JP2023158423A - Photosensitive resin composition, photosensitive element, method for forming resist pattern, and method for manufacturing printed wiring board - Google Patents

Abstract

To provide a photosensitive resin composition which can shorten development time without impairing excellent resolution and adhesion.SOLUTION: A photosensitive resin composition contains (A) a binder polymer, (B) a photopolymerizable compound, and (C) a photopolymerization initiator represented by the following general formula (I), wherein (C) the photopolymerization initiator contains at least a first photopolymerization initiator which does not have an alkoxy group and is represented by the following general formula (I), and a second photopolymerization initiator which has an alkoxy group and is represented by the following general formula (I). The absorbance to light with a wavelength of 365 nm per 1 μm thickness of the photosensitive resin composition is 0.0030 to 0.0119. In the formula (I), Z1 and Z2 each independently represent a monovalent group represented by general formula (II) or (III).SELECTED DRAWING: None

Description

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

In the field of manufacturing printed wiring boards, a photosensitive resin composition and a layer containing this photosensitive resin composition (hereinafter referred to as "photosensitive layer") are used as resist materials for etching, plating, etc. on a support. A photosensitive element (laminate) having a structure in which a protective film is disposed on a photosensitive layer is widely used.

When manufacturing a printed wiring board using a photosensitive element, first, a photosensitive layer of the photosensitive element is laminated onto a circuit forming substrate. Next, a predetermined portion of the photosensitive layer is irradiated with actinic light to cure the exposed portion. Thereafter, after peeling off the support, a resist pattern is formed on the substrate by removing the unexposed portion of the photosensitive layer with a developer. Next, using this resist pattern as a mask, the substrate on which the resist pattern has been formed is subjected to etching or plating to form a circuit pattern on the substrate, and finally the cured portion of the photosensitive layer (resist pattern) is peeled off from the substrate. Remove.

As for the exposure method, the photosensitive layer is exposed in a pattern through a mask film or the like. In recent years, a projection exposure method has been used in which a photosensitive layer is exposed to light by irradiating the active light beam onto which an image of a photomask is projected through a lens. An ultra-high pressure mercury lamp is used as a light source for projection exposure. Generally, exposure machines that use I-line monochromatic light (365 nm) as the exposure wavelength are often used, but H-line monochromatic light (405 nm) and IHG crosstalk exposure wavelengths may also be used.

The projection exposure method is an exposure method that can ensure higher resolution and higher alignment than the contact exposure method. Therefore, in these days when there is a demand for miniaturization of circuit formation on printed wiring boards, the projection exposure method is attracting a lot of attention.

With the recent increase in the density of printed wiring boards, there is an increasing demand for photosensitive resin compositions with excellent resolution and adhesion. In particular, in manufacturing a package substrate, there is a need for a photosensitive resin composition that can form a resist pattern with a line width/space width of 10/10 (unit: μm) or less. For example, Patent Document 1 considers improving resolution and adhesion by using a specific photopolymerizable compound.

Japanese Patent Application Publication No. 2013-195712

However, photosensitive resin compositions with excellent resolution and adhesion have a problem in that the developing time of the photosensitive layer tends to be long. It is desirable to shorten the development time as much as possible in order to improve production throughput.

Therefore, the present disclosure provides a photosensitive resin composition, a photosensitive element, a method for forming a resist pattern, and a method for manufacturing a printed wiring board, which can shorten development time without impairing excellent resolution and adhesion. The purpose is to

In order to solve the above problems, the present inventors conducted intensive studies focusing on photopolymerization initiators. As a result, by using two or more specific photopolymerization initiators in combination and keeping the absorbance within a specific range, we have developed a photosensitive material that is sufficiently effective in shortening development time without sacrificing excellent resolution and adhesion. The present inventors have discovered that it is possible to obtain a synthetic resin composition, and have completed the present invention. That is, the present invention provides the following photosensitive resin composition, photosensitive element, resist pattern forming method, and printed wiring board manufacturing method.

[1] A photosensitive resin composition containing (A) a binder polymer, (B) a photopolymerizable compound, and (C) a photopolymerization initiator represented by the following general formula (I), C) The photopolymerization initiator is a first photopolymerization initiator represented by the following general formula (I) that does not have an alkoxy group, and a second photopolymerization initiator represented by the following general formula (I) that has an alkoxy group. A photosensitive resin composition, which comprises at least a photopolymerization initiator, and has an absorbance of 0.0030 to 0.0119 for light with a wavelength of 365 nm per 1 μm of thickness.

[In formula (I), Z ¹ and Z ² each independently represent a monovalent group represented by the following general formula (II) or (III). ]


[In formula (II) and formula (III), R ¹ to R ³⁰ each independently represent a hydrogen atom, a halogen atom, or an alkoxy group having 1 to 5 carbon atoms, and a plurality of R ¹ to R ³⁰ in the same molecule When present, they may be the same or different. ]
[2] The photosensitive resin composition according to [1] above, wherein the second photoinitiator has at least one methoxy group.
[3] The photosensitive resin according to [1] or [2] above, wherein the content of the photopolymerization initiator (C) is 1 to 5% by mass based on the total solid content of the photosensitive resin composition. Composition.
[4] The photosensitive resin composition according to any one of [1] to [3] above, wherein the binder polymer (A) contains a binder polymer having a divalent group represented by the following general formula (IV). thing.

[In formula (IV), R ³¹ represents a hydrogen atom or a methyl group, R ³² represents a hydrogen atom, an alkyl group having 1 to 3 carbon atoms, an alkoxy group having 1 to 3 carbon atoms, a hydroxyl group, or a halogen atom, R ³² may be the same or different. ]
[5] The photosensitive resin composition according to any one of [1] to [4] above, wherein the binder polymer (A) contains a binder polymer having a divalent group represented by the following general formula (V). thing.

[In formula (V), R ³³ represents a hydrogen atom or a methyl group. ]
[6] The photosensitive resin composition according to any one of [1] to [5] above, wherein the binder polymer (A) contains a binder polymer having a divalent group represented by the following general formula (VI). thing.

[In formula (VI), R ³⁴ represents a hydrogen atom or a methyl group, R ³⁵ represents an alkyl group having 1 to 3 carbon atoms, an alkoxy group having 1 to 3 carbon atoms, a hydroxyl group or a halogen atom, and m is 0 to represents an integer of 5, and multiple R ^35s may be the same or different from each other. ]
[7] The photosensitive resin composition according to any one of [1] to [6] above, wherein the binder polymer (A) contains a binder polymer having a divalent group represented by the following general formula (VII). thing.

[In formula (VII), R ³⁶ represents a hydrogen atom or a methyl group, R ³⁷ represents an alkyl group having 1 to 3 carbon atoms, an alkoxy group having 1 to 3 carbon atoms, a hydroxyl group, or a halogen atom, and n is 0 to represents an integer of 5, and multiple R ^37s may be the same or different from each other. ]
[8] The photosensitive resin composition according to any one of [1] to [7] above, wherein the binder polymer (A) contains a binder polymer having a weight average molecular weight of 20,000 to 50,000.
[9] The photosensitive resin composition according to any one of [1] to [8] above, which further contains a heterocyclic compound.
[10] The photosensitive resin composition according to any one of [1] to [9] above, which further contains a hydrogen-donating compound.
[11] The photosensitive resin composition according to any one of [1] to [10] above, further containing a polymerization inhibitor.
[12] The photosensitive resin composition according to any one of [1] to [11] above, further containing a dye.
[13] The photosensitive resin composition according to any one of [1] to [12] above, wherein the content of the sensitizer is 0.065% by mass or less based on the total solid content of the photosensitive resin composition. thing.
[14] A photosensitive element comprising a support and a photosensitive layer containing the photosensitive resin composition according to any one of [1] to [13] above, formed on the support.
[15] A photosensitive layer comprising a photosensitive layer comprising the photosensitive resin composition according to any one of [1] to [13] above, or a photosensitive layer of the photosensitive element according to [14] above, which is laminated on a substrate. a forming step, an exposure step of irradiating a predetermined portion of the photosensitive layer with actinic rays to form a photocured portion, and a developing step of removing a region of the photosensitive layer other than the predetermined portion from the substrate. How to form a resist pattern.
[16] The method for forming a resist pattern according to the above [15], wherein the wavelength of the actinic light is within the range of 340 to 430 nm.
[17] Manufacture of a printed wiring board, including the step of etching or plating a substrate on which a resist pattern is formed by the resist pattern forming method described in [15] or [16] above to form a conductor pattern. Method.

The photosensitive resin composition described in [1] above is configured by combining the specific components as described above, so that it can form a resist pattern with sufficient resolution and adhesion even when forming a resist pattern by a projection exposure method. can be formed, and the development time can also be sufficiently shortened. Furthermore, by adjusting the absorbance of the photosensitive resin composition to 0.0030 or more for light having a wavelength of 365 nm per 1 μm of thickness, it is possible to suppress a decrease in resolution. Furthermore, resolution and adhesion are improved by adjusting the absorbance of the photosensitive resin composition to 0.0119 or less for light with a wavelength of 365 nm per 1 μm of thickness. Furthermore, the present inventors believe that by combining two or more specific initiators such as component (C) above, it was possible to shorten the development time of the photosensitive layer without reducing resolution and adhesion. ing. Moreover, according to the photosensitive resin composition, the time required to peel off a resist pattern can also be shortened.

According to the photosensitive resin composition described in [2] above, the adhesion of the photosensitive resin composition can be further improved, and the development time and peeling time can be further shortened.

In the photosensitive resin composition described in [3] above, when the content of the photopolymerization initiator (C) is 1% by mass or more, the resolution and adhesion of the photosensitive resin composition are further improved. Furthermore, when the content of the photopolymerization initiator (C) is 5% by mass or less, the development time and peeling time can be further shortened. In addition, since the content of (C) photopolymerization initiator is within the above range, the bending resistance obtained using a cylindrical mandrel with a diameter of 6 μm according to the cylindrical mandrel method (JIS K5600-5-1:1999) can be improved. In the test, it is possible to suppress the occurrence of cracks in the photosensitive layer after exposure.

According to the photosensitive resin composition described in [4] above, the resolution and adhesion of the photosensitive resin composition are further improved.

According to the photosensitive resin composition described in [5] above, the resolution and adhesion of the photosensitive resin composition are further improved. Furthermore, the development time and peeling time can be further shortened.

According to the photosensitive resin composition described in [6] above, the resolution and adhesion of the photosensitive resin composition are further improved.

According to the photosensitive resin composition described in [7] above, the resolution and adhesion of the photosensitive resin composition are further improved. Furthermore, the development time and peeling time can be further shortened.

According to the photosensitive resin composition described in [8] above, the resolution and adhesion of the photosensitive resin composition can be further improved, and the development time and peeling time can be further shortened.

According to the photosensitive resin composition described in [9] above, the adhesion of the photosensitive resin composition is further improved.

According to the photosensitive resin composition described in [10] above, the sensitivity, resolution, and adhesion of the photosensitive resin composition are further improved.

According to the photosensitive resin composition described in [11] above, resolution and stability are improved because unintended curing reactions in areas other than exposed areas of the photosensitive layer can be suppressed.

According to the photosensitive resin composition described in [12] above, the adhesion of the photosensitive resin composition can be further improved, and the development time and peeling time can be further shortened.

According to the photosensitive resin composition described in [13] above, the absorbance of the photosensitive resin composition for light with a wavelength of 365 nm does not become too high, and resolution and adhesion are further improved.

According to the photosensitive element described in [14] above, since it is provided with a photosensitive layer containing the photosensitive resin composition, sufficient resolution and adhesion can be achieved even when forming a resist pattern by exposure using a projection exposure method. It is possible to form a resist pattern with high accuracy, and it is also effective in shortening the development time and peeling time.

According to the method for forming a resist pattern described in [15] above, a resist pattern is formed using a photosensitive layer containing the photosensitive resin composition, so a resist pattern with sufficient resolution and adhesion is formed. can do.

In the exposure wavelength range defined by the resist pattern forming method described in [16] above, the curing reaction of the photosensitive resin composition proceeds efficiently. Therefore, according to the resist pattern forming method described in [16] above, a resist pattern with more sufficient resolution and adhesion can be formed.

According to the method for manufacturing a printed wiring board described in [17] above, since a circuit forming substrate on which a resist pattern is formed by the above resist pattern forming method is used, it is possible to form high-density wiring, and it is also possible to By shortening the time and peeling time, production with high throughput is possible.

According to the present disclosure, there are provided a photosensitive resin composition, a photosensitive element, a method for forming a resist pattern, and a method for manufacturing a printed wiring board, which can shorten development time without impairing excellent resolution and adhesion. be able to.

Embodiments of the present disclosure will be described in detail below. However, the present disclosure is not limited to the following embodiments.

In this specification, the term "process" is used not only to refer to an independent process, but also to include any process that achieves the intended effect even if it cannot be clearly distinguished from other processes. It will be done. In this specification, the term "layer" includes not only a structure formed on the entire surface but also a structure formed on a part of the layer when observed in a plan view. 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.

In this specification, a numerical range indicated using "~" indicates a range that includes the numerical values written before and after "~" as the minimum and maximum values, respectively. In the numerical ranges described stepwise in this specification, the upper limit or lower limit of the numerical range of one step may be replaced with the upper limit or lower limit of the numerical range of another step. Further, in the numerical ranges described in this specification, the upper limit or lower limit of the numerical range may be replaced with the value shown in the Examples.

When referring to the amount of each component in the composition herein, if there are multiple substances corresponding to each component in the composition, unless otherwise specified, those multiple substances present in the composition means the total amount of

[Photosensitive resin composition]
The photosensitive resin composition of the present embodiment includes (A) component: binder polymer, (B) component: photopolymerizable compound, and (C) component: photopolymerization initiator represented by the following general formula (I). Contains. The above component (C) consists of a first photopolymerization initiator represented by the following general formula (I) that does not have an alkoxy group, and a second photopolymerization initiator represented by the following general formula (I) that has an alkoxy group. It contains at least a polymerization initiator. The photosensitive resin composition has an absorbance of 0.0030 to 0.0119 for light with a wavelength of 365 nm per 1 μm of thickness.

[In formula (I), Z ¹ and Z ² each independently represent a monovalent group represented by the following general formula (II) or (III). ]


[In formula (II) and formula (III), R ¹ to R ³⁰ each independently represent a hydrogen atom, a halogen atom, or an alkoxy group having 1 to 5 carbon atoms, and a plurality of R ¹ to R ³⁰ in the same molecule When present, they may be the same or different. ]

The photosensitive resin composition of this embodiment contains the above-mentioned components (A) to (C) as essential components, and has an absorbance of 0.0030 to 0.0119 for light with a wavelength of 365 nm per 1 μm of thickness. , a resist pattern with excellent resolution and adhesion can be formed, and the development time of the photosensitive layer can be shortened. Moreover, according to the photosensitive resin composition of this embodiment, the time required to peel off a resist pattern can also be shortened.

The photosensitive resin composition of this embodiment may further contain a hydrogen donor or other components as necessary. Each component used in the photosensitive resin composition of this embodiment will be explained in more detail below.

((A) component: binder polymer)
The photosensitive resin composition of this embodiment can further improve resolution and adhesion by containing a binder polymer.

Component (A) is a divalent group represented by the following general formula (IV), a divalent group represented by the following general formula (V), and a divalent group represented by the following general formula (VI). , and a binder polymer having at least one type of divalent group represented by the following general formula (VII). This further improves the resolution and adhesion of the photosensitive resin composition. Furthermore, the development time and peeling time can be further shortened.

In formula (IV), R ³¹ represents a hydrogen atom or a methyl group, R ³² represents a hydrogen atom, an alkyl group having 1 to 3 carbon atoms, an alkoxy group having 1 to 3 carbon atoms, a hydroxyl group, or a halogen atom, R ³² may be the same or different.

In formula (V), R ³³ represents a hydrogen atom or a methyl group.

In formula (VI), R ³⁴ represents a hydrogen atom or a methyl group, R ³⁵ represents an alkyl group having 1 to 3 carbon atoms, an alkoxy group having 1 to 3 carbon atoms, a hydroxyl group or a halogen atom, and m is 0 to 5 represents an integer, and multiple R ^35s may be the same or different from each other.

In formula (VII), R ³⁶ represents a hydrogen atom or a methyl group, R ³⁷ represents an alkyl group having 1 to 3 carbon atoms, an alkoxy group having 1 to 3 carbon atoms, a hydroxyl group, or a halogen atom, and n is 0 to 5 represents an integer, and multiple R ^37s may be the same or different from each other.

The weight average molecular weight (Mw) of component (A) may be 8,000 to 100,000, 10,000 to 80,000, 15,000 to 70,000, or 20,000 to 50,000. When Mw is 100,000 or less, resolution and developability tend to improve, and when Mw is 8,000 or more, the flexibility of the cured film improves, making it difficult for the resist pattern to chip or peel. There is a tendency. The dispersity (Mw/Mn) of component (A) may be 1.0 to 3.0, 1.2 to 2.5, 1.4 to 2.3, or 1.5 to 2.0. . As the degree of dispersion decreases, resolution tends to improve. The weight average molecular weight of the binder polymer is measured by gel permeation chromatography (GPC) (converted using a calibration curve using standard polystyrene).

In the photosensitive resin composition of this embodiment, as the component (A), one type of binder polymer may be used alone, or two or more types of binder polymers may be used in any combination. Examples of binder polymers when two or more types are used in combination include two or more binder polymers (containing different monomer units as copolymer components) consisting of different copolymerization components, and two or more binder polymers with different Mws. can be mentioned.

The acid value of component (A) may be 100 to 250 mgKOH/g, 120 to 240 mgKOH/g, 140 to 230 mgKOH/g, or 150 to 230 mgKOH/g. When the acid value of component (A) is 100 mgKOH/g or more, it is possible to sufficiently suppress the development time from becoming long, and when it is 250 mgKOH/g or less, the cured product of the photosensitive resin composition is resistant to developer. It becomes easier to improve the properties (adhesion).

The acid value of component (A) can be measured as follows. First, 1 g of the binder polymer whose acid value is to be measured is precisely weighed. Add 30 g of acetone to the precisely weighed binder polymer and uniformly dissolve it. Next, an appropriate amount of phenolphthalein as an indicator is added to the solution, and titration is performed using a 0.1N aqueous potassium hydroxide (KOH) solution. The acid value is determined by calculating the number of mg of KOH required to neutralize the acetone solution of the binder polymer to be measured. When measuring a solution in which a binder polymer is mixed with a synthetic solvent, a diluent solvent, etc., the acid value is calculated using the following formula.
Acid value = 0.1 x Vf x 56.1/(Wp x I/100)
In the formula, Vf indicates the titer (mL) of the KOH aqueous solution, Wp indicates the mass (g) of the solution containing the measured binder polymer, and I indicates the proportion of nonvolatile content in the solution containing the measured binder polymer. (% by mass).
In addition, when blending the binder polymer with volatile components such as synthetic solvents and diluting solvents, heat for 1 to 4 hours at a temperature 10°C or more higher than the boiling point of the volatile components before precision weighing to evaporate the volatile components. The acid value can also be measured after removing the components.

The content of component (A) in the photosensitive resin composition of the present embodiment is 20 to 90% by mass, 30 to 80% by mass, or 40 to 65% by mass based on the total solid content of the photosensitive resin composition. It may be. When the content of component (A) is 20% by mass or more, the film tends to have excellent moldability, and when it is 90% by mass or less, sensitivity and resolution tend to be excellent.

((B) component: photopolymerizable compound)
Component (B) is not particularly limited as long as it is a photopolymerizable compound that has at least one ethylenically unsaturated bond. Component (B) preferably contains at least one type of bisphenol-type (meth)acrylate from the viewpoint of improving alkali developability, resolution, and peeling characteristics after curing. Among them, it is more preferable to include bisphenol A type (meth)acrylate. Examples of bisphenol A type (meth)acrylates include 2,2-bis(4-((meth)acryloxypolyethoxy)phenyl)propane, 2,2-bis(4-((meth)acryloxypolypropoxy)) phenyl)propane, 2,2-bis(4-((meth)acryloxypolybutoxy)phenyl)propane, and 2,2-bis(4-((meth)acryloxypolyethoxypolypropoxy)phenyl)propane. It will be done. Among these, 2,2-bis(4-((meth)acryloxypolyethoxy)phenyl)propane is preferred from the viewpoint of further improving resolution and peeling characteristics.

Commercially available bisphenol A type (meth)acrylates include BPE-200 (Shin Nakamura Chemical Co., Ltd.) as 2,2-bis(4-((meth)acryloxydipropoxy)phenyl)propane. ), ethoxylated bisphenol A dimethacrylate, BP-2EM (Kyoeisha Chemical Co., Ltd., trade name), 2,2-bis(4-(methacryloxypentaethoxy)phenyl)propane, BPE -500 (manufactured by Shin-Nakamura Chemical Industry Co., Ltd., trade name) and FA-321M (manufactured by Showa Denko Materials Co., Ltd., trade name). These bisphenol A type (meth)acrylates may be used alone or in combination of two or more.

The content of bisphenol type (meth)acrylate may be 40 to 98% by mass, 50 to 97% by mass, 60 to 95% by mass, or 70 to 90% by mass, based on the total amount of component (B). When this content is 40% by mass or more, resolution, adhesion, and ability to suppress the occurrence of resist streaks will be better, and when this content is 98% by mass or less, the development time will be appropriately shortened, and the development The rest are less likely to occur.

As component (B) other than bisphenol type (meth)acrylate, from the viewpoint of improving the flexibility of the cured product (cured film), at least one of a (poly)oxyethylene chain and a (poly)oxypropylene chain is used in the molecule. The polyalkylene glycol di(meth)acrylate may further contain at least one polyalkylene glycol di(meth)acrylate having both a (poly)oxyethylene chain and a (poly)oxypropylene chain in the molecule. It may further include. Examples of the polyalkylene glycol di(meth)acrylate include FA-023M (trade name, manufactured by Showa Denko Materials Co., Ltd.), FA-024M (trade name, manufactured by Showa Denko Materials Co., Ltd.), and NK Ester HEMA-9P (manufactured by Shin-Nakamura Chemical Co., Ltd., trade name) is mentioned. These may be used alone or in combination of two or more.

The content of polyalkylene glycol di(meth)acrylate may be 2 to 40% by weight, 3 to 30% by weight, or 5 to 20% by weight based on the total amount of component (B).

As the component (B) other than the above, nonylphenoxy polyethylene oxyacrylate, phthalic acid compounds, (meth)acrylic acid polyol esters, (meth)acrylic acid alkyl esters, etc. may be used. Among them, from the viewpoint of improving resolution, adhesion, resist shape, and peeling characteristics after curing in a well-balanced manner, component (B) contains at least one selected from nonylphenoxy polyethylene oxyacrylate and phthalic acid compounds. good. However, since the refractive index of these compounds is relatively low, from the viewpoint of improving resolution, the content thereof is 5 to 50% by mass, 5 to 40% by mass, based on the total amount of component (B). Or it may be 10 to 30% by mass.

Examples of nonylphenoxypolyethyleneoxyacrylate include nonylphenoxytriethyleneoxyacrylate, nonylphenoxytetraethyleneoxyacrylate, nonylphenoxypentaethyleneoxyacrylate, nonylphenoxyhexaethyleneoxyacrylate, nonylphenoxyheptaethyleneoxyacrylate, and nonylphenoxyoctaethyleneoxyacrylate. acrylate, nonylphenoxynonaethyleneoxyacrylate, nonylphenoxydecaethyleneoxyacrylate, and nonylphenoxyundecaethyleneoxyacrylate.

Examples of phthalic acid compounds include γ-chloro-β-hydroxypropyl-β'-(meth)acryloyloxyethyl-o-phthalate and β-hydroxyethyl-β'-(meth)acryloyloxyethyl-o-phthalate. , and β-hydroxypropyl-β'-(meth)acryloyloxyethyl-o-phthalate, among which γ-chloro-β-hydroxypropyl-β'-(meth)acryloyloxyethyl-o-phthalate. It's okay. γ-Chloro-β-hydroxypropyl-β'-methacryloyloxyethyl-o-phthalate is commercially available as FA-MECH (manufactured by Showa Denko Materials Co., Ltd., trade name).

From the viewpoint of improving sensitivity and reducing trailing, component (B) may contain a (meth)acrylic acid polyol. Examples of the (meth)acrylic acid polyol ester include trimethylolpropane polyethoxy tri(meth)acrylate, trimethylolpropane polypropoxy tri(meth)acrylate, trimethylolpropane polybutoxytri(meth)acrylate, and trimethylolpropane polyethoxy Polypropoxy tri(meth)acrylate, Trimethylolethane polyethoxy tri(meth)acrylate, Trimethylolethane polypropoxy tri(meth)acrylate, Trimethylolethane polybutoxy tri(meth)acrylate, Trimethylolethane polyethoxy polypropoxy tri( meth)acrylate, pentaerythritol polyethoxytri(meth)acrylate, pentaerythritol polypropoxytri(meth)acrylate, pentaerythritol polybutoxytri(meth)acrylate, pentaerythritol polyethoxypolypropoxytri(meth)acrylate, glyceryl polyethoxytri (meth)acrylate, glyceryl polypropoxy tri(meth)acrylate, glyceryl polybutoxy tri(meth)acrylate, and glyceryl polyethoxypolypropoxy tri(meth)acrylate.

The content of component (B) is preferably 20 to 60 parts by mass, more preferably 30 to 55 parts by mass, based on 100 parts by mass of the total amount of components (A) and (B). More preferably, the amount is 35 to 50 parts by mass. When the content of component (B) is within this range, the photosensitive resin composition will have better resolution, adhesion, and resistance to resist streaks, as well as better photosensitivity and coating properties.

((C) component: photopolymerization initiator)
As component (C), two or more types of hexaarylbiimidazole derivatives represented by the following general formula (I) are used.

[In formula (I), Z ¹ and Z ² each independently represent a monovalent group represented by the following general formula (II) or (III). ]


[In formula (II) and formula (III), R ¹ to R ³⁰ each independently represent a hydrogen atom, a halogen atom, or an alkoxy group having 1 to 5 carbon atoms, and a plurality of R ¹ to R ³⁰ in the same molecule When present, they may be the same or different. ]

Examples of the hexaarylbiimidazole derivative represented by the above general formula (I) include 2-(o-chlorophenyl)-4,5-diphenylbiimidazole, 2,2',4-tris-(o-chlorophenyl) -5-(3,4-dimethoxyphenyl)-4',5'-diphenylbiimidazole, 2,4-bis-(o-chlorophenyl)-5-(3,4-dimethoxyphenyl)-diphenylbiimidazole, 2 , 4,5-tris-(o-chlorophenyl)-diphenylbiimidazole, 2-(o-chlorophenyl)-bis-4,5-(3,4-dimethoxyphenyl)-biimidazole, 2,2'-bis- (2-fluorophenyl)-4,4',5,5'-tetrakis-(3-methoxyphenyl)-biimidazole, 2,2'-bis-(2,3-difluoromethylphenyl)-4,4' , 5,5'-tetrakis-(3-methoxyphenyl)-biimidazole, 2,2'-bis-(2,4-difluorophenyl)-4,4',5,5'-tetrakis-(3-methoxy phenyl)-biimidazole, and 2,2'-bis-(2,5-difluorophenyl)-4,4',5,5'-tetrakis-(3-methoxyphenyl)-biimidazole. Among them, from the viewpoint of resolution and adhesion, 2-(o-chlorophenyl)-4,5-diphenylbiimidazole, 2,2',5-tris-(o-chlorophenyl)-4-(3,4-dimethoxyphenyl) )-4',5'-diphenylbiimidazole and 2,4-bis-(o-chlorophenyl)-5-(3,4-dimethoxyphenyl)-diphenylbiimidazole are preferred. In addition, from the viewpoint of shortening the development time and peeling time, 2,2',5-tris-(o-chlorophenyl)-4-(3,4-dimethoxyphenyl)-4',5'-diphenylbiimidazole, 2 ,4-bis-(o-chlorophenyl)-5-(3,4-dimethoxyphenyl)-diphenylbiimidazole is more preferred. 2-(o-chlorophenyl)-4,5-diphenylbiimidazole is 2,2',5-tris-(o-chlorophenyl)-4 under the trade name "B-CIM" manufactured by Hodogaya Chemical Industry Co., Ltd. -(3,4-dimethoxyphenyl)-4',5'-diphenylbiimidazole is commercially available under the trade name "TR-HABI-102" manufactured by Changzhou Strong Electronics New Materials Co., Ltd.

Component (C) has no alkoxy group (that is, none of R ¹ to R ³⁰ are alkoxy groups having 1 to 5 carbon atoms), and is a first photopolymerization initiator represented by the above general formula (I). and a second photopolymerization initiator represented by the above general formula (I) having an alkoxy group (that is, at least one of R ¹ to R ³⁰ is an alkoxy group having 1 to 5 carbon atoms). include. By using these two types of photoinitiators together, the photosensitive resin composition can shorten the development time of the photosensitive layer and the peeling time of the resist pattern without impairing excellent resolution and adhesion.

The second photopolymerization initiator may have at least one methoxy group as the alkoxy group from the viewpoint of improving resolution and adhesion. The number of alkoxy groups possessed by the second photoinitiator is 1 or more, but from the viewpoint of shortening development time and peeling time, it may be 2 or more, or 3 or more, thereby suppressing a decrease in resolution and adhesion. From this point of view, it may be 5 or less.

The first photopolymerization initiator and the second photopolymerization initiator may have at least one halogen atom from the viewpoint of improving resolution and adhesion. The number of halogen atoms contained in the first photoinitiator and the second photoinitiator may be 1 or more, 2 or more, or 3 or more from the viewpoint of improving resolution and adhesion. From the viewpoint of suppressing extension of peeling time, it may be 4 or less.

The first photopolymerization initiator may be used alone or in combination of two or more types, and the second photopolymerization initiator may be used alone or in combination of two or more types.

The content of component (C) is 0.5 to 10 parts by mass, 1 to 8 parts by mass, or 1.5 to 5 parts by mass based on 100 parts by mass of the total amount of components (A) and (B). It's good. When the content of component (C) is within this range, it becomes easy to improve both photosensitivity and resolution in a well-balanced manner. Further, when the content of component (C) is 1% by mass or more of the photosensitive resin composition, resolution and adhesion can be improved, and the content is 5% by mass or less of the photosensitive resin composition. In this case, the development time and peeling time can be sufficiently shortened. In addition, by adjusting the content of component (C) so that the absorbance for light with a wavelength of 365 nm per 1 μm of the thickness of the photosensitive resin composition is 0.0030 or more, deterioration in resolution can be suppressed. The resolution and adhesion can be improved by making the photosensitive resin composition's resistance to light with a wavelength of 365 nm per 1 μm of thickness to be 0.0119 or less.

In the component (C), the content of the first photopolymerization initiator and the second photopolymerization initiator is such that the absorbance for light with a wavelength of 365 nm per 1 μm of the thickness of the photosensitive resin composition is 0.0030 or more and 0.0030 or more. There is no particular restriction as long as it is adjusted to 0119 or less, but the component (C) Based on the total solid content (total amount of the first photoinitiator and the second photoinitiator), the content of the first photoinitiator is 40 to 97% by mass, 50 to 95% by mass, Alternatively, it may be 60 to 93% by mass.

The photosensitive resin composition of the present embodiment includes a photopolymerization initiator other than the above component (C), that is, a photopolymerization initiator represented by the above general formula (I), within a range that satisfies the above absorbance condition. It may also contain other photopolymerization initiators. The content of the other photoinitiator may be 0 to 0.5 parts by mass, or 0 to 0.1 parts by mass, based on 100 parts by mass of the total amount of components (A) and (B). It's fine.

(sensitizer)
In the photosensitive resin composition of this embodiment, the content of the sensitizer can be reduced by using the component (C). By reducing the content of the sensitizer, the development time of the photosensitive layer and the peeling time of the resist pattern can be further shortened. From this point of view, the content of the sensitizer in the photosensitive resin composition is 0.065% by mass or less, 0.030% by mass or less, or 0% by mass based on the total solid content of the photosensitive resin composition. It may be.

Examples of the sensitizer include dialkylaminobenzophenone compounds, pyrazoline compounds, anthracene compounds, coumarin compounds, xanthone compounds, stilbene compounds, and triarylamine compounds.

Examples of pyrazoline compounds include 1-phenyl-3-(4-methoxystyryl)-5-(4-methoxyphenyl)pyrazoline, 1-phenyl-3-(4-tert-butylstyryl)-5-(4- tert-butylphenyl)pyrazoline, and 1-phenyl-3-biphenyl-5-(4-tert-butylphenyl)pyrazoline. Examples of anthracene compounds include 9,10-dibutoxyanthracene and 9,10-diphenylanthracene. Coumarin compounds include, for example, 3-benzoyl-7-diethylaminocoumarin, 7-diethylamino-4-methylcoumarin, 3,3'-carbonylbis(7-diethylaminocoumarin), and 2,3,6,7-tetrahydro- Examples include 9-methyl-1H, 5H,11H-[1]benzopyrano[6,7,8-ij]chirolidin-11-one.

(heterocyclic compound)
The photosensitive resin composition of this embodiment may further contain a heterocyclic compound. Thereby, the resolution and adhesion of the photosensitive resin composition can be further improved. Examples of the heterocyclic compound include 5-carboxybenzotriazole and 5-amino-1H-tetrazole. These may be used alone or in combination of two or more.

When the photosensitive resin composition contains a heterocyclic compound, its content is 0.01 to 5.0% by mass, 0.03 to 3.0% by mass based on the total solid content of the photosensitive resin composition. % or 0.1 to 1.5% by mass. When the content of the heterocyclic compound is 0.01% by mass or more, resolution and adhesion tend to be further improved, and when it is 5.0% by mass or less, the development time and peeling time of the photosensitive layer are shortened. There is a tendency to do so.

(hydrogen donor)
The photosensitive resin composition of this embodiment may further contain a hydrogen donor (hydrogen-donating compound). This further improves the sensitivity, resolution, and adhesion of the photosensitive resin composition. Examples of hydrogen donors include bis[4-(dimethylamino)phenyl]methane, bis[4-(diethylamino)phenyl]methane, N-phenylglycine, and leucocrystal violet. These may be used alone or in combination of two or more.

When the photosensitive resin composition contains a hydrogen donor, its content is 0.01 to 10% by mass, 0.05 to 5% by mass, or 0.01 to 10% by mass, based on the total solid content of the photosensitive resin composition. It may be 1 to 2% by mass. When the content of the hydrogen donor is 0.01% by mass or more, the sensitivity can be further improved, and when the content is 10% by mass or less, excessive hydrogen donor can be prevented from precipitating as foreign matter after film formation. suppressed.

(Polymerization inhibitor)
The photosensitive resin composition of this embodiment may further contain a polymerization inhibitor. This improves the resolution of the photosensitive resin composition. Furthermore, the temperature stability of the film is improved. Examples of the polymerization inhibitor include tert-butylcatechol and 2,2,6,6-tetramethyl-4-hydroxypiperidine-1-oxyl. These may be used alone or in combination of two or more.

When the photosensitive resin composition contains a polymerization inhibitor, the content thereof is 0.001 to 1.0% by mass, 0.005 to 0.5% by mass, based on the total solid content of the photosensitive resin composition. , or 0.01 to 0.1% by mass. When the content of the polymerization inhibitor is 0.001% by mass or more, resolution can be further improved, and when it is 1.0% by mass or less, sensitivity can be further improved.

(dye)
The photosensitive resin composition of this embodiment may further contain a dye. Thereby, the adhesion of the photosensitive resin composition becomes even better, and the development time and peeling time can be shortened. Examples of the dye include malachite green and diamond green. These may be used alone or in combination of two or more.

When the photosensitive resin composition contains a dye, the content is 0.001 to 1.0% by mass, 0.005 to 0.5% by mass, or 0.005 to 0.5% by mass, based on the total solid content of the photosensitive resin composition. , 0.01 to 0.1% by mass. When the dye content is 0.001% by mass or more, the development time and peeling time can be further shortened, and when the content is 1.0% by mass or less, the resolution and adhesion can be further improved.

(Other ingredients)
The photosensitive resin composition can further contain other components as necessary. Other components include, for example, a photopolymerizable compound having at least one cationically polymerizable cyclic ether group in the molecule (such as an oxetane compound), a cationic polymerization initiator, tribromophenyl sulfone, a photocoloring agent, and a thermal coloration inhibitor. agent, plasticizer (p-toluenesulfonamide, etc.), silane coupling agent, pigment, filler, antifoaming agent, flame retardant, stabilizer, adhesion agent, leveling agent, release accelerator, antioxidant, fragrance , an imaging agent, a thermal crosslinking agent, and the like. These may be used alone or in combination of two or more. The content of other components may be about 0.01 to 20% by mass, respectively.

The photosensitive resin composition may contain at least one organic solvent in order to improve the handleability of the photosensitive composition and adjust the viscosity and storage stability. As the organic solvent, commonly used organic solvents can be used without particular limitation. Examples of the organic solvent include methanol, ethanol, acetone, methyl ethyl ketone, methyl cellosolve, ethyl cellosolve, toluene, N,N-dimethylformamide, propylene glycol monomethyl ether, and mixed solvents thereof. For example, components (A), (B), and (C) may be dissolved in an organic solvent and used as a solution with a solid content of approximately 30 to 60% by mass (hereinafter referred to as "coating solution"). I can do it. Note that the solid content refers to the remaining components after removing volatile components from the solution of the photosensitive resin composition.

(absorbance)
The photosensitive resin composition of this embodiment has an absorbance of 0.0030 to 0.0119 for light with a wavelength of 365 nm per 1 μm of thickness. When the absorbance is 0.0030 or more, a decrease in resolution can be suppressed. Furthermore, when the absorbance is 0.0119 or less, resolution and adhesion are improved. The above-mentioned absorbance may be 0.0040 or more, 0.0050 or more, or 0.0055 or more from the viewpoint of further suppressing a decrease in resolution, and 0.0100 or less from the viewpoint of further improving resolution and adhesion. It may be 0.0090 or less, or 0.0080 or less.

The absorbance of the photosensitive resin composition can be adjusted as appropriate by the types and contents of the above-mentioned (B) photopolymerizable compound, (C) photopolymerization initiator, sensitizer, and other components.

The absorbance of the photosensitive resin composition is determined by forming a film of the photosensitive resin composition to form a photosensitive layer, and measuring the absorbance of the photosensitive layer using, for example, a U-3310 spectrophotometer (manufactured by Hitachi High-Tech Science Co., Ltd.). The absorbance of light with a wavelength of 365 nm can be measured using an ultraviolet-visible spectrophotometer such as, for example, using a slide glass as a reference. The absorbance per 1 μm of thickness of the photosensitive resin composition can be determined by dividing the absorbance measured for the photosensitive layer by the thickness of the photosensitive layer (unit: μm).

[Photosensitive element]
The photosensitive element of this embodiment includes a support and a photosensitive layer containing the photosensitive resin composition formed on the support. When using the photosensitive element of this embodiment, the photosensitive layer may be laminated onto the substrate and then exposed to light without peeling off the support.

(Support)
As the support, a polymer film (support film) having heat resistance and solvent resistance, such as polyester such as polyethylene terephthalate (PET), polyolefin such as polypropylene and polyethylene, can be used. Among these, PET film may be used because it is easily available and has excellent handling properties in the manufacturing process (especially heat resistance, heat shrinkage rate, and breaking strength).

The haze of the support may be 0.01-1.0%, or 0.01-0.5%. When the haze of the support is 0.01% or more, it tends to be easier to manufacture the support itself, and when it is 1.0% or less, there is a tendency to reduce micro-defects that may occur in the resist pattern. Here, "haze" means cloudiness. Haze in the present disclosure refers to a value measured using a commercially available haze meter (turbidity meter) in accordance with the method specified in JIS K 7105. Haze can be measured, for example, with a commercially available turbidity meter such as NDH-5000 (manufactured by Nippon Denshoku Industries Co., Ltd.).

The number of particles with a diameter of 5 μm or more contained in the support may be 5 or less/mm ² , and the support may contain particles. This improves the slipperiness of the support surface, suppresses light scattering during exposure in a well-balanced manner, and improves resolution and adhesion. The average particle diameter of the particles may be 5 μm or less, 1 μm or less, or 0.1 μm or less. Note that the lower limit of the average particle diameter is not particularly limited, but may be 0.001 μm or more.

Commercially available such supports include, for example, "QS48" (Toray Industries, Inc.) and "FB40", which are biaxially oriented PET films with a three-layer structure containing particles in the outermost layer. (Toray Industries, Ltd.), "FS31" (Toray Industries, Ltd.), "R705G" (Mitsubishi Chemical Corporation), "HTF-01" (Teijin Film Solutions Ltd.), one layer containing particles was Examples include "A-1517" (Toyobo Co., Ltd.), a biaxially oriented PET film with a two-layer structure on the surface.

The thickness of the support may be 1-100 μm, 5-50 μm, or 5-30 μm. When the thickness is 1 μm or more, it is possible to suppress the support from being torn when it is peeled off, and when the thickness is 100 μm or less, it is possible to suppress the resolution from decreasing.

(middle class)
The photosensitive element may further include an intermediate layer between the support and the photosensitive layer. The intermediate layer may be a layer containing a water-soluble resin. Examples of water-soluble resins include resins containing polyvinyl alcohol as a main component.

(protective layer)
The photosensitive element may further include a protective layer if necessary. As the protective layer, a film may be used in which the adhesive force between the photosensitive layer and the protective layer is smaller than that between the photosensitive layer and the support, and a film with low fisheye may be used. May be used. Specifically, for example, those that can be used as the above-mentioned support may be mentioned. From the viewpoint of peelability from the photosensitive layer, a polyethylene film may be used. The thickness of the protective layer varies depending on the application, but may be about 1 to 100 μm.

[Method for manufacturing photosensitive element]
The photosensitive element can be manufactured, for example, as follows. The production of the photosensitive element includes preparing the coating solution described above, coating the coating solution on a support to form a coating layer, and drying the coating layer to form a photosensitive layer. It can be manufactured by the method. The coating liquid can be applied onto the support by known methods such as roll coating, comma coating, gravure coating, air knife coating, die coating, and bar coating.

Drying of the coating layer is not particularly limited as long as at least a portion of the organic solvent can be removed from the coating layer. Drying may be performed, for example, at 70 to 150° C. for about 5 to 30 minutes. After drying, the amount of organic solvent remaining in the photosensitive layer may be 2% by mass or less from the viewpoint of preventing diffusion of the organic solvent in subsequent steps.

The thickness of the photosensitive layer in the photosensitive element can be appropriately selected depending on the application, and may be 1 to 100 μm, 3 to 50 μm, 5 to 40 μm, or 10 to 30 μm after drying. When the thickness of the photosensitive layer is 1 μm or more, industrial coating becomes easy and productivity is improved, and when it is 100 μm or less, adhesiveness and resolution are further improved.

Since the photosensitive layer in the photosensitive element is a layer formed using the above photosensitive resin composition, the absorbance for light with a wavelength of 365 nm per 1 μm of thickness may be 0.0030 to 0.0119. When the absorbance is 0.0030 or more, a decrease in resolution can be suppressed. Furthermore, when the absorbance is 0.0119 or less, resolution and adhesion are improved. The above-mentioned absorbance may be 0.0040 or more, 0.0050 or more, or 0.0055 or more from the viewpoint of further suppressing a decrease in resolution, and 0.0100 or less from the viewpoint of further improving resolution and adhesion. It may be 0.0090 or less, or 0.0080 or less. The method for measuring the absorbance of the photosensitive layer is as described above.

The photosensitive element can be suitably used, for example, in the resist pattern forming method described below. Among these, from the viewpoint of resolution, it is suitable for application to manufacturing methods in which conductive patterns are formed by plating.

[Method for forming resist pattern]
The resist pattern forming method of the present embodiment includes a photosensitive layer forming step of laminating a photosensitive layer containing the photosensitive resin composition or a photosensitive layer of the photosensitive element on a substrate, and a predetermined portion of the photosensitive layer is exposed to actinic light. The method includes an exposure step of irradiating the photosensitive layer to form a photocured portion, and a development step of removing a region other than a predetermined portion of the photosensitive layer from the substrate. The resist pattern forming method may include other steps as necessary. Note that the resist pattern can be said to be a pattern of a photocured product of a photosensitive resin composition, or a relief pattern. Further, the method for forming a resist pattern can also be said to be a method for manufacturing a substrate with a resist pattern.

(Photosensitive layer forming process)
As a method for forming a photosensitive layer on a substrate, for example, a photosensitive resin composition may be applied and dried, or a protective layer may be removed from a photosensitive element and then the photosensitive layer of the photosensitive element may be heated. However, it may also be crimped onto the substrate. When a photosensitive element is used, a laminate consisting of a substrate, a photosensitive layer, and a support is obtained, which are laminated in this order. Although the substrate is not particularly limited, it is usually a circuit formation substrate comprising an insulating layer and a conductor layer formed on the insulating layer, a metal base material for metal mask manufacturing, or a die pad (for lead frame) made of an alloy base material, etc. base material) etc. are used.

The surface roughness (Ra) of the substrate may be 10 to 200 nm, 30 to 100 nm, or 40 to 100 nm from the viewpoint of further improving resolution. When Ra is 40 to 100 nm, halation due to irregularities on the substrate surface can be suppressed, and resolution can be further improved.

When using a photosensitive element, it is preferable to carry out under reduced pressure from the viewpoint of adhesion and followability. The photosensitive layer and/or the substrate may be heated at a temperature of 70 to 130° C. during pressure bonding. The pressure bonding may be performed at a pressure of approximately 0.1 to 1.0 MPa (approximately 1 to 10 kgf/cm ² ), but these conditions are appropriately selected as necessary. Note that if the photosensitive layer is heated to 70 to 130° C., it is not necessary to preheat the substrate, but it is also possible to preheat the substrate in order to further improve adhesion and followability.

(Exposure process)
In the exposure step, at least a portion of the photosensitive layer formed on the substrate is irradiated with actinic rays, so that the portion irradiated with the actinic rays is photocured and a latent image is formed. At this time, if the support present on the photosensitive layer is transparent to actinic rays, the actinic rays can be irradiated through the support, but if the support is light-shielding, the support After removing the photosensitive layer, the photosensitive layer is irradiated with actinic rays.

Examples of the exposure method include a method (mask exposure method) of irradiating actinic rays imagewise through a negative or positive mask pattern called artwork. Alternatively, a method of irradiating the image with actinic rays using a projection exposure method may be adopted.

As the active light source, known light sources can be used, such as carbon arc lamps, mercury vapor arc lamps, high pressure mercury lamps, ultra-high pressure mercury lamps, xenon lamps, gas lasers such as argon lasers, solid state lasers such as YAG lasers, A device that effectively emits ultraviolet rays and visible light, such as a semiconductor laser, is used. The wavelength of the actinic light may be in the range of 340 nm to 430 nm.

(Developing process)
In the development step, at least a portion of the photosensitive layer other than the photocured portion is removed from the substrate, thereby forming a resist pattern on the substrate. If a support is present on the photosensitive layer, the support is removed and then the area other than the photocured area (which can also be called an unexposed area) is removed (developed). Development methods include wet development and dry development, and wet development is widely used.

In the case of wet development, development is performed by a known development method using a developer compatible with the photosensitive resin composition. Development methods include methods using dip method, paddle method, spray method, brushing, slapping, scrubbing, rocking immersion, etc. From the viewpoint of improving resolution, high-pressure spray method may be used. . Development may be performed by combining two or more of these methods.

The composition of the developer is appropriately selected depending on the composition of the photosensitive resin composition. Examples include alkaline aqueous solutions and organic solvent developers.

An alkaline aqueous solution may be used as the developer because it is safe, stable, and has good operability. Bases for alkaline aqueous solutions include alkali hydroxides such as hydroxides of lithium, sodium or potassium; alkali carbonates such as carbonates or bicarbonates of lithium, sodium, potassium or ammonium; potassium phosphates, sodium phosphates, etc. Alkali metal phosphates; alkali metal pyrophosphates such as sodium pyrophosphate and potassium pyrophosphate; borax, sodium metasilicate, tetramethylammonium hydroxide, ethanolamine, ethylenediamine, diethylenetriamine, 2-amino-2-hydroxymethyl- 1,3-propanediol, 1,3-diaminopropanol-2, morpholine, etc. are used.

The alkaline aqueous solution used for development includes a dilute solution of 0.1 to 5% by mass of sodium carbonate, a dilute solution of 0.1 to 5% by mass of potassium carbonate, a dilute solution of 0.1 to 5% by mass of sodium hydroxide, and a dilute solution of 0.1 to 5% by mass of sodium hydroxide. A dilute solution of 1 to 5% by mass sodium tetraborate, etc. 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 can be adjusted depending on the alkaline developability of the photosensitive layer.

For example, a surfactant, an antifoaming agent, a small amount of an organic solvent for accelerating development, etc. may be mixed into the alkaline aqueous solution. Examples of organic solvents used in the alkaline aqueous solution include acetone, ethyl acetate, alkoxyethanol having an alkoxy group having 1 to 4 carbon atoms, ethyl alcohol, isopropyl alcohol, butyl alcohol, diethylene glycol monomethyl ether, 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. In order to prevent ignition, water may be added to these organic solvents in an amount in the range of 1 to 20% by mass to form an organic solvent developer.

In the method for forming a resist pattern in this embodiment, after removing the uncured portion in the development step, heating at about 60 to 250°C or exposure to about 0.2 to 10 J/cm ² is performed as necessary. The method may also include a step of further curing the resist pattern.

[Manufacturing method of printed wiring board]
The method for manufacturing a printed wiring board according to the present embodiment includes the step of etching or plating a substrate on which a resist pattern has been formed by the above-described method for forming a resist pattern to form a conductor pattern. The method for manufacturing a printed wiring board may include other steps such as a resist pattern removal step, if necessary.

In the plating process, the conductor layer provided on the substrate is plated using a resist pattern formed on the substrate as a mask. After the plating process, a conductor pattern may be formed by removing the resist by removing a resist pattern, which will be described later, and further etching the conductor layer covered with this resist.

The plating method may be electrolytic plating, electroless plating, or electroless plating. In the etching process, a conductor layer provided on the substrate is etched away using a resist pattern formed on the substrate as a mask to form a conductor pattern. The etching method is appropriately selected depending on the conductor layer to be removed. Examples of the etching solution include a cupric chloride solution, a ferric chloride solution, an alkaline etching solution, and a hydrogen peroxide-based etching solution.

After the etching process or plating process, the resist pattern on the substrate may be removed. The resist pattern can be removed, for example, using an aqueous solution that is more strongly alkaline than the alkaline aqueous solution used in the above-mentioned developing step. As this strong alkaline aqueous solution, for example, an amine stripping solution (15 volume % R-100S + 8 volume % R-101 aqueous solution (manufactured by Mitsubishi Gas Chemical Co., Ltd.)) is used. Further, as the strongly alkaline aqueous solution, a 1 to 10% by mass aqueous sodium hydroxide solution, a 1 to 10% by mass aqueous potassium hydroxide solution, etc. may be used.

When the resist pattern is removed after plating, the conductor layer covered with the resist is further etched by an etching process to form a conductor pattern, thereby manufacturing a desired printed wiring board. The etching method at this time is appropriately selected depending on 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 this embodiment is applicable not only to the manufacturing of single-layer printed wiring boards but also to the manufacturing of multilayer printed wiring boards, and also to the manufacturing of printed wiring boards having small-diameter through holes. It is possible.

[Examples 1 to 3 and Comparative Examples 1 to 2]
<Preparation of photosensitive resin composition>
Mixing (A) binder polymer with (B) photopolymerizable compound, (C) photopolymerization initiator, sensitizer, other components, and solvent in the amounts (parts by mass) shown in Table 2 below. Accordingly, photosensitive resin compositions of Examples and Comparative Examples were prepared. Note that the blending amounts of components other than the solvent shown in Table 2 are the mass of nonvolatile components (solid content). Table 2 also shows the evaluation results described below.

((A) Binder polymer)
A-1: Methylpropylene glycol/toluene solution of methacrylic acid/styrene/2-hydroxyethyl methacrylate/benzyl methacrylate copolymer (mass ratio: 27/50/3/20, weight average molecular weight: 35000)

((B) Photopolymerizable compound)
B-1: 2,2-bis(4-(methacryloxypentaethoxy)phenyl)propane (manufactured by Showa Denko Materials Co., Ltd., product name: FA-321M, number of EO groups: 10 (average value))
B-2: Ethoxylated bisphenol A dimethacrylate (number of EO groups: 2.6 (average value)) (manufactured by Kyoeisha Chemical Co., Ltd., product name: BP-2EM)
B-3: (PO) (EO) (PO) modified polyethylene glycol dimethacrylate (manufactured by Showa Denko Materials Co., Ltd., product name: FA-024M, number of EO groups: 6 (average value), number of PO groups :12 (average value))

((C) Photopolymerization initiator)
C-1: 2-(o-chlorophenyl)-4,5-diphenylbiimidazole (manufactured by Changzhou Strong Electronics New Materials Co., Ltd., compound represented by the following formula (IX))
C-2: 2-(o-chlorophenyl)-4,5-diphenylbiimidazole (manufactured by Changzhou Strong Electronics New Materials Co., Ltd., compound represented by the following formula (IX)), 2,2',5-tris- (o-chlorophenyl)-4-(3,4-dimethoxyphenyl)-4',5'-diphenylbiimidazole (manufactured by Changzhou Strong Electronics New Materials Co., Ltd., a compound represented by the following formula (X)), and Mixture of 2,4-bis-(o-chlorophenyl)-5-(3,4-dimethoxyphenyl)-diphenylbiimidazole (manufactured by Changzhou Strong Electronics New Materials Co., Ltd., compound represented by the following formula (XI)) C The compositions of -1 and C-2 are shown in Table 1. Table 1 shows the chemical formulas of each compound contained in C-1 and C-2, and the structures of Z ¹ and Z ² when represented by general formula (I). Further, the content shown in Table 1 indicates the content of each compound based on the total amount of C-1 or C-2.

(sensitizer)
D-1: 1-phenyl-3-(4-methoxystyryl)-5-(4-methoxyphenyl)pyrazoline (manufactured by Nihon Kagaku Kogyo Co., Ltd.)

(Other ingredients)
E-1: Leuco crystal violet (manufactured by Yamada Chemical Co., Ltd.) (hydrogen donor)
E-2: Malachite green (manufactured by Osaka Organic Chemical Industry Co., Ltd.) (dye)
E-3: tert-butylcatechol (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) (polymerization inhibitor)
E-4: Benzotriazole derivative (manufactured by Sanwa Kasei Co., Ltd., trade name: SF-808H (heterocyclic compound)
E-5: 2,2,6,6-tetramethyl-4-hydroxypiperidine-1-oxyl (manufactured by ADEKA Co., Ltd.) (polymerization inhibitor)

<Measurement of Mw of binder polymer>
The weight average molecular weight Mw of the binder polymer was determined by gel permeation chromatography (GPC) and calculated using a standard polystyrene calibration curve. The conditions for GPC are shown below.

(GPC conditions)
Column: Gelpack GL-R440, Gelpack GL-R450, and Gelpack GL-R400M (manufactured by Showa Denko Materials Co., Ltd.) Eluent: Tetrahydrofuran Measurement temperature: 40°C
Flow rate: 2.05mL/min Concentration: 5mg/mL
Injection volume: 200μL
Detector: Hitachi L-2490 RI (manufactured by Hitachi, Ltd.)

<Preparation of photosensitive element>
A solution of the photosensitive resin composition was uniformly applied onto a 16 μm thick polyethylene terephthalate film (manufactured by Toray Industries, Inc., trade name “FS-31”) serving as a support. Thereafter, it was dried for 10 minutes in a hot air convection dryer at 90° C. to form a photosensitive layer having a thickness of 25 μm after drying. Subsequently, a polyethylene film (manufactured by Tamapoly Co., Ltd., trade name "NF-15A") was laminated as a protective layer on the photosensitive layer to obtain a photosensitive element.

<Measurement of absorbance>
A photosensitive element was laminated on the surface of a slide glass (manufactured by Matsunami Glass Industry Co., Ltd., white slide glass cut-out No. 1 S1126). Lamination was performed using a heat roll at 110° C. with a pressure of 0.4 MPa and a roll speed of 1.0 m/min, while peeling off the protective layer so that the photosensitive layer of the photosensitive element was in contact with the surface of the slide glass. I went there. After laminating the photosensitive layer on the slide glass, the support was peeled off. The absorbance of the photosensitive layer was measured using a U-3310 spectrophotometer (manufactured by Hitachi High-Tech Science Co., Ltd.) under the following measurement conditions: wavelength range: 330 to 700 nm, scan speed: 300 nm/min, scan interval: 0.50 nm. It was measured. Baseline measurements were performed using untreated glass slides as references and samples. From the obtained measurement spectrum, the absorbance A at the exposure wavelength (365 nm) was recorded and used as the absorbance of the photosensitive layer. By dividing the absorbance of this photosensitive layer by the thickness of the photosensitive layer (25 μm), the absorbance per 1 μm of thickness was determined.

<Preparation of laminate>
A substrate prepared by sputtering copper onto a polyethylene terephthalate film was heated to 80° C., and a photosensitive element was laminated on the copper surface of the substrate. The laminate was laminated using a heat roll at 110°C with a pressure of 0.4 MPa and 1.0 m/min while peeling off the protective layer so that the photosensitive layer of the photosensitive element was in contact with the copper surface of the copper substrate. I did it at roll speed. Thereby, a laminate in which the substrate, photosensitive layer, and support were laminated in this order was obtained. The obtained laminate was used as a test piece for the test shown below.

<Measurement of minimum development time>
The support was peeled off from the test piece, the photosensitive layer was exposed, and a 1% by mass aqueous sodium carbonate solution at 30°C was sprayed. The time until the photosensitive layer was completely removed was measured and defined as the minimum development time.

<Evaluation of resolution and adhesion>
On the support of the test piece, a glass chrome type photo tool was placed as a negative for evaluating resolution and adhesion (resolution negative: line width/space width is 3x/x (x: 1 to 10, unit: μm) Adhesive negative: wire pattern with line width/space width x/3x (x: 1 to 18, unit: μm)), and an ultra-high pressure mercury lamp (365 nm). The photosensitive layer was exposed to light with a predetermined amount of energy using a projection exposure apparatus (manufactured by Ushio Inc., trade name "UX-2240-SM-XJ01") as a light source. After exposure, the support 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 unexposed areas (development treatment).

After development processing, the smallest line width/space width value among the resist patterns in which the space portions (unexposed portions) are cleanly removed and the line portions (exposed portions) are formed without twisting, meandering, or chipping. The resolution and adhesion were evaluated. At this time, the value of line width/space width evaluated as the above-mentioned predetermined energy amount is the exposure amount at which the resist line width of the adhesive negative pattern is 10 μm/10 μm, and the line width/space width is 10 μm/10 μm. It was recorded as the strength and adhesion. It means that the smaller this value is, the better the resolution and adhesion are.

<Evaluation of peeling time>
A glass chrome type photo tool (with a flat pattern of 50 mm x 40 mm) was used as a negative for peel test evaluation, and a projection exposure device (with an ultra-high pressure mercury lamp (365 nm) as a light source) was placed on the support of the test piece. The photosensitive layer was exposed to light using the above-mentioned predetermined energy amount using a photosensitive resin (manufactured by Ushio Inc., trade name "UX-2240-SM-XJ01"). After exposure, the support 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 portions.

After development, it was immersed in an amine stripping solution (15 volume % R-100S + 8 volume % R-101 aqueous solution, manufactured by Mitsubishi Gas Chemical Co., Ltd.) heated to 50°C. The time until the photosensitive layer was completely removed was measured and defined as the peeling time.

<Mandrel test>
A glass chrome type photo tool (with a strip pattern of 5 mm x 50 mm) was used as a negative for peel test evaluation on the support of the test piece, and a projection exposure device (with an ultra-high pressure mercury lamp (365 nm) as a light source) was used as a negative for peel test evaluation. The photosensitive layer was exposed to light using the above-mentioned predetermined energy amount using a photosensitive resin (manufactured by Ushio Inc., trade name "UX-2240-SM-XJ01"). After exposure, the support 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 portions.

After development, the presence or absence of cracks in the exposed photosensitive layer was confirmed in a bending resistance test conducted using a cylindrical mandrel with a diameter of 6 μm according to the cylindrical mandrel method (JIS K5600-5-1:1999). No cracks were evaluated as "A", and those with cracks were evaluated as "B".

Claims (17)

A photosensitive resin composition containing (A) a binder polymer, (B) a photopolymerizable compound, and (C) a photopolymerization initiator represented by the following general formula (I),
The photopolymerization initiator (C) is a first photopolymerization initiator represented by the following general formula (I) having no alkoxy group, and a first photopolymerization initiator represented by the following general formula (I) having an alkoxy group. and at least a photopolymerization initiator of 2.
The photosensitive resin composition has an absorbance of 0.0030 to 0.0119 for light with a wavelength of 365 nm per 1 μm of thickness.

[In formula (I), Z ¹ and Z ² each independently represent a monovalent group represented by the following general formula (II) or (III). ]


[In formula (II) and formula (III), R ¹ to R ³⁰ each independently represent a hydrogen atom, a halogen atom, or an alkoxy group having 1 to 5 carbon atoms, and a plurality of R ¹ to R ³⁰ in the same molecule When present, they may be the same or different. ] The photosensitive resin composition according to claim 1, wherein the second photoinitiator has at least one methoxy group. The photosensitive resin composition according to claim 1, wherein the content of the photopolymerization initiator (C) is 1 to 5% by mass based on the total solid content of the photosensitive resin composition. The photosensitive resin composition according to claim 1, wherein the binder polymer (A) includes a binder polymer having a divalent group represented by the following general formula (IV).

[In formula (IV), R ³¹ represents a hydrogen atom or a methyl group, R ³² represents a hydrogen atom, an alkyl group having 1 to 3 carbon atoms, an alkoxy group having 1 to 3 carbon atoms, a hydroxyl group, or a halogen atom, R ³² may be the same or different. ] The photosensitive resin composition according to claim 1, wherein the binder polymer (A) includes a binder polymer having a divalent group represented by the following general formula (V).

[In formula (V), R ³³ represents a hydrogen atom or a methyl group. ] The photosensitive resin composition according to claim 1, wherein the binder polymer (A) includes a binder polymer having a divalent group represented by the following general formula (VI).

[In formula (VI), R ³⁴ represents a hydrogen atom or a methyl group, R ³⁵ represents an alkyl group having 1 to 3 carbon atoms, an alkoxy group having 1 to 3 carbon atoms, a hydroxyl group or a halogen atom, and m is 0 to represents an integer of 5, and multiple R ^35s may be the same or different from each other. ] The photosensitive resin composition according to claim 1, wherein the binder polymer (A) includes a binder polymer having a divalent group represented by the following general formula (VII).

[In formula (VII), R ³⁶ represents a hydrogen atom or a methyl group, R ³⁷ represents an alkyl group having 1 to 3 carbon atoms, an alkoxy group having 1 to 3 carbon atoms, a hydroxyl group, or a halogen atom, and n is 0 to represents an integer of 5, and multiple R ^37s may be the same or different from each other. ] The photosensitive resin composition according to claim 1, wherein the binder polymer (A) includes a binder polymer having a weight average molecular weight of 20,000 to 50,000. The photosensitive resin composition according to claim 1, further comprising a heterocyclic compound. The photosensitive resin composition according to claim 1, further comprising a hydrogen-donating compound. The photosensitive resin composition according to claim 1, further comprising a polymerization inhibitor. The photosensitive resin composition according to claim 1, further comprising a dye. The photosensitive resin composition according to claim 1, wherein the content of the sensitizer is 0.065% by mass or less based on the total solid content of the photosensitive resin composition. A photosensitive element comprising a support and a photosensitive layer containing the photosensitive resin composition according to claim 1 formed on the support. A photosensitive layer forming step of laminating a photosensitive layer containing the photosensitive resin composition according to claim 1 or a photosensitive layer of the photosensitive element according to claim 14 on a substrate,
an exposure step of irradiating a predetermined portion of the photosensitive layer with actinic rays to form a photocured portion;
a developing step of removing a region other than the predetermined portion of the photosensitive layer from the substrate;
A method for forming a resist pattern. The method for forming a resist pattern according to claim 15, wherein the wavelength of the actinic light is within a range of 340 to 430 nm. A method for manufacturing a printed wiring board, comprising the 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 15 to form a conductor pattern.