JP2007114731A - Photosensitive element - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a photosensitive element capable of forming a resist pattern with sufficiently excellent resolution and photosensitivity, and capable of suppressing adhesion of foreign substances to a support film and sticking of a photomask. <P>SOLUTION: The photosensitive element 1 comprises a support film 10 and a layer 20 comprising a photosensitive resin composition disposed on the first principal surface 12 of the support film 10, wherein the support film 10 has a haze of ≤1.0% and the second principal surface 14 of the support film 10 has a surface resistivity of ≤10<SP>13</SP>Ω. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a photosensitive element.

  Conventionally, in the field of production of printed wiring boards, as a resist material used for etching, plating, etc., a photosensitive material composed of a layer made of a photosensitive resin composition (hereinafter referred to as “photosensitive layer”), a support film and a protective film. Sex elements are widely used. A printed wiring board is manufactured as follows, for example. First, after peeling off the protective film of the photosensitive element from the photosensitive layer, the photosensitive layer is laminated on the conductive film of the circuit forming substrate. Next, after pattern exposure is performed on the photosensitive layer, an unexposed portion is removed with a developing solution to form a resist pattern. And a printed wiring board is formed by patterning a conductive film based on this resist pattern.

  As a developer used for removing the unexposed portion, an alkali developing type such as a sodium hydrogen carbonate solution is mainly used. The developer generally needs to have an ability to dissolve the photosensitive layer to some extent, and at the time of development, the photosensitive layer is dissolved or dispersed in the developer. In recent years, the contact area between a circuit-forming substrate and a photosensitive layer that is a resist material has been reduced with the increase in the density of printed wiring boards. For this reason, the photosensitive layer is required to have excellent mechanical strength, chemical resistance, and flexibility in the etching or plating process, as well as excellent adhesion to the circuit forming substrate and excellent resolution in pattern formation. Yes.

  Usually, when forming a resist using a photosensitive element, the photosensitive layer is laminated on a substrate and then exposed without peeling off the support film. In order to cope with such an exposure process, a light-transmitting material may be employed for the support film. On the other hand, in order to obtain high resolution in pattern formation, it is necessary to make the support film as thin as possible. However, in order to apply the photosensitive resin composition with a uniform thickness on the support film, the support film is required to have a certain thickness (generally 15 μm to 25 μm). Therefore, conventional support films tend not to meet the demand for higher resolution in consideration of the applicability of the photosensitive resin composition.

  As a method for achieving high resolution, there is a method in which a support film provided on a photosensitive element is peeled off before exposure and exposed without using a support film. In this case, the phototool may be directly adhered to the photosensitive layer. However, since the photosensitive layer usually has a certain degree of adhesiveness, it is difficult to remove the adhered phototool when the phototool is directly adhered to the photosensitive layer for exposure. Further, the phototool is contaminated by the photosensitive layer, or the photosensitive layer is exposed to oxygen in the atmosphere by peeling the support film, so that the photosensitivity is likely to be lowered.

In order to improve the above points, various means have been proposed. For example, Patent Documents 1 and 2 propose a method of providing an intermediate layer between a support film and a photosensitive layer. Patent Documents 3 and 4 disclose a method in which two or more photosensitive layers are formed, and a layer that directly adheres to the phototool is made non-adhesive.
JP 59-097138 A JP-A 63-197942 JP-A-01-221735 Japanese Patent Laid-Open No. 02-230149

  However, the means described in Patent Documents 1 to 4 require an extra coating process for providing an intermediate layer or a plurality of photosensitive layers, which increases the number of manufacturing processes. Further, in the means described in Patent Documents 1 and 2, since the intermediate layer is thin, handling of the photosensitive element is not easy. Furthermore, in the methods described in Patent Documents 3 and 4, since the photosensitive layer is exposed to oxygen in the atmosphere, it is difficult to maintain its photosensitivity high.

  As a means for obtaining an excellent resolution and photosensitivity for the photosensitive element while at the same time avoiding an increase in its production process, a method of suppressing light scattering that occurs during exposure by reducing the haze of the support film can be considered. However, if the haze of the support film is simply reduced, foreign matters such as dust and dust existing in the surrounding environment will adhere. In addition, as a result of studies by the present inventors, it has been found that if the haze of the support film is simply reduced, a photomask is attached to the support film, which tends to hinder the production of a printed wiring board. .

  The present invention has been made in view of the above circumstances, and can form a resist pattern with sufficiently excellent resolution and photosensitivity, and at the same time sufficiently adheres foreign matter to a support film and attaches a photomask. An object of the present invention is to provide a photosensitive element that can be reduced to a low level.

The present invention is a photosensitive element comprising a support film and a layer made of a photosensitive resin composition provided on the first main surface of the support film, wherein the haze of the support film is 1. Provided is a photosensitive element having a surface resistivity of 10 ¹³ Ω or less that is 0% or less and that has a second main surface opposite to the first main surface of the support film.

  The present inventors have found that the adhesion of foreign matters to a conventional photosensitive element and the attachment to a support film such as a photomask are caused by an increase in surface resistivity accompanying a decrease in haze of the support film. It was. Therefore, it is considered that the above-described object can be achieved if not only haze but also a film having a sufficiently low surface resistivity is adopted as the support film, and the present invention described above has been completed.

  The support film in the photosensitive element of the present invention may be a film containing as a main component one or more polymers selected from the group consisting of polyethylene terephthalate, polypropylene, polyethylene and polyester.

  The photosensitive resin composition constituting the photosensitive layer in the present invention preferably contains a binder polymer, a photopolymerizable compound having an ethylenically unsaturated bond polymerizable in the molecule, and a photopolymerization initiator. .

  According to the present invention, it is possible to form a resist pattern with sufficiently excellent resolution and photosensitivity, and at the same time, it is possible to sufficiently reduce adhesion of foreign matter to the support film and adhesion of a photomask and / or a photosensitive layer. It becomes possible to provide a photosensitive element.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings as necessary. In the drawings, the same elements are denoted by the same reference numerals, and redundant description is omitted. Further, the dimensional ratios in the drawings are not limited to the illustrated ratios. In the present specification, “(meth) acrylic acid” means “acrylic acid” and “methacrylic acid” corresponding thereto, “(meth) acrylate”, “acrylate” and “methacrylate” corresponding thereto, “(Meth) acryloxy group” means “acryloxy group” and its corresponding “methacryloxy group”, and “(meth) acryloyl group” means “acryloyl group” and its corresponding “methacryloyl group”.

  FIG. 1 is a schematic cross-sectional view showing a preferred embodiment of the photosensitive element of the present invention. The photosensitive element 1 shown in FIG. 1 includes a support film 10 and a photosensitive layer 20. The photosensitive layer 20 is provided on the first main surface 12 of the support film 10. The support film 10 has a second main surface 14 on the side opposite to the first main surface 12.

The support film 10 has a haze of 1.0% or less and a surface resistivity of the second main surface 14 of 10 ¹³ Ω or less. Here, “haze” means haze, and is a value measured using a commercially available haze meter (turbidimeter) in accordance with the method defined in JIS K 7105.

  The haze of the support film 10 is preferably 0 to 1.0%, more preferably 0 to 0.5%, and still more preferably 0 to 0.3%. If the haze exceeds 1.0%, the resolution tends to decrease and the side surface of the resist pattern tends to deteriorate.

The surface resistivity (hereinafter simply referred to as “surface resistivity”) of the second main surface 14 of the support film 10 is preferably 10 ¹² Ω or less, and more preferably 10 ¹¹ Ω or less. When the surface resistivity exceeds 10 ¹³ Ω, when a resist pattern is formed using the photosensitive element 1, static electricity is likely to be generated when the photosensitive layer 20 is laminated and exposed. Thereby, adhesion of foreign matter to the support film 10 and sticking of the photomask and / or the photosensitive layer 20 to the support film 10 tend to occur easily. The surface resistivity can be measured using a 4329A type high resistance meter manufactured by Hewlett-Packard Company. The measurement temperature at this time is 26 ° C., and the measurement time is 1 minute.

  The haze of the support film 10 can be adjusted within the above numerical range by a conventionally known method. Further, the surface resistivity of the support film 10 can be adjusted within the above numerical range by adding an appropriate amount of an antistatic agent to the film raw material when producing the film.

Moreover, the surface resistivity of the support body film 10 can also be adjusted as follows. That is, the support film 10 has a multilayer structure of two or more layers, and among those layers, a layer having a second principal surface with a surface resistivity of 10 ¹³ Ω or less is adopted. And the support body film 10 is obtained by laminating | stacking the layer which has a 2nd main surface, and another layer. At this time, the thickness of the layer having the second main surface is reduced so that the haze of the support film 10 is 1.0% or less.

  As is clear from the above, the support film 10 may be a single layer or multiple layers. However, in order to easily adjust both the haze and the surface resistivity within the above numerical range, a multilayer structure of two or more layers is preferable. In addition, the support film 10 may contain an antistatic agent or the like, if necessary, as long as the photosensitive characteristics are not impaired.

  The material of the support film 10 is not particularly limited as long as the haze and the surface resistivity satisfy the above conditions. Examples of the material of the support film 10 include one or more films selected from the group consisting of polyethylene terephthalate, polypropylene, polyethylene, and polyester.

  Moreover, the support body film 10 which can be used as a support body film of the photosensitive element 1 out of a commercially available general industrial film may be appropriately processed and used. Examples of commercially available general industrial films that can be used as the support film 10 include “Cosmo Shine A-1517” (trade name, manufactured by Toyobo Co., Ltd.), which is a polyester film.

  The thickness of the support film 10 is preferably 5 to 20 μm, more preferably 8 to 18 μm, and still more preferably 10 to 16 μm. When the thickness is less than 5 μm, the support film 10 tends to be easily broken when the support film 10 is peeled from the photosensitive element 1. On the other hand, when the thickness exceeds 20 μm, the resolution tends to be lowered and the cost is liable to be inferior.

  The photosensitive layer 20 is a layer made of a photosensitive resin composition. The photosensitive resin composition constituting the photosensitive layer 20 includes (A) a binder polymer, (B) a photopolymerizable compound having an ethylenically unsaturated bond polymerizable in the molecule, and (C) a photopolymerization initiator. It is preferable to contain. Hereafter, each said component is demonstrated in detail.

  The binder polymer as component (A) is not particularly limited as long as it is used in conventional photosensitive resin compositions. For example, acrylic resin, styrene resin, epoxy resin, amide resin Amide epoxy resin, alkyd resin, phenol resin and the like. Of these, acrylic resins are preferred from the standpoint of alkali developability. These are used singly or in combination of two or more.

  The binder polymer can be produced by radical polymerization of a polymerizable monomer. Polymerizable monomers include polymerizable styrene derivatives such as styrene, vinyl toluene, α-methyl styrene, p-methyl styrene, and p-ethyl styrene, and esters of vinyl alcohol such as acrylamide, acrylonitrile, and vinyl n-butyl ether. , (Meth) acrylic acid alkyl ester, (meth) acrylic acid tetrahydrofurfuryl ester, (meth) acrylic acid dimethylaminoethyl ester, (meth) acrylic acid diethylaminoethyl ester, (meth) acrylic acid glycidyl ester, 2,2 , 2-trifluoroethyl (meth) acrylate, 2,2,3,3-tetrafluoropropyl (meth) acrylate, (meth) acrylic acid, α-bromo (meth) acrylic acid, α-chloro (meth) acrylic acid , Β-furyl (meth) acrylic , Β-styryl (meth) acrylic acid, maleic acid, maleic anhydride, monomethyl maleate, monoethyl maleate, monoisopropyl maleate, monoesters of fumaric acid, cinnamic acid, α-cyanocinnamic acid, Itaconic acid, crotonic acid and propiolic acid are mentioned.

  As said (meth) acrylic-acid alkylester, what the alkyl group of an ester site | part is a C1-C12 alkyl group is mentioned. Examples of the (meth) acrylic acid alkyl ester include, for example, methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, butyl (meth) acrylate, pentyl (meth) acrylate, (meth ) Hexyl acrylate, heptyl (meth) acrylate, octyl (meth) acrylate and 2-ethylhexyl (meth) acrylate, and structural isomers thereof. Furthermore, the alkyl group may have a substituent such as a hydroxyl group, an epoxy group, or a halogen group.

  The binder polymer preferably has a carboxyl group in the molecule from the viewpoint of alkali developability. The binder polymer having a carboxyl group can be produced by radical polymerization of a polymerizable monomer having a carboxyl group and another polymerizable monomer. As the polymerizable monomer having a carboxyl group, methacrylic acid is preferable.

  The binder polymer preferably has styrene or a styrene derivative as a monomer unit from the viewpoint of adhesion and chemical resistance (plating resistance). In order to improve both adhesiveness and peeling properties using styrene or a styrene derivative as a copolymerization component, the binder polymer preferably contains 3 to 30% by mass, more preferably 4 to 28% by mass. It is particularly preferable to contain ~ 27% by mass. If this content is less than 3% by mass, the adhesion tends to decrease, and if it exceeds 30% by mass, the peeling piece tends to be large and the peeling time tends to be long.

  The weight average molecular weight of the binder polymer is preferably 15,000 to 100,000, more preferably 30,000 to 80,000, still more preferably 40,000 to 60,000. If this weight average molecular weight is less than 15000, the photosensitive layer tends to be brittle, and if it exceeds 100000, the remaining filamentous phenomenon occurs and the resolution tends to decrease. In addition, the said weight average molecular weight is measured by gel permeation chromatography, and uses the value converted into standard polystyrene.

  The acid value of the binder polymer is preferably 30 to 200 mgKOH / g, and more preferably 45 to 150 mgKOH / g. When the acid value is less than 30 mgKOH / g, the development time tends to be long, and when it exceeds 200 mgKOH / g, the acidity of the photocured resist with respect to the alkaline developer tends to decrease.

  These binder polymers are used singly or in combination of two or more. Examples of combinations of binder polymers when two or more types are used in combination include, for example, two or more types of binder polymers composed of different copolymerization components, two or more types of binder polymers having different weight average molecular weights, and 2 having different degrees of dispersion. More than one kind of binder polymer can be mentioned. A polymer having a multimode molecular weight distribution described in JP-A No. 11-327137 can also be used.

  As the photopolymerizable compound having an ethylenically unsaturated bond that can be polymerized in the molecule as the component (B), a compound having 4 to 40 carbon oxyalkylene units (alkylene glycol units) in the molecule. It is preferable to include. By containing such a compound as the component (B), compatibility with the (A) binder polymer can be improved.

  Examples of the oxyalkylene unit having 2 to 6 carbon atoms include an oxyethylene unit, an oxypropylene unit, an oxyisopropylene unit, an oxybutylene unit, an oxypentylene unit, and an oxyhexylene unit. The alkylene unit is preferably an oxyethylene unit or an oxyisopropylene unit from the viewpoint of improving resolution and plating resistance.

  Among these photopolymerizable compounds, bisphenol A (meth) acrylate compounds or polyalkylene glycol di (meth) acrylates are particularly preferably used because the effects of the present invention tend to be obtained more reliably. it can.

Preferred examples of the bisphenol A (meth) acrylate compound include compounds represented by the following general formula (I).

In the general formula (I), R ¹ and R ² each independently represent a hydrogen atom or a methyl group, and is preferably a methyl group. In the general formula (I), X ¹ and X ² each independently represent an alkylene group having 2 to 6 carbon atoms, preferably an ethylene group or a propylene group, and more preferably an ethylene group. In the general formula (I), p and q are positive integers selected so that p + q = 4 to 40. The value of p + q is preferably 6 to 34, more preferably 8 to 30, particularly preferably 8 to 28, very preferably 8 to 20, and 8 to 16. Is very preferable, and most preferably 8-12. When the value of p + q is less than 4, the compatibility with the binder polymer as the component (A) is lowered and tends to be peeled off when the photosensitive element is laminated on the circuit forming substrate. On the other hand, if the value of p + q exceeds 40, the hydrophilicity increases, the resist image tends to be peeled off during development, and the plating resistance against solder plating or the like tends to decrease. In either case, the resolution of the photosensitive element tends to decrease.

  Examples of the alkylene group having 2 to 6 carbon atoms include an ethylene group, a propylene group, an isopropylene group, a butylene group, a pentylene group, and a hexylene group. Among these, from the viewpoint of improving resolution and plating resistance, an ethylene group or an isopropylene group is preferable.

  Moreover, the aromatic ring in the said general formula (I) may have a substituent. Examples of the substituent include a halogen atom, an alkyl group having 1 to 20 carbon atoms, a cycloalkyl group having 3 to 10 carbon atoms, an aryl group having 6 to 18 carbon atoms, a phenacyl group, an amino group, and 1 to 10 carbon atoms. Alkylamino group, dialkylamino group having 2 to 20 carbon atoms, nitro group, cyano group, carbonyl group, mercapto group, alkylmercapto group having 1 to 10 carbon atoms, allyl group, hydroxyl group, hydroxyalkyl having 1 to 20 carbon atoms Group, carboxyl group, carboxyalkyl group having 1 to 10 carbon atoms in alkyl group, acyl group having 1 to 10 carbon atoms in alkyl group, alkoxy group having 1 to 20 carbon atoms, alkoxycarbonyl group having 1 to 20 carbon atoms , An alkylcarbonyl group having 2 to 10 carbon atoms, an alkenyl group having 2 to 10 carbon atoms, an N-alkylcarbamoyl group having 2 to 10 carbon atoms, or a complex Groups containing, or an aryl group substituted with these substituents include. The above substituents may form a condensed ring, and a hydrogen atom in these substituents may be substituted with the above substituent such as a halogen atom. When the number of substituents is 2 or more, each of the two or more substituents may be the same or different.

  Examples of the compound represented by the general formula (I) include 2,2-bis (4-((meth) acryloxypolyethoxy) phenyl) propane, 2,2-bis (4-((meth) acrylic). Loxypolypropoxy) phenyl) propane, 2,2-bis (4-((meth) acryloxypolybutoxy) phenyl) propane, 2,2-bis (4-((meth) acryloxypolyethoxypolypropoxy) phenyl) Examples thereof include bisphenol A-based (meth) acrylate compounds such as propane.

  Examples of 2,2-bis (4-((meth) acryloxypolyethoxy) phenyl) propane include 2,2-bis (4-((meth) acryloxydiethoxy) phenyl) propane, 2,2- Bis (4-((meth) acryloxytriethoxy) phenyl) propane, 2,2-bis (4-((meth) acryloxytetraethoxy) phenyl) propane, 2,2-bis (4-((meth)) Acryloxypentaethoxy) phenyl) propane, 2,2-bis (4-((meth) acryloxyhexaethoxy) phenyl) propane, 2,2-bis (4-((meth) acryloxyheptaethoxy) phenyl) propane 2,2-bis (4-((meth) acryloxyoctaethoxy) phenyl) propane, 2,2-bis (4-((meth) acryloxy nonaethoxy) ) Phenyl) propane, 2,2-bis (4-((meth) acryloxydecaethoxy) phenyl) propane, 2,2-bis (4-((meth) acryloxyundecaethoxy) phenyl) propane, 2, 2-bis (4-((meth) acryloxydodecaethoxy) phenyl) propane, 2,2-bis (4-((meth) acryloxytridecaethoxy) phenyl) propane, 2,2-bis (4- ( (Meth) acryloxytetradecaethoxy) phenyl) propane, 2,2-bis (4-((meth) acryloxypentadecaethoxy) phenyl) propane, 2,2-bis (4-((meth) acryloxyhexa) Decaethoxy) phenyl) propane. Of these, 2,2-bis (4- (methacryloxypentaethoxy) phenyl) propane is commercially available as BPE-500 (product name, manufactured by Shin-Nakamura Chemical Co., Ltd.). 2,2-bis (4- (methacryloxypentadecaethoxy) phenyl) propane is commercially available as BPE-1300 (trade name, manufactured by Shin-Nakamura Chemical Co., Ltd.). These may be used alone or in combination of two or more.

  Examples of 2,2-bis (4-((meth) acryloxypolyethoxypolypropoxy) phenyl) propane include 2,2-bis (4-((meth) acryloxydiethoxyoctapropoxy) phenyl) propane, Examples include 2,2-bis (4-((meth) acryloxytetraethoxytetrapropoxy) phenyl) propane and 2,2-bis (4-((meth) acryloxyhexaethoxyhexapropoxy) phenyl) propane. These are used singly or in combination of two or more.

Preferred examples of the polyalkylene glycol di (meth) acrylate include compounds represented by the following general formula (II).

In the general formula (II), R ³ and R ⁴ each independently represent a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, and is preferably a methyl group. In the general formula ^{(II), Y 1, Y} 2 and ^{Y 3} is an alkylene group having 2 to 6 carbon atoms is preferably an ethylene group or a propylene group. In the general formula (II), s, t and u are integers of 0 to 30 selected so that s + t + u = 4 to 40. The value of s + t + u is preferably 5-30, more preferably 8-23, and particularly preferably 10-15. If the value of s + t + u is less than 4, the boiling point of the compound tends to decrease, and the odor of the photosensitive layer 20 tends to increase. On the other hand, if s + t + u exceeds 40, the concentration of photoreactive sites per unit weight tends to be low, and there is a tendency that practical sensitivity cannot be obtained.

In addition, the oxyalkylene unit (— (Y ¹ —O) _s —, — (Y ² —O) _t —, and — (Y ³ —O) _u —) in the general formula (II) is, for example, oxy When including a plurality of ethylene units and oxypropylene units, the plurality of oxyethylene units and oxypropylene units do not need to be continuously present in blocks, and may be present randomly.

  Furthermore, when the oxyalkylene unit is an oxyisopropylene unit, the secondary carbon of the propylene group may be bonded to the oxygen atom, or the primary carbon may be bonded to the oxygen atom.

  Preferred examples of the compound represented by the general formula (II) include a compound represented by the following general formula (III), a compound represented by the following general formula (IV), and a compound represented by the following general formula (V). The compound which is made is mentioned. These are used singly or in combination of two or more.

式（ＩＩＩ）中、Ｒ^３及びＲ^４はそれぞれ独立に水素原子又は炭素数１〜３のアルキル基を示し、ＥＯはオキシエチレン単位を示し、ＰＯはオキシプロピレン単位を示し、ｍ^１、ｍ^２及びｎ^１はｍ^１＋ｍ^２＋ｎ^１＝４〜４０となるように選ばれる１〜３０の整数を示す。

In Formula (III), R ³ and R ⁴ each independently represent a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, EO represents an oxyethylene unit, PO represents an oxypropylene unit, m ¹ , m ² And n ¹ represents an integer of 1 to 30 selected so that m ¹ + m ² + n ¹ = 4 to 40.

式（ＩＶ）中、Ｒ^３及びＲ^４は水素原子又は炭素数１〜３のアルキル基を示し、ＥＯはオキシエチレン単位を示し、ＰＯはオキシプロピレン単位を示し、ｍ^３、ｎ^２及びｎ^３はｍ^３＋ｎ^２＋ｎ^３＝４〜４０となるように選ばれる１〜３０の整数を示す。

In formula (IV), R ³ and R ⁴ represent a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, EO represents an oxyethylene unit, PO represents an oxypropylene unit, m ³ , n ² and n ³ Represents an integer of 1 to 30 selected so that m ³ + n ² + n ³ = 4 to 40.

式（Ｖ）中、Ｒ^３及びＲ^４は水素原子又は炭素数１〜３のアルキル基を示し、ＥＯはオキシエチレン単位を示し、ＰＯはオキシプロピレン単位を示し、ｍ^４及びｎ^４はｍ^４＋ｎ^４＝４〜４０となるように選ばれる１〜３０の整数を示す。

In formula (V), R ³ and R ⁴ represent a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, EO represents an oxyethylene unit, PO represents an oxypropylene unit, and m ⁴ and n ⁴ represent m ^4. + shows the 30 integer selected to ⁿ 4 = 4 to 40 and so as.

  Examples of the alkyl group having 1 to 3 carbon atoms in the general formula (III), the general formula (IV), and the general formula (V) include a methyl group, an ethyl group, an n-propyl group, and an isopropyl group.

In addition, the total number of repeating oxyethylene units (m ¹ + m ² , m ³ and m ⁴ ) in the above general formula (III), general formula (IV) and general formula (V) is each independently an integer of 1 to 30 Is preferable, an integer of 1 to 10 is more preferable, an integer of 4 to 9 is further preferable, and an integer of 5 to 8 is particularly preferable. If the number of repetitions exceeds 30, the tent reliability and the resist shape tend to deteriorate.

The total number of repeating oxypropylene units (n ¹ , n ² + n ³ and n ⁴ ) in the above general formula (III), general formula (IV) and general formula (V) is an integer of 1 to 30 each independently. It is preferably an integer of 5 to 20, more preferably an integer of 8 to 16, and particularly preferably an integer of 10 to 14. If the number of repetitions exceeds 30, the resolution deteriorates and sludge tends to be generated.

Specific examples of the compound represented by the general formula (III) include, for example, vinyl in which R ³ and R ⁴ are a methyl group, m ¹ + m ² = 4 (average value), and n ¹ = 12 (average value). Compound (manufactured by Hitachi Chemical Co., Ltd., trade name: FA-023M) and the like.

Specific examples of the compound represented by the general formula (IV) include, for example, vinyl in which R ³ and R ⁴ are methyl groups, m ³ = 6 (average value), and n ² + n ³ = 12 (average value). Compound (manufactured by Hitachi Chemical Co., Ltd., trade name: FA-024M) and the like.

Specific examples of the compound represented by the general formula (V) include a vinyl compound in which R ³ and R ⁴ are hydrogen atoms, m ⁴ = 1 (average value), and n ⁴ = 9 (average value) ( Shin-Nakamura Chemical Co., Ltd., sample name: NK ester HEMA-9P) and the like.

  In addition, these are used individually by 1 type or in combination of 2 or more types.

  In addition to the photopolymerizable compound having an ethylenically unsaturated bond polymerizable in the molecule as described above, the component (B) further contains a photopolymerizable compound having another ethylenically unsaturated bond. It is preferable to contain. Examples of other photopolymerizable compounds having an ethylenically unsaturated bond include nonylphenoxy such as nonylphenoxypolyethyleneoxy (meth) acrylate, nonylphenoxypolypropyleneoxy (meth) acrylate, and nonylphenoxypolyethyleneoxypolypropyleneoxy (meth) acrylate. Polyalkyleneoxy (meth) acrylate, γ-chloro-β-hydroxypropyl-β ′-(meth) acryloyloxyethyl-o-phthalate, β-hydroxyalkyl-β ′-(meth) acryloyloxyalkyl-o-phthalate, etc. Phthalic acid compounds, and (meth) acrylic acid alkyl esters.

  Moreover, you may make the photosensitive resin composition of this invention contain photopolymerizable compounds other than the photopolymerizable compound mentioned above. Examples of such photopolymerizable compounds include compounds obtained by reacting a glycidyl group-containing compound with an α, β-unsaturated carboxylic acid, and urethane monomers such as (meth) acrylate compounds having a urethane bond in the molecule. Can be mentioned.

  Examples of the photopolymerization initiator (C) include N, N′-tetraalkyl-4,4′- such as benzophenone; N, N′-tetramethyl-4,4′-diaminobenzophenone (Michler ketone). Fragrance such as diaminobenzophenone; 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) -butanone-1, 2-methyl-1- [4- (methylthio) phenyl] -2-morpholino-propanone-1 Group ketones; quinone compounds such as alkyl anthraquinones; benzoin ether compounds such as benzoin alkyl ethers; benzoin compounds such as benzoin and alkyl benzoin; benzyl derivatives such as benzyldimethyl ketal; 2- (o-chlorophenyl) -4,5-diphenylimidazole Dimer, 2- (o-chlorophenyl) -4, -Di (methoxyphenyl) imidazole dimer, 2- (o-fluorophenyl) -4,5-diphenylimidazole dimer, 2- (o-methoxyphenyl) -4,5-diphenylimidazole dimer, 2 2,4,5-triarylimidazole dimers such as-(p-methoxyphenyl) -4,5-diphenylimidazole dimer; 9-phenylacridine, 1,7-bis (9,9'-acridinyl) Examples include acridine derivatives such as heptane; N-phenylglycine, N-phenylglycine derivatives, and coumarin compounds. In addition, in the 2,4,5-triarylimidazole dimer, the aryl group substituents of two 2,4,5-triarylimidazoles may give the same and symmetric compounds, or differently asymmetric Such compounds may be provided. Among these, 2,4,5-triarylimidazole dimer is preferable from the viewpoint of improving adhesion and sensitivity. These are used individually by 1 type or in combination of 2 or more types.

  The blending amount of the binder polymer as component (A) is preferably 40 to 70 parts by mass, and 50 to 60 parts by mass with respect to 100 parts by mass as the total of component (A) and component (B). Is more preferable. If the blending amount is less than 40 parts by mass, the photocured product tends to be brittle, and if it exceeds 70 parts by mass, the resolution and photosensitivity tend to be insufficient.

  (B) The compounding quantity of the photopolymerizable compound which has an ethylenically unsaturated bond polymerizable in the molecule | numerator which is a component is 30-60 mass with respect to 100 mass parts of total amounts of (A) component and (B) component. Part is preferable, and 40 to 50 parts by mass is more preferable. If the blending amount is less than 30 parts by mass, resolution and photosensitivity tend to be insufficient, and if it exceeds 60 parts by mass, the photocured product tends to be brittle.

  The blending amount of the photopolymerization initiator (C) is preferably 0.1 to 20 parts by mass with respect to 100 parts by mass as the total of the components (A) and (B), and is 0.2 to It is more preferable that it is 10 mass parts. If the blending amount is less than 0.1 parts by mass, the photosensitivity tends to be insufficient, and if it exceeds 20 parts by mass, the light absorption on the surface of the photosensitive resin composition increases during the exposure, and the internal Photocuring tends to be inadequate.

  In addition, the photosensitive resin composition may include a photopolymerizable compound (oxetane compound or the like) having at least one cationically polymerizable cyclic ether group in the molecule, a cationic polymerization initiator, a dye such as malachite green, if necessary. , Photochromic agents such as tribromophenylsulfone and leucocrystal violet, thermochromic inhibitors, plasticizers such as p-toluenesulfonamide, pigments, fillers, antifoaming agents, flame retardants, stabilizers, adhesion-imparting agents, You may contain additives, such as a leveling agent, peeling promoter, antioxidant, a fragrance | flavor, an imaging agent, and a thermal crosslinking agent. These are used singly or in combination of two or more. These additives may be contained in an amount of about 0.01 to 20 parts by mass per 100 parts by mass of the total amount of the component (A) and the component (B) as long as the object of the present invention is not impaired.

  The photosensitive resin composition is dissolved in a solvent such as methanol, ethanol, acetone, methyl ethyl ketone, methyl cellosolve, ethyl cellosolve, toluene, N, N-dimethylformamide and propylene glycol monomethyl ether, or a mixed solvent thereof, as necessary. Thus, it can be prepared as a solution having a solid content of about 30 to 60% by mass.

  The photosensitive layer 20 in the photosensitive element 1 of the present invention can be formed by applying the above-described photosensitive resin composition on the support film 10 and removing the solvent. Here, as a coating method, for example, a known method such as a roll coater, a comma coater, a gravure coater, an air knife coater, a die coater, or a bar coater can be employed. Moreover, the removal of a solvent can be performed by processing for about 5 to 30 minutes at the temperature of 70-150 degreeC, for example. The amount of the remaining organic solvent in the photosensitive layer 20 is preferably 2% by mass or less from the viewpoint of preventing the organic solvent from diffusing in a later step.

  The thickness of the photosensitive layer 20 thus formed is preferably 1 to 100 μm after drying. If this thickness is less than 1 μm, problems tend to occur when the photosensitive layer is laminated on the circuit forming substrate, and the production yield of the printed wiring board tends to decrease. On the other hand, when the thickness exceeds 100 μm, the resolution of the photosensitive layer 20 deteriorates, and it tends to be difficult to produce a high-density printed wiring board.

  The photosensitive element 1 may include a protective film (not shown) on the main surface of the photosensitive layer 20 opposite to the main surface in contact with the support film 10. As the protective film, it is preferable to use a film in which the adhesive force between the photosensitive layer 20 and the protective film is smaller than the adhesive force between the photosensitive layer 20 and the support film 10, and a low fish. It is preferable to use an eye film. Specific examples include inert polyolefin films such as polyethylene and polypropylene. From the viewpoint of peelability from the photosensitive layer 20, a polyethylene film is preferable. Although the thickness of a protective film changes with uses, it is preferable that it is about 1-100 micrometers.

  The photosensitive element 1 may further include an intermediate layer or a protective layer such as a cushion layer, an adhesive layer, a light absorption layer, and a gas barrier layer in addition to the support film 10, the photosensitive layer 20, and the protective film.

  The photosensitive element 1 of the present embodiment may be stored, for example, as it is or in a state where a protective film further laminated on the photosensitive layer 20 is wound around a cylindrical core. At this time, it is preferable that the support film 10 is wound into a roll shape so as to become an outer layer again. Moreover, it is preferable to install an end face separator on the end face of the photosensitive element 1 wound up in a roll shape from the viewpoint of end face protection, and it is preferable to install a moisture-proof end face separator from the viewpoint of edge fusion resistance. Further, as a packing method, it is preferable to wrap and package in a black sheet with low moisture permeability.

  Examples of the core material include plastics such as polyethylene resin, polypropylene resin, polystyrene resin, polyvinyl chloride resin, and ABS resin (acrylonitrile-butadiene-styrene copolymer).

(Method for forming resist pattern)
The resist pattern forming method of the present embodiment includes a laminating step in which the photosensitive element 1 is laminated on a circuit forming substrate in the order of the photosensitive layer 20 and the support film 10, and actinic rays are passed through the support film 10. This is a method including an exposure step of irradiating a predetermined portion of the photosensitive layer 20 to form a photocured portion on the photosensitive layer 20 and a developing step of removing a portion of the photosensitive layer 20 other than the photocured portion.

  In the laminating step, as a method of laminating the photosensitive layer 20 on the circuit forming substrate, when a protective film is present on the photosensitive layer 20, the photosensitive layer 20 is removed by 70 to 70 after removing the protective film. The method of laminating | stacking by crimping | bonding to a circuit formation board | substrate with the pressure of about 0.1-1 Mpa etc., heating at about 130 degreeC is mentioned. In this lamination step, lamination can also be performed under reduced pressure. The surface on which the circuit forming substrate is laminated is usually a metal surface, but is not particularly limited. Further, in order to further improve the stackability, a pre-heat treatment of the circuit forming substrate may be performed.

  Next, a photomask having a negative or positive mask pattern is aligned with and closely adhered to the second main surface 14 of the support film 10 with respect to the photosensitive layer 20 that has been laminated in the above-described lamination step. Thereafter, in the exposure step, the photosensitive layer 20 is irradiated with an actinic ray in an image form through the support film 10 to form a photocured portion on the photosensitive layer 20. As the light source of the actinic light, a known light source such as a carbon arc lamp, a mercury vapor arc lamp, a high pressure mercury lamp, a xenon lamp, or the like that effectively emits ultraviolet rays or visible light is used. It is also used for laser direct drawing exposure.

  Next, after the exposure step, the photomask is peeled from the support film 10. Further, the support film 10 is peeled off from the photosensitive layer 20. Next, in the exposure process, the unexposed portion (photocured portion) of the photosensitive layer 20 is removed and developed by wet development with a developing solution such as an alkaline aqueous solution, aqueous developer, organic solvent, dry development, etc., and a resist pattern is produced. can do.

  Examples of the alkaline aqueous solution include a dilute solution of 0.1 to 5 wt% sodium carbonate, a dilute solution of 0.1 to 5 wt% potassium carbonate, a dilute solution of 0.1 to 5 wt% sodium hydroxide, and the like. . The pH of the alkaline aqueous solution is preferably in the range of 9 to 11, and the temperature is adjusted according to the developability of the photosensitive layer 20. Further, a surfactant, an antifoaming agent, an organic solvent, or the like may be mixed in the alkaline aqueous solution. Examples of the development method include a dip method, a spray method, brushing, and slapping.

Moreover, as a process after a development process, you may further harden a resist pattern by performing about 60-250 degreeC heating or about 0.2-10 J / cm < ² > exposure as needed.

(Printed wiring board manufacturing method)
The printed wiring board manufacturing method of the present embodiment is performed by etching or plating the circuit forming substrate on which the resist pattern is formed by the resist pattern forming method. Here, etching or plating of the circuit forming substrate is performed by etching or plating the surface of the circuit forming substrate by a known method using the developed resist pattern as a mask.

  As an etching solution used for etching, for example, a cupric chloride solution, a ferric chloride solution, an alkaline etching solution, or the like can be used.

  Examples of plating include copper plating, solder plating, nickel plating, and gold plating.

  After etching or plating, the resist pattern can be peeled off with a stronger alkaline aqueous solution than the alkaline aqueous solution used for development, for example. As this strongly alkaline aqueous solution, for example, a 1 to 10% by weight sodium hydroxide aqueous solution, a 1 to 10% by weight potassium hydroxide aqueous solution and the like are used. Moreover, as a peeling system, an immersion system, a spray system, etc. are mentioned, for example. The printed wiring board on which the resist pattern is formed may be a multilayer printed wiring board or may have a small diameter through hole.

  In addition, when plating is performed on a circuit forming substrate including an insulating layer and a conductor layer formed on the insulating layer, it is necessary to remove the conductor layer other than the pattern. As this removal method, for example, a method of lightly etching after removing the resist pattern, or performing solder plating after the above plating, and then masking the wiring portion with solder by peeling off the resist pattern, and then conducting layer The method etc. which process using the etching liquid which can etch only are mentioned.

  As described above, according to the photosensitive element, the resist pattern forming method, and the printed wiring board manufacturing method of the present embodiment described above, the photosensitive element 1 has a haze of 1.0% or less as the support film 10. I have. As a result, when the photosensitive layer 20 is irradiated with actinic rays through the support film 10, a photocured portion can be formed in the photosensitive layer 20 with sufficiently excellent resolution and photosensitivity. Therefore, since the resolution of the resist pattern and the printed circuit board obtained are sufficiently excellent, the circuit can be further densified.

In addition, the photosensitive element 1 includes a support film 10 having a surface resistivity of 10 ¹³ Ω or less. Thereby, first, in the photosensitive element 1 wound up in roll shape, sticking with the support body film 10, the photosensitive layer 20, or a protective film can be prevented. Moreover, the adhesion of foreign matter such as dust and dirt to the second main surface 14 of the support film 10 is sufficiently suppressed. Therefore, when the photomask is brought into close contact with the second main surface 14 of the support film 10, it is possible to sufficiently prevent the obstruction of the close contact due to foreign matter. Furthermore, it is possible to sufficiently prevent patterning defects caused by irradiation with actinic rays through the foreign matter that may occur when the foreign matter adheres. Moreover, the phenomenon that a photomask adheres strongly to the support body film 10 can also be fully suppressed. Thereby, since alignment of a photomask and peeling removal from the support body film 10 of a photomask can be performed easily, workability | operativity etc. improve. As a result, the production efficiency of the printed wiring board can be improved and the yield can be increased.

  The present invention has been described in detail based on the embodiments. However, the present invention is not limited to the above embodiment. The present invention can be variously modified without departing from the gist thereof.

  Hereinafter, preferred examples of the present invention will be described in more detail, but the present invention is not limited to these examples.

(Example 1 and Comparative Examples 1-2)
(Preparation of solution of photosensitive resin composition)
Each component shown in the following Table 1 was blended to prepare a solution of the photosensitive resin composition.

(Production of photosensitive element)
Next, a polyethylene terephthalate (hereinafter referred to as “PET”) film shown in Table 2 was prepared as a support film for the photosensitive element. Table 2 shows the haze of each PET film. The haze of the support film is a value measured according to JIS K 7105. Each of these support films had a thickness of 16 μm.

  Next, the above-mentioned photosensitive resin composition solution was applied onto each PET film so as to have a uniform thickness, and dried for 2 minutes in a hot air convection dryer at 100 ° C. to remove the solvent. After drying, the photosensitive layer was covered with a protective film made of polyethylene (manufactured by Tamapoly, trade name “NF-15”, thickness 20 μm) to obtain a photosensitive element. The thickness of the photosensitive layer after drying was 25 μm in all cases.

(Production of laminate)
First, the copper surface of a copper-clad laminate (made by Hitachi Chemical Co., Ltd., trade name “MLC-E-679”), which is a glass epoxy material in which copper foil (thickness: 35 μm) is laminated on both sides, is equivalent to # 600. Polishing was performed using a polishing machine having a brush (manufactured by Sankeisha), washed with water, and then dried with an air stream. The obtained copper-clad laminate was heated to 80 ° C., and the photosensitive element was laminated so that the photosensitive layer was in contact with the copper surface while peeling off the protective film. Thus, a laminate was obtained in which the copper clad laminate, the photosensitive layer, and the support film were laminated in this order. Lamination was performed using a 120 ° C. heat roll at a pressure of 0.4 MPa and a roll speed of 1.5 m / min. These laminates were used as test pieces in the following tests.

(Photosensitivity measurement test)
The specimen support film, with placing a Stouffer 21-step tablet as a negative, exposure machine with a high-pressure mercury lamp (the oak's trade name "EXM-1201"), 60 mJ / cm ² The photosensitive layer was exposed to an irradiation energy amount of. Next, the support film was peeled off, and a 1% by mass aqueous sodium carbonate solution at 30 ° C. was sprayed for 60 seconds to remove the unexposed portion and develop. And the photosensitivity of the photosensitive resin composition was evaluated by measuring the number of steps of the step tablet of the photocured film formed on the copper clad laminate. The results are shown in Table 2. The photosensitivity is indicated by the number of steps of the step tablet, and the higher the number of steps of the step tablet, the higher the photosensitivity.

(Resolution measurement test)
In order to investigate the resolution, a photo tool having a stove 21-step tablet and a photo tool having a wiring pattern having a line width / space width of 10/10 to 100/100 (unit: μm) as a negative for resolution evaluation were tested. Using an exposure machine having a high pressure mercury lamp lamp in close contact with the piece of support film, the exposure was performed with an irradiation energy amount such that the number of remaining step stages after development of the stove 21-step tablet was 8.0. Next, the support film was peeled off, and a 1% by mass aqueous sodium carbonate solution at 30 ° C. was sprayed for 60 seconds to remove the unexposed portion and develop. Here, the resolution was evaluated based on the smallest value (unit: μm) of the space width between the line widths in which the unexposed portion could be removed cleanly by the development process. The results are shown in Table 2. Note that the smaller the numerical value, the better the evaluation of resolution.

(Static generation test)
First, the laminate was wound into a roll shape with the support film on the outside. Then, the laminated body wound up in roll shape was pulled out from the edge part. And the static electricity generation amount in the support body film immediately after drawing | extracting out was measured using the static electricity measuring device (The Simco Japan company make, brand name "FMX-002"). In addition, the static electricity generation amount of the support film was measured on the main surface that was in contact with the protective film in the wound state. The amount of static electricity generated was measured as a charged potential (unit: kV). The results are shown in Table 2.

It is a schematic cross section which shows suitable one Embodiment of the photosensitive element which concerns on embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Photosensitive element, 10 ... Support film, 12 ... 1st main surface, 14 ... 2nd main surface, 20 ... Photosensitive layer.

Claims (3)

A photosensitive element comprising a support film and a layer made of a photosensitive resin composition provided on the first main surface of the support film, wherein the haze of the support film is 1.0% or less. And the surface resistivity of the second main surface opposite to the first main surface of the support film is 10 ¹³ Ω or less.   The photosensitive element according to claim 1, wherein the support film is a film containing, as a main component, one or more polymers selected from the group consisting of polyethylene terephthalate, polypropylene, polyethylene, and polyester. The photosensitive resin composition according to claim 1, wherein the photosensitive resin composition comprises a binder polymer, a photopolymerizable compound having an ethylenically unsaturated bond polymerizable in a molecule, and a photopolymerization initiator. element.

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