WO2015186712A1 - Printed circuit board resin laminate for forming fine via hole, and multilayer printed circuit board having fine via hole in resin insulating layer and method for manufacturing same - Google Patents

Abstract

　Provided is a method for processing or manufacturing a printed circuit board in which it is possible to form a via hole in which the top diameter is reduced and the difference between the top diameter and the bottom diameter is smaller. Also provided is a resin laminate used in this method. A printed wiring board resin laminate including a resin insulating layer for forming a fine via hole and a release film for laser attenuation laminated on the resin insulating layer, wherein the thickness of the release film for laser attenuation is set to over 50 μm and no more than 180 μm, making it possible to form a via hole having a top diameter of 30 μm or less and a difference between the top diameter and the bottom diameter of 10 μm or less.

Description

Resin laminate for printed wiring board for forming fine via hole, multilayer printed wiring board having fine via hole in resin insulating layer, and manufacturing method thereof

The present invention relates to a resin laminate for a printed wiring board for forming a fine via hole, a multilayer printed wiring board having a fine via hole in a resin insulating layer, and a method for manufacturing the same.

In recent years, miniaturization and high performance of electronic devices have progressed, and in multilayer printed wiring boards, conductor wiring has been miniaturized in order to improve the mounting density of electronic components, and the wiring forming technology is desired. As a method of forming high-density fine wiring on the insulating layer, an additive method in which a conductor layer is formed only by electroless plating, or a conductor layer is formed by electrolytic plating after forming a thin copper layer on the entire surface by electroless plating. Then, a semi-additive method for flash-etching a thin copper layer after that is known.

The through holes and blind vias required for interlayer connection of printed wiring boards are formed by laser processing and drilling. As a method for forming a blind via by laser processing, a method using a UV-YAG laser and a method using a carbon dioxide gas laser are known. Although the UV-YAG laser has good processability for small-diameter holes, it is not always satisfactory from the viewpoint of cost and processing speed. On the other hand, although a carbon dioxide laser is excellent in terms of cost and processing speed, since the wavelength is long and the spot diameter is large, the workability of a small diameter hole is inferior to that of a UV-YAG laser having a short wavelength and a small spot diameter. In order to form a small-diameter blind via with a carbon dioxide laser, it is necessary to process with low processing energy. Therefore, the bottom diameter is smaller than the top diameter and the shape is more tapered, reducing the conduction reliability of the blind via. It becomes a factor.

Patent Documents 1 to 3 describe a method for producing a multilayer printed wiring board using an adhesive film, and Patent Document 1 uses a support base film having a release layer and an adhesive film made of a thermosetting resin composition. Then, a method of laminating the adhesive film on the core substrate and thermally curing it with the supporting base film attached, or with the supporting base film attached or after peeling is disclosed with a laser or drilling method. . Patent Document 2 discloses a method of laminating an insulating layer on one surface of a metal foil and further peeling a peelable organic film on the surface of the insulating layer, and laser processing from the organic film surface side. Further, in Patent Document 3, when forming a blind via using a carbon dioxide laser in an insulating layer containing a large amount of an inorganic filler, the top diameter and In order to form a blind via having a good hole formation with a small difference from the via bottom diameter, it is disclosed that a carbonic acid laser is used for an insulating layer on which a plastic film is laminated. Patent Documents 1 and 2 relate to the formation of a via hole having a top diameter of 100 μm or more, and Patent Document 3 describes that the top diameter is 100 μm or less, preferably 90 μm or less, and more preferably 80 μm or less. Therefore, these documents do not mention formation of fine via holes having a top diameter of 30 μm or less.

JP 2001-196743 A Japanese Patent No. 3899544 International Publication No. 2009/0666759

When forming a via hole in the resin insulation layer used for printed wiring boards, if the output energy of the carbon dioxide laser is reduced in order to reduce the diameter of the via hole, it becomes a shape with a strong taper from the top diameter to the bottom diameter. There is a problem that the difference between the diameter and the bottom diameter increases. Therefore, there is still a demand for a method of processing or manufacturing a printed wiring board capable of forming a via hole having a small difference between the top diameter and the bottom diameter while reducing the top diameter, and a resin laminate used in such a method.

The present inventors conducted extensive research on a method for forming a via hole having a small top diameter and a small difference between the top diameter and the bottom diameter with a laser (preferably a carbon dioxide gas laser). In addition, when the thickness of the release film for laser attenuation is set to be more than 50 μm to 180 μm or less, a fine via hole having a top diameter of 30 μm or less and a difference between the top diameter and the bottom diameter of 10 μm or less can be formed. The present invention has been reached.

Accordingly, the present invention relates to:
[1] A resin laminate for a printed wiring board comprising a resin insulation layer for forming fine via holes and a release film for laser attenuation laminated on the resin insulation layer, wherein the release film has a thickness of 50 μm A resin laminate having a thickness of 180 μm or less.
[2] The resin laminate according to item 1, wherein the release film for laser attenuation is formed of polyester.
[3] The polyester is selected from the group consisting of polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polybutylene naphthalate (PBN), polybutylene terephthalate (PBT), and polytrimethylene terephthalate (PTT). Item 3. The resin laminate according to Item 2, which is a seed or two or more.
[4] The method according to any one of Items 1 to 3, wherein a top diameter of the via hole formed in the resin insulating layer is 30 μm or less, and a difference between the top diameter and the bottom diameter is 10 μm or less.
[5] The resin laminate according to any one of items 1 to 4, wherein the resin insulating layer has a thickness of 3 to 50 μm.
[6] The resin laminate according to any one of items 1 to 5, wherein the resin insulating layer is formed from a thermosetting resin composition.
[7] The thermosetting resin composition comprises:
Epoxy resin;
Item 7. The resin laminate according to Item 6, comprising a cyanate ester compound; and an inorganic filler.
[8] The resin laminate according to item 6 or 7, wherein the thermosetting resin composition is semi-cured.
[9] The resin laminate according to any one of items 1 to 8, wherein the plating peel strength of the resin insulating layer is 0.4 kN / m or more.
[10] A method for producing a multilayer printed wiring board, comprising:
A circuit board having a base material and a conductive circuit formed on the base material, the resin laminate according to any one of items 1 to 9, and the conductive circuit of the circuit board and the resin laminate of the circuit board. Laminate so that the resin insulation layer faces,
Forming a via hole penetrating from the release film side for laser attenuation of the resin laminate to the resin insulation layer by a laser;
Peeling off the release film from the resin insulation layer.
[11] The resin laminate is the resin laminate according to item 8,
Item 11. The method according to Item 10, further comprising fully curing the resin insulation layer in a semi-cured state after the circuit board and the resin laminate are laminated and before forming the via hole.
[12] The method according to item 10 or 11, wherein the laser is a carbon dioxide laser.
[13] The method according to item 12, wherein the laser energy is 0.3 mJ to 5 mJ.
[14] The method according to any one of Items 10 to 13, wherein a top diameter of the via hole formed in the resin insulating layer is 30 μm or less, and a difference between the top diameter and the bottom diameter is 10 μm or less.
[15] Item 10 further comprising roughening the surface of the resin insulation layer after peeling off the release film, forming a conductor layer on the roughened surface by plating, and patterning the conductor layer to form a circuit. The method according to any one of 1 to 14.
[16] A multilayer printed wiring board obtained by the method according to any one of items 10 to 15.
[17] A circuit board having a base material and a conductive circuit formed on the base material, and a resin insulating layer of the resin laminate according to any one of items 1 to 9 laminated on the circuit board The resin insulating layer has a via hole formed by a laser, the top diameter of the via hole is 30 μm or less, and the difference between the top diameter and the bottom diameter is 10 μm or less. Multilayer printed wiring board.

For the resin laminate of the present invention, when an appropriate output energy is selected and a release film for laser attenuation is attached, a via hole is formed with a laser from the side of the release film. This release film can attenuate or cut off a low energy intensity laser. Thereby, a via hole having a small top diameter and a small difference between the top diameter and the bottom diameter can be formed in the resin insulating layer. Therefore, by laminating the resin laminate of the present invention on a circuit board and forming a via hole, a multilayer printed wiring board including a via hole having a small diameter and high conductivity reliability can be formed.

FIG. 1 is a schematic diagram showing a laser intensity distribution of a carbon dioxide laser. FIG. 2A shows a cross-sectional view of a resin plate after laser processing of a resin plate made of a resin insulating layer having a thickness of 20 μm. FIG. 2B shows a cross-sectional view of the resin laminate after laser processing from the release film side with respect to a resin laminate including a resin insulating layer having a thickness of 20 μm and a release film having a thickness of 100 μm.

One aspect of the present invention relates to a resin laminate for a printed wiring board including a resin insulating layer for forming fine via holes and a release film for laser attenuation laminated on the resin insulating layer. The mold film has a thickness of more than 50 μm and 180 μm or less.

The type of resin constituting the resin insulation layer in the resin laminate of the present invention is a resin used in the production of printed wiring boards, and a fine via hole is formed by using a laser (preferably a carbon dioxide laser). Any resin may be used as long as it is an insulating resin that can be formed. The size of the hole formed when using a laser is usually not greatly affected by the resin composition.

In the present invention, the fine via hole formed in the resin insulating layer refers to a via hole having a top diameter of 30 μm or less and a difference between the top diameter and the bottom diameter of 10 μm or less. From the viewpoint of enhancing the conductive reliability, the smaller the difference between the top diameter and the bottom diameter, the better. More preferably, it is 8 μm or less, and more preferably 5 μm or less. From the viewpoint of miniaturization of the conductor wiring, the top diameter is preferably as small as possible, for example, 30 μm or less, more preferably 27 μm or less, and further preferably 25 μm or less. On the other hand, from the viewpoint of improving the conductive reliability, the top diameter is usually preferably 15 μm or more.

The thickness of the resin insulating layer can be selected as long as the top diameter of the via hole and the difference between the top diameter and the bottom diameter of the via hole can be achieved. The upper limit of the thickness of the resin insulating layer is preferably 50 μm or less, more preferably 30 μm or less, and even more preferably 20 μm or less from the viewpoint of forming a via hole having a difference between the top diameter and the bottom diameter of 10 μm or less. . On the other hand, the lower limit of the thickness of the insulating layer is preferably 3 μm or more, more preferably 5 μm or more, and even more preferably 10 μm or more, from the viewpoint of insulation reliability of the insulating layer.

The size of via holes required for interlayer connection of printed wiring boards is desirably finer for miniaturization and higher density of wiring. In a printed wiring board using a fine via hole, it is required to miniaturize the wiring itself formed on the wiring board. Additive methods and semi-additive methods are well known as methods for forming high-density fine wiring. In these methods, fine wiring is formed by electroless plating or electrolytic plating. However, when the wiring is miniaturized, a contact area between the insulating layer and the wiring is reduced, which may cause a problem that the wiring is easily peeled off. Therefore, from the viewpoint of finer wiring and higher density, when forming a finer via hole, it is desirable that the resin insulating layer has higher plating peel strength.

In the production of a printed wiring board, the plating peel strength of the resin insulating layer is preferably 0.4 kN / m or more, more preferably 0.5 kN / m, from the viewpoint of preventing peeling of the plating formed on the resin insulating layer. m or more. The plating peel strength varies depending on the surface roughness of the resin insulating layer. The range of the plating peel described above may be any range of plating peel strength before or after the roughening treatment, but preferably means the range of plating peel strength after the roughening treatment.

[Release film]
Conventionally, a release film has been usually used to prevent adhesion to a pressurizing means when a resin insulating layer is laminated on a circuit board having a conductive circuit and heated and pressed. In this case, after the resin laminate is bonded to the circuit board, the release film is peeled off, the surface of the resin insulating layer is further roughened, and a conductor layer is formed on the roughened surface by plating. The conductor layer is patterned to form a circuit. On the other hand, in the embodiment of the present invention, the release film has a laser attenuation application in addition to the application of preventing adhesion to the pressing means.

In the present invention, laser attenuation refers to blocking or attenuating a low-intensity laser that is considered to cause a taper of the hole cross section of the resin insulating layer in the laser intensity distribution in the laser. The laser intensity distribution is usually a Gaussian distribution (FIG. 1). However, when passing through a mask (small hole) that reduces the beam diameter, light interferes and interference fringes occur. Even with a laser corresponding to such a low-intensity distribution including the interference fringes, a part of the resin insulating layer is scraped off, which may cause a taper (FIG. 2A). Therefore, the release film for laser attenuation according to the present invention is not intended to be limited to theory, but, for example, in the distribution of laser intensity, the laser with low intensity distribution including the interference fringe portion is attenuated or By blocking, the taper of the hole formed in the resin insulating layer can be minimized. The laser intensity to be blocked or attenuated varies depending on the thickness of the release film for laser attenuation, and those skilled in the art appropriately select the thickness of the release film for laser attenuation suitable for forming fine via holes. can do.

Although the release film for laser attenuation of the present invention is not intended to be limited to theory, it prevents the resin insulation layer from being excavated by a laser that is spread and distributed on the low intensity side of the laser intensity distribution. Thereby, the taper of the hole formed in the resin insulating layer can be reduced. Therefore, the release film for laser attenuation of the present invention is required to have a thickness sufficient to prevent excavation of the resin insulating layer by a low-intensity laser in the laser intensity distribution, From the standpoint of achieving the desired laser block or attenuation, it is preferably greater than 50 μm. More preferably, it is more than 60 μm, more preferably more than 70 μm. On the other hand, if the thickness is increased, it is necessary to increase the laser output for the formation of the through hole. In this case, it is not preferable because the top diameter of the hole becomes large. From this point, the thickness of the release film The upper limit of the thickness is 180 μm or less, more preferably 150 μm or less, and still more preferably 100 μm or less.

The release film for laser attenuation may be any film as long as it can attenuate the laser and peel off the resin insulating layer after heat curing. For example, polyester, polycarbonate (hereinafter abbreviated as “PC”). And acrylic resins such as polymethyl methacrylate (PMMA), cyclic polyolefin, triacetyl cellulose (TAC), polyether sulfide (PES), polyether ketone, polyimide, and the like. Among these, polyester is preferable, and polyethylene naphthalate (hereinafter sometimes abbreviated as “PEN”), polyethylene terephthalate (PET), polybutylene naphthalate (PBN), polybutylene terephthalate (PBT), and polytrimethylene terephthalate ( PTT) is preferred. Moreover, you may use the release film for laser attenuation | damping which contains laser absorptive components, such as black carbon. The release film may be provided with a release layer on the surface of the thermosetting resin composition layer so that the release film can be peeled after the thermosetting resin composition layer is heat-cured. Good. The release agent used for the release layer is not particularly limited as long as the release film can be peeled after the thermosetting resin composition layer is thermally cured. For example, a silicone release agent or an alkyd resin release agent is used. Examples include molds.

The resin laminate of the present invention can be produced by a method known to those skilled in the art. For example, a resin varnish in which a thermosetting resin composition is dissolved in an organic solvent is prepared. It can be produced by coating on a support film and drying the organic solvent by heating or blowing hot air to form a resin composition layer. Since the resin laminate is laminated on the circuit board and cured, the resin laminate is preferably in a semi-cured state.

[Resin insulation layer]
The resin used for the resin insulating layer of the present invention is not particularly limited as long as it is a resin used for an insulating layer of a printed wiring board, but is a thermosetting resin from the viewpoint of heat resistance, insulation, and plating adhesion. It is preferable.
Specific examples of the thermosetting resin include an epoxy resin, a cyanate ester resin, a bismaleimide resin, an imide resin, a phenol resin, a double bond-added polyphenylene ether resin, and an unsaturated polyester resin. One of these may be used alone, or two or more may be used in any combination and ratio.
Among these, from the viewpoint of providing a resin insulating layer having excellent peel strength, a mixture of an epoxy resin and a cyanate ester resin is preferable, and a bismaleimide resin is also preferably added.
In the resin composition used for the resin insulating layer of the present invention, for example, a curing agent is preferably used to cure the epoxy resin.
Moreover, when using a hardening | curing agent, in order to adjust a hardening rate suitably as needed, it is also possible to use a hardening accelerator together.
Furthermore, it is preferable that the resin composition used for the insulating layer of the present invention contains an inorganic filler from the viewpoint of low thermal expansion as long as desired characteristics are not impaired.

[Epoxy resin]
The epoxy resin used as the thermosetting resin of the resin insulating layer is not limited as long as it has two or more epoxy groups in one molecule, and any conventionally known epoxy resin can be used. Examples of epoxy resins include, for example, biphenyl aralkyl type epoxy resins, naphthalene tetrafunctional type epoxy resins, xylene type epoxy resins, naphthol aralkyl type epoxy resins, bisphenol A type epoxy resins, bisphenol F type epoxy resins, resins, bisphenol A novolaks. Type epoxy resin, trifunctional phenol type epoxy resin, tetrafunctional phenol type epoxy resin, naphthalene type epoxy resin, biphenyl type epoxy resin, aralkyl novolac type epoxy resin, alicyclic epoxy resin, polyol type epoxy resin, glycidylamine, glycidyl ester And a compound obtained by epoxidizing a double bond such as butadiene, a compound obtained by a reaction of a hydroxyl group-containing silicone resin and epichlorohydrin, and the like. Among these, biphenyl aralkyl type epoxy resins, naphthalene tetrafunctional type epoxy resins, xylene type epoxy resins, and naphthol aralkyl type epoxy resins are particularly preferable from the viewpoints of copper plating adhesion and flame retardancy. These epoxy resins can be used alone or in combination of two or more.

Examples of the biphenyl aralkyl type epoxy resin include those having a structure represented by the formula (1). Examples of the naphthalene tetrafunctional type epoxy resin include those having a structure represented by the formula (2). Examples of the type epoxy resin include those having a structure represented by Formula (3), and examples of the naphthol aralkyl type epoxy resin include those having a structure represented by Formula (4).

(In the formula, n1 represents an integer of 1 or more.)

(In the formula, n2 represents an integer of 1 or more.)

(N3 represents an average value of 1 to 6, X represents a glycidyl group or a hydrocarbon group having 1 to 8 carbon atoms, and the ratio of hydrocarbon group / glycidyl group is 0.05 to 2.0. )

The weight average molecular weight (Mw) of the epoxy resin is not limited, but from the viewpoint of developing the toughness of the cured resin, it is usually preferably 250 or more, and more preferably 300 or more. From the viewpoint of improving the heat resistance of the cured resin, it is usually 5000 or less, preferably 3000 or less.

The content of the epoxy compound in the resin composition used for the resin insulation layer of the present invention is not particularly limited, but in the range of 20 to 80% by mass of the resin solid content in the resin composition from the viewpoint of heat resistance and curability. The range of 30 to 70% by mass is particularly preferable.

[Maleimide compound]
As other components, a maleimide compound having a maleimide group, such as bis (4-maleimidophenyl) methane, 2,2-bis {4- (4-maleimidophenoxy) -phenyl} propane, bis (3,5-dimethyl- 4-maleimidophenyl) methane, bis (3-ethyl-5-methyl-4-maleimidophenyl) methane, bis (3,5-diethyl-4-maleimidophenyl) methane, and polyphenylmethanemaleimide constitute the resin insulation layer These maleimide compounds may be used in a resin composition and improve the moisture absorption heat resistance of the insulating layer. These maleimide compound prepolymers or maleimide compound and amine compound prepolymers can also be blended, and one or two or more of them can be used as appropriate.

[Curing agent]
The curing agent is not particularly limited as long as it is usually used as a curing agent for the above-described thermosetting resin. Examples include phenol compounds, polyphenol compounds, cyanate ester compounds, active ester compounds, dicyandiamide, carboxylic acid amides, amine compounds, various acid anhydrides, Lewis acid complexes, and the like. One of these may be used alone, or two or more may be used in any combination and ratio. When the curing agent is used, the use ratio is not limited. For example, it is usually 1 part by mass or more, especially 5 parts by mass or more, and usually 100 parts by mass of the resin solid content of the thermosetting resin. It is preferably 100 parts by mass or less, particularly 70 parts by mass or less. Moreover, although the use ratio of a thermosetting resin and a hardening | curing agent changes with kinds of thermosetting resin and a hardening | curing agent, for example, the reactive group (this is expressed as RF1) of a thermosetting resin, and this. The ratio (RF2 / RF1) to the number of reactive groups of the curing agent that reacts (this is expressed as RF2) is usually 0.3 or more, particularly 0.7 or more, and usually 3 or less, preferably 2.5 or less. It is preferable to use at such a ratio.

The cyanate ester compound used as a curing agent has excellent properties such as chemical resistance and adhesion, and because of its excellent chemical resistance, it is possible to form a uniform roughened surface. It can be suitably used as a component of the resin composition in the present invention. As the cyanate ester compound, generally known compounds can be used. For example, a naphthol aralkyl cyanate ester compound represented by the formula (5), a novolac cyanate ester represented by the formula (6), a formula (7) Biphenylaralkyl cyanate represented by the formula 1,3-dicyanatobenzene, 1,4-dicyanatobenzene, 1,3,5-tricyanatobenzene, bis (3,5-dimethyl4-cyanatophenyl) Methane, 1,3-dicyanatonaphthalene, 1,4-dicyanatonaphthalene, 1,6-dicyanatonaphthalene, 1,8-dicyanatonaphthalene, 2,6-dicyanatonaphthalene, 2,7-dicyanatonaphthalene, 1,3,6-tricyanatonaphthalene, 4,4'-dicyanatobiphenyl, bis (4-cyanatophenyl) methane, bis 4-cyanatophenyl) propane, bis (4-cyanatophenyl) ether, bis (4-cyanatophenyl) thioether, bis (4-cyanatophenyl) sulfone, 2,2′-bis (4-cyanatophenyl) ) Propane, bis (3,5-dimethyl, 4-cyanatophenyl) methane and the like.

Among these, the naphthol aralkyl cyanate ester compound represented by the formula (5), the novolak cyanate ester represented by the formula (6), and the biphenylaralkyl cyanate ester represented by the formula (7) are flame retardant. It is particularly preferable because of its excellent thermal resistance, high curability, and low thermal expansion coefficient of the cured product.

(In the formula, R1 represents a hydrogen atom or a methyl group, and n4 represents an integer of 1 or more.)

(In the formula, R2 represents a hydrogen atom or a methyl group, and n5 represents an integer of 1 or more.)

(In the formula, R3 represents a hydrogen atom or a methyl group, and n6 represents an integer of 1 or more.)

The active ester compound used as a curing agent has excellent characteristics such as low dielectric constant, low dielectric loss tangent, low water absorption, low thermal expansion coefficient, high glass transition temperature, etc., and excellent electrical characteristics and high glass transition temperature. Therefore, it can be suitably used as a component of the resin composition of the present invention. Generally known ones can be used, and preferred examples include Epicron HPC-8000 (DIC Corporation) and Epicron HPC-8000-65T (DIC Corporation).

[Inorganic filler]
An inorganic filler will not be specifically limited if it is normally used in this industry. Furthermore, one type or a plurality of types of inorganic fillers may be used. Examples of inorganic fillers include silicas such as magnesium hydroxide, magnesium oxide, natural silica, fused silica, amorphous silica, and hollow silica, molybdenum compounds such as boehmite, molybdenum oxide, and zinc molybdate, alumina, talc, and calcined talc. , Mica, short glass fiber, and spherical glass (glass fine powders such as E glass, T glass, and D glass).
In particular, from the viewpoint of providing a resin structure of a resin insulating layer having a preferable plating peel, an acid-soluble inorganic filler is preferable. By including an acid-soluble inorganic filler, a roughened surface with low roughness can be formed on the surface of the insulating layer, and a resin insulating layer having excellent plating adhesion when metal plating is formed on the roughened surface. Obtainable. This is not intended to be limited by theory, but the acid-soluble inorganic filler does not dissolve in the roughening step with the alkaline oxidant in the desmear treatment step, and is not dissolved in the acidic reducing agent. In addition to being dissolved in the summing step, when a cyanate ester compound is used, a resin structure having high chemical resistance can be provided, so that it is soluble in acid even in a roughening step with an alkaline oxidizing agent. This is because the inorganic filler does not fall off.

Examples of the acid-soluble inorganic filler used in the present invention include magnesium hydroxide and magnesium oxide. These are eluted in the neutralizing solution in the desmear treatment of the insulating layer surface, and have the effect of forming a uniform roughened surface and improving the plating peel strength. Specifically, as magnesium hydroxide, Echo Mag Z-10 and Echo Mug PZ-1 manufactured by Tateho Chemical Industry Co., Ltd., Magsees N, Magseeds S, Magseeds EP, Magseeds EP2-A manufactured by Kamishima Chemical Industry Co., Ltd. Examples thereof include MGZ-1, MGZ-3, MGZ-6R manufactured by Chemical Industry Co., Ltd., Kisuma 5, Kisuma 5A, Kisuma 5P manufactured by Kyowa Chemical Industry Co., Ltd., and the like. Examples of magnesium oxide include FNM-G manufactured by Tateho Chemical Industry Co., Ltd., SMO, SMO-0.1, SMO-S-0.5 manufactured by Sakai Chemical Industry Co., Ltd., and the like.

The average particle diameter of the acid-soluble inorganic filler is preferably 0.1 to 2.0 μm from the viewpoint of obtaining uniform surface roughness after desmear treatment. Here, the average particle diameter is the median diameter (median diameter). When the particle size distribution of the measured powder is divided into two, the number or mass on the large side and the mass on the small side are those of the whole powder. The particle diameter at 50% is generally measured by a wet laser diffraction / scattering method.

The content of the acid-soluble inorganic filler in the resin composition used for the resin insulating layer of the present invention is 5 to 150 parts by mass with respect to 100 parts by mass of the resin solid content in the resin composition. Is preferable from the viewpoint of the roughness of the surface of the insulating layer.

The acid-soluble inorganic filler is preferably surface-treated from the viewpoint of moisture absorption heat resistance and chemical resistance. Specifically, silane coupling treatment with a silane coupling agent, KBM-403 treatment, and KBM-3063 treatment are preferably performed.

The silane coupling agent is not particularly limited as long as it is a silane coupling agent generally used for surface treatment of inorganic substances. Specific examples include aminosilanes such as γ-aminopropyltriethoxysilane, N-β- (aminoethyl) -γ-aminopropyltrimethoxysilane, epoxysilanes such as γ-glycidoxypropyltrimethoxysilane, γ -Vinylsilanes such as methacryloxypropyltrimethoxysilane, cationic silanes such as N-β- (N-vinylbenzylaminoethyl) -γ-aminopropyltrimethoxysilane hydrochloride, phenylsilanes, etc. It is also possible to use one kind or a combination of two or more kinds as appropriate. The wetting dispersant is not particularly limited as long as it is a dispersion stabilizer used for coatings. For example, wetting and dispersing agents such as Disperbyk-110, 111, 180, 161, BYK-W996, W9010, W903 manufactured by Big Chemie Japan Co., Ltd. may be mentioned.

[Curing accelerator]
The curing accelerator is an optional component and is added to the resin composition in order to adjust the curing rate as necessary. These are not particularly limited as long as they are known and generally used as a curing accelerator for cyanate ester compounds and epoxy resins. Specific examples thereof include organic metal salts such as copper, zinc, cobalt and nickel, imidazoles and derivatives thereof, dimethylaminopyridine, tertiary amine and the like. One of these curing accelerators may be used alone, or two or more thereof may be used in any combination and ratio.

[Other ingredients]
The curable resin composition may contain other components without departing from the gist of the present invention. As other components, for example, other thermosetting resins, thermoplastic resins and oligomers thereof, various polymer compounds such as elastomers, other flame retardant compounds, additives and the like can be used in combination. These are not particularly limited as long as they are generally used. Examples of flame retardant compounds include phosphoric acid esters, melamine phosphates, phosphorus-containing epoxy resins, nitrogen compounds such as melamine and benzoguanamine, oxazine ring-containing compounds, silicone compounds, and the like. Additives include UV absorbers, antioxidants, photopolymerization initiators, optical brighteners, photosensitizers, dyes, pigments, thickeners, lubricants, antifoaming agents, dispersants, leveling agents, brighteners Etc., and can be used in appropriate combinations as desired.

Other components such as other thermosetting resins, thermoplastic resins and oligomers thereof, various polymer compounds such as elastomers, other flame retardant compounds, and additives can be used in combination. Furthermore, chopped strands or milled fibers such as glass fiber, carbon fiber, graphite fiber, aramid fiber, boron fiber, alumina fiber, silicon carbide fiber, antifoaming agent, rheology modifier, flame retardant, filler, polymerization inhibitor, pigment , Dyes, coupling agents, ion scavengers, release agents and the like. One of these other components may be used alone, or two or more thereof may be used in any combination and ratio.

[Use ratio of each component]
Although the usage ratio of each component at the time of manufacture of the resin laminated body of this invention is not limited, For example, it is as follows.

When the cyanate ester compound is used as the curing agent, the cyanate ester compound and the epoxy resin have a ratio of the cyanate group number of the cyanate ester compound to the number of epoxy groups of the epoxy resin (CN / Ep) of 0.7 to 0.7 in the resin composition. It is preferable to blend at 2.5. When CN / Ep is in the range of 0.7 to 2.5, good flame retardancy and curability can be obtained.

[Production method of resin structure]
The resin structure of the present invention is prepared by preparing a curable resin composition containing an epoxy resin, a curing agent, optionally an inorganic filler, optionally a curing accelerator, and optionally other components. The cured resin composition is cured to form a cured resin product, and then a surface roughening treatment is applied to at least one surface of the obtained cured resin product.

The method for preparing the curable resin composition is not limited, and it is possible to uniformly mix the epoxy resin, the curing agent, optionally the inorganic filler, optionally the curing accelerator, and optionally other components. Any method can be used as long as it is a simple method. Examples include the following.

(I) An epoxy resin is introduced into a reactor, and when the epoxy resin is solid, it is heated to an appropriate temperature to make it liquid, and optionally an inorganic filler is added and completely dissolved therein, and a curing agent and necessary are added there. A curable resin composition is prepared by adding a curing accelerator according to the above, uniformly mixing in a liquid state, and further defoaming treatment as necessary.
(Ii) Using a mixer or the like, after uniformly mixing the epoxy resin, curing agent, inorganic filler as necessary, and curing accelerator and other components added as necessary, heat roll, biaxial A method of preparing a curable resin composition by melt-kneading using an extruder, a kneader or the like.

(Iii) Epoxy resin, curing agent, inorganic filler as necessary, and curing accelerator and other components added as necessary are dissolved in a solvent such as methyl ethyl ketone, acetone, toluene, etc. to form a varnish. For preparing a conductive resin composition.

In addition, since a curing reaction starts when a curing agent is added to a mixture of an epoxy resin and an inorganic filler as necessary, the process after the addition of the curing agent is preferably performed as quickly as possible.

The method of curing the curable resin composition to form a cured resin product is not limited, and any conventionally selected curing method for the epoxy resin composition can be used. Examples of such a curing method include a thermal curing method, an energy beam curing method (electron beam curing method, ultraviolet curing method, etc.), a moisture curing method, and the like, and a thermal curing method is preferable.

Specifically, when the curable resin composition is solid at room temperature, for example, after pulverization and tableting, it is cured by a conventionally known molding method such as transfer molding, compression molding, injection molding, etc. A product (cured molded product) can be produced.

On the other hand, when the curable resin composition is liquid or varnished at room temperature, for example, the curable resin composition is poured into a mold (molding), poured into a container (potting, etc.), or applied onto a substrate. The resin cured product can be obtained by a method such as (lamination), impregnation into fibers (filaments) or the like (filament wiping or the like), followed by heat curing. In addition, the liquid or varnish-like curable resin composition at normal temperature may be cast, potted, contained, coated, impregnated into fibers, etc., if necessary, and then heated and dried to be in a semi-cured state When (B stage) is used, tackiness is reduced and workability can be improved. In addition, the curable resin composition of the present invention having a varnish shape is applied to a carrier film using a coating device such as a comma coater, a die coater, or a gravure coater, dried, and formed into a cured film shape. It can also be used, or it can be used after vacuum degassing.

The curing temperature and curing time for curing the curable resin composition may vary depending on the type of epoxy resin and curing agent, etc., for example, conditions of a curing temperature of 20 to 250 ° C., a curing time of 1 to 24 hours, etc. Is adopted.

[Protective film]
The resin laminate of the present invention may include a protective film laminated on the opposite side of the laser attenuation film on the resin insulating layer. The protective film protects the resin insulation layer from physical damage while preventing the adhesion of dust and debris during the flow of the resin laminate until it is laminated on the circuit board. can do. Examples of such a protective film include polyolefin films such as polyethylene, polypropylene, and polyvinyl chloride, polyester films such as PET and PEN, PC, and polyimide films. The protective film may be subjected to a mold release treatment in addition to the mud treatment and the corona treatment. The thickness of the protective film may be arbitrary, but is, for example, in the range of 5 to 30 μm. In order to distinguish from the release film for laser attenuation, the protective film may be colored or may be described as being a protective film.

[Method of manufacturing printed wiring board]
Another aspect of the present invention relates to a method for manufacturing a multilayer printed wiring board using the resin laminate of the present invention. In this method, the resin laminate of the present invention is placed on a circuit board having a base material and a conductive circuit formed on the base material, and the conductive circuit of the circuit board and the resin insulating layer of the resin laminate face each other. A step of laminating the layers. When a semi-cured resin laminate is used, a full curing step may be included after lamination. The operation of thermosetting the resin insulating layer made of a thermosetting resin can be performed according to a conventional method. For example, by laminating a resin laminate on one side or both sides of a circuit board so that the resin insulation layer and the circuit board face each other, using a metal plate such as a SUS end plate, heating and pressing, and performing a lamination press, It may be fully cured. The conditions at this time are generally used in this technical field and may be any conditions that can cure the thermosetting resin. For example, the pressure is 5 to 40 kgf / cm ² , the temperature is 120 to 180 ° C., and the time is 20 to 100 minutes. The press time can be performed. Heating and pressurization can be performed by pressing a heated metal plate such as a SUS mirror plate from the plastic film side. However, instead of directly pressing the metal plate, an adhesive sheet is sufficient for circuit irregularities on the circuit board. It is preferable to press through an elastic material such as heat-resistant rubber so as to follow. The lamination step can also be performed using a vacuum laminator. In this case, the resin laminate is heated and pressurized under reduced pressure to laminate the resin laminate on the circuit board. The lamination conditions may be those generally used in the field, for example, a temperature of 70 to 140 ° C., a pressure in the range of 1 to 11 kgf / cm ² , and a reduced pressure of 20 mmHg (26.7 hPa) or less. Is called. After the laminating step, the laminated adhesive film may be smoothed by hot pressing with a metal plate. The laminating step and the smoothing step can be continuously performed by a commercially available vacuum laminator. A thermosetting step can be performed after the laminating step or after the smoothing step. In the thermosetting step, the resin composition is thermoset to form an insulating layer. The thermosetting conditions vary depending on the type of thermosetting resin composition, but generally the curing temperature is 170 to 190 ° C. and the curing time is 15 to 60 minutes.

The method for producing a multilayer printed wiring board of the present invention further includes a step of irradiating the laminated circuit board and the resin laminate with a laser from the release film side for laser attenuation of the resin laminate. By laser irradiation, fine via holes that penetrate the resin insulating layer can be formed. As for the size of the fine via hole, the top diameter of the via hole is preferably 30 μm or less, and the difference between the top diameter and the bottom diameter is 10 μm or less.

The kind of laser to irradiate is not limited. Examples include a carbon dioxide laser, a YAG laser, and an excimer laser. Of these, a carbon dioxide laser is preferred.
As the carbon dioxide laser to be irradiated, a laser having a wavelength of 9.2 to 10.8 μm is generally used. In addition, the number of shots may be performed once or a plurality of times. However, in order to exert the laser attenuation effect of the release film for laser attenuation, the number of shots is preferably one and even when it is performed a plurality of times. The second and subsequent times are preferably cleaning shots with reduced output. Those skilled in the art can appropriately set the output energy of the carbon dioxide laser according to the thickness of the resin insulating layer, the thickness of the release film for laser attenuation, and the desired hole diameter. Usually, the greater the thickness of the resin insulation layer and the thickness of the release film for laser attenuation, the higher the required output energy of the carbon dioxide laser. On the other hand, if the energy of the carbon dioxide laser is too low, the bottom diameter is smaller than the top diameter and the shape is strongly tapered due to a decrease in workability. Accordingly, from the viewpoint of using a laser attenuating release film having a thickness of more than 50 μm and / or a difference between the top diameter and the bottom diameter of 10 μm or less, the output energy is, for example, 0.3 mJ or more, particularly more than 0.6 mJ. , Preferably 0.8 mJ or more. On the other hand, from the viewpoint of suppressing the top diameter to 30 μm or less, the output energy is 5 mJ or less, more preferably 3 mJ or less. The pulse width of the carbon dioxide laser is not particularly limited and can be selected in a wide range from a pulse of about 0.5 μs to 100 μs. From the viewpoint of suppressing the top diameter to 30 μm or less, the upper limit is preferably 30 μs or less, more preferably 15 μs or less.

The method for producing the multilayer printed wiring board of the present invention may further include a step of peeling the release film from the resin layer after forming the via hole by laser irradiation. After peeling off the release film, a roughening treatment step for roughening the surface of the resin insulating layer may be performed. The method of the surface roughening treatment is not limited, and may be appropriately selected according to the type of the epoxy resin and, if necessary, the inorganic filler, and examples include ultraviolet irradiation treatment, plasma treatment, and solvent treatment. Any one of these may be applied alone, or two or more thereof may be applied in any combination.

The ultraviolet irradiation treatment is performed by irradiating the surface of the cured resin with ultraviolet rays. The wavelength of the ultraviolet light is not limited, but is usually 20 nm or more, preferably 50 nm or more, more preferably 100 nm or more, and usually 400 nm or less, preferably 350 nm or less, and more preferably 300 nm or less. Although the irradiation time of ultraviolet rays is not limited, it is usually 2 minutes or more, preferably 5 minutes or more, and usually 240 minutes or less, preferably 120 minutes or less.

The plasma treatment is performed by irradiating the surface of the cured resin with plasma. The kind of plasma is arbitrary. Examples include plasmas of oxygen (oxygen plasma), argon (argon plasma), air (air plasma), nitrogen (nitrogen plasma), and the like. Any of these may be used alone, or two or more of these may be used in any combination and ratio. Although the plasma irradiation time is not limited, it is usually 2 minutes or more, preferably 5 minutes or more, and usually 240 minutes or less, preferably 120 minutes or less.

Examples of the solvent treatment include, but are not limited to, an oxidation treatment with an acidic solvent and a reduction treatment with an alkaline solvent. Especially, as a solvent process, it is preferable to implement the solvent process which consists of a swelling process, a surface roughening and smear melt | dissolution process, and a neutralization process.

The swelling step is performed by swelling the surface insulating layer using a swelling agent. The swelling agent is not limited as long as the wettability of the surface insulating layer is improved and the surface insulating layer can be swollen to the extent that oxidative decomposition is promoted in the next surface roughening and smear dissolving step. . Examples include alkaline solutions and surfactant solutions.

The surface roughening and smear dissolution process is performed using an oxidizing agent. As an oxidizing agent, a permanganate solution etc. are mentioned, for example, A potassium permanganate aqueous solution, a sodium permanganate aqueous solution, etc. are mentioned as a suitable specific example. Such oxidant treatment is called wet desmear, but in addition to the wet desmear, other known roughening treatments such as dry desmear by plasma treatment or UV treatment, mechanical polishing by buffing, sandblasting, etc. are carried out in an appropriate combination May be.

In the neutralization step, the oxidizing agent used in the previous step is neutralized with a reducing agent. Examples of the reducing agent include amine-based reducing agents, and preferred specific examples include acidic reducing agents such as hydroxylamine sulfate aqueous solution, ethylenediaminetetraacetic acid aqueous solution, and nitrilotriacetic acid aqueous solution.

The method for producing a multilayer printed wiring board according to the present invention includes a plating step of forming a conductor layer by plating on the surface of a resin insulating layer after or without roughening, and a circuit on the formed conductor layer. A circuit forming (patterning) step for forming the pattern may be further included. These steps can be performed according to various conventionally known methods used in the production of multilayer printed wiring boards.

The plating process is performed by, for example, forming a conductor layer by a method combining electroless plating and electrolytic plating on the surface of the insulating layer on which irregularities are formed by roughening treatment, or forming the conductor layer only by electroless plating. Is called. The conductor layer can be formed of a metal such as copper, aluminum, nickel, silver, or gold, or an alloy of these metals, but copper is particularly preferable. The copper plating layer can be formed by a method combining electroless copper plating and electrolytic copper plating, or by forming a plating resist having a pattern opposite to that of the conductor layer, and forming the conductor layer only by electroless copper plating.

Examples of the circuit forming process include a semi-additive method, a full additive method, a subtractive method, and the like. Among these, the semi-additive method is preferable from the viewpoint of forming a fine wiring pattern.

As an example of the pattern forming method by the semi-additive method, after forming a thin conductor layer on the surface of the insulating layer by electroless plating, etc., electrolytic plating is selectively performed using a plating resist (pattern plating), and then the plating resist And a method of forming a wiring pattern by etching an appropriate amount of the whole.

As an example of a method of forming a pattern by a full additive method, there is a method of forming a wiring pattern by performing pattern formation in advance using a plating resist on the surface of an insulating layer and selectively attaching electroless plating or the like.

An example of a pattern forming method using the subtractive method is a method of forming a wiring pattern by forming a conductive layer on the surface of an insulating layer by plating and then selectively removing the conductive layer using an etching resist. It is done.

When forming a wiring pattern by plating, it is preferable to perform a drying step after plating from the viewpoint of improving the adhesion strength between the insulating layer and the conductor layer. The pattern formation by the semi-additive method is performed by combining electroless plating and electrolytic plating. In this case, it is preferable to perform drying after the electroless plating and after the electrolytic plating. The drying after electroless is preferably performed at 80 to 180 ° C. for 10 to 120 minutes, for example, and the drying after the electroplating is preferably performed at 130 to 220 ° C. for 10 to 120 minutes, for example.

The circuit board used for the production of the multilayer printed wiring board of the present invention is mainly a pattern on one or both sides of a substrate such as a glass epoxy substrate, a metal substrate, a polyester substrate, a polyimide substrate, a BT resin substrate, a thermosetting polyphenylene ether substrate, etc. This means that a processed conductor layer (circuit) is formed. Further, when the multilayer printed wiring board is manufactured, an inner layer circuit board of an intermediate product in which an insulating layer and / or a conductor layer is further formed is also included in the circuit board referred to in the present invention. The surface of the conductor layer (circuit) is preferably subjected to a roughening treatment in advance by a blackening treatment or the like from the viewpoint of adhesion of the insulating layer to the circuit board.

[Production of cyanate ester compounds]
Synthesis Example 1 Synthesis of α-naphthol aralkyl cyanate ester compound (compound of formula (8)):

(In the formula, the average value of n is 3 to 4.)

A reactor equipped with a thermometer, a stirrer, a dropping funnel and a reflux condenser was previously cooled to 0 to 5 ° C. with a saline solution, to which 7.47 g (0.122 mol) of cyanogen chloride and 35% hydrochloric acid 9. 75 g (0.0935 mol), 76 ml of water, and 44 ml of methylene chloride were charged.

The α-naphthol aralkyl resin (SN485, OH group equivalent: 214 g / eq.) Represented by the following formula (8 ′) is stirred with the temperature in the reactor kept at −5 to + 5 ° C. and the pH at 1 or less. Softening point: 86 ° C., Nippon Steel Chemical Co., Ltd. 20 g (0.0935 mol) and triethylamine 14.16 g (0.14 mol) dissolved in 92 ml of methylene chloride were added dropwise over 1 hour using a dropping funnel. After completion of the dropwise addition, 4.72 g (0.047 mol) of triethylamine was further added dropwise over 15 minutes.

(In the formula, the average value of n is 3 to 4.)

After completion of the dropping, the reaction solution was separated after stirring at the same temperature for 15 minutes, and the organic layer was separated. The obtained organic layer was washed twice with 100 ml of water, and then methylene chloride was distilled off under reduced pressure using an evaporator. Finally, the mixture was concentrated to dryness at 80 ° C. for 1 hour, and expressed by the above formula (8). 23.5 g of a cyanate ester compound (α-naphthol aralkyl type cyanate ester compound) of α-naphthol aralkyl resin was obtained.

[Preparation of resin composition]
As epoxy resin, 47.5 parts by mass of biphenyl aralkyl type epoxy resin represented by the formula (1) (NC-3000-H, manufactured by Nippon Kayaku Co., Ltd.), and as the second epoxy resin, naphthalene type epoxy resin (HP4710, manufactured by DIC Corporation) 12.7 parts by mass, as a cyanate ester compound, α-naphthol aralkyl-type cyanate ester compound represented by the formula (8) obtained by Synthesis Example 1 (cyanate equivalent: 261 g) / Eq.) Methyl ethyl ketone (hereinafter sometimes abbreviated as “MEK”) solution (non-volatile content: 50 mass%) 51.4 parts by mass (25.7 parts by mass in terms of non-volatile content), maleimide compound represented by formula (9 11.1 parts by weight of a maleimide compound (BMI-2300, manufactured by Daiwa Kasei Co., Ltd.), 2,4,5-triphenyl as a curing accelerator 300 parts by mass of PMA solution (non-volatile content 1% by mass) of midazole (manufactured by Wako Pure Chemical Industries, Ltd.) (3.0% by mass in terms of non-volatile content) and 7 parts by mass of MEK solution of zinc octylate (non-volatile content 1% by mass) 0.07 parts by mass in terms of minutes) was dissolved or dispersed in MEK. Further, 125 parts by mass of magnesium oxide (SMO-0.4, manufactured by Sakai Chemical Industry Co., Ltd., average particle size 0.4 μm) was added as an inorganic filler, and the mixture was stirred for 30 minutes using a high-speed stirring device. A varnish (a solution of a resin composition containing an epoxy resin, a cyanate ester resin, a maleimide compound, and an inorganic filler) was obtained.

(Wherein R ^{1 to 4} each independently represent a hydrogen atom or a methyl group, and n is in the range of 1 to 10 as an average value.)

[Create resin laminate]
The obtained varnish was uniformly applied to the release surface of the PET film with a release layer with a die coater so that the thickness of the resin composition layer after drying was 8 μm or 20 μm, and was applied at 150 to 180 ° C. 3 Dried for minutes. Subsequently, it wound up in roll shape, bonding a 15-micrometer-thick polypropylene film on the surface of a resin composition layer. The roll-like adhesive film was slit to a width of 507 mm to obtain a sheet-like adhesive film having a size of 507 × 336 mm.

[Formation of via hole in resin insulation layer]
Adhesive film was temporarily attached to both sides of a copper-clad laminate with a circuit formation (circuit conductor thickness 18 μm) of 510 × 340 mm size and thickness 0.2 mm, and a temperature of 130 ° C. by a vacuum laminator manufactured by Nichigo Morton Co., Ltd. Lamination was performed on both surfaces under the conditions of a pressure of 10 kgf / cm ² and an atmospheric pressure of 5 mmHg or less, and further, hot pressing with a SUS end plate was performed under the conditions of a temperature of 180 ° C. and a pressure of 10 kgf / cm ² . Next, the film was thermally cured at 180 ° C. for 30 minutes with a PET film with a release layer attached, and insulating layers were formed on both sides of the circuit board. After cooling to room temperature, the PET film with a release layer was not peeled off, and a hole was drilled from above using a carbon dioxide laser device (ML605GTWIII-H-5200U) manufactured by Mitsubishi Electric Corporation, and blind vias (top diameter 20-30 μm) Assumed). In addition, in order to set the assumed top diameter to 20 to 30 μm, a mask diameter of 0.6 mm was used for drilling in the state where the PET film with a release layer of this example was adhered.

Example 1: Use of PET film with release layer having a total thickness of 75 μm As a release film for laser attenuation, a PET film with a release layer having a total thickness of 75 μm was used, and the thickness of the resin composition layer after drying was 20 μm. Then, the coating was uniformly performed, and drilling was performed with the processing energy described in the column of Example 1 in Table 1.

Example 2: Use of a PET film with a release layer having a total thickness of 100 µm As a release film for laser attenuation, a PET film with a release layer having a total thickness of 100 µm was used, and the thickness of the resin composition layer after drying was It apply | coated uniformly so that it might be set to 20 micrometers, and the hole was drilled with the processing energy as described in the column of Example 2 of Table 1.

Example 3: Use of PET film with release layer having a total thickness of 125 μm PET film with release layer having a total thickness of 125 μm was used as a release film for laser attenuation, and the thickness of the resin composition layer after drying Was uniformly applied so as to be 20 μm, and drilling was performed with the processing energy described in the column of Example 3 in Table 1.

Example 4: Use of PET film with a release layer having a total thickness of 100 µm As a release film for laser attenuation, a PET film with a release layer having a total thickness of 100 µm was used, and the thickness of the resin composition layer after drying Was uniformly applied so as to be 8 μm, and drilling was performed with the processing energy described in the column of Example 4 in Table 1.

Example 5: Use of a PEN film with a release layer having a total thickness of 100 μm As a release film for laser attenuation, a PEN film with a release layer having a total thickness of 100 μm was used, and the thickness of the resin composition layer after drying Was uniformly applied so as to be 20 μm, and drilling was performed with the processing energy described in the column of Example 5 in Table 1.

Example 6: Combined use of magnesium oxide and silica as inorganic fillers As inorganic fillers, 75 parts by mass of magnesium oxide (SMO-0.4, manufactured by Sakai Chemical Industry Co., Ltd., average particle size 0.4 μm), silica (SFP) A varnish (resin composition solution) was obtained in the same manner as in the resin composition except that 50 parts by mass of -130MC was added to the varnish.
Using the obtained varnish, using a PET film with a release layer with a total thickness of 100 μm as the release film for laser attenuation, and uniformly applying the resin composition layer after drying to a thickness of 20 μm Then, drilling was performed with the processing energy described in the column of Example 6 in Table 1.

Comparative Example 1: Use of PET Film with Release Layer with a Total Thickness of 38 μm As a release film for laser attenuation, a PET film with a release layer with a total thickness of 38 μm was used, and the thickness of the resin composition layer after drying Was uniformly applied so as to be 20 μm, and drilling was performed with the processing energy described in the column of Comparative Example 1 in Table 1. (Mask diameter 0.4 mm).

Comparative Example 2: Use of PET film with release layer having a total thickness of 50 μm PET film with release layer having a total thickness of 50 μm was used as a release film for laser attenuation, and the thickness of the resin composition layer after drying Was applied uniformly so as to be 20 μm, and drilling was performed with the processing energy described in the column of Comparative Example 2 in Table 1. (Mask diameter 0.4 mm).

Comparative Example 3: Use of PET Film with Release Layer with a Total Thickness of 188 μm As a release film for laser attenuation, a PET film with a release layer with a total thickness of 188 μm was used, and the thickness of the resin composition layer after drying Was uniformly applied so as to be 20 μm, and drilling was performed with the processing energy described in the column of Comparative Example 3 in Table 1.

Comparative Example 4: Use of PET Film with Release Layer with a Total Thickness of 38 μm As a release film for laser attenuation, a PET film with a release layer with a total thickness of 38 μm was used, and the thickness of the resin composition layer after drying Was uniformly applied so as to be 8 μm, and drilling was performed with the processing energy described in the column of Comparative Example 4 in Table 1 (mask diameter 0.4 mm).

Comparative Example 5: Use of Resin Composition with Low Peeling Peel Strength as Resin Composition As epoxy resin, biphenyl aralkyl type epoxy resin (NC-3000-H, manufactured by Nippon Kayaku Co., Ltd.) and naphthalene type epoxy resin (HP4710) In the same manner as the resin composition except that 60.2 parts by mass of bisphenol A type epoxy resin (Epicoat 1001, manufactured by Mitsubishi Chemical Corporation) and no inorganic filler are blended instead of DIC Co., Ltd. (Resin composition solution) was obtained.
Using the resulting varnish, using a PET film with a release layer with a total thickness of 75 μm as a release film for laser attenuation, apply uniformly so that the thickness of the resin composition layer after drying is 20 μm. Drilling was performed with the processing energy described in the column of Comparative Example 5 in Table 1.

Wet roughening treatment and conductor layer plating In Examples 1 to 6 and Comparative Examples 1 to 5, the PET film with a release layer was peeled off after laser drilling, and surface treatment of the insulating layer also serving as desmear treatment was performed. Surface treatment is desmear treatment process (swelling: Updes MDS-37, roughening: Updes MDE-40 and Updes ELC-SH, neutralization: Updes MDN-62) manufactured by Uemura Kogyo Co., Ltd. It was carried out by passing through a process of 5 minutes, roughening 70 ° C. × 20 minutes and neutralization 35 ° C. × 5 minutes. With an electroless copper plating process manufactured by Uemura Kogyo (names of chemicals used: MCD-PL, MDP-2, MAT-SP, MAB-4-C, MEL-3-APEA ver. 2) Electrolytic copper plating was applied, and drying was performed at 130 ° C. for 1 hour. In Comparative Example 5, since swelling occurred in the electroless copper plating layer after drying, subsequent evaluation could not be performed. Subsequently, electrolytic copper plating was performed so that the thickness of the plated copper was 18 μm, and drying was performed at 180 ° C. for 1 hour.

Measurement method 1) Measuring top and bottom diameters of vias Observe blind vias with a digital microscope (Keyence VHX-2000) and measure the top and bottom diameters of the vias at 10 approximate circle diameters. The average value was obtained. The results are shown in Table 1.
2) Adhesive strength of plated copper A laminated plate provided with plated copper was prepared, and the adhesive strength of the plated copper was measured three times according to JIS C6481, and the average value was obtained. About the sample swollen by the drying after electrolytic copper plating, it evaluated using the part which is not swollen. The results are shown in Table 1.

For Example 2 and Comparative Example 1, after forming the via hole, the resin laminate was cut, and the cut cross section of the via hole was photographed. The results are shown in FIGS. 2A (Comparative Example 1) and B (Example 2).

DESCRIPTION OF SYMBOLS 1 Resin insulating layer 2 Release film for laser attenuation 3 Via hole 4 Top diameter 5 Bottom diameter 6 Taper

Claims (17)

1. A resin laminate for a printed wiring board comprising a resin insulation layer for forming fine via holes and a release film for laser attenuation laminated on the resin insulation layer, wherein the release film has a thickness of more than 50 μm and 180 μm A resin laminate which is the following.
2. The resin laminate according to claim 1, wherein the release film for laser attenuation is formed of polyester.
3. The polyester is one or two selected from the group consisting of polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polybutylene naphthalate (PBN), polybutylene terephthalate (PBT), and polytrimethylene terephthalate (PTT). The resin laminate according to claim 2, which is a seed or more.
4. The laminate according to any one of claims 1 to 3, wherein a top diameter of the via hole formed in the resin insulating layer is 30 µm or less, and a difference between the top diameter and the bottom diameter is 10 µm or less.
5. The resin laminate according to any one of claims 1 to 4, wherein the resin insulating layer has a thickness of 3 to 50 µm.
6. The resin laminate according to any one of Claims 1 to 5, wherein the resin insulation layer is formed from a thermosetting resin composition.
7. The resin laminate according to claim 6, wherein the thermosetting resin composition comprises an epoxy resin, a cyanate ester compound, and an inorganic filler.
8. The resin laminate according to claim 6 or 7, wherein the thermosetting resin composition is semi-cured.
9. The resin laminate according to any one of claims 1 to 8, wherein a plating peel strength of the resin insulation layer is 0.4 kN / m or more.
10. A method of manufacturing a multilayer printed wiring board,
    A circuit board having a base material and a conductive circuit formed on the base material, the resin laminate according to any one of claims 1 to 9, and the conductive circuit of the circuit board and the resin laminate of the circuit board. Laminated so that the resin insulation layer faces,
    Forming a via hole penetrating from the release film side for laser attenuation of the resin laminate to the resin insulation layer by a laser;
    Peeling off the release film from the resin insulation layer.
11. While the resin laminate is the resin laminate according to claim 8,
    The method according to claim 10, further comprising fully curing the resin insulation layer in a semi-cured state after the circuit board and the resin laminate are laminated and before forming the via hole.
12. The method according to claim 10 or 11, wherein the laser is a carbon dioxide gas laser.
13. The method according to claim 12, wherein the energy of the laser is 0.3 mJ to 5 mJ.
14. The method according to any one of claims 10 to 13, wherein a top diameter of the via hole formed in the resin insulating layer is 30 μm or less, and a difference between the top diameter and the bottom diameter is 10 μm or less.
15. The method further comprises roughening the surface of the resin insulating layer after peeling the release film, forming a conductor layer on the roughened surface by plating, and patterning the conductor layer to form a circuit. The method as described in any one of.
16. A multilayer printed wiring board obtained by the method according to any one of claims 10 to 15.
17. A circuit board having a base material and a conductive circuit formed on the base material, and a resin insulating layer of the resin laminate according to any one of claims 1 to 9 laminated on the circuit board. A multilayer printed wiring board, wherein the resin insulating layer has a via hole formed by a laser, the top diameter of the via hole is 30 μm or less, and the difference between the top diameter and the bottom diameter is 10 μm or less. Wiring board.

Images