JP2000328256A - Electroless plating liquid and production of printed wiring board using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electroless plating liquid capable of forming a covering layer so as to keep a ruggedness of a roughened surface as it is, without short- circuiting conductor circuits to each other due to the occurrence of abnormal precipitation and whiskers between the conductor circuits at the time of covering the conductor circuit on which the roughened surface is formed. SOLUTION: This electroless plating liquid is used after (1) forming the conductor circuit 4 on an insulating substrate, executing roughening treatment to the conductor circuit and forming the roughened surface thereon, or after (2) forming the conductor circuit of plural layers with interposed interlayer insulating layers on the insulating substrate, executing roughening treatment to the conductor circuit formed on the uppermost layer and forming the roughened surface thereon in order to form the covering layer 4b on the roughened surface which is formed in (1) of (2). In such a case, at least metallic salt, complex salt, reducing agent and surfactant are compounded in the electroless plating liquid.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electroless plating solution capable of forming a coating layer without flattening the surface of a conductor circuit having a roughened surface, and the electroless plating solution. And a method of manufacturing a printed wiring board including a step of coating a conductive circuit using the method.

[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 to which the copper foil is attached, 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 surface by electroless plating or etching, forming an insulating resin layer on the conductor circuit having the roughened surface, performing exposure and development processing to form a via hole opening, and then UV After curing and main curing, an interlayer resin insulating layer is formed. Furthermore, after performing a roughening formation process on 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. After the plating resist is removed, etching is performed to form a conductor circuit connected to the lower conductor circuit by via holes. After repeating this, finally form a solder resist layer to protect the conductor circuit, print solder paste on the part where the opening is exposed for connection with the conductor circuit, and form solder bumps Thereby, a build-up multilayer printed wiring board is obtained.

In the process of manufacturing such a multilayer printed wiring board, a roughened surface is formed on the surface of the conductive circuit by electroless plating, etching, or the like, and then the conductive circuit having the roughened surface is oxidized. For example, in order to prevent the dissolution of the protective film, a protective film is formed using an electroless plating solution containing a tin salt.

For example, according to Japanese Patent Application Laid-Open No. Hei 9-130050, the surface of a lower conductive circuit on which a roughened layer made of a Cu—Ni—P alloy is formed is made of a metal having a higher ionization tendency than titanium and less than titanium. By covering with a kind or more, the lower conductive circuit is protected from a roughening liquid such as chromic acid and permanganic acid and a soft etching liquid used in the roughening step of the interlayer resin insulating layer having an opening formed after this step. To prevent halo (peeling) of the interlayer resin insulating layer due to discoloration or dissolution of the resin.

[0006]

However, when a conventional electroless plating solution is used to cover a conductor circuit having a roughened surface with an electroless plating solution, depending on the shape of the formed unevenness, The following inconveniences occur.
That is, when irregularities are formed by etching or the like,
Alternatively, when a roughened surface having an uneven shape whose height is not so high as about 1 μm is formed, as shown in FIG. 17, the coating layer 21a formed on the conductive circuit 21 having the uneven shape is
The height of the unevenness is almost completely eliminated by filling the concave portion, or as shown in FIG. 18A, the coating layers formed on the convex portion are connected to each other to form a bridge-shaped coating layer 21a. There is a problem that the adhesion of the interlayer insulating layer formed on the conductor circuit is reduced.

Further, as shown in FIG. 18B, when the bridge-like coating layer 21a is formed, the gap 22 is formed in the concave portion.
Is formed, so that a roughening solution or an etching solution used in the step of roughening the interlayer insulating layer 23 enters the gaps 22 to dissolve a part of the conductor circuit 21 or to form a conductor with the interlayer insulating layer 23 having low adhesion. There is also a problem that the etchant penetrates into the circuit 21 and the interlayer insulating layer 23 is peeled off.

Further, due to impurities such as metals existing on the resin surface between the conductor circuits, abnormal precipitation 24 occurs on the resin surface as shown in FIG. 19, or as shown in FIG. There was also a problem that whiskers (whisker-like precipitates) 25 grew on the coating layer and the conductor circuits 21 were short-circuited.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to provide a method for coating a conductor circuit having a roughened surface with the occurrence of abnormal deposition or whisker between the conductor circuits. An electroless plating solution capable of forming a coating layer so as to maintain the uneven shape of the roughened surface without causing a short circuit between the conductor circuits, and a conductor circuit using the electroless plating solution. An object of the present invention is to propose a method of manufacturing a printed wiring board that can form a printed wiring board having excellent adhesion to an interlayer insulating layer formed thereon by forming a coating layer thereon.

[0010]

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 electroless plating solution of the present invention is obtained by (1) forming a conductor circuit on an insulating substrate and subjecting the conductor circuit to a plating treatment or an etching treatment to perform a roughening formation treatment, After forming the surface, or (2) forming a conductor circuit of multiple layers with an interlayer insulating layer interposed on the insulating substrate, and plating or etching the conductor circuit formed on the uppermost layer After forming a roughened surface by performing a roughening forming process by
An electroless plating solution used for forming a coating layer on the roughened surface formed in (1) or (2) above, wherein at least a metal salt, a complexing agent, a reducing agent, a surfactant and Is blended.

The metal salt contained in the electroless plating solution of the present invention is preferably at least one selected from the group consisting of tin salts, zinc salts, nickel salts, cobalt salts, thallium salts and lead salts. . Further, the surfactant is preferably at least one selected from the group consisting of polyethylene glycol, polypropylene oxide and polyethylene oxide.

In the electroless plating solution, the concentration of the metal salt is 0.01 to 3 mol / l, the concentration of the complexing agent is 0.1 to 2 mol / l, and the concentration of the reducing agent is 0.1 to 2 mol / l. Is preferably 1 to 80 g / l, and the concentration of the surfactant is preferably 0.1 to 10 g / l.

It is preferable that the electroless plating solution further contains gelatin in addition to the metal salt and the like, and the concentration thereof is preferably 100 to 2000 mg / l.

The method of manufacturing a printed wiring board according to the present invention is a method of manufacturing a printed wiring board in which a conductor circuit comprising a plurality of layers with an interlayer insulating layer interposed therebetween is formed on an insulating substrate. After performing a roughening formation process to form a roughened surface and forming a coating layer on the roughened surface using the above-described electroless plating solution, the substrate surface including the conductor circuit on which the coating layer is formed is interlayer-bonded. It is characterized by being coated with an insulating material.

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION The electroless plating solution of the present invention comprises (1)
After forming a roughened surface by forming a conductive circuit on the insulating substrate, performing a roughening process by performing a plating process or an etching process on the conductive circuit, or
(2) Forming a plurality of conductive circuits on an insulating substrate with an interlayer insulating layer interposed therebetween, and subjecting the conductive circuit formed on the uppermost layer to plating or etching to perform a roughening process. After forming the roughened surface, (1) or
(2) An electroless plating solution used for forming a coating layer on the roughened surface formed in (2), wherein at least a metal salt, a complexing agent, a reducing agent, and a surfactant are blended. It is characterized by the following.

Since the above-mentioned electroless plating solution contains the above-mentioned compound, it has excellent followability to the shape of the roughened surface,
As shown in FIG. 1, for example, since the coating film 4b is formed almost uniformly along the roughened surface formed in the lower conductive circuit 4, the shape of the unevenness of the roughened surface before coating is maintained as it is. Is done. Therefore, the adhesion between the interlayer insulating layer and the conductor circuit is excellent. Further, since no abnormal deposition or whisker is generated between the conductor circuits, a short circuit between the conductor circuits can be prevented.

Further, when the electroless plating solution further contains gelatin, the deposition reaction of the plating film is appropriately suppressed, so that the electroless plating solution is formed along the roughened surface formed in the lower conductor circuit 4. A uniform coating film is formed, and the shape of the irregularities on the roughened surface before coating is maintained as it is.

Depending on the plating conditions and the conditions of the substrate to be plated, some abnormal deposition may occur, but even in such a case, the width of the conductor layer protruding from the conductor circuit is at most about 1 μm. So the conductor circuit (wiring)
There is no short circuit between them. Even when whiskers are generated, their length is at most about 1 μm, and there is no short circuit between the conductor circuits (wirings).

The method of manufacturing a printed wiring board according to the present invention is a method of manufacturing a printed wiring board for forming a conductive circuit comprising a plurality of layers with an interlayer insulating layer interposed therebetween on an insulating substrate. After performing a forming treatment to form a roughened surface and forming a coating layer on the roughened surface using the electroless plating solution, the substrate surface including the conductor circuit on which the coating layer is formed is formed of an interlayer insulating material. It is characterized by coating.

In the method for manufacturing a printed wiring board of the present invention, since the coating layer is formed on the roughened surface using the above electroless plating solution, the coating film is formed almost uniformly along the roughened surface. As a result, it is possible to maintain the uneven shape of the roughened surface before coating as it is, and to manufacture a printed wiring board having excellent adhesion between the conductor circuit and the interlayer insulating layer formed thereon.

First, the electroless plating solution of the present invention will be described. The electroless plating solution of the present invention contains at least a metal salt, a complexing agent, a reducing agent, and a surfactant.

The metal salt is not particularly restricted but includes, for example, tin salts, zinc salts, nickel salts, cobalt salts, thallium salts, lead salts and the like. These salts may be used alone or in combination of two or more. Examples of the tin salt include tin borofluoride, tin chloride, potassium stannate (sodium stannate), tin sulfate and the like.

Examples of the zinc salt include zinc chloride,
Examples include zinc bromide and zinc iodide. Examples of the nickel salt include nickel chloride and nickel sulfate. Examples of the cobalt salt include cobalt chloride. Examples of the thallium salt include thallium chloride, and examples of the lead salt include lead chloride and lead nitrate.

The concentration of the metal salt is not particularly limited.
0.01 to 3 mol / l is desirable. When the concentration of the metal salt is less than 0.01 mol / l, a portion where the coating layer is not formed may occur, and when it exceeds 3 mol / l, a uniform coating layer may not be formed. A more desirable concentration is from 0.03 to 0.1 mol / l.

Examples of the complexing agent include thiourea,
Thiomalic acid, thiourea derivatives and the like. The concentration of the complexing agent is not particularly limited, but may be 0.1 to 2
mol / l is desirable. The concentration of the complexing agent is 0.1 m
If it is less than ol / l, the deposition rate of the plating is too slow.
The recesses on the roughened surface may be buried and the roughened surface may be flattened. If it exceeds 2 mol / l, the deposition rate of the plating is too fast, so that a coating layer is formed on the recessed portions on the roughened surface. And the coating layer may be non-uniform. A more desirable concentration is 0.3 to 1 mol / l.

Examples of the reducing agent include sodium hypophosphite, formaldehyde, sodium borohydride, hydrazine, dimethylamine borane and the like. By incorporating the reducing agent, it is possible to prevent the conductor circuit from being oxidized by the plating solution. Therefore, it is possible to prevent copper and the like contained in the conductor layer from being eluted into the plating solution during plating. The concentration of the reducing agent is not particularly limited.
~ 80 g / l is desirable. The concentration of the reducing agent is 1 g / l
If it is less than 10, the oxidation of the conductor circuit cannot be prevented, and copper or the like may be eluted. Even if it exceeds 80 g / l, the effect of preventing the oxidation of the conductor circuit hardly changes.
A more desirable concentration is 10 to 40 g / l.

The surfactant includes, for example, polyethylene glycol (PEG), polypropylene oxide, polyethylene oxide and the like. Of these, polyethylene glycol is preferred, and those having a molecular weight of ♯600 to ♯10,000 are preferred. Is more preferred. By blending the above surfactant, an electroless plating solution having excellent followability to the shape of the roughened surface can be obtained. In addition, water-soluble polyethylene glycol can slow down the plating deposition reaction and improve the gloss of the formed electroless plating film. The above-mentioned surfactants may be used alone or in combination of two or more.

The concentration of the surfactant is not particularly limited, but is preferably 0.1 to 10 g / l. If the amount of the surfactant is less than 0.1 g / 1, the throwing power becomes poor and the thickness of the plating film may vary depending on the location. Since the glossiness differs depending on the location of the circuit, a problem may occur in which the conductor circuit on which the new coating layer is formed is deteriorated in a later step. A more desirable concentration is 0.5 to
2 g / l.

When the concentration of each of the components to be mixed with the electroless plating solution is within the above range, the electroless plating solution is preferably a mixed solution containing an organic acid and a cupric complex, or sulfuric acid. Electroless plating solution used when forming a coating layer on a roughened surface formed by an etching process using a mixed solution containing hydrogen and hydrogen peroxide or a mixed solution containing sulfuric acid, hydrogen peroxide and halogen. Are suitable. Usually, the roughness of the roughened surface formed by the etching solution is not so large, but in the electroless plating solution in which the concentration of the compound is in the above range, a more uniform and thin coating layer is formed along the unevenness of the roughened surface. Is formed.

The electroless plating solution of the present invention may contain gelatin. The above-mentioned gelatin is a protein in which collagen is irreversibly converted to water-soluble by boiling in water, and denatured by breaking the secondary structure of collagen molecules due to cleavage of salt bonds and hydrogen bonds between peptide chains. Is preferred. This gelatin is obtained by boiling the aqueous solution for a long time to shorten the peptide chain, does not gel even when cooled, and dissolves in warm water to form a highly viscous sol. Further, depending on the production method, an acidic or alkaline product can be obtained. The gelatinous sol can be added to the plating solution to adjust the plating deposition state.

Further, by selecting the types and amounts (concentrations) of the gelatin and the surfactant, the deposition state of the electroless plating film can be more easily controlled, and abnormal deposition between the conductor circuits can be achieved. And whiskers can be further prevented, and the coating layer can be formed uniformly along the uneven shape of the conductor circuit.

The concentration of the gelatin is not particularly limited, but is preferably 100 to 2000 mg / l. If the concentration of gelatin is less than 100 mg / l, the above-mentioned problems such as generation of whiskers may be caused due to the inability to control the precipitation rate. In some cases, an uncoated portion may occur, or the deposition of plating may stop.

When the above-mentioned gelatin is mixed with the electroless plating solution of the present invention, the mixing ratio of the above-mentioned gelatin and the above-mentioned surfactant is 0.5-2.0: 0.5-2.0 by weight ratio. Is preferable, and 1: 1 is more preferable. By adding the gelatin and the surfactant in a ratio of about 1: 1,
It is easy to control the rate of deposition, it is easy to maintain the stability of the plating solution, and it is possible to prevent the above-mentioned disadvantages from occurring.

The electroless plating solution used in the present invention includes:
In particular, those containing a tin salt or a zinc salt are preferable, and displacement plating can be performed by using these metal salts. These plating solutions are also effective for forming a roughened layer on a conductor circuit by electroless plating.

Specifically, examples of the electroless plating solution containing a tin salt include tin borofluoride and thiourea or tin chloride and thiourea with the above-mentioned reducing agent such as sodium hypophosphite, polyethylene glycol and the like. Those containing a surfactant and, if necessary, gelatin.

Examples of the electroless plating solution containing the zinc salt include metal salts such as zinc chloride, zinc bromide and zinc iodide, a complexing agent represented by thiourea, and various other additives. Are blended. When using an electroless plating solution containing a zinc salt, whiskers may be generated with the zinc salt alone.Therefore, a plating solution containing a lead salt, a copper salt, an antimony salt or the like is prepared, and as an alloy. It is desirable to precipitate.

If the temperature at the time of performing the plating treatment is 20 ° C. or lower, the deposition rate becomes too slow because the reactivity is suppressed. Therefore, the temperature when performing the plating process is
The temperature is preferably from 25 to 60C, more preferably from 25 to 50C, even more preferably from 25 to 40C. If the temperature is in the range of 25 to 60 ° C., there is no problem in the deposition rate, the deposition state, and the characteristics of the plating film, and the plating film can be formed stably. If the temperature exceeds 60 ° C., the stability of the deposition rate is lacking, and the surfactant may be deteriorated or deteriorated by heat in some cases.

The processing time for performing the plating process is not particularly limited, but is preferably 30 seconds to 5 minutes. If the above treatment time is less than 30 seconds, a portion where the coating layer is not formed may occur. On the other hand, if it exceeds 5 minutes, a uniform coating layer may not be formed or the concave portion of the roughened surface may be filled. Sometimes. In addition, since the deposition rate of plating can be adjusted by the concentration of the composition of the electroless plating solution,
The above processing time may be selected in consideration of the concentration of the compound.

The roughened layer is made of copper (for example, Cu-Ni-
(P alloy) or the like, in order to improve the wettability of the electroless plating solution, a solution containing about 10% by weight of a reducing agent or an oxidizing agent as a pretreatment solution, or 10 v
ol% concentration of sulfuric acid, borofluoric acid, pyrophosphoric acid, etc., and immersing the substrate with the roughened layer in this pretreatment liquid, and then treating it with an electroless plating solution, the coating layer due to unreacted Loss can be prevented.

The electroless plating solution of the present invention can be used to form a porous roughened layer made of a Cu—Ni—P alloy on a conductor circuit, an etching solution containing an organic acid and a cupric complex, or sulfuric acid. This is particularly effective when a roughened surface is formed on a conductor circuit using an etching solution containing hydrogen and hydrogen peroxide or an etching solution containing sulfuric acid, hydrogen peroxide and halogen.

Next, a method for manufacturing a printed wiring board using the electroless plating solution of the present invention will be described. (1) In the method for manufacturing a printed wiring board of the present invention, first, a substrate having a conductive circuit formed on a surface of an insulating substrate is prepared.

As the insulating substrate, a resin substrate is desirable. Specifically, for example, a glass epoxy substrate, a polyester substrate, a polyimide substrate, a bismaleimide-triazine resin substrate, a fluororesin substrate, a ceramic substrate, a copper-clad laminate, etc. Is mentioned. At this time, a through hole may be formed in the insulating substrate by a drill, a laser, or the like, and the surface conductive film and the through hole may be formed by performing electroless plating on the wall surface of the through hole and the surface of the copper foil. Copper plating is preferred as the electroless plating.

After this electroless plating, a roughening treatment is usually performed on the inner wall of the through hole and the surface of the electrolytic plating film.
Examples of the roughening forming treatment method include blackening (oxidation) -reduction treatment, a mixed aqueous solution of an organic acid and a cupric complex, a mixed aqueous solution containing sulfuric acid and hydrogen peroxide, and a mixed aqueous solution of sulfuric acid and hydrogen peroxide. Spray treatment with mixed aqueous solution containing halogen, Cu
-Ni-P needle-like alloy plating. In some cases, heat treatment for removing extra components (moisture, solvent, and the like) of the substrate having the roughened surface may be performed.

Examples of the organic acid in the mixed aqueous solution of the above organic acid and the cupric complex include formic acid, acetic acid, propionic acid, butyric acid, valeric acid, caproic acid, acrylic acid, crotonic acid, oxalic acid, malonic acid, Succinic acid, glutaric acid, maleic acid, benzoic acid, glycolic acid, lactic acid, malic acid,
Sulfamic acid and the like. These may be used alone or in combination of two or more. In the mixed aqueous solution, the content of the organic acid is desirably 0.1 to 30% by weight. This is because the solubility of the oxidized copper can be maintained and the stability of the catalyst can be ensured.

The cupric complex is preferably an azole cupric complex. This cupric complex of azoles acts as an oxidizing agent for oxidizing metallic copper and the like. As the azoles, for example, diazole, triazole,
Tetrazole and the like. Among these, imidazole, 2-methylimidazole, 2-ethylimidazole, 2-ethyl-4-methylimidazole, 2-phenylimidazole, and 2-undecylimidazole are desirable. In the mixed aqueous solution, the content of the cupric complex is desirably 1 to 15% by weight. This is because it is excellent in solubility and stability, and can also dissolve noble metals such as Pd constituting the catalyst core.

The treatment by the Cu—Ni—P needle-like alloy plating includes, for example, the following method. That is, copper sulfate (1 to 40 g / l), nickel sulfate (0.1 to 6.0 g / l), citric acid (10 to 20 g / l)
l), sodium hypophosphite (10-100 g / l),
Boric acid (10 to 40 g / l) and a surfactant (Surfynol 465 manufactured by Nissin Chemical Industry Co., Ltd.) (0.01 to 10
g / l) and a method of performing electroless plating in an electroless plating bath with PH = 9. In addition, you may add a complexing agent and an additive to the said electroless plating bath in addition to the said compound.

(2) Next, an etching resist having a conductor circuit shape is formed on the substrate subjected to the electroless plating, and the conductor circuit is formed by performing etching. Next, a resin filler is applied to the surface of the substrate on which the conductive circuit is formed, dried to a semi-cured state, then polished, the resin filler layer is ground, and the upper part of the conductive circuit is also ground. Then, both main surfaces of the substrate are flattened. Thereafter, the layer of the resin filler is completely cured.

(3) Next, a roughening process of the conductor circuit is performed. Examples of the roughening forming method include a method of forming a needle-like or porous roughening layer made of a Cu—Ni—P alloy on a conductive circuit by electroless plating, and a method of blackening (oxidizing).
Conductive circuits such as a reduction treatment method, a mixed aqueous solution of an organic acid and a cupric complex, an aqueous mixed solution containing sulfuric acid and hydrogen peroxide, and a mixed aqueous solution containing sulfuric acid, hydrogen peroxide and halogen are used. There is a method of forming a roughened surface by etching.

(4) Then, at least a metal salt such as a tin salt or a zinc salt, a complexing agent, and a reducing agent are formed on the roughened surface formed by forming a roughened layer on the conductor circuit or etching the conductor circuit. A coating layer is formed by using the electroless plating solution of the present invention containing an agent and a surfactant. The thickness of the coating layer is preferably 0.01 to 2 μm. When the thickness of the coating layer is 0.
When the thickness is less than 01 μm, the coating layer is too thin, and a portion where the plating film is not formed occurs on the surface of the conductor circuit. On the other hand, when the thickness of the coating layer exceeds 2 μm, a uniform coating layer is formed. This makes it difficult to form the interlayer resin insulating layer having excellent adhesion on the conductor circuit. More preferably, the thickness of the coating layer is 0.1.
01 to 1 μm, and more preferably the thickness of the coating layer is 0.1 μm.
03 to 0.5 μm.

(5) Thereafter, an interlayer resin 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.

When forming the interlayer insulating layer, an adhesive 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 size of 10 μm or less, and (b) an average particle size 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) an average particle diameter of 2 to 10 μm on the surface of the heat-resistant resin powder. Pseudo particles obtained by adhering at least one of a heat-resistant resin powder or an inorganic powder having a particle diameter of 2 μm or less, (e) a heat-resistant resin powder having an average particle diameter of 0.1 to 0.8 μm and an average particle diameter It is desirable to use a mixture with a heat-resistant resin powder having a particle size of more than 0.8 μm and less than 2 μm, and (f) a heat-resistant resin powder having an average particle size of 0.1 to 1.0 μm. This is because these can form a more complicated anchor.

The height 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, phenoxy resin and the like can be used. The mixing ratio of the thermosetting resin (photosensitive resin) and the thermoplastic resin is as follows: thermosetting resin (photosensitive resin) / thermoplastic resin = 95/5 to 50 /
50 is desirable. 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 from 5 to 50% by weight, more preferably from 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.

The interlayer resin insulating layer is made of a polyphenylene ether resin, in addition to the adhesive for electroless plating.
It can also be formed using a thermoplastic elastomer resin, a polyolefin resin, a fluorine resin, a triazine resin, or the like. Examples of the polyphenylene ether resin include a thermoplastic polyphenylene ether resin having a repeating unit represented by the following chemical formula (1) and a thermosetting polyphenylene ether resin having a repeating unit represented by the following chemical formula (2). Can be

[0058]

Embedded image

(In the formula, n represents an integer of 2 or more.)

[0060]

Embedded image

(Wherein, m represents an integer of 2 or more. R ¹ and R ² represent a methylene group, an ethylene group or a —C
Represents H ₂ —O—CH ₂ —, both of which may be the same or different. )

The thermoplastic polyphenylene ether resin having a repeating unit represented by the above chemical formula (1) has a structure in which a methyl group is bonded to a benzene ring, but the polyphenylene ether which can be used in the present invention. The resin may be a derivative in which the above-mentioned methyl group is substituted with another alkyl group such as an ethyl group, or a derivative in which hydrogen of a methyl group is substituted with fluorine.

The thermoplastic elastomer resin is not particularly restricted but includes, for example, styrene-based thermoplastic elastomers, olefin-based thermoplastic elastomers, urethane-based thermoplastic elastomers, polyester-based thermoplastic elastomers, polyamide-based thermoplastic elastomers, -Polybutadiene-based thermoplastic elastomers, PVC-based thermoplastic elastomers, fluorine-based thermoplastic elastomers, and the like. Among these, olefin-based thermoplastic elastomers and fluorine-based thermoplastic elastomers are desirable from the viewpoint of excellent electrical properties.

The above-mentioned polyolefin resin is not particularly restricted but includes, for example, polyethylene, polypropylene, polyisobutylene, polybutadiene, polyisoprene, cycloolefin resin and copolymers of these resins.

Examples of commercially available products of the polyolefin resin include, for example, 1592 (trade name, manufactured by Sumitomo 3M Limited). Commercially available thermoplastic polyolefin resins having a melting point of 200 ° C. or higher include, for example, TPX (trade name: 240 ° C., manufactured by Mitsui Petrochemical Co., Ltd.) and SPS (trade name, manufactured by Idemitsu Petrochemical Co., Ltd.) Melting point 270 ° C.). Among them, cyclo-dielectric materials have low dielectric constant and dielectric loss tangent, are unlikely to cause signal delay and signal error even when a high-frequency signal in the GHz band is used, and are excellent in mechanical characteristics such as rigidity. Olefin resins are desirable.

As the above cycloolefin resin, 2
Homopolymers or copolymers of monomers comprising -norbornene, 5-ethylidene-2-norbornene or derivatives thereof are desirable. As the above derivative, the above 2-
Examples include those in which an amino group for forming a crosslink, a maleic anhydride residue, or a maleic acid-modified one is bonded to a cycloolefin such as norbornene. Examples of monomers for synthesizing the copolymer include ethylene and propylene.

The cycloolefin resin may be a mixture of two or more of the above resins, or may contain a resin other than the cycloolefin resin. When the cycloolefin resin is a copolymer, it may be a block copolymer or a random copolymer.

The cycloolefin resin is desirably a thermosetting cycloolefin resin.
This is because by performing the heating to form the crosslinks, the rigidity is further increased and the mechanical properties are improved. The glass transition temperature (Tg) of the cycloolefin resin is 13
Desirably, the temperature is 0 to 200 ° C.

As the above cycloolefin resin, those already formed as a resin sheet (film) may be used, and a monomer or a low molecular weight polymer having a constant molecular weight may be used as a solvent such as xylene or cyclohexane. It may be in the state of an uncured solution dispersed in. In the case of a resin sheet, a so-called RCC (RESIN COATE
D COPER: resin-coated copper foil).

The cycloolefin resin may not contain a filler or the like, or may contain a flame retardant such as aluminum hydroxide, magnesium hydroxide, or a phosphate.

When the above polyolefin resin is used, melamine, phenol resin, epoxy resin, polyimide resin, fluororesin, PP
Organic fillers such as O and PPE may be blended. By blending the organic filler, for example, when forming the via hole opening by irradiating the interlayer resin insulating layer with a laser beam, the via hole opening having a desired shape can be favorably formed.

The content of the organic filler is preferably 5 to 60% by weight. The content of the organic filler is 5% by weight
When the content is less than the above, the content of the organic filler is too small, so that the above-mentioned role cannot be performed at the time of laser beam irradiation, and a non-through hole or the like having a desired shape may not be formed. On the other hand, when the content of the organic filler is 60
If the content is more than 10% by weight, the properties of the polyolefin resin are lost, and, for example, the dielectric constant may be too high. More preferred amount of the organic filler,
14 to 60% by weight.

Examples of the fluororesin include ethyl / tetrafluoroethylene copolymer resin (ETFE) and polychlorotrifluoroethylene (PCTFE).

When the interlayer resin insulating layer is formed by attaching the above-mentioned resin film, the interlayer resin insulating layer is formed using a device such as a vacuum laminator under reduced pressure or vacuum under a pressure of 2.0 to 10 kgf / kg. pressure of cm ^2,
It is desirable to perform pressure bonding at a temperature of 60 to 120 ° C., and then heat-curing the resin film. The heat curing may be performed after forming a via hole opening and a through hole described later.

The thickness of the interlayer resin insulating layer formed by using the manufacturing method of the present invention is not particularly limited.
0 μm is desirable. When the thickness is less than 5 μm, insulation between the vertically adjacent conductor circuits may not be maintained. On the other hand, when the thickness is more than 50 μm, when a non-through hole or the like is formed, resin residue may remain on the bottom thereof. It may be generated or the shape of the non-through hole or the like may be tapered toward the bottom.

The interlayer resin insulation layer desirably has a dielectric constant at 1 GHz of 3.0 or less and a dielectric loss tangent of 0.01 or less. The dielectric constant is 2.4 to 2.
7 is more preferred. Examples of the resin having such a dielectric constant include a polyphenylene ether resin and a polyolefin resin. By using such a material having a low dielectric constant, it is possible to prevent a signal error due to a delay in signal propagation, a signal transmission loss, and the like.

(6) Next, while the interlayer insulating resin layer is cured, an opening for forming a via hole (hereinafter also referred to as a via hole opening) is provided in the interlayer resin resin layer. Opening of the interlayer insulating resin layer can be performed by laser processing, plasma processing, exposure and development processing, or the like. Specifically, for example, when the resin matrix of the adhesive for electroless plating is a thermosetting resin, it is performed using laser light or oxygen plasma, and when the resin matrix is a photosensitive resin, it is exposed and developed. Performed by 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. By curing the interlayer resin insulating layer formed on the conductor circuit having a roughened surface with a sufficient unevenness, an interlayer resin insulating layer having excellent adhesion to the conductor circuit can be formed.

As the laser used for performing the laser processing, for example, a carbon dioxide gas laser, an excimer laser,
V laser, YAG laser and the like can be mentioned. These lasers may be used in consideration of the material of the interlayer resin insulating layer, the shape of the via hole opening, and the like. Note that the laser treatment is preferably performed by irradiating a portion corresponding to a portion for forming a via hole opening with a laser beam through a mask provided with a through hole.

When forming the via hole openings, a large number of via hole openings can be formed at once by irradiating laser light with a hologram type excimer laser through a mask. Further, when the via hole opening is formed using a short-pulse carbon dioxide laser, the amount of resin remaining in the opening is small, and the damage to the resin at the periphery of the opening is small.

By irradiating a laser beam through an optical lens and a mask, a large number of via hole openings can be formed at once. This is because a plurality of portions can be simultaneously irradiated with laser light having the same intensity and the same irradiation angle through the optical lens and the mask.

The through hole formed in the mask is desirably a perfect circle in order to make the spot shape of the laser beam a perfect circle, and the diameter of the through hole is desirably about 0.1 to 2 mm. When the carbon dioxide laser is used, the pulse interval is desirably 10 ⁻⁴ to 10 ⁻⁸ seconds. The time for irradiating the laser for forming the opening is preferably 10 to 500 μsec.

When the opening for the via hole is formed by the laser beam, particularly when a carbon dioxide gas laser is used, desmearing is desirably performed. The desmear treatment can be performed using an oxidizing agent composed of an aqueous solution such as chromic acid and permanganate. In addition, oxygen plasma, CF ₄
It may be treated by a mixed plasma of oxygen and oxygen, corona discharge, or the like. The surface can also be modified by irradiating ultraviolet rays using a low-pressure mercury lamp. When a through hole is formed in a substrate on which an interlayer resin insulating layer is formed,
A through hole is formed using a drill having a diameter of 50 to 300 μm, a laser beam, or the like.

(7) Next, if necessary, the surface of the interlayer resin insulation layer (the adhesive layer for electroless plating) having the via hole opening is roughened. Usually, the roughening is performed by dissolving and removing the 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). Also, when the interlayer resin insulating layer is formed using a material other than the above-mentioned adhesive for electroless plating, a roughened surface can be formed using the above-mentioned acid or oxidizing agent. Further, a roughened surface may be formed by performing a plasma treatment or the like.

When the roughened surface is formed by using an acid after the roughening treatment of the surface of the interlayer resin insulating layer, the roughened surface is formed by using an aqueous solution such as an alkali and an oxidizing agent. It is preferable to neutralize the inside of the via hole opening or the like by using a neutralizing solution. By this operation, the acid and the oxidizing agent can be removed so that the next step is not affected.

After forming the via hole opening,
If necessary, at least a part of the coating layer exposed from the via hole opening may be removed. This is because when a via hole is formed on a conductor circuit having a coating layer made of a metal such as tin, the metal forming the coating layer and the metal forming the via hole are different types of metal. This is because the electric transmission speed is different and a signal delay or a signal error may occur in the covering layer portion.

Further, if the metal forming the coating layer and the metal forming the via hole are different metals, the heat between the metal forming the coating layer and the metal forming the via hole during heating or heat cycle. If stress is generated due to the difference in expansion coefficient and this stress is not relieved, peeling occurs at the contact between the via hole and the conductor circuit underneath, and the connection reliability of the via hole and the electrical This is because the connectivity may be reduced.

As a method for removing the coating layer exposed from the via hole opening, for example, 10 to 40% by weight
Alkaline solution containing acid and oxidizing agent, 10 to 40% by weight
And an etching treatment using a mixed solution of an acid and a peroxide.

Examples of the acid include hydrochloric acid, nitric acid, sulfuric acid, phosphoric acid, hydrofluoric acid, formic acid and the like. They are,
They may be used alone or in combination of two or more. Examples of the peroxide include hydrogen peroxide and potassium peroxide. These may be used alone,
Two or more kinds may be used in combination. Note that the coating layer formed using the electroless plating solution of the present invention is easily peeled off by an etching treatment using the above-mentioned acid, an alkaline solution containing an oxidizing agent, or a mixed solution containing an acid and a peroxide. Can be done.

(8) Next, a thin film conductor layer made of tin, zinc, copper, nickel, cobalt, thallium, lead, etc. is formed on the entire surface of the roughened interlayer insulating resin by electroless plating, sputtering, vapor deposition, or the like. I do. The thin film conductor layer may be a single layer or may be composed of two or more layers. Among these, a thin film conductor layer made of copper, copper, and nickel is desirable in consideration of electrical characteristics, economy, and the like. When the thin film conductor layer is formed by electroless plating, the thickness is preferably 0.3 to 5 μm,
0.5 to 1.2 μm is more preferable. When a roughened surface is not formed on the interlayer resin insulating layer, the thin film conductor layer is preferably formed by sputtering. In addition, when forming a thin film conductor layer by sputtering or vapor deposition, the thickness is preferably 0.1 to 1.0 μm.

(9) Further, a plating resist is formed on a part of the thin film conductor layer. As the plating resist, a commercially available photosensitive dry film or liquid resist can be used. Then, after a photosensitive dry film is attached or a liquid resist is applied, an exposure process using ultraviolet light or the like is performed, and a development process is performed using an alkaline aqueous solution.

(10) Then, after the substrate subjected to the above treatment is immersed in an electroplating solution, direct current electroplating is performed using the thin film conductor layer as a cathode and the metal to be plated as an anode, and the opening for the via hole is plated. While filling
An upper conductor circuit is formed in a portion where the plating resist is not formed.

(11) Then, the plating resist is peeled off with a strong aqueous alkali solution and then etched to remove the thin film conductor layer, thereby forming the upper conductor circuit and the via hole into independent patterns. Examples of the etching solution include a sulfuric acid / hydrogen peroxide aqueous solution, an aqueous solution of persulfate such as ammonium persulfate, sodium persulfate, and potassium persulfate, an aqueous solution of ferric chloride and cupric chloride, hydrochloric acid, nitric acid, and hot dilute sulfuric acid. Is used. Alternatively, a roughened surface may be formed simultaneously with etching between conductor circuits using an etching solution containing the above-described cupric complex and an organic acid.

(12) Thereafter, if necessary, the steps (3) to (11) are repeated to produce a substrate on which the conductor circuit and the interlayer resin insulating layer are sequentially laminated.

(13) Next, a solder resist layer is formed on the surface of the substrate including the uppermost conductive circuit, a solder pad is formed by opening the solder resist layer, and a solder paste is applied to the solder pad. Filling and reflowing form solder bumps. Then, on the external board connection surface,
By arranging pins and forming solder balls, PGA (Pin Grid Array) and BGA (Ball Grid Arr
ay).

The above-mentioned solder resist layer can be formed by using, for example, a solder resist composition comprising a polyphenylene ether resin, a polyolefin resin, a fluororesin, a thermoplastic elastomer, an epoxy resin, a polyimide resin, and the like. As a specific example, for example, the same resin as the resin used when forming the interlayer resin insulating layer and the like can be mentioned.

Examples of the solder resist composition other than those described above include, for example, a novolak-type epoxy resin (meth) acrylate, an imidazole curing agent, a bifunctional (meth) acrylate monomer, and a molecular weight of 500 to 50.
A paste-like fluid containing a polymer of about 00 (meth) acrylate, a thermosetting resin such as a bisphenol-type epoxy resin, a photosensitive monomer such as a polyvalent acrylic monomer, a glycol ether-based solvent, and the like. It is desirable that the viscosity is adjusted to 1 to 10 Pa · s at 25 ° C.

(Meth) of the novolak type epoxy resin
Examples of the acrylate include an epoxy resin obtained by reacting glycidyl ether of phenol novolak or cresol novolak with acrylic acid, methacrylic acid, or the like.

The bifunctional (meth) acrylic acid ester monomer is not particularly limited, and includes, for example, acrylic acid and methacrylic acid esters of various diols, and commercially available products manufactured by Nippon Kayaku Co., Ltd. R-604, PM
2, PM21 and the like.

The solder resist composition may contain an elastomer or an inorganic filler. By being blended with the elastomer, the formed solder resist layer can absorb or reduce the stress even when a stress acts on the solder resist layer due to the flexibility and rebound resilience of the elastomer. As a result, cracks and peeling can be suppressed from occurring in the manufacturing process of the multilayer printed wiring board and in the solder resist layer after mounting electronic components such as IC chips on the manufactured multilayer printed wiring board. Even when it occurs, the crack does not grow large.

The method of opening the solder resist layer includes, for example, a method of irradiating a laser beam and a method of exposure and development as in the method of forming an opening for a via hole.

When a photosensitive solder resist composition is used as the solder resist composition, after a solder resist layer is formed, a photoresist is placed on the solder resist layer, and exposed and developed. By performing the above, the solder resist layer can be opened.

The conductor circuit portion exposed by opening the solder resist layer is usually desirably covered with a corrosion-resistant metal such as nickel, palladium, gold, silver, and platinum. Specifically, nickel-gold, nickel-
It is desirable to form the coating layer with a metal such as silver, nickel-palladium, nickel-palladium-gold, and the like. The coating layer can be formed by, for example, plating, vapor deposition, electrodeposition, and the like, and among these, plating is preferable because of excellent uniformity of the coating layer.

Incidentally, a plasma treatment with oxygen, carbon tetrachloride, or the like may be performed as needed for a character printing step for forming product recognition characters or the like or for modifying the solder resist layer. Although the above method is based on the semi-additive method, a full additive method may be employed.

[0104]

The present invention will be described in more detail below. Example 1 A. Preparation of adhesive for electroless plating (adhesive for upper layer) (i) 25% acrylate of cresol novolac type epoxy resin (manufactured by Nippon Kayaku Co., Ltd., molecular weight: 2500) at a concentration of 80% by weight of diethylene glycol dimethyl ether (DMDG) 35 parts by weight of a resin solution dissolved in water, photosensitive monomer (Aronix M315, manufactured by Toa Gosei 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.

(Ii) Polyether sulfone (PES) 1
2 parts by weight, 7.2 parts by weight of an epoxy resin particle (manufactured by Sanyo Kasei Co., polymer pole) having an average particle diameter of 1.0 μm and 3.09 parts by weight of an epoxy resin particle having an average particle diameter of 0.5 μm were placed in another container, After stirring and mixing, 30 parts by weight of NMP was further added and stirred and mixed with a bead mill to prepare another mixed composition.

(Iii) 2 parts by weight of an imidazole curing agent (2E4MZ-CN, manufactured by Shikoku Chemicals), 2 parts by weight of a photopolymerization initiator (Irgacure I-907, manufactured by Ciba-Geigy), a photosensitizer (Nippon Kayaku) 0.2 parts by weight of DETX-S) and 1.5 parts by weight of NMP were placed in another container and mixed by stirring to prepare a mixed composition. Then, an adhesive for electroless plating was obtained by mixing the mixed compositions prepared in (i), (ii) and (iii).

B. Preparation of adhesive for electroless plating (adhesive for lower layer) (i) 25% acrylate of cresol novolac type epoxy resin (manufactured by Nippon Kayaku Co., Ltd., molecular weight: 2500) at a concentration of 80% by weight of diethylene glycol dimethyl ether (DMDG) 35 parts by weight of a resin solution, 4 parts by weight of a photosensitive monomer (manufactured by Toagosei Co., Aronix M315), 0.5 parts by weight of an antifoaming agent (S-65 manufactured by Sannopco) and N-methylpyrrolidone (NMP) 3.6 parts by weight were placed in a container and mixed by stirring to prepare a mixed composition.

(Ii) Polyether sulfone (PES) 1
2 parts by weight and epoxy resin particles (manufactured by Sanyo Chemical Industries,
14.4 having an average particle size of 0.5 μm
9 parts by weight were placed in another container and mixed with stirring.
30 parts by weight of MP was added and mixed by stirring with a bead mill to prepare another mixed composition.

(Iii) 2 parts by weight of an imidazole curing agent (2E4MZ-CN, manufactured by Shikoku Chemicals), 2 parts by weight of a photopolymerization initiator (Irgacure I-907, manufactured by Ciba Geigy), a photosensitizer (Nippon Kayaku) 0.2 parts by weight of DETX-S) and 1.5 parts by weight of NMP were placed in another container and mixed by stirring to prepare a mixed composition. Then, an adhesive for electroless plating was obtained by mixing the mixed compositions prepared in (i), (ii) and (iii).

C. Preparation of resin filler (i) 100 parts by weight of bisphenol F type epoxy monomer (manufactured by Yuka Shell Co., molecular weight: 310, YL983U),
SiO ₂ spherical particles having an average particle diameter of 1.6 μm and a maximum particle diameter of 15 μm or less (CRS 1101 manufactured by Adtec Co., Ltd.) having a surface coated with a silane coupling agent.
-CE) 170 parts by weight and 1.5 parts by weight of a leveling agent (Perenol S4 manufactured by San Nopco Co.) are placed in a container, and the mixture is stirred and mixed to have a viscosity of 40 to 40 at 23 ± 1 ° C.
A resin filler of 50 Pa · s was prepared. As the curing agent, an imidazole curing agent (2E4MZ manufactured by Shikoku Chemicals Co., Ltd.)
-CN) 6.5 parts by weight.

D. Manufacturing method of printed wiring board (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. 2A). First, the copper-clad laminate was drilled, subjected to an electroless plating treatment, and etched in a pattern to form a lower conductor circuit 4 and a through hole 9 on both surfaces of the substrate 1.

(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 reducing 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. 2 (b)). .

(3) After preparing the resin filler described in C above, within 24 hours after the preparation by the following method, the resin filler 1 in the through hole 9 and between the lower conductor circuits 4 is prepared.
0 (see FIG. 2 (c)).
At this time, as a coating method, a printing method using a squeegee was adopted. In the first printing coating, the through holes 9 were mainly filled and dried at 100 ° C. for 20 minutes. Also,
In the second printing application, the recesses mainly formed by the formation of the lower conductive circuit 4 were filled and dried at 100 ° C. for 20 minutes.

(4) One surface of the substrate after the treatment of the above (3) is subjected to belt sanding using # 600 belt abrasive paper (manufactured by Sankyo Rikagaku Co., Ltd.) to form the surface of the lower conductor circuit 4 and the through holes 9. Was polished so that the resin filler did not remain on the land surface, and then buffed 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. 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 layer of the resin filler 10 and the surface of the lower conductor circuit 4 formed in the through holes 9 and the portions where the conductor circuit is not formed 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. 2D).

(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 11 of a needle-shaped alloy made of iP was provided (FIG. 3).
(See (a)).

(6) Further, tin borofluoride (0.1 mol
l / l), thiourea (1.0 mol / l), gelatin (1000 mg / l), polyethylene glycol (1000 mg / l) as a surfactant at a temperature of 35 ° C,
Using a tin-substituted plating solution having a pH of 1.2, a Cu-Sn substitution reaction was performed, and a 0.3 μm-thick Sn layer was provided on the surface of the roughened layer. However, this Sn layer is not shown.

(7) The lower layer electroless plating adhesive (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, After drying at 60 ° C. for 30 minutes, a 35 μm-thick electroless plating adhesive layer 2
a and 2b were formed (see FIG. 3B).

(8) A photomask film on which a black circle having a diameter of 85 μm is printed is adhered to both surfaces of the substrate on which the layer of the adhesive for electroless plating is formed in the above (7), and is 500 mJ / cm 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,
A heat treatment at 100 ° C. for 1 hour, 120 ° C. for 1 hour, and 150 ° C. for 3 hours is performed.
(See FIG. 3 (c)). Note that the tin plating layer was partially exposed in the opening serving as the via hole.

(9) The substrate having the via hole opening 6 formed thereon was 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. Was roughened to obtain a roughened surface. Then, it was immersed in a neutralizing solution (manufactured by Shipley) and washed with water (see FIG. 3D). 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.

(10) Next, the substrate was immersed in an electroless copper plating aqueous solution having the following composition, and the thickness was 0.6 to 1.
An electroless copper plating film 12 of 2 μm was formed (FIG. 4A)
reference). [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] 20 minutes at a liquid temperature of 65 ° C

(11) A commercially available photosensitive dry film was stuck on the electroless copper plating film 12, and a mask was placed on the film.
Exposure at mJ / cm ² and development treatment with a 0.8% aqueous solution of sodium carbonate provided a plating resist 3 having a thickness of 15 μm (see FIG. 4B).

(12) Then, electroplating was performed on the non-resist-formed portion under the following conditions to form an electroplated film 1 having a thickness of 15 μm.
No. 3 was formed (see FIG. 4C). [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 ℃

(13) Further, after the plating resist is peeled 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 to form an independent upper layer. The conductor circuit 5 (including the via hole 7) was used (see FIG. 4D).

(14) 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 11 made of Cu—Ni—P was formed (see FIG. 5A). (15) By repeating the above steps (6) to (14), a conductor circuit of an upper layer is further formed, and thereafter, a solder resist layer and a solder bump are formed to obtain a multilayer printed wiring board (FIG. 5 (b) to FIG. 6 (c)).

(Example 2) In the step of (5), 10 parts by weight of an imidazole copper (II) complex was used as an etching solution.
Using a mixture of 7 parts by weight of glycolic acid, 5 parts by weight of potassium chloride, and 78 parts by weight of ion-exchanged water, the conductor circuit is etched to form a roughened surface having a height (Rj) of 1.5 μm. A printed wiring board was obtained in the same manner as in Example 1 except for the formation.

(Example 3) A printed wiring board was obtained in the same manner as in Example 1 except that in step (6), a coating layer was formed using a zinc plating solution instead of a tin displacement plating solution. Was. At this time, zinc chloride (2 mol / l), thiourea (0.5 mol / l), sodium hypophosphite (0.5 mol / l), gelatin (1200 mg / l)
l) The substrate after the roughening treatment was immersed in a zinc plating solution at 45 ° C. containing a surfactant (PEG) (1200 mg / l) for 12 minutes to form 0.25 μm on the roughened layer.
m of a zinc coating layer was formed.

(Example 4) In the step of forming the coating layer in Example 1 (ie, the step (6)), tin borofluoride (0.5 mol / l) and thiourea (0.375 mol / l) were used.
/ L), sodium hypophosphite (20 g /
l), polyethylene glycol (10
Example 1 except that a Cu-Sn substitution reaction was carried out for 60 seconds using a tin-substitution plating solution at a temperature of 25 ° C. containing 200 mg / l) and a 0.04 μm-thick Sn layer was provided on the surface of the roughened layer.
A printed wiring board was obtained in the same manner as described above.

Example 5 In the step of forming the coating layer of Example 2, tin borofluoride (0.5 mol / l)
A tin displacement plating solution containing thiourea (0.375 mol / l), sodium hypophosphite (20 g / l) as a reducing agent, and polyethylene glycol (1000 mg / l) as a surfactant at a temperature of 25 ° C. is used for 60 seconds. Cu-Sn
After the substitution reaction, the surface of the roughened layer was coated with Sn having a thickness of 0.03 μm.
A printed wiring board was obtained in the same manner as in Example 2 except that a layer was provided.

(Embodiment 6) In the step of forming a roughened surface on the conductor circuit of Embodiment 1 (ie, the step (5)), a mixed aqueous solution containing sulfuric acid and hydrogen peroxide solution was used as an etching solution. By etching the conductor circuit
In the step of forming a roughened surface having a height of irregularities (Rj) of 3 μm and forming a coating layer (ie, step (6)), tin borofluoride (0.5 mol / l) and thiourea ( 0.375 mol / l), sodium hypophosphite (20 g / l) as a reducing agent, and polyethylene glycol (1000 mg / l) as a surfactant.
A Cu-Sn substitution reaction was carried out for 60 seconds using a tin-substituted plating solution of No. 1, and a printed wiring board was obtained in the same manner as in Example 1 except that a Sn layer having a thickness of 0.04 μm was provided on the surface of the roughened layer. .

(Embodiment 7) A. Preparation of Resin Film for Interlayer Resin Insulation Layer Bisphenol A type epoxy resin (Epoxy equivalent 46
9. Yuka Shell Epoxy Epicoat 1001) 3
0 parts by weight, 40 parts by weight of a cresol novolak type epoxy resin (epoxy equivalent: 215, Epichron N-673 manufactured by Dainippon Ink and Chemicals, Inc.), a triazine structure-containing phenol novolak resin (phenolic hydroxyl group equivalent: 120,
FENOLITE KA-705 manufactured by Dainippon Ink and Chemicals, Inc.
2) 30 parts by weight were dissolved by heating in 20 parts by weight of ethyl diglycol acetate and 20 parts by weight of solvent naphtha while stirring, and epoxidized polybutadiene rubber (Denalex R-45EPT manufactured by Nagase Kasei Kogyo Co., Ltd.) was added thereto.
15 parts by weight, 1.5 parts by weight of a crushed product of 2-phenyl-4,5-bis (hydroxymethyl) imidazole, 2 parts by weight of finely divided silica, and 0.5 part by weight of a silicon-based antifoaming agent are added to the epoxy resin composition. Was prepared. The resulting epoxy resin composition is applied on a 38 μm-thick PET film using a roll coater so that the thickness after drying becomes 50 μm, and then dried at 80 to 120 ° C. for 10 minutes to form an interlayer resin. A resin film for an insulating layer was produced.

B. Preparation of resin filler A resin filler was prepared in the same manner as in Example 1.

C. Manufacturing method of printed wiring board (1) Glass epoxy resin or BT with a thickness of 0.8 mm
A starting material was a copper-clad laminate in which 18 μm copper foils 8 were laminated on both sides of a substrate 1 made of (bismaleimide triazine) resin (see FIG. 7A). First, the copper-clad laminate was drilled, subjected to an electroless plating treatment, and etched in a pattern to form a lower conductor circuit 4 and a through hole 9 on both surfaces of the substrate 1.

(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. 7B). .

(3) After preparing the resin filler described in the above B, within 24 hours after preparation by the following method, the conductive circuit non-formed portion and the conductive circuit in the through hole 9 and on one side of the substrate 1 A layer of the resin filler 10 was formed on the outer edge portion of No. 4. That is, first, the resin filler was pushed into the through holes using a squeegee, and then dried at 100 ° C. for 20 minutes. Next, a mask having an opening corresponding to the conductive circuit non-forming portion is placed on the substrate, and a layer of the resin filler 10 is formed in the conductive circuit non-forming portion having a concave portion using a squeegee. Drying was performed at 20 ° C. for 20 minutes (see FIG. 7C).

(4) One surface of the substrate after the treatment of the above (3) is subjected to belt sander polishing using # 600 belt abrasive paper (manufactured by Sankyo Rikagaku) to form the surface of the inner layer copper pattern 4 and the through holes 9. Polishing was performed so that the resin filler 10 did not remain on the land surface, and then buffing was performed to remove scratches caused by the belt sander polishing. Such a series of polishing was similarly performed on the other surface of the substrate. Next, a heat treatment was performed at 100 ° C. for 1 hour and at 150 ° C. for 1 hour to cure the resin filler 10.

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 surface 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. 7D). That is, by this step, the surface of the resin filler 10 and the surface of the lower conductive circuit 4 become flush with each other.

(5) Next, both surfaces of the substrate 1 on which the lower conductor circuit 4 is formed are alkali-degreased and soft-etched, and then imidazole copper (II) complex 1 is used as an etching solution.
Using a mixture of 0 parts by weight, 7 parts by weight of glycolic acid, 5 parts by weight of potassium chloride and 78 parts by weight of ion-exchanged water, the conductor circuit is etched to roughen the unevenness height (Rj) to 3 μm. A surface was formed (see FIG. 8A).

(6) Then, tin borofluoride (0.5 mol
l / l), thiourea (0.375 mol / l), sodium hypophosphite (20 g / l) as a reducing agent, polyethylene glycol (1000 mg / l) as a surfactant
And a Cu-Sn substitution reaction for 60 seconds using a tin-substitution plating solution having a temperature of 25 ° C. and a thickness of 0.03 mm on the surface of the roughened layer.
A μm Sn layer was provided. In addition, about this Sn layer,
Not shown.

(7) Next, on both surfaces of the substrate, the interlayer resin insulating layer was formed by attaching the resin film for the interlayer resin insulating layer prepared in the above A by using a vacuum laminator apparatus by the following method ( FIG. 8B). That is, the resin film for the interlayer resin insulation layer is placed on the substrate,
Vacuum degree 0.5 Torr, pressure 4 kgf / cm ² , temperature 8
Paste under the condition of 0 ° C. and crimping time of 60 seconds.
Heat cured at 0 ° C. for 30 minutes.

(8) Next, a CO ₂ gas laser having a wavelength of 10.4 μm is used to form a beam diameter of 4.0 through a mask having a through hole having a thickness of 1.2 mm formed on the interlayer resin insulating layer 2.
8 mm, a top hat mode, a pulse width of 8.0 μsec, a diameter of a through hole of the mask of 1.0 mm, and a one-shot condition, a via hole opening 6 of 80 μm in diameter was formed in the interlayer resin insulating layer 2 (FIG. c)).

(9) The substrate in which the via hole opening 6 was formed was placed in a 80 ° C. solution containing 60 g / l of permanganate.
The surface of the interlayer resin insulating layer 2 including the inner wall of the via hole opening 6 was roughened by dissolving and removing the epoxy resin particles present on the surface of the interlayer resin insulating layer 2 by immersing for 0 minutes (FIG. 8 ( d)).

(10) Next, the substrate after the above treatment was immersed in a neutralizing 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 resin insulating layer 2 and the inner wall surface of the via hole opening 6.

(11) Next, the substrate is immersed in an electroless copper plating aqueous solution having the following composition, and has a thickness of 0.6 to 3.
An electroless copper plating layer 12 of 0 μm was formed (FIG. 9A)
reference). [Electroless plating aqueous solution] NiSO ₄ 0.003 mol / l tartaric acid 0.200 mol / l copper sulfate 0.030 mol / l HCHO 0.050 mol / l NaOH 0.100 mol / l α, α'-bipyridyl 40 mg / l Polyethylene glycol (PEG) 0.10 g / l [Electroless plating conditions] 40 minutes at a liquid temperature of 35 ° C

(12) A commercially available photosensitive dry film was stuck on the electroless copper plating layer 12, a mask was placed thereon, and
Exposure was performed at mJ / cm ² , and a development treatment was performed with a 0.8% aqueous sodium carbonate solution to provide a plating resist 3 having a thickness of 30 μm (see FIG. 9B).

(13) Subsequently, the substrate was washed with water at 50 ° C., degreased, washed with water at 25 ° C., further washed with sulfuric acid, and then subjected to electrolytic copper plating under the following conditions. The layer 13 was formed (see FIG. 9C). [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 ℃

(14) Further, the plating resist 3 was changed to 5% Na
After stripping off with an OH aqueous solution, the electroless plating film 12 under the plating resist 3 is dissolved and removed by etching with a mixed solution of sulfuric acid and hydrogen peroxide, and is composed of an electroless copper plating film 12 and an electrolytic plating film 13. An independent upper-layer conductor circuit 5 (including via holes 7) having a thickness of 20 μm was formed (FIG. 9D).
reference).

(15) By repeating the above steps (5) to (14), a further upper layer conductive circuit was formed, and a multilayer wiring board was obtained (see FIGS. 10 (a) to 11 (b)). .

(16) Next, a cresol novolak type epoxy resin (manufactured by Nippon Kayaku Co., Ltd.) dissolved in diethylene glycol dimethyl ether (DMDG) so as to have a concentration of 60% by weight was used. 46.67 parts by weight of an oligomer for imparting properties (molecular weight: 4000), 15.0 parts by weight of a bisphenol A type epoxy resin (trade name: Epicoat 1001 manufactured by Yuka Shell Co., Ltd.) dissolved in methyl ethyl ketone, and imidazole cured Agent (Shikoku Chemicals, trade name: 2E4MZ-CN)
1.6 parts by weight, 3.0 parts by weight of a polyvalent acrylic monomer (trade name: R604, manufactured by Nippon Kayaku Co., Ltd.), which is a photosensitive monomer, and similarly polyvalent acrylic monomer (trade name: DPE6A, manufactured by Kyoei Chemical Co., Ltd.) 1 0.5 part by weight and 0.71 part by weight of a dispersion defoaming agent (manufactured by San Nopco Co., Ltd., S-65) are placed in a container, stirred and mixed to prepare a mixed composition, and photopolymerization of the mixed composition is started. 2.0 parts by weight of benzophenone (manufactured by Kanto Kagaku) and 0.2 parts by weight of Michler's ketone (manufactured by Kanto Kagaku) as a photosensitizer were added, and the viscosity was 1.4 ± 0.3 Pa · s at 25 ° C. A solder resist composition adjusted to the above was obtained. The viscosity was measured using a B-type viscometer (DVL-B type, manufactured by Tokyo Keiki Co., Ltd.) at 60 rpm with rotor N.
o. In the case of 4, 6 rpm, the rotor No. According to 3.

(17) Next, the above-mentioned solder resist composition is applied to both surfaces of the multilayer wiring board in a thickness of 20 μm,
After drying at 20 ° C. for 20 minutes and at 70 ° C. for 30 minutes, the solder pad pattern is drawn to a thickness of 5 mm.
The photomask of 10
It was exposed to ultraviolet light of 00 mJ / cm ² and developed with a DMTG solution to form an opening having a diameter of 200 μm. And
Further, at 80 ° C. for 1 hour, at 100 ° C. for 1 hour, at 120 ° C.
For 1 hour and at 150 ° C. for 3 hours to cure the solder resist layer by heating, and have an opening,
A solder resist layer 14 having a thickness of 20 μm was formed. In addition, a commercially available solder resist composition can also be used as the solder resist composition.

(18) Next, sodium persulfate is used as a main component.
Etching solution with an etching ability of about 2 μm per minute
In the etching solution.
The substrate on which the dist layer 14 is formed is immersed for one minute,
Roughened surface with average roughness (Ra) of 1 μm or less is formed on the road surface
did. Further, this substrate was coated with nickel chloride (2.3 × 1).
0^-1mol / l), sodium hypophosphite (2.8 × 1
0^-1mol / l), sodium citrate (1.6 × 10
^-1mol / l) electroless nickel with pH = 4.5
Immerse in a plating solution for 20 minutes, and place a 5 μm
A Kel plating layer 15 was formed. In addition, shear the substrate
Potassium gold (7.6 × 10^-3mol / l), chloride
Nmonium (1.9 × 10^-1mol / l), sodium citrate
Thorium (1.2 × 10^-1mol / l), sodium hypophosphite
Thorium (1.7 × 10^-1mol / l)
Immerse in plating solution at 80 ° C for 7.5 minutes,
Gold plating layer 1 having a thickness of 0.03 μm
6 was formed as a solder pad.

(19) Thereafter, a solder paste was printed in the openings of the solder resist layer 14 and reflowed at 200 ° C. to form the solder bumps 17, thereby manufacturing a multilayer printed wiring board having the solder bumps 17 ( FIG. 11C).

(Embodiment 8) In the step of forming a roughened surface on the conductor circuit of Embodiment 7 (ie, the step (5)), a mixed solution containing sulfuric acid and hydrogen peroxide solution was used as an etching solution. The printed circuit board was obtained in the same manner as in Example 7 except that a roughened surface having a height (Rj) of 2.5 μm was formed by etching the conductive circuit.

Example 9 (1) Glass epoxy resin or BT having a thickness of 0.8 mm
A starting material was a copper-clad laminate in which 18 μm copper foils 8 were laminated on both sides of a substrate 1 made of (bismaleimide-triazine) resin (see FIG. 12A). First, the copper-clad laminate is drilled, and then a plating resist is formed. Then, the substrate is subjected to an electroless copper plating process to form through holes 9, and the copper foil is patterned in a conventional manner. Then, an inner copper pattern (lower conductive circuit) 4 was formed on both surfaces of the substrate.

(2) The substrate on which the lower conductor circuit 4 is formed is washed with water and dried, and then an etching solution is sprayed on both surfaces of the substrate by spraying, so that the surface of the lower conductor circuit 4, the land surface of the through hole 9, and the inner wall are formed. And by etching
Roughened surfaces 4a and 9a were formed on the entire surface of the lower conductor circuit 4 (see FIG. 12B). As an etching solution, 10 parts by weight of an imidazole copper (II) complex, 7 parts by weight of glycolic acid,
A mixture of 5 parts by weight of potassium chloride and 78 parts by weight of ion-exchanged water was used.

(3) The resin filler 10 containing a cycloolefin resin as a main component is mixed with the through hole 9 by the following method.
A layer of the resin filler 10 was formed inside and on the one-side surface of the substrate 1 where no conductive circuit was formed and on the outer edge of the conductive circuit 4. That is, first, the resin filler was pushed into the through holes using a squeegee, and then heated and dried. Next, a mask having an opening corresponding to the conductive circuit non-forming portion is placed on the substrate, and a layer of the resin filler 10 is formed in the conductive circuit non-forming portion having a concave portion using a squeegee. It was dried (see FIG. 12 (c)).

(4) One surface of the substrate after the treatment of the above (3) is subjected to belt sanding using a belt polishing paper (manufactured by Sankyo Rikagaku Co., Ltd.) to form a surface of the lower conductive circuit 4 and a land surface of the through hole 9. Was polished so that the resin filler 10 did not remain, and then buffed 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. Then, the filled resin filler 10 was cured by heating (see FIG. 12D).

In this way, the surface layer of the resin filler 10 filled in the through holes 9 and the like and the roughened layer 4a on the upper surface of the lower conductor circuit 4 are removed to flatten both surfaces of the substrate, and the resin filler 10 and the lower layer are removed. A wiring board was obtained in which the side surfaces of the conductive circuit 4 were firmly adhered through the roughened surface 4a, and the inner wall surface of the through hole 9 was tightly adhered to the resin filler 10 through the roughened surface 9a.

(5) Next, after the both surfaces of the substrate 1 on which the lower conductor circuit 4 is formed are alkali-degreased and soft-etched, the same etching solution as the etching solution used in the above (2) is sprayed, and sprayed. By etching the surface of the lower conductive circuit 4 once flattened and the land surface of the through hole 9, the roughened surface 4 is formed on the entire surface of the lower conductive circuit 4.
a and 9a were formed (see FIG. 13A).

(6) Then, tin borofluoride (0.5 mol
l / l), thiourea (0.375 mol / l), sodium hypophosphite (20 g / l) as a reducing agent, polyethylene glycol (1000 mg / l) as a surfactant
And a Cu-Sn substitution reaction for 60 seconds using a tin-substitution plating solution at a temperature of 25 ° C. and a thickness of 0.02 mm on the surface of the roughened layer.
A μm Sn layer was provided. In addition, about this Sn layer,
Not shown.

(7) Next, on both surfaces of the substrate having undergone the above steps,
A pressure of 5 kg / c while heating a thermosetting type cycloolefin resin sheet having a thickness of 50 μm to a temperature of 50 to 150 ° C.
Vacuum compression lamination was performed at m ² to provide an interlayer resin insulating layer 2 made of a cycloolefin-based resin (see FIG. 13B). The degree of vacuum during vacuum compression was 10 mmHg.

(8) Next, a CO ₂ gas laser having a wavelength of 10.4 μm was used to obtain a cycloolefin resin under the conditions of a beam diameter of 5 mm, a top hat mode, a pulse width of 50 μsec, a mask hole diameter of 0.5 mm, and three shots. A via hole opening 6 having a diameter of 80 μm was provided in the interlayer resin insulating layer 2 made of (see FIG. 13C). Thereafter, a desmear treatment was performed using oxygen plasma.

(9) Next, SV manufactured by Japan Vacuum Engineering Co., Ltd.
The surface of the interlayer resin insulating layer 2 was roughened by performing a plasma treatment using −4540 (see FIG. 13D). On this occasion,
Argon gas is used as the inert gas, and power 200
Plasma treatment was performed for 2 minutes under the conditions of W, gas pressure 0.6 Pa, and temperature 70 ° C.

(10) Next, using the same apparatus, after replacing the internal argon gas, sputtering using a Ni—Cu alloy as a target was performed at a pressure of 0.6 Pa, a temperature of 80 ° C., a power of 200 W, and a time of 5 minutes. Under the conditions, the Ni—Cu alloy layer 12 was formed on the surface of the polyolefin-based interlayer resin insulating layer 2. At this time, the thickness of the formed Ni—Cu alloy layer 12 was 0.2 μm (see FIG. 14A).

(11) A commercially available photosensitive dry film was stuck on both surfaces of the substrate after the above treatment, a photomask film was placed thereon, and after exposure at 100 mJ / cm ² ,
Development was performed with 0.8% sodium carbonate to form a pattern of the plating resist 3 having a thickness of 20 μm (FIG. 14B).
reference).

(12) Next, electrolytic copper plating was performed under the following conditions to form an electrolytic copper plating film 13 having a thickness of 15 μm (see FIG. 14C). The electrolytic copper plating film 13
As a result, in the steps described later, the portion to be the conductor circuit 5 is thickened, and the portion to be the via hole 7 is filled with plating. The additive in the electroplating aqueous solution is Capparaside HL manufactured by Atotech Japan.

[Electroplating aqueous solution] sulfuric acid 2.24 mol / l copper sulfate 0.26 mol / l additive 19.5 ml / l [electroplating conditions] current density 1 A / dm ² hours 65 minutes temperature 22 ± 2 ° C

(13) Next, the plating resist 3 is made of 5% Na
After stripping and removing with OH, the Ni-Cu alloy layer 12 existing under the plating resist 3 is dissolved and removed by an etching process using a mixed solution of nitric acid, sulfuric acid and hydrogen peroxide to form an electrolytic copper plating film. A conductor circuit 5 (including a via hole 7) having a thickness of 16 μm and comprising 13 or the like was formed (FIG. 14).
(D)).

(14) Subsequently, the above steps (5) to (13) were repeated to form a further upper layer conductive circuit.
(See FIG. 15A to FIG. 16B).

(15) Next, the viscosity was adjusted to 2 in the same manner as in Example 7.
A solder resist composition adjusted to 1.4 ± 0.3 Pa · s at 5 ° C. was obtained, and a solder resist layer 14 having an opening and a thickness of 20 μm was obtained in the same manner as in Example 7.
Was formed.

(16) Next, the substrate on which the solder resist layer 14 was formed was coated with nickel chloride (2.3 × 10 ^-1 mol / mol).
l), sodium hypophosphite (2.8 × 10 ⁻¹ mol /
l), sodium citrate (1.6 × 10 ⁻¹ mol /
2) in the electroless nickel plating solution having pH = 4.5 containing l)
This was immersed for 0 minutes to form a nickel plating layer 15 having a thickness of 5 μm in the opening. Furthermore, the substrate gold potassium cyanide ^{(7.6 × 10 -3 mol / l} ), ammonium chloride ^{(1.9 × 10 -1 mol / l} ), sodium citrate (1.2 × 10 ^-1 mol / l), immersed in an electroless plating solution containing sodium hypophosphite (1.7 × 10 ^-1 mol / l) at 80 ° C. for 7.5 seconds to form a layer having a thickness of 0 A 0.03 μm gold plating layer 16 was formed to form a solder pad.

(17) Thereafter, a solder paste is printed on the openings of the solder resist layer 14 and reflowed at 200 ° C. to form the solder bumps 17, thereby manufacturing a multilayer printed wiring board having the solder bumps 17 ( FIG. 16 (c)).

(Embodiment 10) In the step of forming a roughened surface on the conductor circuit of Embodiment 9 (ie, the step of (5))
Except that a roughened surface having a height (Rj) of 2.5 μm was formed by etching a conductor circuit using a mixed solution containing sulfuric acid and a hydrogen peroxide solution as an etchant. In the same manner as in No. 9, a printed wiring board was obtained.

(Comparative Example 1) In the step of forming the coating layer in Example 1 (ie, the step (6)), a plating solution containing neither gelatin nor a surfactant was used as the tin-substituted plating solution. A printed wiring board was obtained in the same manner as in Example 1 except that was formed.

(Comparative Example 2) In the step of forming a coating layer of Example 5, plating at a temperature of 35 ° C containing tin borofluoride (1 mol / l) and thiourea (1 mol / l) as a tin displacement plating solution. Using liquid, Cu-Sn for 450 seconds
Except for forming a coating layer by performing a substitution reaction,
A printed wiring board was obtained in the same manner as in Example 5.

(Comparative Example 3) In the step of forming the coating layer in Example 7 (that is, the step (6)), tin borofluoride (1 mol / l) and thiourea (1 mol / l) were used as the tin displacement plating solutions. ) By performing a Cu-Sn substitution reaction for 450 seconds using a plating solution having a temperature of 35 ° C.
A printed wiring board was obtained in the same manner as in Example 7 except that the coating layer was formed.

(Comparative Example 4) In the step of forming the coating layer of Example 9 (ie, the step (6)), tin borofluoride (1 mol / l) and thiourea (1 mol / l) were used as the tin displacement plating solutions. ) By performing a Cu-Sn substitution reaction for 450 seconds using a plating solution having a temperature of 35 ° C.
Except having formed the coating layer, it carried out similarly to Example 9, and obtained the printed wiring board.

Examples 1 to 10 and Comparative Examples 1 to 4
The average roughness (Ra) of the roughened layer before and after the formation of the coating layer, the state of the coating layer, discoloration of the lower conductive circuit after the roughening, the presence or absence of dissolution, Comparative evaluation was performed on a total of five items including the presence or absence of halos (peeling), the peeling of the interlayer resin insulating layer after the reliability test, the disconnection of the conductor circuit, and the results of the continuity test. The results are shown in Table 1 below.

[0180]Evaluation method  (1) Surface roughness Surface roughness profile measuring machine manufactured by Tokyo Seimitsu Co., Ltd.
A / 480A.

(2) State of coating layer The state of the wiring after plating was observed with a microscope, and the following discoloration, abnormal deposition, and the presence or absence of whiskers were evaluated according to the following criteria. (a) Discoloration: Some were blackened or oxidized, and others were not. (b) Abnormal deposition: Some were deposited between wirings, others were not. (c) Whisker: Some have whiskers,
Others were ignored.

(3) State of Lower Layer Conductor Circuit after Roughening After roughening the interlayer resin insulating layer with a chromic acid solution, the via holes exposed from the openings are observed with a microscope, and discoloration and dissolution of the via holes occur. Was determined according to the following evaluation criteria. (a) Discoloration: Some parts differed in color from other parts, such as blackening and whitening, and others were not. (b) Dissolution: The cross section of the via hole was cut to confirm the presence or absence of dissolution.

(4) Presence or Absence of Peeling of Interlayer Resin Insulating Layer After the formation of the solder bumps, the printed wiring board was cut to form a cross section, and the presence or absence of peeling of the interlayer resin insulating layer was determined by observing with a microscope. .

(5) Disconnection after Reliability Test After a reliability test in which a voltage of 1.2 V is applied for 200 hours under a condition of temperature: 85 ° C. and relative humidity: 85%, current is applied.
The printed wiring board was cut to form a cross section, and the presence or absence of disconnection of the wiring and peeling of the interlayer resin insulating layer was determined by observation with a microscope. In addition, a continuity test was performed, and the continuity state was determined from the results displayed on the monitor.も の indicates that there was continuity, and X indicates that there was no continuity.

[0185]

[Table 1]

As is clear from the results shown in Table 1 above, in Examples 1 to 10, all the evaluation items were good, while in Comparative Examples 1 to 4, discoloration of the coating layer and whisker In some cases, peeling of the insulating layer and disconnection of the conductor circuit have occurred.

[0187]

As described above, according to the electroless plating solution of the present invention, when a conductor circuit having a roughened surface is coated, abnormal conductors between the conductor circuits and whiskers are generated due to abnormal deposition between the conductor circuits. An interlayer resin capable of forming a covering layer so as to substantially maintain the shape of the roughened surface without short-circuiting the circuits, and having excellent adhesion to the conductor circuit on the conductor circuit on which the covering layer is formed. An insulating layer can be formed.
Further, according to the method for manufacturing a printed wiring board of the present invention, since the coating layer is formed on the conductor circuit using the electroless plating solution, the adhesiveness with the interlayer insulating layer formed thereon is excellent. Printed wiring boards can be manufactured.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing a lower conductor circuit after a coating layer is formed on the lower conductor circuit using the electroless plating solution of the present invention.

FIGS. 2A to 2D are cross-sectional views showing a part of the manufacturing process of the printed wiring board of the present invention.

FIGS. 3A to 3D are cross-sectional views showing a part of the manufacturing process of the printed wiring board of the present invention.

FIGS. 4A to 4D are cross-sectional views showing a part of the manufacturing process of the printed wiring board of the present invention.

FIGS. 5A to 5C are cross-sectional views showing a part of the manufacturing process of the printed wiring board of the present invention.

FIGS. 6A to 6C are cross-sectional views showing a part of the manufacturing process of the printed wiring board of the present invention.

FIGS. 7A to 7D are cross-sectional views showing a part of the manufacturing process of the printed wiring board of the present invention.

FIGS. 8A to 8D are cross-sectional views illustrating a part of the manufacturing process of the printed wiring board of the present invention.

FIGS. 9A to 9D are cross-sectional views illustrating a part of the manufacturing process of the printed wiring board of the present invention.

FIGS. 10A to 10C are cross-sectional views illustrating a part of the manufacturing process of the printed wiring board of the present invention.

FIGS. 11A to 11C are cross-sectional views illustrating a part of the manufacturing process of the printed wiring board of the present invention.

FIGS. 12A to 12D are cross-sectional views illustrating a part of the manufacturing process of the printed wiring board of the present invention.

FIGS. 13A to 13D are cross-sectional views illustrating a part of the manufacturing process of the printed wiring board of the present invention.

FIGS. 14A to 14D are cross-sectional views illustrating a part of the manufacturing process of the printed wiring board of the present invention.

FIGS. 15A to 15C are cross-sectional views illustrating a part of the manufacturing process of the printed wiring board of the present invention.

16 (a) to (c) are cross-sectional views showing a part of the manufacturing process of the printed wiring board of the present invention.

FIG. 17 is a cross-sectional view schematically illustrating a case where a roughening layer formed on a conductor circuit is covered by a coating layer when the roughening layer is coated.

FIGS. 18 (a) and (b) are cross-sectional views schematically showing a case where a bridge-like coating layer is formed when coating a roughened layer formed on a conductor circuit.

FIG. 19 is a perspective view schematically showing an example in which abnormal deposition occurs between the conductor circuits when covering the roughened layer formed on the conductor circuits.

FIG. 20 is a perspective view schematically showing an example in which whiskers are generated in a coating layer when coating a roughened layer formed on a conductor circuit.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Substrate 2 (2a, 2b) Interlayer resin insulation layer (adhesive layer for electroless plating) 4 Lower-layer conductor circuit 4a Roughened surface 4b Coating layer 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 plated film 16 Gold plated film 17 Solder bump

Claims (7)

[Claims] (1) A conductor circuit is formed on an insulating substrate,
After forming a roughened surface by subjecting the conductor circuit to a roughening process, or (2) a conductor formed in a plurality of layers of conductor circuits on an insulating substrate with an interlayer insulating layer interposed therebetween, and formed on the uppermost layer An electroless plating solution used for forming a coating layer on the roughened surface formed in (1) or (2) after forming a roughened surface by performing a roughening forming process on the circuit, at least An electroless plating solution comprising a metal salt, a complexing agent, a reducing agent, and a surfactant. 2. The electroless plating solution according to claim 1, wherein the metal salt is at least one selected from the group consisting of tin salts, zinc salts, nickel salts, cobalt salts, thallium salts, and lead salts. 3. The electroless plating solution according to claim 1, wherein the surfactant is at least one selected from the group consisting of polyethylene glycol, polypropylene oxide, and polyethylene oxide. 4. The concentration of the metal salt is 0.01 to 3 mol.
/ L, and the concentration of the complexing agent is 0.1 to 2 mol / l.
The electroless plating solution according to any one of claims 1 to 3, wherein the concentration of the reducing agent is 1 to 80 g / l, and the concentration of the surfactant is 0.1 to 10 g / l. 5. The electroless plating solution according to claim 1, further comprising gelatin. 6. The concentration of the gelatin is from 100 to 200.
The electroless plating solution according to claim 5, wherein the amount is 0 mg / l. 7. A method for manufacturing a printed wiring board, wherein a conductor circuit comprising a plurality of layers with an interlayer insulating layer interposed therebetween is formed on an insulating substrate, wherein the conductor circuit is subjected to a roughening process to reduce a roughened surface. After forming and forming a coating layer on the roughened surface using the electroless plating solution according to any one of claims 1 to 6, the substrate surface including the conductor circuit on which the coating layer is formed is subjected to interlayer insulation. A method for manufacturing a printed wiring board, comprising coating with a material.