JP2000261140A - Manufacture of printed circuit board - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method of manufacturing a printed circuit board that assures excellent connection and reliability by forming a smooth substrate having through holes and conductive circuits and thereby forming thereon interlayer insulation layers and upper layer conductive circuits. SOLUTION: In a method of manufacturing a printed circuit board, a mask having an aperture at the area where a conductive circuit non-forming and conductor circuit external edge are overlapped is placed on the insulated substrate, where the through holes 9 and conductive circuits are formed, the through holes 9 are filled with resin filling material 10, and this mask is coated with the resin filling material 10. As a result, a layer of resin filling material 10 is formed at the external edge area of the conductor non-forming area and conductor circuit.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a printed wiring board capable of forming a flat substrate having a through hole and a lower conductive circuit.

[0002]

2. Description of the Related Art A multilayer printed wiring board called a so-called multilayer build-up wiring board is manufactured by a semi-additive method or the like.
m on a resin substrate reinforced with glass cloth, etc.
It is manufactured by alternately laminating a conductor circuit made of copper or the like and an interlayer resin insulating layer. The connection between the conductor circuits via the interlayer resin insulation layer of the multilayer printed wiring board is performed by via holes.

Conventionally, build-up multilayer printed wiring boards have been manufactured by a method disclosed in, for example, Japanese Patent Application Laid-Open No. 9-130050. That is, first, a through-hole is formed in the copper-clad laminate on which the copper foil is stuck, and then a through-hole is formed by performing an electroless copper plating process. Subsequently, the surface of the substrate is etched into a conductor pattern using a photolithography technique to form a conductor circuit. Next, on the surface of the formed conductor circuit,
After forming a roughened layer by electroless plating or etching, forming an insulating resin layer on the roughened layer, performing exposure and development processing to form a via hole opening,
After V curing and main curing, an interlayer resin insulating layer is formed. Further, after roughening the interlayer resin insulation layer with an acid or an oxidizing agent, a thin electroless plating film is formed, a plating resist is formed on the electroless plating film, and then a thick film is formed by electrolytic plating. Then, after removing the plating resist, etching is performed to form a conductor circuit. By repeating this, a build-up multilayer printed wiring board is obtained.

In such a multilayer printed wiring board,
When a conductive circuit is formed by etching a copper-clad substrate, irregularities are formed on the substrate. In addition, in the substrate immediately after the formation of the through hole, a large number of through holes exist in the substrate. Therefore, if an attempt is made to form an interlayer resin insulation layer on the substrate in this state, the interlayer resin insulation layer to be formed becomes severe due to the irregularities and through holes on the surface of the substrate. Via holes and connection pads may be deformed, resulting in poor connection and the like. Therefore, in order to flatten the surface of the substrate on which the conductor circuit is formed, a resin filler is usually filled in the through-holes and portions where the conductor circuit is not formed.

Japanese Patent Application Laid-Open No. 9-191178 discloses a method of filling a resin filler into a through-hole or a portion where a conductor circuit is not formed. According to this method, a resin filler is applied to the substrate on which the through-holes and the conductor circuits are formed to form a layer of the resin filler, which is then dried to a semi-cured state, and then the surface is polished. This exposes the land portion of the through hole and the conductor circuit (hereinafter, the conductor layer including the land portion of the through hole is also referred to as a conductor circuit), and planarizes the entire substrate. Thereafter, by forming an interlayer resin insulating layer on the flattened substrate, a multilayer printed wiring board excellent in the connectivity and reliability of the conductor circuit can be obtained.

[0006]

However, in this method, a resin filler is applied to the entire surface of the substrate, and is polished after being semi-cured. If the degree of curing is insufficient, the polishing is carried out. Even if foreign matter such as resin dust, copper chips, grinding stones, etc. stabs into the resin filler layer and forms an interlayer resin insulation layer on it, these foreign matter may cause delamination or semi-curing. As a result, the resin is removed and a portion where the substrate does not become flat locally occurs, which greatly affects the connectivity and reliability of the conductor circuit.

Further, since the entire surface of the substrate is covered with the resin filler, the conductor circuit may not be completely exposed even when the polishing is performed. In this case, a connection failure occurs. Further, if the polishing is performed again in order to completely expose the conductor circuit, there is a disadvantage that a part of the conductor circuit becomes too thin or completely disappears.

The present invention has been made to solve the above-mentioned problem, and an object of the present invention is to form a smooth substrate having a through hole and a conductive circuit, and as a result, an interlayer resin is formed thereon. An object of the present invention is to propose a method for manufacturing a printed wiring board that can be formed into a printed wiring board having excellent connectivity and reliability by forming an insulating layer and an upper conductor circuit.

[0009]

Means for Solving the Problems The inventors of the present invention have made intensive studies for realizing the above object, and as a result, have arrived at an invention having the following content as a gist configuration. That is, the first method for manufacturing a printed wiring board of the present invention comprises the steps of: forming a through-hole and a conductive circuit on an insulating substrate in which the through-hole is filled with a resin filler; Place a mask with an opening at the part overlapping the outer edge,
By applying a resin filler, a layer of the resin filler is formed on the non-conductor-circuit-forming portion and the outer edge of the conductor circuit.

In a second method of manufacturing a printed wiring board according to the present invention, a conductive circuit non-forming portion is formed on an insulating substrate in which a through hole and a conductive circuit are formed, and the through hole is filled with a resin filler. A mask provided with an opening in a portion overlapping with or a smaller area than the mask is placed, and a resin filler is applied to form a layer of the resin filler in a portion where the conductor circuit is not formed.

[0011] In the above method of manufacturing a printed wiring board,
Specifically, through at least the following steps (a) to (e), a resin insulating layer is formed on the insulating substrate on which the through holes and the conductor circuits are formed. (A) a step of filling the through hole with a resin filler and drying; and (b) a layer of the resin filler on an insulating substrate by using the first or second method of manufacturing a printed wiring board of the present invention. (C) drying the resin filler layer formed in the step (b), (d) polishing the dried resin filler layer, and (e) resin filling after polishing. The process of curing the layer of material

In the method for manufacturing a printed wiring board, it is preferable that the roughened surface of the conductor circuit be flattened by etching before or after the step (d). Further, the thickness of the insulating layer constituting the insulating substrate is set to 0.1.
It is preferably from 5 to 1.5 mm.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION According to a first method of manufacturing a printed wiring board of the present invention, a through hole and a conductive circuit are formed,
On an insulating substrate filled with a resin filler in the through hole, a mask provided with an opening at a portion overlapping the conductor circuit non-forming portion and the outer edge of the conductor circuit is placed, and the resin filler is applied. A layer of a resin filler is formed on the non-conductive circuit forming portion and the outer edge of the conductive circuit.

According to a second method of manufacturing a printed wiring board of the present invention, a through-hole and a conductive circuit are formed, and the through-hole is filled with a resin filler, and overlaps with the non-conductive-circuit-forming portion on the insulating substrate. The method is characterized in that a mask having an opening provided in a part thereof or a narrower area is placed thereon, and a resin filler is applied to form a layer of the resin filler in the portion where the conductor circuit is not formed.

In the first and second methods of manufacturing a printed wiring board according to the present invention, the through-hole is first filled with a resin filler, so that the resin filler having a viscosity suitable for filling the through-hole is reliably used. Since the through holes can be filled, the unfilled through holes are eliminated, and the resin filler layer is flattened.

Further, since the area for forming the resin filler layer is small as compared with the case where the resin filler is applied to the entire insulating substrate, the heat spreads over the entire resin filler layer during drying, so It is possible to prevent peeling of the resin filler layer due to semi-curing and insufficient semi-curing, and peeling of the interlayer resin insulating layer due to foreign matter sticking during polishing.

Further, even after the resin filler is filled, most of the conductive circuit is exposed, so that the conductive circuit is hardly unexposed due to the residual polishing of the resin filler. Connection failure with the upper-layer conductor circuit can be prevented.

Further, since the substrate manufactured through the above steps (a) to (e) is flattened, warpage of the upper conductor circuit formed thereon and peeling of the interlayer resin insulating layer do not occur. Therefore, the connectivity and reliability of the printed wiring board can be ensured.

In particular, according to the second aspect of the present invention, since no resin filler layer is formed on the conductor circuit, the conductor circuit is not unexposed, and the connection failure with the upper conductor circuit formed thereon is reduced. It can be prevented more reliably. In addition, if the height of the resin filler layer can be made the same as the height of the conductor circuit, the polishing step of the resin filler layer can be omitted.

(1) In the first method of manufacturing a printed wiring board of the present invention, first, a resin filler is filled in the through hole of the insulating substrate in which the through hole and the conductive circuit are formed.

As the insulating substrate, a resin substrate is desirable, and specific examples thereof include a glass epoxy substrate, a polyimide substrate, a bismaleimide-triazine resin substrate, a fluororesin substrate, a ceramic substrate, and a copper-clad laminate. . In the present invention, a through hole is formed in the insulating substrate by a drill or the like, and the wall surface of the through hole and the surface of the copper foil are subjected to electroless plating to form a surface conductive film and a through hole. Copper plating is preferred as the electroless plating. Further, the thickness of the insulating layer constituting the insulating substrate is preferably 0.5 to 1.5 mm. If the thickness of the insulating layer is less than 0.5 mm, warpage is likely to occur due to heat history, and the thickness is 1.
If it exceeds 5 mm, warpage due to heat history is unlikely to occur, but the printed wiring board becomes too thick and is not economical. In the production method of the present invention, the thickness of the insulating layer is as thick as 0.8 mm or more, and it is difficult to simultaneously perform the filling of the resin filler into the through holes and the formation of the layer of the resin filler on the substrate. It is effective in some cases, and more effective when the thickness is 1.1 mm or more.

After the electroless plating, the inner wall of the through hole and the surface of the electrolytic plating film are generally roughened. As the roughening treatment method, for example, blackening (oxidation) -reduction treatment,
Spray treatment with a mixed aqueous solution of an organic acid and a cupric complex,
For example, treatment by Cu-Ni-P needle-like alloy plating may be used. In some cases, heat treatment for removing extra components (moisture, solvent, and the like) of the substrate having the roughened surface may be performed.

Thereafter, an etching resist having a conductor circuit shape is formed on the substrate on which the electroless plating has been performed, and a conductor circuit is formed by performing etching. The resin filler is filled in the through holes.

The resin filler is desirably composed of a resin component, a curing component and other additional components. This resin filler has a viscosity at 23 ± 1 ° C. of 30.
It is preferable to adjust the pressure to about 100 Pa · s.

Examples of the resin component include a raw material monomer of a thermosetting resin such as an epoxy resin.

The curing component is preferably an imidazole curing agent. As the imidazole curing agent, for example,
2-methylimidazole, 4-methyl-2-ethylimidazole, 2-phenylimidazole, 4-methyl-2
-Phenylimidazole, 1-benzyl-2-methylimidazole, 2-methylimidazole, 2-isopropylimidazole, 1-cyanoethyl-2-ethyl-4-
Methyl imidazole, 1-cyanoethyl-2-undecyl imidazole and the like can be mentioned.

Among them, it is desirable to use an imidazole curing agent which is liquid at 25 ° C. Examples of such a curing agent include 1-benzyl-2-methylimidazole,
1-cyanoethyl-2-ethyl-4-methylimidazo-
And 4-methyl-2-ethylimidazole. The content of the imidazole curing agent in the resin filler is desirably 1 to 10% by weight.

Examples of the other additional components include inorganic particles such as silica, alumina, mullite, and zirconia, and a leveling agent. The average particle diameter of the inorganic particles is desirably 0.1 to 5.0 μm, and the amount of the inorganic particles is about 1.0 to 2.0 times the weight of the bisphenol epoxy resin. Desirably. Examples of the leveling agent include Perenol S4 manufactured by San Nopco.

To fill the resin filler in the through hole, a mask having an opening at a portion overlapping with the through hole is placed on an insulating substrate, and a squeegee holding the resin filler is moved on the mask to open the mask. This is performed by pushing the resin filler from the portion into the through hole. The squeegee used at this time is not particularly limited as long as it is generally used for manufacturing a printed wiring board, and the material, hardness and the like are not particularly limited. Among them, those having a hardness of 50 to 90 ° are preferable. . As the rubber having the above characteristics, for example,
Polyurethane.

The above hardness refers to the hardness as measured by an A-type hardness meter specified in JIS K6301. Hardness 5
The reason why the angle is 0 to 90 ° is preferable because the resin filler is easily filled into the opening of the mask, and the squeegee does not set even when repeatedly used. The resin filler filled in the through-hole may be dried to a semi-cured state, but the resin filler may be continuously applied between the conductor circuits without drying.

(2) After the above steps, a mask having an opening provided on a portion where the conductor circuit is not formed and a portion overlapping with the outer edge of the conductor circuit is placed, and a resin filler is applied to form a conductor circuit non-formation portion. And forming a resin filler layer on the outer edge of the conductor circuit.

At this time, it is preferable that the composition of the resin filler is the same as the one filled with the through holes, except for the amount of the viscosity adjusting component. This is because it is easier to take measures to minimize the effects of curing and various thermal histories when the coefficient of linear expansion is the same. The viscosity may be changed as appropriate depending on the thickness of the metal layer of the conductor circuit, the filling area, the application temperature, the humidity, and the like. In this case, however, it is preferable that the composition of the solid is not changed. The application method may be the same as the filling method of the resin filler in the through hole filling.

Next, the resin filler layer formed in the through-hole, the portion where the conductor circuit is not formed, and the outer edge portion of the conductor circuit is dried to a semi-cured state (cured state of about 60 to 70%). I do. The reason why the resin filler layer is made to be in a semi-cured state is that when the resin filler is completely cured, it becomes difficult to perform polishing.On the other hand, when the semi-curing is insufficient, foreign substances are generated during polishing. This is because there is a possibility that the interlayer insulating layer may swell due to stabbing in the filler layer or the resin filler layer may be peeled off. Drying is performed, for example, at 100 ° C. for 20 minutes. In addition, step curing may be performed in which heating is first performed at a low temperature and gradually increased to a high temperature.

(3) Usually, as described above, the inside of the through hole is filled with a resin filler, and the second half curing in which a layer of the resin filler is formed on one side of the conductor circuit non-formed portion and the outer edge of the conductor circuit is performed. Subsequently, a layer of a resin filler is similarly formed on the back surface and semi-cured.

(4) Since the resin filler layer formed through the above steps has many portions higher than the height of the conductor circuit, the resin filler layer is polished to grind the resin filler layer, Is also ground to flatten both main surfaces of the substrate. The polishing is performed by a belt sander using abrasive paper, buff polishing using an abrasive, jet scrub, or the like. Among these, a method using abrasive paper such as a belt sander is particularly desirable. This is because polishing the semi-cured resin filler layer with an abrasive or the like may cause peeling. The material, material, and count of the abrasive paper are not particularly limited.

Thereafter, if necessary, the roughened surface formed on the surface of the conductor circuit before and after the polishing step may be removed by etching. Thereby, the land portion of the through hole and the surface of the conductor circuit can be smoothed.

(5) Thereafter, the resin filler layer is completely cured. The curing is desirably performed at a temperature of 50 to 250 ° C. As an example of the curing conditions, there is a method of heating at 100 ° C. for 1 hour and then heating at 150 ° C. for 1 hour. If necessary, step hardening may be performed by sequentially changing the temperature from a low temperature to a high temperature and then hardening.

(6) After that, a roughening process of the conductor circuit is performed.
Examples of the roughening treatment method include a blackening (oxidation) -reduction treatment, a spray treatment with a mixed aqueous solution of an organic acid and a cupric complex, and a treatment with Cu-Ni-P alloy plating.

(7) Thereafter, an interlayer insulating layer is provided on the roughened conductor circuit. As a material of the interlayer resin insulating layer, a thermosetting resin, a thermoplastic resin, a resin obtained by sensitizing a part of the thermosetting resin, or a composite resin thereof can be used. The interlayer insulating layer may be formed by applying an uncured resin, or may be formed by thermocompression bonding an uncured resin film. Further, a resin film in which a metal layer such as a copper foil is formed on one surface of an uncured resin film may be attached. When such a resin film is used, an opening is formed by irradiating a laser beam after etching a metal layer in a via hole forming portion. As the resin film having the metal layer formed thereon, a resin-coated copper foil or the like can be used.

In forming the interlayer insulating layer, an adhesive layer for electroless plating can be used. The most suitable adhesive for electroless plating is one in which heat-resistant resin particles soluble in a cured acid or oxidizing agent are dispersed in an uncured heat-resistant resin hardly soluble in an acid or oxidizing agent. is there. By treating with an acid or an oxidizing agent, the heat-resistant resin particles are dissolved and removed, and a roughened surface composed of an octopus pot-shaped anchor can be formed on the surface.

In the above-mentioned adhesive for electroless plating, particularly as the heat-resistant resin particles cured, (a) a heat-resistant resin powder having an average particle diameter of 10 μm or less, and (b) an average particle diameter of 2 μm or less. Aggregated particles obtained by aggregating heat-resistant resin powder,
(c) a mixture of a heat-resistant resin powder having an average particle diameter of 2 to 10 μm and a heat-resistant resin powder having an average particle diameter of 2 μm or less, (d)
Pseudo particles obtained by adhering at least one of a heat-resistant resin powder or an inorganic powder having an average particle diameter of 2 μm or less to the surface of a heat-resistant resin powder having an average particle diameter of 2 to 10 μm, A mixture of 0.1 to 0.8 μm heat-resistant powder resin powder and a heat-resistant resin powder having an average particle diameter of more than 0.8 μm and less than 2 μm, (f) an average particle diameter of 0.1 to 1.0 μm It is desirable to use heat-resistant resin powder. They are,
This is because a more complicated anchor can be formed.

The depth of the roughened surface formed by acid treatment or the like is as follows:
Rmax = 0.01 to 20 μm is desirable. This is for ensuring adhesion to the conductor circuit. In particular, in the semi-additive method, 0.1 to 5 μm is desirable. This is because the electroless plating film can be removed while ensuring adhesion. As the heat-resistant resin hardly soluble in an acid or an oxidizing agent, a “resin composite composed of a thermosetting resin and a thermoplastic resin” or a “resin composite composed of a photosensitive resin and a thermoplastic resin” is desirable. This is because the former has high heat resistance, and the latter can form an opening for a via hole by photolithography.

As the thermosetting resin, for example, epoxy resin, phenol resin, polyimide resin and the like can be used. Examples of the photosensitized resin include those obtained by subjecting a thermosetting group to methacrylic acid or acrylic acid to undergo an acrylation reaction. In particular, an acrylated epoxy resin is most suitable. As the epoxy resin, a novolak type epoxy resin such as a phenol novolak type and a cresol novolak type, and an alicyclic epoxy resin modified with dicyclopentadiene can be used.

As the thermoplastic resin, polyether sulfone (PES), polysulfone (PSF), polyphenylene sulfone (PPS), polyphenylene sulfide (PPES), polyphenyl ether (PP
E), polyetherimide (PI), fluororesin and the like can be used. The mixing ratio of the thermosetting resin (photosensitive resin) and the thermoplastic resin is preferably thermosetting resin (photosensitive resin) / thermoplastic resin = 95/5 to 50/50. This is because a high toughness value can be secured without impairing the heat resistance.

The mixing weight ratio of the heat-resistant resin particles is preferably 5 to 50% by weight, more preferably 10 to 40% by weight, based on the solid content of the heat-resistant resin matrix. As the heat-resistant resin particles, an amino resin (a melamine resin, a urea resin, a guanamine resin), an epoxy resin, or the like is desirable.

(8) Next, while the interlayer insulating resin layer is cured, an opening for forming a via hole is provided in the interlayer resin layer. Opening of the interlayer insulating resin layer is performed using laser light or oxygen plasma when the resin matrix of the adhesive for electroless plating is a thermosetting resin, and exposed when the resin matrix is a photosensitive resin. Performed by development processing. In the exposure and development process, a photomask (preferably a glass substrate) on which a circular pattern for forming a via hole is drawn is brought into close contact with the photosensitive interlayer resin insulating layer on the circular pattern side. After mounting, the substrate is exposed and immersed in a developing solution or sprayed with the developing solution.

(9) Next, the surface of the interlayer resin insulating layer (the adhesive layer for electroless plating) having the via hole opening is roughened. Usually, roughening is performed by dissolving and removing heat-resistant resin particles present on the surface of the adhesive layer for electroless plating with an acid or an oxidizing agent. When performing the above acid treatment, phosphoric acid, hydrochloric acid, sulfuric acid, or an organic acid such as formic acid or acetic acid can be used, and it is particularly preferable to use an organic acid. This is because the metal conductor layer exposed from the via hole is hardly corroded when the roughening treatment is performed. For the above oxidation treatment, it is desirable to use chromic acid or permanganate (such as potassium permanganate). (10) Next, a thin electroless plating film is formed on the entire surface of the roughened interlayer insulating resin. This electroless plating film is preferably formed by electroless copper plating and has a thickness of 1 to 5 μm.
m, more preferably 2-3 μm.

(11) Further, a plating resist is provided thereon. As the plating resist, a commercially available photosensitive dry film or liquid resist can be used. Then, after applying a photosensitive dry film or applying a liquid resist, an ultraviolet exposure process is performed, and a developing process is performed with an alkaline aqueous solution.

(12) Next, after the substrate subjected to the above treatment is immersed in an electroplating solution, direct current electroplating is performed using the electroless plating layer as a cathode and the metal to be plated as an anode, and plating the openings for via holes. While filling
An upper conductor circuit is formed.

(13) Next, the plating resist is peeled off with a strong aqueous alkali solution, and etching is performed to remove the electroless plating layer, thereby forming the upper conductor circuit and the via hole into independent patterns. As the etching solution, a sulfuric acid / hydrogen peroxide aqueous solution, an aqueous solution of a persulfate such as ferric chloride, cupric chloride, or ammonium persulfate is used.

(14) Thereafter, if necessary, the steps (6) to (13) are repeated, and finally, a solder resist layer and solder bumps are formed, thereby completing the manufacture of the printed wiring board. Although the following method is based on the semi-additive method, a full additive method may be adopted.

In the method of manufacturing a printed wiring board according to the second aspect of the present invention, in the above step (2), a mask having an opening provided in a portion overlapping with the portion where the conductive circuit is not formed or in a narrower range than the portion is placed. Then, except that a layer of the resin filler is formed in the portion where the conductive circuit is not formed by applying the resin filler, the printed wiring board is manufactured in exactly the same manner as the method of manufacturing the printed wiring board of the first present invention. Manufacture boards.

When a layer of the resin filler is formed in a narrower area of the non-conductor-circuit-forming portion so that a gap is formed between the layer and the conductor circuit, then, for example, the resin filler layer is spread. Heating is performed under the conditions so that the gap between the conductor circuits is eliminated.

[0054]

The present invention will be described in more detail below. Example 1 A. Preparation of Adhesive for Electroless Plating (Adhesive for Upper Layer) 1) 25% acrylate of cresol novolac type epoxy resin (manufactured by Nippon Kayaku Co., Ltd., molecular weight: 2500) at a concentration of 80% by weight in diethylene glycol dimethyl ether (DMDG) 35 parts by weight of dissolved resin solution, photosensitive monomer (Aronix M315, manufactured by Toagosei Co., Ltd.) 3.1
5 parts by weight, antifoaming agent (S-65, manufactured by San Nopco) 0.5
Parts by weight and 3.6 parts by weight of N-methylpyrrolidone (NMP) were placed in a container and mixed by stirring to prepare a mixed composition.

2) Polyether sulfone (PES) 12
Parts by weight, 7.2 parts by weight of an epoxy resin particle (manufactured by Sanyo Kasei Co., polymer pole) having an average particle size of 1.0 μm and 3.09 parts by weight of an epoxy resin particle having an average particle size of 0.5 μm were placed in another container and stirred. After mixing, 30 parts by weight of NMP was further added and stirred and mixed by a bead mill to prepare another mixed composition.

3) Imidazole curing agent (Shikoku Chemicals, 2
E4MZ-CN), 2 parts by weight of a photopolymerization initiator (Irgacure I-907, manufactured by Ciba-Geigy), 0.2 parts by weight of a photosensitizer (DETX-S, manufactured by Nippon Kayaku) and NMP1. 5 parts by weight were placed in another container and mixed by stirring to prepare a mixed composition. And 1),
An adhesive for electroless plating was obtained by mixing the mixed compositions prepared in 2) and 3).

B. Preparation of adhesive for electroless plating (adhesive for lower layer) 1) 25% acrylate of cresol novolak type epoxy resin (manufactured by Nippon Kayaku Co., Ltd., molecular weight: 2500) is added to diethylene glycol dimethyl ether (DMDG) at a concentration of 80% by weight. 35 parts by weight of a dissolved resin solution, 4 parts by weight of a photosensitive monomer (manufactured by Toa Gosei Co., Aronix M315), 0.5 parts by weight of an antifoaming agent (S-65 manufactured by San Nopco) and N-methylpyrrolidone (NMP) 3 A mixed composition was prepared by placing 0.6 parts by weight in a container and mixing with stirring.

2) Polyether sulfone (PES) 12
14.49 parts by weight and epoxy resin particles (Polymer Pole, manufactured by Sanyo Kasei Co., Ltd.) having an average particle size of 0.5 μm
Transfer the parts by weight to another container, stir and mix.
30 parts by weight of P was added, and the mixture was stirred and mixed by a bead mill to prepare another mixed composition.

3) Imidazole curing agent (Shikoku Chemicals, 2
E4MZ-CN), 2 parts by weight of a photopolymerization initiator (Irgacure I-907, manufactured by Ciba-Geigy), 0.2 parts by weight of a photosensitizer (DETX-S, manufactured by Nippon Kayaku) and NMP1. 5 parts by weight were placed in another container and mixed by stirring to prepare a mixed composition. And 1),
An adhesive for electroless plating was obtained by mixing the mixed compositions prepared in 2) and 3).

C. Preparation of Resin Filler 1) 100 parts by weight of bisphenol F type epoxy monomer (manufactured by Yuka Shell Co., molecular weight: 310, YL983U), silane coupling agent coated on the surface, average particle size is 1.6 μm, maximum particle size Having a diameter of 15 μm or less
iO ₂ spherical particles (manufactured by Admatechs, CRS 110)
1-CE) 170 parts by weight and 1.5 parts by weight of a leveling agent (Perenol S4 manufactured by San Nopco) are placed in a container,
By stirring and mixing, the viscosity becomes 40 at 23 ± 1 ° C.
A resin filler of ５０50 Pa · s was prepared. In addition, as a curing agent, an imidazole curing agent (2E4M manufactured by Shikoku Chemicals Co., Ltd.)
(Z-CN) 6.5 parts by weight.

D. The steps (1) to (4) of the method for manufacturing a printed wiring board will be described with reference to FIGS. (1) 1 mm thick glass epoxy resin or BT (bismaleimide triazine) resin
A copper-clad laminate on which an 8 μm copper foil 8 was laminated was used as a starting material (see FIG. 1A). First, the copper-clad laminate was drilled, subjected to electroless plating, and etched in a pattern to form a lower conductor circuit 4 and through holes 9 on both surfaces of the substrate 1. At this time, the average length of the through hole was 1.2 mm.

(2) Through-hole 9 and lower conductor circuit 4
After the substrate on which was formed was washed with water and dried, NaOH (1
0 g / l), NaClO ₂ (40 g / l), Na ₃ PO
₄ A blackening treatment using an aqueous solution containing (6 g / l) as a blackening bath (oxidizing bath), NaOH (10 g / l), NaBH
₄ A reduction treatment was performed using an aqueous solution containing (6 g / l) as a reduction bath, and roughened surfaces 4a and 9a were formed on the entire surface of the lower conductor circuit 4 including the through holes 9 (see FIG. 1 (b)). .

(3) After preparing the resin filler described in the above C, within 24 hours after the preparation by the following method, the conductive circuit non-formed portion in the through hole 9 and on one side of the substrate 1 and the conductive circuit A layer of the resin filler 10 was formed on the outer edge portion of No. 4. That is, a mask having an opening at a portion overlapping with the through-hole 9 is placed on the substrate, and a resin filler is pressed into the through-hole using a rubber squeegee having a hardness of 80 ° to be filled therein. (FIG. 1C)
reference). Next, a mask having an opening at a portion overlapping with the conductor circuit non-formed portion and the outer edge portion of the conductor circuit 4 is placed on a substrate,
Using a rubber squeegee having a hardness of 80 °, a layer of the resin filler 10 was formed on the non-conductive portion and the outer edge of the conductive circuit 4, and dried at 100 ° C. for 20 minutes (FIG. 1D).
reference). The above hardness is measured by HAR made by Furisato Seiki Seisakusho
Using DNESS TESTER (A type hardness tester), JI
It was measured by a method according to SK6301. next,
A layer of the resin filler 10 was also formed on the conductor circuit non-formed portion on one side of the remaining substrate and on the outer edge of the conductor circuit 4 (FIG. 1).
(E)).

(4) One side of the substrate after the treatment of the above (3) was subjected to belt sander polishing using # 600 belt polishing paper (manufactured by Sankyo Rikagaku Co., Ltd.) to fill the resin formed on the outer periphery of the conductor circuit. The upper portion of the layer of the material 10 and the layer of the resin filler 10 formed on the portion where the conductive circuit was not formed were polished, and then buffing was performed to remove the scratches caused by the belt sander polishing. Such a series of polishing was similarly performed on the other surface of the substrate. If necessary, the lands 9a of the through holes 9 and the roughened surface 4a formed in the lower conductor circuit 4 may be planarized by etching before and after polishing. Thereafter, a heat treatment was performed at 100 ° C. for 1 hour and at 150 ° C. for 1 hour to completely cure the resin filler layer.

In this way, the surface portion of the resin filler 10 formed in the through hole 9 and the portion where the conductor circuit is not formed and the surface of the lower conductor circuit 4 are flattened, and the resin filler 10 and the side surfaces of the lower conductor circuit 4 are flattened. 4a is firmly adhered through the roughened surface, and the inner wall surface 9a of the through hole 9 and the resin filler 10
Was firmly adhered through the roughened surface to obtain an insulating substrate (see FIG. 1 (f)).

(5) Next, the substrate was alkali-degreased and soft-etched, and then treated with a catalyst solution comprising palladium chloride and an organic acid to provide a Pd catalyst and activate the catalyst.

Next, copper sulfate (3.9 × 10 ^-2 mol /
l), nickel sulfate (3.8 × 10 ^-3 mol / l), sodium citrate (7.8 × 10 ^-3 mol / l), sodium hypophosphite (2.3 × 10 ^-1 mol / l) ), Surfactant (Sufinol 465, manufactured by Nissin Chemical Industry Co., Ltd.)
(1.0 g / l), the substrate was immersed in an electroless copper plating bath of pH = 9 consisting of an aqueous solution containing 1 g of an aqueous solution, and after 1 minute of immersion, vibrated in the vertical and horizontal directions at a rate of once per 4 seconds. Cu-N on the surface of the land of the lower conductor circuit and the through hole
A roughened layer of a needle-shaped alloy made of iP was provided. Further, tin borofluoride (0.1 mol / l), thiourea (1.0 mol / l)
(mol / l) using a plating bath at a temperature of 35 ° C. and a pH of 1.2, and a Cu—Sn substitution reaction was performed to form a 0.3 μm thick Sn layer on the surface of the roughened layer.

(6) The adhesive for electroless plating for the lower layer described in B above (viscosity: 1.5 Pa ·
s) was applied using a roll coater within 24 hours after preparation, allowed to stand in a horizontal state for 20 minutes, and then dried at 60 ° C. for 30 minutes. Next, the adhesive for electroless plating (viscosity: 7 Pa · s) for the upper layer described in the above A was applied using a roll coater within 24 hours after preparation, and similarly left for 20 minutes in a horizontal state, Drying was performed at 60 ° C. for 30 minutes to form a 35 μm-thick electroless plating adhesive layer.

(7) A photomask film on which a black circle having a diameter of 85 μm is printed is brought into close contact with both surfaces of the substrate on which the adhesive layer for electroless plating is formed in the above (6), and 500 mJ / cm is applied by an ultra-high pressure mercury lamp. After exposure at ^two intensities, it was spray-developed with a DMDG solution. Thereafter, the substrate was further exposed at 3000 mJ / cm ² intensity using an ultra-high pressure mercury lamp,
Heat treatment at 100 ° C. for 1 hour, 120 ° C. for 1 hour, and 150 ° C. for 3 hours. 35 μm thick interlayer resin insulation with 85 μm diameter via hole openings with excellent dimensional accuracy equivalent to a photomask film. A layer was formed. Note that the tin plating layer was partially exposed in the opening serving as the via hole.

(8) The substrate in which the via hole opening is formed is immersed in a chromic acid aqueous solution (7500 g / l) for 19 minutes to dissolve and remove the epoxy resin particles present on the surface of the interlayer resin insulating layer, thereby removing the surface. It was roughened to obtain a roughened surface. Then, it was immersed in a neutralization solution (manufactured by Shipley) and washed with water. Further, by applying a palladium catalyst (manufactured by Atotech) to the surface of the substrate subjected to the surface roughening treatment, catalyst nuclei were attached to the surface of the interlayer insulating material layer and the inner wall surface of the via hole opening.

(9) Next, the substrate is immersed in an aqueous solution of electroless copper plating having the following composition, and has a thickness of 0.6 to 1.
An electroless copper plating film of 2 μm was formed. [Electroless plating aqueous solution] EDTA 0.08 mol / l Copper sulfate 0.03 mol / l HCHO 0.05 mol / l NaOH 0.05 mol / l α, α'-bipyridyl 80 mg / l PEG 0.10 g / L (polyethylene glycol) [Electroless plating conditions] at a liquid temperature of 65 ° C for 20 minutes

(10) A commercially available photosensitive dry film was attached to the electroless copper plating film, a mask was placed, and 100 mJ
/ Cm ² and developed with a 0.8% aqueous sodium carbonate solution to provide a plating resist having a thickness of 15 μm.

(11) Then, electroplating was performed on the non-resist-formed portions under the following conditions to form an electroplated film having a thickness of 15 μm. [Electroplating aqueous solution] sulfuric acid 2.24 mol / l copper sulfate 0.26 mol / l additive 19.5 ml / l (manufactured by Atotech Japan, capparaside HL) [electroplating conditions] current density 1 A / dm ² hours 65 minutes Temperature 22 ± 2 ℃

(12) Further, after the plating resist is stripped and removed with a 5% KOH aqueous solution, the electroless plating film under the plating resist is dissolved and removed by etching with a mixed solution of sulfuric acid and hydrogen peroxide, and the independent upper layer is removed. It was a conductor circuit.

(13) With respect to the substrate on which the conductor circuit is formed,
Perform the same treatment as in (5), and apply a 2 μm thick
An alloy roughened layer made of Cu-Ni-P was formed. (14) By repeating the above steps (5) to (13), a further upper conductive circuit was formed, and thereafter, a solder resist layer and solder bumps were formed to obtain a multilayer printed wiring board. FIG. 2 is a cross-sectional view schematically showing a printed wiring board after completion. 2 (2a, 2b) is an interlayer resin insulating layer, 5 is an upper conductor circuit, 7 is a via hole,
Reference numeral 1 denotes a roughened layer, 14 denotes a solder resist layer, 15 denotes a nickel plating film, 16 denotes a gold plating film, and 17 denotes a solder bump. FIG. 2 shows a case where only one upper-layer conductor circuit 5 is formed.

(Comparative Example 1) A mask having a through hole, a portion where a conductor circuit is not formed and a portion overlapping with the outer edge of the conductor circuit was placed on a substrate, and a through hole was formed at once using a rubber squeegee having a hardness of 80 °. A printed wiring board was obtained in the same manner as in Example 1, except that a layer of a resin filler was formed on the non-formed portion of the conductive circuit and the outer peripheral portion of the conductive circuit, and dried.

(Comparative Example 2) A resin filler layer was formed on the entire surface of the substrate on which the conductive circuit was formed in the step (3) by using the conventional method. A printed wiring board was obtained. As described above, for the multilayer printed wiring boards obtained in Example 1 and Comparative Examples 1 and 2, the presence or absence of the resin residue on the conductive circuit and the presence or absence of the adhesion of foreign matter were visually determined. After the formation of the solder bumps, the terminals for continuity inspection were brought into contact with the solder bumps on both surfaces of the substrate, and the presence or absence of continuity between the solder bumps was measured. In addition, 125 ° C
After performing a heat cycle test under conditions of 3 minutes at −55 ° C. for 3 minutes 1000 times, the printed wiring board is cut,
The cross section was observed using a 100 × optical microscope, and the presence or absence of peeling of the interlayer resin insulating layer and destruction of the conductor circuit was examined. The results are shown in Table 1 below.

[0078]

[Table 1]

As is clear from the results shown in Table 1, in Example 1, all the evaluation items were good, while in Comparative Examples 1 and 2, resin residue and adhesion of foreign matter were observed. In addition, peeling of the interlayer resin insulating layer and the conductor circuit has occurred.

[0080]

As described above, according to the present invention, a smooth substrate having a through hole and a conductor circuit can be formed, and an interlayer resin insulation layer and an upper layer conductor circuit can be formed thereon. Accordingly, it is possible to provide a method for manufacturing a printed wiring board that can be a printed wiring board having excellent connectivity and reliability.

[Brief description of the drawings]

FIGS. 1A to 1E are cross-sectional views showing a part of a manufacturing process of a printed wiring board according to the present invention.

FIG. 2 is a cross-sectional view schematically showing one example of the printed wiring board of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Substrate 2 Interlayer resin insulation layer (adhesive layer for electroless plating) 4 Lower-layer conductor circuit 4a Roughened surface 5 Upper-layer conductor circuit 7 Via hole 8 Copper foil 9 Through hole 9a Roughened surface 10 Resin filler 11 Roughened layer 14 Solder resist layer 15 Nickel plating film 16 Gold plating film 17 Solder bump

 ──────────────────────────────────────────────────続 き Continuing from the front page (72) Inventor Hironori Tanaka 1-1, Ibigawa-cho, Ibi-gun, Gifu Prefecture Inside the Ogaki-Kita Plant F-term in the Ogaki Plant of Shikisha Co., Ltd. (reference)

Claims (5)

[Claims] 1. A through hole and a conductor circuit are formed, and an opening is provided in a portion overlapping a conductor circuit non-formed portion and a conductor circuit outer edge portion on an insulating substrate in which the through hole is filled with a resin filler. A method for manufacturing a printed wiring board, comprising: placing a mask and applying a resin filler to form a layer of a resin filler on a non-conductive-circuit-forming portion and an outer edge of the conductive circuit. 2. A through-hole and a conductor circuit are formed, and an opening is provided on a portion of the insulating substrate in which the through-hole is filled with a resin filler, at a portion overlapping with a portion where a conductor circuit is not formed or in a narrower range than the portion. A method for manufacturing a printed wiring board, comprising: forming a layer of a resin filler in a portion where a conductive circuit is not formed by placing a mask that has been placed and applying a resin filler. 3. A method for manufacturing a printed wiring board, comprising: forming a resin insulating layer on an insulating substrate on which a through hole and a conductive circuit are formed, through at least the following steps (a) to (e). Method. (A) a step of filling the through hole with a resin filler and drying; (b) a step of forming a layer of the resin filler on an insulating substrate using the method according to claim 1 or 2;
(C) drying the resin filler layer formed in the step (b), (d) polishing the dried resin filler layer, and (e) curing the polished resin filler layer. Process 4. The method according to claim 3, wherein a roughened surface of the conductive circuit is flattened by etching before or after the step (d). 5. The thickness of an insulating layer constituting an insulating substrate is as follows:
The method for producing a printed wiring board according to claim 1, 2, 3, or 4, wherein the thickness is 0.5 to 1.5 mm.