Method for producing photosensitive element, photosensitive element, method for forming resist pattern, and method for producing printed wiring board

Abstract

This method for producing a photosensitive element comprises a step for using a photosensitive resin composition to form a photosensitive layer on a support film, wherein when a first surface is defined as a surface of the support film on the side opposite to the side on which the photosensitive layer is to be formed and a second surface is defined as a surface of the support film on the side on which the photosensitive layer is to be formed, the surface roughness Sq1 of the first surface is not more than 4.0 nm, and the total value Sq1 + Sq2 of the surface roughness Sq1 of the first surface and the surface roughness Sq2 of the second surface is not less than 9.0 nm.

Description

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

[0001] The present disclosure relates to a method for manufacturing a photosensitive element, a photosensitive element, a method for forming a resist pattern, and a method for manufacturing a printed wiring board.

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

[0003] A printed wiring board is manufactured using the photosensitive element, for example, by the following procedure. That is, first, the photosensitive layer of the photosensitive element is laminated onto a circuit-forming substrate such as a copper-clad laminate. At this time, the photosensitive layer is laminated so that the surface opposite to the surface in contact with the support film is in close contact with the surface of the circuit-forming substrate on which the circuit is to be formed. Furthermore, lamination is performed, for example, by heat-pressure bonding the photosensitive layer onto the circuit-forming substrate (atmospheric pressure lamination method).

[0004] Next, a desired region of the photosensitive layer is exposed to light through a support film using a mask film or the like, thereby generating radicals. The generated radicals pass through several reaction pathways and contribute to a crosslinking reaction (photocuring 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 in a developer to form a resist pattern. Next, using the resist pattern as a resist, an etching process or a plating process is performed to form a conductor pattern, and finally, the photocured portion of the photosensitive layer (resist pattern) is peeled off (removed).

[0005]

[0003] Meanwhile, with the recent trend toward higher density semiconductor package substrates and printed wiring boards, there is an increasing demand for photosensitive elements with excellent resolution and adhesion. In particular, in the manufacture of package substrates, there is a demand for photosensitive elements capable of forming resist patterns with a line width / space width of 10 / 10 (unit: μm) or less. For example, Patent Document 1 discusses the use of a specific photopolymerizable compound to improve resolution and adhesion.

[0006] JP 2013-195712 A

[0007] However, the present inventors have found that when a fine resist pattern having a line width / space width of 10 / 10 (unit: μm) or less is formed, if the smoothness of the sidewalls of the resist pattern is low, a problem occurs in that wiring shorts occur, resulting in a decrease in yield.

[0008] In order to solve the above problems, the present inventors focused on the support film through which light passes during exposure of the photosensitive layer, and investigated the influence of various support films on the smoothness of the sidewalls of the resist pattern. However, the present inventors found that, depending on the support film used, even if the smoothness of the sidewalls of the resist pattern can be improved, the support film may be prone to being scratched during the production of the photosensitive element, which may cause a new problem of defects in the resist pattern.

[0009] The present disclosure has been made in consideration of the problems associated with the above-described conventional techniques, and aims to provide a method for manufacturing a photosensitive element, a method for forming a photosensitive element and a resist pattern, and a method for manufacturing a printed wiring board, which can provide a photosensitive element with good smoothness on the sidewalls of a resist pattern and in which the occurrence of scratches on the support film is suppressed.

[0010] In order to achieve the above object, the present disclosure provides the following method for producing a photosensitive element, a photosensitive element, a method for forming a resist pattern, and a method for producing a printed wiring board.

[0011] [1] A process for forming a photosensitive layer on a support film using a photosensitive resin composition is provided, and when the surface of the support film opposite to the side on which the photosensitive layer is formed is defined as a first surface and the surface on which the photosensitive layer is formed is defined as a second surface, the surface roughness Sq of the first surface is １ is 4.0 nm or less, and the surface roughness Sq of the first surface １ and the surface roughness Sq of the second surface ２ The sum of Sq １ +Sq ２ [2] A method for producing a photosensitive element, wherein Sq １ +Sq ２ [3] The method for producing a photosensitive element according to the above [1], wherein Sq ２ -Sq １ [4] A photosensitive element according to the above [1] or [2], wherein the surface of the support film opposite to the photosensitive layer is designated as a first surface, and the surface of the support film facing the photosensitive layer is designated as a second surface, and the surface roughness Sq of the first surface is 1.0 nm or more. １ is 4.0 nm or less, and the surface roughness Sq of the first surface １ and the surface roughness Sq of the second surface ２ The sum of Sq １ +Sq ２ [5] Sq １ +Sq ２ [6] The photosensitive element according to the above [4], wherein Sq ２ -Sq １ [7] The photosensitive element according to the above [4] or [5], wherein the thickness of the film is 1.0 nm or more over the entire area of ​​the support film and 2 m ２The photosensitive element according to any one of [4] to [6] above, wherein, when the smaller of the areas of the first and second surfaces of the support film is observed, no recesses or cracks with a maximum length of 50 μm or more are observed on either the first surface or the second surface of the support film. [8] A method for forming a resist pattern using the photosensitive element according to any one of [4] to [7] above, comprising the steps of: placing a photosensitive layer and a support film on a substrate in this order from the substrate side; exposing the photosensitive layer to actinic light through the support film; and removing the support film and then removing the uncured portion of the photosensitive layer from the substrate. [9] A method for producing a printed wiring board, comprising the step of etching or plating a substrate on which a resist pattern has been formed by the method for forming a resist pattern according to [8] above, to form a conductor pattern.

[0012] According to the present disclosure, it is possible to provide a method for manufacturing a photosensitive element, a method for forming a photosensitive element and a resist pattern, and a method for manufacturing a printed wiring board, which can provide a photosensitive element with good smoothness on the sidewalls of a resist pattern and in which the occurrence of scratches on the support film is suppressed.

[0013] 1 is a schematic cross-sectional view showing one embodiment of a photosensitive element according to the present disclosure. 2 is a diagram showing an example of a process for producing a printed wiring board by a semi-additive method.

[0014] Preferred embodiments of the present disclosure will be described in detail below, with reference to the drawings as necessary. It goes without saying that, in the following embodiments, the components (including element steps, etc.) are not necessarily essential unless otherwise specified or considered to be clearly essential in principle. The same applies to numerical values ​​and ranges, and they should not be construed as unduly limiting the present disclosure.

[0015] In this specification, (meth)acrylic acid means at least one of acrylic acid and the corresponding methacrylic acid. 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. When multiple substances corresponding to each component are present in the composition, the content of each component in the composition means the total amount of the multiple substances present in the composition, unless otherwise specified.

[0016] In addition, in this specification, the term "solid content" refers to non-volatile content excluding volatile substances such as water, organic solvents, etc. In other words, it refers to components other than solvents such as water and organic solvents that remain without volatilizing during the drying process, and includes liquid, starch syrup-like, and wax-like substances at room temperature around 25°C.

[0017] Furthermore, in this specification, the term "process" includes not only an independent process but also a process that cannot be clearly distinguished from other processes as long as the intended effect of the process is achieved.

[0018] Furthermore, in this specification, a numerical range indicated using "to" indicates a range that includes the numerical values ​​before and after "to" as the minimum and maximum values, respectively. In addition, in a numerical range described in stages in this specification, the upper limit or lower limit of a numerical range of a certain stage may be replaced with the upper limit or lower limit of a numerical range of another stage. In addition, in a numerical range described in this specification, the upper limit or lower limit of the numerical range may be replaced with a value shown in the examples. In addition, in this specification, the term "layer" encompasses a structure that is formed over the entire surface when observed in a plan view, as well as a structure that is formed in a part of the surface.

[0019] [Photosensitive element and manufacturing method thereof] The manufacturing method of the photosensitive element of the present embodiment includes a step of forming a photosensitive layer on a support film using a photosensitive resin composition, and when the surface of the support film opposite to the side on which the photosensitive layer is formed is defined as a first surface and the surface on which the photosensitive layer is formed is defined as a second surface, the surface roughness Sq of the first surface is １ is 4.0 nm or less, and the surface roughness Sq of the first surface １ and the surface roughness of the second surface Sq２ The sum of Sq １ +Sq ２ The photosensitive element 1 of this embodiment produced by the above-described production method includes a support film 2 and a photosensitive layer 3 in this order, and may further include other layers such as a protective layer 4, as shown in FIG. 1 . When the surface of the support film 2 opposite to the photosensitive layer 3 is defined as a first surface F1 and the surface on the photosensitive layer 3 side is defined as a second surface F2, the surface roughness Sq of the first surface F1 is 9.0 nm or more. １ is 4.0 nm or less, and the surface roughness Sq of the first surface F1 is １ and the surface roughness Sq of the second surface F2 ２ The sum of Sq １ +Sq ２ Each layer in the photosensitive element and the method for producing the same according to this embodiment will be described in detail below.

[0020] <Support Film> Examples of the support film of this embodiment 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. Among these, polyester films may be used. By using a polyester film as the support film, the mechanical strength and heat resistance of the support film tend to be improved. Furthermore, from the viewpoint of improving the slipperiness and winding property, a polyester film containing particles (lubricant, etc.) may be used. When a polyester film containing particles (lubricant, etc.) is used, a photosensitive layer may be formed on the surface having the particles (lubricant, etc.). As such a polyester film, for example, a polyester film into which particles (lubricant, etc.) are kneaded, a polyester film having a layer containing particles (lubricant, etc.) formed on both sides, or a polyester film having a layer containing particles (lubricant, etc.) formed on one side may be used. Among these, Sq １ and Sq ２It is preferable to use a polyester film having particles (such as a lubricant) only on the side on which the photosensitive layer is formed (the second surface F2 side), because this easily satisfies the above-mentioned conditions. The support film may be single-layered or multi-layered.

[0021] Methods for adding particles such as a lubricant to a support film include, for example, kneading particles (lubricant, etc.) into the support film, and forming a layer containing particles (lubricant, etc.) on the support film using a known method such as roll coating, flow coating, spray coating, curtain flow coating, dip coating, slit die coating, etc. When the support film contains particles such as a lubricant, the particle size may be, for example, 0.1 to 2.0 μm.

[0022] The support film has a surface roughness Sq of the first surface F1. １ is 4.0 nm or less, and the surface roughness Sq of the first surface F1 is １ and the surface roughness Sq of the second surface F2 ２ The sum of Sq １ +Sq ２ is 9.0 nm or more. １ When the photosensitive layer is exposed to light through the support film, the surface roughness Sq of the first surface F1 is 4.0 nm or less. １ This can suppress the refraction of the exposed light due to the influence of Sq, and improve the smoothness of the sidewalls of the resist pattern. １ +Sq ２ When the thickness is 9.0 nm or more, it is possible to prevent scratches on the support film caused by rubbing of the support films against each other during the production of the photosensitive element.

[0023] Surface roughness Sq means the root mean square height. Surface roughness Sq of the support film １ and Sq ２ can be measured, for example, by a scanning white light interference microscope.

[0024] The above Sq １ However, from the viewpoint of improving the smoothness of the sidewalls of the resist pattern, it may be 3.8 nm or less, or 3.7 nm or less. On the other hand, from the viewpoint of further suppressing the occurrence of scratches on the support film during the production of the photosensitive element, Sq１ may be 2.5 nm or more, or 3.0 nm or more.

[0025] The above Sq ２ is not particularly limited, but may be 8.0 nm or less, or 7.5 nm or less, from the viewpoint of improving the smoothness of the sidewalls of the resist pattern. ２ may be 1.0 nm or more, or 1.5 nm or more.

[0026] The above Sq １ +Sq ２ is 9.0 nm or more, but from the viewpoint of further suppressing the occurrence of scratches on the support film, it may be 9.1 nm or more, or 9.2 nm or more. On the other hand, from the viewpoint of further improving the smoothness of the sidewalls of the resist pattern, Sq １ +Sq ２ may be 12.0 nm or less, or 11.5 nm or less.

[0027] The above Sq １ and the above Sq ２ The difference between Sq ２ -Sq １ is not particularly limited, but from the viewpoint of achieving a good balance between smoothness of the resist pattern sidewalls and suppression of scratches on the support film, it may be 1.0 nm or more, or 1.1 nm or more, and may be 3.0 nm or less, or 2.5 nm or less.

[0028] The haze of the support film may be 0.01 to 5.0%, 0.01 to 1.5%, 0.01 to 1.0%, or 0.01 to 0.5%. The haze of the support film may be less than 0.5%. A haze of 0.01% or more tends to facilitate the production of the support film itself, while a haze of 5.0% or less tends to facilitate the detection of foreign matter in the photosensitive layer when forming the photosensitive layer of the photosensitive element. Here, "haze" refers to the degree of cloudiness. The 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 K7105. Haze can be measured, for example, using a commercially available turbidity meter such as NDH-5000 (product name, manufactured by Nippon Denshoku Industries Co., Ltd.).

[0029] 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. Having a support film thickness of 1 μm or more tends to prevent the support film from being torn when peeled off. Furthermore, having a support film thickness of 200 μm or less tends to improve the lamination properties of the resist and to be more economically beneficial.

[0030] The support film is irradiated with light from the support film side of the photosensitive element to measure the total area of ​​the support film and 2 m ２ When observing the smaller area of ​​the above areas, it is preferable that no recesses or cracks with a maximum length of 50 μm or more are observed on either the first or second surface of the support film. This condition can be met by producing a photosensitive element by the production method of this embodiment. Furthermore, by using a photosensitive element equipped with a support film that satisfies the above condition, a resist pattern without defects can be formed.

[0031] <Photosensitive Layer> The photosensitive layer of this embodiment is a layer formed using a photosensitive resin composition described below. The photosensitive resin composition can be used for a desired purpose as long as its properties change when irradiated with light (for example, it is photocured), and may be either negative or positive. The photosensitive resin composition may contain (A) a binder polymer, (B) a photopolymerizable compound, and (C) a photopolymerization initiator. Furthermore, it may contain (D) a photosensitizer, a polymerization inhibitor, or other components, as necessary. Each component used in the photosensitive resin composition of this embodiment will be described in more detail below.

[0032] ((A) Binder Polymer) The (A) binder polymer (hereinafter also referred to as "component (A)") can be produced, for example, by radical polymerization of a polymerizable monomer. Examples of the polymerizable monomer include polymerizable styrene derivatives substituted at the α-position or at the aromatic ring, such as styrene, vinyltoluene, and α-methylstyrene; acrylamides such as diacetone acrylamide; acrylonitrile; ethers of vinyl alcohol such as vinyl-n-butyl ether; (meth)acrylic acid alkyl esters; (meth)acrylic acid benzyl esters such as benzyl methacrylate; (meth)acrylic acid tetrahydrofurfuryl esters; (meth)acrylic acid dimethylaminoethyl esters; and (meth)acrylic acid diethylaminoethyl esters. Examples of suitable acrylic acid include esters, (meth)acrylic acid glycidyl esters, 2,2,2-trifluoroethyl (meth)acrylate, 2,2,3,3-tetrafluoropropyl (meth)acrylate, (meth)acrylic acid, α-bromoacrylic acid, α-chloroacrylic acid, β-furyl (meth)acrylic acid, β-styryl (meth)acrylic acid, maleic acid, maleic anhydride, maleic acid monoesters such as monomethyl maleate, monoethyl maleate, and monoisopropyl maleate, fumaric acid, cinnamic acid, α-cyanocinnamic acid, itaconic acid, crotonic acid, and propiolic acid. These may be used alone or in combination of two or more.

[0033] Among these, from the viewpoint of improving plasticity, a (meth)acrylic acid alkyl ester may be contained. Examples of the (meth)acrylic acid alkyl ester include a compound represented by the following general formula (I) and compounds in which the alkyl group of these compounds is substituted with a hydroxyl group, an epoxy group, a halogen group, or the like. ２ C=C(R ６ )-COOR ７ (I)

[0034] In general formula (I), R ６ represents a hydrogen atom or a methyl group, and R ７ represents an alkyl group having 1 to 12 carbon atoms. ７Examples of the alkyl group having 1 to 12 carbon atoms represented by the formula (I) 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, an undecyl group, a dodecyl group, and structural isomers of these groups.

[0035] Examples of (meth)acrylic acid alkyl esters represented by the general formula (I) include (meth)acrylic acid methyl ester, (meth)acrylic acid ethyl ester, (meth)acrylic acid propyl ester, (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 acid nonyl ester, (meth)acrylic acid decyl ester, (meth)acrylic acid undecyl ester, (meth)acrylic acid dodecyl ester, etc. These may be used alone or in combination of two or more.

[0036] Furthermore, from the viewpoint of alkaline developability, the component (A) may contain a carboxy group. The component (A) containing a carboxy group can be produced, for example, by radical polymerization of a polymerizable monomer having a carboxy group with another polymerizable monomer. The polymerizable monomer having a carboxy group may be (meth)acrylic acid or methacrylic acid. The acid value of the component (A) containing a carboxy group may be 50 to 250 mgKOH / g, 50 to 200 mgKOH / g, or 100 to 200 mgKOH / g.

[0037] From the viewpoint of improving the balance between alkaline developability and alkaline resistance in a good balance, the carboxy group content of component (A) (the incorporation ratio of polymerizable monomers having a carboxy group relative to the total amount of polymerizable monomers used in the binder polymer) may be 12 to 50 mass%, 12 to 40 mass%, 15 to 35 mass%, 15 to 30 mass%, or 20 to 30 mass%. When this carboxy group content is 12 mass% or more, alkaline developability tends to be improved, and when it is 50 mass% or less, alkaline resistance tends to be excellent.

[0038] The content of the structural unit derived from the polymerizable monomer having a carboxy group in component (A) correlates with the blending ratio of the polymerizable monomer having a carboxy group, and may be 12 to 50 mass%, 12 to 40 mass%, 15 to 35 mass%, 15 to 30 mass%, or 20 to 30 mass%.

[0039] Furthermore, from the viewpoint of adhesion and chemical resistance, component (A) may use styrene or a styrene derivative as the polymerizable monomer. When styrene or a styrene derivative is used as the polymerizable monomer, its content (the blending ratio of styrene or a styrene derivative relative to the total amount of polymerizable monomers used in component (A)) 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, from the viewpoint of further improving adhesion and chemical resistance. When this content is 10% by mass or more, adhesion tends to be improved, while when it is 60% by mass or less, it is possible to prevent peeled pieces from becoming large during development, and the time required for peeling tends to be kept from increasing.

[0040] The content of structural units derived from styrene or a styrene derivative in component (A) correlates with the blending ratio of the styrene or styrene derivative, and may be 10 to 60 mass%, 15 to 50 mass%, 30 to 50 mass%, 35 to 50 mass%, or 40 to 50 mass%.

[0041] From the viewpoints of resolution and aspect ratio, component (A) may also use a benzyl (meth)acrylate ester as the polymerizable monomer. From the viewpoint of further improving resolution and aspect ratio, the content of structural units derived from benzyl (meth)acrylate ester in component (A) may be 15 to 50 mass%, 15 to 45 mass%, 15 to 40 mass%, 15 to 35 mass%, or 20 to 30 mass%.

[0042] These binder polymers can be used alone or in combination of two or more. When two or more types are used in combination, examples of the component (A) include two or more binder polymers made of different polymerizable monomers, two or more binder polymers having different weight average molecular weights, and two or more binder polymers having different dispersities.

[0043] Component (A) can be produced by a conventional method, for example, by radical polymerization of an alkyl (meth)acrylate, (meth)acrylic acid, and styrene or the like.

[0044] From the viewpoint of improving mechanical strength and alkaline developability in a well-balanced manner, the weight average molecular weight of component (A) may be 20,000 to 300,000, 40,000 to 150,000, 40,000 to 120,000, or 50,000 to 80,000. When the weight average molecular weight of component (A) is 20,000 or more, developer resistance tends to be excellent, while when it is 300,000 or less, prolonged development time tends to be suppressed. Note that the weight average molecular weight in this specification is a value measured by gel permeation chromatography (GPC) and converted using a calibration curve prepared using standard polystyrene.

[0045] The content of the component (A) may be 30 to 80 parts by mass, 40 to 75 parts by mass, 50 to 70 parts by mass, or 50 to 60 parts by mass, relative to 100 parts by mass of the total solid content of the component (A) and the component (B), which will be described later. When the content of the component (A) is within this range, the film-forming properties of the photosensitive resin composition and the strength of the photocured part are improved.

[0046] (Photopolymerizable Compound (B)) The photosensitive resin composition according to this embodiment may contain a photopolymerizable compound (B) (hereinafter also referred to as "component (B)"). The component (B) can be any photopolymerizable or photocrosslinkable compound without any particular limitation, and for example, a compound having at least one ethylenically unsaturated bond in the molecule can be used.

[0047] The component (B) may contain a bisphenol-type (meth)acrylate compound. Examples of bisphenol-type (meth)acrylate compounds include 2,2-bis(4-((meth)acryloxypolyethoxy)phenyl)propane, 2,2-bis(4-((meth)acryloxypolypropoxy)phenyl)propane, and 2,2-bis(4-((meth)acryloxypolyethoxypolypropoxy)phenyl)propane. These may be used alone or in combination of two or more. Furthermore, the bisphenol-type (meth)acrylate compound may contain 2,2-bis(4-(methacryloxypentaethoxy)phenyl)propane and 2,2-bis(4-(methacryloxydiethoxy)phenyl)propane.

[0048] Commercially available bisphenol (meth)acrylate compounds include, for example, 2,2-bis(4-(methacryloxydiethoxy)phenyl)propane ("BPE-200" manufactured by Shin-Nakamura Chemical Co., Ltd.), 2,2-bis(4-(methacryloxypentaethoxy)phenyl)propane ("BPE-500" manufactured by Shin-Nakamura Chemical Co., Ltd. or "FA-321M" manufactured by Resonac Corporation), 2,2-bis(4-(methacryloxypentadecaethoxy)phenyl)propane ("BPE-1300" manufactured by Shin-Nakamura Chemical Co., Ltd.), and 2,2-bis(4-(methacryloxypolyethoxy)phenyl)propane ("BP-2EM" manufactured by Kyoeisha Chemical Co., Ltd. (EO group: 2.6 (average value)).

[0049] From the viewpoint of further improving chemical resistance, the content of the bisphenol type (meth)acrylate compound may be 1 to 50 mass%, 3 to 40 mass%, 10 to 40 mass%, 20 to 40 mass%, or 30 to 40 mass%, relative to the total solid content of the (A) component and the (B) component.

[0050] Furthermore, from the viewpoint of further improving chemical resistance, the content of the bisphenol type (meth)acrylate compound may be 30 to 99 mass%, 50 to 97 mass%, 60 to 95 mass%, 70 to 95 mass%, or 80 to 90 mass%, relative to the total solid content of the component (B).

[0051] The content of component (B) may be 20 to 70 parts by mass, 25 to 60 parts by mass, or 30 to 50 parts by mass, based on 100 parts by mass of the total solid content of components (A) and (B). When the content of component (B) is within this range, the photosensitive resin composition exhibits improved resolution, adhesion, and suppression of resist tail formation, as well as improved photosensitivity and film-forming properties.

[0052] (Photopolymerization Initiator (C)) The photosensitive resin composition according to this embodiment may contain at least one photopolymerization initiator (C) (hereinafter also referred to as "component (C)"). The component (C) is not particularly limited as long as it can polymerize component (B), and can be appropriately selected from commonly used photopolymerization initiators.

[0053] Examples of component (C) include aromatic ketones such as 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)-butanone-1 and 2-methyl-1-[4-(methylthio)phenyl]-2-morpholino-propanone-1, quinones such as alkylanthraquinones, benzoin ether compounds such as benzoin alkyl ethers, benzoin compounds such as benzoin and alkylbenzoins, benzyl derivatives such as benzyl dimethyl ketal, 2,4,5-triarylimidazole dimers such as 2-(o-chlorophenyl)-4,5-diphenylimidazole dimer and 2-(o-fluorophenyl)-4,5-diphenylimidazole dimer, and acridine derivatives such as 9-phenylacridine and 1,7-(9,9'-acridinyl)heptane. These can be used alone or in combination of two or more.

[0054] Among these, from the viewpoint of improving resolution, 2,4,5-triarylimidazole dimer may be contained. Examples of the 2,4,5-triarylimidazole dimer include 2-(o-chlorophenyl)-4,5-diphenylimidazole dimer, 2-(o-chlorophenyl)-4,5-bis-(m-methoxyphenyl)imidazole dimer, and 2-(p-methoxyphenyl)-4,5-diphenylimidazole dimer. Among these, from the viewpoint of improving photosensitivity stability, 2-(o-chlorophenyl)-4,5-diphenylimidazole dimer may be contained.

[0055] As the 2,4,5-triarylimidazole dimer, for example, 2,2'-bis(2-chlorophenyl)-4,4',5,5'-tetraphenylbiimidazole is commercially available as B-CIM (product name, manufactured by Hodogaya Chemical Co., Ltd.).

[0056] From the viewpoints of further improving photosensitivity and adhesion and further suppressing the light absorption of component (C), component (C) may contain at least one kind of 2,4,5-triarylimidazole dimer, or may contain 2-(2-chlorophenyl)-4,5-diphenylimidazole dimer. The 2,4,5-triarylimidazole dimer may have a symmetric or asymmetric structure.

[0057] The amount of component (C) may be 0.01 to 30 parts by mass, 0.1 to 10 parts by mass, 1 to 7 parts by mass, 1 to 6 parts by mass, 1 to 5 parts by mass, or 2 to 5 parts by mass, relative to 100 parts by mass of the total solids content of components (A) and (B). When the amount of component (C) is 0.01 part by mass or more, photosensitivity, resolution, and adhesion tend to be improved, while when it is 30 parts by mass or less, the resist pattern shape tends to be excellent.

[0058] (Photosensitizer (D)) The photosensitive resin composition according to this embodiment may contain a photosensitizer (D) (hereinafter also referred to as "component (D)"). By containing the component (D), it tends to be possible to effectively utilize the absorption wavelength of actinic rays used for exposure.

[0059] Examples of component (D) include pyrazolines, dialkylaminobenzophenones, anthracenes, coumarins, acridines, xanthones, oxazoles, benzoxazoles, thiazoles, benzothiazoles, triazoles, stilbenes, triazines, thiophenes, naphthalimides, and triarylamines. These can be used alone or in combination of two or more. From the viewpoint of more effectively utilizing the absorption wavelength of the actinic radiation used for exposure, component (D) may include pyrazolines, anthracenes, coumarins, acridines, or dialkylaminobenzophenones, and particularly may include coumarins, acridines, or dialkylaminobenzophenones, or may include dialkylaminobenzophenones. Commercially available dialkylaminobenzophenones include, for example, "EAB" manufactured by Hodogaya Chemical Co., Ltd.

[0060] When component (D) is contained, its content may be 1.0 part by mass or less, 0.5 part by mass or less, 0.15 part by mass or less, 0.12 part by mass or less, or 0.10 part by mass or less, based on 100 parts by mass of the total solid content of components (A) and (B). When the content of component (D) is 1.0 part by mass or less, based on 100 parts by mass of the total solid content of components (A) and (B), deterioration of the resist pattern shape and the tendency to produce resist tails can be suppressed, and resolution tends to be improved. Furthermore, from the viewpoint of easily obtaining high photosensitivity and good resolution, the content of component (D) may be 0.01 part by mass or more, based on 100 parts by mass of the total solid content of components (A) and (B).

[0061] (Polymerization Inhibitor) The photosensitive resin composition according to this embodiment may contain a polymerization inhibitor. By containing a polymerization inhibitor, it tends to be possible to adjust the exposure dose required for photocuring the photosensitive resin composition to an optimal exposure dose for exposure using a projection exposure machine. Examples of the polymerization inhibitor include alkyl catechols such as catechol, resorcinol (resorcin), 1,4-hydroquinone, 2-methylcatechol, 3-methylcatechol, 4-methylcatechol, 2-ethylcatechol, 3-ethylcatechol, 4-ethylcatechol, 2-propylcatechol, 3-propylcatechol, 4-propylcatechol, 2-n-butylcatechol, 3-n-butylcatechol, 4-n-butylcatechol, 2-tert-butylcatechol, 3-tert-butylcatechol, 4-tert-butylcatechol, and 3,5-di-tert-butylcatechol; Examples of the resorcinol include alkyl resorcinols such as orcinol, 4-methylresorcinol, 5-methylresorcinol (orcinol), 2-ethylresorcinol, 4-ethylresorcinol, 2-propylresorcinol, 4-propylresorcinol, 2-n-butylresorcinol, 4-n-butylresorcinol, 2-tert-butylresorcinol, and 4-tert-butylresorcinol, alkylhydroquinones such as methylhydroquinone, ethylhydroquinone, propylhydroquinone, tert-butylhydroquinone, and 2,5-di-tert-butylhydroquinone, pyrogallol, and phloroglucinol. These may be used alone or in combination of two or more.

[0062] (Other Components) The photosensitive resin composition according to this embodiment may contain, as needed, 0.01 to 20 parts by mass of each of the following additives, relative to 100 parts by mass of the total solids content of component (A) and component (B): dyes such as malachite green, Victoria Pure Blue, brilliant green, and methyl violet; photocoloring agents such as tribromophenyl sulfone, leuco crystal violet, diphenylamine, benzylamine, triphenylamine, diethylaniline, and o-chloroaniline; thermal color-forming inhibitors; plasticizers such as p-toluenesulfonamide; pigments; fillers; defoamers; flame retardants; adhesion promoters; leveling agents; release promoters; antioxidants; fragrances; imaging agents; and thermal crosslinking agents. These additives may be used alone or in combination of two or more.

[0063] Furthermore, the photosensitive resin composition according to this embodiment may contain at least one organic solvent as needed to improve the handleability of the photosensitive composition or to adjust the viscosity and storage stability. As the organic solvent, any commonly used organic solvent can be used without particular limitation. Specific examples include organic solvents such as methanol, ethanol, acetone, methyl ethyl ketone, methyl cellosolve, ethyl cellosolve, toluene, N,N-dimethylformamide, and propylene glycol monomethyl ether, as well as mixed solvents thereof. These may be used alone or in combination of two or more.

[0064] <Protective Layer> In the photosensitive element of this embodiment, a protective layer may be laminated on the surface of the photosensitive layer opposite to the surface in contact with the support film. For example, a polymer film such as polyethylene or polypropylene may be used as the protective layer. Furthermore, the same polymer film as the support film described above may be used, or a different polymer film may be used.

[0065] A method for producing a photosensitive element in which a support film, a photosensitive layer, and a protective layer are laminated in this order will be described below.

[0066] <Method for producing photosensitive element> The photosensitive element can be produced by applying a photosensitive resin composition to the second surface F2 of the support film, drying the composition to form a photosensitive layer, and then laminating a protective layer on the photosensitive layer.

[0067] The photosensitive resin composition can be applied to the support film by a known method such as roll coating, comma coating, gravure coating, air knife coating, die coating, bar coating, or spray coating.

[0068] The method for drying the applied photosensitive resin composition is not particularly limited as long as it can remove at least a portion of the solvent such as water, but it may be dried for 5 to 30 minutes at 70 to 150° C. After drying, the amount of solvent remaining in the photosensitive layer may be 2% by mass or less from the viewpoint of preventing the diffusion of the solvent in subsequent steps.

[0069] The thickness of the photosensitive layer in the photosensitive element can be appropriately selected depending on the application, and may be 1 μm or more, 5 μm or more, or 10 μm or more after drying, or 200 μm or less, 100 μm or less, 50 μm or less, or less than 20 μm. When the thickness of the photosensitive layer is 1 μm or more, 5 μm or more, or 10 μm or more, industrial coating tends to be easier and productivity tends to be improved. Furthermore, when the thickness of the photosensitive layer is 200 μm or less, 100 μm or less, 50 μm or less, or less than 20 μm, the photosensitivity is high and the photocuring property of the resist bottom is excellent, so that a resist pattern with excellent resolution and aspect ratio tends to be formed.

[0070] The melt viscosity of the photosensitive layer in the photosensitive element at 110°C can be appropriately selected depending on the type of substrate (undercoat) that comes into contact with the photosensitive layer, but may be 50 to 10,000 Pa s, 100 to 5,000 Pa s, or 200 to 1,000 Pa s at 110°C after drying. When the melt viscosity at 110°C is 50 Pa s or more, wrinkles and voids do not occur during the lamination step, and productivity tends to improve. Furthermore, when the melt viscosity at 110°C is 10,000 Pa s or less, adhesion to the undercoat improves during the lamination step, and adhesion defects tend to be reduced.

[0071] 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 wound into a roll around a core. When wound into a roll, it may be wound so that the support film is on the outside. Examples of materials for the core include plastics such as polyethylene resin, polypropylene resin, polystyrene resin, polyvinyl chloride resin, and ABS resin (acrylonitrile-butadiene-styrene copolymer).

[0072] The end faces of the photosensitive element roll thus obtained may be provided with end separators from the viewpoint of end face protection, or may be provided with moisture-proof end face separators from the viewpoint of edge fusion resistance. The photosensitive element roll may be packaged in a black sheet with low moisture permeability.

[0073] The photosensitive element according to this embodiment can be suitably used, for example, in the method for forming a resist pattern and the method for producing a printed wiring board, which will be described later.

[0074] [Method of Forming Resist Pattern] The method of forming a resist pattern according to this embodiment includes the following steps: (i) using the photosensitive element to arrange a photosensitive layer and a support film on a substrate in this order from the substrate side (hereinafter also referred to as "(i) photosensitive layer forming step"); (ii) exposing the photosensitive layer to actinic rays through the support film (hereinafter also referred to as "(ii) exposure step"); and (iii) removing the support film and removing the uncured portion of the photosensitive layer from the substrate (hereinafter also referred to as "(iii) development step"). Other steps may also be included as necessary. The resist pattern can also be referred to as a photocured product pattern of a photosensitive resin composition or a relief pattern. Depending on the purpose, the resist pattern in this embodiment may be used as a resist or for other purposes such as a protective film.

[0075] (i) Photosensitive Layer Forming Step In the photosensitive layer forming step, a photosensitive layer is formed on a substrate using the photosensitive element. The substrate is not particularly limited, but typically, a circuit-forming substrate having an insulating layer and a conductor layer formed on the insulating layer, or a die pad (substrate for lead frame) such as an alloy substrate is used.

[0076] As a method for forming a photosensitive layer on a substrate, for example, when a photosensitive element having a protective layer is used, the protective layer is removed, and then the photosensitive layer of the photosensitive element is pressed onto the substrate while being heated, thereby forming the photosensitive layer on the substrate, thereby obtaining a laminate having the substrate, the photosensitive layer, and the support film in this order.

[0077] When the photosensitive layer forming step is carried out using a photosensitive element, the step may be carried out under reduced pressure from the viewpoint of adhesion and followability. Heating during pressure bonding may be carried out at a temperature of 70 to 130°C, and pressure bonding may be carried out at 0.1 to 1.0 MPa (1 to 10 kgf / cm ２ These conditions can be appropriately selected as needed. Note that if the photosensitive layer of the photosensitive element is heated to 70 to 130°C, it is not necessary to preheat the substrate, but the substrate can be preheated in order to further improve the adhesion and followability.

[0078] (ii) Exposure Step) In the exposure step, the photosensitive layer is exposed to actinic rays via the support film. As a result, the exposed areas irradiated with actinic rays may be photocured to form photocured areas (latent images), or the unexposed areas not irradiated with actinic rays may be photocured to form photocured areas. When the photosensitive layer is exposed with the support film peeled off, the presence of oxygen tends to inhibit curing of the photosensitive layer, making it difficult to form a normal resist pattern. However, by exposing the photosensitive layer via the support film, the above-mentioned oxygen inhibition is suppressed, and a normal resist pattern can be formed.

[0079] As the exposure method, known exposure methods can be applied, such as a method of irradiating an actinic ray in an imagewise manner through a negative or positive mask pattern called artwork (mask exposure method), an LDI (Laser Direct Imaging) exposure method, or a method of irradiating an actinic ray projected from a photomask image through a lens in an imagewise manner (projection exposure method). Among these, the projection exposure method may be used from the viewpoint of excellent resolution. In other words, the photosensitive element according to this embodiment may be applied to the projection exposure method. The projection exposure method can also be said to be an exposure method using actinic ray with attenuated energy.

[0080] The light source for actinic rays is not particularly limited as long as it is a commonly used, well-known light source. For example, those that effectively emit ultraviolet light, such as carbon arc lamps, mercury vapor arc lamps, ultra-high pressure mercury lamps, high-pressure mercury lamps, xenon lamps, gas lasers such as argon lasers, solid-state lasers such as YAG lasers, and semiconductor lasers such as gallium nitride blue-violet lasers, can be used. Also, those that effectively emit visible light, such as photographic flood lamps and sun lamps, can be used. Among these, from the viewpoint of improving resolution and alignment in a well-balanced manner, light sources capable of emitting monochromatic i-line light with an exposure wavelength of 365 nm, light sources capable of emitting monochromatic h-line light with an exposure wavelength of 405 nm, or light sources capable of emitting actinic rays with exposure wavelengths that are cross-linked with i, h, and g may be used. In particular, light sources capable of emitting monochromatic i-line light with an exposure wavelength of 365 nm may be used. Examples of light sources capable of emitting monochromatic i-line light with an exposure wavelength of 365 nm include ultra-high pressure mercury lamps.

[0081] ((iii) Development Step) In the development step, the support film is peeled off and removed from the photosensitive layer, and then the uncured portions of the photosensitive layer are removed from the substrate. By the development step, a resist pattern consisting of photocured portions of the photosensitive layer is formed on the substrate. Examples of the development method include wet development.

[0082] In the case of wet development, development can be carried out by a known wet development method using a developer suitable for the photosensitive resin composition. Examples of wet development methods include dipping, puddling, high-pressure spraying, brushing, slapping, scrubbing, and swinging immersion, and from the viewpoint of improving resolution, the high-pressure spraying method is most suitable. These wet development methods may be used alone or in combination of two or more methods.

[0083] The developer is appropriately selected depending on the composition of the photosensitive resin composition, and examples thereof include alkaline aqueous solutions and organic solvent developers.

[0084] From the viewpoints of safety, stability, and ease of use, an alkaline aqueous solution may be used as the developer. Examples of the base for the alkaline aqueous solution include alkali hydroxides such as lithium, sodium, or potassium hydroxide, alkali carbonates such as carbonates or bicarbonates of lithium, sodium, potassium, or ammonium, alkali metal phosphates such as potassium phosphate and sodium phosphate, alkali metal pyrophosphates such as sodium pyrophosphate and potassium pyrophosphate, sodium borate, sodium metasilicate, tetramethylammonium hydroxide, ethanolamine, ethylenediamine, diethylenetriamine, 2-amino-2-hydroxymethyl-1,3-propanediol, 1,3-diamino-2-propanol, and morpholine.

[0085] Examples of alkaline aqueous solutions used for development include a dilute solution of 0.1 to 5% by weight sodium carbonate, a dilute solution of 0.1 to 5% by weight potassium carbonate, a dilute solution of 0.1 to 5% by weight sodium hydroxide, and a dilute solution of 0.1 to 5% by weight sodium tetraborate. 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. The alkaline aqueous solution may also contain, for example, a surfactant, an antifoaming agent, or a small amount of an organic solvent to promote development. Examples of organic solvents used in alkaline aqueous solutions include 3-acetone alcohol, acetone, ethyl acetate, an 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.

[0086] Examples of organic solvents 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 used as the organic solvent developer by adding water in a range of 1 to 20% by mass.

[0087] (Other Steps) In the method for forming a resist pattern according to this embodiment, after removing the uncured portion in the development step, heating at 60 to 250° C. or irradiating with 0.2 to 10 J / cm 2 is performed as necessary. ２ The method may further include a step of hardening the resist pattern by exposing the resist pattern to light at an exposure dose of 1000 ppm or more.

[0088] [Method for manufacturing a printed wiring board] The method for manufacturing a printed wiring board according to this embodiment includes a step of forming a conductor pattern by etching or plating a substrate on which a resist pattern has been formed by the above-described method for forming a resist pattern, and may also include other steps such as a resist pattern removal step as necessary. The method for manufacturing a printed wiring board according to this embodiment can be suitably used to form a conductor pattern by using the above-described method for forming a resist pattern using a photosensitive element, but is particularly suitable for application to a method for forming a conductor pattern by plating. The conductor pattern can also be considered a circuit.

[0089] In the etching process, a resist pattern formed on a substrate having a conductive layer is used as a mask to etch away the conductive layer of the substrate that is not covered with the resist, thereby forming a conductive pattern.

[0090] 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. A ferric chloride solution may also be used because of its good etch factor.

[0091] On the other hand, in plating, a resist pattern formed on a substrate having a conductor layer is used as a mask to plate copper, solder, etc. on the conductor layer of the substrate that is not covered with the resist. After plating, the resist is removed by removing the resist pattern as described below, and the conductor layer that was covered with the resist is then etched to form a conductor pattern.

[0092] The plating method may be either electrolytic plating or electroless plating, but electroless plating is particularly preferred. Examples of electroless plating include copper plating such as copper sulfate plating and copper pyrophosphate plating, solder plating such as high-throw solder plating, nickel plating such as Watts bath (nickel sulfate-nickel chloride) plating and nickel sulfamate plating, and gold plating such as hard gold plating and soft gold plating.

[0093] After the etching or plating process, the resist pattern on the substrate is removed. The resist pattern can be removed, for example, with an aqueous solution that is more strongly alkaline than the aqueous alkaline solution used in the development step. Examples of such strongly alkaline aqueous solutions include a 1 to 10% by mass aqueous solution of sodium hydroxide and a 1 to 10% by mass aqueous solution of potassium hydroxide. Of these, a 1 to 5% by mass aqueous solution of sodium hydroxide or potassium hydroxide may be used.

[0094] Methods for removing the resist pattern include, for example, a dipping method and a spray method, which may be used alone or in combination.

[0095] When the resist pattern is removed after plating, the conductor layer covered with the resist is further etched by etching to form a conductor pattern, thereby manufacturing a desired printed wiring board. The etching method used here is appropriately selected depending on the conductor layer to be removed. For example, the above-mentioned etching solution can be used.

[0096] The method for manufacturing a printed wiring board according to this embodiment can be applied to the manufacture of not only single-layer printed wiring boards but also multi-layer printed wiring boards, and can also be applied to the manufacture of printed wiring boards having small-diameter through holes.

[0097] The method for manufacturing a printed wiring board according to this embodiment can be suitably used for manufacturing high-density packaging substrates, particularly for manufacturing wiring boards using a semi-additive process. An example of a manufacturing process for a wiring board using a semi-additive process is shown in FIG.

[0098] In FIG. 2( a), a substrate (circuit-forming substrate) is prepared in which a conductor layer 40 is formed on an insulating layer 50. The conductor layer 40 is, for example, a copper layer. In FIG. 2( b), a photosensitive layer 30 and a support film 20 are formed on the conductor layer 40 of the substrate by the photosensitive layer formation process. In FIG. 2( c), the exposure process involves irradiating the photosensitive layer 30 with active light 80, which projects a photomask image onto the photosensitive layer 30 through the support film 20, to form a photocured portion in the photosensitive layer 30. In FIG. 2( d), a development process involves removing areas of the substrate other than the photocured portion formed by the exposure process, thereby forming a resist pattern 32, which is a photocured portion, on the substrate. In FIG. 2( e), a plating process is performed using the resist pattern 32, which is a photocured portion, as a mask to form a plating layer 60 on the conductor layer 40 of the substrate that is not covered by resist. 2( f), the photocured resist pattern 32 is peeled off with a strong alkaline aqueous solution, and then the conductor layer 40 masked by the resist pattern 32 is removed by flash etching, forming a plating layer 62 after etching and a conductor pattern 70 including the conductor layer 42 after etching. The conductor layer 40 and the plating layer 60 may be made of the same material or different materials. 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. Note that although the projection exposure method is described in FIG. 2, the resist pattern 32 may also be formed using a combination of a mask exposure method and an LDI exposure method.

[0099] Although the preferred embodiments of the present disclosure have been described above, the present disclosure is not limited to the above embodiments.

[0100] Hereinafter, the present disclosure will be described more specifically based on examples, but the present disclosure is not limited to the following examples.

[0101] [Examples 1 and 2 and Comparative Examples 1 to 5] <Preparation of Photosensitive Resin Compositions> Next, photosensitive resin compositions were obtained by mixing the components shown in Table 1 below in the amounts (unit: parts by mass) shown in the same table. The blending amounts of components other than the solvent shown in Table 1 are the mass of non-volatile content (solid content).

[0102]

[0103] Details of each component in Table 1 are as follows: (A) Binder polymer) A-1: ​​Methylpropylene glycol / toluene solution of a copolymer of methacrylic acid / styrene / 2-hydroxyethyl methacrylate / benzyl methacrylate (mass ratio: 27 / 50 / 3 / 20, weight average molecular weight: 35,000)

[0104] ((B) Photopolymerizable Compound) B-1: 2,2-bis(4-(methacryloxypentaethoxy)phenyl)propane (manufactured by Resonac Co., Ltd., trade name: FA-321M, number of EO groups: 10 (average)) B-2: Ethoxylated bisphenol A dimethacrylate (number of EO groups: 2.6 (average)) (manufactured by Kyoeisha Chemical Co., Ltd., trade name: BP-2EM) B-3: (PO)(EO)(PO)-modified polyethylene glycol dimethacrylate (manufactured by Resonac Co., Ltd., trade name: FA-024M, number of EO groups: 6 (average), number of PO groups: 12 (average))

[0105] ((C) Photopolymerization initiator) C-1: 2-(o-chlorophenyl)-4,5-diphenylbiimidazole (manufactured by Changzhou Strong Electronic New Materials Co., Ltd.) ((D) Photosensitizer) D-1: 1-phenyl-3-(4-methoxystyryl)-5-(4-methoxyphenyl)pyrazoline (manufactured by Nippon Chemical Industry Co., Ltd.)

[0106] (Other Components) E-1: Leuco Crystal Violet (manufactured by Yamada Chemical Co., Ltd.) (hydrogen donor) E-2: Malachite Green (manufactured by Osaka Organic Chemical Industry Ltd.) (dye) E-3: tert-butylcatechol (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) (polymerization inhibitor) E-4: Benzotriazole derivative (manufactured by Sanwa Chemical Industry Co., Ltd., trade name: SF-808H (heterocyclic compound)) E-5: 2,2,6,6-tetramethyl-4-hydroxypiperidine-1-oxyl (manufactured by ADEKA Corporation) (polymerization inhibitor)

[0107] <Preparation of Photosensitive Element> (Preparation of Support Film) A support film having a surface roughness Sq shown in Table 2 was prepared for the photosensitive element. １ (surface roughness of the first surface) and Sq ２PET films having a surface roughness of 16 μm (surface roughness on the second surface side) were prepared. The thickness of each PET film was 16 μm. Table 2 also shows whether the PET films of the examples and comparative examples contained a lubricant and whether the lubricant was present on the first or second surface. The surface roughness Sq of the PET film １ and Sq ２ was measured by the method described below.

[0108] A solution of the photosensitive resin composition was uniformly applied to the second surface of the PET film (support film). The coating was then dried for 10 minutes in a hot air convection dryer at 90°C to form a photosensitive layer having a dry thickness of 25 μm. A polyethylene film (manufactured by Tamapoly Co., Ltd., product name "NF-15A") was then laminated on the photosensitive layer as a protective layer to obtain a photosensitive element.

[0109] <Surface roughness Sq of the support film １ and Sq ２ Measurement of Surface Roughness> The support film (PET film) was peeled off from the photosensitive element, and the surface shapes of the first and second surfaces of the support film were measured using a scanning white light interference microscope VS1540 (Hitachi High-Tech Science Corporation, magnification: 50x, measurement device: piezo, measurement mode: Plase, scan speed: 4 μm, field of view size: 128 μm × 128 μm, scan range: 3 to −3 μm, number of effective pixels: 50). Interpolation and fourth-order surface correction were performed on the obtained image, and the calculated Sq value was used as the surface roughness value of the support film. Note that for support films that were determined to be “scratched” in the scratch evaluation described below, surface roughness measurements were performed on portions that were free of scratches (recesses or cracks with a maximum length of 50 μm or more). It was also confirmed that the surface roughness values ​​measured by the above method did not change from the surface roughness values ​​of the support film in its initial state before the photosensitive element was manufactured.

[0110] <Evaluation of scratches on support film> 2m ２The photosensitive element was irradiated with light from an LED lamp from the support film side, and the first and second surfaces of the support film were visually inspected for the presence or absence of depressions or cracks with a maximum length of 50 μm or more. When one or more depressions or cracks with a maximum length of 50 μm or more were observed on the first or second surface of the support film, it was judged as "scratches present," and when none were observed, it was judged as "no scratches." The results are shown in Table 2.

[0111] <Evaluation of Smoothness of Resist Pattern Sidewalls> (Preparation of Laminate) A Cu-sputtered PET film (manufactured by Geomatec Co., Ltd., thickness: 125 μm, Ra<50 nm) was heated to 80°C as a substrate, and while peeling off the protective layer, the photosensitive elements were each pressure-bonded to the substrate so that the photosensitive layer was in contact with the copper surface. Pressure-bonding was performed using a heat roll at 110°C under a pressure of 0.40 MPa at a roll speed of 1.0 m / min. In this way, a laminate was obtained in which the substrate, photosensitive layer, and support film were laminated in this order. These laminates were used as test pieces in the tests described below. As the laminator, an HLM-3000 (product name, manufactured by Taisei Laminator Co., Ltd.) was used. Here, for photosensitive elements that were determined to be "scratched" in the evaluation of scratches on the support film, a portion of the support film that was free of scratches (recesses or cracks with a maximum length of 50 μm or more) was cut out, and the laminate was prepared using the photosensitive element.

[0112] (Measurement of Minimum Development Time) The support film was peeled off from the test piece to expose the photosensitive layer, and a 1% by mass aqueous solution of sodium carbonate at 30° C. was sprayed on the exposed photosensitive layer. The time until the photosensitive layer was completely removed was measured and defined as the minimum development time.

[0113] (Formation of Resist Pattern) A glass chrome type phototool (size: 9 cm × 9 cm, having a wiring pattern with a line width / space width of 5 μm / 5 μm) was placed as a negative on the support film of the test piece, and a projection exposure apparatus (manufactured by Ushio Inc., product name "UX-2240-SM-XJ01") using an ultra-high pressure mercury lamp (365 nm) as a light source was used to expose the resist pattern at 110 mJ / cm ２After the exposure, the support film was peeled off, and a 1% by mass aqueous solution of sodium carbonate at 30°C was sprayed onto the exposed photosensitive layer for a time twice the minimum developing time, thereby removing the unexposed portions and forming a resist pattern.

[0114] (LER Measurement) The LER (Line Edge Roughness) of the resist pattern formed by the above method was measured by the following method. That is, using a Computer Numerical Control image measurement system (manufactured by Nikon Corporation, product name "NEXIV VMZ-R4540"), an image of an area where a resist pattern with a line width / space width of 5 μm / 5 μm was formed was taken. The contour of the resist pattern on the substrate was identified by scanning measurement using the NEXIV VMZ-R4540, and the coordinates of the contour of the resist pattern were measured for six lines of the resist pattern. In the coordinate measurement, coordinates of 260 points, spaced 52 μm apart at 0.2 μm intervals, were measured for each of the contours on one side and the other side of the line. In addition, these measurements were performed at three locations for each of the six lines. As a result, the coordinates of a total of 9,360 points were measured. Then, based on the coordinates of the 9,360 measured points, the variation (3σ) of the resist pattern outline was calculated. σ is the standard deviation, and 3σ of the resist pattern outline is the LER (Line Edge Roughness). The smaller the LER, the higher the smoothness of the resist pattern sidewall. The results are shown in Table 2.

[0115] <Evaluation of Resist Pattern Defects> For photosensitive elements judged to be "scratched" in the evaluation of scratches on the support film, a resist pattern was formed in the same manner as in the evaluation of the smoothness of the resist pattern sidewalls, except that a photosensitive element cut out from a portion of the support film with scratches (recesses or cracks with a maximum length of 50 μm or more) was used. The formed resist pattern was visually observed for the presence or absence of defects. Here, "defects" refers to chips in the resist pattern that can be visually confirmed. The results are shown in Table 2.

[0116]

[0117] DESCRIPTION OF SYMBOLS 1... photosensitive element, 2, 20... support film, 3, 30... photosensitive layer, 4... protective layer, 32... resist pattern, 40... conductor layer, 42... conductor layer after etching treatment, 50... insulating layer, 60... plating layer, 62... plating layer after etching treatment, 70... conductor pattern, 80... actinic light.

Claims

1. A method for manufacturing a photosensitive film, comprising the steps of: forming a photosensitive layer on a support film using a photosensitive resin composition; and, when the surface of the support film opposite to the side on which the photosensitive layer is formed is designated as a first surface, and the surface on which the photosensitive layer is formed is designated as a second surface, the surface roughness Sq of the first surface is: １ is 4.0 nm or less, and the surface roughness Sq １ and the surface roughness Sq of the second surface ２ The sum of Sq １ +Sq ２ is 9.0 nm or greater.

2. Sq １ +Sq ２ The method of claim 1 , wherein the thickness of the photosensitive element is less than or equal to 12.0 nm.

3. Sq ２ -Sq １ The method of claim 1 , wherein the thickness of the photosensitive element is 1.0 nm or greater.

4. A photosensitive element having a support film and a photosensitive layer, wherein the surface of the support film opposite to the photosensitive layer is a first surface, and the surface on the photosensitive layer side is a second surface, the surface roughness Sq of the first surface being: １ is 4.0 nm or less, and the surface roughness Sq １ and the surface roughness Sq of the second surface ２ The sum of Sq １ +Sq ２ is 9.0 nm or greater.

5. Sq １ +Sq ２ The photosensitive element of claim 4 , wherein the n is 12.0 nm or less.

6. Sq ２ -Sq １ The photosensitive element of claim 4 , wherein the n is 1.0 nm or greater.

7. Irradiate the photosensitive element from the support film side with light to measure the entire area of ​​the support film and 2 m ２ 5. The photosensitive element of claim 4, wherein when the smaller of the areas of said first surface and said second surface of said support film is observed, no depressions or cracks having a maximum length of 50 μm or more are observed on either said first surface or said second surface of said support film.

8. A method for forming a resist pattern, comprising the steps of: using the photosensitive element according to any one of claims 4 to 7, arranging a photosensitive layer and a support film on a substrate in this order from the substrate side; exposing the photosensitive layer to active light through the support film; and removing the support film and then removing the uncured portion of the photosensitive layer from the substrate.

9. A method for producing a printed wiring board, comprising the step of etching or plating a substrate on which a resist pattern has been formed by the method for forming a resist pattern according to claim 8 to form a conductor pattern.

Images