Photosensitive resin composition, photosensitive resin film, multilayer printed wiring board and semiconductor package, and method for manufacturing multilayer printed wiring board

Abstract

To provide a photosensitive resin composition having excellent dielectric characteristics and a method for producing the same, a photosensitive resin film using the photosensitive resin composition, a multilayer printed wiring board and a method for producing the same, and a semiconductor package.SOLUTION: The invention relates to: a photosensitive resin composition containing (A) a photopolymerizable compound having an ethylenically unsaturated group and an acidic substituent, (B) an epoxy resin, and (C) an active ester compound, and a method for producing the same, a photosensitive resin film using the photosensitive resin composition, a multilayer printed wiring board and a method for producing the same, and a semiconductor package.SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to a photosensitive resin composition, a photosensitive resin film, a multilayer printed wiring board and a semiconductor package, and a method for manufacturing a multilayer printed wiring board.

Background Art

[0002] In recent years, miniaturization and high performance of electronic devices have advanced, and in multilayer printed wiring boards, the increase in the number of circuit layers and the increase in density due to the miniaturization of wiring have been progressing. In particular, the high density of semiconductor package substrates such as BGA (Ball Grid Array) and CSP (Chip Size Package) on which semiconductor chips are mounted is remarkable, and in addition to the miniaturization of wiring, further thinning of the insulating film and further reduction in the diameter of vias (also referred to as via holes) for interlayer connection are required.

[0003] As a method for manufacturing a printed wiring board that has been conventionally adopted, there is a method for manufacturing a multilayer printed wiring board by a build-up method in which an interlayer insulating layer and a conductor circuit layer are sequentially laminated (for example, see Patent Document 1). In multilayer printed wiring boards, with the miniaturization of circuits, a semi-additive process in which circuits are formed by plating has become the mainstream. In the conventional semi-additive process, for example, (1) a thermosetting resin film is laminated on a conductor circuit, and the thermosetting resin film is cured by heating to form an "interlayer insulating layer". (2) Next, vias for interlayer connection are formed by laser processing, and desmear treatment and roughening treatment are performed by alkaline permanganate treatment or the like. (3) Thereafter, electroless copper plating treatment is performed on the substrate, and after pattern formation using a resist, electroplating of copper is performed to form a copper circuit layer. (4) Next, the resist is peeled off, and flash etching of the electroless layer is performed to form a copper circuit.

[0004] As described above, laser processing has been the mainstream method for forming vias in an interlayer insulating layer formed by curing a thermosetting resin film. However, the reduction of the via diameter by laser irradiation using a laser processing machine is approaching its limit. Furthermore, in the formation of vias by a laser processing machine, it is necessary to form each via hole one by one. When it is necessary to provide a large number of vias due to high density, it takes a long time to form the vias, and there is a problem of poor manufacturing efficiency.

[0005] Under such circumstances, as a method capable of forming a large number of vias at once, a photosensitive resin composition containing an acid-modified vinyl group-containing epoxy resin, a photopolymerizable compound, a photopolymerization initiator, an inorganic filler, and a silane compound, and having an inorganic filler content of 10 to 80% by mass has been proposed to form a plurality of small-diameter vias at once by a photolithography method (see, for example, Patent Document 2).

Prior Art Documents

Patent Documents

[0006]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0007] In Patent Document 2, as one of the problems, suppression of a decrease in the adhesion to copper plating due to using a photosensitive resin composition instead of a conventional thermosetting resin composition as a material for the interlayer insulating layer or the surface protection layer is mentioned. Furthermore, the resolution of vias, and the adhesion to a substrate and chip components made of a silicon material are also problems, and it is stated that these problems have been solved.

[0008] By the way, in recent years, substrate materials have been required to be applicable to fifth-generation mobile communication systems (5G) antennas that use radio waves in frequency bands exceeding 6 GHz and millimeter-wave radars that use radio waves in frequency bands of 30 to 300 GHz. For this purpose, it is necessary to develop a resin composition with further improved dielectric properties in the 10 GHz band and above. However, with the technology of Patent Document 2, it has been difficult to achieve further improvement in dielectric properties while maintaining various properties well.

[0009] Therefore, an object of the present invention is to provide a photosensitive resin composition having excellent dielectric properties and a method for producing the same, a photosensitive resin film using the photosensitive resin composition, a multilayer printed wiring board and a method for producing the same, and a semiconductor package.

Means for Solving the Problems

[0010] As a result of intensive studies to solve the above problems, the present inventors have found that the above problems can be solved by the following present invention, and have completed the present invention. That is, the present invention relates to the following [1] to

[16] . [1] A photosensitive resin composition containing (A) a photopolymerizable compound having an ethylenically unsaturated group and an acidic substituent, (B) an epoxy resin, and (C) an active ester compound. [2] The photosensitive resin composition according to [1] above, wherein the photopolymerizable compound (A) having an ethylenically unsaturated group and an acidic substituent contains an alicyclic structure represented by the following general formula (A-1).

Chemical formula

[10] The photosensitive resin composition according to any one of the above [1] to [9], further containing an inorganic filler (G) in an amount of 10 to 80% by mass based on the total solid content of the photosensitive resin composition.

[11] The photosensitive resin composition according to any one of the above [1] to

[10] , further containing a curing accelerator (H).

[12] The photosensitive resin composition according to any one of [1] to

[11] above, which is used for forming one or more selected from the group consisting of photovias and interlayer insulating layers.

[13] A photosensitive resin film comprising the photosensitive resin composition according to any one of [1] to

[12] above.

[14] A multilayer printed wiring board containing an interlayer insulating layer formed using the photosensitive resin composition according to any one of [1] to

[12] above, or the photosensitive resin film according to

[13] above.

[15] A semiconductor package formed by mounting a semiconductor element on the multilayer printed wiring board according to

[14] above.

[16] A method for manufacturing a multilayer printed wiring board, including the following steps (1) to (4). Step (1): A step of laminating the photosensitive resin film according to

[13] above on one or both sides of a circuit board. Step (2): A step of forming an interlayer insulating layer having vias by exposing and developing the photosensitive resin film laminated in the step (1). Step (3): A step of roughening the vias and the interlayer insulating layer. Step (4): A step of forming a circuit pattern on the interlayer insulating layer. [Effect of the Invention]

[0011] According to the present invention, it is possible to provide a photosensitive resin composition having excellent dielectric properties and a method for manufacturing the same, a photosensitive resin film using the photosensitive resin composition, a multilayer printed wiring board and a method for manufacturing the same, and a semiconductor package. [Brief Description of the Drawings]

[0012]

Figure 1

[0013] In the numerical ranges described in this specification, the upper limit value or the lower limit value of the numerical range may be replaced with the value shown in the examples. Further, in this specification, the content rate of each component in the photosensitive resin composition means the total content rate of the plurality of substances present in the photosensitive resin composition when there are a plurality of substances corresponding to each component, unless otherwise specified. Also, aspects in which the matters described in this specification are arbitrarily combined are also included in the present invention.

[0014] In this specification, the "resin component" means the total amount of components excluding inorganic fillers and diluents that may be contained as necessary, which will be described later. Also, in this specification, the "solid content" refers to the non-volatile content excluding volatile substances such as water and solvents contained in the photosensitive resin composition, and indicates the components that remain without volatilization when the resin composition is dried, and also includes those in a liquid state, a treacle state, and a wax state at room temperature around 25°C.

[0015] In this specification, "(meth)acrylate" means "acrylate or methacrylate", and other similar terms have the same meaning.

[0016] [Photosensitive Resin Composition] The photosensitive resin composition according to one embodiment of the present invention (hereinafter, may be simply referred to as this embodiment) is (A) A photopolymerizable compound having an ethylenically unsaturated group and an acidic substituent, (B) An epoxy resin, and (C) An active ester compound, and is a photosensitive resin composition containing them. In this specification, the above components may be abbreviated as component (A), component (B), component (C), etc., respectively, and other components may also be abbreviated in the same way.

[0017] The photosensitive resin composition of this embodiment has excellent dielectric properties and is suitable for via formation by photolithography (also referred to as photovia formation), and thus is suitable for forming one or more selected from the group consisting of photovias and interlayer insulating layers. Therefore, the present invention also provides a photosensitive resin composition for photovia formation comprising the photosensitive resin composition of this embodiment, and a photosensitive resin composition for interlayer insulating layer comprising the photosensitive resin composition of this embodiment. Note that the photosensitive resin composition of this embodiment is suitable for a negative photosensitive resin composition. Hereinafter, each component that the photosensitive resin composition may contain will be described in detail.

[0018] <(A) Photopolymerizable compound having an ethylenically unsaturated group and an acidic substituent> The photosensitive resin composition of this embodiment contains, as component (A), a photopolymerizable compound having an ethylenically unsaturated group and an acidic substituent. Component (A) may be used alone or in combination of two or more.

[0019] Component (A) is a compound that exhibits photopolymerizability by having an ethylenically unsaturated group. Examples of the ethylenically unsaturated group that component (A) has include functional groups that exhibit photopolymerizability such as vinyl group, allyl group, propargyl group, butenyl group, ethynyl group, phenylethynyl group, maleimide group, nadimide group, (meth)acryloyl group, etc. Among these, from the viewpoints of reactivity and via resolution, the (meth)acryloyl group is preferred.

[0020] Component (A) has an acidic substituent from the viewpoint of enabling alkali development. Examples of the acidic substituent that component (A) has include carboxy group, sulfonic acid group, phenolic hydroxyl group, etc. Among these, from the viewpoint of via resolution, the carboxy group is preferred. The acid value of component (A) is preferably 20 to 200 mgKOH / g, more preferably 40 to 180 mgKOH / g, still more preferably 70 to 150 mgKOH / g, and particularly preferably 90 to 120 mgKOH / g. When the acid value of component (A) is at least the above lower limit value, the solubility of the photosensitive resin composition in a dilute alkaline solution tends to be excellent, and when it is at most the above upper limit value, the cured product tends to have excellent dielectric properties. The acid value of component (A) can be measured by the method described in the examples. Note that two or more types of component (A) having different acid values may be used in combination. In that case, it is preferable that the weight-average acid value of the two or more types of component (A) is within any of the above ranges.

[0021] The weight-average molecular weight (Mw) of component (A) is preferably 600 to 30,000, more preferably 800 to 25,000, and still more preferably 1,000 to 18,000. When the weight-average molecular weight (Mw) of component (A) is within the above range, the adhesiveness, heat resistance, and insulation reliability with electrodeposited copper tend to be excellent. Here, in this specification, the weight-average molecular weight is a value measured according to the following method. <Method for measuring weight-average molecular weight> The weight-average molecular weight was measured with the following GPC measuring apparatus and measuring conditions, and the value converted using the calibration curve of standard polystyrene was taken as the weight-average molecular weight. Also, for the preparation of the calibration curve, 5 sample sets of standard polystyrene (「PStQuick MP-H」 and 「PStQuick B」, manufactured by Tosoh Corporation) were used. (GPC measuring apparatus) GPC apparatus: High-speed GPC apparatus 「HCL-8320GPC」, detector is a differential refractometer or UV, manufactured by Tosoh Corporation Column: Column TSKgel SuperMultipore HZ-H (column length: 15 cm, column inner diameter: 4.6 mm), manufactured by Tosoh Corporation (Measuring conditions) Solvent: Tetrahydrofuran (THF) Measuring temperature: 40 °C Flow rate: 0.35 ml / min Sample concentration: 10 mg / 5 ml of THF Injection volume: 20 μl

[0022] Component (A) preferably contains an alicyclic skeleton from the viewpoint of dielectric properties. As the alicyclic skeleton of component (A), an alicyclic skeleton having 5 to 20 carbon atoms in the ring formation is preferable, an alicyclic skeleton having 5 to 18 carbon atoms in the ring formation is more preferable, an alicyclic skeleton having 6 to 18 carbon atoms in the ring formation is further preferable, an alicyclic skeleton having 8 to 14 carbon atoms in the ring formation is particularly preferable, and an alicyclic skeleton having 8 to 12 carbon atoms in the ring formation is most preferable, from the viewpoints of via resolution, adhesion strength to plated copper, and electrical insulation reliability. Further, from the viewpoints of via resolution, adhesion strength to plated copper, and electrical insulation reliability, the above alicyclic skeleton preferably consists of two or more rings, more preferably consists of 2 to 4 rings, and even more preferably consists of 3 rings. Examples of the alicyclic skeleton of two or more rings include a norbornane skeleton, a decalin skeleton, a bicycloundecane skeleton, a dicyclopentadiene skeleton, and the like. Among these, from the viewpoints of via resolution, adhesion strength to plated copper, and electrical insulation reliability, the dicyclopentadiene skeleton is preferable. From the same viewpoint, component (A) preferably contains an alicyclic structure represented by the following general formula (A-1).

[0023] [Chemical formula] (In the formula, R A1 represents an alkyl group having 1 to 12 carbon atoms and may be substituted anywhere in the above alicyclic structure. m 1 is an integer of 0 to 6. * is a bonding site to another structure.)

[0024] In the above general formula (A-1), examples of the alkyl group having 1 to 12 carbon atoms represented by R A1 include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a t-butyl group, an n-pentyl group, and the like. As the alkyl group, an alkyl group having 1 to 6 carbon atoms is preferable, an alkyl group having 1 to 3 carbon atoms is more preferable, and a methyl group is even more preferable. m1 is an integer from 0 to 6, preferably an integer from 0 to 2, more preferably 0. m 1 When m is an integer from 2 to 6, the plurality of Rs A1 may be the same or different from each other. Further, the plurality of Rs A1 may be substituted on the same carbon atom or on different carbon atoms within the possible range. * is a bonding site to another structure and may be bonded to any carbon atom on the alicyclic skeleton, but is preferably bonded to the carbon atom represented by 1 or 2 and the carbon atom represented by either 3 or 4 in the following general formula (A-1’).

[0025]

Chemical formula

[0026] Component (A) is preferably an acid-modified vinyl group-containing epoxy resin obtained by reacting (a1) an epoxy resin modified with (a2) an ethylenically unsaturated group-containing organic acid [hereinafter sometimes referred to as component (A’).] with (a3) a saturated group or unsaturated group-containing polybasic acid anhydride. Here, “acid-modified” of the acid-modified vinyl group-containing epoxy resin means having an acidic substituent, “vinyl group” means an ethylenically unsaturated group, “epoxy resin” means using an epoxy resin as a raw material, and the acid-modified vinyl group-containing epoxy resin does not necessarily have to have an epoxy group and may not have an epoxy group. Hereinafter, preferred embodiments of component (A) obtained from (a1) an epoxy resin, (a2) an ethylenically unsaturated group-containing organic acid, and (a3) a saturated group or unsaturated group-containing polybasic acid anhydride will be described.

[0027] ((a1) Epoxy resin) (a1) As the epoxy resin, it is preferably an epoxy resin having two or more epoxy groups. (a1) The epoxy resin may be used alone or in combination of two or more. (a1) The epoxy resin is classified into a glycidyl ether type epoxy resin, a glycidyl amine type epoxy resin, a glycidyl ester type epoxy resin, etc. Among these, the glycidyl ether type epoxy resin is preferable.

[0028] (a1) The epoxy resin can be classified into various epoxy resins according to the difference in the main skeleton. For example, it can be classified into an epoxy resin having an alicyclic skeleton, a novolac type epoxy resin, a bisphenol type epoxy resin, an aralkyl type epoxy resin, and other epoxy resins. Among these, the epoxy resin having an alicyclic skeleton and the novolac type epoxy resin are preferable.

[0029] - Epoxy resin having an alicyclic skeleton - Regarding the alicyclic skeleton of the epoxy resin having an alicyclic skeleton, it is explained in the same manner as the alicyclic skeleton of the aforementioned component (A), and the preferable embodiments are also the same. As the epoxy resin having an alicyclic skeleton, the epoxy resin represented by the following general formula (A-2) is preferable.

[0030] [Chemical formula] (In the formula, R A1 represents an alkyl group having 1 to 12 carbon atoms and may be substituted anywhere in the above alicyclic skeleton. R A2 represents an alkyl group having 1 to 12 carbon atoms. m 1 is an integer of 0 to 6, m 2 is an integer of 0 to 3. n is a number of 0 to 50.)

[0031] In the general formula (A-2), R A1 is the same as R A1 in the general formula (A-1), and the preferable embodiments are also the same. R in the general formula (A-2) A2 Examples of the alkyl group having 1 to 12 carbon atoms represented by A2 include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a t-butyl group, an n-pentyl group, and the like. As the alkyl group, an alkyl group having 1 to 6 carbon atoms is preferable, an alkyl group having 1 to 3 carbon atoms is more preferable, and a methyl group is even more preferable. m in the general formula (A-2) 1 is the same as m in the general formula (A-1) 1 and the preferable embodiments are also the same. m in the general formula (A-2) 2 is an integer from 0 to 3, 0 or 1 is preferable, and 0 is more preferable. n in the general formula (A-2) represents the number of repetitions of the structural unit within the parentheses and is a number from 0 to 50. Usually, since the epoxy resin is a mixture of those having different numbers of repetitions of the structural unit within the parentheses, in that case, n is represented by the average value of the mixture. As n, a number from 0 to 30 is preferable.

[0032] As the epoxy resin having an alicyclic skeleton, commercially available products may be used. Examples of the commercially available products include XD-1000 (manufactured by Nippon Kayaku Co., Ltd., trade name), EPICLON (registered trademark) HP-7200 (manufactured by DIC Corporation, trade name), and the like.

[0033] -Novolak type epoxy resin- Examples of the novolak type epoxy resin include bisphenol novolak type epoxy resins such as bisphenol A novolak type epoxy resin, bisphenol F novolak type epoxy resin, bisphenol S novolak type epoxy resin; phenol novolak type epoxy resin, cresol novolak type epoxy resin, biphenyl novolak type epoxy resin, naphthol novolak type epoxy resin, and the like. As the novolak type epoxy resin, an epoxy resin having a structural unit represented by the following general formula (A-3) is preferable.

[0034]

Chemical formula

[0035] R A3 is preferably a hydrogen atom from the viewpoints of the resolution of the via and the adhesiveness to the plated copper. Also, from the same viewpoints, Y A1 is preferably a glycidyl group in each case. The number of structural units of the structural unit represented by the general formula (A-3) in the (a1) epoxy resin having the structural unit is a number of 1 or more, preferably a number of 10 to 100, more preferably a number of 15 to 80, and still more preferably a number of 15 to 70. When the number of structural units is within the above range, the adhesive strength, heat resistance, and insulation reliability tend to be improved. In the general formula (A-3), those in which all Rs A3 are hydrogen atoms and all Ys A1 are glycidyl groups are available commercially as the EXA-7376 series (trade name, manufactured by DIC Corporation), and those in which all Rs A3 are methyl groups and all Ys A1 are glycidyl groups are available commercially as the EPON SU8 series (trade name, manufactured by Mitsubishi Chemical Corporation).

[0036] Examples of the bisphenol type epoxy resin include bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol S type epoxy resin, 3,3’,5,5’-tetramethyl-4,4’-diglycidyloxydiphenylmethane, and the like. Examples of the aralkyl type epoxy resin include phenol aralkyl type epoxy resin, biphenyl aralkyl type epoxy resin, naphthol aralkyl type epoxy resin, and the like. Examples of other epoxy resins include stilbene-type epoxy resins, naphthalene-type epoxy resins, naphthylene ether-type epoxy resins, biphenyl-type epoxy resins, dihydroanthracene-type epoxy resins, cyclohexanedimethanol-type epoxy resins, trimethylol-type epoxy resins, alicyclic epoxy resins, aliphatic chain epoxy resins, heterocyclic epoxy resins, spiro ring-containing epoxy resins, rubber-modified epoxy resins, and the like.

[0037] ((a2) Ethylene-unsaturated group-containing organic acid) As the (a2) ethylene-unsaturated group-containing organic acid, an ethylene-unsaturated group-containing monocarboxylic acid is preferable. Examples of the ethylenically unsaturated group in the (a2) component include the same ones as those listed for the ethylenically unsaturated group in the (A) component. Examples of the (a2) component include acrylic acid derivatives such as acrylic acid, a dimer of acrylic acid, methacrylic acid, β-furfurylacrylic acid, β-styrylacrylic acid, cinnamic acid, crotonic acid, α-cyanocinnamic acid; half-ester compounds that are reaction products of hydroxyl group-containing acrylates and dibasic acid anhydrides; half-ester compounds that are reaction products of vinyl group-containing monoglycidyl ethers or vinyl group-containing monoglycidyl esters and dibasic acid anhydrides, and the like. The (a2) component may be used alone or in combination of two or more.

[0038] The above half-ester compound can be obtained, for example, by reacting one or more ethylene-unsaturated group-containing compounds selected from the group consisting of hydroxyl group-containing acrylates, vinyl group-containing monoglycidyl ethers, and vinyl group-containing monoglycidyl esters with a dibasic acid anhydride. The reaction is preferably carried out with the ethylene-unsaturated group-containing compound and the dibasic acid anhydride in equimolar amounts.

[0039] Examples of the hydroxyl group-containing acrylate used for the synthesis of the above half ester compound include hydroxyethyl (meth)acrylate, hydroxypropyl (meth)acrylate, hydroxybutyl (meth)acrylate, polyethylene glycol mono(meth)acrylate, trimethylolpropane di(meth)acrylate, pentaerythritol tri(meth)acrylate, dipentaerythritol penta(meth)acrylate, and the like. Examples of the vinyl group-containing monoglycidyl ether include glycidyl (meth)acrylate and the like.

[0040] The dibasic acid anhydride used for the synthesis of the above half ester compound may contain a saturated group or an unsaturated group. Examples of the dibasic acid anhydride include succinic anhydride, maleic anhydride, tetrahydrophthalic anhydride, phthalic anhydride, methyltetrahydrophthalic anhydride, ethyltetrahydrophthalic anhydride, hexahydrophthalic anhydride, methylhexahydrophthalic anhydride, ethylhexahydrophthalic anhydride, itaconic anhydride, and the like.

[0041] In the reaction of component (a1) and component (a2), the usage amount of component (a2) is preferably 0.6 to 1.05 equivalents, more preferably 0.7 to 1.02 equivalents, and still more preferably 0.8 to 1.0 equivalents, relative to 1 equivalent of the epoxy group of component (a1). By reacting component (a1) and component (a2) in the above ratio, the photopolymerizability of component (A) is improved, and the resolution of vias of the resulting photosensitive resin composition tends to be improved.

[0042] It is preferable to dissolve component (a1) and component (a2) in an organic solvent and then react them. Examples of the organic solvent include ketones such as methyl ethyl ketone and cyclohexanone; aromatic hydrocarbons such as toluene, xylene, and tetramethylbenzene; glycol ethers such as methyl cellosolve, butyl cellosolve, methyl carbitol, butyl carbitol, propylene glycol monomethyl ether, dipropylene glycol monoethyl ether, dipropylene glycol diethyl ether, and triethylene glycol monoethyl ether; esters such as ethyl acetate, butyl acetate, butyl cellosolve acetate, and carbitol acetate; aliphatic hydrocarbons such as octane and decane; and petroleum solvents such as petroleum ether, petroleum naphtha, hydrogenated petroleum naphtha, and solvent naphtha. The organic solvent may be used alone or in combination of two or more.

[0043] For the reaction between the component (a1) and the component (a2), it is preferable to use a catalyst for promoting the reaction. Examples of the catalyst include amine catalysts such as triethylamine and benzylmethylamine; quaternary ammonium salt catalysts such as methyltriethylammonium chloride, benzyltrimethylammonium chloride, benzyltrimethylammonium bromide, and benzyltrimethylammonium iodide; and phosphine catalysts such as triphenylphosphine. Among these, phosphine catalysts are preferable, and triphenylphosphine is more preferable. The catalyst may be used alone or in combination of two or more. When using a catalyst, the amount thereof is preferably 0.01 to 10 parts by mass, more preferably 0.05 to 5 parts by mass, and still more preferably 0.1 to 2 parts by mass with respect to 100 parts by mass in total of the component (a1) and the component (a2) from the viewpoint of obtaining an appropriate reaction rate.

[0044] For the reaction between the component (a1) and the component (a2), it is preferable to use a polymerization inhibitor for the purpose of preventing polymerization during the reaction. Examples of the polymerization inhibitor include hydroquinone, methylhydroquinone, hydroquinone monomethyl ether, catechol, and pyrogallol. The polymerization inhibitor may be used alone or in combination of two or more. When using a coincidence inhibitor, the amount used is preferably 0.01 to 1 part by mass, more preferably 0.02 to 0.8 part by mass, and still more preferably 0.1 to 0.5 part by mass with respect to 100 parts by mass in total of the (a1) component and the (a2) component.

[0045] From the viewpoint of allowing the reaction to proceed homogeneously while obtaining sufficient reactivity, the reaction temperature of the (a1) component and the (a2) component is preferably 60 to 150 °C, more preferably 80 to 120 °C, and still more preferably 90 to 110 °C.

[0046] Thus, the (A') component formed by reacting the (a1) component and the (a2) component has a hydroxyl group formed by a ring-opening addition reaction between the epoxy group of the (a1) component and the carboxyl group of the (a2) component. Next, by further reacting the (A') component with the (a3) component, an acid-modified vinyl group-containing epoxy resin in which the hydroxyl group of the (A') component (including the hydroxyl group originally present in the (a1) component) and the acid anhydride group of the (a3) component are semi-esterified can be obtained.

[0047] ((a3) polybasic acid anhydride) The (a3) component may contain a saturated group or an unsaturated group. Examples of the (a3) component include succinic anhydride, maleic anhydride, tetrahydrophthalic anhydride, phthalic anhydride, methyltetrahydrophthalic anhydride, ethyltetrahydrophthalic anhydride, hexahydrophthalic anhydride, methylhexahydrophthalic anhydride, ethylhexahydrophthalic anhydride, itaconic anhydride, and the like. Among these, tetrahydrophthalic anhydride is preferred from the viewpoint of the resolution of vias. The (a3) component may be used alone or in combination of two or more.

[0048] In the reaction between the (A') component and the (a3) component, for example, the acid value of the acid-modified vinyl group-containing epoxy resin can be adjusted by reacting 0.1 to 1.0 equivalents of the (a3) component with respect to 1 equivalent of the hydroxyl group in the (A') component.

[0049] The reaction temperature of the component (A’) and the component (a3) is preferably 50 to 150 °C, more preferably 60 to 120 °C, and even more preferably 70 to 100 °C from the viewpoint of allowing the reaction to proceed homogeneously while obtaining sufficient reactivity.

[0050] The content of the component (A) in the photosensitive resin composition of the present embodiment is not particularly limited, but from the viewpoints of heat resistance, dielectric properties, and chemical resistance, it is preferably 10 to 80% by mass, more preferably 20 to 60% by mass, and even more preferably 30 to 50% by mass based on the total amount of the resin components of the photosensitive resin composition.

[0051] <(B) epoxy resin> The photosensitive resin composition of the present embodiment contains an epoxy resin as the component (B). By containing the (B) epoxy resin, the photosensitive resin composition of the present embodiment can obtain excellent heat resistance in addition to improving the adhesiveness to electroless copper and the insulation reliability. As the (B) epoxy resin, one type may be used alone, or two or more types may be used in combination.

[0052] The (B) epoxy resin is preferably an epoxy resin having two or more epoxy groups. Epoxy resins are classified into glycidyl ether type epoxy resins, glycidyl amine type epoxy resins, glycidyl ester type epoxy resins, etc. Among these, glycidyl ether type epoxy resins are preferred.

[0053] The (B) epoxy resin can be classified into various epoxy resins according to the difference in the main skeleton. For example, it can be classified into bisphenol type epoxy resins, novolak type epoxy resins, aralkyl type epoxy resins, epoxy resins having an alicyclic skeleton, and other epoxy resins. Examples of the bisphenol type epoxy resin include bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol S type epoxy resin, 3,3’,5,5’-tetramethyl-4,4’-diglycidyloxydiphenylmethane, and the like. Examples of novolak type epoxy resins include bisphenol novolak type epoxy resins such as bisphenol A novolak type epoxy resin, bisphenol F novolak type epoxy resin, and bisphenol S novolak type epoxy resin; phenol novolak type epoxy resin, cresol novolak type epoxy resin, biphenyl novolak type epoxy resin, naphthol novolak type epoxy resin, and the like. Examples of aralkyl type epoxy resins include phenol aralkyl type epoxy resin, biphenyl aralkyl type epoxy resin, naphthol aralkyl type epoxy resin, and the like. Examples of epoxy resins having an alicyclic skeleton include dicyclopentadiene type epoxy resin and the like. Examples of other epoxy resins include stilbene type epoxy resin, naphthalene type epoxy resin, naphthylene ether type epoxy resin, biphenyl type epoxy resin, dihydroanthracene type epoxy resin, cyclohexanedimethanol type epoxy resin, trimethylol type epoxy resin, alicyclic epoxy resin, aliphatic chain epoxy resin, heterocyclic epoxy resin, spiro ring-containing epoxy resin, rubber-modified epoxy resin, and the like.

[0054] Among these, as the (B) epoxy resin, from the viewpoints of insulation reliability, dielectric properties, heat resistance, and adhesiveness to plated copper, bisphenol type epoxy resin, novolak type epoxy resin, and aralkyl type epoxy resin are preferable, and 3,3',5,5'-tetramethyl-4,4'-diglycidyloxydiphenylmethane, naphthol novolak type epoxy resin, and biphenyl aralkyl type epoxy resin are more preferable. (B) epoxy resin preferably uses a bisphenol type epoxy resin in combination with a novolak type epoxy resin or an aralkyl type epoxy resin from the viewpoints of insulation reliability, dielectric properties, heat resistance, and adhesiveness to plated copper, more preferably contains a bisphenol type epoxy resin and an aralkyl type epoxy resin, and even more preferably contains 3,3',5,5'-tetramethyl-4,4'-diglycidyloxydiphenylmethane and biphenyl aralkyl type epoxy resin. (B) When containing a bisphenol type epoxy resin and a novolak type epoxy resin or an aralkyl type epoxy resin as the epoxy resin, the content ratio of the two [bisphenol type epoxy resin / novolak type epoxy resin or aralkyl type epoxy resin] is not particularly limited, but is preferably 1.0 to 4.0, more preferably 1.5 to 3.0, still more preferably 2.0 to 2.5.

[0055] The equivalent ratio of the acidic substituent of component (A) to the epoxy group of component (B) [epoxy group / acidic substituent] in the photosensitive resin composition of the present embodiment is not particularly limited, but from the viewpoints of insulation reliability, dielectric properties, heat resistance, and adhesion to electroless copper, it is preferably 0.6 to 6.0, more preferably 0.7 to 4.0, still more preferably 0.8 to 2.0, and particularly preferably 0.9 to 1.2.

[0056] The content of component (B) in the photosensitive resin composition of the present embodiment is not particularly limited, but from the viewpoints of insulation reliability, dielectric properties, heat resistance, and adhesion to electroless copper, based on the total amount of the resin components of the photosensitive resin composition, it is preferably 1 to 50% by mass, more preferably 5 to 30% by mass, still more preferably 10 to 20% by mass.

[0057] <(C) Active ester compound> The photosensitive resin composition of the present embodiment contains an active ester compound as component (C). By containing the (C) active ester compound, the photosensitive resin composition of the present embodiment can lower the dielectric loss tangent while maintaining various properties well. Examples of the (C) active ester compound include those having a highly reactive ester group such as a phenol ester compound, a thiophenol ester compound, an N-hydroxyamine ester compound, and an ester compound of a heterocyclic hydroxy compound. These (C) active ester compounds may be linear or highly branched. Moreover, the (C) active ester compound is preferably a compound having two or more ester groups in one molecule. (C) The active ester compound may be used alone or in combination of two or more.

[0058] (C) The active ester compound is a compound having two or more active ester groups in one molecule, and the two or more active ester groups are preferably those formed from (c1) a polyvalent carboxylic acid compound and (c2) a compound having a phenolic hydroxyl group. The active ester group formed from (c1) a polyvalent carboxylic acid compound and (c2) a compound having a phenolic hydroxyl group is an ester bond formed by an esterification reaction (condensation reaction) between the carboxy group of the (c1) polyvalent carboxylic acid compound and the phenolic hydroxyl group of the (c2) compound having a phenolic hydroxyl group.

[0059] Examples of the (c1) polyvalent carboxylic acid compound include compounds having two or more aliphatic carboxy groups, compounds having two or more aromatic carboxy groups, and the like. Examples of the compound having two or more aliphatic carboxy groups include succinic acid, maleic acid, itaconic acid, and the like. Examples of the compound having two or more aromatic carboxy groups include benzenedicarboxylic acids such as phthalic acid, isophthalic acid, terephthalic acid; benzenetricarboxylic acids such as trimesic acid; benzene tetracarboxylic acids such as pyromellitic acid, and the like. Among these, from the viewpoints of heat resistance and dielectric properties, compounds having two or more aromatic carboxy groups are preferred, and benzenedicarboxylic acids are more preferred. (c1) The polyvalent carboxylic acid compound may be used alone or in combination of two or more.

[0060] Examples of the (c2) compound having a phenolic hydroxyl group include compounds having one, two, or three or more phenolic hydroxyl groups. Examples of the compound having one phenolic hydroxyl group include monophenols such as phenol, o-cresol, m-cresol, p-cresol; mononaphthols such as α-naphthol, β-naphthol; hydroxybenzophenone, etc. Examples of the compound having two phenolic hydroxyl groups include dihydroxybenzenes such as hydroquinone, resorcin, catechol; bisphenols such as bisphenol A, bisphenol F, bisphenol S, methylated bisphenol A, methylated bisphenol F, methylated bisphenol S; dihydroxynaphthalenes such as 1,5-dihydroxynaphthalene, 1,6-dihydroxynaphthalene, 2,6-dihydroxynaphthalene; phenolphthalein, dicyclopentadiene type phenol resin having two phenolic hydroxyl groups, etc. Examples of the compound having three or more phenolic hydroxyl groups include trihydroxybenzophenone, benzenetriol, tetrahydroxybenzophenone, phenol novolak resin, phenol aralkyl resin, etc. Among these, from the viewpoints of heat resistance and dielectric properties, the compound having one phenolic hydroxyl group and the compound having two phenolic hydroxyl groups are preferable, and monophenols, mononaphthols, bisphenols, and dicyclopentadiene type phenol resin having two phenolic hydroxyl groups are preferable. (c2) The compound having a phenolic hydroxyl group may be used alone or in combination of two or more.

[0061] The monophenols may be represented by the following general formula (C-1), the mononaphthols may be represented by the following general formula (C-2), the bisphenols may be represented by the following general formula (C-3), and the dicyclopentadiene type phenol resin having two phenolic hydroxyl groups may be represented by the following general formula (C-4).

[0062] [Chemical formula] (In the formula, R C1 ~R C4each independently represents a monovalent organic group. X C1 represents a divalent organic group. p1 represents an integer of 0 to 5, p2 represents an integer of 0 to 7, and p3 and p4 each independently represent an integer of 0 to 4.)

[0063] In the above general formulas (C-1) to (C-4), R C1 ~R C4 Examples of the monovalent organic group represented by include a monovalent aliphatic hydrocarbon group such as an alkyl group having 1 to 10 carbon atoms, an alkenyl group having 2 to 10 carbon atoms, and an alkynyl group having 2 to 10 carbon atoms; and a monovalent aromatic hydrocarbon group having 6 to 12 carbon atoms. The aliphatic hydrocarbon group and the aromatic hydrocarbon group may or may not have a substituent.) Examples of the divalent organic group represented by X in the above general formula (C-2) C2 include a divalent aliphatic hydrocarbon group such as an alkylene group having 1 to 10 carbon atoms, an alkylidene group having 2 to 10 carbon atoms, an alkenylene group having 2 to 10 carbon atoms, and an alkynylene group having 2 to 10 carbon atoms; and a divalent aromatic hydrocarbon group having 6 to 12 carbon atoms. The aliphatic hydrocarbon group and the aromatic hydrocarbon group may or may not have a substituent.)

[0064] (C) The active ester compound is preferably represented by the following general formula (C-5).

[0065] [Chemical formula] (In the formula, X represents the residue excluding the two carboxy groups of the above (c1) polyvalent carboxylic acid compound, Y represents the residue excluding the two phenolic hydroxyl groups of the compound having two phenolic hydroxyl groups as the compound having a phenolic hydroxyl group in the above (c2), Z represents the residue excluding one phenolic hydroxyl group of the compound having one phenolic hydroxyl group as the compound having a phenolic hydroxyl group in the above (c2), or the residue excluding one phenolic hydroxyl group of the compound having two phenolic hydroxyl groups, and p5 represents a number of 0 to 10.)

[0066] In the general formula (C-5) above, p5 is preferably a number from 0 to 5, more preferably a number from 0 to 4, and even more preferably a number from 0 to 3.

[0067] (C) The ester group equivalent of the active ester compound is not particularly limited, but from the viewpoints of heat resistance and dielectric properties, it is preferably 100 to 300 g / eq, more preferably 150 to 260 g / eq, and even more preferably 200 to 230 g / eq.

[0068] (C) The active ester compound can be produced by a known method. For example, it can be obtained by subjecting a (c1) polyvalent carboxylic acid compound and a (c2) compound having a phenolic hydroxyl group to a condensation reaction.

[0069] The equivalent ratio [active ester group / epoxy group] of the epoxy group of the (B) epoxy resin and the active ester group of the (C) active ester compound in the photosensitive resin composition of the present embodiment is preferably 0.01 to 0.4, more preferably 0.1 to 0.3, and even more preferably 0.15 to 0.25 from the viewpoints of heat resistance and dielectric properties. Further, the photosensitive resin composition of the present embodiment satisfies the preferred range of the equivalent ratio [epoxy group / acidic substituent] of the acidic substituent of the (A) component and the epoxy group of the (B) component in the photosensitive resin composition of the present embodiment, and preferably satisfies the preferred range of the equivalent ratio [active ester group / epoxy group] of the epoxy group of the (B) epoxy resin and the active ester group of the (C) active ester compound in the photosensitive resin composition of the present embodiment.

[0070] The content of the (C) active ester compound in the photosensitive resin composition of the present embodiment is not particularly limited, but from the viewpoints of heat resistance and dielectric properties, based on the total amount of the resin components of the photosensitive resin composition, it is preferably 1 to 15% by mass, more preferably 2 to 10% by mass, and even more preferably 3 to 6% by mass.

[0071] <(D) Crosslinking Agent> The photosensitive resin composition of the present embodiment preferably further contains, as component (D), a crosslinking agent having two or more ethylenically unsaturated groups and no acidic substituent [hereinafter sometimes simply referred to as the (D) crosslinking agent]. The (D) crosslinking agent reacts with the ethylenically unsaturated groups of component (A) to increase the crosslinking density of the cured product. Therefore, by containing the (D) crosslinking agent, the photosensitive resin composition of the present embodiment tends to have better heat resistance and dielectric properties. The (D) crosslinking agent may be used alone or in combination of two or more.

[0072] Examples of the (D) crosslinking agent include bifunctional monomers having two ethylenically unsaturated groups and polyfunctional monomers having three or more ethylenically unsaturated groups. Examples of the ethylenically unsaturated groups of the (D) crosslinking agent are the same as those of the ethylenically unsaturated groups of component (A), and the preferred ones are also the same.

[0073] Examples of the bifunctional monomer include aliphatic di(meth)acrylates such as trimethylolpropane di(meth)acrylate, polypropylene glycol di(meth)acrylate, and polyethylene glycol di(meth)acrylate; di(meth)acrylates having an alicyclic skeleton such as tricyclodecane dimethanol diacrylate; and aromatic di(meth)acrylates such as 2,2-bis(4-(meth)acryloxypolyethoxypolypropoxyphenyl)propane and bisphenol A diglycidyl ether di(meth)acrylate. Among these, from the viewpoint of obtaining a lower dielectric tangent, di(meth)acrylates having an alicyclic skeleton are preferred, and tricyclodecane dimethanol diacrylate is more preferred.

[0074] Examples of the polyfunctional monomer include (meth)acrylate compounds having a skeleton derived from trimethylolpropane such as trimethylolpropane tri(meth)acrylate; (meth)acrylate compounds having a skeleton derived from tetramethylolmethane such as tetramethylolmethane tri(meth)acrylate and tetramethylolmethane tetra(meth)acrylate; (meth)acrylate compounds having a skeleton derived from pentaerythritol such as pentaerythritol tri(meth)acrylate and pentaerythritol tetra(meth)acrylate; (meth)acrylate compounds having a skeleton derived from dipentaerythritol such as dipentaerythritol penta(meth)acrylate and dipentaerythritol hexa(meth)acrylate; (meth)acrylate compounds having a skeleton derived from ditrimethylolpropane such as ditrimethylolpropane tetra(meth)acrylate; and (meth)acrylate compounds having a skeleton derived from diglycerin. Among these, from the viewpoint of improving chemical resistance after photocuring, (meth)acrylate compounds having a skeleton derived from dipentaerythritol are preferred, and dipentaerythritol penta(meth)acrylate is more preferred. Here, the "(meth)acrylate compound having a skeleton derived from XXX" (where XXX is a compound name) means an esterified product of XXX and (meth)acrylic acid, and the esterified product includes compounds modified with an alkyleneoxy group.

[0075] When the photosensitive resin composition of this embodiment contains (D) a crosslinking agent, the content of (D) the crosslinking agent is not particularly limited, but from the viewpoints of heat resistance and dielectric properties, it is preferably 5 to 70 parts by mass, more preferably 10 to 60 parts by mass, and still more preferably 25 to 55 parts by mass with respect to 100 parts by mass of component (A).

[0076] <(E) elastomer> The photosensitive resin composition of the present embodiment preferably further contains an elastomer as component (E). By containing the (E) elastomer in the photosensitive resin composition of the present embodiment, the adhesiveness to electrodeposited copper tends to be further improved. Further, the (E) elastomer can suppress the reduction in flexibility and adhesiveness to electrodeposited copper caused by the strain (internal stress) inside the cured product due to the curing shrinkage of the above component (A). As the (E) elastomer, one kind may be used alone, or two or more kinds may be used in combination.

[0077] The (E) elastomer may have a reactive functional group at the molecular terminal or in the molecular chain. Examples of the reactive functional group include an acid anhydride group, an epoxy group, a hydroxyl group, a carboxy group, an amino group, an amide group, an isocyanato group, an acrylic group, a methacrylic group, a vinyl group, etc. Among these, from the viewpoints of via resolution and adhesiveness to electrodeposited copper, an acid anhydride group, an epoxy group, a hydroxyl group, a carboxy group, an amino group, and an amide group are preferable, an acid anhydride group and an epoxy group are more preferable, and an acid anhydride group is even more preferable. Examples of the acid anhydride group preferably include acid anhydride groups derived from phthalic anhydride, maleic anhydride, trimellitic anhydride, pyromellitic anhydride, hexahydrophthalic anhydride, tetrahydrophthalic anhydride, methylnadic anhydride, nadic anhydride, glutaric anhydride, dimethylglutaric anhydride, diethylglutaric anhydride, succinic anhydride, methylhexahydrophthalic anhydride, methyltetrahydrophthalic anhydride, etc., and more preferably an acid anhydride group derived from maleic anhydride. When the (E) elastomer has an acid anhydride group, from the viewpoints of via resolution and dielectric properties, the number of acid anhydride groups in one molecule is preferably 1 to 10, more preferably 1 to 6, and even more preferably 2 to 5.

[0078] The photosensitive resin composition of the present embodiment preferably contains, as the (E) elastomer, an elastomer having an ethylenically unsaturated group and an acidic substituent. Examples of the acidic substituent and ethylenically unsaturated group include the same ones as those of the acidic substituent and ethylenically unsaturated group of component (A). Among these, the (E) elastomer preferably has an acid anhydride group as the acidic substituent as described above and a 1,2-vinyl group as the ethylenically unsaturated group, which will be described later.

[0079] Examples of the (E) elastomer include polybutadiene-based elastomers, polyester-based elastomers, styrene-based elastomers, olefin-based elastomers, urethane-based elastomers, polyamide-based elastomers, acrylic-based elastomers, silicone-based elastomers, and derivatives of these elastomers. Among these, from the viewpoint of improving the adhesion to plated copper and further improving the compatibility and solubility with the resin component, polybutadiene-based elastomers are preferred.

[0080] The polybutadiene-based elastomer preferably comprises a structure of a 1,4-trans form and a 1,4-cis form containing a 1,2-vinyl group. As described above, from the viewpoint of via resolution, the polybutadiene-based elastomer is preferably a polybutadiene-based elastomer having an acid anhydride group and modified with an acid anhydride, and more preferably a polybutadiene-based elastomer having an acid anhydride group derived from maleic anhydride. The polybutadiene-based elastomer is commercially available. Specific examples thereof include, for example, "POLYVEST (registered trademark) MA75", "POLYVEST (registered trademark) EP MA120" (both are product names manufactured by Evonik), "Ricon (registered trademark) 130MA8", "Ricon (registered trademark) 131MA5", "Ricon (registered trademark) 184MA6" (all are product names manufactured by Cray Valley), etc.

[0081] From the viewpoint of adhesion to plated copper, the polybutadiene-based elastomer may be a polybutadiene having an epoxy group [hereinafter, may be referred to as epoxidized polybutadiene.]. From the viewpoints of adhesiveness and flexibility with copper plating, the epoxidized polybutadiene is preferably an epoxidized polybutadiene represented by the following general formula (E-1).

[0082] [Chemical formula] (In the formula, a, b, and c each represent the ratio of the structural units in the parentheses. a is 0.05 to 0.40, b is 0.02 to 0.30, c is 0.30 to 0.80, and further, a + b + c = 1.00 and (a + c) > b are satisfied. y represents the number of structural units in the angular brackets and is an integer of 10 to 250.)

[0083] In the above general formula (E-1), the bonding order of each structural unit in the angular brackets is arbitrary. That is, the structural unit shown on the left, the structural unit shown in the center, and the structural unit shown on the right may be in an alternating order. When each is represented by (a), (b), and (c), respectively, -[(a)-(b)-(c)]-[(a)-(b)-(c)-]-, -[(a)-(c)-(b)]-[(a)-(c)-(b)-]-, -[(b)-(a)-(c)]-[(b)-(a)-(c)-]-, -[(a)-(b)-(c)]-[(c)-(b)-(a)-]-, -[(a)-(b)-(a)]-[(c)-(b)-(c)-]-, -[(c)-(b)-(c)]-[(b)-(a)-(a)-]-, etc., various bonding orders are possible. From the viewpoints of adhesiveness and flexibility with copper plating, a is preferably 0.10 to 0.30, b is preferably 0.10 to 0.30, and c is preferably 0.40 to 0.80. Also, from the same viewpoints, y is preferably an integer of 30 to 180. In the above general formula (E-1), commercially available products of epoxidized polybutadiene with a = 0.20, b = 0.20, c = 0.60, and y being an integer of 10 to 250 include "Epolead (registered trademark) PB3600" (manufactured by Daicel Corporation), etc.

[0084] Examples of the polyester-based elastomer include those obtained by polycondensing a dicarboxylic acid or its derivative and a diol compound or its derivative. Examples of the dicarboxylic acid include aromatic dicarboxylic acids such as terephthalic acid, isophthalic acid, and naphthalenedicarboxylic acid, and aromatic dicarboxylic acids in which the hydrogen atoms of these aromatic nuclei are substituted with a methyl group, an ethyl group, a phenyl group, etc.; aliphatic dicarboxylic acids having 2 to 20 carbon atoms such as adipic acid, sebacic acid, and dodecanedicarboxylic acid; alicyclic dicarboxylic acids such as cyclohexanedicarboxylic acid, etc. Examples of the diol compound include aliphatic diols such as ethylene glycol, 1,3-propanediol, 1,4-butanediol, 1,6-hexanediol, and 1,10-decanediol; alicyclic diols such as 1,4-cyclohexanediol; aromatic diols such as bisphenol A, bis(4-hydroxyphenyl)methane, bis(4-hydroxy-3-methylphenyl)propane, and resorcinol, etc. In addition, as the polyester-based elastomer, a multi-block copolymer in which an aromatic polyester (for example, polybutylene terephthalate) part is a hard segment component and an aliphatic polyester (for example, polytetramethylene glycol) part is a soft segment component is preferably mentioned. The multi-block copolymer has various grades depending on the types, ratios, and molecular weight differences of the hard segment and the soft segment. Specific examples thereof include "Hytrel (registered trademark)" (manufactured by DuPont - Toray Co., Ltd.), "Pelprene (registered trademark)" (manufactured by Toyobo Co., Ltd.), "Esper (registered trademark)" (manufactured by Hitachi Chemical Co., Ltd.), etc.

[0085] When the photosensitive resin composition of the present embodiment contains (E) an elastomer, the content of (E) the elastomer is not particularly limited, but from the viewpoints of heat resistance and adhesiveness to electroless copper, based on the total amount of the resin components of the photosensitive resin composition, it is preferably 1 to 15% by mass, more preferably 2 to 10% by mass, and still more preferably 3 to 7% by mass.

[0086] <(F) Photoinitiator> The photosensitive resin composition of this embodiment preferably further contains a photoinitiator as component (F). By containing the (F) photoinitiator, the photosensitive resin composition of this embodiment tends to have better resolution of vias. (F) The photoinitiator may be used alone or in combination of two or more.

[0087] (F) The photoinitiator is not particularly limited as long as it can photopolymerize an ethylenically unsaturated group, and can be appropriately selected from commonly used photoinitiators. (F) Examples of the photoinitiator include benzoins such as benzoin, benzoin methyl ether, and benzoin isopropyl ether; acetophenones such as acetophenone, 2,2-dimethoxy-2-phenylacetophenone, 2,2-diethoxy-2-phenylacetophenone, 1,1-dichloroacetophenone, 1-hydroxycyclohexyl phenyl ketone, 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)-1-butanone, 2-methyl-1-[4-(methylthio)phenyl]-2-morpholino-1-propanone, and N,N-dimethylaminoacetophenone; anthraquinones such as 2-methylanthraquinone, 2-ethylanthraquinone, 2-tert-butylanthraquinone, 1-chloroanthraquinone, 2-amylanthraquinone, and 2-aminoanthraquinone; thioxanthones such as 2,4-dimethylthioxanthone, 2,4-diethylthioxanthone, 2-chlorothioxanthone, and 2,4-diisopropylthioxanthone; ketals such as acetophenone dimethyl ketal and benzyl dimethyl ketal; benzophenones such as benzophenone, methylbenzophenone, 4,4'-dichlorobenzophenone, 4,4'-bis(diethylamino)benzophenone, Michler's ketone, and 4-benzoyl-4'-methyldiphenyl sulfide; acridines such as 9-phenylacridine and 1,7-bis(9,9'-acridinyl)heptane; acylphosphine oxides such as 2,4,6-trimethylbenzoyl diphenylphosphine oxide; oxime esters such as 1,2-octanedione-1-[4-(phenylthio)phenyl]-2-(O-benzoyloxime), 1-[9-ethyl-6-(2-methylbenzoyl)-9H-carbazol-3-yl]ethanone 1-(O-acetyl oxime), and 1-phenyl-1,2-propanedione-2-[O-(ethoxycarbonyl)oxime].

[0088] Among these, acetophenones and thioxanthones are preferred, and 2-methyl-1-[4-(methylthio)phenyl]-2-morpholino-1-propanone and 2,4-diethylthioxanthone are more preferred. Acetophenones have the advantage of being less volatile and less likely to be generated as outgas, and thioxanthones have the advantage of being capable of photocuring in the visible light region. It is more preferable to use acetophenones and thioxanthones in combination, and it is particularly preferable to use 2-methyl-1-[4-(methylthio)phenyl]-2-morpholino-1-propanone and 2,4-diethylthioxanthone in combination.

[0089] When the photosensitive resin composition of the present embodiment contains the (F) photoinitiator, the content of the (F) photoinitiator is not particularly limited, but based on the total amount of the resin components of the photosensitive resin composition, it is preferably 0.01 to 20% by mass, more preferably 0.1 to 10% by mass, still more preferably 0.2 to 5% by mass, and particularly preferably 0.3 to 2% by mass. When the content of the (F) photoinitiator is at least the above lower limit value, the exposed portion tends to be reduced in elution during development, and when it is at most the above upper limit value, the heat resistance tends to be improved.

[0090] <(G) Inorganic filler> The photosensitive resin composition of the present embodiment preferably further contains an inorganic filler as the (G) component. By containing the (G) inorganic filler, the photosensitive resin composition of the present embodiment tends to obtain a lower dielectric tangent and excellent low thermal expansibility. (G) The inorganic filler may be used alone or in combination of two or more.

[0091] (G) Examples of the inorganic filler include silica (SiO 2 ), alumina (Al 2 O 3 ), titania (TiO 2 ), tantalum oxide (Ta 2 O 5 ), zirconia (ZrO 2 ), silicon nitride (Si 3 N 4) Barium titanate (BaO·TiO 2 ) Barium carbonate (BaCO 3 ) Magnesium carbonate (MgCO 3 ) Aluminum hydroxide (Al(OH) 3 ) Magnesium hydroxide (Mg(OH) 2 ) Lead titanate (PbO·TiO 2 ) Lead zirconate titanate (PZT), Lead lanthanum zirconate titanate (PLZT), Gallium oxide (Ga 2 O 3 ) Spinel (MgO·Al 2 O 3 ) Mullite (3Al 2 O 3 ·2SiO 2 ) Cordierite (2MgO·2Al 2 O 3 / 5SiO 2 ) Talc (3MgO·4SiO 2 ·H 2 O), Aluminum titanate (TiO 2 ·Al 2 O 3 ), Yttria-containing zirconia (Y 2 O 3 ·ZrO 2 ), Barium silicate (BaO·8SiO 2 ), Boron nitride (BN), Calcium carbonate (CaCO 3 ), Barium sulfate (BaSO 4 ), Calcium sulfate (CaSO 4 ), Zinc oxide (ZnO), Magnesium titanate (MgO·TiO 2 ), Hydrotalcite, mica, calcined kaolin, carbon (C), etc. may be mentioned. Among these, silica is preferable from the viewpoints of heat resistance, low thermal expansion property, and dielectric property.

[0092] (G) The inorganic filler may be surface-treated with a coupling agent such as a silane coupling agent from the viewpoint of improving the dispersibility in the photosensitive resin composition. Examples of the silane coupling agent include amino silane-based coupling agents, epoxy silane-based coupling agents, phenyl silane-based coupling agents, alkyl silane-based coupling agents, alkenyl silane-based coupling agents, alkynyl silane-based coupling agents, haloalkyl silane-based coupling agents, siloxane-based coupling agents, hydrosilane-based coupling agents, silazane-based coupling agents, alkoxysilane-based coupling agents, chlorosilane-based coupling agents, (meth)acrylic silane-based coupling agents, isocyanurate silane-based coupling agents, ureido silane-based coupling agents, mercapto silane-based coupling agents, sulfide silane-based coupling agents, isocyanate silane-based coupling agents, and the like.

[0093] (G) As the inorganic filler, only the inorganic filler surface-treated with one kind of coupling agent may be used, or two or more kinds of inorganic fillers surface-treated with different coupling agents may be used in combination. When using a coupling agent, the addition method may be the so-called integral blend treatment method in which the coupling agent is added after blending the (G) inorganic filler in the photosensitive resin composition, or may be a method in which the (G) inorganic filler before blending is surface-treated with the coupling agent in a dry or wet manner in advance.

[0094] (G) From the viewpoint of the resolution of vias, the average particle size of the inorganic filler is preferably 0.01 to 5 μm, more preferably 0.05 to 3 μm, still more preferably 0.1 to 1 μm, and particularly preferably 0.15 to 0.7 μm. (G) As the inorganic filler, two or more kinds of inorganic fillers having different average particle sizes may be used in combination. (G) The average particle diameter of the inorganic filler means the volume average particle diameter. Using a submicron particle analyzer (manufactured by Beckman Coulter, Inc., trade name: N5), in accordance with the international standard ISO13321, with a refractive index of 1.38, the particles dispersed in the solvent are measured, and it can be determined as the particle diameter corresponding to the integrated value of 50% (volume basis) in the particle size distribution.

[0095] When the photosensitive resin composition of this embodiment contains the (G) inorganic filler, its content is not particularly limited, but based on the total solid content of the photosensitive resin composition, it is preferably 10 to 80% by mass, more preferably 20 to 65% by mass, still more preferably 30 to 55% by mass, and particularly preferably 40 to 50% by mass. When the content of the (G) inorganic filler is at least the above lower limit value, a lower dielectric tangent and coefficient of thermal expansion tend to be obtained, and when it is at most the above upper limit value, better adhesion to electroless copper and resolution of vias tend to be obtained.

[0096] <(H) Curing accelerator> The photosensitive resin composition of this embodiment preferably further contains a curing accelerator as the (H) component. By containing the (H) curing accelerator, the heat resistance, dielectric properties, etc. of the resulting cured product tend to be further improved. (H) The curing accelerator may be used alone or in combination of two or more.

[0097] (H) As the curing accelerator, for example, imidazole and its derivatives such as 2-methylimidazole, 2-ethyl-4-methylimidazole, 1-benzyl-2-methylimidazole, 2-phenylimidazole, 2-phenyl-4-methyl-5-hydroxymethylimidazole, isocyanate masked imidazole (addition reaction product of hexamethylene diisocyanate resin and 2-ethyl-4-methylimidazole); tertiary amines such as trimethylamine, N,N-dimethyloctylamine, N-benzyldimethylamine, pyridine, N-methylmorpholine, hexa(N-methyl)melamine, 2,4,6-tris(dimethylaminophenol), tetramethylguanidine, m-aminophenol; organic phosphines such as tributylphosphine, triphenylphosphine, tris-2-cyanoethylphosphine; phosphonium salts such as tri-n-butyl(2,5-dihydroxyphenyl)phosphonium bromide, hexadecyltributylphosphonium chloride; quaternary ammonium salts such as benzyltrimethylammonium chloride, phenyltributylammonium chloride; the above polybasic acid anhydrides; diphenyliodonium tetrafluoroborate, triphenylsulfonium hexafluoroantimonate, 2,4,6-triphenylthiopyrylium hexafluorophosphate, etc. can be mentioned. Among these, from the viewpoint of obtaining an excellent curing effect, imidazole and imidazole derivatives are preferable.

[0098] When the photosensitive resin composition of this embodiment contains the (H) curing accelerator, its content is not particularly limited, but from the viewpoint of further improving heat resistance and dielectric properties, it is preferably 0.01 to 10% by mass, more preferably 0.05 to 5% by mass, and still more preferably 0.1 to 1% by mass.

[0099] <(I) Epoxy resin curing agent> The photosensitive resin composition of this embodiment preferably further contains an epoxy resin curing agent as the (I) component. By containing the (H) epoxy resin curing agent, the heat resistance, dielectric properties, etc. of the obtained cured product tend to be further improved. (I) The epoxy resin curing agent may be used alone or in combination of two or more.

[0100] (I) Examples of the epoxy resin curing agent include guanamines such as acetoguanamine and benzoguanamine; polyamines such as diaminodiphenylmethane, m-phenylenediamine, m-xylenediamine, diaminodiphenylsulfone, dicyandiamide, urea, urea derivatives, melamine, and polybasic hydrazide; organic acid salts and / or epoxy adducts thereof; amine complexes of boron trifluoride; triazine derivatives such as ethyldiamino-S-triazine, 2,4-diamino-S-triazine, and 2,4-diamino-6-xylyl-S-triazine; and polyphenols such as polyvinylphenol, brominated polyvinylphenol, phenol novolak, alkylphenol novolak, and phenol novolak resin containing a triazine ring.

[0101] When the photosensitive resin composition of this embodiment contains (I) an epoxy resin curing agent, its content is not particularly limited, but from the viewpoint of further improving heat resistance and dielectric properties, based on the total amount of the resin components of the photosensitive resin composition, it is preferably 0.01 to 10% by mass, more preferably 0.05 to 5% by mass, and still more preferably 0.1 to 1% by mass.

[0102] <(J) Additives> The photosensitive resin composition of this embodiment may contain, if necessary, pigments such as phthalocyanine blue, phthalocyanine green, iodine green, diazo yellow, crystal violet, titanium oxide, carbon black, and naphthalene black; adhesion aids such as melamine; sensitizers such as 4,4'-bisdiethylaminobenzophenone; antifoaming agents such as silicone compounds; and various known and commonly used additives such as polymerization inhibitors, thickeners, and flame retardants. The content of these (J) additives may be appropriately adjusted according to each purpose, but for each of them, based on the total amount of the resin components of the photosensitive resin composition, it is preferably 0.01 to 5% by mass, more preferably 0.05 to 3% by mass, and still more preferably 0.1 to 1% by mass.

[0103] <Diluent> In the photosensitive resin composition of this embodiment, a diluent can be used as necessary. As the diluent, for example, organic solvents and the like can be used. Examples of the organic solvent include ketones such as methyl ethyl ketone and cyclohexanone; aromatic hydrocarbons such as toluene, xylene, and tetramethylbenzene; glycol ethers such as methyl cellosolve, butyl cellosolve, methyl carbitol, butyl carbitol, propylene glycol monomethyl ether, dipropylene glycol monoethyl ether, dipropylene glycol diethyl ether, and triethylene glycol monoethyl ether; esters such as ethyl acetate, butyl acetate, propylene glycol monoethyl ether acetate, butyl cellosolve acetate, and carbitol acetate; aliphatic hydrocarbons such as octane and decane; petroleum solvents such as petroleum ether, petroleum naphtha, hydrogenated petroleum naphtha, and solvent naphtha. The diluent may be used alone or in combination of two or more.

[0104] The content of the diluent may be appropriately selected so that the concentration of the total solid content in the photosensitive resin composition is preferably 30 to 90% by mass, more preferably 40 to 80% by mass, and still more preferably 50 to 70% by mass. By adjusting the amount of the diluent used within the above range, the coatability of the photosensitive resin composition is improved, and the formation of a higher definition pattern becomes possible.

[0105] The photosensitive resin composition of this embodiment can be obtained by kneading and mixing each component with a roll mill, a bead mill, or the like. Here, the photosensitive resin composition of this embodiment may be used in a liquid state or in a film state. When used in a liquid state, the coating method of the photosensitive resin composition of this embodiment is not particularly limited, and examples thereof include various coating methods such as a printing method, a spin coating method, a spray coating method, a jet dispensing method, an inkjet method, and a dipping coating method. Among these, from the viewpoint of more easily forming a photosensitive layer, the printing method and the spin coating method are preferred. When used in the form of a film, for example, it can be used in the form of a photosensitive resin film described later. In this case, a photosensitive layer with a desired thickness can be formed by laminating it on a carrier film using a laminator or the like. Note that using it in the form of a film is preferable because it improves the manufacturing efficiency of multilayer printed wiring boards.

[0106] [Photosensitive Resin Film] The photosensitive resin film of this embodiment is composed of the photosensitive resin composition of this embodiment and is suitable for use in forming a photosensitive layer that will later become an interlayer insulating layer. The photosensitive resin film of this embodiment may be provided on a carrier film. The thickness (thickness after drying) of the photosensitive resin film (photosensitive layer) is not particularly limited, but from the perspective of thinning multilayer printed wiring boards, it is preferably 1 to 100 μm, more preferably 3 to 50 μm, and even more preferably 5 to 40 μm.

[0107] The photosensitive resin film of this embodiment can be formed, for example, by applying and drying the photosensitive resin composition of this embodiment on a carrier film using a known coating device such as a comma coater, bar coater, kiss coater, roll coater, gravure coater, or die coater. Examples of the carrier film include polyesters such as polyethylene terephthalate and polybutylene terephthalate; polyolefins such as polypropylene and polyethylene. The thickness of the carrier film is preferably 5 to 100 μm, more preferably 10 to 60 μm, and even more preferably 15 to 45 μm.

[0108] Also, a protective film can be provided on the surface of the photosensitive resin film of this embodiment opposite to the surface in contact with the carrier film. As the protective film, for example, polymer films such as polyethylene and polypropylene can be used. Also, a polymer film similar to the above-described carrier film may be used, or a different polymer film may be used.

[0109] For drying the coating film formed by applying the photosensitive resin composition, a dryer using hot air drying, far-infrared rays, or near-infrared rays can be used. As the drying temperature, it is preferably 60 to 150°C, more preferably 70 to 120°C, and even more preferably 80 to 100°C. Also, as the drying time, it is preferably 1 to 60 minutes, more preferably 2 to 30 minutes, and even more preferably 5 to 20 minutes. From the viewpoint of avoiding the diffusion of the diluent in the manufacturing process of the multilayer printed wiring board, the content of the residual diluent in the photosensitive resin film after drying is preferably 3% by mass or less, more preferably 2% by mass or less, and even more preferably 1% by mass or less.

[0110] The photosensitive resin film of this embodiment is excellent in via resolution, adhesion to electrodeposited copper, and insulation reliability, and thus is suitable as an interlayer insulating layer of a multilayer printed wiring board. That is, the present invention also provides a photosensitive resin film for an interlayer insulating layer comprising the photosensitive resin composition of this embodiment.

[0111] [Multilayer Printed Wiring Board and Method for Manufacturing the Same] The multilayer printed wiring board of this embodiment contains an interlayer insulating layer formed using the above-described photosensitive resin composition or the photosensitive resin film of this embodiment. The manufacturing method of the multilayer printed wiring board of this embodiment is not particularly limited as long as it has a step of forming an interlayer insulating layer using the photosensitive resin composition of this embodiment, and for example, it can be easily manufactured by the following manufacturing method of the multilayer printed wiring board of this embodiment.

[0112] A method for manufacturing a multilayer printed wiring board using the photosensitive resin film of this embodiment will be described with appropriate reference to FIG. 1. The multilayer printed wiring board 100A can be manufactured, for example, by a manufacturing method including the following steps (1) to (4). Step (1): A step of laminating the photosensitive resin film of this embodiment on one or both sides of a circuit board [hereinafter referred to as lamination step (1)]. Step (2): A step of forming an interlayer insulating layer having vias by exposing and developing the photosensitive resin film laminated in Step (1) [hereinafter referred to as the photo via forming step (2)]. Step (3): A step of roughening the vias and the interlayer insulating layer [hereinafter referred to as the roughening step (3)]. Step (4): A step of forming a circuit pattern on the interlayer insulating layer [hereinafter referred to as the circuit pattern forming step (4)].

[0113] (Lamination step (1)) The lamination step (1) is a step of laminating the photosensitive resin film (photosensitive resin film for interlayer insulating layer) of the present embodiment on one or both sides of a circuit board (substrate 101 having a circuit pattern 102) using a vacuum laminator. Examples of the vacuum laminator include a vacuum applicator manufactured by Nichigo-Morton Co., Ltd., a vacuum pressure type laminator manufactured by Meiki Seisakusho Co., Ltd., a roll type dry coater manufactured by Hitachi, Ltd., and a vacuum laminator manufactured by Hitachi Chemical Electronics Co., Ltd.

[0114] When a protective film is provided on the photosensitive resin film, after peeling or removing the protective film, it can be laminated by pressure-bonding to the circuit board while applying pressure and heat so that the photosensitive resin film is in contact with the circuit board. The lamination can be carried out, for example, after preheating the photosensitive resin film and the circuit board as necessary, under reduced pressure with a pressure-bonding temperature of 70 to 130°C, a pressure-bonding pressure of 0.1 to 1.0 MPa, and an air pressure of 20 mmHg (26.7 hPa) or less, but is not particularly limited to these conditions. Also, the lamination method may be a batch type or a continuous type using a roll. Finally, the photosensitive resin film laminated on the circuit board is cooled to near room temperature to obtain an interlayer insulating layer 103. When the photosensitive resin film has a carrier film, the carrier film may be peeled off here or may be peeled off after exposure as described later.

[0115] (Photo via formation step (2)) In the photo via formation step (2), at least a part of the photosensitive resin film laminated on the circuit board is exposed and then developed. By exposure, the portion irradiated with actinic rays is photocured to form a pattern. There is no particular limitation on the exposure method. For example, a method of irradiating actinic rays in an image shape through a negative or positive mask pattern called an artwork (mask exposure method) may be employed, or a method of irradiating actinic rays in an image shape by a direct drawing exposure method such as an LDI (Laser Direct Imaging) exposure method or a DLP (Digital Light Processing) exposure method may be employed. As the light source of the actinic rays, known light sources can be used. Specifically, examples of the light source include gas lasers such as carbon arc lamps, mercury vapor arc lamps, high-pressure mercury lamps, xenon lamps, and argon lasers; solid lasers such as YAG lasers; and those that effectively emit ultraviolet rays or visible light such as semiconductor lasers. The exposure amount is appropriately selected depending on the light source used, the thickness of the photosensitive layer, etc. For example, in the case of ultraviolet irradiation from a high-pressure mercury lamp, when the thickness of the photosensitive layer is 1 to 100 μm, usually, 10 to 1,000 mJ / cm 2 is preferable, and 15 to 500 mJ / cm 2 is more preferable.

[0116] In development, the uncured portion of the photosensitive layer is removed from the substrate, whereby an interlayer insulating layer made of a photocured cured product is formed on the substrate. When a carrier film exists on the photosensitive layer, the carrier film is removed and then the unexposed portion is removed (developed). Development methods include wet development and dry development, and either may be employed. However, wet development is widely used, and wet development can also be employed in this embodiment. In the case of wet development, development is carried out by a known development method using a developer corresponding to the photosensitive resin composition. Examples of the development method include methods using a dip method, a paddle method, a spray method, brushing, slapping, scraping, rocking immersion, etc. Among these, from the viewpoint of improving resolution, the spray method is preferable, and among the spray methods, the high-pressure spray method is more preferable. Development may be carried out by one method, or may be carried out in combination of two or more methods. The composition of the developer is appropriately selected according to the composition of the photosensitive resin composition. Examples include an alkaline aqueous solution, an aqueous developer, an organic solvent-based developer, etc., and among these, an alkaline aqueous solution is preferable.

[0117] In the photovia formation step (2), after exposure and development, post-UV cure with an exposure amount of about 0.2 to 10 J / cm 2 (preferably 0.5 to 5 J / cm 2 ) and post-thermal cure at a temperature of about 60 to 250°C (preferably 120 to 200°C) may be carried out as necessary to further cure the interlayer insulating layer, and it is preferably done so. In the above manner, an interlayer insulating layer having vias 104 is formed. There is no particular limitation on the shape of the vias. Explaining in terms of the cross-sectional shape, for example, a square, an inverted trapezoid (the upper side is longer than the lower side), etc. can be mentioned. Explaining in terms of the shape seen from the front (the direction in which the via bottom can be seen), a circle, a square, etc. can be mentioned. In the formation of vias by the photolithography method in this embodiment, vias having a cross-sectional shape of an inverted trapezoid (the upper side is longer than the lower side) can be formed, and in this case, it is preferable because the wrap-around property to the via wall surface of the plated copper is high.

[0118] The size (diameter) of the vias formed by this step can be less than 40 μm, and further, it can also be 35 μm or less or 30 μm or less, and can be made smaller than the size of vias produced by laser processing. There is no particular limitation on the lower limit value of the size (diameter) of the vias formed by this step, but it may be 15 μm or more, or may be 20 μm or more. However, the size (diameter) of the vias formed by this process is not limited to less than 40 μm, and for example, it may be arbitrarily selected within the range of 15 to 300 μm.

[0119] (Roughening treatment step (3)) In the roughening treatment step (3), the surfaces of the vias and the interlayer insulating layer are roughened with a roughening solution. In addition, when smears occur in the above photo via formation step (2), the smears may be removed with the above roughening solution. The roughening treatment and the removal of smears can be performed simultaneously. Examples of the above roughening solution include a chromium / sulfuric acid roughening solution, an alkaline permanganic acid roughening solution (for example, a sodium permanganate roughening solution, etc.), and a sodium fluoride / chromium / sulfuric acid roughening solution. By the roughening treatment, anchor-like irregularities are formed on the surfaces of the vias and the interlayer insulating layer.

[0120] (Circuit pattern formation step (4)) The circuit pattern formation step (4) is a step of forming a circuit pattern on the above interlayer insulating layer after the above roughening treatment step (3). From the viewpoint of forming fine wiring, it is preferable to form the circuit pattern by a semi-additive process. Conductivity of the vias is achieved together with the formation of the circuit pattern by the semi-additive process. In the semi-additive process, first, electroless copper plating treatment is performed using a palladium catalyst or the like on the entire surface of the via bottom, the via wall surface, and the interlayer insulating layer after the above roughening treatment step (3) to form a seed layer 105. The seed layer is for forming a power supply layer for performing electroplated copper plating, and is preferably formed to have a thickness of about 0.1 to 2.0 μm. If the thickness of the seed layer is 0.1 μm or more, it tends to suppress a decrease in connection reliability during electroplated copper plating, and if it is 2.0 μm or less, it is not necessary to increase the etching amount when flash etching the seed layer between wirings, and damage to the wirings during etching can be suppressed.

[0121] The electroless copper plating treatment is performed by depositing metallic copper on the surfaces of vias and the interlayer insulating layer through the reaction between copper ions and a reducing agent. For the above-described electroless plating treatment method and the above-described electrolytic plating treatment method, known methods may be applied and are not particularly limited. Commercially available products can be used as the electroless copper plating solution. Examples of commercially available products include "MSK-DK" manufactured by Atotech Japan Co., Ltd., "Surcup (registered trademark) PEA series" manufactured by Uemura Industry Co., Ltd., and the like.

[0122] After the above-described electroless copper plating treatment, a dry film resist is thermocompression-bonded onto the electroless copper plating by a roll laminator. The thickness of the dry film resist must be greater than the wiring height after electroplating copper. From this perspective, a dry film resist with a thickness of 5 to 30 μm is preferred. As the dry film resist, the "Fotec" series manufactured by Hitachi Chemical Co., Ltd. and the like are used. After the thermocompression bonding of the dry film resist, for example, the dry film resist is exposed through a mask on which a desired wiring pattern is drawn. The exposure can be performed using the same apparatus and light source as those that can be used when forming vias in the photosensitive resin film. After the exposure, the dry film resist is developed using an alkaline aqueous solution to remove the unexposed portions and form a resist pattern 106. After this, an operation to remove the development residues of the dry film resist using plasma or the like may be performed as necessary. After the development, electroplating copper is performed to form a copper circuit layer 107 and perform via filling.

[0123] After the electroplating copper, the dry film resist is peeled off using an alkaline aqueous solution or an amine-based stripper. After the peeling of the dry film resist, removal of the seed layer between the wirings (flash etching) is performed. The flash etching is performed using an acidic solution such as sulfuric acid and hydrogen peroxide and an oxidizing solution. After the flash etching, removal of palladium or the like attached to the portions between the wirings is performed as necessary. The removal of palladium can preferably be performed using an acidic solution such as nitric acid and hydrochloric acid.

[0124] After peeling the above dry film resist or after the flash etching process, preferably a post-bake treatment is performed. The post-bake treatment sufficiently cures the unreacted thermosetting component, and thereby further improves the insulation reliability, curing characteristics, and adhesion to copper plating. Although the thermosetting conditions vary depending on the type of the resin composition and the like, it is preferable that the curing temperature is 150 to 240 °C and the curing time is 15 to 100 minutes. By the post-bake treatment, a manufacturing process of a multilayer printed wiring board by a single photo via method is completed, and the substrate is manufactured by repeating this process according to the required number of interlayer insulation layers. And preferably, a solder resist layer 108 is formed on the outermost layer.

[0125] As described above, the method for manufacturing a multilayer printed wiring board for forming vias using the photosensitive resin composition of the present embodiment has been described. Since the photosensitive resin composition of the present embodiment is excellent in pattern resolution, for example, it is also suitable for forming a cavity for incorporating a chip or a passive element. The cavity can be preferably formed, for example, in the description of the above multilayer printed wiring board, by setting the drawing pattern when exposing the photosensitive resin film to form a pattern to be capable of forming a desired cavity.

[0126] [Semiconductor Package] The present invention also provides a semiconductor package in which a semiconductor element is mounted on the multilayer printed wiring board of the present embodiment. The semiconductor package of the present embodiment can be manufactured by mounting semiconductor elements such as semiconductor chips and memories at predetermined positions on the multilayer printed wiring board of the present embodiment and encapsulating the semiconductor elements with an encapsulating resin or the like.

Examples

[0127] Hereinafter, the present invention will be described in more detail by way of examples, but the present invention is not limited to these examples. In addition, the characteristics of the photosensitive resin composition obtained in each example were evaluated by the method shown below.

[0128] [Method for Measuring Acid Value] The acid value was calculated from the amount of potassium hydroxide aqueous solution required to neutralize the resin obtained in each synthesis example.

[0129] [1. Evaluation of Via Resolution] A copper-clad laminate substrate with a thickness of 1.0 mm (manufactured by Hitachi Chemical Co., Ltd., product name "MCL-E-67") was prepared. The protective film was peeled off from the carrier film and the photosensitive resin film with a protective film manufactured in each example, and the exposed photosensitive resin film was laminated on the above copper-clad laminate substrate using a press-type vacuum laminator (manufactured by Namiki Seisakusho Co., Ltd., product name "MVLP-500") under predetermined lamination conditions (crimping pressure: 0.4 MPa, press hot plate temperature: 80 °C, vacuum drawing time: 25 seconds, lamination press time: 25 seconds, atmospheric pressure: 4 kPa or less) to obtain a laminate having a photosensitive layer. Next, through a negative mask having a mask with a via pattern having an opening diameter of a predetermined size (opening mask diameter size: 5, 8, 10, 15, 20, 30, 40, 50, 60, 70, 80, 90, and 100 μmφ), using an i-line exposure apparatus (manufactured by USHIO Inc., product number "UX-2240SM-XJ-01"), exposure was performed at an exposure amount such that the step tablet number (ST) was 7. Thereafter, using a 1 mass% aqueous sodium carbonate solution, for a time corresponding to 4 times the shortest development time at 30 °C (the shortest time for removing the unexposed portion of the photosensitive layer), 1.765×10 5 Pa of pressure was used for spray development to dissolve and develop the unexposed portion. Next, after exposure using an ultraviolet exposure apparatus at an exposure amount of 2,000 mJ / cm 2 heating was performed at 170 °C for 1 hour to produce a test piece having a cured product of a photosensitive resin composition having a via pattern of a predetermined size on the copper-clad laminate substrate. The above test piece was observed using a metallurgical microscope or a scanning electron microscope, and among the via patterns where openings were confirmed, the opening mask diameter of the smallest via pattern was defined as the minimum opening mask diameter. The smaller the minimum opening mask diameter, the better the resolution of the via.

[0130] [2. Evaluation of Dielectric Loss Tangent] Two photosensitive resin films with the protective film peeled off were laminated, and while having carrier films on both sides, they were exposed with a flatbed exposure machine at 400 mJ / cm 2 (365 nm), and irradiated with a UV conveyor type exposure machine at 2 J / cm 2 (365 nm). The product thus obtained was heat-treated in a hot air circulation dryer at 170 °C for 1 hour and further at 180 °C for 1 hour, and then cut into a size of 7 cm × 10 cm to obtain an evaluation sample. The obtained evaluation sample was dried in a hot air circulation dryer at 105 °C for 10 minutes, and the dielectric loss tangent was measured by the split post dielectric resonator method (SPDR method).

[0131] Synthesis Example 1 (Synthesis of acid-modified vinyl group-containing epoxy resin A-1) 500 parts by mass of bisphenol F type epoxy resin (manufactured by DIC Corporation, trade name "EXA-7376"), 72 parts by mass of acrylic acid, 0.5 part by mass of hydroquinone, and 150 parts by mass of carbitol acetate were charged into a reaction vessel, heated to 90 °C, and stirred to dissolve the mixture. Next, the obtained solution was cooled to 60 °C, 2 parts by mass of benzyltrimethylammonium chloride was charged, heated to 100 °C, and reacted until the acid value of the solution reached 1 mgKOH / g. To the solution after the reaction, 230 parts by mass of tetrahydrophthalic anhydride and 85 parts by mass of carbitol acetate were added, heated to 80 °C, and reacted for 6 hours. Then, it was cooled to room temperature and diluted with carbitol acetate so that the solid content concentration became 60% by mass to obtain acid-modified vinyl group-containing epoxy resin A-1.

[0132] Synthesis Example 2 (Synthesis of acid-modified vinyl group-containing epoxy resin A-2) 250 parts by mass of a dicyclopentadiene-type epoxy resin (manufactured by Nippon Kayaku Co., Ltd., trade name "XD-1000", an epoxy resin having a structure represented by the above general formula (A-2)), 70 parts by mass of acrylic acid, 0.5 parts by mass of methylhydroquinone, and 120 parts by mass of carbitol acetate were charged into a reaction vessel, heated to 90 °C, and stirred to dissolve the mixture. Next, the obtained solution was cooled to 60 °C, 2 parts by mass of triphenylphosphine was added, and the mixture was heated to 100 °C and reacted until the acid value of the solution reached 1 mgKOH / g. To the solution after the reaction, 98 parts by mass of tetrahydrophthalic anhydride and 850 parts by mass of carbitol acetate were added, heated to 80 °C, and reacted for 6 hours. Thereafter, the mixture was cooled to room temperature, and the solvent was distilled off so that the solid content concentration became 65% by mass to obtain an acid-modified vinyl group-containing epoxy resin A-2.

[0133] [Preparation of Photosensitive Resin Composition] Examples 1 to 5, Reference Example 1, Comparative Example 1 (1) Production of Photosensitive Resin Composition The composition was blended according to the blending compositions shown in Tables 1 and 2 (the units of the numerical values in the tables are parts by mass, and in the case of solutions, they are the amounts in terms of solid content), and kneaded with a three-roll mill. Thereafter, methyl ethyl ketone was added so that the solid content concentration became 65% by mass to obtain a photosensitive resin composition. (2) Production of Photosensitive Resin Film A polyethylene terephthalate film having a thickness of 16 μm (manufactured by Teijin Limited, trade name "G2-16") was used as a carrier film, and the photosensitive resin composition prepared in each example was applied onto the carrier film so that the film thickness after drying became 25 μm, and dried at 75 °C for 30 minutes using a hot air convection dryer to form a photosensitive resin film (photosensitive layer). Subsequently, a polyethylene film (manufactured by Tamapoly Co., Ltd., trade name "NF-15") was laminated as a protective film on the surface of the photosensitive resin film (photosensitive layer) opposite to the side in contact with the carrier film to produce a photosensitive resin film in which the carrier film and the protective film were laminated.

[0134] Using the prepared photosensitive resin film, each evaluation was carried out according to the above method. The results are shown in Tables 1 and 2.

[0135]

Table 1

[0136]

Table 2

[0137] Each component used in Tables 1 and 2 is as follows. [(A) Photopolymerizable compound] · Acid-modified vinyl group-containing epoxy resin A-1: Acid-modified vinyl group-containing epoxy resin A-1 prepared in Synthesis Example 1 · Acid-modified vinyl group-containing epoxy resin A-2: Acid-modified vinyl group-containing epoxy resin A-2 prepared in Synthesis Example 2

[0138] [(B) Epoxy resin] · Bisphenol F type epoxy resin (bisphenol type epoxy resin, epoxy equivalent 192 / eq) · Naphthol novolak type epoxy resin (manufactured by Nippon Kayaku Co., Ltd., trade name "NC-7000-L", epoxy equivalent 231 g / eq) · Biphenyl aralkyl type epoxy resin (manufactured by Nippon Kayaku Co., Ltd., trade name "NC-3000-L", epoxy equivalent 272 g / eq)

[0139] [(C) Active ester compound] · Active ester compound C-1: Active ester compound having a dicyclopentadiene type diphenol structure (manufactured by DIC Corporation, trade name "HPC-8000-65T", ester group equivalent 223 g / eq) · Active ester compound C-2: Polyarylate resin (manufactured by Unitika Ltd., trade name "V-575", ester group equivalent: 210 g / eq, polyarylate resin having an active ester group formed from dicarboxybenzene and bisphenols) · Active ester compound C-3: Polyarylate resin (manufactured by Unitika Ltd., trade name "W-575", ester group equivalent: 220 g / eq, polyarylate resin having an active ester group formed from dicarboxybenzene and bisphenols) · Active ester compound C-4: Manufactured by DIC Corporation, trade name "EXB-8"

[0140] [(D) Crosslinking agent] · Dipentaerythritol hexaacrylate · Tricyclodecane dimethanol diacrylate

[0141] [(E) Elastomer] · Polyester-based elastomer (manufactured by Hitachi Chemical Co., Ltd., trade name "SP1108") · Epoxidized polybutadiene (manufactured by Daicel Chemical Industries, Ltd., trade name "PB3600") · Maleic anhydride-modified polybutadiene (manufactured by Cray Valley, trade name "Ricon®130MA8", number of maleic anhydride modification groups: 2, 1,4-trans isomer + 1,4-cis isomer: 72%)

[0142] [(F) Photoinitiator] · Photoinitiator 1: 2-Methyl-[4-(methylthio)phenyl]morpholino-1-propanone (acetophenones) · Photoinitiator 2: 2,4-Diethylthioxanthone (thioxanthones)

[0143] [(G) Inorganic filler] · Silica 1: Fused spherical silica with an average particle diameter of 0.5 μm (product treated with a coupling agent) · Silica 2: Fused spherical silica with an average particle diameter of 0.18 μm (product treated with a coupling agent)

[0144] [(H) Curing accelerator] · Isocyanate-masked imidazole (manufactured by Daiichi Kogyo Seiyaku Co., Ltd., trade name "G8009L")

[0145] [(I) Epoxy resin curing agent] · Triazine ring-containing phenol novolak resin (manufactured by DIC Corporation, trade name "LA7052")

[0146] [(J) Additive] · 4,4'-Bisdiethylaminobenzophenone · 1,3,5-Triazine-2,4,6-triamine · Silicone-based foam stabilizer · Pigment

[0147] From Table 1, it can be seen that the photosensitive resin compositions of Examples 1 and 2 of this embodiment can reduce the dielectric tangent while maintaining good resolution (minimum aperture diameter) compared with the photosensitive resin composition of Comparative Example 1 that does not contain component (C). Furthermore, the photosensitive resin compositions of Reference Example 1 and Examples 3 to 5 in Table 2 all have a low dielectric tangent. Among them, it can be seen that the photosensitive resin compositions of Examples 3 to 5 can achieve a significantly low dielectric tangent.

Explanation of Reference Signs

[0148] 100A Multilayer printed wiring board 102 Circuit pattern 103 Interlayer insulating layer 104 Via (via hole) 105 Seed layer 106 Resist pattern 107 Copper circuit layer 108 Solder resist layer

Claims

1. (A) a photopolymerizable compound having an ethylenically unsaturated group and an acidic substituent, (B) an epoxy resin, and (C) an active ester compound, Contains The photopolymerizable compound (A) having an ethylenically unsaturated group and an acidic substituent contains an alicyclic structure represented by the following general formula (A-1): A photosensitive resin composition comprising, as the (B) epoxy resin, a bisphenol-type epoxy resin and an aralkyl-type epoxy resin. 【Chemistry 1】 (In the formula, R Ａ１ represents an alkyl group having 1 to 12 carbon atoms, and may be substituted anywhere in the alicyclic structure. １ is an integer from 0 to 6. * is a binding site to other structures.)

2. 2. The photosensitive resin composition according to claim 1, wherein the (A) photopolymerizable compound having an ethylenically unsaturated group and an acidic substituent has an acid value of 20 to 200 mgKOH / g.

3. 3. The photosensitive resin composition according to claim 1, wherein the (C) active ester compound is a compound having two or more active ester groups in one molecule, and the two or more active ester groups are active ester groups formed from a polyvalent carboxylic acid compound and a compound having a phenolic hydroxyl group.

4. The photosensitive resin composition according to any one of claims 1 to 3, wherein an equivalent ratio [epoxy group / acidic substituent] between the acidic substituent of the photopolymerizable compound (A) having an ethylenically unsaturated group and an acidic substituent and the epoxy group of the epoxy resin (B) is 0.5 to 6.0, and an equivalent ratio [active ester group / epoxy group] between the epoxy group of the epoxy resin (B) and the active ester group of the active ester compound (C) is 0.01 to 0.

4.

5. The photosensitive resin composition according to any one of claims 1 to 4, further comprising (D) a crosslinking agent having two or more ethylenically unsaturated groups and no acidic substituent.

6. 6. The photosensitive resin composition according to claim 5, wherein the (D) crosslinking agent having two or more ethylenically unsaturated groups and no acidic substituent is a di(meth)acrylate having an alicyclic skeleton.

7. The photosensitive resin composition according to any one of claims 1 to 6, further comprising an elastomer (E), as the elastomer (E), an elastomer having an ethylenically unsaturated group and an acidic substituent.

8. The photosensitive resin composition according to any one of claims 1 to 7, further comprising (F) a photopolymerization initiator.

9. The photosensitive resin composition according to any one of claims 1 to 8, further comprising (H) a curing accelerator.

10. The photosensitive resin composition according to any one of claims 1 to 9, which is used for forming one or more selected from the group consisting of a photovia and an interlayer insulating layer.

11. A photosensitive resin film comprising the photosensitive resin composition according to any one of claims 1 to 10.

12. 12. A multilayer printed wiring board comprising an interlayer insulating layer formed using the photosensitive resin composition according to any one of claims 1 to 10 or the photosensitive resin film according to claim 11.

13. A semiconductor package comprising the multilayer printed wiring board according to claim 12 and a semiconductor element mounted thereon.

14. A method for producing a multilayer printed wiring board, comprising the following steps (1) to (4): Step (1): A step of laminating the photosensitive resin film according to claim 11 onto one or both sides of a circuit board. Step (2): A step of forming an interlayer insulating layer having vias by exposing and developing the photosensitive resin film laminated in the step (1). Step (3): A step of roughening the via and the interlayer insulating layer. Step (4): forming a circuit pattern on the interlayer insulating layer.

Images