TW201401951A - Circuit formation method of printed circuit board, thermalsetting resin composition and printed circuit board - Google Patents

Abstract

The subject of the present invention is to provide a circuit formation method of printed circuit board, a thermalsetting resin composition, and a printed circuit board, which may form the fine circuit without a pre-coating process and a polishing process for excessively formed metal on a coating film or a conductive coating, and achieve excellent processability of laser irradiation for insulation resin layer and bonding characteristic between the insulation resin layer and the circuit film. The solution of the present invention is to provide a circuit formation method of printed circuit board, which is characterized in including a concave structure formation process for irradiating ultraviolet laser have the pulse width in nano second level on the insulation resin layer on the metal foil laminated plate with ultraviolet absorbability to remove the insulation resin layer for forming the concave structure; and, a dispersion liquid coating process for coating the dispersion liquid containing metal nanometer particles using ink-jet method inside the concave structure formed by the aforementioned concave structure formation process.

Description

Circuit forming method of printed wiring board, thermosetting resin composition, and printed wiring board

The present invention relates to a circuit forming method for a printed wiring board, a thermosetting resin composition using the same, and a printed wiring board, which does not require a pre-plating pretreatment process which imposes a large burden on the environment, and a plating film which is formed excessively. In the polishing process of a metal film such as a conductive coating film, a fine circuit can be formed, and the processability of the laser irradiation with respect to the insulating resin layer and the adhesion between the insulating resin layer and the connection circuit film or the wiring film are good.

In general, a circuit forming method of a printed wiring board has a subtractive method, a full-additive method, or a semi-additive method.

The subtractive method is a method of forming a circuit by etching a metal foil by penetrating a resist. However, since the circuit is formed by the etching liquid, it is not suitable to form a fine circuit. On the other hand, the full addition method or the semi-addition method is a method of forming a circuit by electroless plating, but in these circuit formation methods, it is affected by the unevenness of the insulating resin layer subjected to the roughening treatment, and Problems such as poor connection or disconnection of the circuit are caused, and it is not suitable to form a fine circuit.

In addition, in recent years, in the method of forming a fine circuit which is required to increase the density and the miniaturization of the printed wiring board, there is proposed a method as disclosed in Patent Documents 1 and 2, which is formed on the surface of the substrate by using a laser or the like. After a trench or a via hole, electroless plating and electrolytic plating are applied to the inside of the trench or the via hole to form a fine circuit.

Further, a method of forming a fine circuit inside a trench or a via hole is proposed as disclosed in Patent Documents 3 to 5, which is formed in a trench or a via hole by an inkjet method after a pre-plating treatment process. The catalyst layer, or a metal layer called a plated core, is then formed into a fine circuit by electroless plating.

Further, Patent Document 6 discloses a method of filling a trench or a via hole with a conductive paste by an ink jet method to form a fine circuit.

2 and 3 are schematic model diagrams of a conventional circuit forming method. 2 is a process of applying electroless plating by a pretreatment agent or a water repellent 9 after laser irradiation (FIG. 2(c)), and then coating the catalyst core 10 by an inkjet method to perform no treatment. The method of electrolytic plating. Further, in the method described in FIG. 3, after the connection circuit film or the wiring film is formed, polishing is performed by the polishing machine 8 to planarize.

The term "pre-electroless plating treatment" as used herein refers to a process for selectively attaching a plating or a process for making a state suitable for plating adhesion. In addition, in the electroless plating pretreatment process, the desmear treatment project is not included.

[Previous Technical Literature]

[Patent Literature]

[Patent Document 1] Japanese Patent Laid-Open Publication No. 2009-117415

[Patent Document 2] U.S. Patent No. 7312103

[Patent Document 3] Japanese Laid-Open Patent Publication No. 2011-151172

[Patent Document 4] Japanese Patent Laid-Open Publication No. 2009-81212

[Patent Document 5] Japanese Patent Laid-Open Publication No. 2010-21301

[Patent Document 6] Japanese Patent Laid-Open Publication No. 2004-152934

However, in the methods disclosed in the above Patent Documents 1 and 2, since the excess formed metal film is removed after the plating process, it is necessary to separately provide a polishing process (flattening process) such as CMP (Chemical Mechanical Polishing).

Further, in the methods disclosed in the above Patent Documents 3 to 5, it is necessary to pass a conventional pre-plating treatment process before applying the electroless plating treatment, or to provide a water-repellent resin layer in a portion where the plating layer is not required.犠 层 layer.

Further, in the method disclosed in the above Patent Document 6, after the conductive paste is filled in the inside of the groove or the through hole, in order to remove the conductive coating film which is formed excessively, it is necessary to additionally provide a polishing process using a buffing machine or a belt sander ( Flattening engineering). As such, the methods proposed in the above patent documents are subject to complicated engineering, and thus there is a problem that the manufacturing cost is increased.

Furthermore, in recent years, there has been a search for a printed wiring board. The road forming method, the thermosetting resin composition, and the printed wiring board can provide laser processing properties when forming fine grooves or through holes, and the connection circuit film or wiring film filled with the conductive paste and the insulating resin layer. Synergy is also taken into account.

Accordingly, an object of the present invention is to provide a circuit forming method for a printed wiring board, a thermosetting resin composition using the same, and a printed wiring board which does not require a plating pretreatment process and a plating for excess formation. A polishing process of a metal film such as a film or a conductive coating film can form a fine circuit, and the processability of the laser irradiation with respect to the insulating resin layer and the adhesion between the insulating resin layer and the connection circuit film or the wiring film are good.

In order to solve the above problems, the inventors of the present invention have focused on the results of the research and found that by designing a method, a specific laser is used to form a concave portion structure in an insulating resin layer, and an ink jet method is applied to the inside of the concave portion to coat the metal nanoparticle. The above problems can be solved by the construction of the dispersion, and the present invention is completed. Further, it has been found that a specific thermosetting resin composition is suitable for the above method.

In other words, the method for forming a circuit of a printed wiring board according to the present invention includes a structure for forming a recessed portion, and is an insulating resin layer having ultraviolet absorbing properties on a metal foil laminated board, and has a pulse twist of nanoseconds. The ultraviolet laser is irradiated, whereby the insulating resin layer is removed to form a concave portion structure; and the dispersion coating process is performed, and the dispersion containing the metal nanoparticles is coated by an inkjet method inside the concave portion structure formed by the recess structure formation process. liquid.

In the circuit forming method of the printed wiring board of the present invention, the recess structure is preferably one or more of a groove and a through hole.

Further, in the circuit forming method of the printed wiring board of the present invention, in the dispersion coating process, it is preferable that the dispersion liquid is filled in the entire inside of the concave portion structure.

Further, in the circuit forming method of the printed wiring board of the present invention, it is preferable to have an electroless plating process after the dispersion coating process.

A printed wiring board according to the present invention is characterized by comprising a circuit obtained by a circuit forming method of any of the above printed wiring boards.

The thermosetting resin composition of the present invention is a thermosetting resin composition for forming an insulating resin layer in the circuit forming method of any of the above-described printed wiring boards, and is characterized in that it contains one or more of the following: A) a polyimine resin having a linear structure, (B) an epoxy resin having a polycyclic aromatic hydrocarbon ring, and (C) an ultraviolet absorber.

Further, in the thermosetting resin composition of the present invention, the epoxy resin having a polycyclic aromatic hydrocarbon ring (B) is a naphthalene epoxy resin and an anthracene epoxy resin. More than one is preferred.

According to the present invention, it is possible to provide a circuit forming method for a printed wiring board, a thermosetting resin composition using the same, and a printed wiring board which does not require a plating pretreatment process, and a plating film or a conductive coating film. In the polishing process of the excessively formed metal, a fine circuit can be formed, and the processability of the laser irradiation to the insulating resin layer and the adhesion of the insulating resin layer to the connection circuit film or the wiring film are good.

1‧‧‧metal foil laminate

1A‧‧‧Insulating resin layer

1B‧‧‧ metal layer

2A‧‧‧ trench

2B‧‧‧through hole

3‧‧‧Dispersion containing metal nanoparticles

4A‧‧‧ wiring film

4B‧‧‧Connected circuit film

5‧‧‧ spout nozzle

6‧‧‧UV laser

7‧‧‧ hatching

8‧‧‧ Grinder

9‧‧‧Pretreatment agent or water repellent

10‧‧‧catalyst (plating core)

11‧‧‧ Electroless plating

Fig. 1 is a schematic view showing a schematic example of a method of forming a circuit of a printed wiring board of the present invention.

Fig. 2 is a schematic view showing an example of a circuit forming method of a conventional printed wiring board.

Fig. 3 is a schematic view showing an example of a circuit forming method of a conventional printed wiring board.

A circuit forming method of a printed wiring board according to the present invention is characterized in that it has a recess structure forming process and a dispersion liquid coating process. A suitable aspect of the circuit forming method of the printed wiring board of the present invention will be described using FIG. That is, by the laser irradiation (Fig. 1 (a)), a concave structure such as the groove 2A or the through hole 2B is formed (Fig. 1 (b)), and the dispersion containing the metal nanoparticles is applied by an inkjet method ( (c11) or (c21)). When the dispersion liquid is to be applied to a part of the concave portion structure, it is preferable to laminate the metal by electroless plating to fill or coat the inside of the concave portion structure (Fig. 1 (c22)).

A suitable way is to borrow after the dispersion is filled or after electroless plating. The metal nanoparticles are bonded by a firing treatment to form a connection circuit film or a wiring film (Fig. 1 (d)).

Thereafter, the connection circuit film or the wiring film may be coated on the insulating layer (Fig. 1(e)), or gold bumps or solder bumps may be bonded. In addition, the same structure can be repeated to form a laminated structure.

Fig. 1(f) is a model diagram of a printed wiring board in which a circuit is formed by the method of the present invention as viewed from above. The details of each project are described below.

[Concave structure formation project]

The recess structure forming process is an ultraviolet resin having an ultraviolet absorbing property on a metal-clad laminate, and is irradiated with an ultraviolet laser having a pulse width of nanoseconds, thereby removing the insulating resin layer. To form the construction of the recess structure. In other words, as shown in Fig. 1(a), for the metal foil laminated board having the insulating resin layer 1A and the metal layer 1B, an ultraviolet laser having a pulse width of nanoseconds is irradiated from above the insulating resin layer 1A. As a result, a concave structure as shown in Fig. 1(b) is formed. The recessed portion preferably has one or more of the groove 2A and the through hole 2B. The formation of the groove 2A is performed by removing a part of the insulating resin layer 1A among the irradiation portions of the ultraviolet laser, and the metal layer 1B is not exposed. The through hole 2B is formed by exposing all the insulating resin layers 1A in the irradiation portion of the ultraviolet laser and exposing the metal layer 1B.

(ultraviolet laser)

The ultraviolet laser is a laser having an ultraviolet ray (referred to as a wavelength of 200 nm to 400 nm) as an oscillation wavelength. In the present invention, a third harmonic laser (351 nm), YAG or YVO ₄ crystal mediated by YLF crystal is used. A third harmonic laser (355 nm) for the medium is particularly suitable.

The ultraviolet laser irradiation method includes pulse irradiation and continuous irradiation. However, pulse irradiation does not cause thermal expansion or cracking of the insulating resin layer on the periphery of the concave portion structure. Therefore, pulse irradiation is employed in the present invention. Further, the repetition frequency of the pulse irradiation is preferably from 1 kHz to 500 kHz, more preferably from 10 kHz to 100 kHz.

If it is less than 1 kHz, laser processing takes a long time, which may result in reduced productivity. On the other hand, if it exceeds 500 kHz, the irradiation time per pulse is shortened by the nanosecond laser, so decomposition, vaporization, and heat storage of the insulating resin layer are liable to occur, so that the insulating resin layer may be removed after the removal of the insulating resin layer. The material causes damage such as cracks. Further, the focus position of the ultraviolet laser is preferably on the surface of the insulating resin layer.

In the present invention, the pulse intensity of the ultraviolet laser is in the order of nanoseconds. By using a nanosecond pulsed ultraviolet laser, the inner surface of the formed recess has an appropriate surface roughness, and the wiring formed in the insulating resin layer and the recess structure by an anchor effect High adhesion can be obtained between the film and the connection circuit film. Preferably, the pulse width is from 1 to 100 ns, more preferably from 1 to 50 ns.

The irradiation energy of the ultraviolet laser is expressed by the irradiation energy [μJ/pulse] per pulse. In the present invention, it is preferably from 0.5 μJ/pulse to 50 μJ/pulse, more preferably from 1 μJ/pulse to 10 μJ/pulse. . At the time of irradiation, it is carried out with the same irradiation energy. If not When the thickness is 0.5 μJ/pulse, the insulating resin layer can hardly be removed, so that it is difficult to form through holes and grooves, which is not suitable. On the other hand, when it exceeds 50 μJ/pulse, the insulating resin layer may be removed, and the substrate may be damaged by cracks or the like.

The number of exposures of the above ultraviolet laser must be continued The number of times of irradiation is proportional to the film thickness of the insulating resin layer until the desired recess structure is formed. Specifically, when a through hole is to be formed, the number of times of laser irradiation necessary to remove the insulating resin layer having a film thickness of 10 to 20 μm and reaching the metal layer is preferably from 1 to 50 times. Further, the number of times of laser irradiation necessary for removing the insulating resin layer having a film thickness of 20 to 30 μm to form a through hole reaching the metal layer is preferably from 1 to 100 times, more preferably from 10 times to 80 times. If the number of times of irradiation is too large, damage may occur due to cracks or removal of the metal layer after removing the insulating resin layer. Similarly, when a groove is to be formed, the laser beam is irradiated while moving at an arbitrary processing speed and number of irradiation points. Further, when a trench is to be formed, a part of the insulating resin layer is removed, so that the thickness of the removed layer is lower than the film thickness of 10 to 20 μm or 20 to 30 μm when the via hole is formed.

a concave structure shape formed by the above ultraviolet laser, The through hole is expressed as a ratio of the diameter D of the surface of the insulating resin layer to the diameter d of the surface of the metal layer (the bottom surface of the through hole), that is, expressed by the formula (d/D) × 100 [%]. Further, the groove is similarly expressed as the ratio of the width d' of the surface of the insulating resin layer and the width D' of the bottom surface (the bottom surface of the groove) of the insulating resin layer. In the present invention, the through holes and the grooves are preferably 50% or more, more preferably 70% or more. If it is less than 50%, the bottom surface of the through hole or the bottom surface of the groove may be too narrow, which may cause adhesion of solder or metal plating. question. Further, if it exceeds 100%, the through holes and the grooves may be reversely pushed out, which is not suitable.

In addition, the diameter of the through hole formed by the above ultraviolet laser and The groove width, which is the diameter D of the surface of the insulating resin layer, is preferably from 10 μm to 70 μm, more preferably from 10 μm to 45 μm. By using an ultraviolet laser, for example, it is possible to provide a printed wiring board which can correspond to a narrow pitch circuit wiring, which is a widely used carbon dioxide gas laser and a composition which cannot be used.

After the ultraviolet laser irradiation, desmear treatment may be performed to decompose and remove residual components such as processing residues after ultraviolet laser processing. The desmear treatment may be carried out by any known method, for example, a dry degumming method using a plasma generating apparatus under vacuum, or a wet degumming method using a desmear treatment liquid such as a permanganate solution.

(metal foil laminate)

The metal foil laminated board has a structure in which an insulating resin layer is formed on a metal layer, as shown by reference numeral 1 in Fig. 1(a). The metal layer is a wiring pattern formed on a surface of a substrate by a conductor such as copper or silver, and is preferably a copper foil laminate.

The substrate of the above metal layer is not particularly limited as long as it is used for a printed wiring board. For example, as a material, paper phenol, paper epoxy, epoxy glass cloth, polyimide glass, and epoxy glass are used. Cloth/non-woven fabric, epoxy glass cloth/paper, epoxy synthetic fiber, epoxy amide, polyimine resin, polyphenylene Ether Resin, double Bismaleimide-Triazine Resin, Polyetherimide Resin, Fluorine. Polyethylene. PPO. Cyanate ester or the like, or a glass substrate, a ceramic substrate, or a wafer plate.

(insulating resin layer)

The insulating resin layer is composed of an insulating resin composition having ultraviolet absorbing properties. By having ultraviolet absorbing properties, it is suitable to be removed by ultraviolet laser light, and a concave structure can be formed. The resin composition for forming the insulating resin layer may be any one having ultraviolet absorbing property and insulating property, but the thermosetting resin composition of the present invention described below is particularly preferable.

[Dispersion Coating Engineering]

The dispersion coating process is a process in which a dispersion containing metal nanoparticles is applied to the inside of the concave structure by an inkjet method. As shown in Fig. 1 (c11), the dispersion liquid may be entirely filled in the concave portion structure, or as shown in Fig. 1 (c21), a part of the concave portion structure, preferably the bottom portion, may be coated with a dispersion liquid. The inkjet method can be either a piezoelectric type or a thermal bubble type, and can be carried out using a droplet discharge device having a discharge head shown by reference numeral 5 in Fig. 1 . In the inkjet type liquid droplet discharging device, the discharge head 5 having the discharge nozzle for discharging the liquid droplets (dispersion liquid) is moved relative to the metal foil laminated plate, whereby the discharge head 5 is accurately positioned. In the concave portion structure, a certain amount of liquid droplets (dispersion liquid 3 containing metal nanoparticles) is discharged, and falls into the concave structure. In this way, the desired amount of dispersion can be applied at any position. The so-called required amount refers to the concave structure formed by the irradiation of the laser. The amount to be filled with the entire insulating resin layer or the amount of a part of the insulating resin layer. In addition, the metal layer (connecting circuit film or wiring film) containing metal nanoparticles at this time has a volume resistance value of 2 to 100 μΩ. Cm.

Further, after the dispersion is applied, a drying process may be provided, and coating and drying are repeated to fill the dispersion. Any such known one can be used for such an ink jet type droplet discharge device, and a commercially available device can also be used.

Since the dispersion containing the metal nanoparticles is applied by the inkjet method, it is not necessary to remove the electroless plating or the catalyst by etching, and the plating barrier layer can be omitted.

(Dispersions)

The dispersion liquid is one in which metal nanoparticles are dispersed in a solvent. Examples of the solvent include water, ketones, aromatic hydrocarbons, glycol ethers, glycol ether acetates, esters, alcohols, and polyalcohols. (polyol), aliphatic hydrocarbon, petroleum solvent, and the like. More specifically, for example, ketones such as methyl ethyl ketone (Kethyl Ethyl Ketone) and cyclohexanone (Ketone); aromatic hydrocarbons such as toluene, xylene, and tetramethylbenzene; (Cellosolve), Methyl Cellosolve, Butyl cellosolve, Carbitol, Methyl Carbitol, Diethylene Glycol Butyl Carbitol, Propylene Glycol Monomethyl Ether, Dipropylene Glycol Monomethyl Ether (Dipropylene Glycol Monomethyl Ether), Dipropylene Glycol Dimethyl Ether, Triethylene Glycol Monoethyl Ether and other glycol ethers; Ethyl Acetate, Butyl Acetate (Butyl) Acetate), Dipropylene Glycol Methyl Ether Acetate, Propylene Glycol Methyl Ether Acetate, Propylene Glycol Ethyl Ether Acetate, Propylene Glycol Butyl Ether Acetate and other esters; Ethanol, Propanol, Ethylene Glycol, Propylene Glycol, Butylene Glycol, 1,3-Butanediol (1) , 3-Butylene Glycol) 1,4-Butylene Glycol, 2,3-Butylene Glycol, Pentanediol, Hexanediol ), an alcohol such as Octanediol Isobornyl Hexanol or terpineol, such as Mononotepene Alcohol; Octane, Decane, etc. Aliphatic hydrocarbon; petroleum ether (Petroleum Ether ), petroleum naphtha, hydrogenated petroleum naphtha, petroleum solvent such as Solvent Naphtha, and the like. These solvents may be used alone or in combination of two or more.

The metal of the metal nanoparticle contained in the dispersion may be, for example, gold, silver, copper, palladium, tungsten, nickel, rhenium, ruthenium, lead, indium, tin, or the like. Titanium, aluminum, etc., and alloys thereof, oxides thereof, and ITO (Indium Tin Oxide), indium oxide, or the like can also be used. Among them, copper and silver are preferably used. Further, the surface of the metal nanoparticles may be treated with a nitrous acid such as sodium citrate or ammonium citrate, an ammonium ion, a quaternary ammonium compound or a nitrogen compound such as an amine.

The above metal nanoparticles (metal particles having an average particle diameter of nm) preferably have an average particle diameter of 5 to 300 nm, preferably 10 to 200 nm, more preferably 10 to 100 nm. The average particle diameter can be obtained by observing metal particles by an electron microscope such as TEM or SEM, and randomly extracting 100 metal particles and averaging them. The average particle diameter of the metal particles falls within the above range, that is, the nanometer size, whereby the surface roughness of the electrode or the wiring which is formed by printing and sintering the dispersion liquid can be lowered, and the firing temperature can be remarkably lowered. It will exhibit completely different properties from metal particles of a general particle size (μm grade).

The method for producing the metal nanoparticles is not particularly limited, and for example, it may be any one of a gas phase synthesis method or a liquid phase reduction method. Among the commercially available silver particles having the above average particle diameter, for example, silver nanoparticle dry powder-1, -2, -3, -4, etc., manufactured by DOWA ELECTRONICS. Commercially available products of copper nanoparticles include, for example, copper nanoparticles Cu-001 manufactured by IOX Corporation.

Further, the dispersion may contain hydride fine particles of a metal such as copper, nickel or palladium as metal nanoparticles. Since the hydride fine particles are present in a state in which a metal atom is bonded to a hydrogen atom, it is less likely to be oxidized than the fine particles of the metal itself in an air environment. Metal hydride microparticles, for example, by the method described in Japanese Patent No. 4747839 And manufacturing. That is, it can be produced by dissolving a water-soluble compound of the above metal in water, adjusting the pH to 3 or less, and then adding an amino group (Amino), an amine group (Amide), and a sulfonamide. One or more functional groups selected from the group consisting of Sulfanilyl, Sulfanyl, Hydroxyl, Carboxy, Carbonyl, and Ether (Oxy) The organic compound, with an organic liquid, is added to the reducing agent while stirring to reduce the metal ions in the aqueous solution.

The concentration of metal nanoparticles in the above dispersion is from 1 to 85 The mass % is better, and 10 to 50% by mass is more preferable. In addition, the viscosity of the dispersion (25 ° C) is 0.5 ~ 10000 mPa. s is better, 1~100mPa. s is better. Viscosity can be determined, for example, by a Cone-Plate viscometer.

(electroless plating project)

In the method of the present invention, when the dispersion liquid is applied to a part of the concave structure in the dispersion coating process, as shown in (c21) and (c22) of FIG. 1, the metal is coated or filled by electroless plating. The interior of the recess is preferably internal. As described above, the dispersion containing the metal nanoparticles is applied to the inside of the concave structure by an inkjet method, and the metal film is dried by removing the solvent, thereby exhibiting a catalyst core or starting point of electroless plating. As a result, the metal will gradually build up. Examples of electroless plating include electroless copper plating, electroless nickel plating, electroless nickel-tungsten alloy plating, electroless tin plating, electroless gold plating, and the like, and electroless copper plating is preferred. Electroless plating can be used Any of the well-known methods and solutions are not particularly limited. For example, as the electroless copper plating solution, a material containing copper sulfate, EDTA, Glyoxylic Acid, sodium hydroxide, and having a pH adjusted to 12.5 can be used. Further, as the electroless nickel plating solution, for example, a material containing nickel sulfate, sodium hypophosphite, citrate, and pH adjusted to 8 to 9 can be used. As the electroless plating method, the substrate may be immersed in the plating solution under heating, and it is preferred to immerse the substrate in the plating solution at a temperature of 60 to 80 ° C for 30 to 600 minutes. Further, in the case of immersion, it is preferred to stir the plating solution.

(burning treatment project)

In the circuit forming method of the printed wiring board of the present invention, preferably, after the dispersion coating process or the electroless plating, the substrate is subjected to a baking treatment to thereby sinter the metal nanoparticles to form a wiring film or a connection. Circuit film. The firing is preferably carried out in the atmosphere or in a nitrogen atmosphere at a temperature of 50 to 200 ° C for 5 to 60 minutes. Further, it is preferred to carry out a drying process before the baking treatment to remove the solvent in the dispersion.

[thermosetting resin composition]

The thermosetting resin composition of the present invention is a thermosetting resin composition which is suitable for forming an ultraviolet absorbing insulating resin layer on the metal foil laminated board used in the circuit forming method of the present invention. And containing one or more of the following: (A) a polyimine resin having a linear structure, (B) an epoxy resin having a polycyclic aromatic hydrocarbon ring, and (C) UV absorber. When the (C) ultraviolet absorber is contained as a component having ultraviolet absorbing property, the thermosetting resin composition must contain a thermosetting resin component.

Among the components having ultraviolet absorbing properties, the (A) polyimine resin having a linear structure preferably has a linear structure and contains a Cyclic Imide bond in the resin skeleton. Further, (A) a polyimine resin having a linear structure is preferably an aromatic polyimide resin, and is preferably soluble in an organic solvent. The aromatic polyimine resin herein is preferably a resin having a structural unit represented by the following general formula, and preferably has a reactive functional group in the molecule. The position of the reactive functional group is not particularly limited and may be at the end or at the center.

(Wherein, R ₃ represents a tetravalent organic group of the aromatic ring, R ₄ represents a divalent organic group of the aromatic ring. However, R ₃ having a reactive functional group is 5 monovalent organic group, R ₄ reactive The functional group is a trivalent organic group.)

(A) Specific examples of the polyimine resin having a linear structure, for example, V-8005 (manufactured by DIC Corporation); GPI-NT, -HT (manufactured by Kyoei Chemical Industry Co., Ltd.); RIKACOAT SN-20, -PN -20, -CN-20 (manufactured by Nippon Chemical and Chemical Co., Ltd.), etc. They may be used alone or in combination of two or more.

Further, the above (A) has a linear structure of a polyimide resin, and any of the polyimides having ultraviolet absorbing properties may be used in addition to the specific examples.

The content of the (A) polyimine resin having a linear structure in the composition is preferably from 10 to 90% by mass based on the total solid content of the thermosetting resin composition of the present invention. More preferably, it is 20 to 60% by mass. When the polyimine resin having a linear structure (A) is less than 10% by mass, the heat resistance is lowered, so that the effect of the present invention may not be exhibited, and if it exceeds 90% by mass, the hardenability may be insufficient. The function of the hard coating film may not be exhibited.

Among the components having ultraviolet absorbing property, the epoxy resin having a polycyclic aromatic hydrocarbon ring (B) is a ring containing a polycyclic aromatic hydrocarbon ring having two or more aromatic rings condensed in a resin skeleton. Oxygen resin. Among these epoxy resins having a polycyclic aromatic hydrocarbon ring, from the viewpoint of obtaining good ultraviolet laser processability, in particular, naphthalene epoxy resin or ruthenium having high absorbability in an ultraviolet region. Anthracene epoxy resin is preferred.

Specific examples of the above (B) epoxy resin having a polycyclic aromatic hydrocarbon ring, as a naphthalene epoxy resin, for example, HP-4032, HP-4032D, HP-4700, HP-4710, HP-4770, EXA- 4700, EXA-4710, EXA-7311, EXA-9900 (all manufactured by DIC); ESN-175, ESN-355, ESN-375 (all manufactured by Nippon Steel Chemical Co., Ltd.); For example, there is YX-8800 (manufactured by Mitsubishi Chemical Corporation). They may be used alone or in combination of two or more.

(This type of (B) epoxy tree with polycyclic aromatic hydrocarbon ring The content of the fat in the composition is preferably from 10 to 90% by mass, and more preferably from 20 to 60% by mass based on the total solid content of the thermosetting resin composition of the present invention.

Among the components having ultraviolet absorption, the above (C) ultraviolet Line absorbers, for example, Benzophenone derivatives, Benzoate derivatives, Benzotriazole derivatives, Triazine derivatives, Benzothiazole derivatives , Cinnamate derivatives, anthranilate derivatives, Dibenzoylmethane derivatives, and the like. For example, 2-Hydroxy-4-methoxybenzophenone, 2-hydroxy-4-n-octyloxybenzophenone (2-Hydroxy-4-n-) Octoxybenzophenone), 2,2'-Dihydroxy-4-methoxybenzophenone, 2,4-Dihydroxy methoxybenzophenone ), 2-Ethylhexyl Salicylate, Phenyl Salicylate, Pt-Butylphenyl Salicylate, 3,5-di-tert-butyl- 2,4-Di-tert-butylphenyl-3,5-Di-tert-butyl 4-Hydroxybenzoate, 3,5-di-tert-butyl- Hexadecyl 3,5-di-tert-butyl-4-hydroxybenzoate, 2-(5-tert-butyl-2-hydroxy)benzotriazole (2'2'-Hydroxy -5'-tert-butylphenyl)benzotriazole), 2-(5-methylphenyl-2-hydroxy) Benzotriazole (2'-Hydroxy-5'-methylphenyl)benzotriazole, 2-(2'-hydroxy-3'-tert-butyl-5'-methylphenyl)-5-chlorobenzotriene 2(2'-Hydroxy-3-tert-butyl-5'-methylphenyl)-5-chlorobenzotriazole, 2-(2'-hydroxy-3',5'-di-tert-butyl)-5-chlorobenzene And 2 (2'-Hydroxy-3', 5'-di-tert-butylphenyl)-5-chlorobenzotriazole, 2-(5-methylphenyl-2-hydroxy)benzotriazole (2 2'-Hydroxy-5'-methylphenyl)benzotriazole), 2-(2'-hydroxy-3',5'-dipentylphenyl)-5-chlorobenzotriazole (2'2'-Hydroxy-3 ',5'-di-tert-amylphenyl)-5-chlorobenzotriazole), Hydroxyphenyl Triazine, Bis-ethylhexyloxyphenol methoxylphenyl triazine, etc. Examples are CHIMASSORB81, TINUVIN120, -NP, -234, -320, -326, -327, -328, -329, -1577ED (manufactured by BASF JAPAN); SUMISORB 200, -250, -300, -340, -350 (made by Sumitomo Chemical Co., Ltd.); ADEKASTAB LA-31, -32, -36 (made by ADEKA).

Further, as the above (C) ultraviolet absorber, it is also possible to It is generally used as a photopolymerization initiator for photoresist layers. Examples of such a photopolymerization initiator include an α-Aminoalkyl Phenone, an Acylphosphine Qxide, an Oxime Ester, a benzophenone compound, and the like. Specific examples of the photopolymerization initiator include, for example, 2-benzyl-2-dimethylamino-1-(4-morpholinylphenyl)butanone-1 (2-Benzyl-2- Dimethylamino-1-(4-morpholinophenyl)-butanone-1), 2-(4-methylbenzyl)-2-(dimethylamino)-1-(4-morpholinyl)-1-butanone (2-Dimethylamino-2-(4-methyl-benzyl)-1-(4-morpholin-4-yl-phenyl)-butan-1-one), 2-methyl-1-(4-methylthiobenzene) 2-Methyl-1-[4-(methylthio)phenyl]-2-morpholino-propane-1-one), 2-(ethyloxyiminomethyl) 2-(Acetyloxyiminomethyl)thioxanthene-9-one, 1-[4-(phenylthio)]-1,2-octanedione 2-(O-benzohydrazide) 1,2-octanedione, 1-[4-(phenylthio)-,2-(O-benzoyloxime)], 1-(9-ethyl-6-(2-methylbenzhydrazide)-9H-carbazole -3 -(6-ethyl-6-(2-methylbenzoyl)-9H-carbazole-3-yl)), ethyl ketone, 1-[9-ethyl-6-(2-methylbenzyl Ethyl, 1-(9-ethyl-6-(2-methylbenzoyl)-9H-carbazole-3-yl, Ethylene, 1-[9-ethyl-6-(2-methylbenzoyl)-9H-carbazole-3-yl 】-, 1-(O-acetyl oxime)), 4,4'-Bis(Dimethylamino)Benzophenone, 4,4'-double (two Ethyl benzophenone (4,4'-Bis (Diethylamino) Benzophenone) and the like. Further, specific examples of commercially available products include IRGACURE-369, -379, -907, -OXE01, -OXE02, and CGI-242 (manufactured by BASF JAPAN Co., Ltd.); N-1919 (manufactured by Adeka Co., Ltd.); and EAB (Zhongtu Valley Chemical Co., Ltd.) Company system) and so on.

The above (C) ultraviolet absorber may be used singly or in combination of two or more.

(C) the content of the ultraviolet absorber, with the heat of the present invention The solid content of the curable resin composition is preferably from 0.5 to 10% by mass, more preferably from 3 to 7% by mass based on the total solid content. When the ultraviolet absorber is less than 0.5% by mass, the laser processability may not be sufficiently improved. When it exceeds 10% by mass, the physical properties when it is used as the insulating resin layer may be lowered.

Further, as a component having ultraviolet absorbing property, when (A) a polyimine resin having a linear structure and (B) an epoxy resin having a polycyclic aromatic hydrocarbon ring are used in combination, the thermosetting resin of the present invention is used. The blending amount in the entire composition is a combination of (A) a polyimine resin having a linear structure and (B) an epoxy resin having a polycyclic aromatic hydrocarbon ring, which is thermally hardened with respect to the present invention. The resin composition has a mass ratio of 100 to 40 mass% to 99.5 mass ratio. When the blending amount is less than 40 by mass, the amount of the resin in the entire composition is low, so that it is difficult to control the fluidity of the composition, and the printability may be deteriorated. On the other hand, when the blending ratio exceeds 99.5 by mass, the amount of the inorganic filler or the like is relatively lowered, and the mechanical strength of the insulating resin layer may be lowered.

In addition, when only the (C) ultraviolet absorber is contained in the ultraviolet absorbing component, an epoxy resin, a phenol resin, an amine resin, an unsaturated polyester resin, or a polycarbamic acid can be used as the thermosetting resin component. A thermosetting resin which is conventionally used, such as an ethyl ester resin, a silicone resin, or a thermosetting polyimide resin.

The insulating resin layer using the above thermosetting resin composition preferably has a film thickness of 10 to 30 μm. When the film thickness is less than 10 μm, it is likely to be damaged by cracks or the like due to laser irradiation, which is not suitable. In addition, if When the film thickness exceeds 30 μm, the thickness as a substrate increases, and the thickness of the substrate cannot be reduced.

Further, a thermosetting resin composition of the present invention may further contain a conventionally used additive such as a thermosetting catalyst, an inorganic filler, a colorant, a thickener, an antifoaming agent, a leveling agent, and an adhesion imparting agent.

The above-mentioned thermosetting catalyst is used to further improve the thermosetting property of the thermosetting resin composition, and for example, an amine compound such as dicyandiamide or an aromatic amine, an imidazole, a phosphorus compound or an acid anhydride (Acid Anhydride) can be used. ), bicyclic amidine, and the like. Specifically, imidazole, 1-benzyl-2-phenylimidazole, 2-methylimidazole, 2-ethylimidazole, 2- 2-Ethyl-4-Methylimidazole, 2-Phenylimidazole, 4-Phenylimidazole, 1-cyanoethyl-2-phenyl Imidazoles such as 1-(Cyanoethyl-2-Phenylimidazole) and 1-(2-cyanoethyl)-2-ethyl-4-methylimidazole (1-(2-Cyanoethyl)-2-Ethyl-4-Methylimidazole) Class; dicyandiamide, Benzyldimethylamine, 4-(Dimethylamino)-N,N-Dimethylbenzylamine, 4-Methoxy-N,N-Dimethylbenzylamine, 4-Methyl-N,N-Dimethylbenzylamine An amine compound, a phosphorus compound such as triphenylphosphine, or the like. more Specifically, examples of the imidazole compound include 1B2PZ, 2E4MZ, 2MZ-A, 2MZ-OK, 2PHZ, and 2P4MHZ (manufactured by Shikoku Kasei Kogyo Co., Ltd.); and a blocked isocyanate compound as a dimethylamino group. There are U-CAT3503N and -3502T (manufactured by SAN-APRO Co., Ltd.), and DBU, DBN, U-CAT SA102, U-CAT5002 (manufactured by SAN-APRO Co., Ltd.), and the like. They may be used alone or in combination of two or more.

The content of the above-mentioned thermosetting catalyst is based on the general blending ratio For example, the mass ratio of the epoxy resin component to the thermosetting component is preferably from 0.1 to 10 mass%.

The above inorganic filler is used for suppressing the insulating resin layer Hardening shrinkage, improving adhesion, hardness and other characteristics. Examples of the inorganic filler include barium sulfate, barium titanate, amorphous austenite (Amorphous Silica), crystalline ceria (Crystalline Silica), molten ceria, spheroidal ceria, talc (Talc). , clay (Clay), magnesium carbonate, calcium carbonate, aluminum oxide, aluminum hydroxide, tantalum nitride, aluminum nitride, and the like. They may be used alone or in combination of two or more.

The above thermosetting resin composition is adjusted with an organic solvent After being suitable for the viscosity of the printing coating method, the printing is performed in a comprehensive manner so that the dried film thickness is preferably 10 μm to 30 μm. Next, the organic solvent contained in the composition is volatilized and dried at a temperature of 40 ° C to 100 ° C. Further, the insulating resin layer can be formed by heat-hardening at a temperature of 170 ° C to 230 ° C for 30 minutes to 120 minutes.

[Examples]

The invention is specifically illustrated by the following examples and comparative examples, but the invention is not limited thereto. In addition, the amount of each component is expressed as a quality standard, unless otherwise specified.

<Example 1> (Modulation of thermosetting resin composition)

Disposed separately: varnish 333 mass ratio, in which linear polyimide resin (V-8005.DIC company) is dissolved in dimethylacetamide to make the non-volatile component 15%; and varnish 167 mass ratio, wherein A lanthanide epoxy resin (YX-8800. manufactured by Mitsubishi Chemical Corporation) is dissolved in dimethylacetamide to make a nonvolatile component 30%; and 1-benzyl-2-phenylimidazole (1B2PZ. Industrial company system) 1 mass ratio; and 矽 oxygen-based surface tension adjuster (BYK-310.BYK company) 0.05 mass ratio; after mixing in the mixer, using a three roll mill to mix and heat Curable resin composition A.

According to the preparation of the thermosetting resin composition, the linear polyimide resin and the fluorene-based epoxy resin have high absorbability to the ultraviolet irradiation wavelength, and therefore, even if no ultraviolet absorber or the like is added, A thermosetting resin composition having high absorbency can be prepared.

(formation of insulating resin layer)

The thermosetting resin composition was applied to a copper foil laminated plate polished to a thickness of 0.8 mm by a polishing wheel, and 80 ° C in a hot air circulating drying oven. After drying for 30 minutes, it was hardened by heating at 230 ° C for 1 hour to form an insulating resin layer. At this time, the insulating resin layer on the substrate is leveled, and after the formation, the unevenness of the insulating resin layer will not be seen before the ultraviolet laser irradiation.

(groove forming engineering)

The ultraviolet ray laser (the third harmonic of the YVO ₄ laser, wavelength: 355 nm, pulse twist: 30 nanoseconds) is vertically irradiated on the insulating resin layer, and a part of the insulating resin layer at the irradiation portion is removed to form Wiring (ditch) for wiring.

(through hole forming engineering)

The ultraviolet ray laser (the third harmonic of the YVO ₄ laser, wavelength: 355 nm, pulse twist: 30 nanoseconds) is vertically irradiated on the insulating resin layer, and all of the insulating resin layer at the irradiation site is removed to make copper The metal layer of the foil laminate is exposed to form via holes for connecting the circuits.

[Dispersion Coating Engineering]

A dispersion containing a copper nanoparticle (average particle diameter of 100 nm) of 50% by weight (viscosity: 15 mPa.s) is used inside the trench formed by the above-described trench forming process and inside the via hole formed by the above-described through hole forming process. The entire area of the above-described trenches and via holes was filled by an ink jet printer (Sprint-8 (trade name) manufactured by ORBOTECH Co., Ltd.).

(burning treatment project)

After drying at 60 ° C for 30 minutes in a nitrogen atmosphere, the film was heated and baked at 200 ° C for 1 hour, thereby forming a copper wiring film inside the trench until the same height as the above-mentioned insulating resin layer, and forming a copper connection circuit inside the via hole. membrane.

<Example 2>

A test piece for forming a circuit pattern was produced in the same manner as in Example 1 except that the preparation of the thermosetting resin composition was changed as described below.

Dissolved separately: varnish 333 mass ratio, in which linear polyimide resin (V-8005.DIC company) is dissolved in dimethylacetamide to make non-volatile components 15%; and bisphenol A epoxy Resin (E828. manufactured by Mitsubishi Chemical Corporation) 50 mass ratio; and 1-benzyl-2-phenylimidazole (1B2PZ. manufactured by Shikoku Chemical Co., Ltd.) 1 mass ratio; and oxime surface tension adjuster (BYK-310) .BYK company) 0.05 mass ratio; after mixing in a mixer, it is kneaded by a three-cylinder kneader to prepare a thermosetting resin composition B.

By the preparation of the thermosetting resin composition B, since the linear polyimine resin is contained, even if the epoxy resin does not absorb light at the irradiation wavelength of the ultraviolet laser, heat having high absorption can be prepared. A curable resin composition.

<Example 3>

The preparation of the thermosetting resin composition is changed as follows, A test piece for forming a circuit pattern was produced in the same manner as in the above Example 1.

Each of the varnishes has a mass ratio of 100%, wherein a naphthalene epoxy resin (manufactured by EXA-4710.DIC) is dissolved in dimethylacetamide to make the nonvolatile content 50%; and a bisphenol A type epoxy resin ( E828.Mitsubishi Chemical Co., Ltd.) 50 mass ratio; and 1-benzyl-2-phenylimidazole (1B2PZ. Shikoku Chemical Co., Ltd.) 1 mass ratio; and oxime surface tension adjuster (BYK-310.BYK The company made a 0.05 mass ratio; after mixing with the mixer, it was mixed with a three-roller kneader to prepare a thermosetting resin composition C.

According to the preparation of the thermosetting resin composition C, since the naphthalene-based epoxy resin itself has high absorbability to the irradiation wavelength of the ultraviolet laser, it is possible to prepare a highly absorptive property without adding an ultraviolet absorber or the like. A thermosetting resin composition.

<Example 4>

A test piece for forming a circuit pattern was produced in the same manner as in Example 1 except that the preparation of the thermosetting resin composition was changed as described below.

Dispense separately: bisphenol A epoxy resin (E828. Mitsubishi Chemical Corporation) 50 mass ratio; and varnish 63 mass ratio, which will be tris-hydroxymethyl-methane epoxy resin (EPPH-501H. Made by Nippon Chemical Co., Ltd.) is dissolved in Propylene glycol monomethyl ether acetate to make it non-volatile 80% by mass; phenoxy resin (YX8100H30. manufactured by Mitsubishi Chemical Corporation) 67 mass ratio; and 1-benzyl-2-phenylimidazole (1B2PZ. Shikoku Chemical Co., Ltd.) 1 mass ratio; and varnish 62 mass a phenol phenol resin (HF-1M., manufactured by Minghe Chemical Co., Ltd.) dissolved in Diethylene glycol monoethyl ether to make the nonvolatile content 65%; and propylene glycol monomethyl ether acetate 30 mass ratio of ester (PGMAc. manufactured by Daisei Chemical Co., Ltd.); 15 mass ratio of benzophenone-based ultraviolet absorber (EAB. manufactured by Hodogaya Chemical Industry Co., Ltd.); and surface tension adjuster of 矽-based system (BYK-310. BYK company) 0.05 mass ratio; after mixing in a mixer, it was kneaded using a three-roller kneader to prepare a thermosetting resin composition D.

According to the preparation of the thermosetting resin composition D, even if the epoxy resin does not absorb light at the irradiation wavelength of the ultraviolet laser, since the benzophenone-based ultraviolet absorber is contained, heat having high absorption can be prepared. A curable resin composition.

<Comparative Example 1>

A test piece for forming a circuit pattern was produced in the same manner as in Example 1 except that the preparation of the thermosetting resin composition was changed as described below.

A benzophenone-based ultraviolet absorber (EAB. manufactured by Hodogaya Chemical Co., Ltd.) was removed from the composition of Example 4 to prepare a thermosetting resin composition E.

By the modulation of the above thermosetting resin composition E, a purple violet is prepared. The thermo-curable resin composition in which the irradiation wavelength of the external laser beam does not have absorption.

<Comparative Example 2>

A test piece for forming a circuit pattern was produced in the same manner as in the above-described Example 1, except that the groove forming process and the through hole forming process were changed as described below. (groove forming engineering)

The ultraviolet ray is irradiated perpendicularly to the insulating resin layer (the third harmonic of the YVO ₄ laser, the wavelength: 355 nm, the pulse twist: 20 pico-second), and a part of the insulating resin layer is removed, A trench (groove) for wiring is formed. (through hole forming engineering)

The ultraviolet ray laser (the third harmonic of the YVO ₄ laser, wavelength: 355 nm, pulse twist: 20 picoseconds) is vertically irradiated on the insulating resin layer, and all of the insulating resin layer is removed to laminate the copper foil. The metal layer of the board is exposed to form via holes for the connection circuit.

(Performance evaluation of test piece) (laser processing)

The number of ultraviolet laser irradiations at the time of forming the through holes was evaluated based on the following criteria.

Benchmark: the ratio of the diameter D of the through-hole diameter of the surface of the insulating resin layer to the through-hole diameter d of the surface of the copper foil laminated board (the bottom surface of the through-hole) (formula (d/D) × 100 [%]) required to exceed 70% . However, all of the insulating resin layers of the irradiated portion are removed without damaging the copper foil laminate. In addition, through hole straight The diameter system measures the length using a laser microscope.

◎: The number of irradiations is less than 30 times

○: The number of irradiations exceeds 30 times and is less than 40 times

△: The number of irradiations exceeds 40 times and is less than 100 times

×: The number of irradiations exceeded 100 times and the reference was still not reached.

The results are shown in Table 1 below. Further, the surface of the insulating resin layer formed by the number of irradiations of 40 or less had a through-hole diameter D of 30 μm.

(adhesion test)

In accordance with JIS H 8504 (coating adhesion test method, peel test method), a celluloid tape (trade name) is attached to the wiring film of the test piece and the connection circuit film on the copper foil laminate board, and then After the peeling test was carried out to perform a so-called pilling test, the peeling state of the wiring film and the connection circuit film was observed with an optical microscope, and evaluated according to the following criteria.

○: no peeling

△: Part of the wiring film and the connection circuit film are peeled off

×: Most of the wiring film and the connection circuit film are peeled off

The results are shown in Table 1 below.

As is clear from the results shown in Table 1, in Comparative Example 1, the insulating resin layer was inferior in laser workability. This is because the insulating resin layer does not have an absorption wavelength to the ultraviolet laser irradiation wavelength, and therefore cannot be processed and removed even if it is irradiated with an ultraviolet laser.

Next, in Comparative Example 2, the adhesion between the insulating resin layer and the wiring film, and the insulating resin layer and the connection circuit film was inferior. It is considered that this is because the ultraviolet ray having a pulse width of picoseconds is excellent in the smoothness of the inside of the formed groove and the through hole (the inner surface has extremely fine depressions, protrusions, and no hydrophilicity). The adhesion to the physical effect (fixation effect) is low.

In contrast, in the first to fourth embodiments, the laser processing property of the insulating resin layer is excellent in adhesion between the insulating resin layer and the wiring film, and between the insulating resin layer and the connection circuit film. It is considered that this is because the insulating resin layer has high absorption of the ultraviolet laser irradiation wavelength, so that the ultraviolet ray is irradiated, the insulating resin layer is processed and removed, and the wiring film or the connection circuit film is exposed; The ultraviolet light of the groove and the through hole formed by the ultraviolet pulse having the irradiation pulse intensity of nanosecond is poor (the inner surface has larger depressions, protrusions, and high hydrophilicity compared with the comparative example 2). The adhesion of the fixation effect is high. Further, in Examples 1 to 4, since the dispersion containing the metal nanoparticles was used in the formation of the circuit, the pre-plating treatment was omitted as shown in Fig. 2, and a fine circuit could be formed. Further, since the wiring film and the connection circuit film are formed in the entire region inside the trench and the via hole, it is possible to form a fine circuit without going through the polishing process as shown in FIG.

As described above, the circuit formation of the printed wiring board of the present invention In this way, a micro-circuit can be formed without a complicated pre-plating process that imposes a large burden on the environment, and a complicated process such as a polishing process of a metal film such as a plating film or a conductive coating film which is formed excessively. Moreover, when the circuit of the printed wiring board is formed, the processability of the laser irradiation with respect to the insulating resin layer and the adhesion of the insulating resin layer to the wiring film or the connection circuit film can be improved.

1‧‧‧metal foil laminate

1A‧‧‧Insulating resin layer

1B‧‧‧ metal layer

2A‧‧‧ trench

2B‧‧‧through hole

3‧‧‧Dispersion containing metal nanoparticles

4A‧‧‧ wiring film

4B‧‧‧Connected circuit film

5‧‧‧ spout nozzle

6‧‧‧UV laser

7‧‧‧ hatching

11‧‧‧ Electroless plating

Claims (7)

A circuit for forming a printed wiring board, comprising: a structure for forming a concave portion, which is an ultraviolet resin having an ultraviolet absorbing property on a metal foil laminated plate, and an ultraviolet laser having a pulse width of nanoseconds. The insulating resin layer is removed by irradiation to form a concave portion structure, and the dispersion coating process is performed, and a dispersion liquid containing metal nanoparticles is applied by an inkjet method inside a concave portion structure formed by the concave portion structure forming process. The circuit forming method of the printed wiring board according to the first aspect of the invention, wherein the concave portion structure is one or more of a groove and a through hole. The circuit forming method of the printed wiring board according to the first or second aspect of the invention, wherein the dispersion liquid is filled in the entire interior of the recess structure. The circuit forming method of the printed wiring board according to the first or second aspect of the invention, which has an electroless plating process after the dispersion coating process. A printed wiring board comprising the circuit obtained by the circuit forming method of the printed wiring board according to any one of claims 1 to 4. A thermosetting resin composition which is a thermosetting resin composition for forming an insulating resin layer in a circuit for forming a printed wiring board according to any one of claims 1 to 4, which is characterized in that: One or more of the following: (A) a polyimine resin having a linear structure, (B) an epoxy resin having a polycyclic aromatic hydrocarbon ring, and (C) an ultraviolet absorber. The thermosetting resin composition of claim 6, wherein the (B) epoxy resin having a polycyclic aromatic hydrocarbon ring is a naphthalene epoxy resin and an anthracene ring. One or more of oxygen resins.