface of the barrier layer when the barrier layer is formed on the support film (less likely to cause repelling), butyl (meth) acrylate and isobutyl (meth). ) Acrylate and a copolymer having a structural unit derived from at least one selected from the group consisting of a terminal methoxy group EO-modified (meth) acrylate, preferably a butyl (meth) acrylate and an isobutyl (meth) acrylate. It is more preferable to include a polymer having a structural unit derived from, and a polymer having a structural unit derived from butyl (meth) acrylate, isobutyl (meth) acrylate, and terminal methoxy group EO-modified (meth) acrylate. It is more preferable to include it.

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

The content of the leveling agent in the barrier layer is 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 defect of the barrier layer when the support film is peeled off. , 0.05 to 1.0% by mass, 0.1 to 0.7% by mass, or 0.2 to 0.5% by mass.

(Water-soluble resin)
The barrier layer may contain a water-soluble resin. Here, "water soluble resin" means a resin solubility is less than 5g / _100mL-C _{6 H 14} against hexanes 100mL of 25 ° C.. This solubility can be calculated by mixing hexane at 25 ° C. with a dried water-soluble resin and examining the presence or absence of cloudiness. Specifically, sample 1 obtained by putting a mixed solution of dried water-soluble resin A (g) and 100 mL of hexane in a colorless and transparent glass container with a ground glass stopper, and 100 mL of hexane only are put. Prepare each of the obtained samples 2. Then, after sufficiently shaking the sample in the glass container, it is confirmed that the bubbles have disappeared. Immediately after confirmation, both containers are placed side by side under diffuse daylight or equivalent light, and the state of the liquid of sample 1 and the state of the liquid of sample 2 are compared. Comparing Sample 1 and Sample 2, the addition amount A (g) when sample 1 began to be observed to be more cloudy or solid content was to be observed to float was determined by hexane at 25 ° C. of the water-soluble resin. The solubility in 100 mL.

Examples of the water-soluble resin include polyvinyl alcohol, polyvinylpyrrolidone, and water-soluble polyimides. The water-soluble resin may contain polyvinyl alcohol from the viewpoint of further improving the gas barrier property of the barrier layer and further suppressing the deactivation of radicals generated by the active light rays used for exposure. Polyvinyl alcohol can be obtained, for example, by saponifying polyvinyl acetate obtained by polymerizing vinyl acetate. The saponification degree of 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 the saponification degree is 100 mol%. By containing polyvinyl alcohol having a saponification degree of 50 mol% or more, there is a tendency that the gas barrier property of the barrier layer can be further improved and the resolution of the formed resist pattern can be further improved. The "saponification degree" in the present specification means a value measured in accordance with JIS K 6726 (1994) (polyvinyl alcohol test method) specified in Japanese Industrial Standards.

As the polyvinyl alcohol, two or more kinds having different saponification degree, viscosity, degree of polymerization, modified kind and the like may be used in combination. The average degree of polymerization of polyvinyl alcohol may be 300 to 5000, 300 to 3500, or 300 to 2000. In addition, the water-soluble resin may be used alone or in combination of two or more. The water-soluble resin may contain, for example, polyvinyl alcohol and polyvinylpyrrolidone. In this case, the mass ratio of polyvinyl alcohol to polyvinylpyrrolidone (PVA: PVP) may be 40:60 to 90:10, 50:50 to 90:10, or 60:40 to 90:10.

The content of the water-soluble resin in the resin composition for forming the barrier layer of the present embodiment is 50 to 300 parts by mass, 60 to 250 parts by mass, and 70 to 200 parts by mass with respect to 500 parts by mass of water from the viewpoint of improving the gas barrier property. It may be parts by mass, 80 to 150 parts by mass, or 80 to 125 parts by mass.

The content of the water-soluble resin in the barrier layer is 99 based on the total solid content of the barrier layer from the viewpoint of improving the gas barrier property, the peelability between the support film and the barrier layer, and the solubility in the developing solution. It may be 0.0 to 99.95% by mass, 99.3 to 99.9% by mass, or 99.5 to 99.8% by mass.

(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. The ultraviolet absorber may have a maximum absorption wavelength in the wavelength range of 250 nm to 500 nm from the viewpoint of further improving the resolution. By containing these ultraviolet absorbers, the resolution can be improved.

The i-ray absorption rate of the ultraviolet absorber may be 5 to 95%, 10 to 90%, or 15 to 75%. The i-ray absorption rate can be measured by an ultraviolet-visible spectrophotometer.

The above-mentioned ultraviolet absorber may be used alone or in combination of two or more. Further, the solubility of the ultraviolet absorber in water at 20 ° C. is 0.01 g / 100 mL-H ₂ O or more and 0.1 g / 100 mL-H _{2 from the viewpoint of suppressing aggregation and precipitation of the ultraviolet absorber in the barrier layer.} It may be O or more, or 1 g / 100 mL-H ₂ O or more.

Examples of the ultraviolet absorber include oxybenzophenone compounds, triazole compounds, benzotriazole compounds, salicylic acid ester compounds, benzophenone compounds, diphenyl acrylate compounds, cyanoacrylate compounds, diphenyl cyanoacrylate compounds, iron or nickel complex salt compounds and the like. Among these, an oxybenzophenone compound and a benzophenone compound are preferable, a benzophenone sulfonic acid compound is more preferable, and an oxybenzophenone sulfonic acid compound is further preferable, from the viewpoint of further improving the resolution. The "benzophenone sulfonic acid compound" is a compound having a sulfo group in the benzophenone compound, and the benzophenone sulfonic acid compound may be a hydrate. These compounds have a hydrophilic sulfo group in the benzophenone skeleton, which makes the benzophenone skeleton more compatible with the resist, while the sulfo group has a higher affinity with the barrier layer, resulting in resolution and removal of the barrier layer. I presume that it is possible to achieve both sex. Further, among the oxybenzophenone compounds, 2-hydroxy-4-methoxybenzophenone-5-sulfonic acid hydrate represented by the following formula (1) is preferable.

The barrier layer of the present embodiment may have an absorbance of 0.01 to 2.0 or 0.1 to 1.0 for light having a wavelength of 365 nm. When the absorbance is 0.01 or more, a better resolution tends to be obtained, and when the absorbance is 2.0 or less, the resist pattern shape of the obtained resist pattern tends to be better. The absorbance of the barrier layer can be measured using, for example, a UV spectrophotometer (Spectrophotometer U-3310, manufactured by Hitachi, Ltd.). For the measurement, a laminated film having a barrier layer of an arbitrary thickness formed on the support film is placed on the measurement side, the support film is placed on the reference side, and the wavelength of 300 to 700 nm is continuously measured by the absorbance mode, and the value at the wavelength of 365 nm is measured. It is done by reading.

(Other ingredients)
The resin composition for forming a barrier layer of the present 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 plasticizer of the polyhydric alcohol compound described later). Alcohols having 3 or more carbon atoms may contain at least one selected from the group consisting of the compounds represented by the following chemical formulas (2) to (4) and the compounds represented by the following general formula (5). good. By containing these alcohols having 3 or more carbon atoms, the peelability between the barrier layer and the support film can be improved. Therefore, when the support film is peeled from the photosensitive element, unintentional peeling between the barrier layer and the photosensitive layer can be suppressed, and deterioration of gas barrier property and resolution due to such unintentional peeling can be suppressed. be able to.

In the general formula (5), R ¹¹ represents an alkyl group and R ¹² represents an alkylene group. Further, the sum of the carbon atoms of ^{the group of R 11 and} the group of R ^{12 is 3 or more.} Further, ^{the sum of the carbon atoms of the group of R 11 and} the group of R ¹² may be 10 or less, 8 or less, 7 or less, or 5 or less from the viewpoint of further improving the affinity with water. The ^{alkyl group represented by R 11} may be an alkyl group having 1 to 4 ^{carbon atoms, and the alkylene group represented by R 12} may be an alkylene group having 1 to 3 carbon atoms. Further, the alcohol having 3 or more carbon atoms represented by the general formula (5) may be 2-butoxy-ethanol or 1-methoxy-2-propanol.

The alcohols having 3 or more carbon atoms may be used alone or in combination of two or more. Further, the solubility of alcohols having 3 or more carbon atoms in water at 20 ° C. is 300 mL / 100 mL-H ₂ O or more, 500 mL / 100 mL-H ₂ O or more, or 500 mL / 100 mL-H 2 O or more, from the viewpoint of further suppressing the layer separation of the barrier layer. It may be 1000 mL / 100 mL-H ₂ O or more.

The "solubility of alcohols having 3 or more carbon atoms in water at 20 ° C." in the present specification can be calculated by mixing the alcohols with water at 20 ° C. and examining the presence or absence of cloudiness. Specifically, it was obtained by putting Sample 3 obtained by putting a mixed solution of the alcohols AmL and 100 mL of water into a colorless and transparent glass container with a rubbed glass stopper, and putting only water (100 mL) into it. Prepare each sample 4. Next, after sufficiently shaking each of the sample 3 and the sample 4 in the glass container, it is confirmed that the bubbles have disappeared. Immediately after confirmation, both containers are arranged side by side under diffuse daylight or equivalent light, and the state of the liquid in the sample 3 and the state of the liquid in the sample 4 are compared. The sample 3 and the sample 4 are compared, and the addition amount AmL of the alcohols when the sample 3 is observed to be more cloudy is defined as the solubility of the alcohols in water at 20 ° C.

The content of alcohols having 3 or more carbon atoms in the resin composition for forming a barrier layer of the present embodiment may be 100 to 500 parts by mass or 125 to 450 parts by mass with respect to 500 parts by mass of water. .. When this content is 100 parts by mass or more, the peelability between the formed barrier layer and the support film tends to be improved, and when it is 500 parts by mass or less, the solubility of the water-soluble resin is improved and the barrier. Layers tend to be easier to form.

The content of alcohols having 3 or more carbon atoms in the barrier layer of the present embodiment is more than 0% by mass and 2 based on the total amount of the barrier layer (total solid content of the resin composition for forming the barrier layer forming the barrier layer). It may be 0.0% by mass or less, 0.001 to 2.0% by mass, or 0.005 to 1.0% by mass. When this content is 2.0% by mass or less, the diffusion of alcohols in a later step tends to be suppressed, and when it is 0.001% by mass or more, the barrier layer and the support film are peeled off. There is a tendency for sex to improve.

The resin composition for forming a barrier layer of the present embodiment may contain alcohols having less than 3 carbon atoms. When the alcohol having less than 3 carbon atoms is contained, the content thereof may be 125 to 375 parts by mass or 150 to 325 parts by mass with respect to 500 parts by mass of water. When this content is 125 parts by mass or more, the solubility of the water-soluble resin is improved and the barrier layer tends to be easily formed, and when it is 375 parts by mass or less, it supports the formed barrier layer. The peelability from the film tends to be improved. Further, the content of alcohols having less than 3 carbon atoms in the barrier layer of the present embodiment is based on the total amount of alcohols having 3 or more carbon atoms in the barrier layer from the viewpoint of improving the peelability between the barrier layer and the support film. Even if it is 0.1 to 10% by mass (that is, the amount of alcohols having less than 3 carbon atoms is 0.1 to 10 parts by mass with respect to 100 parts by mass of the total amount of alcohols having 3 or more carbon atoms). good.

Further, the barrier layer and the resin composition for forming the barrier layer of the present embodiment may contain known additives such as a plasticizer and a surfactant as long as the effects of the present disclosure are not impaired. Further, a peeling accelerator may be contained as long as the effect of the present disclosure is not impaired.

The barrier layer in the photosensitive element of the present embodiment can be formed, for example, by applying the resin composition for forming the barrier layer of the present embodiment on a support film and drying it. When the resin composition for forming a barrier layer of the present embodiment is applied on the support film, the leveling agent tends to be unevenly distributed on the surface side of the support film in the coating film. As a result, the surface tension of the resin composition for forming the barrier layer is likely to decrease, and repelling is likely to be suppressed. Further, in the barrier layer, the leveling agent is unevenly distributed on the surface side of the support film, so that the adhesive force between the support film and the barrier layer tends to decrease.

The thickness of the barrier layer is not particularly limited. 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 from the viewpoint of easy removal 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 from the viewpoint of ease of forming the barrier layer and resolution. Further, from the viewpoint of suppressing 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.

<Photosensitive layer>
The photosensitive layer of this embodiment is a layer formed by using a photosensitive resin composition described later. The photosensitive resin composition can be used according to a desired purpose as long as the properties change (for example, photocuring) when irradiated with light, and the photosensitive resin composition may be a negative type or a positive type. May be good. The photosensitive resin composition may contain (A) a binder polymer, (B) a photopolymerizable compound, and (C) a photopolymerization initiator. Further, if necessary, (D) a photosensitizer, (E) a polymerization inhibitor or other components may be contained. Hereinafter, each component used in the photosensitive resin composition in the present embodiment will be described in more detail.

((A) Binder polymer)
The (A) binder polymer (hereinafter, also referred to as “component (A)”) can be produced, for example, by radically polymerizing a polymerizable monomer. Examples of the polymerizable monomer include a polymerizable styrene derivative substituted with an α-position or an aromatic ring such as styrene, vinyltoluene and α-methylstyrene, acrylamide such as diacetoneacrylamide, acrylic nitrile, and vinyl. Vinyl alcohol ethers such as -n-butyl ether, (meth) acrylic acid alkyl ester, (meth) acrylic acid benzyl ester such as benzyl methacrylate, (meth) acrylic acid tetrahydrofurfuryl ester, (meth) acrylic acid dimethylaminoethyl Estel, (meth) acrylic acid diethylaminoethyl ester, (meth) acrylic acid glycidyl ester, 2,2,2-trifluoroethyl (meth) acrylate, 2,2,3,3-tetrafluoropropyl (meth) acrylate, ( Meta) Acrylic acid, α-bromoacrylic acid, α-chloracrylic acid, β-frill (meth) acrylic acid, β-styryl (meth) acrylic acid, maleic acid, maleic acid anhydride, monomethyl maleate, monoethyl maleate , Maleic acid monoester such as monoisopropyl maleic acid, fumaric acid, silicic acid, α-cyanoacrylic acid, itaconic acid, crotonic acid and propioleic acid. These can be used alone or in combination of two or more.

Among these, a (meth) acrylic acid alkyl ester may be contained from the viewpoint of improving plasticity. Examples of the (meth) acrylic acid alkyl ester include compounds represented by the following general formula (II) and compounds in which the alkyl group of these compounds is replaced with a hydroxyl group, an epoxy group, a halogen group or the like.
H ₂ C = C (R ⁶ ) -COOR ⁷ (II)

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

Examples of the (meth) acrylic acid alkyl ester represented by the general formula (II) include (meth) acrylic acid methyl ester, (meth) acrylic acid ethyl ester, (meth) acrylic acid propyl ester, and (meth) acrylic. Acid butyl ester, (meth) acrylic acid pentyl ester, (meth) acrylic acid hexyl ester, (meth) acrylic acid heptyl ester, (meth) acrylic acid octyl ester, (meth) acrylic acid 2-ethylhexyl ester, (meth) acrylic Examples thereof include acid nonyl ester, (meth) acrylic acid decyl ester, (meth) acrylic acid undecyl ester, and (meth) acrylic acid dodecyl ester. These can be used alone or in combination of two or more.

Further, the component (A) may contain a carboxyl group from the viewpoint of alkali developability. The component (A) containing a carboxyl group can be produced, for example, by radically polymerizing a polymerizable monomer having a carboxyl group and another polymerizable monomer. The polymerizable monomer having a carboxyl group may be (meth) acrylic acid or methacrylic acid. Further, the acid value of the component (A) containing a carboxyl group may be 50 to 250 mgKOH / g, 50 to 200 mgKOH / g, or 100 to 200 mgKOH / g.

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

The content of the structural unit derived from the polymerizable monomer having a carboxyl group in the component (A) correlates with the compounding ratio of the polymerizable monomer having a carboxyl group, and thus is 12 to 50% by mass. , 12-40% by mass, 15-35% by mass, 15-30% by mass, or 20-30% by mass.

Further, as the component (A), styrene or a styrene derivative may be used as the polymerizable monomer from the viewpoint of adhesion and chemical resistance. When the above-mentioned styrene or styrene derivative is used as a polymerizable monomer, its content (the mixing ratio of styrene or styrene derivative with respect to the total amount of the polymerizable monomer used for the component (A)) determines the adhesion and chemical resistance. From the viewpoint of further improvement, it may be 10 to 60% by mass, 15 to 50% by mass, 30 to 50% by mass, 35 to 50% by mass, or 40 to 50% by mass. When this content is 10% by mass or more, the adhesion tends to be improved, and when it is 60% by mass or less, it is possible to suppress the size of the peeled pieces during development, and the time required for peeling tends to be long. be.

Since the content of the structural unit derived from styrene or the styrene derivative in the component (A) correlates with the blending ratio of the styrene or the styrene derivative, it is 10 to 60% by mass, 15 to 50% by mass, and 30 to 50. It may be% by mass, 35 to 50% by mass, or 40 to 50% by mass.

Further, as the component (A), (meth) acrylic acid benzyl ester may be used as the polymerizable monomer from the viewpoint of resolution and aspect ratio. The content of the structural unit derived from the (meth) acrylic acid benzyl ester in the component (A) is 15 to 50% by mass, 15 to 45% by mass, and 15 to 40% by mass from the viewpoint of further improving the resolution and the aspect ratio. %, 15 to 35% by mass, or 20 to 30% by mass.

These binder polymers can be used alone or in combination of two or more. When two or more kinds are used in combination, the component (A) includes, for example, two or more kinds of binder polymers composed of different polymerizable monomers, two or more kinds of binder polymers having different weight average molecular weights, and different dispersions. Two or more kinds of binder polymers can be mentioned.

The component (A) can be produced by a usual method. Specifically, for example, it can be produced by radical polymerization of (meth) acrylic acid alkyl ester, (meth) acrylic acid, styrene and the like.

The weight average molecular weight of the component (A) is 20,000 to 300,000, 40,000 to 150,000, 40,000 to 120,000, or from the viewpoint of improving mechanical strength and alkali developability in a well-balanced manner. It may be 50,000 to 80,000. When the weight average molecular weight of the component (A) is 20,000 or more, the developer tendency is excellent, and when the weight average molecular weight is 300,000 or less, the development time tends to be suppressed. The weight average molecular weight in the present specification is a value measured by gel permeation chromatography (GPC) and converted by a calibration curve prepared using standard polystyrene.

The content of the component (A) is 30 to 80 parts by mass, 40 to 75 parts by mass, and 50 to 70 parts by mass with respect to 100 parts by mass of the total solid content of the component (A) and the component (B) described later. Alternatively, it may be 50 to 60 parts by mass. When the content of the component (A) is within this range, the coating film property and the strength of the photocurable portion of the photosensitive resin composition become better.

((B) Photopolymerizable compound)
The photosensitive resin composition according to the present embodiment may contain (B) a photopolymerizable compound (hereinafter, also referred to as “(B) component”). The component (B) can be used without particular limitation as long as it is a photopolymerizable compound or a photocrosslinkable compound, and for example, a compound having at least one ethylenically unsaturated bond in the molecule may be used. can.

As the component (B), a bisphenol type (meth) acrylate compound may be contained. Examples of the bisphenol type (meth) acrylate compound include 2,2-bis (4-((meth) acryloxypolyethoxy) phenyl) propane and 2,2-bis (4-((meth) acryloxypolypropoxy)). Phenyl) propane, 2,2-bis (4-((meth) acryloxypolyethoxypolypropoxy) phenyl) propane and the like can be mentioned. These can be used alone or in combination of two or more. Further, as the bisphenol type (meth) acrylate compound, 2,2-bis (4- (methacryloxypentethoxy) phenyl) propane and 2,2-bis (4- (methacryloxydiethoxy) phenyl) propane are contained. May be good.

Commercially available bisphenol-type (meth) acrylate compounds include, for example, 2,2-bis (4- (methacryloxydiethoxy) phenyl) propane ("BPE-200" manufactured by Shin-Nakamura Chemical Industry Co., Ltd. " ), 2,2-Bis (4- (methacryloxypentethoxy) phenyl) propane ("BPE-500" manufactured by Shin Nakamura Chemical Industry Co., Ltd. or "FA-321M" manufactured by Hitachi Kasei Co., Ltd.), 2,2-Bis (4- (methacryloxypentadecaethoxy) phenyl) propane ("BPE-1300" manufactured by Shin Nakamura Chemical Industry Co., Ltd.), 2,2-bis (4- (methacryloxypolyethoxy) phenyl) propane (Kyoeisha Chemical Co., Ltd.) "BP-2EM" manufactured by (EO group: 2.6 (average value)) and the like can be mentioned.

The content of the bisphenol type (meth) acrylate compound is 1 to 50% by mass and 3 to 40% by mass with respect to the total solid content of the components (A) and (B) from the viewpoint of further improving the chemical resistance. It may be 10 to 40% by mass, 20 to 40% by mass, or 30 to 40% by mass.

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

The content of the component (B) may be 20 to 70 parts by mass, 25 to 60 parts by mass, or 30 to 50 parts by mass with respect to 100 parts by mass of the total solid content of the component (A) and the component (B). good. When the content of the component (B) is within this range, the light sensitivity and the coating film property are further improved in addition to the resolution, the adhesion and the suppressive property of resist skirt generation of the photosensitive resin composition.

((C) Photopolymerization Initiator)
The photosensitive resin composition according to the present embodiment may contain at least one (C) photopolymerization initiator (hereinafter, also referred to as “(C) component”). The component (C) is not particularly limited as long as it can polymerize the component (B), and can be appropriately selected from commonly used photopolymerization initiators.

Examples of the component (C) include 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) -butanone-1, 2-methyl-1- [4- (methylthio) phenyl] -2-morpholino-. Aromatic ketones such as propanone-1, quinones such as alkylanthraquinone, benzoin ether compounds such as benzoin alkyl ethers, benzoin compounds such as benzoin and alkylbenzoin, benzyl derivatives such as benzyldimethylketal, 2- (o-chlorophenyl)- 2,4,5-Triarylimidazole dimer such as 4,5-diphenylimidazole dimer, 2- (o-fluorophenyl) -4,5-diphenylimidazole dimer, 9-phenylacridin, 1, Examples thereof include an acridin derivative such as 7- (9,9'-acrydinyl) heptane. These can be used alone or in combination of two or more.

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

As the 2,4,5-triarylimidazole dimer, for example, 2,2'-bis (2-chlorophenyl) -4,4', 5,5'-tetraphenylbiimidazole is B-CIM (hodogaya). It is commercially available as (product name) manufactured by Hodogaya Chemical Co., Ltd.

The component (C) contains at least one of 2,4,5-triarylimidazole dimer from the viewpoint of further improving the light sensitivity and adhesion and further suppressing the light absorption of the component (C). However, it may contain 2- (2-chlorophenyl) -4,5-diphenylimidazole dimer. The structure of the 2,4,5-triarylimidazole dimer may be symmetric or asymmetric.

The content of the component (C) is 0.01 to 30 parts by mass, 0.1 to 10 parts by mass, and 1 to 7 parts by mass with respect to 100 parts by mass of the total solid content of the components (A) and (B). It may be 1 to 6 parts by mass, 1 to 5 parts by mass, or 2 to 5 parts by mass. When the content of the component (C) is 0.01 parts by mass or more, the light sensitivity, resolution and adhesion tend to be improved, and when the content is 30 parts by mass or less, the resist pattern shape tends to be excellent.

((D) Photosensitizer)
The photosensitive resin composition according to the present embodiment may contain (D) a photosensitizer (hereinafter, also referred to as “(D) component”). By containing the component (D), there is a tendency that the absorption wavelength of the active light beam used for exposure can be effectively used.

Examples of the component (D) include pyrazolines, dialkylaminobenzophenones, anthracenes, coumarins, acridines, xanthones, oxazoles, benzoxazoles, thiazoles, benzothiazoles, triazoles, stelvenes, and triazines. Species, thiophenes, naphthalimides and triarylamines. These can be used alone or in combination of two or more. From the viewpoint that the absorption wavelength of the active light used for exposure can be used more effectively, the component (D) may contain pyrazolines, anthracenes, coumarins, acridines or dialkylaminobenzophenones, among others, coumarins. , Acridines or dialkylaminobenzophenones may be included, and dialkylaminobenzophenones may be included. Examples of commercially available dialkylaminobenzophenones include "EAB" manufactured by Hodogaya Chemical Co., Ltd.

When the component (D) is contained, the content thereof is 1.0 part by mass or less, 0.5 part by mass or less, and 0. It may be 15 parts by mass or less, 0.12 parts by mass or less, or 0.10 parts by mass or less. When the content of the component (D) is 1.0 part by mass or less with respect to 100 parts by mass of the total solid content of the component (A) and the component (B), deterioration of the resist pattern shape and the resist hem generation property is suppressed. It can and tends to have better resolution. The content of the component (D) is 0.01 part by mass or more with respect to 100 parts by mass of the total solid content of the components (A) and (B) from the viewpoint that high light sensitivity and good resolution can be easily obtained. There may be.

((E) Polymerization inhibitor)
The photosensitive resin composition according to the present embodiment may contain (E) a polymerization inhibitor (hereinafter, also referred to as “(E) component”). By containing the component (E), the exposure amount required for photocuring the photosensitive resin composition tends to be adjusted to the optimum exposure amount for exposure with a projection exposure machine. Examples of the component (E) include catechol, resorcinol (resorcin), 1,4-hydroquinone, 2-methylcatechol, 3-methylcatechol, 4-methylcatechol, 2-ethylcatechol, 3-ethylcatechol, 4-ethyl. Resorcinol, 2-propyl catechol, 3-propyl catechol, 4-propyl catechol, 2-n-butyl catechol, 3-n-butyl catechol, 4-n-butyl catechol, 2-tert-butyl catechol, 3-tert-butyl Alkyl catechols such as catechol, 4-tert-butyl catechol, 3,5-di-tert-butyl catechol, 2-methylresorcinol, 4-methylresorcinol, 5-methylresorcinol (orcin), 2-ethylresorcinol, 4-ethyl Alkyl resorcinols such as resorcinol, 2-propylresorcinol, 4-propylresorcinol, 2-n-butylresorcinol, 4-n-butylresorcinol, 2-tert-butylresorcinol, 4-tert-butylresorcinol, methylhydroquinone, ethylhydroquinone, Examples thereof include alkylhydroquinones such as propylhydroquinone, tert-butylhydroquinone and 2,5-di-tert-butylhydroquinone, pyrogallolin and fluororesorcin. These can be used alone or in combination of two or more.

(Other ingredients)
The photosensitive resin composition according to the present embodiment includes dyes such as malakite green, Victoria pure blue, brilliant green and methyl violet, tribromophenyl sulfone, leuco crystal violet, diphenylamine, benzylamine and triphenyl, if necessary. Photocoloring agents such as amines, diethylaniline, and o-chloroaniline, heat coloring inhibitors, plasticizers such as p-toluenesulfonamide, pigments, fillers, defoaming agents, flame retardant agents, adhesion imparting agents, leveling agents. , Peeling accelerator, antioxidant, fragrance, imaging agent, thermal cross-linking agent, etc., 0.01 to 20 parts by mass, respectively, with respect to 100 parts by mass of the total solid content of the components (A) and (B). Can be contained. These additives may be used alone or in combination of two or more.

In addition, the photosensitive resin composition according to the present embodiment contains at least one organic solvent, if necessary, in order to improve the handleability of the photosensitive composition and to adjust the viscosity and storage stability. Can include. As the organic solvent, a commonly used organic solvent can be used without particular limitation. Specific examples thereof include organic solvents such as methanol, ethanol, acetone, methyl ethyl ketone, methyl cellosolve, ethyl cellosolve, toluene, N, N-dimethylformamide, propylene glycol monomethyl ether, and mixed solvents thereof. These can be used alone or in combination of two or more.

<Protective layer>
In the photosensitive element of the present embodiment, a protective layer may be laminated on the surface of the photosensitive layer opposite to the surface in contact with the barrier layer. As the protective layer, for example, a polymer film such as polyethylene or polypropylene may be used. Further, the same polymer film as the above-mentioned support film may be used, or a different polymer film may be used.

Hereinafter, 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 will be described.

<Manufacturing method of photosensitive element>
First, for example, a water-soluble resin containing polyvinyl alcohol is mixed with water heated to 70 to 90 ° C. and an organic solvent used as necessary so that the solid content is 10 to 20% by mass. It is gradually added to a solvent and stirred for about 1 hour, and then the leveling agent is mixed and uniformly dissolved to obtain a resin composition for forming a barrier layer containing polyvinyl alcohol and the leveling agent. As used herein, the term "solid content" refers to the non-volatile content 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 volatilization in the drying step, and includes liquid, starch syrup-like and wax-like components at room temperature around 25 ° C.

Next, the resin composition for forming the barrier layer is applied onto the support film and dried to form the barrier layer. The resin composition for forming a barrier layer can be applied onto a support film by a known method such as a roll coat, a comma coat, a gravure coat, an air knife coat, a die coat, a bar coat, or a spray coat.

Further, the drying of the applied resin composition for forming a barrier layer is not particularly limited as long as at least a part 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 a later step.

Next, the photosensitive resin composition is applied onto the barrier layer of the support film on which the barrier layer is formed in the same manner as the application of the resin composition for forming the barrier layer and dried to form the photosensitive layer on the barrier layer. You may. Next, by laminating the protective layer on the photosensitive layer thus formed, a photosensitive element including a support film, a barrier layer, a photosensitive layer, and a protective layer in this order is produced. Can be done. Further, by adhering the one having the barrier layer formed on the support film and the one having the photosensitive layer formed on the protective layer, the support film, the barrier layer, the photosensitive layer, and the protective layer can be attached to each other. Photosensitive elements provided in order may be obtained.

The thickness of the photosensitive layer in the photosensitive element can be appropriately selected depending on the intended use, but the thickness after drying may be 1 μm or more, 5 μm or more, or 10 μm or more, and is 200 μm or less, 100 μm or less, 50 μm or less. , Or it may be 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 is facilitated and productivity tends to be improved. Further, 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 light sensitivity is high and the photocurability of the resist bottom is excellent, so that a resist pattern having excellent resolution and aspect ratio is formed. There is a tendency to be able to do it.

The melt viscosity of the photosensitive layer in the photosensitive element at 110 ° C. can be appropriately selected depending on the type of the substrate (base) in contact with the photosensitive layer, but after drying, at 110 ° C., 50 to 10000 Pa · s, 100 to 5000 Pa. It may be s or 200 to 1000 Pa · s. When the melt viscosity at 110 ° C. is 50 Pa · s or more, wrinkles and voids do not occur in the laminating step, and the productivity tends to be improved. Further, when the melt viscosity at 110 ° C. is 10,000 Pa · s or less, the adhesiveness with the substrate is improved in the laminating step, and there is a tendency to reduce the adhesive defect.

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 may be in the form of a roll wound around a winding core. When winding in a roll shape, the support film may be wound so as to be on the outside. Examples of the material of the winding core include plastics such as polyethylene resin, polypropylene resin, polystyrene resin, polyvinyl chloride resin or ABS resin (acrylonitrile-butadiene-styrene copolymer).

An end face separator may be installed on the end face of the roll-shaped photosensitive element roll thus obtained from the viewpoint of end face protection, and a moisture-proof end face separator may be installed from the viewpoint of edge fusion resistance. May be good. As a packing method, it may be wrapped in a black sheet having low moisture permeability.

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

[Method of forming resist pattern]
The method for forming a resist pattern according to the present embodiment is as follows: (i) Using the photosensitive element, a step of arranging a photosensitive layer, a barrier layer, and a support film on a substrate in this order from the substrate side (hereinafter, "(I) Photosensitive layer and barrier layer forming step") and (ii) A step of removing the support film and exposing the photosensitive layer with active light through the barrier layer (hereinafter, "(ii)". Also referred to as "exposure step") and (iii) a step of removing the uncured portion of the barrier layer and the photosensitive layer from the substrate (hereinafter, also referred to as "(iii) developing step"), and necessary. Other steps may be included accordingly. The resist pattern can be said to be a photocured product pattern of the photosensitive resin composition and also a relief pattern. Further, depending on the purpose, the resist pattern in the present embodiment may be used as a resist or may be used for other purposes such as a protective film.

((I) Photosensitive layer and barrier layer forming step)
In the step of forming the photosensitive layer and the barrier layer, the photosensitive layer and the barrier layer are formed on the substrate by using the photosensitive element. The substrate is not particularly limited, but usually, a circuit forming substrate provided with an insulating layer and a conductor layer formed on the insulating layer, or a die pad (lead frame substrate) such as an alloy substrate may be used. Used.

As a method of forming the photosensitive layer and the barrier layer on the substrate, for example, in the case of using a photosensitive element having a protective layer, after removing the protective layer, the photosensitive layer of the photosensitive element is heated. By crimping to the substrate, the photosensitive layer and the barrier layer can be formed on the substrate. As a result, a laminated body including the substrate, the photosensitive layer, the barrier layer, and the support film in this order can be obtained.

When the photosensitive layer and the barrier layer forming step is performed using the photosensitive element, it may be performed under reduced pressure from the viewpoint of adhesion and followability. The heating at the time of crimping may be performed at a temperature of 70 to 130 ° C., and the crimping may be performed at a pressure of 0.1 to 1.0 MPa (1 to 10 kgf / cm ² ), but these conditions are necessary. It can be selected as appropriate. If the photosensitive layer of the photosensitive element is heated to 70 to 130 ° C., it is not necessary to preheat the substrate in advance, but the substrate is preheated in order to further improve the adhesion and the followability. You can also.

((Ii) exposure step)
In the exposure step, the support film is removed and the photosensitive layer is exposed to the active light through the barrier layer. As a result, the exposed portion irradiated with the active light may be photo-cured to form a photo-cured portion (latent image), or the unexposed portion not irradiated with the active light may be photo-cured. A photo-curing portion may be formed. When the photosensitive layer and the barrier layer are formed by using the photosensitive element, the support film existing on the photosensitive layer is peeled off and then exposed. By exposing the photosensitive layer through the barrier layer, a resist pattern having excellent resolution and resist pattern shape can be formed.

As an exposure method, a known exposure method can be applied. For example, a method of irradiating an image with active light rays via a negative or positive mask pattern called artwork (mask exposure method), an LDI (Laser Direct Imaging) exposure method. Alternatively, a method of irradiating an image through a lens using an active light beam on which an image of a photomask is projected (projection exposure method) and the like can be mentioned. Above all, the projection exposure method may be used from the viewpoint of excellent resolution. That is, the photosensitive element or the like according to the present embodiment is applied to the projection exposure method. The projection exposure method can also be said to be an exposure method using activated light rays having an attenuated amount of energy.

The light source of the active light is not particularly limited as long as it is a known light source that is usually used. Such as solid-state lasers, semiconductor lasers such as gallium nitride blue-violet lasers, etc. that effectively radiate ultraviolet rays are used. Further, a photographic flood bulb, a solar lamp, or the like that effectively radiates visible light may be used. Among these, from the viewpoint of improving the resolution and alignment in a well-balanced manner, a light source capable of emitting i-line monochromatic light having an exposure wavelength of 365 nm, a light source capable of emitting h-line monochromatic light having an exposure wavelength of 405 nm, or an exposure wavelength of ihg mixed lines. A light source capable of radiating the active light of the above may be used, and among them, a light source capable of radiating i-line monochromatic light having an exposure wavelength of 365 nm may be used. Examples of the light source capable of emitting i-line monochromatic light having an exposure wavelength of 365 nm include an ultrahigh voltage mercury lamp and the like.

((Iii) development process)
In the developing step, the uncured portion of the barrier layer and the photosensitive layer is removed from the substrate. By the developing step, a resist pattern composed of a photo-cured portion in which the photosensitive layer is photo-cured is formed on the substrate. When the barrier layer is water-soluble, the barrier layer may be removed by washing with water, and then the uncured portion other than the photocured portion may be removed with a developing solution, and the barrier layer is dissolved in the developing solution. If it has a property, the barrier layer may be removed with a developing solution together with the uncured portion other than the photocured portion. Examples of the developing method include wet development.

In the case of wet development, it can be developed by a known wet development method using a developer corresponding to the photosensitive resin composition. Examples of the wet development method include a method using a dip method, a paddle method, a high-pressure spray method, brushing, slapping, scraping, rocking immersion, etc. From the viewpoint of improving resolution, the high-pressure spray method is the most suitable. Is suitable. These wet development methods may be developed individually by one type or in combination of two or more types.

The developer is appropriately selected according to the composition of the photosensitive resin composition. For example, an alkaline aqueous solution and an organic solvent developer can be mentioned.

From the viewpoint of safety, stability, and good operability, an alkaline aqueous solution may be used as the developer. Examples of the base of the alkaline aqueous solution include alkali hydroxides such as lithium, sodium or potassium hydroxides, alkali carbonates such as lithium, sodium, potassium or ammonium carbonates or bicarbonates, potassium phosphates and sodium phosphates. Alkaline metal phosphates such as, sodium pyrophosphate, alkali metal pyrophosphates such as potassium pyrophosphate, sodium borate, sodium metasilicate, tetramethylammonium hydroxide, ethanolamine, ethylenediamine, diethylenetriamine, 2-amino-2- Hydroxymethyl-1,3-propanediol, 1,3-diamino-2-propanol and morpholin are used.

Examples of the alkaline aqueous solution used for development include a dilute solution of 0.1 to 5% by mass sodium carbonate, a dilute solution of 0.1 to 5% by mass of potassium carbonate, and a dilute solution of 0.1 to 5% by mass of sodium hydroxide. A dilute solution of 0.1 to 5% by mass sodium tetraborate or the like can be used. The pH of the alkaline aqueous solution used for development may be in the range of 9 to 11, and the temperature of the alkaline aqueous solution can be adjusted according to the developability of the photosensitive layer. Further, for example, a surface active agent, a defoaming agent, a small amount of an organic solvent for accelerating development, or the like may be mixed in the alkaline aqueous solution. Examples of the organic solvent used in the alkaline aqueous solution include 3-acetone alcohol, acetone, ethyl acetate, alkoxyethanol having an alkoxy group having 1 to 4 carbon atoms, ethyl alcohol, isopropyl alcohol, butyl alcohol, diethylene glycol monomethyl ether, and the like. Examples thereof include diethylene glycol monoethyl ether and diethylene glycol monobutyl ether.

Examples of the organic solvent used in the organic solvent developer include 1,1,1-trichloroethane, N-methylpyrrolidone, N, N-dimethylformamide, cyclohexanone, methyl isobutyl ketone and γ-butyrolactone. From the viewpoint of preventing ignition, these organic solvents may be prepared as an organic solvent developer by adding water so as to be in the range of 1 to 20% by mass.

(Other processes)
In the method for forming a resist pattern according to the present embodiment, after removing the uncured portion in the developing step, heating at 60 to 250 ° C. or exposure at an exposure amount of ^{0.2 to 10 J / cm 2 is performed as necessary.} By doing so, a step of further curing the resist pattern may be included.

[Manufacturing method of printed wiring board]
The method for manufacturing a printed wiring board according to the present embodiment includes a step of etching or plating a substrate on which a resist pattern is formed by the above resist pattern forming method to form a conductor pattern, and if necessary, a resist pattern. Other steps such as a removal step may be included. The method for manufacturing a printed wiring board according to the present embodiment can be suitably used for forming a conductor pattern by using the method for forming a resist pattern using the above-mentioned photosensitive element. Among them, the conductor pattern is formed by plating. The application to the method is more suitable. The conductor pattern can also be said to be a circuit.

In the etching process, the conductor layer of the substrate not covered with the resist is removed by etching using the resist pattern formed on the substrate provided with the conductor layer as a mask to form the conductor pattern.

The etching treatment method is appropriately selected according to the conductor layer to be removed. Examples of the etching solution include a ferric chloride solution, a ferric chloride solution, an alkaline etching solution, a hydrogen peroxide-based etching solution, and the like, and the ferric chloride solution is used because the etch factor is good. It is also good.

On the other hand, in the plating process, copper or solder is plated on the conductor layer of the substrate not covered with the resist by using the resist pattern formed on the substrate provided with the conductor layer as a mask. After the plating treatment, the resist is removed by removing the resist pattern described later, and the conductor layer covered with this resist is further etched to form a conductor pattern.

The plating treatment method may be electrolytic plating treatment or electroless plating treatment, and may be electroless plating treatment. Examples of the electroless plating treatment include copper plating such as copper sulfate plating and copper pyrophosphate plating, solder plating such as high-slow solder plating, watt bath (nickel sulfate-nickel chloride) plating, and nickel plating such as nickel sulfamate plating. Gold plating such as hard gold plating and soft gold plating can be mentioned.

After the etching treatment or plating treatment, the resist pattern on the substrate is removed. The resist pattern can be removed, for example, with a stronger alkaline aqueous solution than the alkaline aqueous solution used in the development step. As the strongly alkaline aqueous solution, for example, a 1 to 10% by mass sodium hydroxide aqueous solution, a 1 to 10% by mass potassium hydroxide aqueous solution, or the like is used. Among these, 1 to 5% by mass sodium hydroxide aqueous solution or potassium hydroxide aqueous solution may be used.

Examples of the resist pattern removing method include a dipping method and a spraying method, which may be used alone or in combination.

When the resist pattern is removed after the plating treatment, a desired printed wiring board can be manufactured by further etching the conductor layer covered with the resist by the etching treatment to form the conductor pattern. The etching treatment method at this time is appropriately selected according to the conductor layer to be removed. For example, the above-mentioned etching solution can be applied.

The method for manufacturing a printed wiring board according to the present embodiment can be applied not only to the manufacture of a single-layer printed wiring board but also to the manufacture of a multilayer printed wiring board, and also to the manufacture of a printed wiring board having a small-diameter through hole. It is possible.

The method for manufacturing a printed wiring board according to the present embodiment can be suitably used for manufacturing a high-density package substrate, particularly for manufacturing a wiring board by a semi-additive method. FIG. 2 shows an example of the manufacturing process of the wiring board by the semi-additive method.

In FIG. 2A, a substrate (circuit forming substrate) in which the conductor layer 40 is formed on the insulating layer 50 is prepared. The conductor layer 40 is, for example, a copper layer. In FIG. 2B, the photosensitive layer 30 and the barrier layer 20 are formed on the conductor layer 40 of the substrate by the photosensitive layer and barrier layer forming step. In FIG. 2C, the exposure step irradiates the photosensitive layer 30 with the active light rays 80 obtained by projecting an image of a photomask onto the photosensitive layer 30 to form a photocurable portion on the photosensitive layer 30. In FIG. 2D, the resist pattern 32, which is a photocurable portion on the substrate, is formed by removing the region (including the barrier layer) other than the photocurable portion formed by the exposure step from the substrate by the developing step. To form. In FIG. 2 (e), the plating layer 60 is formed on the conductor layer 40 of the substrate which is not covered with the resist by the plating treatment using the resist pattern 32 which is the photo-curing portion as a mask. In FIG. 2 (f), the resist pattern 32, which is a photocurable portion, is peeled off with an aqueous solution of a strong alkali, and then the conductor layer 40 masked by the resist pattern 32 is removed by a flash etching process, and the plating after the etching process is performed. A conductor pattern 70 including the layer 62 and the conductor layer 42 after the etching treatment is formed. The material of the conductor layer 40 and the plating layer 60 may be the same or different. When the conductor layer 40 and the plating layer 60 are made of the same material, the conductor layer 40 and the plating layer 60 may be integrated. Although the projection exposure method has been described with reference to FIG. 2, the resist pattern 32 may be formed by using the mask exposure method and the LDI exposure method in combination.

Although the preferred embodiments of the present disclosure have been described above, the present disclosure is not limited to the above embodiments.

Hereinafter, the present disclosure will be described more specifically based on the examples, but the present disclosure is not limited to the following examples. Unless otherwise specified, "parts" and "%" are based on mass.

First, the binder polymer (A-1) was synthesized according to Synthesis Example 1.

<Synthesis example 1>
As a polymerizable monomer, 125 g of methacrylic acid, 25 g of methyl methacrylate, 125 g of benzyl methacrylate and 225 g of styrene were mixed with 1.5 g of azobisisobutyronitrile to prepare a solution a.

Further, 1.2 g of azobisisobutyronitrile was dissolved in 100 g of a mixed solution (mass ratio 3: 2) of 60 g of methyl cellosolve and 40 g of toluene to prepare a solution b.

On the other hand, a mixed solution of methyl cellosolve and toluene having a mass ratio of 3: 2 in a flask equipped with a stirrer, a reflux condenser, a thermometer, a dropping funnel and a nitrogen gas introduction tube (hereinafter, also referred to as “mixed solution x”). 400 g was added, and the mixture was stirred while blowing nitrogen gas and heated to 80 ° C.

The above solution a was added dropwise to the mixed solution x in the flask over 4 hours at a constant dropping rate, and then the mixture was stirred at 80 ° C. for 2 hours. Then, the solution b was added dropwise to the solution in the flask over 10 minutes at a constant dropping rate, and then the solution in the flask was stirred at 80 ° C. for 3 hours. Further, the solution in the flask was heated to 90 ° C. over 30 minutes, kept warm at 90 ° C. for 2 hours, and then cooled to room temperature to obtain a solution of the binder polymer (A-1). The solution of the binder polymer (A-1) was prepared by adding the mixed solution x so that the non-volatile component (solid content) was 50% by mass.

The weight average molecular weight of the binder polymer (A-1) was 50,000, and the acid value was 163 mgKOH / g. The acid value was measured by the neutralization titration method. Specifically, 30 g of acetone is added to 1 g of the solution of the binder polymer, and the mixture is further uniformly dissolved. Then, an appropriate amount of phenolphthalein, which is an indicator, is added to the solution of the binder polymer, and a 0.1 N KOH aqueous solution is added. It was measured by performing titration using. The weight average molecular weight was measured by gel permeation chromatography (GPC) and derived by conversion using a standard polystyrene calibration curve. The conditions of GPC are shown below.

-GPC conditions-
Pump: Hitachi L-6000 type (manufactured by Hitachi, Ltd.)
Columns: A total of 3 columns (column specifications: 10.7 mmφ x 300 mm, all manufactured by Hitachi Kasei Co., Ltd.)
Gelpack GL-R420
Gelpack GL-R430
Gelpack GL-R440
Eluent: Tetrahydrofuran Sample concentration: 120 mg of a binder polymer having a solid content of 50% by mass was collected and dissolved in 5 mL of tetrahydrofuran to prepare a sample.
Measurement temperature: 25 ° C
Flow rate: 2.05 mL / min Detector: Hitachi L-3300 type RI (manufactured by Hitachi, Ltd., product name)

<Preparation of resin composition for forming barrier layer>
Next, each component shown in Table 1 below was mixed in an amount (unit: parts by mass) shown in the same table to obtain a resin composition for forming a barrier layer. Specifically, the water-soluble resin was slowly added to water and alcohols at room temperature, and after the total amount was added, the mixture was heated to 90 ° C. After reaching 90 ° C., the mixture was stirred for 1 hour, then the leveling agent was mixed and uniformly dissolved, and the mixture was cooled to room temperature to obtain a resin composition for forming a barrier layer. The blending amounts other than the solvent in Table 1 are the blending amounts in terms of solid content.

<Preparation of photosensitive resin composition>
Next, each component shown in Table 1 below was mixed in an amount (unit: parts by mass) shown in the same table to obtain a photosensitive resin composition.

The details of each component in Table 1 are as follows.
(Water-soluble resin)
* 1: Polyvinyl alcohol EG-05 (manufactured by Nippon Synthetic Chemical Industry Co., Ltd., product name, saponification degree = 88 mol%)
* 2: Polyvinylpyrrolidone K-30 (manufactured by Nippon Shokubai Co., Ltd., product name)

(Leveling agent)
* 3: WS-314 (acrylic polymer, manufactured by Kyoeisha Chemical Co., Ltd., product name, component: 48% by mass of acrylic polymer and 52% by mass of 3-methoxy-3-methyl-1-butanol, composition of acrylic polymer : A copolymer of about 6.89 mol% of butyl (meth) acrylate, about 61.4 mol% of isobutyl (meth) acrylate and about 31.7 mol% of terminal methoxy group EO-modified (meth) acrylate)
* 4: F-444 (polytetrafluoroethylene, manufactured by DIC Corporation, product name)

(A) Component: Binder polymer * 5: (A-1) (Binder polymer (A-1) obtained in Synthesis Example 1)
Methacrylic acid / methyl methacrylate / benzyl methacrylate / styrene = 25/5/25/45 (mass ratio), weight average molecular weight = 50,000, solid content = 50% by mass, methyl cellosolve / toluene = 3/2 (mass ratio) )solution

(B) Component: Photopolymerizable compound having an ethylenically unsaturated bond * 6: FA-321M (manufactured by Hitachi Kasei Co., Ltd., product name)
2,2-Bis (4- (methacryloxypentethoxy) phenyl) propane * 7: FA-024M (manufactured by Hitachi Kasei Co., Ltd., product name)
EOPO modified dimethacrylate * 8: BPE-200 (manufactured by Shin Nakamura Chemical Industry Co., Ltd., product name)
2,2-Bis (4- (methacryloxydiethoxy) phenyl) propane

(C) Ingredient: Photopolymerization initiator * 9: B-CIM (manufactured by Hodogaya Chemical Co., Ltd., product name)
2,2'-bis (2-chlorophenyl) -4,4', 5,5'-tetraphenylbiimidazole

(D) Ingredient: Photosensitizer * 10: EAB (manufactured by Hodogaya Chemical Co., Ltd., product name)
4,4'-Bis (diethylamino) benzophenone

(E) Ingredient: Polymerization inhibitor * 11: TBC (manufactured by DIC Corporation)
4-tert-Butylcatechol

[Examples 1 to 4 and Comparative Example 1]
<Manufacturing of photosensitive element>
As a support film for the photosensitive element, the PET film shown in Table 1 was prepared.

The details of the PET film shown in Table 1 are as follows.
R-705G: Biaxially oriented polyester film having a two-layer structure (manufactured by Mitsubishi Chemical Corporation, product name, thickness: 16 μm) having an antistatic layer on the opposite surface on the side to which the photosensitive resin composition is applied.

(Preparation of barrier layer)
Next, the resin composition for forming a barrier layer was applied onto the PET film (supporting film) so that the thickness was uniform, and dried in a hot air convection dryer at 95 ° C. for 10 minutes, and the thickness after drying was 5 μm. A barrier layer was formed. When the lubricant densities were different on both sides of the PET film, a barrier layer was formed on the surface of the PET film having less lubricant.

(Preparation of photosensitive layer)
Next, the photosensitive resin composition was applied onto the barrier layer of the support film so that the thickness was uniform, and dried in a hot air convection dryer at 100 ° C. for 10 minutes, and the thickness after drying was 15 μm. A photosensitive layer was formed.

Next, a polyethylene protective film (protective layer) (manufactured by Tamapoli Co., Ltd., product name "NF-15A") is bonded onto this photosensitive layer, and the PET film (supporting film), the barrier layer, and the photosensitive layer are formed. , A photosensitive element in which the protective layer was laminated in this order was obtained.

<Manufacturing of laminated body>
After the copper surface of a copper-clad laminate (board, manufactured by Hitachi Kasei Co., Ltd., product name "MCL-E-67"), which is a glass epoxy material in which copper foil with a thickness of 12 μm is laminated on both sides, is treated with acid and washed with water. , Dry with air flow. The copper-clad laminate was heated to 80 ° C., and while the protective layer was peeled off, the photosensitive elements were pressure-bonded to the copper-clad laminate so that the photosensitive layer was in contact with the copper surface. The crimping was performed using a heat roll at 110 ° C. at a pressure of 0.40 MPa and a roll speed of 1.0 m / min. In this way, a laminate in which the substrate, the photosensitive layer, the barrier layer, and the support film were laminated in this order was obtained. These laminates were used as test pieces in the tests shown below. As the laminator, HLM-3000 (manufactured by Taisei Laminator Co., Ltd., product name) was used.

<Evaluation of surface defects in the barrier layer>
For the sample after the barrier layer forming resin composition was applied on the support film and dried to form the barrier layer, the number of defects on the surface of the barrier layer (defects in which the coating film was dented and the base was exposed) was determined. The measurement was performed using a surface defect inspection device "FITS-Hybrids" (manufactured by Ayaha Engineering Co., Ltd.). Maximum diameter of the MD (longitudinal) direction or TD (transverse) direction is determined a value obtained by converting the area of 1 m ² per the number of defects of size greater than 60 [mu] m.

<Measurement of peel strength>
While peeling off the protective layer on the copper-clad laminate, the photosensitive elements were pressure-bonded to the copper-clad laminate so that the photosensitive layer was in contact with the copper surface, and then cut into a width of 25 mm and a length of 150 mm. The crimping was performed using a heat roll at 110 ° C. at a pressure of 0.40 MPa and a roll speed of 1.5 m / min. The cut strength of the cut sample was measured by using a rheometer "NRM-2010J-CW" (manufactured by Fudo Kogyo Co., Ltd.) in the direction of 180 degrees at a pulling speed of 30 cm / min to measure the peel strength between the support film and the barrier layers. The measurement temperature was 23 ° C. For the peel strength, the average value of the values measured for the five samples was obtained. The lower the peel strength, the easier it is to peel between the support film and the barrier layer when the support film is peeled off, and it is possible to prevent a part of the barrier layer from adhering to the support film and being damaged.

In Examples 1 to 4 to which the leveling agent was added, the number of surface defects was reduced in all the examples as compared with Comparative Example 1. It is considered that this is an effect that the leveling agent is oriented on the surface of the coating film and the tension on the surface of the coating film is made uniform. On the other hand, the peel strength was significantly reduced in Examples 1 to 3 in which WS-314 was added. It is considered that this is because the alkyl side chain in the acrylic polymer reduced the adhesion to PET.

1 ... Photosensitive element, 2 ... Support film, 3, 20 ... Barrier layer, 4, 30 ... Photosensitive layer, 5 ... Protective layer, 32 ... Resist pattern, 40 ... Conductor layer, 42 ... Conductor layer after etching treatment, 50 ... Insulation layer, 60 ... Plating layer, 62 ... Plating layer after etching treatment, 70 ... Conductor pattern, 80 ... Active light.

Claims

A photosensitive element including a support film, a barrier layer, and a photosensitive layer in this order, wherein the barrier layer contains a leveling agent.
The leveling agent comprises a copolymer having a structural unit derived from at least one selected from the group consisting of butyl (meth) acrylate, isobutyl (meth) acrylate, and terminal methoxy group EO-modified (meth) acrylate. The photosensitive element according to claim 1.
The photosensitive element according to claim 1 or 2, wherein the barrier layer contains polyvinyl alcohol.
The photosensitive element according to any one of claims 1 to 3, wherein the barrier layer has a thickness of 2 to 12 μm.
The photosensitive element according to any one of claims 1 to 4, wherein the photosensitive layer contains a bisphenol A type di (meth) acrylate compound.
The photosensitive layer contains 2,2-bis (4-((meth) acryloxipentethoxy) phenyl) propane and / or 2,2-bis (4-((meth) acryloxidiethoxy) phenyl) propane. , The photosensitive element according to any one of claims 1 to 5.
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 the photosensitive element according to any one of claims 1 to 6.
A step of removing the support film and exposing the photosensitive layer with an active ray 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.
A method for manufacturing a printed wiring board, comprising a step of etching or plating a substrate on which a resist pattern is formed by the method for forming a resist pattern according to claim 7 to form a conductor pattern.