KR20130142936A - Method for forming circuit of printed wiring board, thermosetting resin composition, and printed wiring board - Google Patents

Abstract

A method for forming a circuit of a printed wiring board, thermosetting resin composition, and a printed wiring board are provided, which is capable of forming a fine circuit without a need of a plating pre-processing process and a grinding process of metal excessively formed by a plating film or a conductive coating film and improving the processability of an insulating resin layer by laser irradiation or adhesion properties between the insulating resin layer and a circuit film. A method for forming a circuit of a printed wiring board comprises the steps of: a recess structure forming process for forming a recess structure by removing an insulating resin layer with the irradiation of ultraviolet laser with a pulse width of nanosecond for the insulating resin layer having ultraviolet absorption properties on a metal-clad laminate; and a disperse applying process for applying, by an inkjet method, disperse including metal nanoparticles to the inside of the recess structure formed by the recess structure forming process.

Description

TECHNICAL FOR FORMING CIRCUIT OF PRINTED WIRING BOARD, THERMOSETTING RESIN COMPOSITION, AND PRINTED WIRING BOARD}

The present invention does not require a plating pretreatment step with a large environmental load and a polishing step of an excessively formed metal film such as a plated film or a conductive coating film, so that a fine circuit can be formed, and the workability of the insulating resin layer by laser irradiation and insulation It relates to a circuit forming method of a printed wiring board, a thermosetting resin composition used therein, and a printed wiring board having good adhesion between the resin layer and the connection circuit film or the wiring film.

Generally, as a circuit formation method of a printed wiring board, there are a subtractive method, a full additive method, and a semi-additive method.

The subtractive method is a manufacturing method which forms a circuit by etching a metal foil over a resist. However, since circuit formation is controlled by etching liquid, it is not suitable for formation of a fine circuit. On the other hand, the full additive method or the semi-additive method is a manufacturing method for forming a circuit by electroless plating. However, in these circuit forming methods, the connection of the circuit part is affected by the unevenness of the insulating resin layer subjected to the roughening treatment. There is a problem that disconnection occurs, which is not suitable for forming a fine circuit.

In addition, as a fine circuit forming method that can comply with the recent demand for higher density and finer printed wiring boards, after the formation of trenches or via holes on the substrate surface using a laser or the like as described in Patent Documents 1 and 2, A method of forming a microcircuit inside a trench or via hole using electroless plating and electrolytic plating has been proposed.

Moreover, as a method of forming a microcircuit inside a trench or via hole, after passing through a plating pretreatment process as described in patent documents 3-5, it is called a catalyst layer or a plating nucleus inside a trench or via hole using the inkjet method. After forming a metal layer, the method of forming a microcircuit using electroless plating is proposed.

In addition, Patent Document 6 discloses a method of forming a fine circuit by filling a conductive paste into a trench or via hole inside using an inkjet method.

2 and 3 are schematic diagrams showing a conventional circuit forming method. Fig. 2 shows pretreatment of electroless plating with a pretreatment agent or a water repellent agent 9 after laser irradiation (Fig. 2 (c)), and the catalyst nucleus 10 is applied by an inkjet method to apply electroless plating. This is how to do it. In addition, in the method of FIG. 3, after forming a connection circuit film or a wiring film, grinding | polishing is performed by the grinding | polishing machine 8 for planarization.

Here, the conventional pretreatment of electroless plating refers to the process for selectively attaching plating, or the process for making it suitable for plating adhesion. In addition, a desmear process is not included in an electroless plating pretreatment process.

Japanese Patent Publication No. 2009-117415 U.S. Patent # 7312103 Japanese Patent Laid-Open No. 2011-151172 Japanese Patent Publication No. 2009-81212 Japanese Patent Publication No. 2010-21301 Japanese Patent Laid-Open No. 2004-152934

However, in the methods disclosed in Patent Documents 1 and 2 above, it is necessary to separately provide a polishing step (flattening step) by a CMP (Chemical Mechanical Polishing) method or the like in order to remove an excessively formed metal film after the plating step.

In addition, before the electroless plating process is carried out, the method disclosed in the above Patent Documents 3 to 5 undergoes a conventional plating pretreatment step or forms a so-called sacrificial layer such as a water-repellent resin layer on a portion that does not require a plating layer, or Should be.

In addition, the method disclosed in Patent Document 6 provides a polishing step (flattening step) using a buffing machine or a belt sander in order to remove the excessively formed conductive coating film after filling the conductive paste in the trench or via hole. There is a need. As described above, all of the methods proposed in the patent document go through a complicated process, resulting in a high manufacturing cost.

In addition, the circuit formation method of the printed wiring board which considered the laser workability at the time of forming a fine trench and a via hole recently, and the adhesiveness of the connection circuit film or wiring film after filling a electrically conductive paste, an insulating resin layer, a thermosetting resin composition, and Printed wiring boards are required.

Accordingly, an object of the present invention is to eliminate the need for a plating pretreatment step and a polishing step of an excessively formed metal film such as a plated film or a conductive coating film, so that a fine circuit can be formed, and the workability of the insulating resin layer by laser irradiation or insulation It is providing the circuit formation method of a printed wiring board with a favorable adhesiveness of a resin layer, a connection circuit film, or a wiring film, the thermosetting resin composition used for it, and a printed wiring board.

MEANS TO SOLVE THE PROBLEM As a result of earnestly examining in order to solve the said subject, the process of forming a recess structure in the insulated resin layer using a specific laser, and apply | coating the dispersion liquid containing metal nanoparticle inside the recess by the inkjet method is carried out. By setting it as the method provided, it discovered that the said subject could be solved, and came to complete this invention. It has also been found that certain thermosetting resin compositions are suitable for this method.

That is, the circuit formation method of the printed wiring board of this invention removes an insulated resin layer by irradiating the ultraviolet laser of a pulse width of nanosecond order with respect to the insulated resin layer which has ultraviolet absorbance on a metal-clad laminate, and forms a recess structure. And a dispersion liquid coating step of applying a dispersion liquid containing metal nanoparticles by an inkjet method to the inside of the recess structure formed by the recess structure forming step.

In the circuit formation method of the printed wiring board of this invention, it is preferable that the said recessed structure is any 1 or more types of a trench and a via hole.

Moreover, in the circuit formation method of the printed wiring board of this invention, it is preferable to fill the said whole liquid inside the said recessed structure in the said dispersion liquid application process.

Moreover, it is preferable that the circuit formation method of the printed wiring board of this invention has an electroless-plating process after the said dispersion liquid application | coating process.

The printed wiring board of this invention is equipped with the circuit obtained by the circuit formation method of any one of said printed wiring boards, It is characterized by the above-mentioned.

The thermosetting resin composition of this invention is a thermosetting resin composition used in order to form the insulated resin layer in the circuit formation method of any one of said printed wiring boards, (A) polyimide resin which has a linear structure, (B) polycyclic It is characterized by including any 1 or more types of epoxy resin which has aromatic hydrocarbon ring, and (C) ultraviolet absorber.

Moreover, in the thermosetting resin composition of this invention, it is preferable that the epoxy resin which has the said (B) polycyclic aromatic hydrocarbon ring is any 1 or more types of a naphthalene type epoxy resin and an anthracene type epoxy resin.

According to the present invention, a fine circuit can be formed without requiring the plating pretreatment step and the polishing step of the metal excessively formed by the plating film or the conductive coating film, and the processability of the insulating resin layer by laser irradiation, the insulating resin layer and It becomes possible to provide the circuit formation method of a printed wiring board in which the adhesiveness of a connection circuit film or a wiring film is favorable, the thermosetting resin composition used for it, and a printed wiring board.

BRIEF DESCRIPTION OF THE DRAWINGS It is a schematic diagram which shows the suitable example of the circuit formation method of the printed wiring board of this invention.
It is a schematic diagram which shows an example of the circuit formation method of the conventional printed wiring board.
It is a schematic diagram which shows an example of the circuit formation method of the conventional printed wiring board.

The circuit formation method of the printed wiring board of this invention comprises a recess structure formation process and a dispersion liquid application process, It is characterized by the above-mentioned. One suitable form of the circuit formation method of the printed wiring board of this invention is demonstrated using FIG. That is, by irradiating laser (FIG. 1 (a)), the recessed structure called trench 2A and via hole 2B is formed (FIG. 1 (b)), and the metal nanoparticle is formed by the inkjet method. The dispersion liquid containing (c11) or (c21) is apply | coated. When apply | coating the said dispersion liquid to a part of recess structure, Preferably, metal is laminated | stacked by electroless plating, and the inside of recess structure is filled or coated (FIG. 1 (c22)).

Suitably, after the dispersion is filled or after the electroless plating, the firing treatment is performed to bind the metal nanoparticles to form a connection circuit film or a wiring film (FIG. 1D).

Thereafter, the connection circuit film or the wiring film may be covered with an insulating layer (Fig. 1 (e)), or may be joined with gold bumps or solder bumps. Moreover, a laminated structure can also be formed by repeating the process similar to the above.

FIG.1 (f) is a schematic diagram which looked at the printed wiring board in which the circuit was formed by the method of this invention from the top. Hereinafter, each process is explained in full detail.

[Concave part structure formation process]

A recess structure formation process is a process of removing an insulation resin layer and forming a recess structure by irradiating the ultraviolet laser of a pulse width of nanosecond order with respect to the insulation resin layer which has ultraviolet absorbency on a metal-clad laminated board. That is, as shown in Fig. 1A, with respect to the metal-clad laminate having the insulating resin layer 1A and the metal layer 1B, an ultraviolet laser whose pulse width is nanosecond order from above the insulating resin layer 1A. Investigate. As a result, a recess structure as shown in Fig. 1B is formed. The recess is preferably any one or more of the trenches 2A and the via holes 2B. The formation of the trench 2A is performed by removing a part of the insulating resin layer 1A of the irradiation section of the ultraviolet laser, and the metal layer 1B is not exposed. The via hole 2B is formed by removing all of the insulating resin layer 1A of the irradiated portion of the ultraviolet laser and exposing the metal layer 1B.

(Ultraviolet laser)

The ultraviolet laser is a laser having an oscillation wavelength in the ultraviolet region (the wavelength from 200 nm to 400 nm), and in the present invention, the third harmonic laser (351 nm), YAG or YVO ₄ crystal, in which the YLF crystal is a medium, is a medium. It is especially preferable that it is a 3rd harmonic laser (355 nm).

As the irradiation method of the above-mentioned ultraviolet laser, there are pulse irradiation and continuous irradiation, but since the pulse irradiation has less damage such as thermal expansion and cracking of the insulating resin layer around the recess structure, the present invention is based on pulse irradiation. All. In addition, the repetition frequency of 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, since a long time is required for laser processing, it can lead to the fall of productivity. On the other hand, if it exceeds 500 kHz, in the case of nanosecond laser, the irradiation time per pulse is shortened, so that decomposition, vaporization, and heat storage of the insulating resin layer are likely to occur. There is a case. Moreover, as for the focal position of an ultraviolet laser, the surface of the insulated resin layer is preferable.

In the present invention, the pulse width of the ultraviolet laser is in nanosecond order. By using an ultraviolet laser having a pulse width of nanosecond order, the inner surface of the formed recess has an appropriate surface roughness, and is formed between the insulating resin layer and the wiring film or connection circuit film formed in the recess structure by the anchor effect. High adhesiveness is obtained. Preferred pulse widths are 1 to 100 ns, more preferably 1 to 50 ns.

The irradiation energy of the ultraviolet laser is expressed as irradiation energy [μJ / pulse] per pulse, and in the present invention, 0.5 μJ / pulse to 50 μJ / pulse is preferable, and more preferably 1 μJ / pulse to 10 μJ / pulse. In the case of irradiation, it shall be performed by the same irradiation energy. If the thickness is less than 0.5 µJ / pulse, since most of the insulating resin layer is not removed, it is difficult to form via holes and trenches, which is not preferable. On the other hand, when it exceeds 50 microJ / pulse, damage, such as a crack, may arise with respect to the base material after removing the insulating resin layer.

The number of irradiation of the ultraviolet laser needs to be performed until the desired concave structure can be formed, and the number of irradiation is proportional to the film thickness of the insulating resin layer. Specifically, in the case of forming the via hole, the number of times of irradiation of the laser required to remove the insulating resin layer having a film thickness of 10 to 20 µm and reach the metal layer is preferably 1 to 50 times. Further, the number of times of laser irradiation required to remove the insulating resin layer having a film thickness of 20 to 30 µm and form a via hole reaching the metal layer is preferably 1 to 100 times, more preferably 10 to 80 times. When too many irradiation times, the metal layer after removing the insulation resin layer may cause damage, such as a crack and removal. Similarly, when forming a trench, a laser is irradiated, moving at arbitrary processing feed rates and the number of irradiation spots. In addition, when forming a trench, since a part of insulation resin layer is removed, the thickness which is less than 10-20 micrometers or 20-30 micrometers in the case of forming a via hole is removed.

The shape of the recess structure formed by the ultraviolet laser is, in the case of the via hole, the ratio of the diameter D of the insulating resin layer surface to the diameter d of the metal layer surface (via hole bottom surface), that is, equation (d / D) × 100 It is expressed by [%]. In the case of the trench, the width d 'of the surface of the insulated resin layer and the width D' of the bottom of the insulated resin layer (the trench bottom) are similarly displayed. In the present invention, both the via hole and the trench are preferably 50% or more, and more preferably 70% or more. If it is less than 50%, the bottom of the via hole or the bottom of the trench may be too thin, which may cause a problem of poor adhesion between solder and metal plating. If the content exceeds 100%, the via hole and the trench become an inverted taper shape, which is not preferable.

The diameter of the via hole and the width of the trench formed by the ultraviolet laser are preferably 10 µm to 70 µm, more preferably 10 µm to 45 µm, in diameter D of the surface of the insulating resin layer. By using an ultraviolet laser, the printed wiring board corresponding to the narrow-pitch circuit wiring which cannot cope with the carbon dioxide laser used universally and the composition used for it, for example can be provided.

After the said ultraviolet laser irradiation, a desmear process can also be performed in order to decompose | disassemble and remove residual components, such as a processing residue after ultraviolet laser processing. The desmear process can employ | adopt all well-known methods, For example, the dry desmear method using the plasma generation apparatus under vacuum, and the wet desmear method using the chemical solution of desmear processes, such as a permanganate solution, are mentioned. have.

(Metal sheet laminate)

The said metal-clad laminated board has a structure in which the insulated resin layer was formed on the metal layer, for example as shown to 1 of FIG. The wiring layer is formed of the metal layer by the conductors, such as copper and silver, on a base material surface, Preferably it is a copper clad laminated board.

The base material of the said metal layer is not specifically limited if it is a base material used for a printed wiring board, For example, As a material, As a material, Paper phenol, Paper epoxy, Glass cloth epoxy, Glass polyimide, Glass cloth / nonwoven fabric epoxy, Glass cloth / paper epoxy, Synthetic fiber epoxy, aramid epoxy, polyimide resin, polyphenylene ether resin, bismaleimide-triazine resin, polyetherimide resin, fluorine, polyethylene, PPO, cyanate ester and the like, glass substrate, ceramic substrate, Wafer plate is mentioned.

(Insulation resin layer)

The said insulating resin layer is comprised by the insulating resin composition which has ultraviolet absorbency. By having ultraviolet absorbency, it can remove suitably by an ultraviolet laser and can form a recessed structure. Although the resin composition for forming an insulated resin layer may have ultraviolet absorbency and insulation, any of the thermosetting resin compositions of this invention as mentioned below is especially preferable.

[Dispersion application step]

A dispersion liquid application process is a process of apply | coating the dispersion liquid containing metal nanoparticle to the inside of the said recessed structure by the inkjet method. As shown in (c11) of FIG. 1, the whole inside of the recess structure may be filled with a dispersion liquid, and as shown in (c21) of FIG. You may apply it. The inkjet method may be either a piezo system or a bubble system, and is performed using a droplet ejection apparatus having a ejection head as shown in FIG. The inkjet droplet ejection apparatus relatively accurately positions the ejection head 5 on the desired concave structure by moving the ejection head 5 having the ejection nozzle ejecting droplets (dispersion liquid) and the metal-clad laminate. Then, a certain amount of droplets (dispersion liquid 3 containing metal nanoparticles) is discharged to reach the recess structure. As a result, the dispersion can be applied at any position by a desired amount. The desired amount means an amount to be filled in a whole or a part to be filled in the whole in which the insulated resin layer was removed according to the recessed structure formed by irradiating a laser. In addition, the volume resistance value of the metal layer (connection circuit film or wiring film) containing a metal nanoparticle at that time is 2-100 microohm * cm.

Moreover, after apply | coating a dispersion liquid, the process of drying can be provided, and a dispersion liquid can also be filled by repeating application | coating and drying. As the inkjet droplet discharging device, all of known ones can be used, and a commercially available device can also be used.

In order to apply the dispersion liquid containing a metal nanoparticle by the inkjet method, it is not necessary to etch away electroless plating and a catalyst, and it becomes possible to omit use of a plating resist.

(Dispersion)

The said dispersion liquid disperse | distributes metal nanoparticles in a solvent. Examples of the solvent include water, ketones, aromatic hydrocarbons, glycol ethers, glycol ether acetates, esters, alcohols, polyols, aliphatic hydrocarbons, petroleum solvents, and the like. More specifically, ketones such as methyl ethyl ketone and cyclohexanone; Aromatic hydrocarbons such as toluene, xylene, and tetramethylbenzene; Cellosolve, methyl cellosolve, butyl cellosolve, carbitol, methyl carbitol, butyl carbitol, propylene glycol monomethyl ether, dipropylene glycol monomethyl ether, dipropylene glycol diethyl ether, triethylene glycol monoethyl ether Glycol ethers such as these; Esters such as ethyl acetate, butyl acetate, dipropylene glycol methyl ether acetate, propylene glycol methyl ether acetate, propylene glycol ethyl ether acetate and propylene glycol butyl ether acetate; Stages such as ethanol, propanol, ethylene glycol, propylene glycol, butanediol, 1,3-butanediol, 1,4-butanediol, 2,3-butanediol, pentanediol, hexanediol, octanediol isobornylhexanol and terpineol Alcohols such as cyclic monoterpene alcohol; Aliphatic hydrocarbons such as octane and decane; Petroleum solvents such as petroleum ether, petroleum naphtha, hydrogenated petroleum naphtha, solvent naphtha and the like. These solvents may be used alone, or may be used as a mixture of two or more thereof.

Examples of the metal in the metal nanoparticles included in the dispersion include gold, silver, copper, palladium, tungsten, nickel, tantalum, bismuth, lead, indium, tin, titanium, aluminum and the like, alloys thereof, oxides thereof, Furthermore, indium tin oxide (ITO), indium oxide, or the like can be used. Especially, it is preferable to use copper and silver. The surface of the metal nanoparticles may also be treated with citrate salts such as sodium citrate and ammonium citrate, nitrogen compounds such as ammonium ions, quaternary ammonium compounds and amines.

It is preferable that the average particle diameter of a primary particle is 5-300 nm, It is more preferable that it is 10-200 nm, More preferably, the said metal nanoparticle (metal particle whose average particle diameter is nm order) is 10-100 nm. An average particle diameter can be calculated | required as an average of 100 metal particle | grains which observed the metal particle by the electron microscope like TEM and SEM and randomly extracted. When the average particle diameter of the metal particles is in the above range, i.e., nano size, the surface roughness of the electrode or wiring formed by coating or printing the dispersion and sintering can be lowered, and the firing temperature can be significantly lowered. It exhibits completely different properties from metal particles having a particle diameter (µm order).

The manufacturing method of a metal nanoparticle is not specifically limited, For example, any manufacturing method, such as a vapor phase synthesis method or a liquid phase reduction method, may be sufficient. As a commercial item of the silver particle which has said average particle diameter, silver nanoparticle dry powder-1, -2, -3, -4 etc. made from DOWA Electronics Co., Ltd. are mentioned. As a commercial item of a copper nanoparticle, the copper nanoparticle Cu-001 etc. made by IOX Corporation are mentioned.

Moreover, the said dispersion liquid may contain hydride microparticles | fine-particles of metals, such as copper, nickel, and palladium, as metal nanoparticle. Since hydride microparticles exist in the state which the metal atom and the hydrogen atom couple | bonded, it is harder to oxidize than the microparticles | fine-particles of metal itself in an air atmosphere. The metal hydride fine particles can be produced, for example, by the method described in Patent No. 4747839. That is, after dissolving the water-soluble compound of the metal in water and adjusting the pH to 3 or less, from the group consisting of amino group, amide group, sulfanyl group, sulfanediyl group, hydroxyl group, carboxyl group, carbonyl group and ether type oxy group It can manufacture by adding the organic compound and organic liquid which have one or more functional groups selected, and adding a reducing agent with stirring, and reducing the metal ion in aqueous solution.

1-85 mass% is preferable, and, as for the density | concentration of the metal nanoparticle in the said dispersion liquid, 10-50 mass% is more preferable. Moreover, 0.5-10000 mPa * s is preferable and, as for the viscosity (25 degreeC) of a dispersion liquid, 1-100 mPa * s is more preferable. The viscosity can be measured, for example, by a cone plate viscometer.

(Electroless plating process)

In the method of the present invention, when the dispersion is applied to a part of the recess structure in the dispersion liquid applying step, as shown in Figs. 1 (c21) and (c22), the inside of the recess structure is formed by electroless plating. It is preferable to coat or fill with metal. As described above, the dispersion liquid containing the metal nanoparticles applied to the inside of the recess structure by the inkjet method is dried, and the metal film after removing the solvent acts as a catalyst nucleus or starting point for electroless plating, and metals are laminated. . Examples of the electroless plating include electroless copper plating, electroless nickel plating, electroless nickel-tungsten alloy plating, electroless tin plating, and electroless gold plating. Electroless copper plating is preferable. Electroless plating can employ | adopt both a well-known method and a solution, and is not specifically limited. For example, as the electroless copper plating solution, one containing copper sulfate, EDTA, glyoxylic acid and sodium hydroxide and having a pH adjusted to 12.5 can be used. As the electroless nickel plating solution, for example, nickel sulfate, sodium hypophosphite, citrate and containing pH adjusted to 8-9 can be used. As the electroless plating method, the substrate may be immersed in the plating liquid under heating conditions, and preferably, the substrate is immersed in the plating liquid for 30 to 600 minutes under a temperature condition of 60 to 80 ° C. In addition, when immersing, it is preferable to stir the plating liquid.

(Baking process)

In the circuit formation method of the printed wiring board of this invention, Preferably, the base material is baked after a dispersion | distribution liquid application process or electroless plating, and metal nanoparticle is sintered and a wiring film or a connection circuit film is formed. It is preferable to perform baking for 5 to 60 minutes in 50-200 degreeC temperature conditions in air | atmosphere or nitrogen atmosphere. Moreover, it is preferable to perform a drying process and remove the solvent in a dispersion liquid before baking.

Thermosetting Resin Composition

The thermosetting resin composition of this invention is a thermosetting resin composition suitable for forming the insulated resin layer which has ultraviolet absorbency on the metal-clad laminated board used for the circuit formation method of above-mentioned this invention, (A) polyimide which has a linear structure It is characterized by including any 1 or more types of resin, (B) epoxy resin which has polycyclic aromatic hydrocarbon ring, and (C) ultraviolet absorber. Moreover, when including only (C) ultraviolet absorber as a component which has ultraviolet absorbency, it is necessary to include a thermosetting resin component in a thermosetting resin composition.

It is preferable that the polyimide resin which has the said (A) linear structure as a component which has ultraviolet absorbency is a linear structure, and contains cyclic imide bond in a resin skeleton. Moreover, an aromatic polyimide resin is preferable and, as for the polyimide resin which has a linear structure (A), it is preferable to be soluble in an organic solvent. Here, the aromatic polyimide resin is preferably a resin having a structural unit represented by the following general formula, and it is preferable to have a reactive functional group in the molecule. The position of the reactive functional group is not particularly limited, and may be terminal or central.

(Wherein R ₃ represents a tetravalent organic group having an aromatic ring, and R ₄ represents a divalent organic group having an aromatic ring, provided that when R ₃ has a reactive functional group, it is a pentavalent organic group and R ₄ is reactive) When having a functional group, it is a trivalent organic group)

(A) As a specific example of the polyimide resin which has a linear structure, V-8005 (made by DIC Corporation); GPI-NT, -HT (manufactured by Kagaku Kogyo Co., Ltd.); Rica coat SN-20, -PN-20, -CN-20 (made by Shin-Nippon Corporation) etc. are mentioned. These may be used individually by 1 type and may be used in combination of 2 or more type.

Moreover, as long as the polyimide resin which has the said (A) linear structure has ultraviolet absorbency, polyimide resins other than what was described in a specific example can also be used.

The content rate in the composition of the polyimide resin which has such a linear structure (A) is 10-90 mass% based on the total solid of the thermosetting resin composition of this invention, More preferably, it is 20-60 mass% to be. If the polyimide resin having the above-mentioned (A) linear structure is less than 10 mass%, heat resistance may fall, and the effect of this invention may not be exhibited, and when it exceeds 90 mass%, sclerosis | hardenability will become inadequate and a function as a cured coating film This may not be expressed.

The epoxy resin which has the said (B) polycyclic aromatic hydrocarbon ring as a component which has ultraviolet absorbency means the epoxy resin containing the polycyclic aromatic hydrocarbon ring which two or more aromatic rings condensed in the resin skeleton. Among the epoxy resins having these polycyclic aromatic hydrocarbon rings, in particular, naphthalene type epoxy resins or anthracene type epoxy resins having high water absorption in the ultraviolet region are preferable from the viewpoint of obtaining good ultraviolet laser workability.

As a specific example of the epoxy resin which has the said (B) polycyclic aromatic hydrocarbon ring, it is a naphthalene type epoxy resin, HP-4032, HP-4032D, HP-4700, HP-4710, HP-4770, EXA-4700, EXA-4710, EXA-7311 and EXA-9900 (all manufactured by DIC Corporation); ESN-175, ESN-355, ESN-375 (all manufactured by Shin-Nippon Setetsu Chemical Co., Ltd.); As an anthracene type epoxy resin, YX-8800 (made by Mitsubishi Chemical Corporation) etc. is mentioned. These may be used individually by 1 type and may be used in combination of 2 or more type.

(B) The content rate in the composition of the epoxy resin which has a polycyclic aromatic hydrocarbon ring is based on the total solid of the thermosetting resin composition of this invention, Preferably it is 10-90 mass%, More preferably, it is 20-60 mass% to be.

As said (C) ultraviolet absorber as a component which has ultraviolet absorbency, a benzophenone derivative, a benzoate derivative, a benzotriazole derivative, a triazine derivative, a benzothiazole derivative, a cinnamate derivative, an anthranilate derivative, a dibenzoylmethane derivative, etc. Can be mentioned. For example, 2-hydroxy-4-methoxybenzophenone, 2-hydroxy-4-n-octoxybenzophenone, 2,2'-dihydroxy-4-methoxybenzophenone, 2,4- Dihydroxybenzophenone, 2-ethylhexyl salicylate, phenyl salicylate, pt-butylphenyl salicylate, 2,4-di-t-butylphenyl-3,5-di-t-butyl-4- Hydroxybenzoate, hexadecyl-3,5-di-t-butyl-4-hydroxybenzoate, 2- (2'-hydroxy-5'-t-butylphenyl) benzotriazole, 2- (2 '-Hydroxy-5'-methylphenyl) benzotriazole, 2- (2'-hydroxy-3'-t-butyl-5'-methylphenyl) -5-chlorobenzotriazole, 2- (2'-hydroxy Hydroxy-3 ', 5'-di-t-butylphenyl) -5-chlorobenzotriazole, 2- (2'-hydroxy-5'-methylphenyl) benzotriazole, 2- (2'-hydroxy- 3 ', 5'-di-t-amyl phenyl) benzotriazole, hydroxyphenyl triazine, bisethylhexoxyoxy methoxy phenyl triazine, etc. are mentioned, As a specific example, CHIMASSORB 81 , TINUVIN 120, -NP, -234, -320, -32 6, -327, -328, -329, -1577ED (manufactured by BASF Japan); Smith Thorpe 200, -250, -300, -340, -350 (manufactured by Sumitomo Chemical Co., Ltd.); Adeka staff LA-31, -32, -36 (made by Adeka company) etc. are mentioned.

Moreover, as said (C) ultraviolet absorber, the photoinitiator generally used for photoresist can also be used. As such a photoinitiator, the (alpha)-aminoalkyl phenone compound, an acyl phosphine oxide compound, an oxime ester compound, a benzophenone compound, etc. are mentioned. As a specific example of a photoinitiator, it is 2-benzyl-2- dimethylamino-1- (4-morpholinophenyl) -butanone- 1, 2- dimethylamino-2- (4-methyl-benzyl) -1, for example. -(4-Morpholin-4-yl-phenyl) -butan-1-one, 2-methyl-1 [4- (methylthio) phenyl] -2-morpholinopropan-1-one, 2- (acetyl Oxyiminoethyl) thioxanthene-9-one, 1,2-octanedione, 1- [4- (phenylthio)-, 2- (O-benzoyloxime)], 1- (9-ethyl-6- ( 2-methylbenzoyl) -9H-carbazol-3-yl), ethanone, 1- [9-ethyl-6- (2-methylbenzoyl) -9H-carbazol-3-yl]-, 1- (O -Acetyl oxime), 4,4'-bis (dimethylamino) benzophenone, 4,4'-bis (diethylamino) benzophenone, etc. are mentioned. Moreover, as a specific example of a commercial item, Irgacure-369, -379, -907, -OXE01, -OXE02, CGI-242 (made by BASF Japan company); N-1919 (made by Adeca); EAB (made by Hodogaya Kagaku Co., Ltd.) etc. are mentioned.

Said (C) ultraviolet absorber may be used individually by 1 type, and may be used in combination of 2 or more type.

(C) The content rate of a ultraviolet absorber becomes like this. Preferably it is 0.5-10 mass%, More preferably, it is 3-7 mass% based on the total solid of the thermosetting resin composition of this invention. When the ultraviolet absorber is less than 0.5% by mass, the laser workability may not be sufficiently improved, and when it exceeds 10% by mass, the physical properties as the insulating resin layer may decrease.

In addition, when using together the epoxy resin which has the (A) polyimide resin which has a linear structure, and (B) polycyclic aromatic hydrocarbon ring as a component which has ultraviolet absorbency, the compounding quantity in the whole thermosetting resin composition of this invention is (A) It is preferable that they are 40 mass parts-99.5 mass parts with respect to 100 mass parts of thermosetting resin compositions of this invention with the total amount of the polyimide resin which has a linear structure, and the epoxy resin which has (B) polycyclic aromatic hydrocarbon ring. When the compounding quantity is less than 40 mass parts, since the amount of resin in the whole composition is low, control of the fluidity of a composition is difficult and printability may worsen. On the other hand, when a compounding ratio exceeds 99.5 mass parts, the compounding quantity, such as an inorganic filler, may fall comparatively and the mechanical strength of an insulated resin layer may fall.

In addition, when only the (C) ultraviolet absorber is included as a component which has ultraviolet absorbency, as a thermosetting resin component, an epoxy resin, a phenol resin, an amino resin, an unsaturated polyester resin, a polyurethane resin, a silicone resin, a thermosetting polyimide resin, etc. Known and commonly used thermosetting resins can be used.

It is preferable that the film thickness of the insulated resin layer using the said thermosetting resin composition is 10-30 micrometers. When the film thickness is less than 10 μm, damage to cracks or the like tends to be caused by laser irradiation, which is not preferable. Moreover, when the film thickness exceeds 30 micrometers, the thickness as a base material will increase and it cannot respond to thinning of a base material.

The thermosetting resin composition of this invention can further add well-known usual additives, such as a thermosetting catalyst, an inorganic filler, a coloring agent, a thickener, an antifoamer, a leveling agent, and an adhesive imparting agent.

The thermosetting catalyst is used in order to further improve the thermosetting properties of the thermosetting resin composition, for example, amine compounds such as dicyandiamide, aromatic amines, imidazoles, phosphorus compounds, acid anhydrides, bicyclic amidine compounds Etc. can be used. Specifically, imidazole, 1-benzyl-2-phenylimidazole, 2-methylimidazole, 2-ethylimidazole, 2-ethyl-4-methylimidazole, 2-phenylimidazole, Imidazoles such as 4-phenylimidazole, 1-cyanoethyl-2-phenylimidazole, and 1- (2-cyanoethyl) -2-ethyl-4-methylimidazole; Amines such as dicyandiamide, benzyldimethylamine, 4- (dimethylamino) -N, N-dimethylbenzylamine, 4-methoxy-N, N-dimethylbenzylamine, 4-methyl-N, N-dimethylbenzylamine Phosphorus compounds, such as a compound and a triphenyl phosphine, etc. can be used. More specifically, as an imidazole compound, 1B2PZ, 2E4MZ, 2MZ-A, 2MZ-OK, 2PHZ, 2P4MHZ (made by Shikoku Kasei Kogyo Co., Ltd.); As a block isocyanate compound of dimethylamine, it is U-CAT3503N, -3502T (made by the acid apros company); As a bicyclic amidine compound and its salt, DBU, DBN, U-CAT SA102, U-CAT5002 (made by acid-Apros), etc. are mentioned. These may be used individually by 1 type, or may be used in combination of 2 or more type.

The compounding rate of the said thermosetting catalyst is sufficient in a normal compounding ratio, For example, 0.1 mass part-10 mass parts are preferable with respect to 100 mass parts of epoxy resin components which are thermosetting components.

The said inorganic filler is used in order to suppress the cure shrinkage of an insulated resin layer, and to improve characteristics, such as adhesiveness and hardness. Examples of the inorganic fillers include barium sulfate, barium titanate, amorphous silica, crystalline silica, fused silica, spherical silica, talc, clay, magnesium carbonate, calcium carbonate, aluminum oxide, aluminum hydroxide, silicon nitride, aluminum nitride, and the like. Can be. These may be used individually by 1 type, or may be used in combination of 2 or more type.

After the said thermosetting resin composition is adjusted with the organic solvent at the viscosity suitable for the printing application method, it prints whole surface so that it may become 10 micrometers-30 micrometers preferably at a dry film thickness. Subsequently, the organic solvent contained in a composition is volatilized and dried at the temperature of 40 degreeC-100 degreeC. In addition, the insulating resin layer can be formed by heat curing at a temperature of 170 ° C to 230 ° C for 30 minutes to 120 minutes.

[Example]

Although an Example and a comparative example are shown to the following and this invention is demonstrated concretely, this invention is not limited to these. In addition, the value which shows the compounding quantity of each component is a mass reference | standard unless there is particular notice.

≪ Example 1 >

(Preparation of thermosetting resin composition)

333 parts of varnish melt | dissolved linear polyimide resin (made by V-8005, DIC Corporation) with dimethyl acetamide so that 15% of non volatile matters, and dimethyl so that anthracene type epoxy resin (YX-8800, Mitsubishi Chemical Corporation) make 30% of non volatile matters 167 parts of varnish dissolved in acetamide, 1 part of 1-benzyl-2-phenylimidazole (manufactured by 1B2PZ, Shikoku Kasei Kogyo Co., Ltd.), and 0.05 parts of silicon-based surface tension modifier (by BYK-310, Big Chemistry Co., Ltd.) were respectively blended. After the preliminary mixing, the mixture was kneaded using three roll mills to prepare a thermosetting resin composition A.

By producing the thermosetting resin composition, since the linear polyimide resin and the anthracene-type epoxy resin itself have high absorption with respect to the irradiation wavelength of the ultraviolet laser, the thermosetting resin composition having high absorption without the addition of an ultraviolet absorber or the like is obtained. Could be manufactured.

(Formation of Insulation Resin Layer)

The said thermosetting resin composition is apply | coated on the 0.8 mm-thick copper clad laminated board buff-roll-polished, and after drying for 30 minutes at 80 degreeC in a hot air circulation type drying furnace, it hardens by heating at 230 degreeC for 1 hour, and insulated resin layer Formed. At this time, the insulated resin layer on a base material is leveled, and the unevenness | corrugation of the insulated resin layer before ultraviolet laser irradiation shall not be seen.

(Trench Forming Step)

The trench for wiring by irradiating an ultraviolet laser (3 times harmonic of YVO ₄ laser, wavelength: 355 nm, pulse width: 30 nanoseconds) so that it may become perpendicular | vertical on the said insulated resin layer, and removing a part of the insulated resin layer of an irradiation site. (Home) formed.

(Via hole forming step)

Irradiating an ultraviolet laser (three times harmonic of YVO ₄ laser, wavelength: 355 nm, pulse width: 30 nanoseconds) so as to be perpendicular to the insulated resin layer, and removing all of the insulated resin layer at the irradiated point, the copper-clad laminate The via hole for a connection circuit was formed by exposing the metal layer of.

(Dispersion application step)

Inkjet printing machine (Orvo) using a dispersion liquid (viscosity 15 mPa · s) containing 50 wt% of copper nanoparticles (average particle diameter 100 nm) in the trench formed in the trench forming step and the via hole formed in the via hole forming step. Sprint-8 (trade name) manufactured by Tech Co., Ltd. was used to fill the entire regions of the trenches and via holes formed above.

(Baking process)

After drying for 30 minutes at 60 degreeC under nitrogen atmosphere, by heating and baking at 200 degreeC for 1 hour, the copper wiring film was formed in the trench up to the same height as the said insulated resin layer, and the copper connection circuit film was formed in the via hole.

<Example 2>

The test piece in which the circuit pattern was formed was produced by the method similar to the said Example 1 except having changed manufacture of a thermosetting resin composition as follows.

333 parts of varnish which melt | dissolved linear polyimide resin (made by V-8005, DIC Corporation) with dimethylacetamide so that it may be 15% of non volatile matter, 50 parts of bisphenol-A epoxy resin (made by E828, Mitsubishi Chemical Corporation), 1-benzyl-2- 1 part of phenylimidazole (manufactured by 1B2PZ, Shikoku Kasei Kogyo Co., Ltd.) and 0.05 parts of a silicone-based surface tension modifier (BYK-310, BIC Chemi Co., Ltd.) were respectively blended and premixed with a stirrer, followed by kneading using three roll mills. And the thermosetting resin composition B was manufactured.

By manufacturing the said thermosetting resin composition B, since the linear polyimide resin was included, even if the epoxy resin does not have absorption with respect to the irradiation wavelength of an ultraviolet laser, the thermosetting resin composition which has high absorption was able to be manufactured. .

<Example 3>

The test piece in which the circuit pattern was formed was produced by the method similar to the said Example 1 except having changed manufacture of a thermosetting resin composition as follows.

100 parts of varnish which melt | dissolved naphthalene type epoxy resin (made by EXA-4710, DIC Corporation) with dimethylacetamide so that it may be 50% of non volatile matter, 50 parts of bisphenol A type epoxy resin (made by E828, Mitsubishi Chemical Corporation), 1-benzyl-2- 1 part of phenylimidazole (manufactured by 1B2PZ, Shikoku Kasei Kogyo Co., Ltd.) and 0.05 parts of a silicone-based surface tension modifier (BYK-310, BIC Chemi Co., Ltd.) were respectively blended and premixed with a stirrer, followed by kneading using three roll mills. And the thermosetting resin composition C was manufactured.

By producing the thermosetting resin composition C, the naphthalene-type epoxy resin itself has a high absorption with respect to the irradiation wavelength of the ultraviolet laser, and thus a thermosetting resin composition having high absorption can be produced without adding an ultraviolet absorber or the like. .

<Example 4>

The test piece in which the circuit pattern was formed was produced by the method similar to the said Example 1 except having changed manufacture of a thermosetting resin composition as follows.

Varnish melt | dissolved 50 parts of bisphenol-A epoxy resin (made by E828, Mitsubishi Chemical Corporation), and trihydroxy phenylmethane type epoxy resin (made by EPPH-501H, Nippon Kayaku Co., Ltd.) with propylene glycol monomethyl ether acetate so that a non volatile matter may be 80%. 63 parts, phenoxy resin (YX8100H30, Mitsubishi Chemical Corporation) 67 parts, 1-benzyl-2-phenylimidazole (1B2PZ, Shikoku Kasei Kogyo Co., Ltd.) 1 part, phenol novolak resin (HF-1M, Meiwa) 62 parts of varnishes dissolved in diethylene glycol monoethyl ether, 30 parts of propylene glycol monomethyl ether acetate (manufactured by PGMAc and Daishin Kagaku Co., Ltd.) to a nonvolatile content of 65%, and a benzophenone ultraviolet absorber (EAB, Hodo) 15 parts of Kaya Kagaku Kogyo Co., Ltd., 0.05 parts of silicone surface tension modifier (BYK-310, Big Chemi Co., Ltd.) were respectively blended, and premixed with a stirrer, followed by kneading using three roll mills to form a thermosetting resin composition D. Manufactured.

By the production of the thermosetting resin composition D, even when the epoxy resin does not have absorption to the irradiation wavelength of the ultraviolet laser, it contains a benzophenone-based ultraviolet absorber, it was possible to produce a thermosetting resin composition having a high absorption.

&Lt; Comparative Example 1 &

The test piece in which the circuit pattern was formed was produced by the method similar to the said Example 1 except having changed manufacture of a thermosetting resin composition as follows.

The benzophenone ultraviolet absorber (EAB, Hodogaya Chemical Co., Ltd. make) was removed from the composition of Example 4, and the thermosetting resin composition E was manufactured.

By manufacture of the said thermosetting resin composition E, the thermosetting resin composition which does not have absorption with respect to the irradiation wavelength of an ultraviolet laser was manufactured.

Comparative Example 2

The test piece in which the circuit pattern was formed was produced by the method similar to the said Example 1 except having changed the trench formation process and the via hole formation process as follows.

(Trench Forming Step)

A trench for wiring (groove) by irradiating an ultraviolet laser (three times harmonic of YVO ₄ laser, wavelength: 355 nm, pulse width: 20 picoseconds) so as to be perpendicular to the insulating resin layer, and removing a part of the insulating resin layer. Formed).

(Via hole forming step)

An ultraviolet laser (three times harmonic of YVO ₄ laser, wavelength: 355 nm, pulse width: 20 picoseconds) is irradiated so as to be perpendicular to the insulating resin layer, and the entirety of the insulating resin layer is removed to remove the metal layer of the copper clad laminate. The via holes for the connection circuits were formed by exposing them.

(Performance Evaluation of Test Piece)

(Laser processability)

The following reference | standard evaluated the frequency | count of irradiation of the ultraviolet laser at the time of forming a via hole.

Reference: The ratio [formula (d / D) × 100 [%]] of the via hole diameter D of the insulating resin layer surface and the via hole diameter d of the copper clad laminate surface (via hole bottom face) is required to exceed 70%. To the number of surveys. However, all the insulated resin layers of the irradiated portion were removed so as not to damage the copper clad laminate. In addition, the diameter of the via hole was measured using the laser microscope.

(Double-circle): Number of irradiation times 30 or less

○: more than 30 survey times and 40 or less

(Triangle | delta): It exceeds 100 times and is 100 times or less

×: Even if the number of investigations is exceeded 100 times, it does not meet the standard

The results are shown in Table 1 below. In addition, the via-hole diameter D of the surface of the insulated resin layer formed in 40 times or less of irradiation times was 30 micrometers.

(Adhesion test)

Based on JIS H 8504 (Adhesion test method and peeling test method of plating), a cellophane tape (trade name) is affixed to the wiring film of a test piece and the connection circuit film on a copper clad laminated board, and after performing the peeling test which peels this, wiring is carried out. The peeling state of a film | membrane and a connection circuit film was observed with the optical microscope, and the following references | standards evaluated.

○: no peeling

(Triangle | delta): Peeling exists in a part of wiring film and connection circuit film

X: peeling exists in most of a wiring film and a connection circuit film

The results are shown in Table 1 below.

As apparent from the results shown in Table 1, in Comparative Example 1, the laser workability of the insulating resin layer was inferior. This is because the insulating resin layer does not have an absorption with respect to the irradiation wavelength of the ultraviolet laser, and thus is not removed even when irradiated with the ultraviolet laser.

Then, in the comparative example 2, the adhesiveness of the insulated resin layer, the wiring film, the insulated resin layer, and the connection circuit film was inferior. This was irradiated with an ultraviolet laser having a pulse width of picoseconds, and was excellent in smoothness in the formed trenches and via holes (having very fine recesses and protrusions on the inner surface and not having hydrophilicity), and thus the physical effect (anchor effect). It is considered that the adhesiveness due to this is low.

On the other hand, in Examples 1-4, the laser workability of the insulated resin layer and the adhesiveness of the insulated resin layer, the wiring film, the insulated resin layer, and the connection circuit film were excellent. This is because the insulating resin layer has high absorption with respect to the irradiation wavelength of the ultraviolet laser. Thus, the insulating resin layer is removed by irradiating an ultraviolet laser to expose the wiring film or the connection circuit film, and the ultraviolet laser having a pulse width of nanoseconds is irradiated. It is considered that the smoothness of the formed trenches and via holes is poor (having a larger recess and protrusion than that of Comparative Example 2 on the inner surface, and having high hydrophilicity) and high adhesion due to the anchor effect. In addition, in Examples 1-4, since the dispersion liquid containing metal nanoparticle was used when forming a circuit, the fine circuit was formed by omitting the plating pretreatment process like FIG. In addition, since the wiring film and the connection circuit film were formed in the entire region inside the trench and the via hole, it was possible to form a fine circuit without going through the polishing process as shown in FIG.

As mentioned above, the circuit formation method of the printed wiring board of this invention can form a fine circuit, without going through complicated processes, such as the plating pretreatment process with a large environmental load, and the grinding | polishing process of the excessively formed metal film, such as a plating film and an electroconductive coating film. Do. Furthermore, the circuit formation of the printed wiring board with the workability of the insulated resin layer by ultraviolet laser irradiation, and the adhesiveness of an insulated resin layer, a wiring film, or a connection circuit film is attained.

1: metal sheet laminate
1A: insulated resin layer
1B: metal layer
2A: trench
2B: Via Hole
3: dispersion containing metal nanoparticles
4A: wiring film
4B: connection circuit film
5: discharge head
6: ultraviolet laser
7: breaking line
8: grinding machine
9: pretreatment or water repellent
10: catalyst liquid (plating core)
11: electroless plating

Claims (7)

A recess structure forming step of forming an recess structure by removing the insulation resin layer by irradiating an ultraviolet laser having a pulse width of nanosecond order to the insulation resin layer having ultraviolet absorptivity on the metal sheet laminate;
Dispersion coating process of apply | coating the dispersion liquid containing metal nanoparticle to the inside of the recess structure formed by the said recess structure formation process by the inkjet method.
The circuit formation method of the printed wiring board which has a thing. The circuit forming method of a printed wiring board according to claim 1, wherein the recess structure is any one or more of a trench and a via hole. The circuit forming method of the printed wiring board according to claim 1 or 2, wherein in the dispersion liquid applying step, the dispersion liquid is filled in the entire inside of the recess structure. The circuit formation method of the printed wiring board of Claim 1 or 2 which has an electroless-plating process after the said dispersion liquid application | coating process. The circuit obtained by the circuit formation method of the printed wiring board of any one of Claims 1-4 is provided, The printed wiring board characterized by the above-mentioned. It is a thermosetting resin composition used in order to form the insulated resin layer in the circuit formation method of the printed wiring board of any one of Claims 1-4,
The thermosetting resin composition containing any one or more of (A) polyimide resin which has linear structure, (B) epoxy resin which has polycyclic aromatic hydrocarbon ring, and (C) ultraviolet absorber. The thermosetting resin composition according to claim 6, wherein the epoxy resin (B) having a polycyclic aromatic hydrocarbon ring is any one or more of a naphthalene type epoxy resin and an anthracene type epoxy resin.

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