JP2018125378A - Dry film, cured product, printed wiring board, and method for manufacturing cured product - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide: a dry film which enables the formation of such a cured product that unevenness is little in its surface even when cured by heat, without peeling the film; a cured product of a resin layer of the dry film; a printed wiring board having the cured product; and a method for manufacturing the cured product.SOLUTION: Disclosed are a dry film and the others. The dry film is arranged by laminating a resin layer on a film. The resin layer is a thermosetting resin layer including a thermosetting resin and a hardening agent. The different in heat change rate (%) of the length of the film between lengthwise and crosswise directions thereof is 2.7% or less. As the hardening agent, at least two kinds selected from a phenol resin, a cyanate ester resin and an active ester resin are included.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a dry film, a cured product, a printed wiring board, and a method for producing the cured product.

  Conventionally, a dry film (laminated film) has been used as one of means for forming a protective film or an insulating layer such as a solder resist or an interlayer insulating layer provided on a printed wiring board used in an electronic device or the like (for example, Patent Documents). 1). A dry film has a resin layer obtained by applying a resin composition having desired characteristics on a carrier film and then a drying process, and generally protects the surface opposite to the carrier film. The protective film is further distributed on the market. After the resin layer of the dry film is adhered to the substrate (hereinafter also referred to as “laminate”), the printed wiring board having the protective film and the insulating layer as described above can be manufactured by performing patterning and curing treatment. .

JP, 2015-010179, A

  Laser processing is performed as one of the methods for patterning a cured product of a resin layer formed using a dry film. Conventionally, after removing the protective film and laminating the resin layer on the base material, the carrier film is peeled off, followed by thermosetting and laser processing. However, in recent years, from the viewpoint of protection of the resin surface from dust and the like and flatness of the resin surface, patterning is performed by performing thermosetting and laser irradiation without peeling off the carrier film. In addition, laser processing without peeling off the carrier film, and by absorbing the laser to some extent by the carrier film, a technique for making the opening diameter by laser processing finer or reducing damage to the cured product by the laser is also attracting attention. .

  However, when heat curing is performed without peeling off the carrier film, there is a problem that the uniformity of the surface of the cured product is impaired and unevenness occurs on the surface. Such unevenness becomes particularly noticeable after the desmear treatment. As a result, the properties of the cured product such as peel strength and reliability are also impaired.

  Accordingly, an object of the present invention is to provide a dry film capable of forming a cured product with less unevenness on the surface even when thermally cured without peeling off the film, a cured product of the resin layer of the dry film, and a print comprising the cured product It is providing the wiring board and the manufacturing method of hardened | cured material.

  The inventors first reviewed the composition of the resin layer and attempted to achieve the above-mentioned problem, but it was difficult to sufficiently reduce the unevenness of the cured product surface while maintaining the desired properties of the cured product. It was. Accordingly, as a result of further intensive studies in view of the above, the present inventors have found that the above problem can be solved by adjusting the rate of thermal change of the length of the film that remains attached to the resin layer during thermosetting, and the present invention. It came to complete.

  That is, the dry film of the present invention is a dry film in which a resin layer is laminated on a film, and the resin layer is a thermosetting resin layer containing a thermosetting resin and a curing agent. The difference in thermal change rate (%) between the length in the vertical direction and the horizontal direction is 2.7% or less, and the curing agent is at least any two selected from phenol resins, cyanate ester resins and active ester resins It is characterized by including the above.

  In the dry film of the present invention, the thermosetting resin is preferably an epoxy compound.

  In the dry film of the present invention, it is preferable that the resin layer contains a phenol resin as the curing agent, and further contains at least one of a cyanate ester resin and an active ester resin.

  In the dry film of the present invention, it is preferable that the difference in thermal change rate between the length in the vertical direction and the horizontal direction of the film is 2.1% or less.

  The cured product of the present invention is obtained by curing the resin layer of the dry film.

  The printed wiring board of the present invention comprises the cured product.

  The manufacturing method of the hardened | cured material of this invention comprises the process of laminating the resin layer of the said dry film on a base material, and thermosetting, without peeling the said film, and obtaining hardened | cured material.

  ADVANTAGE OF THE INVENTION According to this invention, the dry film which can form the hardened | cured material with little nonuniformity on the surface even if it heat-hardens without peeling off a film, the hardened | cured material of the resin layer of this dry film, and the printed wiring provided with this hardened | cured material A plate and a method for producing a cured product can be provided.

It is the schematic which shows the longitudinal direction (MD direction) and width direction (TD direction) of a film. It is a schematic sectional drawing which shows typically one embodiment of the dry film of this invention. It is a schematic sectional drawing which shows typically another embodiment of the dry film of this invention. It is the schematic which shows the relationship between the test piece (a), (b) used for the measurement of the rate of thermal change in an Example, and the longitudinal direction (MD direction) and width direction (TD direction) of a film.

<Dry film>
The dry film of the present invention is a dry film in which a resin layer is laminated on a film, and the resin layer is a thermosetting resin layer containing a thermosetting resin and a curing agent, and the longitudinal direction of the film And the difference in thermal change rate (%) in the length in the lateral direction is 2.7% or less, and the curing agent is at least any two selected from phenol resin, cyanate ester resin and active ester resin. It is characterized by including. Although the detailed mechanism is not clear, the film has a longitudinal direction (also referred to as MD (Machine Direction) direction, machine direction, flow direction) and a width direction (TD direction (Transverse Direction), also referred to as vertical direction) in the manufacturing process. Since the film has anisotropy, the thermal shrinkage or thermal expansion of the film also varies depending on the direction, and when the film is heated while attached to the resin layer, the resin layer surface flows along with the deformation of the film, and the resin composition on the resin layer surface It is considered that the main cause of the unevenness of the surface is that the object is cured in a separated state. In the dry film of the present invention, the unevenness of the surface is suppressed by adjusting the distortion of thermal contraction / thermal expansion in the vertical and horizontal directions of the film, that is, the difference in the rate of thermal change to 2.7% or less. Making it possible.

  FIG. 1 is a schematic view showing the longitudinal direction and the width direction of the film. Since the difference in the heat change rate is a “difference”, either the longitudinal direction or the transverse direction may be the longitudinal direction of the film, but in this specification, the longitudinal direction is the longitudinal direction, and the width direction is The horizontal direction.

  The surface unevenness occurs more significantly when the thermosetting behavior of the resin layer is complicated, for example, when the resin layer contains different curing agents. In particular, when the curing agent contains at least any two or more selected from a phenol resin, a cyanate ester resin, and an active ester resin, unevenness of the surface tends to occur. According to the dry film of the present invention, surface unevenness can be suppressed even in such a case.

  In the present invention, the rate of thermal change (%) in the longitudinal and lateral lengths of the film is the thermosetting temperature of the thermosetting resin layer, that is, the temperature at which the thermosetting resin layer is thermoset (mainly 180 to 200 ° C.), and after heat treatment at 180 ° C. by the tensile load method. For the measurement, a TMA (thermomechanical analyzer), for example, TMA6100 manufactured by Seiko Instruments Inc. can be used. The heat treatment at the time of measurement need not be a sudden temperature rise, and for example, it is preferable to apply a heat treatment for thermosetting the thermosetting resin layer. As specific measurement conditions, the film was annealed to remove thermal distortion under the condition of a load of 2 g, then heated to 30 ° C. → 100 ° C. (temperature increase rate: 15 ° C./min), then 100 What is necessary is just to measure the length after hold | maintaining at 100 degreeC for 30 minutes, heating up from 100 degreeC-> 180 degreeC (temperature increase rate of 5 degree-C / min), and hold | maintaining at 180 degreeC for 30 minutes. The length before the heat treatment is defined as the length at the measurement start temperature at 30 ° C. before the heat treatment. As the annealing treatment, the same treatment as the heat treatment may be performed in advance for one cycle. In addition, the measurement of the heat change rate of a film is performed by film alone without laminating a resin layer on the film.

  FIG. 2 is a schematic sectional view showing an embodiment of the dry film of the present invention. The resin layer 22 is a dry film 21 having a two-layer structure formed on a film (carrier film) 23. Further, as shown in FIG. 3, a resin layer 32 is formed on a film (carrier film) 33, and a film (protective film) 34 is further laminated to protect the surface of the resin layer 32. The dry film 31 may be used. If necessary, another resin layer may be provided between the film and the resin layer. In addition, the resin layer of the dry film of the present invention may be one layer or two or more layers.

[the film]
For example, in the case of a dry film having a three-layer structure having a resin layer sandwiched between a carrier film and a protective film as shown in FIG. 3, in many cases, the protective film is peeled off for protection. Lamination is performed such that the surface of the resin layer on the side in contact with the film is in contact with the substrate. However, the carrier film may be peeled and laminated so that the surface of the resin layer on the side in contact with the carrier film is in contact with the substrate. In the present invention, a film having a difference in thermal change rate (%) between the length in the vertical direction and the horizontal direction of 2.7% or less is a film that is not peeled off from the resin layer during thermosetting (in other words, a film that is not peeled off during lamination) ) And may be either a carrier film or a protective film. Preferably, it is a carrier film.

  The smaller the difference in the rate of thermal change between the length of the film in the vertical direction and the length in the horizontal direction, the better. The cured product with less unevenness on the surface can be obtained. More preferably, it is 2.1% or less.

The heat change rate of the length in the longitudinal direction (MD direction) of the film is preferably −3 to 0%, more preferably −2.6 to 0%. The heat change rate of the length in the width direction (TD direction) of the film is preferably 1.5% or less, and more preferably 0% or less.
The thickness of a film is 10-100 micrometers, for example, Preferably, it is 20-50 micrometers.

The raw material of the film is not particularly limited. For example, in addition to polyester resins such as polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polybutylene naphthalate (PBN), and polypropylene terephthalate (PPT), isophthalic acid, orthophthalic acid, PBT resin copolymerized with dicarboxylic acid such as naphthalenedicarboxylic acid, biphenyldicarboxylic acid, cyclohexanedicarboxylic acid, adipic acid, azelaic acid, sebacic acid, ethylene glycol, 1,3-propylene glycol, 1,2-propylene glycol, Neopentyl glycol, 1,5-pentanediol, 1,6-hexanediol, diethylene glycol, cyclohexanediol, polyethylene glycol, polytetramethylene glycol, poly Diol components such as turbo sulfonate diol copolymerized PBT resin, polyimide, polyamide-imide, polyethylene, polytetrafluoroethylene, polypropylene, thermoplastic resins such as polystyrene. The film material may contain conventionally known additives such as a lubricant, a stabilizer, a colorant, an antioxidant, an antistatic agent, and an ultraviolet absorber as necessary.
As the lubricant type, in addition to inorganic lubricants such as silica, calcium carbonate, and alumina, organic lubricants are preferable, silica and calcium carbonate are more preferable, and calcium carbonate is particularly preferable. By these, transparency and slipperiness can be expressed.
The lower limit of the lubricant concentration is preferably 100 ppm, and if it is 100 ppm or more, the slipperiness becomes good. The upper limit of the lubricant concentration is preferably 20000 ppm, and transparency is good when it is 20000 ppm or less.

(Film production method)
The film used for the dry film of the present invention may be any film as long as the difference in heat change rate is 2.7% or less as described above, and can be obtained by a known method. For example, the polyester film production method includes a melt-kneading step in which a polyester resin is melt-kneaded with a biaxial extruder, and a stretching step in which the melt-kneaded polyester resin is extruded to stretch and form a biaxially stretched polyester film. Is preferred. Hereinafter, each step will be described.

(Melting and kneading process)
First, a polyester resin is supplied to an extruder and kneaded and melted. The extruder is preferably a twin screw extruder. The screw diameter is not particularly limited. As for L / D which is ratio of screw length L (mm) and screw diameter D (mm), 10-70 are preferable.
Q / Ns, which is a ratio between the extrusion discharge speed Q (kg / h) and the screw rotation speed Ns (rpm), is preferably melt-kneaded in the range of 1.0 to 7.5.
The screw used in the twin-screw extruder has a kneading block, and it is preferable to incorporate the kneading block with respect to the screw length L in a range of 4.0 to 14.0%.
The cylinder temperature is preferably 250 to 310 ° C.
Two or more vent holes connected to the extruder cylinder space are preferably provided. The degree of vacuum in the cylinder space in the extruder deaerated from the vent hole is preferably 1 to 100 hPa.
The extrusion discharge speed Q (kg / h) and the screw rotation speed Ns are not particularly limited.
The shape of the kneading block is not particularly limited, although it is preferable to incorporate at least one kneading block having a shape that causes the polymer to flow backward in the polymer flow direction in consideration of appropriate kneading of the polyester resin.
Each screw rotation direction of the twin-screw extruder may be the same direction rotation or a different direction rotation. From the viewpoint of high self-cleaning properties, it is preferable that the rotation direction of each screw is the same direction. The meshing of each screw of the twin screw extruder may be any of a meshing type, a partial meshing type, and a non-meshing type.
After kneading and melting, foreign matter is removed and the amount of extrusion is leveled through a filter and a gear pump, and the sheet is discharged from a T-die onto a cooling drum. In that case, an electrostatic contact method in which a cooling drum and a polyester resin are brought into close contact with each other by static electricity using an electrode applied with a high voltage is preferably used.

(Stretching process)
Next, the polyester resin melt-kneaded is extruded to stretch-mold the polyester film. As one of the methods, there is a method of obtaining a biaxially stretched polyester film by melt-kneading a polyester resin with a biaxial extruder directly connected to a film forming machine and extruding it into a sheet.
The stretching method can be simultaneous biaxial stretching or sequential biaxial stretching.
The stretching temperature in the longitudinal stretching direction (hereinafter referred to as MD) is preferably 40 to 100 ° C. The MD draw ratio is preferably 2.5 to 5 times.
The stretching temperature in the transverse stretching direction (hereinafter referred to as TD) is preferably 40 to 100 ° C. The TD stretch ratio is 2.5 to 5 times. It is preferable that it is 150-250 degreeC of TD heat setting temperature. The TD relaxation rate is preferably 0.5 to 10%.
The thickness of the polyester film is preferably 3 to 100 μm.

[Resin layer]
The dry film of the present invention has a thermosetting resin layer containing a thermosetting resin and at least two curing agents selected from a phenol resin, a cyanate ester resin, and a curing agent. Moreover, the resin layer may have not only thermosetting property but photo-curing property or photosensitivity as required. The resin layer is generally in a state called a B stage state. A resin layer is obtained through a drying process after applying a thermosetting resin composition to a carrier film. The composition of the thermosetting resin composition is not particularly limited, and is a thermosetting resin used for forming a protective layer or an insulating layer provided on a printed wiring board such as a conventionally known solder resist, interlayer insulating layer and coverlay. A resin composition can be used.

  Although the film thickness of a resin layer is not specifically limited, The film thickness after drying should just be 1-200 micrometers.

  The thermosetting resin is not particularly limited, and known and commonly used thermosetting resins such as isocyanate compounds, blocked isocyanate compounds, amino resins, benzoxazine resins, carbodiimide resins, cyclocarbonate compounds, epoxy compounds, polyfunctional oxetane compounds, and episulfide resins. Resin can be used. Among these, an epoxy compound, a polyfunctional oxetane compound, a compound having two or more thioether groups in the molecule, that is, an episulfide resin is preferable, and an epoxy compound is more preferable.

  The epoxy compound is a compound having an epoxy group, and any conventionally known one can be used. Examples thereof include a bifunctional epoxy compound having two epoxy groups in the molecule and a polyfunctional epoxy compound having many epoxy groups in the molecule. Note that a hydrogenated epoxy compound may be used.

  Examples of the epoxy compound include bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol E type epoxy resin, hydrogenated bisphenol A type epoxy resin, brominated bisphenol A type epoxy resin, bisphenol S type epoxy resin, and phenol novolac type. Epoxy resin, cresol novolac type epoxy resin, bisphenol A novolac type epoxy resin, biphenyl type epoxy resin, naphthol type epoxy resin, naphthalene type epoxy resin, dicyclopentadiene type epoxy resin, triphenylmethane type epoxy resin, alicyclic epoxy Resin, aliphatic chain epoxy resin, phosphorus-containing epoxy resin, anthracene type epoxy resin, norbornene type epoxy resin, adamantane type epoxy resin, fluorene type epoxy resin Resins, aminophenol type epoxy resin, amino cresol type epoxy resin, alkylphenol type epoxy resin or the like is used. These epoxy compounds can be used alone or in combination of two or more.

  The epoxy compound may be a solid epoxy resin, a semi-solid epoxy resin, or a liquid epoxy resin. In this specification, a solid epoxy resin refers to an epoxy resin that is solid at 40 ° C., and a semi-solid epoxy resin refers to an epoxy resin that is solid at 20 ° C. and is liquid at 40 ° C. Means an epoxy resin that is liquid at 20 ° C. Judgment of liquid state shall be made in accordance with the second “Liquid Confirmation Method” of the Ministerial Ordinance on Dangerous Goods Testing and Properties (Ministry of Local Government Ordinance No. 1 of 1989).

  A thermosetting resin can be used individually by 1 type or in combination of 2 or more types. The compounding amount of the thermosetting resin is preferably 10 to 50% by mass, more preferably 10 to 40% by mass, and more preferably 10 to 35% by mass based on the total amount of the resin layer of the dry film excluding the solvent. Is even more preferred. Moreover, since the glass transition temperature (Tg) and crack resistance of hardened | cured material become more favorable, the compounding quantity of a liquid epoxy resin in the case of mix | blending a liquid epoxy resin becomes 0-45 mass per thermosetting resin total mass. % Is preferable, and 0 to 30% by mass is more preferable.

  The resin layer contains at least two kinds selected from a phenol resin, a cyanate ester resin, and an active ester resin as a curing agent. Here, the dielectric loss tangent after humidification can be lowered by containing at least one of a cyanate ester resin and an active ester resin. Further, it is more preferable to combine a phenol resin with at least one of a cyanate ester resin and an active ester resin, and both low dielectric loss tangent can be achieved while having an appropriate roughness and peel strength. Moreover, the crack tolerance at the time of the thermal cycle after reflow improves by containing cyanate ester resin. The curing agent preferably has a structure of at least one of a biphenyl skeleton and a naphthol skeleton.

  Examples of the phenol resin include phenol novolac resin, alkylphenol volac resin, bisphenol A novolac resin, dicyclopentadiene type phenol resin, Xylok type phenol resin, terpene modified phenol resin, cresol / naphthol resin, polyvinylphenols, phenol / naphthol resin. , Α-naphthol skeleton-containing phenol resin, triazine skeleton-containing cresol novolak resin, biphenyl aralkyl type phenol resin, zylock type phenol novolak resin and the like can be used singly or in combination of two or more. . Among the phenol resins, the hydroxyl group equivalent is 100 g / eq. The above are preferable, and 150 g / eq. The above is more preferable. Hydroxyl equivalent weight is 100 g / eq. Examples of the phenol resin include dicyclopentadiene skeleton phenol novolak resin (GDP series, Gunei Chemical Co., Ltd.), zylock type phenol novolac resin (MEH-7800, manufactured by Meiwa Kasei Co., Ltd.), biphenyl aralkyl type novolak resin (MEH). -7851, manufactured by Meiwa Kasei Co., Ltd.), naphthol aralkyl type curing agent (SN series, manufactured by Nippon Steel & Sumikin Co., Ltd.), triazine skeleton-containing cresol novolac resin (LA-3018-50P, manufactured by DIC), and the like. A phenol resin can be used individually by 1 type or in combination of 2 or more types.

  The cyanate ester resin is a compound having two or more cyanate ester groups (—OCN) in one molecule. Any conventionally known cyanate ester resins can be used. Examples of the cyanate ester resin include phenol novolac type cyanate ester resin, alkylphenol novolak type cyanate ester resin, dicyclopentadiene type cyanate ester resin, bisphenol A type cyanate ester resin, bisphenol F type cyanate ester resin, and bisphenol S type cyanate ester resin. Is mentioned. Further, it may be a prepolymer partially triazine. Cyanate ester resin can be used individually by 1 type or in combination of 2 or more types.

  The active ester resin is a resin having two or more active ester groups in one molecule. The active ester resin can generally be obtained by a condensation reaction between a carboxylic acid compound and a hydroxy compound. Among these, an active ester compound obtained by using a phenol compound or a naphthol compound as the hydroxy compound is preferable. Examples of phenol compounds or naphthol compounds include hydroquinone, resorcin, bisphenol A, bisphenol F, bisphenol S, phenolphthaline, methylated bisphenol A, methylated bisphenol F, methylated bisphenol S, phenol, o-cresol, m-cresol, p-cresol, catechol, α-naphthol, β-naphthol, 1,5-dihydroxynaphthalene, 1,6-dihydroxynaphthalene, 2,6-dihydroxynaphthalene, dihydroxybenzophenone, trihydroxybenzophenone, tetrahydroxybenzophenone, phloroglucin, benzenetriol , Dicyclopentadienyl diphenol, phenol novolac and the like. The active ester resin may be naphthalenediol alkyl / benzoic acid type. An active ester resin can be used individually by 1 type or in combination of 2 or more types.

  The said resin layer may contain another hardening | curing agent in the range which does not impair the effect of this invention. Examples of other curing agents include polycarboxylic acids and acid anhydrides thereof, maleimide compounds, alicyclic olefin polymers, and the like. Especially, the crack tolerance at the time of the thermal cycle after reflow improves by containing a maleimide compound. The maleimide compound is a compound having a maleimide skeleton, and any conventionally known compound can be used. The maleimide compound preferably has two or more maleimide skeletons, and N, N′-1,3-phenylene dimaleimide, N, N′-1,4-phenylene dimaleimide, N, N′-4,4- Diphenylmethane bismaleimide, 1,2-bis (maleimide) ethane, 1,6-bismaleimide hexane, 1,6-bismaleimide- (2,2,4-trimethyl) hexane, 2,2′-bis- [4- (4-maleimidophenoxy) phenyl] propane, 3,3′-dimethyl-5,5′-diethyl-4,4′-diphenylmethane bismaleimide, 4-methyl-1,3-phenylenebismaleimide, bis (3-ethyl -5-methyl-4-maleimidophenyl) methane, bisphenol A diphenyl ether bismaleimide, polyphenylmethanemaleimide, Beauty and more preferably at least any one of diamines condensates with these oligomers and maleimide skeleton. The said oligomer is an oligomer obtained by condensing the maleimide compound which is a monomer of the above-mentioned maleimide compounds. A maleimide compound can be used individually by 1 type or in combination of 2 or more types.

  In the curing agent, the ratio of the functional group capable of thermosetting reaction such as an epoxy group of the thermosetting resin and the functional group in the curing agent that reacts with the functional group is the functional group of the curing agent / thermosetting reaction. It is preferable to mix | blend in the ratio which becomes functional group (equivalent ratio) = 0.2-2.0 which can be. By setting the functional group of the curing agent / functional group capable of thermosetting reaction (equivalent ratio) within the above range, the surface of the resin can have an appropriate roughness in the desmear process. More preferably, the functional group of the curing agent / functional group capable of thermosetting reaction (equivalent ratio) = 0.2 to 1.5, and more preferably the functional group of the curing agent / functional group capable of thermosetting reaction ( Equivalent ratio) = 0.3 to 1.0. When the functional group equivalent (g / eq.) Of the phenol resin, cyanate ester resin, active ester resin, and maleimide compound is 200 or more, warpage can be reduced.

  As a curing agent, the compounding ratio of phenol resin: cyanate ester resin and / or active ester resin in a combination of phenol resin and at least one of cyanate ester resin and active ester resin is 1: 0.1 in terms of mass. 15 is preferable, and 1: 1.0 to 10 is more preferable.

  Specific examples of the thermosetting resin composition forming the resin layer include a thermosetting resin composition, a photocurable thermosetting resin composition, and a photocurable thermosetting resin containing a photopolymerization initiator. Composition, photocurable thermosetting resin composition containing photobase generator, photocurable thermosetting resin composition containing photoacid generator, negative photocurable thermosetting resin composition and positive Type photosensitive thermosetting resin composition, alkali development type photocurable thermosetting resin composition, solvent development type photocurable thermosetting resin composition, swelling release type thermosetting resin composition, dissolution release type heat Although a curable resin composition is mentioned, it is not limited to these.

(Thermosetting resin composition)
As an example of the thermosetting resin composition, a resin composition containing no thermosetting component and containing a thermosetting resin will be described below.

  It is preferable to add a filler to the thermosetting resin composition, and the physical strength of the resulting cured product can be increased. Moreover, the thermal characteristic of a dry film can be improved by match | combining heat intensity with conductor layers, such as copper around the insulating layer, by mix | blending a filler. As the filler, conventionally known inorganic fillers and organic fillers can be used and are not limited to specific ones, but inorganic fillers that suppress the curing shrinkage of the coating film and contribute to the improvement of properties such as adhesion and hardness are preferred. Examples of inorganic fillers include silica such as barium sulfate, barium titanate, amorphous silica, crystalline silica, fused silica, and spherical silica, talc, clay, Neuburg silica particles, boehmite, magnesium carbonate, calcium carbonate, and titanium oxide. , Body pigments such as aluminum oxide, aluminum hydroxide, silicon nitride, aluminum nitride, calcium zirconate and metal powders such as copper, tin, zinc, nickel, silver, palladium, aluminum, iron, cobalt, gold, platinum Can be mentioned. The inorganic filler is preferably spherical particles. It is preferable that the average particle diameter of a filler is 0.1-10 micrometers. In the present specification, the average particle size of the filler is not only the particle size of the primary particles but also the average particle size including the particle size of the secondary particles (aggregates). The average particle size can be determined by a laser diffraction particle size distribution measuring device. An example of a measuring apparatus using the laser diffraction method is Nanotrac wave manufactured by Nikkiso Co., Ltd.

  The inorganic filler may be surface-treated. As the surface treatment, a surface treatment that does not introduce an organic group such as a surface treatment with a coupling agent or an alumina treatment may be performed.

  A filler may be used individually by 1 type and may be used as a mixture of 2 or more types. The blending amount of the filler is preferably 10 to 90% by mass, and more preferably 30 to 80% by mass, based on the total amount of the resin layer of the dry film excluding the solvent. When the blending amount of the filler is 10% by mass or more, thermal expansion is suppressed and heat resistance is improved. On the other hand, when it is 90% by mass or less, generation of cracks can be suppressed.

  The thermosetting resin composition can further contain a thermoplastic resin in order to improve the mechanical strength of the resulting cured film. The thermoplastic resin is preferably soluble in a solvent. When it is soluble in the solvent, the flexibility of the dry film is improved, and the generation of cracks and powder falling can be suppressed. As the thermoplastic resin, use is made of thermoplastic polyhydroxy polyether resin, phenoxy resin that is a condensate of epichlorohydrin and various bifunctional phenolic compounds, or hydroxyl group of hydroxy ether part present in the skeleton of various acid anhydrides and acid chlorides. And esterified phenoxy resin, polyvinyl acetal resin, polyamide resin, polyamideimide resin, block copolymer and the like. A thermoplastic resin can be used individually by 1 type or in combination of 2 or more types.

  The blending amount of the thermoplastic resin is 0.5 to 20% by mass, preferably 0.5 to 10% by mass, based on the total amount of the resin layer excluding the solvent. When the blending amount of the thermoplastic resin is out of the above range, it becomes difficult to obtain a uniform roughened surface state.

  Furthermore, the thermosetting resin composition can contain rubber-like particles as necessary. Examples of such rubber-like particles include polybutadiene rubber, polyisopropylene rubber, urethane-modified polybutadiene rubber, epoxy-modified polybutadiene rubber, acrylonitrile-modified polybutadiene rubber, carboxyl group-modified polybutadiene rubber, acrylonitrile butadiene rubber modified with a carboxyl group or a hydroxyl group, and These crosslinked rubber particles, core-shell type rubber particles, and the like can be mentioned, and one kind can be used alone or two or more kinds can be used in combination. These rubber-like particles are added to improve the flexibility of the resulting cured film, improve crack resistance, enable surface roughening treatment with an oxidizing agent, and improve the adhesion strength with copper foil, etc. Is done.

  The average particle size of the rubber-like particles is preferably in the range of 0.005 to 1 μm, and more preferably in the range of 0.2 to 1 μm. The average particle size of the rubber-like particles in the present invention can be determined by a laser diffraction particle size distribution measuring device. For example, rubber-like particles are uniformly dispersed in an appropriate organic solvent by ultrasonic waves, etc., and a particle size distribution of the rubber-like particles is created on a mass basis using Nanotrac wave manufactured by Nikkiso Co., Ltd. It can be measured by doing.

  The compounding amount of the rubber-like particles is preferably 0.5 to 10% by mass and more preferably 1 to 5% by mass based on the total amount of the resin layer excluding the solvent. In the case of 0.5% by mass or more, crack resistance is obtained, and the adhesion strength with a conductor pattern or the like can be improved. When the content is 10% by mass or less, the coefficient of thermal expansion (CTE) decreases, the glass transition temperature (Tg) increases, and the curing characteristics are improved.

  The thermosetting resin composition can contain a curing accelerator. The curing accelerator is for accelerating the thermosetting reaction, and is used for further improving properties such as adhesion, chemical resistance, and heat resistance. Specific examples of such curing accelerators include imidazole and derivatives thereof; guanamines such as acetoguanamine and benzoguanamine; diaminodiphenylmethane, m-phenylenediamine, m-xylenediamine, diaminodiphenylsulfone, dicyandiamide, urea, urea derivatives, Polyamines such as melamine and polybasic hydrazides; organic acid salts and / or epoxy adducts thereof; amine complexes of boron trifluoride; ethyldiamino-S-triazine, 2,4-diamino-S-triazine, 2,4- Triazine derivatives such as diamino-6-xylyl-S-triazine; trimethylamine, triethanolamine, N, N-dimethyloctylamine, N-benzyldimethylamine, pyridine, N-methylmorpholine, hexa (N-methyl) Amines such as lamin, 2,4,6-tris (dimethylaminophenol), tetramethylguanidine, m-aminophenol; polyphenols such as polyvinylphenol, polyvinylphenol bromide, phenol novolac, alkylphenol novolac; tributylphosphine, tri Organic phosphines such as phenylphosphine and tris-2-cyanoethylphosphine; phosphonium salts such as tri-n-butyl (2,5-dihydroxyphenyl) phosphonium bromide and hexadecyltributylphosphonium chloride; benzyltrimethylammonium chloride and phenyltributylammonium chloride Quaternary ammonium salts such as polybasic acid anhydrides; diphenyliodonium tetrafluoroboroate, triphenyl Photocationic polymerization catalyst such as sulfonium hexafluoroantimonate and 2,4,6-triphenylthiopyrylium hexafluorophosphate; styrene-maleic anhydride resin; equimolar reaction product of phenyl isocyanate and dimethylamine, tolylene diisocyanate, Conventionally known curing accelerators such as an equimolar reaction product of an organic polyisocyanate such as isophorone diisocyanate and dimethylamine, and a metal catalyst can be used. Among the curing accelerators, phosphonium salts are preferred because BHAST resistance is obtained.

  A hardening accelerator can be used individually by 1 type or in mixture of 2 or more types. The use of a curing accelerator is not essential, but particularly when it is desired to accelerate the curing, it can be used preferably in the range of 0.01 to 5 parts by mass with respect to 100 parts by mass of the thermosetting resin. In the case of a metal catalyst, 10 to 550 ppm is preferable in terms of metal with respect to 100 parts by mass of the thermosetting resin, and 25 to 200 ppm is preferable.

  The organic solvent is not particularly limited, and examples thereof include ketones, aromatic hydrocarbons, glycol ethers, glycol ether acetates, esters, alcohols, aliphatic hydrocarbons, petroleum solvents, and the like. it can. More specifically, ketones such as methyl ethyl ketone, cyclohexanone, methyl butyl ketone, methyl isobutyl ketone, and methyl ethyl ketone; aromatic hydrocarbons such as toluene, xylene, and tetramethylbenzene; cellosolve, methyl cellosolve, butyl cellosolve, carbitol, methyl Glycol ethers such as carbitol, butyl carbitol, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, propylene glycol monomethyl ether, dipropylene glycol monomethyl ether, dipropylene glycol diethyl ether, triethylene glycol monoethyl ether Class: ethyl acetate, butyl acetate, isobutyl acetate, ethylene glycol monoethyl ester Esters such as teracetate, dipropylene glycol methyl ether acetate, propylene glycol methyl ether acetate, propylene glycol ethyl ether acetate, propylene glycol butyl ether acetate; ethanol, propanol, 2-methoxypropanol, n-butanol, isobutyl alcohol, isopentyl alcohol Alcohols such as ethylene glycol and propylene glycol; aliphatic hydrocarbons such as octane and decane; petroleum solvents such as petroleum ether, petroleum naphtha, hydrogenated petroleum naphtha, and solvent naphtha; and N, N-dimethylformamide ( DMF), tetrachloroethylene, turpentine oil and the like. In addition, Maruzen Petrochemical Co., Ltd. Swazol 1000, Swazol 1500, Standard Petroleum Osaka Sales Co., Ltd. Solvesso 100, Solvesso 150, Sankyo Chemical Co., Ltd. Solvent # 100, Solvent # 150, Shell Chemicals Japan Co., Ltd. Shell Sol A100, Shell Sol A150 Organic solvents such as Ipsol No. 100 and Ipsol No. 150 manufactured by Idemitsu Kosan Co., Ltd. may be used. An organic solvent may be used individually by 1 type, and may be used as a 2 or more types of mixture.

  The thermosetting resin composition may further include, as necessary, conventionally known colorants such as phthalocyanine blue, phthalocyanine green, iodine green, disazo yellow, crystal violet, titanium oxide, carbon black, naphthalene black, asbestos, Conventionally known thickeners such as olben, benton and fine silica, adhesion of antifoaming and / or leveling agents such as silicones, fluorines and polymers, thiazoles, triazoles and silane coupling agents Conventionally known additives such as imparting agents, flame retardants, titanates, and aluminum can be used.

  As a method for producing a printed wiring board using a dry film having a resin layer composed of a thermosetting resin composition, a conventionally known method may be used. It is preferable to use for the manufacturing method of a printed wiring board provided with the process to harden | cure. For example, in the case of a dry film in which a resin layer is sandwiched between a carrier film and a protective film as shown in FIG. 3, a printed wiring board can be manufactured by the following method. After the protective film is peeled from the dry film and heat laminated to the circuit board on which the circuit pattern is formed, the carrier film is cured without being peeled. The heat curing may be performed in an oven or by a hot plate press. A printed wiring board can be manufactured by forming a pattern or a via hole with laser processing and drilling if necessary at a position corresponding to a predetermined position on the circuit board to expose the circuit wiring. At this time, if there is a component (smear) that cannot be completely removed on the circuit wiring in the pattern or via hole, desmear processing is performed. In the case of the above production method, the carrier film may be peeled off either after laser processing or after desmear treatment.

  The dry film of the present invention can be preferably used for the formation of a permanent protective film of a printed wiring board, and can be preferably used for the formation of a solder resist layer, an interlayer insulating layer, and a cover lay for a flexible printed wiring board. In particular, the dry film of the present invention can be preferably used for applications in which a cured product is formed by thermosetting a resin layer without peeling off the film. You may form a wiring board by bonding a wiring together using the dry film of this invention. It can also be used as a sealing material for semiconductor chips.

  EXAMPLES Hereinafter, the present invention will be specifically described with reference to examples, comparative examples, and test examples of the present invention. However, the present invention is not limited to the following examples. In the following description, “parts” and “%” are all based on mass unless otherwise specified.

(Carrier films A-1 to A-5, R-1, R-2)
The following were used as carrier films A-1 to A-5, R-1, and R-2.
Film A-1: NSP-5 manufactured by Fujimori Kogyo Co., Ltd. (film thickness 25 μm)
Film A-2: NSP-5 manufactured by Fujimori Kogyo Co., Ltd. (film thickness 38 μm)
Film A-3: NSP-5 manufactured by Fujimori Kogyo Co., Ltd. (film thickness 50 μm)
Film A-4: Toray Co., Ltd. therapy H2 (film thickness 38 μm)
Film A-5: SK-1 (film thickness: 38 μm) manufactured by Lintec Corporation
Film R-1: Toyobo E5041 (film thickness 25 μm)
Film R-2: SG-1 manufactured by Panac (film thickness 38 μm)

(Measurement of the difference in heat change rate between the MD and TD lengths of the film)
First, from the polyester film A-1, as a test piece for measuring the thermal change rate in the length in the MD direction and a test piece for measuring the thermal change rate in the length in the TD direction, respectively, as shown in FIG. A test piece (a) having a size of 3 mm (TD) × 10 mm (MD) and a test piece (b) having a size of 10 mm (TD) × 3 mm (MD) were cut and produced.

Next, the thermal change rate of the length of MD direction by the tensile load method of the test piece (a) was measured using TMA6100 by Seiko Instruments Inc. The measurement was performed at a temperature of 30 ° C. to 100 ° C. (temperature increase rate: 15 ° C./min) as an annealing treatment for removing thermal strain while pulling in the long side direction of the test piece in a nitrogen atmosphere under a load of 2 g and in a tensile mode. The temperature was raised, held at 100 ° C. for 30 minutes, heated to 100 ° C. → 180 ° C. (heating rate 5 ° C./minute), held at 180 ° C. for 30 minutes, returned to 30 ° C., and then the temperature was changed to 30 again. The temperature was raised to 100 ° C. → 100 ° C. (temperature increase rate 15 ° C./min), held at 100 ° C. for 30 minutes, heated to 100 ° C. → 180 ° C. (temperature increase rate 5 ° C./min), and then heated at 180 ° C. for 30 minutes. The heat change rate of the length in the MD direction was measured. Thereafter, the test piece (a) was changed to the test piece (b), and the rate of thermal change in length in the TD direction was measured under the same conditions as described above. In addition, the length before heat processing of a film is the value measured in the state which does not apply a load.
Thermal change rate of length in MD direction (%) = 100 × (length in MD direction after heat treatment−length in MD direction before heat treatment) / length in MD direction before heat treatment Length of heat in TD direction Rate of change (%) = 100 × (length in TD direction after heat treatment−length in TD direction before heat treatment) / length in TD direction before heat treatment

Next, the difference (absolute value) is calculated from the heat change rate (%) of the length in the MD direction of the film A-1 and the heat change rate (%) of the length in the TD direction, and the heat of the film A-1 is calculated. The difference (%) in change rate was determined.
Difference in heat change rate of film (%) = | MD heat change rate (%) − TD heat change rate (%) | Also, films A-2 to A-5, R-1, and R-2 are also films. The difference (%) in the rate of thermal change of the film was determined in the same manner as in A-1. The results are as follows.
Difference in thermal change rate of film A-1: 2.00
Difference in thermal change rate of film A-2: 1.75
Difference in heat change rate of film A-3: 1.31
Difference in thermal change rate of film A-4: 2.35
Difference in thermal change rate of film A-5: 2.50
Difference in thermal change rate of film R-1: 3.62
Difference in thermal change rate of film R-2: 3.03

(Examples 1 to 10 and Comparative Examples 1 and 2)
<Production of dry film>
It mix | blends in the ratio (mass part) shown in Table 1 with the various component shown in the Example of following Table 1, and a comparative example, It stirs for 15 minutes with a stirrer, and premixes, Then knead | mixes with a 3 roll mill, A thermosetting resin composition for a thermosetting resin layer was prepared.
Next, using a lip coater, the thermosetting resin composition was applied on the PET film (carrier film) shown in each example and comparative example, dried at a temperature of 90 ° C. for 10 minutes, and heated to a thickness of 40 μm. A curable resin layer was formed on the carrier film to produce a dry film. Next, a protective film (polypropylene film) was laminated on the thermosetting resin layer.

<Creation of a substrate having a thermosetting film>
Next, after the circuit-formed substrate (500 mm × 600 mm × 0.4 mmt (thickness)) is chemically polished, the protective film is peeled off from the dry films prepared in the above-described Examples and Comparative Examples, and a thermosetting resin layer is formed. Laminate so that the side is in contact with the substrate surface, and heat laminate using a vacuum laminator (MVLP-500 manufactured by Meiki Seisakusho Co., Ltd.) under the conditions of pressure: 0.5 MPa, 90 ° C., 1 minute, vacuum: 133.3 Pa. Thus, a substrate (uncured substrate) having a thermosetting resin layer was obtained. Next, it heated at the temperature and time which are shown to an Example and a comparative example in the state which attached the carrier fill with the hot-air circulation type drying furnace, and obtained the thermosetting film.

<Glass transition temperature (Tg) and coefficient of thermal expansion (CTE (α1))>
The dry film produced by the method described in <Preparation of Dry Film> is a batch type dry film obtained by peeling off the protective film on the glossy surface side (copper foil) of GTS-MP foil (Furukawa Circuit Foil Co., Ltd.). Using a vacuum pressure laminator MVLP-500 (manufactured by Meiki Co., Ltd.), the laminate was heated and laminated on the copper foil under the conditions of pressure: 0.5 MPa, 90 ° C., 1 minute, and vacuum: 133.3 Pa.
Next, after heating at 100 ° C. for 30 minutes in a hot-air circulating drying oven, the resin layer was cured at 200 ° C. for 60 minutes, and then the carrier film was peeled off to obtain a cured product. Then, after peeling hardened | cured material from copper foil, the sample was cut out to the measurement size (size of 3 mm x 10 mm), and it used for TMA6100 by Seiko Instruments Inc. In the TMA measurement, the test weight was 5 g, and the sample was heated from room temperature at a heating rate of 10 ° C./min, and was measured twice continuously. The intersection of two tangents having different thermal expansion coefficients in the second round was evaluated as the glass transition temperature (Tg).
-Evaluation of glass transition temperature (Tg) (double-circle): Tg is 170 degreeC or more.
○: Tg is 155 ° C. or higher and lower than 170 ° C.
-Evaluation of thermal expansion coefficient (CTE (α1)) A: Less than 15 ppm.
○: 15 ppm or more and less than 25 ppm.

<Measurement of dielectric loss tangent (Df)>
A cured product having a thickness of 40 μm was obtained by the method described in <Glass Transition Temperature (Tg) and Thermal Expansion Coefficient (CTE (α1))>. About the obtained hardened | cured material, the measurement of the dielectric loss tangent of 10 GHz in 23 degreeC was performed using the SPDR dielectric resonator and the network analyzer (both manufactured by Agilent). Judgment criteria are as follows.
A: Dielectric loss tangent at 10 GHz is less than 0.005.
A: The dielectric loss tangent at 10 GHz is 0.005 or more and less than 0.008.

<Laser workability>
Using a CO ₂ laser processing machine (manufactured by Hitachi Via Mechanics), heat the substrate prepared by the method described in <Preparation of substrate having thermosetting film> so that the top diameter is 40 μm from the top of the carrier film. Via formation was performed on the cured film, laser processing was performed, and then the carrier film was peeled off. Confirmation of the formation state of the vias of the thermosetting film was performed by observing the state of 100 locations with the optical microscope and measuring the via TOP and the via bottom from the surface layer portion of the substrate, and evaluating the laser workability as follows.
○: Formation of a via was confirmed by observation from the surface layer, and the top diameter of the via was 37 to 43 μm and the diameter of the via bottom was 25 to 35 μm, or the top diameter was outside the range of 37 to 43 μm or There are less than three vias whose bottom diameter is outside the range of 25-35 μm.
X: In observation from the surface layer portion, three or more vias having a top diameter outside the range of 37 to 43 μm or a via bottom diameter outside the range of 25 to 35 μm were observed.

<Desmearing (etching spots)>
The carrier film was peeled from the substrate prepared by the method described in <Preparation of substrate having thermosetting film>, and a commercially available wet permanganate desmear (manufactured by ATOTECH) was subjected to desmear treatment under the following conditions. . Specifically, after immersing in Swelling Dip Securigant P for 5 minutes at 60 ° C. (swelling treatment), immerse in Concentrate Compact CP for 20 minutes at 80 ° C. (roughening treatment), and then reduce securigant P500 (reduction treatment). ) Was observed with a SEM (scanning electron microscope) and the desmear property was evaluated as follows.
A: Etching spots are not observed.
○: Etching spots were observed from 1 place to less than 5 places.
X: 5 or more etching spots were observed.

<Peel strength>
Commercially available wet permanganate desmear (manufactured by ATOTECH), electroless copper plating (Sulcup PEA, Sulcup PEA, etc.) on the substrate obtained by peeling the carrier film from the substrate prepared by the method described in <Preparation of substrate having thermosetting film>. Uemura Kogyo Co., Ltd.) and electrolytic copper plating treatment were performed in this order, and the copper plating treatment was performed on the resin layer so that the copper thickness was 25 μm. Next, an annealing treatment was performed at 190 ° C. for 60 minutes in a hot-air circulating drying furnace to obtain a test substrate. A notch with a width of 10 mm and a length of 60 mm is made in the copper plating layer of this test board, one end of the test board is peeled off and sandwiched by a gripping tool, and a 90 ° degree is measured with a desktop tensile tester (EZ-SX, manufactured by Shimadzu Corporation). The peel strength (N / cm) when the 35 mm length of the copper plating layer was peeled off at an angle of 50 mm / min was measured.
○: Peel strength is 3.5 (N / cm) or more.
X: Peel strength is less than 3.5 (N / cm).

<BHAST resistance>
Each dry film having a thickness of 40 μm produced by the method described in <Preparation of Dry Film> on a BT substrate on which comb-shaped electrodes (line / space = 20 microns / 15 microns) are formed is a vacuum laminator (Meiki Seisakusho Co., Ltd.). Using MVLP-500), a thermosetting film was formed on the circuit board by the method described in <Preparation of substrate having thermosetting film>, and then the carrier film was peeled off to prepare an evaluation board. The evaluation substrate was placed in a high-temperature and high-humidity tank under an atmosphere of a temperature of 130 ° C. and a humidity of 85%, charged with a voltage of 5.5 V, and an in-chamber HAST test was performed. The insulation resistance value in the tank at various times of the cured film of the resin layer was evaluated according to the following criteria.
○: 10 ⁸ Ω or more after 300 hours.
×: Less than 10 ⁸ Ω after 300 hours.

<Circuit concealment>
As the circuit board, a double-sided copper-clad laminate (MCL-E-679FGR, manufactured by Hitachi Chemical Co., Ltd.) having a thickness of 400 mm × 300 mm × thickness 0.8 mm on which a circuit pattern with a copper thickness of 20 μm is formed is used. A roughened surface corresponding to a copper etching amount of 1 μm was formed by performing pretreatment using −8100 + CL-8300 (manufactured by MEC). Each dry film having a thickness of 40 μm produced by the method described in <Preparation of Dry Film> was applied to a copper laminating board on which the circuit pattern subjected to the pretreatment was formed by using a vacuum laminator (MVLP manufactured by Meiki Seisakusho Co., Ltd.). -500), a thermosetting film was formed on the circuit board by the method described in <Preparation of substrate having cured film>, and then the carrier film was peeled to obtain a printed wiring board.
About the obtained evaluation board | substrate, the discoloration of the copper circuit from a cured film was confirmed visually, and the concealability of the circuit was evaluated. Judgment criteria are as follows.
A: Discoloration is not confirmed.
○: Slight discoloration was confirmed.

＊１）ｊＥＲ８２８：ビスフェノールＡ型エポキシ樹脂、三菱化学社製、液状エポキシ樹脂
＊２）ｊＥＲ８０７：ビスフェノールＦ型エポキシ樹脂、三菱化学社製、液状エポキシ樹脂
＊３）ＨＰ−４０３２：ナフタレン型エポキシ樹脂、ＤＩＣ社製、半固形エポキシ樹脂
＊４）ＨＰ−７２００Ｌ：ジシクロペンタジエン型エポキシ樹脂、ＤＩＣ社製、軟化点５７〜６８℃、固形エポキシ樹脂
＊５）ＨＦ−１Ｍ：フェノールノボラック樹脂、明和化成社製
＊６）ＬＡ−３０１８：ノボラック樹脂、ＤＩＣ社製
＊７）ＢＡ−３０００：Ｂｉｓ−Ａ型シアネートエステル樹脂、ロンザジャパン社製
＊８）ＥＸＢ−８１００Ｌ：活性エステル樹脂、ＤＩＣ社製
＊９）４ＤＭＡＰｙ：４−ジメチルアミノピリジン、広栄化学工業社製
＊１０）ＣＯ（ＩＩ）：コバルト（ＩＩ）アセチルアセトナート
＊１１）ＦＸ−２９３：フェノキシ樹脂、新日鉄住金化学社製
＊１２）ＳＯ−Ｃ２：シリカＳｉＯ_２、アドマテックス社製
＊１３）ＨＣＡ−ＨＱ：リン系難燃剤、１０−（２，５−ジヒドロキシフェニル）−９，１０−ジヒドロ９−オキサ−１０フォスファフェナントレン−１０−オキサイド、三光社製
＊１４）Ｃ．Ｉ．Ｐｉｇｍｅｎｔ Ｙｅｌｌｏｗ １４７
＊１５）Ｃ．Ｉ．Ｐｉｇｍｅｎｔ Ｂｌｕｅ １５：３

* 1) jER828: bisphenol A type epoxy resin, manufactured by Mitsubishi Chemical Corporation, liquid epoxy resin * 2) jER807: bisphenol F type epoxy resin, manufactured by Mitsubishi Chemical Corporation, liquid epoxy resin * 3) HP-4032: naphthalene type epoxy resin, DIC, semi-solid epoxy resin * 4) HP-7200L: dicyclopentadiene type epoxy resin, DIC, softening point 57-68 ° C., solid epoxy resin * 5) HF-1M: phenol novolac resin, Meiwa Kasei Co., Ltd. * 6) LA-3018: Novolac resin, manufactured by DIC * 7) BA-3000: Bis-A type cyanate ester resin, manufactured by Lonza Japan * 8) EXB-8100L: Active ester resin, manufactured by DIC * 9) 4DMAPy: 4-dimethylaminopyridine, manufactured by Guangei Chemical Industry Co., Ltd. * 10) CO (II Cobalt (II) acetylacetonate * 11) FX-293: phenoxy resin, Nippon Steel Sumitomo Metals Chemical Co., Ltd. * 12) SO-C2: Silica SiO _2, Admatechs Co., Ltd. * 13) HCA-HQ: phosphorus-based flame retardant, 10- (2,5-dihydroxyphenyl) -9,10-dihydro-9-oxa-10 phosphaphenanthrene-10-oxide, manufactured by Sanko Co., Ltd. * 14) C.I. I. Pigment Yellow 147
* 15) C.I. I. Pigment Blue 15: 3

  From the results shown in Tables 1 to 3, it can be seen that in the case of the dry film of the example, a cured product with less unevenness can be formed on the surface, as can be seen from the fact that there are few etching spots after desmearing. On the other hand, in the case of the dry films of Comparative Examples 1 and 2 in which the difference in the rate of thermal change between the longitudinal and lateral lengths of the film is greater than 2.7%, there are many etching spots after desmearing, and the surface of the cured product It can be seen that the unevenness is large.

11 Film 21 Two-layer dry film 22 Resin layer 23 Film (carrier film)
31 Three-layer dry film 32 Resin layer 33 Film (carrier film)
34 Film (Protective film)
41 Film (a) Cutout shape of test piece (a) (b) Cutout shape of test piece (b)

Claims (7)

A dry film in which a resin layer is laminated on a film,
The resin layer is a thermosetting resin layer containing a thermosetting resin and a curing agent,
The difference in heat change rate (%) between the length of the film in the vertical direction and the horizontal direction is 2.7% or less,
A dry film comprising at least any two or more selected from a phenol resin, a cyanate ester resin, and an active ester resin as the curing agent.   The dry film according to claim 1, wherein the thermosetting resin is an epoxy compound.   The dry film according to claim 1, wherein the resin layer contains a phenol resin as the curing agent, and further contains at least one of a cyanate ester resin and an active ester resin.   The dry film according to any one of claims 1 to 3, wherein a difference in heat change rate between the length in the vertical direction and the horizontal direction of the film is 2.1% or less.   A cured product obtained by curing the resin layer of the dry film according to claim 1.   A printed wiring board comprising the cured product according to claim 5. A process for producing a cured product, comprising: laminating a resin layer of the dry film according to any one of claims 1 to 4 on a base material, and thermally curing the film without removing the film to obtain a cured product. Method.

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