JP2010080862A - Printed wiring board and manufacturing method therefor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a printed wiring board which can form a fine conductor circuit which ensures that a conductor circuit has a higher density and computation processings are performed at a higher speed, even though the surface of the conductor circuit is superior in adhesive properties, despite the surface being smooth. <P>SOLUTION: The printed wiring board is formed by an additive process, such that: an interlayer insulating resin layer (A) is formed on an internal layer circuit substrate (F), and a conductor circuit (B) is formed on the surface of the interlayer insulating resin layer (A) by nonelectrolytic plating and/or electrolytic plating, wherein the interlayer insulating resin layer includes at least one layer of sensitive resin layer (a); the underside (Bb) of the conductor circuit (B) is located lower than the surface (At) of the interlayer insulating resin layer (A); and numerical relation 1: (d)≥3 μm, and relation 2:(h)-(d)≥3 μm are satisfied. In the numerical expressions, (d) represents the depth of the underside (Bb) of the conductor circuit (B) from the surface (At) of the interlayer insulation resin layer (A), while (h) represents the thickness of the interlayer insulation resin layer. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a printed wiring board and a method for manufacturing a printed wiring board, and further relates to an interlayer insulating resin for a printed wiring board and an interlayer insulating resin film for a printed wiring board that are suitable for use in the manufacturing method.

  In recent years, printed circuit boards used for electronic devices, communication devices, and the like have been increasingly demanded to increase the density of conductor circuits and increase the processing speed. Accordingly, as a method of manufacturing a multilayer printed wiring board, a build-up manufacturing technique in which interlayer insulating layers are alternately stacked on a conductor layer of a circuit board has attracted attention.

  In general, as a method for forming a conductor circuit of a build-up method, for example, an additive method in which a conductive circuit is formed by electroless plating alone or electroless plating and electrolytic plating on an interlayer resin surface, and an interlayer insulating resin surface is formed in advance. A subtractive method for forming a conductor circuit by etching a conductor layer is known. Usually, it is difficult to increase the density of the conductor circuit by the subtractive method because the etching accuracy of the conductor layer is poor, and the additive method is suitable.

The interlayer insulation resin of the printed wiring board used in the additive method is made by dispersing filler in an epoxy resin. In order to obtain adhesion to the conductor layer, the substrate surface is roughened with a permanganic acid solution or the like. Forming complex irregularities on the order of sub-micron to several microns, this throwing effect improves peel strength (force per unit width required to peel the conductor layer from the insulating resin layer perpendicular to the substrate surface). The adhesion of the conductor circuit is obtained.
However, when the unevenness of the surface of the interlayer insulating resin is large, there is a limit to miniaturization of the conductor circuit because the restriction on the width between the formed conductor circuits is also large. Furthermore, the skin effect increases due to the higher frequency accompanying the higher processing speed, and transmission loss occurs due to unevenness on the surface of the conductor circuit. For this reason, it is necessary to avoid roughening as much as possible and to form a conductor circuit on a completely smooth surface if possible.

Examples of a method for obtaining a peel strength with a conductor layer on a smooth surface include a method of imparting a functional group having high chemical adhesion to the conductor layer on the surface of the interlayer insulating resin layer, a method of forming nano-level unevenness, etc. Has been proposed. (Patent Document 1)
However, in the method of forming a conductor circuit on the surface of the interlayer resin layer, when the width of the conductor circuit is reduced, the adhesion is lowered, and the risk that the conductor circuit is peeled off with a slight impact is increased.

On the other hand, as a method for obtaining a sufficient adhesion of a conductor circuit on a smooth surface, a method of embedding the conductor circuit in an interlayer insulating resin layer has been proposed (Patent Documents 2 and 3).
However, the above-described embedding method is a subtractive method in which the conductor layer is etched to form a conductor circuit, and it is difficult to miniaturize the conductor circuit.
Therefore, in order to realize higher density of conductor circuits and higher processing speed, printed circuit boards with excellent adhesion of conductor circuits are required despite the fact that the surface is smooth with fine conductor circuits. Yes.
JP2008-50541 JP-A-2005-243899 JP2007-2221068

  In order to provide a printed wiring board with a high density of the conductor circuit and a high processing speed, the present invention can form a fine conductor circuit, and the conductor circuit has a smooth surface despite the fact that the surface of the conductor circuit is smooth. It aims at providing the interlayer insulation resin film suitable for the manufacturing method and manufacture of a printed wiring board excellent in adhesiveness.

The inventors of the present invention have arrived at the present invention as a result of intensive studies to solve the above problems.
That is, according to the present invention, an interlayer insulating resin layer (A) is formed on an inner layer circuit board (F), and a conductive circuit (B) is formed on the surface of the interlayer insulating resin layer (A) by electroless plating and / or electrolytic plating. ), And the interlayer insulating resin layer includes at least one photosensitive resin layer (a), and the bottom surface (Bb) of the conductor circuit (B) is an interlayer insulating resin layer ( In the method for producing a printed wiring board by an additive method, wherein the printed wiring board is located below the surface (At) of A) and has a structure satisfying the following mathematical formulas (1) and (2): The interlayer insulating resin layer (A) includes at least one photosensitive resin layer (a), and the interlayer insulating resin layer (A) is subjected to a step (I) of developing and irradiating the conductive circuit pattern shape with ultraviolet rays, and (3) and formula (4) After forming the groove | channel (C) which satisfy | fills, it is a manufacturing method of the printed wiring board characterized by performing the process (II) which forms a conductor circuit (B) in this groove | channel (C).
d ≧ 3 μm (1)
hd ≧ 3 μm (2)
d ′ ≧ 3 μm (3)
hd ′ ≧ 3 μm (4)
[D is the depth of the bottom surface (Bb) of the conductor circuit (B) from the surface (At) of the interlayer insulating resin layer (A); d ′ is the interlayer insulating resin layer (A of the bottom surface (Cb) of the groove (C) ) Represents the depth from the surface (At), and h represents the thickness of the interlayer insulating resin layer. ]

The printed wiring board of the first invention and the printed wiring board obtained by the manufacturing method of the second invention are additive methods capable of forming a fine conductor circuit, and the bottom surface (Bb) of the conductor circuit (B) is interlayer-insulated. By having a structure located below the surface (At) of the resin layer (A), that is, a structure in which the conductor circuit (B) is embedded in the interlayer insulating resin layer (A), the surface is smooth with fine conductor circuits. Despite being excellent in adhesion of conductor circuits.
Further, since the conductor circuit does not peel off in the subsequent process, a printed wiring board suitable for increasing the density of the conductor circuit and increasing the processing speed is provided.

  In the printed wiring board of the present invention, the interlayer insulating resin layer (A) is formed on the inner circuit board (F), and the surface of the interlayer insulating resin layer (A) is electroless plating alone, or electroless plating and electrolytic plating. By this additive method suitable for forming a fine conductor circuit for forming a conductor circuit (B), this interlayer insulating resin layer (A) includes at least one photosensitive resin layer (a).

Furthermore, the bottom surface (Bb) of the conductor circuit (B) has a structure located below the surface (At) of the interlayer insulating resin layer (A), and the interlayer of the bottom surface (Bb) of the conductor circuit (B) By designing the depth (d) of the insulating resin (A) from the surface (At) and the thickness (h) of the interlayer insulating resin layer (A) so that d ≧ 3 μm and hd ≧ 3 μm. Adhesion of the conductor circuit can be obtained.
That is, the following formula (1) and formula (2) are satisfied.
d ≧ 3 μm (1)
hd ≧ 3 μm (2)
Here, d represents the depth (μm) of the bottom surface (Bb) of the conductor circuit (B) from the surface (At) of the interlayer insulating resin layer (A), and h represents the thickness (μm) of the interlayer insulating resin layer.

FIG. 1 is an example of a cross-sectional view of a printed wiring board according to the present invention, and FIG. 2 is a positional relationship between an interlayer insulating resin layer (A), a conductor circuit (B), and an inner layer circuit board (F) of the printed wiring board according to the prior art. It is an example of sectional drawing which shows.
In the conventional printed wiring board (see FIG. 2), the conductor circuit (B) is formed on the surface (At) of the interlayer insulating resin layer, and the bottom surface (Bb) of the conductor circuit (B) and the surface of the interlayer insulating resin layer (At) ) Have the same height, the printed wiring board of the present invention (see FIG. 1) has the bottom surface (Bb) of the conductor circuit (B) lower than the surface (At) of the interlayer insulating resin layer (A). It is located in.

In the manufacturing method of the second invention, the interlayer insulating resin layer (A) includes at least one photosensitive resin layer (a), and thus the interlayer insulating resin layer (A) is irradiated with ultraviolet rays and developed into a conductor circuit pattern shape. The groove (C) having a depth satisfying the following formulas (3) and (4) can be formed by performing the step (I).
d ′ ≧ 3 μm (3)
hd ′ ≧ 3 μm (4)
[D ′ represents the depth (μm) of the bottom surface (Cb) of the groove (C) from the surface (At) of the interlayer insulating resin layer (A), and h represents the thickness (μm) of the interlayer insulating resin layer. . ]

By performing the step (II) of forming the conductor circuit (B) in the groove (C), the bottom surface (Bb) of the conductor circuit (B) can be easily lowered from the surface (At) of the interlayer insulating resin layer (A). It is possible to form a printed wiring board that is positioned at and satisfies the following mathematical formulas (1) and (2).
d ≧ 3 μm (1)
hd ≧ 3 μm (2)
[D represents the depth (μm) from the surface (At) of the interlayer insulating resin layer (A) of the bottom surface (Bb) of the conductor circuit (B), and h represents the thickness (μm) of the interlayer insulating resin layer. . ]

FIG. 3 is an explanatory view of the method for producing a printed wiring board of the present invention according to the steps (I) and (II), and shows an interlayer insulating resin layer (A), a conductor circuit (B), a groove (C), and an inner layer circuit board. It is an example of sectional drawing which shows the positional relationship of (F).
In the printed wiring board manufacturing method of the present invention, a groove (C) having a depth d ′ is formed in the interlayer insulating resin layer (A) by the step (I), and the conductor circuit ( B) is formed.

  The interlayer insulating resin layer (A) may be formed of a photosensitive resin layer (a) and a thermosetting resin layer (b). The photosensitive resin layer (a) and the thermosetting resin layer (b) may be a composite layer composed of one or more layers having different resin compositions.

For example, the photosensitive resin layer (a) is composed of a photosensitive resin layer (ax) and a photosensitive resin layer (ay) having different resin compositions, and the thermosetting resin layer (b) is a thermosetting resin having a different resin composition. Examples thereof include a resin layer (bx) and a thermosetting resin layer (by).
An example of such a composite layer is shown in FIG.
When the inner layer circuit board (F) is the lowermost layer, (2) thermosetting resin layer (b) -photosensitive resin layer (a), (3) thermosetting resin layer in FIG. 4 toward the upper layer. (B) -photosensitive resin layer (ay) -photosensitive resin layer (ax), (4) thermosetting resin layer (by) -thermosetting resin layer (bx) -photosensitive resin layer (ay) -photosensitive The case where it laminates | stacks in order of the conductive resin layer (ax) is mentioned.
As the structure of the interlayer insulating resin layer (A), the resin layer located on the surface of the interlayer insulating resin layer (A) is preferably a photosensitive resin layer (a), more preferably an inner layer circuit board (F). When the lowermost layer is formed, the layers are laminated in the order of thermosetting resin layer (b) -photosensitive resin layer (a) toward the upper layer. In this way, it becomes easy to adjust the depth of the groove (C) for embedding the wiring by the ultraviolet irradiation of the conductive circuit pattern shape and the developing step (I), and the conductive circuit (B) is embedded. It is suitable for manufacturing a printed wiring board having a structure.

In order to obtain the adhesion of the conductor circuit, the bottom surface (Bb) of the conductor circuit (B) of the present invention is usually 3 μm to (h−3) μm from the surface (At) of the interlayer insulating resin layer (A). Located at depth. It is preferably located at a depth of 4 to (h-4) μm, particularly preferably 5 to (h-5) μm.
That is, the depth d from the surface (At) of the interlayer insulating resin layer (A) to the bottom surface (Bb) of the conductor circuit (B) is usually 3 μm or more, preferably 4 μm or more, particularly preferably 5 μm or more. The depth d is usually (h-3) μm or less, preferably (h-4) μm or less, particularly preferably (h-5) μm or less.
If the depth d is less than 3 μm, sufficient conductor circuit adhesion cannot be obtained, and if it is greater than (h-3) μm, there is a problem that the insulation between the layers of the printed wiring board is deteriorated.

  The thickness (h) of the interlayer insulating resin layer (A) is preferably 10 to 200 μm, more preferably 13 to 180 μm, and particularly preferably 15 to 150 μm in order to fill the inner layer circuit pattern and the surface via hole. Within this range, the printed wiring board can be made thin and the insulation between the layers is excellent.

  Known metals can be used as the metal constituting the conductor circuit (B), and examples thereof include copper, silver, gold, iron, nickel, chromium, zinc, aluminum, and magnesium. These can be used alone or in combination of two or more. Of these, copper, silver, gold, and aluminum are more preferable from the viewpoint of electrical conductivity.

  The height of the conductor circuit (B) is usually 3 to 50 μm, preferably 4 to 40 μm, particularly preferably 5 to 30 μm, in order to pass an electric signal. If it is less than 3 μm, the electric resistance increases, and if it is more than 50 μm, there is a problem that the productivity of the printed wiring board decreases.

Although the photosensitive resin which comprises the photosensitive resin layer (a) is not specifically limited, photosensitive acrylic resin (a1), photosensitive polyimide resin (a2), photosensitive epoxy resin (a3), diazonaphthoquinone derivative containing resin (a4) ) And the like. These may be used alone or in combination of two or more.
Among these photosensitive resins, the photosensitive acrylic resin (a1) and the polyimide resin (a2) are preferable from the viewpoints of mechanical characteristics and dielectric characteristics.

As the photosensitive acrylic resin (a1), a known product can be used, and examples thereof include a combination of a polyfunctional (meth) acrylic compound having two or more (meth) acrylic groups in one molecule and a photopolymerization initiator.
For example, a photosensitive resin composed of a binder polymer and a (meth) acryl monomer and / or a (meth) acryl oligomer (see, for example, JP-A-7-181676), a (meth) acryl group is introduced into a part of an epoxy resin And the like (see, for example, JP-A-61-59447, JP-A-6-317904, and JP-A-11-43654).
In the present invention, "(meth) acryl ..." represents "acryl ..." and "methacryl ...".

Known compounds can be used as the photosensitive polyimide resin (a2), and examples thereof include polyamic acid obtained by reacting diamine and tetracarboxylic dianhydride, and a compound obtained by adding a photosensitive group to polyimide.
For example, an ion-bonded photosensitive polyimide obtained by mixing a polyamic acid with a compound having a tertiary amine and a (meth) acryloyl group to form a photosensitive polyimide (see, for example, JP-A No. 54-145794), polyamic acid An ester bond type photosensitive polyimide having a methacryloyl group introduced into a carboxyl group via an ester bond (see, for example, Japanese Patent Publication Nos. 55-030207 and 55-041422), and an isocyanate compound having a methacryloyl group as a polyamic acid Photosensitive polyimide introduced into the carboxyl group site (see, for example, JP-A-59-160140, JP-A-03-170547, JP-A-03-186847, JP-A-61-118424), And polyamic acid and (meth) acrylic compound Combined photosensitive polyimide (for example, see JP-A-11-52569), photosensitive polyimide mixed with polyamic acid and photoacid generator (for example, see JP-A-10-316751), polyamic acid and Photosensitive polyimide mixed with a photobase generator (for example, see JP-A-6-295063), photosensitive polyimide mixed with polyamic acid and diazonaphthoquinone derivative, photosensitive polyimide made of polyimide having a benzophenone skeleton, polyamic Photosensitive polyimide composed of acid, methylol-based crosslinking agent and photoacid generator, photosensitive polyimide mixed with phenolic hydroxyl group-containing polyimide and diazonaphthoquinone derivative (for example, "high functionalization and applied technology of polyimide", Published by Science & Technology, 115-12 See), etc. page.

As the photosensitive epoxy resin (a3), a known product can be used, and examples thereof include a combination of a polyfunctional epoxy resin having two or more epoxy groups in one molecule and a photocationic polymerization initiator.
For example, a resin composition comprising a polyfunctional epoxy resin and a sulfonium salt (for example, see JP-A-5-255240), a resin composition comprising a polyfunctional epoxy resin and a phenol resin (for example, JP-A-63-71840). And a resin composition comprising a polyfunctional epoxy resin, a phenol resin, and an unsaturated carboxylic acid (for example, see JP-A-8-179506).

As the diazoquinone derivative-containing resin (a4), a known product can be used, and a combination of a diazoquinone derivative and a thermoplastic resin can be used.
The diazoquinone derivative is a compound having a 1,2-benzoquinonediazide or 1,2-naphthoquinonediazide structure. US Pat. Nos. 2,772,972, 2,797,213, 3,669, It is a known substance from No. 658.

  As the thermoplastic resin, known products can be used, and examples thereof include polyimide resin, polyamic acid resin, phenol resin, polymethyl methacrylate, polystyrene resin, styrene-maleic anhydride copolymer, phenoxy resin, and polycarbonate resin.

As the thermosetting resin constituting the thermosetting resin layer (b), epoxy resin (b1), polyimide resin (b2), cyanate resin (b3), resins having other reactive groups, and the like can be used.
Of these curable resins, epoxy resin (b1) and polyimide resin (b2) are more preferable from the viewpoints of mechanical properties and dielectric properties.

The epoxy resin (b1) is composed of an epoxy resin and a curing agent.
As an epoxy resin and a hardening | curing agent, the well-known thing normally used as an epoxy resin and a hardening | curing agent (For example, a "practical plastic dictionary", an industrial research meeting, Inc., May 1, 1993 publication, and described in pages 211-225. Can be used.
For example, a resin composition comprising an epoxy resin and an amine compound, a resin composition comprising an epoxy resin and an acid anhydride, a resin composition comprising an epoxy resin and a phenol resin, and a resin composition comprising an epoxy resin and a carboxylic acid (for example, “ Introductory Epoxy Resin ”, published by Kobunshi Publishing Co., Ltd.), see pages 69 to 105).

  The polyimide resin (b2) is composed of a polyimide resin composed of diamine and tetracarboxylic dianhydride and a precursor polyamic acid (for example, JP-A 63-175024, JP-A 63-314240, JP-A 1-131241, JP-A-1-131242, JP-A-1-131243, JP-A-1-131244, and JP-A-2-53827).

  As the cyanate resin (b3), known products can be used (see, for example, German Patent No. 2533122, International Patent No. 88/05443, and Japanese Patent Application Laid-Open No. 8-269325).

  As the resin having another reactive group as the thermosetting resin, a known compound having a polymerizable double bond can be used (for example, see JP-A-2001-279110).

  Additives can be further added to the photosensitive resin composition and the curable resin composition in the present invention as necessary. Examples of the additive include an inorganic filler and a leveling agent.

As the inorganic filler, inorganic oxides and inorganic salts can be used.
Known inorganic oxides can be used, and specific examples include titanium oxide, silicon oxide, and aluminum oxide. Known inorganic salts can be used, and specific examples include calcium carbonate and barium sulfate.
Among these, from the viewpoints of electrical characteristics (wet heat reliability / dielectric characteristics), heat resistance and chemical resistance, inorganic oxides are preferable, and silicon oxide and titanium oxide are more preferable. Particularly preferred is silicon oxide.

  As a leveling agent, a silicone leveling agent, a polyether leveling agent, an alcohol leveling agent, etc. can be used.

As a method of forming the interlayer insulating resin layer (A) before the ultraviolet irradiation of the present invention,
(I) A resin varnish obtained by dissolving / dispersing the resin composition constituting the interlayer insulating resin layer (A) in a predetermined organic solvent is applied to the inner circuit board (F), and then the solvent is dried by heating and / or hot air blowing. Forming the interlayer insulating resin layer (A),
(Ii) Applying the resin varnish to the support base film (D) and drying it, heating the interlayer insulating resin film (E) for printed wiring board provided with the interlayer insulating resin layer (A) to the inner circuit board (F) The method of forming an interlayer insulation resin layer (A) by performing the process of carrying out pressure lamination under conditions etc. is mentioned.

The interlayer insulating resin layer (A) of the interlayer insulating resin film for printed wiring board (E) can form a composite layer by performing a resin varnish application and drying process twice or more.
For example, as shown in FIG. 5, when the support base film (D) is the lowermost layer, (2) photosensitive resin layer (a) -thermosetting resin layer (b) in FIG. (3) photosensitive resin layer (ax) -photosensitive resin layer (ay) -thermosetting resin layer (b), (4) photosensitive resin layer (ax) -photosensitive resin layer (ay) -thermosetting Examples thereof include an interlayer insulating resin film (E) for printed wiring boards, which is laminated in the order of resin layer (bx) -thermosetting resin layer (by).
These methods (i) and (ii) can be performed singly or two or more times. Preferred is a method of pressure laminating an interlayer insulating resin film (E) for printed wiring boards under heating conditions, and particularly preferred is that the interlayer insulating resin layer (A) is heated with the photosensitive resin layer (a). In this method, the interlayer insulating resin film for printed wiring board (E) composed of the curable resin layer (b) is pressure-laminated under heating conditions. This is preferable because the productivity of the printed wiring board is greatly improved.

The application of the resin varnish can be performed using a known method such as curtain coating, roll coating, spray coating, or screen printing.
The drying conditions vary depending on the solvent to be used, but the drying is preferably performed at 50 to 200 ° C. for 2 to 30 minutes, and is appropriately determined depending on the complex viscosity of the interlayer insulating resin after drying, the residual solvent amount (% by weight), and the like. .

  As the inner circuit board (F), a glass epoxy, metal board, polyester board, polyimide board, thermosetting polyphenylene ether board or the like can be used, and the circuit surface may be roughened in advance.

Examples of the supporting base film (D) include polyolefins such as polyethylene and polyvinyl chloride, polyesters such as polyethylene terephthalate, and polycarbonate. The thickness of the base film is preferably 10 to 150 μm. The width of the base film is not particularly specified as long as it can enter the apparatus, but is preferably 30 to 300 cm.
The base film may be subjected to a mold release treatment in addition to a mat treatment and a corona treatment.
Further, if a support base portion having no resin is provided on both ends or one side of the roll at 5 mm or more, there are advantages such as prevention of resin adhesion to the laminate portion and easy peeling of the support base film.

  The organic solvent is not particularly limited as long as it can dissolve and / or disperse the interlayer insulating resin composition, and adjust the physical properties (viscosity, etc.) applicable to the film production apparatus. For example, N- Known solvents such as methyl pyrrolidone, N, N-dimethylformamide, dimethyl sulfoxide, toluene, ethanol, cyclohexanone, methanol, methyl ethyl ketone, ethyl acetate, acetone and xylene can be used. Of these solvents, those having a boiling point of 200 ° C. or less (toluene, ethanol, cyclohexanone, methanol, methyl ethyl ketone, ethyl acetate, acetone and xylene) are preferable from the viewpoint of the drying temperature of the film, etc., alone or in combination of two or more. It can also be used.

When laminating the interlayer film for printed wiring board (E) on the inner layer circuit board (F) under pressure, it is laminated while being pressurized and heated from the support base film (D) side. Lamination is preferably carried out under reduced pressure from the viewpoint of production stability.
The pressure lamination may be performed by a batch method or a continuous method by a roll method, and is preferably performed simultaneously on both sides.
The laminating temperature is usually 50 to 180 ° C, preferably 60 to 170 ° C, more preferably 70 to 150 ° C. If the temperature is lower than 50 ° C., it is difficult to transfer to the inner layer circuit board (F).
The pressure of the laminate is usually 0.1 to 20 MPa, preferably 0.2 MPa to 15 MPa. If it is less than 0.1 MPa, transfer to the inner circuit board (F) is difficult, and if it is higher than 20 MPa, the thickness of the interlayer insulating resin layer cannot be adjusted. The decompression condition is usually 10 kPa or less, preferably 2.5 kPa or less.

After the interlayer insulating resin layer (A) is formed on the printed wiring board, the conductor circuit pattern-shaped groove (C) is formed by performing the ultraviolet irradiation and development (I) of the conductor circuit pattern shape.
Then, if necessary, the interlayer insulating resin layer (A) may be heat-cured to improve the physical properties, and further roughened by a dry method and / or a wet method in order to improve the adhesion of the conductor circuit.
Then, a printed wiring board can be manufactured by performing process (II) which forms a conductor circuit (B) in a groove | channel (C).

Examples of the method of irradiating with ultraviolet rays in the step (I) include a method of exposing the interlayer insulating resin layer (A) with actinic rays through a photomask having a conductor circuit pattern. The actinic ray used for ultraviolet irradiation is not particularly limited as long as the photosensitive resin layer (a) of the present invention can be reacted. As needed, you may heat-process the photosensitive resin layer (a) for advancing reaction after exposure.
Actinic rays include low-pressure mercury lamp, medium-pressure mercury lamp, high-pressure mercury lamp, ultra-high-pressure mercury lamp, xenon lamp, metal halogen lamp, electron beam irradiation device, X-ray irradiation device, laser (argon laser, dye laser, nitrogen laser, helium cadmium laser) Etc.). Of these, high pressure mercury lamps and ultrahigh pressure mercury lamps are preferred.

Examples of the developing method in the step (I) include a method of dissolving and removing the conductive circuit pattern shape using a developer. The developer is not particularly limited as long as one of the developer and the non-ultraviolet irradiated portion of the photosensitive resin layer (a) is dissolved and the other is not dissolved. Examples of the developer include an alkaline aqueous solution, an acidic aqueous solution, and an organic solvent.
Development methods include a dip method using a developer, a shower method, and a spray method, with the spray method being preferred. The temperature of the developer is preferably 25 to 40 ° C. The development time is appropriately determined according to the depth of the groove (C) to be dissolved and removed and the solubility of the photosensitive resin layer.

  The depth (d ′) of the bottom surface (Cb) of the groove (C) from the surface (At) of the interlayer insulating resin layer (A) is usually 3 μm to (h-3) μm, preferably 4 μm to (h− 4) Located at a depth of [mu] m, particularly preferably 5 [mu] m to (h-5) [mu] m. If it is this range, the printed wiring board which the bottom face (Bb) of a conductor circuit (B) will be located in the depth of 3 micrometers-(h-3) micrometers from the surface (At) of an interlayer insulation resin layer (A) is created. Is easy.

  After the step (I) of irradiating and developing the conductive circuit pattern shape, if necessary, the thermosetting conditions for improving the physical properties of the interlayer insulating resin layer are selected at 130 to 300 ° C. for 10 to 300 minutes. The

  Examples of the dry roughening method of the resin composition surface for improving the adhesion of the conductor circuit include mechanical polishing such as buffing and sandblasting, plasma etching, and the like. On the other hand, the wet roughening method includes chemical treatment such as permanganate, dichromate, ozone, hydrogen peroxide / sulfuric acid, nitric acid and other oxidizing agents.

As a method of forming the conductor circuit (B) in the groove (C) in the step (II), after forming the electroless plating layer,
(I) After forming the plating resist layer on the electroless plating layer, the portion other than the groove (C) is covered by performing ultraviolet irradiation and development on the conductor circuit pattern shape so as to have the same shape as the groove (C). Then, after performing electrolytic plating, the plating resist is peeled off, and a conductive circuit (B) is formed by etching an electroless plating layer that is not electrolytically plated (see FIG. 6).
(Ii) Manufacturing method for forming a conductor circuit (B) by performing electroplating after polishing and removing the electroless plating layer other than the groove (C) located on the surface (At) of the interlayer insulating resin layer (A) (See FIG. 7), and (iii) After electrolytic plating is performed on the entire surface of the interlayer insulating resin layer (A), the plating is polished and removed to the surface (At) of the interlayer insulating resin layer (A). A production method for forming B) (see FIG. 8) and the like can be mentioned.
After the conductor circuit (B) is formed in this way, preferably, the adhesion of the conductor circuit is further improved by performing a heat treatment (annealing treatment) performed at 130 to 300 ° C. for 10 to 300 minutes. You can also.

  The printed wiring board of the present invention repeats the process from the lamination of the interlayer insulating resin film for printed wiring board (E) to the inner circuit board (F) to the formation of the conductor circuit (B) a plurality of times (build-up), A multilayer printed wiring board can be manufactured by laminating build-up layers in multiple stages.

  Hereinafter, although an example and a comparative example explain the present invention further, the present invention is not limited to these. Hereinafter, unless otherwise specified, “%” represents “% by weight” and “parts” represents “parts by weight”.

<Production Example 1>
<Synthesis of photosensitive resin varnish (aw)>
In a three-necked flask equipped with a thermometer, a stirrer, a dropping funnel, and a reflux condenser, 217 parts of a cresol novolac type epoxy resin (Dainippon Ink Chemical Co., Ltd., Epicron N-680, epoxy equivalent = 217) It was dissolved by heating in 196.5 parts of carbitol acetate. Hydroquinone 0.2 part as a polymerization inhibitor and 1.0 part of triphenylphosphine as a catalyst were added and reacted at 85 to 105 ° C. for 16 hours while gradually adding 72.0 parts (1.0 equivalent) of acrylic acid. . Furthermore, 76.0 parts (0.5 equivalent) of tetrahydrophthalic anhydride was added, and an addition reaction was performed at 80 to 90 ° C. for 8 hours. After cooling to room temperature, 36 parts of a hexafunctional acrylic monomer (manufactured by Sanyo Chemical Industries, Ltd., DA-600) and 9 parts of a photopolymerization initiator (manufactured by Ciba Specialty Chemicals, Inc., Irgacure 907) are added and dissolved and stirred. Went. Thus, a photosensitive resin varnish (aw) having a nonvolatile content of 67% by mass was obtained.

<Production Example 2>
<Synthesis of thermosetting resin varnish (bw)>
In a three-necked flask equipped with a thermometer, a stirrer, a dropping funnel, and a reflux condenser, 217 parts of cresol novolac type epoxy resin (Dainippon Ink and Chemicals, Epiklone N-680, epoxy equivalent = 217), phenoxy Type epoxy resin (Japan Epoxy Resin Co., Ltd., Epicoat E1256, epoxy equivalent 7800) 50 parts, and amine curing agent (Nippon Kayaku Co., Ltd., Kayahard A-A, amine equivalent = 126) 89 parts, carbitol acetate 180 parts were stirred and dissolved at 40 ° C. After cooling to room temperature, 2 parts of a curing catalyst (San-Apro Co., Ltd., SA-102) was added and dissolved by stirring. Thus, a thermosetting resin varnish (bw) having a nonvolatile content of 67% by mass was obtained.

<Example 1>
The photosensitive resin varnish (aw) obtained in Production Example 1 was applied to the entire surface of the glass epoxy substrate with a knife coater so that the thickness of the photosensitive resin layer after drying was 40 μm at a coating speed of 0.3 m / min. Thereafter, an interlayer insulating resin layer was formed by drying at 90 ° C. for 4 minutes.
Next, the conductor circuit pattern is exposed with a projection type exposure apparatus, sprayed with a 1% sodium carbonate aqueous solution at 30 ° C. for 15 seconds, developed, washed with water, and in a smooth air dryer (PH-210, manufactured by Espec Corporation), It was dried at 150 ° C. for 60 minutes. Grooves were formed in the interlayer insulating resin layer by the above process.

Next, after electroless copper plating was performed on the entire surface of the substrate, a dry film resist having a thickness of 20 μm (manufactured by Asahi Kasei Co., Ltd., SUNFORT SPG-102) was rolled at a temperature of 105 ° C., a pressure of 0.3 MPa, and a laminating speed of 1.5 m / min. Laminated with.
The conductor circuit pattern is exposed at the same position as the conductor circuit pattern with a projection type exposure apparatus, a 1% sodium carbonate aqueous solution at 30 ° C. is sprayed for 30 seconds and developed, and then a conductor layer having a thickness of 20 μm is formed by electrolytic copper plating. did.
Next, after spraying a 3% sodium hydroxide solution at 50 ° C. with a spray to remove the dry film resist, a 40 ° C. sulfuric acid-hydrogen peroxide aqueous solution (sulfuric acid 1 mol / l, hydrogen peroxide 1 mol / l) is sprayed. The electroless copper plating of the circuit part was dissolved.
Furthermore, in order to stabilize the adhesion of the conductor circuit, an annealing treatment was performed at 170 ° C. for 60 minutes to obtain a printed wiring board (Z1). (D = 30 μm)

<Example 2>
The photosensitive resin varnish (aw) obtained in Production Example 1 was coated on the entire surface of a PET film having a thickness of 50 μm with a roll coater so that the photosensitive resin thickness after drying was 20 μm, and then at 90 ° C. for 4 minutes. A photosensitive resin layer was formed by drying.
Subsequently, the thermosetting resin varnish (bw) obtained in Production Example 2 was applied on the entire surface of the dried resin with a roll coater so that the resin thickness after drying was 30 μm, and then at 90 ° C. for 7 minutes. By drying, a thermosetting resin layer was formed, and an interlayer insulating resin film (Af) for printed wiring boards composed of two layers of a photosensitive resin layer and a thermosetting resin layer was obtained. Next, the obtained interlayer insulating resin film (Af) for printed wiring boards was pressure-transferred to a glass epoxy substrate with a vacuum laminator at a temperature of 90 ° C., a pressure of 0.15 MPa and a pressure of 0.2 kPa at a pressure of 0.2 kPa, and the PET film was peeled off. Thus, an interlayer insulating resin layer was formed.
Subsequently, after irradiation with ultraviolet rays and development to form grooves as in Example 1, a conductor circuit was formed to obtain a printed wiring board (Z2). (D = 20 μm)

<Example 3>
A thermosetting resin varnish (bw) was applied to a PET film having a thickness of 50 μm by a roll coater so that the thermosetting resin thickness after drying was 45 μm, and then dried at 90 ° C. for 4 minutes. A curable resin layer was formed to obtain a printed wiring board film (bf) composed of a thermosetting resin layer.
Next, the obtained printed wiring board film (bf) was pressure-transferred to a glass epoxy substrate at a pressure of 90 kPa, a pressure of 0.15 MPa and a pressure of 0.2 kPa with a vacuum laminator at a pressure of 0.2 kPa, and the PET film was peeled off. A thermosetting resin layer was formed. Next, the photosensitive resin varnish (aw) is applied to a knife coater so that the thickness of the photosensitive resin layer after drying at a coating speed of 0.3 m / min is 5 μm on the glass epoxy substrate on which the thermosetting resin layer is formed. After coating the entire surface, the substrate was dried at 90 ° C. for 4 minutes to form an interlayer insulating resin layer composed of a photosensitive resin layer and a thermosetting resin layer.
Next, a printed wiring board (Z3) was obtained in the same manner as in Example 1. (D = 5μm)

<Comparative Example 1>
A printed wiring board (Z′1) was obtained in the same manner as in Example 1 except that a thermosetting resin varnish (bw) was used instead of the photosensitive resin varnish (aw). (D = 0μm)

<Comparative example 2>
The resin thickness after drying of the photosensitive resin varnish (aw) was 2 μm instead of 20 μm, and the resin thickness after drying of the thermosetting resin varnish (bw) was 45 μm instead of 30 μm. Obtained a printed wiring board (Z′2) in the same manner as in Example 2. (D = 2μm)

<Comparative Example 3>
Instead of the interlayer insulating resin film (Af) for printed wiring board, the printed wiring board film (bf) obtained in Example 3 was first cured at 150 ° C. for 30 minutes instead of ultraviolet irradiation / development and subsequent heat treatment. Thereafter, printing was performed in the same manner as in Example 2 except that the surface of the interlayer insulating resin layer was roughened at 80 ° C. for 15 minutes with an alkaline oxidant composed of permanganate (“Concentrate Compact CP”, manufactured by Atotech Co., Ltd.). A wiring board (Z′3) was obtained. (D = 0μm)

<Performance evaluation>
As the smoothness and adhesion of the printed wiring board, the obtained (Z1) to (Z3) and (Z′1) to (Z′3) surface roughness before electroless plating, the adhesion of the conductor circuit, And the pattern formation property of the conductor circuit was evaluated by the following method.

<Surface roughness>
The surface of the groove (C) portion of the interlayer insulating resin layer immediately before electroless plating is JIS B0601: under the condition of 1250 times magnification using a shape measurement microscope (VD-8550, manufactured by Keyence Corporation). Centerline average roughness (Ra) described in Appendix 2 of 2001 was measured at five locations, and these average values were used as indices. In addition, it has shown that surface roughness is so small that a numerical value is small.

<Adhesion of conductor circuit>
The peel strength of the copper metal layer was measured by the peel strength measurement method described in JIS C6481, by peeling the 20 μm-wide conductor circuit in the printed wiring board on which the conductor circuit was formed, from the end surface with a peel tester.
<Pattern formability>
The peeling of the 10 μm-wide wiring in the printed wiring board on which the conductor circuit was formed was observed under the condition of a microscope magnification of 200 times, and evaluated according to the following criteria.
○: There is no peeling of wiring. ×: There is some peeling of wiring.

  Table 1 shows the characteristics and evaluation results of the interlayer insulating resin layers, the printed wiring board and the printed wiring board obtained in the examples and comparative examples.

From the results of Examples 1 to 3, when a printed wiring board having a structure in which the conductor circuit of the present invention is embedded in an interlayer insulating resin layer is used, the contact strength of the conductor circuit is high although the surface roughness is small. It can be seen that the formability is good. Therefore, when the printed wiring board of the present invention is used, the conductor circuit surface is smooth and the conductor circuit is fine but the adhesion of the conductor circuit is excellent, so that the density of the conductor circuit is increased and the processing speed is high. It can be seen that this is a printed wiring board suitable for manufacturing.
On the other hand, it can be seen from the results of Comparative Examples 1 and 2 that when the conductor circuit is insufficiently embedded in the interlayer insulating resin layer, the adhesion of the conductor circuit is insufficient and there is a problem with pattern formation.
Further, it can be seen from the results of Comparative Example 3 that when the conventional roughening treatment is performed, the surface roughness is large and there is a problem in pattern formability.

When the printed wiring board of the present invention is used, the printed wiring board of the present invention has excellent adhesion of the conductor circuit despite the fact that the surface of the conductor circuit is smooth and the conductor circuit is fine. It is suitable as a printed wiring board suitable for increasing the processing speed.
The printed wiring board of the present invention can be used in electrical products such as personal computers, camera-integrated VTRs, digital video cameras, mobile phones, car navigation systems, and digital cameras.

Interlayer insulation resin layer (A), conductor circuit (B), inner layer circuit board (F), bottom surface (Bb) of conductor circuit and surface of interlayer insulation resin layer (At) after formation of conductor circuit of printed wiring board according to the present invention It is an example of sectional drawing which shows these positional relationships.

Interlayer insulation resin layer (A), conductor circuit (B), inner layer circuit board (F), bottom surface (Bb) of conductor circuit and surface of interlayer insulation resin layer (At) after formation of conductor circuit of printed wiring board according to conventional technology It is an example of sectional drawing which shows these positional relationships.

According to the present invention, the manufacturing method of the step (I) for forming the groove (C) and the step (II) for forming the conductor circuit (B) in the groove (C), the interlayer insulating resin layer (A), the conductor circuit ( B) is an example of a cross-sectional view showing the positional relationship between the inner layer circuit board (F), the groove (C), the bottom surface (Bb) of the conductor circuit, the bottom surface (Cb) of the groove, and the surface (At) of the interlayer insulating resin layer. .

FIG. 5 is a cross-sectional view showing the positional relationship between the combination of the photosensitive resin layer (a), the thermosetting resin layer (b), and the inner layer circuit board (F) with respect to the configuration of the resin layer of the interlayer insulating resin layer (A) according to the present invention It is an example.

It is an example of the interlayer insulation resin film (E) for printed wiring boards in this invention, Comprising: The photosensitive resin layer (a) and thermosetting resin layer (b) of an interlayer insulation resin layer (A), and a support base film ( It is an example of sectional drawing which shows the combination and positional relationship of D).

It is explanatory drawing which shows an example of manufacturing method (i) of the process (II) which forms a conductor circuit (B) in the groove | channel (C) by this invention.

It is explanatory drawing which shows an example of manufacturing method (ii) of the process (II) which forms a conductor circuit (B) in the groove | channel (C) by this invention.

It is an example of the explanatory view showing manufacturing method (iii) of process (II) which forms conductor circuit (B) in slot (C) by the present invention.

Explanation of symbols

(A): Interlayer insulating resin layer (B): Conductor circuit (At): Surface of interlayer insulating resin layer (Bb): Bottom surface of conductor circuit (d): Surface of interlayer insulating resin layer on bottom surface (Bb) of conductor circuit Depth from (At) (h): Thickness of interlayer insulating resin layer (A) (a): Photosensitive resin layer
(Ax): Photosensitive resin layer 1
(Ay): Photosensitive resin layer 2
(B): Thermosetting resin layer
(Bx): Thermosetting resin layer 1
(By): thermosetting resin layer 2
(C): Groove (Cb): Bottom surface of groove (d ′): Depth of groove bottom surface (Cb) from surface (At) of interlayer insulating resin layer (D): Support base film
(E): Interlayer insulating resin film for printed wiring board
(F): Inner layer circuit board

Claims (6)

An additive method in which an interlayer insulating resin layer (A) is formed on an inner layer circuit board (F), and a conductor circuit (B) is formed on the surface of the interlayer insulating resin layer (A) by electroless plating and / or electrolytic plating. The interlayer insulating resin layer includes at least one photosensitive resin layer (a), and the bottom surface (Bb) of the conductor circuit (B) is the surface (At) of the interlayer insulating resin layer (A). ) And a structure satisfying the following mathematical formulas (1) and (2).
d ≧ 3 μm (1)
hd ≧ 3 μm (2)
[D represents the depth of the bottom surface (Bb) of the conductor circuit (B) from the surface (At) of the interlayer insulating resin layer (A), and h represents the thickness of the interlayer insulating resin layer. ] In the method of manufacturing a printed wiring board by the additive method, the interlayer insulating resin layer (A) includes at least one photosensitive resin layer (a), and the interlayer insulating resin layer (A) is irradiated with ultraviolet rays on the conductor circuit pattern shape. And developing step (I) to form a groove (C) satisfying the following mathematical formulas (3) and (4), and then forming a conductive circuit (B) in the groove (C) (II) A printed wiring board manufacturing method, comprising:
d ′ ≧ 3 μm (3)
hd ′ ≧ 3 μm (4)
[D ′ represents the depth of the bottom surface (Cb) of the groove (C) from the surface (At) of the interlayer insulating resin layer (A), and h represents the thickness of the interlayer insulating resin layer. ]   The interlayer insulating resin layer (A) is formed of the photosensitive resin layer (a) and further a thermosetting resin layer (b), and the photosensitive resin layer (a) is a surface of the interlayer insulating resin layer (A). The method for manufacturing a printed wiring according to claim 2, which is located at   Furthermore, before the interlayer insulating resin layer (A) is irradiated with ultraviolet rays, an interlayer insulating resin film (E) for a printed wiring board in which an interlayer insulating resin layer (A) is provided on a support base film (D), The method for producing a printed wiring board according to claim 2 or 3, wherein a step of pressure laminating the inner layer circuit board (F) under a heating condition is performed. An interlayer insulating resin film for printed wiring boards comprising an interlayer insulating resin layer (A) comprising a photosensitive resin layer (a) and a thermosetting resin layer (b), and a support film (D) ( E).   6. A method for producing a printed wiring board, comprising the step of pressure laminating the inner layer circuit board (F) under heating conditions using the interlayer insulating resin film for wiring boards (E) according to claim 5.

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