JP2005031523A - Photosensitive film and method for manufacturing printed wiring board using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a photosensitive film which can be tightly adhered, in particular, to a rugged part of a substrate surface without generating a gap and which does not produce splits or resin chips when manufactured, and to provide a method for manufacturing a printed wiring board by using the film. <P>SOLUTION: The photosensitive film comprises a supporting layer, a cushion layer formed on the supporting layer, and a photosensitive layer formed on the cushion layer. The cushion layer comprises a resin having ≤1,000% breaking extension and ≤10 MPa tensile modulus of elasticity. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a photosensitive film and a method for producing a printed wiring board using the same.

  Conventionally, in the field of manufacturing printed wiring boards, a photosensitive film has been used to form a resist film used for etching or plating. This photosensitive film is usually formed by applying a photosensitive composition on a support layer such as a base film and drying it, and then forming a protective layer such as a protective film on the photosensitive layer. It is obtained by forming.

  Formation of a resist film using such a conventional photosensitive film is generally performed as follows. First, the photosensitive film from which the protective layer has been peeled is disposed so as to be laminated on a circuit forming substrate (hereinafter simply referred to as a substrate) in the order of the photosensitive layer and the support layer. Then, the photosensitive film is pressure-bonded (laminated) to the substrate by applying pressure from above the support layer using a heating roll. Subsequently, a negative mask for pattern formation is disposed on the support layer, and the photosensitive layer is irradiated with actinic rays for exposure through the negative mask. As a result, the exposed portion of the photosensitive layer is photocured, and thereafter, after the negative mask is removed, and development is performed after the support layer is peeled off, a photosensitive layer having the same pattern as the pattern of the negative mask can be obtained as a resist film. it can.

  In order to maintain the tensile strength of the photosensitive film to some extent, the base film used as the support layer usually has a tensile strength of 5% elongation load per unit width at 80 ° C. of 100 g / mm or more in the longitudinal direction of the film. (For example, a PET film) having a certain thickness is used.

  The photosensitive layer is made of a photosensitive composition that changes the physical properties of the irradiated portion when irradiated with actinic rays such as ultraviolet rays, and various compositions are used as necessary. The photosensitive layer can have various thicknesses as required. Particularly in recent years, the thickness of the photosensitive layer tends to be reduced in order to meet the demand for higher density and higher resolution of the printed wiring board.

  Furthermore, the surface of the substrate is usually uneven due to the presence of dents and the like.

  By the way, when the photosensitive film is pressure-bonded on the substrate, if a non-adhered portion is formed between the substrate and the photosensitive film, a gap is formed on the surface portion of the substrate that should originally be in close contact with the resist film. Will occur. As a result, when etching is performed later, the etching solution erodes the conductor on the substrate, resulting in inconvenience such as chipping or disconnection of the conductor. Further, when plating is performed later, inconveniences such as short-circuiting by forming a plating film between the circuit wirings occur. Therefore, it is necessary that the substrate and the photosensitive film are in close contact with each other without any gap.

  However, as described above, when the support layer has a somewhat higher tensile strength and a certain thickness, and the photosensitive layer becomes thinner, the flexibility as the photosensitive film is lowered. Furthermore, if there is an uneven portion on the surface of the substrate, the substrate and the photosensitive film are not in close contact over the entire surface to be in close contact, and a gap is likely to occur partially. This is because even when the photosensitive film is pressed against the substrate, the flexibility of the photosensitive layer is insufficient, so that the photosensitive layer is not sufficiently embedded in the entire uneven portion present on the substrate surface. In the present specification, the property that the photosensitive layer is embedded in close contact with the entire concave and convex portion with respect to the concave and convex portion existing on the substrate surface is referred to as “embedding followability” or simply “following capability”. Called.

  In order to solve such a problem, various means have been proposed. For example, Patent Documents 1 and 2 propose a lamination method intended to obtain a very good adhesion between the substrate and the photosensitive film by laminating the photosensitive film after applying water to the substrate. ing.

  Further, in Patent Document 3, after forming a bonding intermediate layer by laminating a liquid resin on a substrate, forming a photoresist intended to eliminate incomplete bonding by laminating a photosensitive film. A method has been proposed.

  Furthermore, Patent Documents 4 and 5 propose a laminating method and apparatus intended to bond them without any remaining bubbles between the substrate and the photosensitive film by laminating under reduced pressure using a vacuum laminator. Has been.

  Furthermore, in Patent Document 6, by providing a thermoplastic resin layer, an intermediate layer, and a photosensitive layer in this order on a base film (support layer), transfer of the photosensitive layer to the substrate due to air bubbles and steps on the surface of the support layer, etc. A photosensitive film intended to prevent defects has been proposed.

  Further, Patent Document 7 proposes a photosensitive film intended to improve the followability to the unevenness of the surface of the substrate by sequentially providing a cushion layer, a photosensitive layer and a carver film on the base film. .

JP 57-21890 A JP-A-57-21891 JP-A-52-154363 Japanese Patent Laid-Open No. 51-63702 Japanese Patent Publication No.53-31670 JP-A-5-80503 JP 2003-5364 A

  However, the present inventors have made a detailed study on the photosensitive films and the like described in Patent Documents 1 to 7, and for example, in the lamination method described in Patent Documents 1 and 2, a thin layer of water is used. It is necessary to clean the substrate surface in order to adhere uniformly to the substrate surface, and when the substrate has a small-diameter through-hole, the water present in the through-hole easily reacts with the photosensitive layer. It has been found that there are problems such as developing problems.

  Further, in the method for forming a photoresist described in Patent Document 3, when a small-diameter through hole is provided in the substrate, there is a problem that the developability and peelability of the resist film in the small-diameter through hole are reduced. It was found.

  Furthermore, the vacuum laminator described in Patent Documents 4 and 5 and the laminating method using the vacuum laminator reduce the followability of the photosensitive layer with respect to the concavo-convex portions existing on the substrate surface when the photosensitive layer is thinned. It was found that there was a partial gap between the film and the photosensitive film.

  In addition, the photosensitive film described in Patent Document 6 cannot obtain a high resolution because a thermoplastic resin layer and an intermediate layer exist between the photosensitive layer and the negative mask during exposure. Was found.

  Furthermore, since the photosensitive film described in Patent Document 7 cannot be cut cleanly due to, for example, the flexibility of the resin contained in the cushion layer, a crease is formed on the cut surface and / or the cut surface. It was found that a section (resin piece) of the resin was generated. For example, the groin portion and the resin piece cause the following inconvenience.

  That is, the photosensitive film is cut out in a roll shape in accordance with the width (length) of the substrate from the original film of the photosensitive film during the production (slit process). A roll-side end surface (the cut surface) of the photosensitive film wound up after the slitting process may have a crest portion or the resin piece may adhere. If the resin piece or the resin piece produced by peeling off the ridge during the subsequent process adheres to the substrate when the photosensitive film is placed on the substrate, even if it is slight, a resist film It affects the formation or development.

  Moreover, the photosensitive film is cut out to the same size (cross-sectional area) as the arrangement surface of the substrate before being arranged on the substrate. Even if only a small amount of the raised portion occurs at this time, it prevents the photosensitive film from being pressed onto the substrate when the photosensitive film is placed on the substrate, and the photosensitive film and the substrate are pressed against each other. Therefore, it is necessary to suppress the occurrence of such ridges as much as possible. Further, even if the resin piece generated at this time is small, it adheres to the substrate or the photosensitive layer when the support layer and the cushion layer are peeled off from the photosensitive layer, thereby affecting the formation or development of the resist film. Effect. Therefore, it is necessary to suppress the generation of such resin pieces as much as possible.

  As described above, none of the inventions described in the cited documents 1 to 7 can provide a printed wiring board having high density and high resolution. Therefore, the present invention has been made in view of the above circumstances, and in order to obtain a printed wiring board having a high density and a high resolution, in particular, it adheres without causing a gap in the uneven portion of the substrate surface, and is manufactured. It is an object of the present invention to provide a photosensitive film that does not sometimes cause a crease or a resin piece and a method for producing a printed wiring board using the same.

  As a result of intensive studies to achieve the above object, the present inventors have controlled the specific physical properties of the resin contained in the cushion layer contained in the photosensitive film, thereby providing the photosensitive layer contained in the photosensitive film. It was found that the following property of the substrate unevenness portion was maintained and the photosensitive film could be cut cleanly, and the present invention was completed.

  That is, the photosensitive film of the present invention is a photosensitive film comprising a support layer, a cushion layer formed on the support layer, and a photosensitive layer formed on the cushion layer. %, And a resin having a tensile modulus of elasticity of 10 MPa or less.

  Thereby, the photosensitive film is arranged on the substrate with the surface of the photosensitive layer opposite to the surface in contact with the cushion layer facing the substrate, and when pressed in the substrate direction, Even if there are uneven portions, the surface of the photosensitive layer on the substrate side is in close contact with the substrate surface, and no gap is formed between them. Therefore, even if the photosensitive layer included in the photosensitive film is thinner than the conventional one, the followability of the photosensitive film to the substrate surface is ensured, so that the photosensitive film has higher resolution and higher density printed wiring. It can also be applied to the manufacture of plates.

  In addition, even when the photosensitive film is cut during the slitting process or the like, the photosensitive film is sufficiently suppressed from having a ridged portion on the cut surface, and / or a resin piece is sufficiently generated from the cut surface. It is suppressed. Therefore, when the photosensitive film is pressure-bonded to the substrate, the above-mentioned ridges and resin pieces do not interfere with the pressure-bonding.

  For the first time, this photosensitive film is provided with a photosensitive layer having the above-mentioned characteristics among various characteristics. Can be realized simultaneously. That is, even if the resin contained in the cushion layer has a breaking elongation of 1000% or less, if the tensile elastic modulus is not more than 10 MPa, the followability of the photosensitive film to the uneven portion of the substrate surface is lowered. On the contrary, even if it has a tensile elastic modulus of 10 MPa or less, if it does not have an elongation at break of 1000% or less, a crease or a resin piece occurs on the cut surface of the photosensitive film. Sometimes.

  Further, by using the photosensitive film of the present invention, it is not necessary to attach a thin layer of water to the substrate surface, so that there is no problem in developability. Furthermore, even if the substrate has a small-diameter through hole, the developability and peelability of the resist film are not deteriorated.

  In the photosensitive film of the present invention, the interlayer adhesive force between the cushion layer and the photosensitive layer is preferably smaller than the interlayer adhesive force between the support layer and the cushion layer. Thereby, when peeling a cushion layer from a photosensitive film, a photosensitive layer does not accompany the cushion layer and peels.

  Further, the photosensitive layer contains (A) a binder polymer, (B) a photopolymerizable compound having at least one polymerizable ethylenically unsaturated bond in the molecule, and (C) a photopolymerization initiator. Preferably it consists of a photosensitive resin composition. Such a photosensitive resin composition imparts excellent photosensitivity, developability, chemical resistance, flexibility, mechanical strength and the like to the photosensitive layer in the method for producing a printed wiring board. Therefore, in the production of a printed wiring board, this photosensitive film can laminate a photosensitive layer on a substrate with a high yield, and is useful for further increasing the density of the printed wiring board.

  Further, the method for producing a printed wiring board of the present invention includes a laminating step in which the above-described photosensitive film is laminated on a substrate in the order of a photosensitive layer, a cushion layer, and a support layer; An exposure process for irradiating a predetermined portion to form a photocured part on the photosensitive layer, a peeling process for removing the support layer and the cushion layer from the photosensitive film, and removing the photosensitive layer other than the photocured part And a developing step. At this time, the exposure step can be performed after the laminating step and before the peeling step, and in that case, an actinic ray is irradiated to a predetermined portion of the photosensitive layer through the support layer and the cushion layer. .

  Furthermore, in another method for producing a printed wiring board according to the present invention, the exposure step in the method for producing a printed wiring board may be performed after the peeling step and before the developing step. In this case, the actinic ray is directly irradiated onto the photosensitive layer in the exposure step.

  Since these printed wiring board manufacturing methods use the above-described photosensitive film, they have excellent adhesion between the substrate and the photosensitive film, and do not produce resin pieces or the like. Etching and the like can be performed, and the density of the printed wiring board can be easily realized.

  According to the present invention, there is provided a photosensitive film that closely adheres to an uneven portion on the surface of a substrate without causing a gap, and that does not generate a crease or a resin piece during production, and a method for producing a printed wiring board using the same. can do.

  Hereinafter, preferred embodiments of the present invention will be described in detail. In the present invention, “(meth) acrylic acid” means “acrylic acid” and its corresponding “methacrylic acid”, and “(meth) acrylate” means “acrylate” and its corresponding “methacrylate”. “(Meth) acryloyl” means “acryloyl” and its corresponding “methacryloyl”, and “(meth) acryloxy” means “acryloxy” and its corresponding “methacryloxy”.

  The photosensitive film of the present invention is a photosensitive film comprising a support layer, a cushion layer formed on the support layer, and a photosensitive layer formed on the cushion layer, and the cushion layer is 1000%. It contains a resin having the following elongation at break and a tensile modulus of 10 MPa or less.

(Support layer)
Since the support layer according to the present invention uses the support of the photosensitive film as a main purpose, it is not particularly limited as long as the main purpose can be achieved. Therefore, for example, a base film made of a polymer having heat resistance and solvent resistance, such as polyethylene terephthalate, polypropylene, polyethylene, and polyester can be used.

  The support layer preferably has a thickness of 2 to 100 μm, more preferably 5 to 20 μm, and particularly preferably 8 to 16 μm. If the thickness is less than 2 μm, the support layer tends to be broken when the support layer or the cushion layer is peeled off, and if it exceeds 100 μm, the followability of the photosensitive film to the substrate surface tends to be lowered. Moreover, the photosensitive film can have sufficient tensile strength as this thickness is 8-16 micrometers, Furthermore, the cost spent on a support layer can fully be suppressed.

  Furthermore, when exposing a photosensitive film without peeling a support layer, it is preferable that the haze of a support layer is 0.001-5.0, and it is more preferable that it is 0.001-2.0, It is especially preferable that it is 0.01-1.8. When this haze exceeds 2.0, the resolution tends to decrease. The haze is measured according to JIS K 7105, and can be measured with a commercially available turbidimeter such as NDH-1001DP (trade name, manufactured by Nippon Denshoku Industries Co., Ltd.).

  The support layer may be a single layer or a multilayer structure composed of two or more layers. Moreover, you may give processes, such as embossing or a corona treatment, to the single side | surface.

(Cushion layer)
The cushion layer according to the present invention needs to have a breaking elongation of 1000% or less and a tensile elastic modulus of 10 MPa or less. When the cushion layer has such characteristics, the photosensitive film of the present invention has excellent followability with respect to the uneven portions present on the substrate surface when placed on the substrate surface. The adhesive film and the substrate are sufficiently adhered, and no gap is generated between them.

  Furthermore, in the process accompanied by cutting such as the slitting process of the photosensitive film and / or the crimping process to the substrate by having a breaking elongation of 1000% or less and having a tensile elastic modulus of 10 MPa or less, The cut surface of the photosensitive film is in a good state, and there is no wrinkle portion on the cut surface, and no resin piece derived from cutting is generated.

  Since the photosensitive film of this invention has such a characteristic, it can respond to the densification of the wiring on a printed wiring board, and can provide a high-resolution printed wiring board.

  The resin contained in the cushion layer preferably has a breaking elongation of 500% or less, and particularly preferably has a breaking elongation of 300% or less in order to make the cut surface smoother.

In the present invention, the elongation at break of the cushion layer is measured and calculated as follows using a testing machine such as a rheometer. That is, first, the resin itself contained and used in the cushion layer is dissolved in an organic solvent such as toluene. Subsequently, an appropriate amount of the solution is put in a metal petri dish or the like and dried at 60 to 90 ° C. for 30 minutes to obtain a solid material. The solid material is molded into a test piece having a width of 5 mm and a thickness of 250 μm. Next, the gripping tool is attached to the test piece so that the distance between the gripping tools is 5 mm. Then, under the conditions of a temperature of 23 ° C. and a relative humidity of 60%, the test piece is pulled using the test machine having the above-described gripping tool until the test piece breaks. The distance between grips when the test piece broke was A (mm), and the elongation at break E _f (%) was expressed by the following formula (1);
E _f = (A-5) / 5 × 100 (1)
Is calculated by

  Further, the resin contained in the cushion layer described above preferably has a tensile elastic modulus of 5 MPa in order to further improve the followability to uneven portions present on the substrate surface, and has a tensile elastic modulus of 3 MPa. It is more preferable.

In the present invention, the tensile elastic modulus is measured and calculated as follows using a testing machine such as a rheometer. First, a test piece is prepared in the same manner as in the case of the elongation at break described above. Next, the test piece is pulled under the same conditions as in the case of the elongation at break described above. Then, tensile stress of the test piece - creating strain curve, using the linear part of its initial tensile modulus E _m (MPa) satisfies the following formula (2);
E _m = Δσ / Δε (2)
Is calculated by Here, Δσ represents the difference in stress due to the original average cross-sectional area between two points on the straight line, and Δε represents the difference in strain between the two points.

  If the resin contained in the cushion layer mentioned above has the said characteristic, the kind will be used without being specifically limited. Among these, the resin is preferably a rubber such as polybutadiene, polyisoprene, polyneoprene, styrene-butadiene copolymer, or a copolymer having ethylene as a copolymerization component. Further, it is particularly preferable to use ethylene-vinyl acetate copolymer (EVA), ethylene-ethyl acrylate copolymer (EEA), or ethylene-methyl methacrylate copolymer (EMMA) as the resin.

  The copolymer containing ethylene as a copolymerization component preferably has an ethylene unit content of 50 to 90% by mass, more preferably 50 to 80% by mass, and 60 to 80% by mass. Particularly preferred. When the ethylene unit content is less than 50% by mass, the adhesion of the cushion layer to the photosensitive layer tends to be too high and peeling tends to be difficult. Further, when the ethylene unit content exceeds 90% by mass, the adhesion between the cushion layer and the photosensitive layer becomes low and easily peels off, making it difficult to produce a photosensitive film provided with the cushion layer. There is a tendency.

  The cushion layer preferably has a thickness of 1 to 100 μm, more preferably 2 to 50 μm, and particularly preferably 5 to 40 μm. When the cushion layer has a thickness of less than 1 μm, the followability of the photosensitive film including the cushion layer to the concavo-convex portion of the substrate surface tends to decrease. Moreover, when the thickness exceeds 100 μm, the manufacturing cost tends to be too high.

  Moreover, in the range which does not inhibit the objective of this invention, this cushion layer can also contain the additive used for a photosensitive film as needed other than the resin mentioned above. For example, (A) component, (B) component, or (C) component which will be described later can also be contained, thereby sufficiently transferring (B) component or (C) component from the photosensitive layer to the cushion layer. Can be suppressed.

(Photosensitive layer)
The photosensitive layer according to the present invention can be used for a photosensitive film, and can be photocured by irradiating actinic rays such as ultraviolet rays, electron beams, ion beams, X-rays or excimer lasers to form a photocured portion. If it is, it will be used without being particularly limited. Here, as an active light source, a known light source, for example, a carbon arc lamp, a mercury vapor arc lamp, a high-pressure mercury lamp, a xenon lamp, a photographic flood bulb, a solar lamp, or the like, effectively radiates ultraviolet rays or visible light. Things are used. It is also used for laser direct drawing exposure.

  As the photosensitive layer according to the present invention, it is preferable to use a photosensitive layer containing a monomer that forms a resin by irradiation with actinic rays as described above. Among these, from the viewpoint of versatility and shortening the manufacturing process time, it is preferable to use a material that is cured by forming a resin with ultraviolet rays.

  What cures by forming a resin with ultraviolet rays is (A) a binder polymer, (B) a photopolymerizable compound having at least one polymerizable ethylenically unsaturated bond in the molecule, and (C) initiation of photopolymerization. More preferably, it is a photosensitive resin composition containing an agent. A photosensitive layer containing such a photosensitive resin composition can be used for a photosensitive film together with the cushion layer described above, thereby providing excellent photosensitivity, developability, chemical resistance, flexibility, mechanical strength, and the like. It can be applied to the film.

  Examples of the binder polymer as the component (A) include polyester resins, acrylic resins, styrene resins, epoxy resins, amide resins, amide epoxy resins, alkyd resins, phenol resins, and urethane resins. It is done. These binder polymers can be used alone or in combination of two or more.

  The binder polymer is preferably obtained by polymerizing a monomer having an ethylenically unsaturated double bond (such as radical polymerization). Examples of the monomer having an ethylenically unsaturated double bond include, for example, styrene; α-position or aromatic ring such as vinyltoluene, α-methylstyrene, p-methylstyrene, p-methoxystyrene, and p-chlorostyrene. Polymerizable styrene derivatives having substituents in acrylamide; acrylamides such as diacetone acrylamide; acrylonitrile; esters of vinyl alcohol such as vinyl-n-butyl ether; alkyl (meth) acrylate, tetrahydrofurfuryl ester of (meth) acrylic acid , (Meth) acrylic acid dimethylaminoethyl ester, (meth) acrylic acid glycidyl ester, 2,2,2-trifluoroethyl (meth) acrylate, (meth) acrylic acid, α-bromo (meth) acrylic acid, β- Furyl (meth) acrylic acid, β-styryl (Meth) acrylic acid monomers such as ru (meth) acrylic acid; maleic acid monomers such as maleic acid, maleic anhydride, monomethyl maleate, etc. In addition to these, fumaric acid, Examples thereof include cinnamic acid, α-cyanocinnamic acid, itaconic acid, crotonic acid, and propiolic acid.

で示される化合物や、一般式（３）で示される化合物のアルキル基に水酸基、エポキシ基、ハロゲン基等が置換した化合物などが挙げられる。なお、式中、Ｒ¹は水素原子又はメチル基を示し、Ｒ²は炭素数１〜１２のアルキル基を示す。一般式（３）中のＲ²で示される炭素数１〜１２のアルキル基としては、例えば、メチル基、エチル基、プロピル基、ブチル基、ペンチル基、ヘキシル基、ヘプチル基、オクチル基、ノニル基、デシル基、ウンデシル基、ドデシル基及びこれらの構造異性体が挙げられる。 As said (meth) acrylic-acid alkylester, the following general formula (3);

Or a compound in which a hydroxyl group, an epoxy group, a halogen group or the like is substituted on the alkyl group of the compound represented by the general formula (3). In the formula, R ¹ represents a hydrogen atom or a methyl group, and R ² represents an alkyl group having 1 to 12 carbon atoms. Examples of the alkyl group having 1 to 12 carbon atoms represented by R ² in the general formula (3) 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, and a nonyl group. Group, decyl group, undecyl group, dodecyl group and structural isomers thereof.

  Examples of the monomer represented by the general formula (3) 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, and the like. These monomers can be used alone or in combination of two or more.

  The binder polymer is preferably composed of one or more kinds of polymers having a carboxyl group from the viewpoint of developability when alkali development is performed using an alkaline solution.

  From the viewpoint of flexibility, the polymer having a carboxyl group is referred to as (meth) acrylic acid, (meth) acrylic acid alkyl ester, and a monomer copolymerizable therewith (hereinafter referred to as “copolymerization monomer”). And a copolymer thereof. As the comonomer, styrene and / or a styrene derivative is preferable to further improve flexibility, and styrene is more preferable.

  In the copolymer of (meth) acrylic acid, (meth) acrylic acid alkyl ester and styrene and / or styrene derivatives, the total mass ratio of styrene and / or styrene derivatives is the total mass of the polymerizable monomer. As a reference, it is preferably 0.1 to 60% by mass, more preferably 1 to 40% by mass, and particularly preferably 1.5 to 30% by mass. If the total content of styrene and / or styrene derivatives is less than 0.1% by mass, the adhesion tends to be insufficient, and if it exceeds 60% by mass, the peel piece tends to be large and the peel time tends to be long. There is.

  Moreover, it is preferable that the acid value of (A) component is 50-500 mgKOH / g, and it is more preferable that it is 100-300 mgKOH / g. When the acid value is less than 50 mgKOH / g, the development time tends to be long, and when it exceeds 500 mgKOH / g, the developer resistance of the photocured photosensitive resin composition tends to be lowered.

  The weight average molecular weight (Mw) and number average molecular weight (Mn) of the component (A) can be measured by gel permeation chromatography (GPC) (converted by a calibration curve using standard polystyrene). According to this measuring method, the Mw of the binder polymer is preferably 5,000 to 300,000, and more preferably 10,000 to 150,000. When the Mw is less than 5,000, the developer resistance tends to decrease, and when it exceeds 300,000, the development time tends to be long.

  Further, the degree of dispersion (Mw / Mn) of the binder polymer is preferably 1.0 to 3.0, and more preferably 1.0 to 2.5. When the degree of dispersion exceeds 3.0, the adhesiveness and resolution tend to decrease.

  In addition, the binder polymer in the present invention includes 2 such as (phthalic anhydride), isophthalic acid, terephthalic acid, tetrahydrophthalic anhydride, (anhydrous) maleic acid, fumaric acid, adipic acid trimellitic anhydride, pyromellitic anhydride, etc. Carboxylic acid having higher valency and dihydric or higher alcohol such as ethylene glycol, propylene glycol, 1,3-butanediol, diethylene glycol, dipropylene glycol, triethylene glycol, neopentyl glycol, hydrogenated bisphenol A, glycerin, trimethylolpropane, etc. A polyester resin obtained by an esterification reaction with can also be used. Examples of the epoxy resin include bisphenol epoxy resin and novolac epoxy resin, and those added with a monovalent carboxylic acid such as acetic acid, oxalic acid and (meth) acrylic acid.

  The binder polymer contained in the component (A) described above can be used alone or in combination of two or more. As a binder polymer in the case of using two or more types in combination, for example, two or more types of binder polymers comprising different copolymerization components, two or more types of binder polymers having different weight average molecular weights, and two or more types of binder polymers having different degrees of dispersion are used. Examples thereof include a binder polymer.

  Furthermore, these binder polymers may have a photosensitive group in the molecule as necessary.

  Examples of the photopolymerizable compound (hereinafter simply referred to as “photopolymerizable compound”) having at least one polymerizable ethylenically unsaturated bond in the molecule as the component (B) include bisphenol A (meth). Acrylate compound; Compound obtained by reacting α, β-unsaturated carboxylic acid with polyhydric alcohol; Compound obtained by reacting glycidyl group-containing compound with α, β-unsaturated carboxylic acid; Urethane bond in the molecule Examples thereof include urethane monomers such as (meth) acrylate compounds, nonylphenoxypolyoxyethylene acrylate; γ-chloro-β-hydroxypropyl-β ′-(meth) acryloyloxyethyl-o-phthalate, β -Hydroxyalkyl-β '-(meth) acryloyloxyalkyl-o-phthalates and other phthalates System compound; (meth) acrylic acid alkyl ester can be exemplified. These may be used alone or in combination of two or more.

で表される化合物が好ましく挙げられる。 As a bisphenol A type (meth) acrylate compound, for example, the following general formula (4);

A compound represented by the formula is preferred.

In the general formula (4), R ¹¹ and R ¹² each independently represent a hydrogen atom or a methyl group, preferably a methyl group. In the general formula (4), R ¹³ and R ¹⁴ each independently represent an alkylene group having 2 to 6 carbon atoms, and are preferably an ethylene group or an isopropylene group from the viewpoints of resolution and plating resistance.

  In the general formula (4), p and q are positive integers selected so that p + q = 4 to 40, and the value of p + q is preferably 6 to 34, more preferably 8 to 30. It is particularly preferably 8 to 28, very preferably 8 to 20, very preferably 8 to 16, and most preferably 8 to 12. When the value of p + q is less than 4, the compatibility with the component (A) decreases, and when the photosensitive film is pressure-bonded to the substrate, it tends to be peeled off. When the value of p + q exceeds 40, hydrophilicity increases. However, the resist image is easily 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, and it tends to be difficult to achieve high density and high resolution of the printed wiring board.

  The aromatic ring in the general formula (4) may have a substituent, and examples of the substituent include a halogen atom, an alkyl group having 1 to 20 carbon atoms, and a cyclohexane having 3 to 10 carbon atoms. Alkyl group, aryl group having 6 to 18 carbon atoms, phenacyl group, amino group, alkylamino group having 1 to 10 carbon atoms, dialkylamino group having 2 to 20 carbon atoms, nitro group, cyano group, carbonyl group, mercapto group, A C1-C10 alkyl mercapto group, an allyl group, a hydroxyl group, a C1-C20 hydroxyalkyl group, a carboxyl group, a C1-C10 carboxyalkyl group, and a C1-C10 alkyl group. 10 acyl groups, C1-C20 alkoxy groups, C1-C20 alkoxycarbonyl groups, C2-C10 alkylcarbonyl groups, C2-C10 alkyls Alkenyl group, N- alkylcarbamoyl group or a group containing a heterocyclic ring having 2 to 10 carbon atoms, or an aryl group substituted by these substituents. 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 (4) 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), 2,2-bis (4-((meth) acryloxyundecaethoxy) phenyl), 2,2- Bis (4-((meth) acryloxydodecaethoxy) phenyl), 2,2-bis (4-((meth) acryloxytridecaethoxy) phenyl), 2,2-bis (4-((meth) acrylic) Loxytetradecaethoxy) phenyl), 2,2-bis (4-((meth) acryloxypentadecaethoxy) phenyl), 2,2-bis (4-((meth) acryloxyhexadecaethoxy) phenyl), etc. 2,2-bis (4- (methacryloxypentaethoxy) phenyl) propane is commercially available as BPE-500 (product name, manufactured by Shin-Nakamura Chemical Co., Ltd.) An ability, 2,2-bis (4- (methacryloxy pentadecanoyl) phenyl) is, BPE-1300 (trade name, Chemical Industry Co., Ltd. Shin-Nakamura) is commercially available as. These can be used alone or in combination of two or more.

  Examples of 2,2-bis (4-((meth) acryloxypolypropoxy) phenyl) propane include 2,2-bis (4-((meth) acryloxydipropoxy) phenyl) propane, 2,2- Bis (4-((meth) acryloxytripropoxy) phenyl) propane, 2,2-bis (4-((meth) acryloxytetrapropoxy) phenyl) propane, 2,2-bis (4-((meth)) Acryloxypentapropoxy) phenyl) propane, 2,2-bis (4-((meth) acryloxyhexapropoxy) phenyl) propane, 2,2-bis (4-((meth) acryloxyheptapropoxy) phenyl) propane 2,2-bis (4-((meth) acryloxyoctapropoxy) phenyl) propane, 2,2-bis (4-((meth) acrylic) Xinonapropoxy) phenyl) propane, 2,2-bis (4-((meth) acryloxydecapropoxy) phenyl), 2,2-bis (4-((meth) acryloxyundecapropoxy) phenyl), 2 , 2-bis (4-((meth) acryloxydodecapropoxy) phenyl), 2,2-bis (4-((meth) acryloxytridecapropoxy) phenyl), 2,2-bis (4-(( (Meth) acryloxytetradecapropoxy) phenyl), 2,2-bis (4-((meth) acryloxypentadecapropoxy) phenyl), 2,2-bis (4-((meth) acryloxyhexadecapropoxy) Phenyl) and the like. 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 can be used alone or in combination of two or more.

  Examples of the compound obtained by reacting a polyhydric alcohol with an α, β-unsaturated carboxylic acid include, for example, polyethylene glycol di (meth) acrylate having 2 to 14 ethylene groups and 2 to 14 propylene groups. Polypropylene glycol di (meth) acrylate, polyethylene polypropylene glycol di (meth) acrylate having 2 to 14 ethylene groups and 2 to 14 propylene groups, trimethylolpropane di (meth) acrylate, tri Methylolpropane tri (meth) acrylate, EO-modified trimethylolpropane tri (meth) acrylate, PO-modified trimethylolpropane tri (meth) acrylate, EO / PO-modified trimethylolpropane tri (meth) acrylate, tetramethylolmethanetri (meth) A Examples thereof include acrylate, tetramethylolmethane tetra (meth) acrylate, dipentaerythritol penta (meth) acrylate, and dipentaerythritol hexa (meth) acrylate. These may be used alone or in combination of two or more.

“EO” refers to “ethylene oxide”, and “PO” refers to “propylene oxide”. “EO modified” means having a block structure of ethylene oxide units (—CH ₂ —CH ₂ —O—), and “PO modified” means propylene oxide units (—CH ₂ —CH ₂ —CH _2). -O-) having a block structure.

  Examples of the compound obtained by reacting a glycidyl group-containing compound with an α, β-unsaturated carboxylic acid include trimethylolpropane triglycidyl ether tri (meth) acrylate, 2,2-bis (4- (meth) acryloxy- 2-hydroxy-propyloxy) phenyl and the like are fisted.

  Examples of the α, β-unsaturated carboxylic acid include (meth) acrylic acid.

  Examples of urethane monomers include (meth) acrylic monomers having an OH group at the β-position and diisocyanate compounds such as isophorone diisocyanate, 2,6-toluene diisocyanate, 2,4-toluene diisocyanate, and 1,6-hexamethylene diisocyanate. Additional reaction products, tris ((meth) acryloxytetraethylene glycol isocyanate) hexamethylene isocyanurate, EO-modified urethane di (meth) acrylate, EO or PO-modified urethane di (meth) acrylate, and the like can be mentioned.

  Furthermore, examples of the (meth) acrylic acid alkyl ester include (meth) acrylic acid methyl ester, (meth) acrylic acid ethyl ester, (meth) acrylic acid butyl ester, (meth) acrylic acid 2-ethylhexyl ester, and the like. It is done.

  These (B) components are used individually by 1 type or in combination of 2 or more types.

  Examples of the photopolymerization initiator (C) include benzophenone; N, N′-tetraalkyl-4,4′-diaminobenzophenone; 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl). Aromatic ketones such as butanone-1,2-methyl-1- [4- (methylthio) phenyl] -2-morpholino-propanone-1; quinones such as alkylanthraquinones; benzoin ether compounds such as benzoin alkyl ethers; benzoin Benzoin compounds such as alkylbenzoin; benzyl derivatives such as benzyldimethyl ketal; 2,4,5-triarylimidazole dimer; 9-phenylacridine, 1,7-bis (9,9′-acridinyl) heptane, etc. Acridine derivatives; N-phenylglycine, N-phenylglycine derivatives Body, and coumarin compounds. These can be used alone or in combination of two or more.

  Among these, 2,4,5-triarylimidazole dimer is more preferable from the viewpoint of adhesion and photosensitivity. The 2,4,5-triarylimidazole dimer may give a symmetric compound in which the aryl group substituent is the same, or the aryl group substituent is non-identical and an asymmetric compound. May be given.

  More preferable triarylimidazole dimers include, for example, 2,2′-bis (o-chlorophenyl) -4,5,4 ′, 5′-tetraphenyl-1,2′-biimidazole, 2- (o -Chlorophenyl) -4,5-diphenylimidazole dimer, 2,2'-bis (o-chlorophenyl) -4,4 ', 5,5'-tetra (p-chlorophenyl) imidazole dimer, 2- ( o-chlorophenyl) -4,5-di (m-methoxyphenyl) imidazole dimer, 2,2′-bis (o-chlorophenyl) -4,4 ′, 5,5′-tetra (p-fluorophenyl) Imidazole dimer, 2,2′-bis (o-bromophenyl) -4,4 ′, 5,5′-tetra (p-chloro-p-methoxyphenyl) imidazole dimer, 2,2′-bis (O-black Phenyl) -4,4 ′, 5,5′-tetra (o, p-dichlorophenyl) imidazole dimer, 2,2′-bis (o-chlorophenyl) -4,4 ′, 5,5′-tetra ( o, p-dibromophenyl) imidazole dimer, 2,2′-bis (o-chlorophenyl) -4,4 ′, 5,5′-tetra (p-chloronaphthyl) imidazole dimer, 2,2 ′ -Bis (m, p-dichlorophenyl) -4,4 ', 5,5'-tetraphenylimidazole dimer, 2,2'-bis (o, p-dichlorophenyl) -4,4', 5,5 ' -Tetraphenylimidazole dimer, 2,2'-bis (o, p-dichlorophenyl) -4,4 ', 5,5'-tetra (o, p-dichlorophenyl) imidazole dimer, 2- (o- Fluorophenyl) -4,5-dipheni Imidazole dimer, 2- (o-methoxyphenyl) -4,5-diphenylimidazole dimer, 2- (p-methoxyphenyl) -4,5-diphenylimidazole dimer, 2,4-di (p -Methoxyphenyl) -5-phenylimidazole dimer, 2- (2,4-dimethoxyphenyl) -4,5-diphenylimidazole dimer, 2- (p-methylmercaptophenyl) -4,5-diphenylimidazole Dimer, 2,2′-bis (p-bromophenyl) -4,4 ′, 5,5′-tetraphenylimidazole dimer, 2,2′-bis (o-bromophenyl) -4,4 ', 5,5'-tetra (o, p-dichlorophenyl) imidazole dimer, 2,2'-bis (o-bromophenyl) -4,4', 5,5'-tetra (p-iodophenyl) B Midazole dimer, 2,2′-bis (m-bromophenyl) -4,4 ′, 5,5′-tetraphenylimidazole dimer, 2,2′-bis (m, p-dibromophenyl)- 4,4 ′, 5,5′-tetraphenylimidazole dimer and the like. These can be used alone or in combination of two or more.

  The content of the component (A) in the photosensitive layer is preferably 30 to 80 parts by mass with respect to 100 parts by mass of the total amount of the components (A) and (B), and is 45 to 70 parts by mass. It is more preferable. If the amount is less than 30 parts by mass, the resulting photocured product tends to be brittle, and if it exceeds 80 parts by mass, the resolution and photosensitivity tend to be insufficient.

  The content of the component (B) is preferably 20 to 60 parts by mass and more preferably 30 to 55 parts by mass with respect to 100 parts by mass as the total of the components (A) and (B). . If the blending amount is less than 20 parts by mass, the resolution and photosensitivity tend to be insufficient, and if it exceeds 60 parts by mass, the photocured product tends to be brittle.

  The content of the component (C) is preferably 0.1 to 20 parts by mass, and 0.2 to 10 parts by mass with respect to 100 parts by mass as the total of the components (A) and (B). It is more preferable. 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 There is a tendency that the photocuring of is insufficient.

  In addition, the photosensitive resin composition may include a dye such as malachite green or diamond green, a photochromic agent such as tribromophenyl sulfone or leuco crystal violet, a thermochromic inhibitor, p-toluenesulfonamide, or the like, if necessary. Plasticizer, pigment, filler, antifoaming agent, flame retardant, stabilizer, adhesion-imparting agent, leveling agent, peeling accelerator, antioxidant, fragrance, imaging agent, thermal crosslinking agent, etc. (B) About 0.01-20 mass parts can be contained respectively with respect to 100 mass parts of total amounts of a component. These can be used alone or in combination of two or more.

  Furthermore, the photosensitive resin composition may be mixed with a solvent such as methanol, ethanol, acetone, methyl ethyl ketone, methyl cellosolve, ethyl cellosolve, toluene, N, N-dimethylformamide, propylene glycol monomethyl ether, or a mixed solvent thereof as necessary. It melt | dissolves and it can apply | coat as a solution of about 30-60 mass% solid content.

  The photosensitive layer preferably has a thickness of 0.1 to 50 [mu] m, more preferably 0.1 to 25 [mu] m, and more preferably 1 to 15 [mu] m from the viewpoint of increasing the density and resolution of the printed wiring board. More preferably, it has a thickness of 1 to 8 μm, and particularly preferably has a thickness of 2 to 7 μm.

  In the case where this photosensitive layer contains 2,2-bis (4-((meth) acryloxypolyalkoxy) phenyl) propane as the component (B), from the viewpoint of increasing the density and resolution of the printed wiring board. More preferably, it has a thickness of 0.1 to 15 μm, more preferably 2 to 15 μm, and particularly preferably 1 to 7 μm.

  In the case where a photosensitive layer containing a monomer that forms a resin by ultraviolet irradiation and is cured is used, the transmittance of the photosensitive layer with respect to ultraviolet rays having a wavelength of 365 nm is preferably 5 to 75%. More preferably, it is -60%, and it is especially preferable that it is 10-40%. If the transmittance is less than 5%, the adhesiveness of the photosensitive film to the substrate tends to be inferior, and if it exceeds 75%, the resolution tends to be inferior. The transmittance can be measured with a UV spectrometer, and examples of the UV spectrometer include a 228A type W beam spectrophotometer manufactured by Hitachi, Ltd.

  In the photosensitive film comprising the support layer of the present invention, a cushion layer formed on the support layer, and a photosensitive layer formed on the cushion layer, a protective film is further formed on the photosensitive layer. be able to.

  Since the protective film is peeled off from the photosensitive film before the photosensitive film is pressure-bonded to the substrate, the protective film has flexibility and can be releasably adhered to the photosensitive layer, and the photosensitive layer is dried. Any material can be used without particular limitation as long as it is not damaged at any temperature (usually about 100 ° C.).

  Specifically, for example, polyester such as paper, release paper, polyethylene terephthalate, polyolefin such as polymethylpentene, polypropylene and polyethylene, halogen-containing vinyl polymer such as polyvinyl fluoride and polyvinyl chloride, polyamide such as nylon, cellophane, etc. Examples thereof include films such as cellulose and polystyrene.

  The protective film may be transparent or non-transparent, and may have been subjected to a release treatment. Examples of the available cover film include product name E-200H manufactured by Oji Paper Co., Ltd., and product name NF-13 manufactured by Tamapoli Co., Ltd.

  This protective film is usually stored in the form of a roll. However, in consideration of this point, the protective film preferably has a thickness of 10 to 30 μm, more preferably 10 to 25 μm, and a thickness of 10 to 20 μm. Particularly preferred.

  The interlayer adhesive force between the cushion layer and the photosensitive layer described above is preferably smaller than the interlayer adhesive force between the support layer and the cushion layer. If the support layer is opaque and the cushion layer is transparent during exposure after the photosensitive film is pressure-bonded to the substrate, it is necessary to peel only the support layer, If it exists, it exists in the tendency for it to become easy to peel only a support layer.

  Further, when the photosensitive film also includes the protective film as described above, it is preferable that the interlayer adhesive force between the protective film and the photosensitive layer is smaller than the interlayer adhesive force between the cushion layer and the photosensitive layer. . This tends to make it easy to peel only the protective film from the sensitive film before the photosensitive film is pressure-bonded to the substrate.

  In addition, these interlayer adhesive strengths use a device such as a rheometer, for example, under the conditions of a temperature of 23 ° C. and a relative humidity of 60%, the 180 ° C. peel strength (slightly peels one edge of the layer to be peeled, It is obtained indirectly by measuring the force required per unit length when the edge is folded back at 180 ° C .; hereinafter referred to as “peel strength”.

  As the peel strength, the ratio of the peel strength between the support layer and the cushion layer to the peel strength between the cushion layer and the photosensitive layer, or the cushion layer and the photosensitive layer with respect to the peel strength between the protective film and the photosensitive layer, The peel strength ratio is more preferably 1.05 or more, further preferably 1.5 or more, and particularly preferably 2.0 or more. When the ratio of these peel strengths is less than 1.05, peeling tends to occur between layers different from the desired layers.

  The photosensitive film may further have an intermediate layer such as an adhesive layer, a light absorption layer, and a gas barrier layer, a protective layer, and the like.

  Next, a method for producing a photosensitive film will be described. The production method of the photosensitive film is not particularly limited as long as a photosensitive film having the above-described configuration can be produced. Therefore, for example, it may be produced by forming a cushion layer on the support layer and then forming a photosensitive layer on the cushion layer. Or you may produce by forming a photosensitive layer on a cushion layer, forming a cushion layer on a support layer.

  When a protective film is provided, the cushion layer is formed on the support layer and the photosensitive layer is formed on the protective film by bonding the cushion layer and the photosensitive layer so that they face each other. May be. Alternatively, it may be prepared by forming a photosensitive layer on a protective film, then forming a cushion layer on the photosensitive layer, and forming a support layer on the cushion layer. Furthermore, it may be produced by forming a cushion layer on the photosensitive layer while forming a photosensitive layer on the protective film, and then forming a support layer on the cushion layer.

  In addition, the photosensitive layer is formed on the cushion layer by applying the above-described photosensitive resin composition to the cushion layer. At this time, methanol, ethanol, acetone, methyl ethyl ketone, methyl cellosolve are used as necessary. And dissolved in a solvent such as ethyl cellosolve, toluene, N, N-dimethylformamide, propylene glycol monomethyl ether, or a mixed solvent thereof, and applied as a solution having a solid content of about 30 to 70% by mass.

  The photosensitive film thus obtained can be stored in the form of a sheet or a roll wound around a core.

  Since the photosensitive film of the present invention described above can be produced using conventional equipment and materials, the manufacturing cost of the printed wiring board is not improved, and the resolution and pattern accuracy of the printed wiring are improved. Can be made. Therefore, it is very useful for increasing the density and resolution of a printed wiring board.

  Moreover, since this photosensitive film has flexibility, when the photosensitive film is pressure-bonded to the substrate, it can be satisfactorily adhered even when the substrate surface is rich in irregularities. In particular, even if the cushion layer and the photosensitive layer provided in the photosensitive film are thinner than conventional ones, excellent followability of the photosensitive film to the concavo-convex portions on the substrate surface can be maintained. And since it can crimp by using the conventional apparatus, the increase in production cost by the change of an apparatus or the change of a process, etc. will not arise.

  Next, the manufacturing method of the printed wiring board of this invention is demonstrated. The manufacturing method includes a laminating step of laminating a photosensitive film as described above on a circuit forming substrate in the order of a photosensitive layer, a cushion layer, and a supporting layer; Irradiating a predetermined portion of the photosensitive layer through the layer to form a photocured portion on the photosensitive layer, a peeling step for removing the support layer and the cushion layer from the photosensitive film, and a portion other than the photocured portion And a developing step for removing the photosensitive layer.

  Moreover, you may perform a peeling process before an exposure process among the said processes. In this case, the exposure process is performed by directly irradiating a predetermined portion of the photosensitive layer with actinic rays to form a photocured portion on the photosensitive layer. Furthermore, a peeling process may perform only the step which peels a support layer before an exposure process, and the step which peels a cushion layer may be performed after an exposure process. In this case, the exposure step is performed by irradiating a predetermined portion of the photosensitive layer with actinic rays only through the cushion layer to form a photocured portion in the photosensitive layer.

  In the laminating step, as a method of laminating the photosensitive layer provided in the photosensitive film on the substrate, when a protective film is present on the photosensitive layer, the protective film is gradually peeled from the photosensitive layer, and A method of laminating by gradually pressing the surface of the photosensitive layer that is gradually exposed to about 70 to 130 ° C. while being pressure-bonded to the substrate at a pressure of about 0.1 to 1 MPa is mentioned. Lamination is performed under reduced pressure. Is also possible. In addition, although the surface on which a board | substrate is laminated | stacked is a metal surface normally, it does not restrict | limit in particular. In addition, in order to further improve the stackability, the substrate may be preheated.

  The exposure step is performed by irradiating the photosensitive layer, which has been laminated in the laminating step, with an actinic ray in an image form through a negative or positive mask pattern to form a photocured portion on the photosensitive layer. At this time, when the cushion layer or the support layer provided on the photosensitive layer is transparent, actinic rays can be irradiated in a state in which they are provided on the photosensitive layer. When the support layer or cushion layer is opaque, the photosensitive layer is irradiated with actinic rays after peeling off those layers as necessary.

  In the development process, if the support layer or the cushion layer remains on the photosensitive layer, after peeling and removing them, wet development with a developer such as an alkaline aqueous solution, an aqueous developer, an organic solvent, or dry development is performed. This is performed by removing an unexposed portion (photocured portion), whereby a resist pattern can be formed.

  As the developer, an alkaline aqueous solution is preferably used from the viewpoint of safety, stability, operability, and the like. Examples of the base of the alkaline aqueous solution include alkali hydroxides such as lithium, sodium or potassium hydroxide, alkali carbonates such as lithium, sodium, potassium or ammonium carbonate or bicarbonate, potassium phosphate, sodium phosphate And alkali metal pyrophosphates such as sodium pyrophosphate and potassium pyrophosphate. Moreover, as alkaline aqueous solution used for image development, 0.1-5 mass% dilute solution of sodium carbonate, 0.1-5 mass% dilute solution of potassium carbonate, 0.1-5 mass% dilute solution of sodium hydroxide, A dilute solution of 0.1 to 5% by mass sodium tetraborate is preferred. Moreover, it is preferable to make pH of the alkaline aqueous solution used for image development into the range of 9-11, and the temperature is adjusted according to the developability of the photosensitive resin composition layer. In the alkaline aqueous solution, a surfactant, an antifoaming agent, a small amount of an organic solvent for accelerating development, and the like may be mixed.

  The aqueous developer comprises water or an alkaline aqueous solution and one or more organic solvents. Examples of the alkaline aqueous solution include, in addition to the above substances, borax, sodium metasilicate, tetramethylammonium hydroxide, ethanolamine, ethylenediamine, diethylenetriamine, 2-amino-2-hydroxymethyl-1, 3-propanediol, 1 , 3-diaminopropanol-2, morpholine and the like. The pH of the developer is preferably as low as possible within a range where the resist can be sufficiently developed, preferably pH 8-12, more preferably pH 9-10.

  Examples of the organic solvent include triacetone alcohol, acetone, ethyl acetate, alkoxyethanol having an alkoxy group having 1 to 4 carbon atoms, ethyl alcohol, isopropyl alcohol, butyl alcohol, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether. Etc. These are used singly or in combination of two or more. The concentration of the organic solvent is usually preferably 2 to 90% by mass, and the temperature can be adjusted according to the developability. Further, a small amount of a surfactant, an antifoaming agent or the like can be mixed in the aqueous developer. Examples of the organic solvent-based developer used alone include 1,1,1-trichloroethane, N-methylpyrrolidone, N, N-dimethylformamide, cyclohexanone, methyl isobutyl ketone, and γ-butyrolactone. These organic solvents preferably add water in the range of 1 to 20% by mass in order to prevent ignition. Moreover, you may use together 2 or more types of image development methods as needed.

  Development methods include a dip method, a battle method, a spray method, brushing, and slapping, and the high pressure spray method is most suitable for improving the resolution.

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.

  In the method for producing a printed wiring board, usually, a resist pattern is formed on a substrate as described above, and then the substrate is etched or plated. Here, the etching or plating of the substrate is performed by etching or plating the surface of the 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. Of these, ferric chloride solution is preferably used because it tends to have a good etch factor.

  Examples of 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 watt bath (nickel sulfate-nickel chloride) plating, nickel sulfamate plating, and hard gold plating. And gold plating such as soft 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 mass sodium hydroxide aqueous solution, a 1 to 10% by mass 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 the present invention, by using the photosensitive film as described above, even if a resist pattern is formed on these printed wiring boards, the developability and releasability of the resist film affect the yield of printed wiring board manufacture. It will not drop as much.

  EXAMPLES Hereinafter, although an Example demonstrates this invention further in detail, this invention is not limited to these Examples.

  First, the component shown in Table 1 was mix | blended and the solution of the photosensitive resin composition was obtained. In addition, 2,2'-bis ((4-methacryloxypentaethoxy) phenyl) propane, which is one of the components (B), was commercially available (manufactured by Shin-Nakamura Chemical Co., Ltd.).

  Next, the components shown in Table 2 were blended to obtain cushion layer materials (1) to (4).

(Example 1)
First, a 16 μm thick polyethylene terephthalate film (G2-16, manufactured by Teijin Ltd., trade name) was prepared as a base film. On top of that, the cushion layer material (1) was uniformly applied so that the thickness after drying was 20 μm, and dried for 10 minutes with a hot air convection dryer at 115 ° C. to form a cushion layer. Next, the photosensitive resin composition solution described above is uniformly applied onto the cushion layer so that the thickness after drying becomes 6 μm, and dried for 10 minutes in a hot air convection dryer at 100 ° C. A layer was formed. Subsequently, a biaxially stretched polypropylene film (E-200H, trade name, manufactured by Oji Paper Co., Ltd.) having a thickness of 20 μm as a protective film was brought into close contact with the photosensitive layer to obtain a photosensitive film of Example 1. The obtained photosensitive film was wound around a branch tube so that the base film was on the outside.

(Example 2, Comparative Examples 1 and 2)
The photosensitive films of Example 2 and Comparative Examples 1 and 2 were obtained in the same manner as in Example 1 except that the cushion layer materials (2) to (4) were used instead of the cushion layer material (1). It was.

  Table 3 shows the measurement results of the tensile elastic modulus and elongation at break of the cushion layer provided in the obtained photosensitive film.

[Evaluation of cutting ability]
First, the wound photosensitive film was loosened somewhat. Next, using the cutter blade, the photosensitive film is separated into two parts by cutting the middle part in the width direction of the unwound portion of the photosensitive film in the longitudinal direction, and separating the photosensitive film into two parts. Only the protective film was wound around another branch pipe at a speed of 10 m / min. After completion of rewinding, the surface cut using a cutter blade was visually observed to confirm whether or not a crest portion was present on the cut surface of the cushion layer. The results are shown in Table 3.

[Evaluation of unevenness followability]
A polishing machine with a brush equivalent to # 600 on the copper surface of a glass epoxy board (MCL-E67-35S, manufactured by Hitachi Chemical Co., Ltd., product name) laminated with 35 μm thick copper foil on one side (Sankei Co., Ltd.) And then washed with water and dried by air flow to obtain a copper clad laminate.

  Next, the obtained copper-clad laminate was heated to 80 ° C., and then a negative photosensitive film (Hitachi Chemical Industries Co., Ltd.) was used on the substrate using a high-temperature laminator (HLM-3000, manufactured by Hitachi Chemical Co., Ltd.). The photosensitive layer of company-made H-9040) was directed to the substrate, and the base film side was brought into contact with the roll, and the protective film was pressure-bonded while being peeled. At this time, the laminating roll speed was 1.5 m / min, the laminating roll temperature was 110 ° C., and the cylinder pressure of the roll was 0.4 MPa.

  Next, after completion of the pressure bonding, the film is cooled to 23 ° C. and then has a pattern mask on the photosensitive layer (with a stove 21 step tablet and a line width / space width of 1000/100 (resolution, unit: μm)). Pattern mask) and an exposure machine (model EXM-1201, mercury short arc lamp) manufactured by Oak Manufacturing Co., Ltd., and exposure was performed with an energy amount such that the number of remaining step steps after development of the stove 21-step step tablet was 8.0. .

  Subsequently, the photosensitive film was spray developed for 60 seconds (spray pressure: 0.18 MPa) with a 1% by weight aqueous sodium carbonate solution (30 ° C.) to form a resist pattern on the substrate.

  Then, the substrate is immersed in a 100 g / L ammonium persulfate aqueous solution (30 ° C.) for 1 to 10 minutes, and then the resist pattern is removed using a stripping solution (3 wt% NaOH aqueous solution, 45 ° C., spray pressure 0.2 MPa). It peeled and obtained the board | substrate for uneven | corrugated followable | trackability evaluation with a dent depth of 1-10 micrometers (increase every 1 micrometer, 10 types) and a dent width of 100 micrometers.

  After heating the obtained uneven | corrugated followable | trackable evaluation board | substrate to 80 degreeC, using the high temperature laminator (Hitachi Chemical Industries Ltd. make, HLM-3000), Example 1, 2, and Comparative Examples 1, 2 were used for the said board | substrate. Each of the photosensitive films was pressure-bonded while peeling the protective film with the photosensitive layer facing the substrate and the base film side touching the roll. At this time, adjustment was made so that the axis of the laminate roll and the length direction of the recessed portion of the substrate were parallel. The laminating roll speed was 1.5 m / min, the laminating roll temperature was 110 ° C., and the cylinder pressure of the roll was 0.4 MPa.

  Subsequently, after cooling to 23 degreeC, the base film and the cushion layer were peeled from the photosensitive film. Thereafter, a pattern mask (pattern mask having a wiring pattern with a stove 21-step step tablet and a line width / space width of 100/100 (resolution, unit: μm)) is formed on the photosensitive layer, and the uneven follow-up evaluation substrate. The length direction of the dent and the line length direction of the pattern mask are arranged so that they intersect at right angles and are in close contact with each other. The exposure was carried out with an energy amount such that the number of remaining step steps after development of the fur 21-step step tablet was 7.0.

  Subsequently, using a 1% by weight aqueous sodium carbonate solution (30 ° C.), the photosensitive film for circuit formation is spray-developed for 10 seconds (spray pressure: 0.18 MPa) to form a resist pattern on the substrate for evaluating unevenness followability. did.

Then, a cupric chloride etching solution (2 mol / L CuCl ₂ , 2N-HCl aqueous solution, 50 ° C.) is sprayed for 100 seconds (spray pressure 0.2 MPa) to dissolve copper in a portion not protected by the resist ( Etching), and then the resist pattern is peeled off using a stripping solution (3 wt% NaOH aqueous solution, 45 ° C., spray pressure 0.2 MPa), and a copper line is formed on the substrate for unevenness follow-up evaluation. Was made.

  If the photosensitive film does not follow the concavo-convex portion on the substrate for evaluation of concavo-convex followability, as a result, a gap is formed between the resist and the substrate, so that the etching solution is immersed in the intersection of the resist and the dent. If the copper line melts and the level is excessive, the copper line is broken. The depth (μm) of the dent where such a disconnection failure was recognized was evaluated as a factor for unevenness followability. The results are shown in Table 3. It means that the larger the value of the dent depth, the better the followability. Generally, if this value is 3 μm or more, it is considered that the unevenness followability has a level that is not problematic in practical use.

Claims (6)

A photosensitive film comprising a support layer, a cushion layer formed on the support layer, and a photosensitive layer formed on the cushion layer,
A photosensitive film characterized in that the cushion layer contains a resin having a breaking elongation of 1000% or less and a tensile elastic modulus of 10 MPa or less.   The photosensitive film according to claim 1, wherein an interlayer adhesive force between the cushion layer and the photosensitive layer is smaller than an interlayer adhesive force between the support layer and the cushion layer.   The photosensitive layer contains (A) a binder polymer, (B) a photopolymerizable compound having at least one polymerizable ethylenically unsaturated bond in the molecule, and (C) a photopolymerization initiator. The photosensitive film according to claim 1, comprising a photosensitive resin composition. A laminating step of arranging the photosensitive film according to any one of claims 1 to 3 so that the photosensitive layer, the cushion layer, and the support layer are laminated on a circuit forming substrate in this order;
An exposure step of irradiating a predetermined portion of the photosensitive layer with actinic rays to form a photocured portion in the photosensitive layer;
A peeling step of removing the support layer and the cushion layer by peeling from the photosensitive film;
A developing step for removing the photosensitive layer other than the photocured portion;
The printed wiring board manufacturing method characterized by including this.   The exposure step is performed after the laminating step and before the peeling step, and in the exposure step, the actinic ray is irradiated to a predetermined portion of the photosensitive layer through the support layer and the cushion layer. The method for producing a printed wiring board according to claim 4.   The exposure step is performed after the peeling step and before the developing step, and in the exposure step, the actinic rays are exposed to the photosensitive layer in a state where the support layer and the cushion layer are peeled off. The method for manufacturing a printed wiring board according to claim 4, wherein a predetermined portion of the layer is irradiated.