JP2002151841A - Method of manufacturing multilayer printed wiring board - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method of manufacturing a multilayer printed wiring board, for which there is no risk of short-circuiting between adjoining conductor circuits, signal delay or signal error will not be generated, and superior connection reliability under thermal cycling and high-temperature/high-humidity conditions is realized by forming a plating resist, in which no gap is formed under its bottom part and which has a flat surface. SOLUTION: This method of manufacturing a multilayer printed wiring board contains the steps of (1) sticking a photosensitive dry film on an interlayer insulating resin layer on which a thin-film conductor layer has been formed; (2) forming a plating resist by applying exposure and development processes to the photosensitive dry film; and (3) forming conductor circuits in regions where the plating resin is not formed, wherein in the step (1), the photosensitive dry film is stuck after a roughened surface or a roughened layer has been formed on the surface of the thin-film conductor layer.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a method for manufacturing a multilayer printed wiring board.

[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 to form a conductor circuit, and a roughened surface is formed on the surface of the conductor circuit by electroless plating, etching, or the like. After forming an interlayer resin insulating layer, an exposure and development process is performed, or a via hole opening is formed by a laser process, and then the interlayer resin insulating layer is formed through UV curing and main curing.

Further, after a roughening process is performed on the interlayer resin insulating layer, a thin electroless plating film is formed on the roughened surface, and a plating resist is formed on the electroless plating film. Thickening is performed by plating, and etching is performed after the plating resist is stripped to form a conductive circuit connected to the lower conductive circuit by a via hole.

After repeating this, a solder resist layer for protecting the conductor circuit is formed as an outermost layer, an opening is formed in the solder resist layer, and the conductor layer in the opening is plated or the like to form a pad. Then, a build-up multilayer printed wiring board is manufactured by forming solder bumps.

In such a method for manufacturing a multilayer printed wiring board, a plating resist is prepared by attaching a photosensitive dry film to a thin conductor layer such as a thin electroless plating film, and exposing and developing the photosensitive dry film. It was formed by applying.

[0007]

As described above, when a photosensitive dry film is directly adhered onto an interlayer resin insulating layer having a thin film conductor layer on the surface, a part of the surface of the thin film conductor layer is oxidized. Since the physical properties of the surface of the thin-film conductor layer are not uniform, when the photosensitive dry film 18 is directly attached on the thin-film conductor layer 112 as shown in FIG. Photosensitive dry film 1
8 easily swelled (see FIG. 7A). Therefore, when the plating resist 103 is formed by performing the exposure and development processes, the surface of the plating resist 103 may become wavy due to the swelling, and a void may be formed at the bottom thereof (see FIG. 7 (b)), and thereafter, when the electroplating layer 113 is formed, the electroplating layer 113 is also formed in the void portion (see FIG. 7 (c)), and the plating resist 103 and the thin film conductor layer 112 are formed. In some cases, the conductor circuit 105 formed by the removal has a shape in which the bottom is widened (see FIG. 7D).

In the conductor circuit having such a shape, there is a problem that the interval between the bottoms of the adjacent conductor circuits is small, and a short circuit is easily generated between the adjacent conductor circuits. In particular, L
The problem described above was likely to occur between conductor circuits having a narrow width such as / S = 35/35. Note that the L / S refers to the width of the conductor wiring and the distance between the conductor wirings, and this is simply referred to as L / S in this specification. Further, in the conductor circuit having such a shape, it is difficult to match the impedance of the multilayer printed wiring board, and a signal delay or a signal error may occur.

The present invention has been made to solve such a problem, and an object of the present invention is to form a plating resist having a flat surface without forming a void at the bottom. Therefore, there is no possibility that a short circuit will occur between adjacent conductor circuits, no signal delay or signal error occurs, and a method of manufacturing a multilayer printed wiring board having excellent connection reliability under heat cycle conditions or high temperature and high humidity. To provide.

[0010]

Means for Solving the Problems The inventors of the present invention have conducted intensive studies for realizing the above object, and as a result, by forming a roughened surface or a roughened layer on the surface of a thin film conductor layer, a roughened surface or a roughened surface is formed. The physical properties of the surface of the thin film conductor layer including the layer become uniform,
When the photosensitive dry film is pressed onto the thin film conductor layer, the contact area between the two increases and the adhesion between the thin film conductor layer and the photosensitive dry film improves. The inventors have found that a resist can be formed, and have conceived of the present invention which has the following features as the main constitutions.

That is, in the method of manufacturing a multilayer printed wiring board according to the present invention, a step of attaching a photosensitive dry film on an interlayer resin insulating layer on which a thin film conductor layer is formed, and exposing and developing the photosensitive dry film are performed. A method of manufacturing a multilayer printed wiring board including a step of forming a plating resist by applying, and a step of forming a conductor circuit in a portion where no plating resist is formed, wherein the surface of the thin film conductor layer is roughened in the above step. After forming the surface or the roughened layer, a photosensitive dry film is attached.

In the method for manufacturing a multilayer printed wiring board, the roughened surface or the roughened layer has an average roughness Ra of 0.0
Desirably, it is 1 to 1 μm.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION A method for manufacturing a multilayer printed wiring board according to the present invention comprises the steps of: adhering a photosensitive dry film on an interlayer resin insulating layer having a thin film conductor layer formed thereon; exposing and developing the photosensitive dry film; A step of forming a plating resist by performing a process, and a method of manufacturing a multilayer printed wiring board including a step of forming a conductor circuit in a plating resist non-formed portion, wherein in the above-described step,
After forming a roughened surface or a roughened layer (hereinafter, also referred to simply as a roughened surface, etc. together) on the surface of the thin film conductor layer, a photosensitive dry film is attached.

According to the method for manufacturing a multilayer printed wiring board of the present invention, since the roughened surface or the like is formed on the surface of the thin film conductor layer, the physical properties of the surface of the thin film conductor layer become uniform, and When the photosensitive dry film was crimped, the contact area between the two was increased to improve the adhesion between the thin film conductor layer and the photosensitive dry film. Therefore, the photosensitive dry film was stuck on the thin film conductor layer. In this case, a swelling or the like does not occur in the photosensitive dry film, and a rectangular plating resist in close contact with the thin film conductor layer can be formed.

Therefore, after forming a plating resist,
When a conductor circuit is formed in a portion where the plating resist is not formed, a conductor circuit having a rectangular cross section can be formed, there is no risk of short circuit between adjacent conductor circuits, and no signal delay or signal error occurs. In addition, a multilayer printed wiring board having excellent connection reliability can be manufactured under heat cycle conditions or under high temperature and high humidity.

According to the manufacturing method of the present invention, in the step of attaching a photosensitive dry film on the interlayer resin insulating layer having the thin film conductor layer formed thereon, after forming a roughened surface or the like on the surface of the thin film conductor layer, Paste the dry film.

The method for forming the roughened surface includes, for example, an etching process, and the method for forming the roughened layer includes, for example, an oxidation-reduction process and an electroless plating process. Among these, an etching process is desirable. This is because when the roughened surface is formed by processing the surface of the thin film conductor layer, the conductor layer with excellent adhesion is directly formed on the surface of the thin film conductor layer by electroplating without passing through other layers. Because you can.

Examples of the etchant used for the above-mentioned etching treatment include a mixed aqueous solution of an organic acid and a cupric complex, and a mixed solution of aqueous hydrogen peroxide, sulfuric acid, and tetrazole. Examples of the oxidation-reduction treatment include an oxidation-reduction treatment using an aqueous solution containing NaOH, NaClO ₂ and Na ₃ PO ₄ as an oxidation bath, and an aqueous solution containing NaOH and NaBH ₄ as a reduction bath.
As the electroless plating process, for example, Cu-Ni-
P needle-like alloy plating treatment and the like.

The average roughness Ra of the roughened surface or the like is 0.01
It is desirably about 1 μm. When the average roughness Ra is less than 0.01 μm, the adhesion between the thin film conductor layer and the plating resist is not significantly improved, while the average roughness Ra is 1 μm.
When the thickness exceeds μm, the plating resist may remain on the surface of the thin film conductor layer including the roughened surface when the plating resist is peeled off, and then when the thin film conductor layer under the plating resist is removed by etching. Therefore, the thin film conductor layer cannot be reliably removed, which may cause a short circuit. More preferably,
It is 0.1 to 0.5 μm. Within this range, conflicting properties such as adhesion between the thin film conductor layer and the plating resist and ease of peeling of the plating resist can be achieved in a well-balanced manner.

FIGS. 1A to 1D are cross-sectional views showing a part of a manufacturing process of a multilayer printed wiring board using the manufacturing method of the present invention. In such a method for manufacturing a multilayer printed wiring board of the present invention, as shown in FIG. 1, a roughened surface 22 is formed on a thin film conductor layer 112, and a photosensitive dry film 18 is further adhered thereon. Therefore, the photosensitive dry film 18 does not swell (see FIG. 1A). Therefore, by performing the exposure and development processes, a void is not formed at the bottom, and the plating resist 103 having a rectangular cross section can be formed (see FIG. 1B).
Therefore, when the electroplating is performed thereafter, the electroplating layer 113 having excellent adhesion to the thin film conductor layer and having a rectangular cross section can be formed (see FIG. 1C). By removing the thin film conductor layer by etching treatment, there is no risk of short-circuiting between adjacent conductor circuits, and a conductor circuit 105 having excellent adhesion to an interlayer resin insulation layer or a solder resist layer is formed. (See FIG. 1D).

Next, a method of manufacturing such a multilayer printed wiring board of the present invention will be briefly described in the order of steps.

(1) First, a wiring board having a lower conductive circuit on the surface of a resin board is manufactured. As the resin substrate, a resin substrate having inorganic fibers is desirable, specifically, for example, a glass cloth epoxy substrate, a glass cloth polyimide substrate,
A glass cloth bismaleimide-triazine resin substrate, a glass cloth fluororesin substrate, and the like can be given. Further, a copper-clad laminate in which copper foil is stuck on both surfaces of the resin substrate may be used.

Usually, a through-hole is formed in the resin substrate by a drill, and the wall surface of the through-hole and the surface of the copper foil are subjected to electroless plating to form a through-hole. Copper plating is preferred as the electroless plating. Further, electroplating may be performed for thickening the copper foil. Copper plating is preferred as the electroplating. Thereafter, the inner wall of the through-hole may be subjected to a roughening treatment, the through-hole may be filled with a resin paste or the like, and the conductive layer covering the surface may be formed by electroless plating or electroplating.

Examples of the roughening method include blackening (oxidation) -reduction treatment, spray treatment with a mixed aqueous solution of an organic acid and a cupric complex, and treatment with a Cu-Ni-P needle-like alloy plating. No. Through the above steps, an etching resist is formed on the solid copper pattern formed on the entire surface of the substrate by using a photolithography technique, and then etching is performed to form a lower conductive circuit. Thereafter, if necessary, a resin or the like may be filled in the recessed portion formed by the formation of the conductor circuit.

(2) Next, the formed lower conductor circuit is subjected to a roughening treatment if necessary. As the method of the roughening treatment, the above-mentioned methods, that is, blackening (oxidation) -reduction treatment, spray treatment with a mixed aqueous solution of an organic acid and a cupric complex, Cu
-Ni-P needle-like alloy plating.
In addition, without subjecting the lower conductor circuit to a roughening treatment, the substrate on which the lower conductor circuit is formed is immersed in a solution in which a resin component is dissolved to form a resin layer on the surface of the lower conductor circuit. The adhesion to the interlayer resin insulating layer formed on the substrate may be ensured.

(3) Next, an interlayer resin insulating layer is formed on both surfaces of the wiring board having the lower conductive circuit manufactured in the above (2). As a material for 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 resin 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.

Specific examples of the material for forming these interlayer resin insulating layers include polyolefin-based resins, polyphenylene-based resins (PPE, PPO, etc.), and fluorine-based resins. As the polyolefin resin,
For example, the above-mentioned polyethylene, polypropylene, polyisobutylene, polybutadiene, polyisoprene, 2-norbornene, 5-ethylidene-2-norbornene, copolymers of these resins, and the like can be mentioned. Examples include tetrafluoroethylene copolymer resin (ETFE) and polychlorotrifluoroethylene (PCTFE).

Further, as a composite resin of a thermosetting resin and a thermoplastic resin, for example, a resin composition for forming a roughened surface can be used.

As the resin composition for forming a roughened surface, for example, an uncured heat-resistant resin matrix which is hardly soluble in a roughening liquid comprising at least one selected from an acid, an alkali and an oxidizing agent is used. Examples thereof include those in which a substance soluble in a roughening liquid comprising at least one selected from an acid, an alkali, and an oxidizing agent is dispersed. Note that the terms "sparingly soluble" and "soluble" are referred to as "soluble" for convenience when a substance having a relatively high dissolution rate is immersed in the same roughening solution for the same time, and the relative dissolution rate is relatively low. The slower one is called "poorly soluble" for convenience.

The heat-resistant resin matrix is preferably a matrix capable of maintaining the shape of the roughened surface when the roughened liquid is formed on the interlayer resin insulating layer using the roughening solution. , Thermoplastic resins, and composites thereof. Further, by using a photosensitive resin, an opening for a via hole may be formed in the interlayer resin insulating layer by using exposure and development processes.

Examples of the thermosetting resin include an epoxy resin, a phenol resin, a polyimide resin, a polyolefin resin, and a fluororesin. When the thermosetting resin is photosensitized, the thermosetting group is subjected to a (meth) acrylation reaction using methacrylic acid, acrylic acid, or the like. Particularly, a (meth) acrylate of an epoxy resin is desirable. Further, an epoxy resin having two or more epoxy groups in one molecule is more desirable. In addition to being able to form the above-described roughened surface, it is also excellent in heat resistance and the like, so that stress is not concentrated on the conductor circuit even under heat cycle conditions, and the conductor circuit and the interlayer resin insulation layer Peeling hardly occurs between the substrate and the substrate.

Examples of the thermoplastic resin include phenoxy resin, polyether sulfone, polysulfone, polyphenylene sulfone, polyphenylene sulfide, polyphenyl ether, polyether imide and the like. These may be used alone or in combination of two or more.

The substance soluble in the roughening liquid comprising at least one selected from the above-mentioned acids, alkalis and oxidizing agents is selected from inorganic particles, resin particles, metal particles, rubber particles, liquid resin and liquid rubber. It is desirable that it is at least one kind.

Examples of the inorganic particles include aluminum compounds, calcium compounds, potassium compounds, magnesium compounds, and silicon compounds. These may be used alone or in combination of two or more.

Examples of the aluminum compound include alumina and aluminum hydroxide. Examples of the calcium compound include calcium carbonate and
Calcium hydroxide and the like, as the potassium compound, for example, potassium carbonate and the like, as the magnesium compound, for example, magnesia, dolomite, basic magnesium carbonate, talc and the like,
Examples of the silicon compound include silica and zeolite. These may be used alone or 2
More than one species may be used in combination.

The alumina particles can be dissolved and removed with hydrofluoric acid, and calcium carbonate can be dissolved and removed with hydrochloric acid. Further, sodium-containing silica and dolomite can be dissolved and removed with an alkaline aqueous solution.

Examples of the resin particles include those made of a thermosetting resin, a thermoplastic resin and the like. When the resin particles are immersed in a roughening liquid comprising at least one selected from acids, alkalis and oxidizing agents, There is no particular limitation as long as the dissolution rate is faster than the heat-resistant resin matrix,
Specifically, for example, amino resin (melamine resin, urea resin, guanamine resin, etc.), epoxy resin, phenol resin, phenoxy resin, polyimide resin, polyphenylene resin, polyolefin resin, fluororesin, bismaleimide-triazine resin and the like can be mentioned. . These may be used alone or in combination of two or more.

The epoxy resin can be arbitrarily produced by dissolving it in an acid or an oxidizing agent or by hardly dissolving the same by selecting the type of oligomer and the curing agent. For example, a resin obtained by curing a bisphenol A-type epoxy resin with an amine-based curing agent is very soluble in chromic acid, but a resin obtained by curing a cresol novolac-type epoxy resin with an imidazole curing agent is not easily dissolved in chromic acid. .

It is necessary that the resin particles have been previously cured. If not cured, the resin particles will dissolve in the solvent that dissolves the resin matrix, so they will be uniformly mixed, and it will not be possible to selectively dissolve and remove only the resin particles with an acid or oxidizing agent. is there.

The metal particles include, for example, gold, silver,
Examples include copper, tin, zinc, stainless steel, aluminum, nickel, iron, lead, and the like. These may be used alone or in combination of two or more. The metal particles may have a surface layer coated with a resin or the like in order to ensure insulation.

Examples of the rubber particles include acrylonitrile-butadiene rubber, polychloroprene rubber, polyisoprene rubber, acrylic rubber, polysulfur-based rigid rubber, fluorine rubber, urethane rubber, silicone rubber, ABS resin and the like.

As the rubber particles, for example, polybutadiene rubber, various modified polybutadiene rubbers such as epoxy-modified, urethane-modified, (meth) acrylonitrile-modified, and (meth) acrylonitrile-butadiene rubber containing a carboxyl group are used. Can also. By using these rubber particles, the rubber particles are easily dissolved in an acid or an oxidizing agent. In other words, when dissolving the rubber particles using an acid, an acid other than a strong acid can be dissolved, and when dissolving the rubber particles using an oxidizing agent, permanganic acid having a relatively weak oxidizing power can be used. Can be dissolved. Even when chromic acid is used, it can be dissolved at a low concentration. Therefore, no acid or oxidizing agent remains on the surface of the interlayer resin insulating layer, and as described later,
When a catalyst such as palladium chloride is applied after formation of the roughened surface, no catalyst is applied or the catalyst is not oxidized. These may be used alone or in combination of two or more.

When two or more of the above soluble substances are used as a mixture, the combination of the two soluble substances to be mixed is preferably a combination of resin particles and inorganic particles. Both have low conductivity, so that the insulation of the interlayer resin insulation layer can be ensured, the thermal expansion can be easily adjusted with the poorly soluble resin, and the interlayer resin made of the resin composition for forming a roughened surface can be easily obtained. This is because no crack occurs in the insulating layer, and no peeling occurs between the interlayer resin insulating layer and the upper conductor circuit.

As the liquid phase resin, an uncured solution of the thermosetting resin can be used. Specific examples of such a liquid phase resin include, for example, an uncured epoxy oligomer and an amine-based curing agent. And the like. Examples of the liquid phase rubber include the above-mentioned polybutadiene rubber, various modified polybutadiene rubbers such as epoxy-modified, urethane-modified and (meth) acrylonitrile-modified, and uncured solutions such as (meth) acrylonitrile-butadiene rubber containing a carboxyl group. Can be used.

When the photosensitive resin composition is prepared using the liquid resin or the liquid rubber, the heat-resistant resin matrix and the soluble substance are not uniformly compatible with each other (that is, the phases are separated). As such, these materials need to be selected. By mixing a heat-resistant resin matrix and a soluble substance selected according to the above criteria, a state in which "islands" of liquid-phase resin or liquid-phase rubber are dispersed in the "sea" of the heat-resistant resin matrix Alternatively, a photosensitive resin composition in which "islands" of a heat-resistant resin matrix are dispersed in a "sea" of a liquid phase resin or a liquid phase rubber can be prepared.

After the photosensitive resin composition in such a state is cured, the roughened surface can be formed by removing the "sea" or "island" liquid phase resin or liquid phase rubber. .

Examples of the acid used as the roughening solution include phosphoric acid, hydrochloric acid, sulfuric acid, nitric acid, and organic acids such as formic acid and acetic acid. Among them, it is preferable to use an organic acid. This is because when the roughening treatment is performed, the metal conductor layer exposed from the via hole is hardly corroded. As the oxidizing agent, it is desirable to use, for example, an aqueous solution of chromic acid, chromic sulfuric acid, or an alkaline permanganate (such as potassium permanganate). As the alkali, an aqueous solution of sodium hydroxide, potassium hydroxide or the like is desirable.

The average particle size of the soluble substance is 10 μm
The following is desirable. Further, coarse particles having a relatively large average particle diameter of 2 μm or less and fine particles having a relatively small average particle diameter may be used in combination. That is, a soluble substance having an average particle size of 0.1 to 0.5 μm and an average particle size of 1
Combination with a soluble substance of ２2 μm, and the like.

As described above, the combination of coarse particles having a relatively large average particle size and fine particles having a relatively small average particle size eliminates the dissolution residue of the electroless plating film and reduces the amount of palladium catalyst under the plating resist. In addition, a shallow and complicated roughened surface can be formed. Further, by forming a complicated roughened surface, a practical peel strength can be maintained even if the unevenness of the roughened surface is small. The coarse particles have an average particle size of more than 0.8 μm and 2.0 μm.
m, the fine particles have an average particle size of 0.1 to 0.8 μm
It is desirable that

By combining the above coarse particles and fine particles, it is possible to form a shallow and complicated roughened surface. If the used particle size is coarse and the average particle size is less than 2 μm, these coarse particles can be formed. The anchor formed even when dissolved is removed becomes shallow, and the particles to be removed are formed by the mixture of coarse particles having a relatively large particle diameter and fine particles having a relatively small particle diameter. The roughened surface becomes complicated. By forming such a complicated roughened surface, a practical peel strength can be maintained even with a shallow roughened surface.

In this case, if the particle diameter used is coarse particles and the average particle diameter is less than 2 μm, the roughening proceeds too much and no voids are generated. Excellent in nature. In the resin composition for forming a roughened surface, the particle size of the soluble substance is the length of the longest portion of the soluble substance.

The coarse particles have an average particle diameter of more than 0.8 μm and less than 2.0 μm, and the fine particles have an average particle diameter of 0.1 to 0.1 μm.
When it is 0.8 μm, the depth of the roughened surface is approximately Rmax = 3
With the semi-additive method, not only the electroless plating film can be easily removed by etching, but also the palladium catalyst under the electroless plating film can be easily removed. 0 to 1.3 kg / c
m can be maintained.

The shape of the soluble substance is not particularly limited, and examples thereof include a spherical shape and a crushed shape. Further, the shape of the soluble substance is desirably a uniform shape. This is because a roughened surface having unevenness with a uniform roughness can be formed.

The above-mentioned resin composition for forming a roughened surface may contain an organic solvent so that it can be applied on a substrate or the like, or may be in the form of a film so that it can be pressed on a substrate or the like. (Hereinafter, also referred to as a resin film for forming a roughened surface). When the resin composition for forming a roughened surface contains an organic solvent, the content is 10%.
It is desirable that the content be not more than weight%.

In the above resin film for forming a roughened surface,
It is desirable that the soluble substance is substantially uniformly dispersed in the heat resistant resin matrix. A roughened surface having unevenness with a uniform roughness can be formed, and even if a via hole or a through hole is formed in a resin film, it is possible to secure adhesion to an upper layer conductive circuit formed thereon. Because. Further, the above-mentioned resin film for forming a roughened surface may be formed so as to contain a soluble substance only in a surface layer portion forming a roughened surface. Thereby, since the portions other than the surface layer portion of the roughened surface forming resin film are not exposed to the acid or the oxidizing agent, the insulation between the conductor circuits via the interlayer resin insulating layer is reliably maintained.

In the above resin film for forming a roughened surface,
The amount of the soluble substance dispersed in the hardly soluble resin is
The content is preferably 3 to 40% by weight based on the resin film for forming a roughened surface. If the amount of the soluble substance is less than 3% by weight,
In some cases, a roughened surface having desired irregularities cannot be formed. If the amount exceeds 40% by weight, when a soluble substance is dissolved using an acid or an oxidizing agent, the substance is dissolved to a deep portion of the resin film. In addition, the insulation between the conductor circuits via the interlayer resin insulation layer made of the resin film cannot be maintained, which may cause a short circuit.

The above-mentioned roughened surface forming resin film desirably contains a curing agent and other components in addition to the above-mentioned soluble substance and the above-mentioned heat-resistant resin matrix. Examples of the curing agent include imidazole-based curing agents, amine-based curing agents, guanidine-based curing agents, epoxy adducts of these curing agents and those obtained by microencapsulating these curing agents, triphenylphosphine, and tetraphenylphosphonate. Organic phosphine-based compounds such as ammonium tetraphenylborate.

The content of the curing agent is desirably 0.05 to 10% by weight based on the resin film for forming a roughened surface. If the content is less than 0.05% by weight, the degree of curing of the roughened surface forming resin film is insufficient, so that the degree of penetration of acid or oxidizing agent into the roughened surface forming resin film increases. The insulation of the film may be impaired. On the other hand, when the content exceeds 10% by weight, an excessive curing agent component may modify the composition of the resin, which may cause a decrease in reliability.

Examples of the other components include fillers such as inorganic compounds and resins which do not affect the formation of the roughened surface. As the inorganic compound, for example,
Examples of the resin include silica, alumina, and dolomite. Examples of the resin include a polyimide resin, a polyacryl resin, a polyamideimide resin, a polyphenylene resin, a melanin resin, and an olefin resin. By incorporating these fillers, the performance of the printed wiring board can be improved by matching the thermal expansion coefficient, improving heat resistance and chemical resistance, and the like.

Further, the resin film for forming a roughened surface is
A solvent may be contained. Examples of the solvent include ketones such as acetone, methyl ethyl ketone and cyclohexanone, ethyl acetate, butyl acetate, and aromatic hydrocarbons such as cellosolve acetate, toluene, and xylene. These may be used alone or in combination of two or more.

(4) Next, while the interlayer resin insulation layer is cured, the interlayer resin insulation layer is exposed and developed or laser-processed to form a via hole opening. When the resin matrix of the resin composition for forming a roughened surface is a thermosetting resin, a polyolefin-based resin, a cycloolefin-based resin, or the like, the opening of the interlayer resin insulating layer is performed using a laser beam, oxygen plasma, or the like. When the resin is used, the exposure and development are performed. In the exposure and development processing, a photomask (a glass substrate is preferable) on which a circular pattern for forming an opening for a via hole is drawn is placed with the circular pattern side in close contact with the photosensitive interlayer resin insulating layer. After that, exposure is performed, and immersion in a developing solution or spraying of the developing solution is performed. 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.

When a via hole opening is provided by using the above laser light, the laser light used may be, for example,
Examples include a carbon dioxide (CO ₂ ) laser, an ultraviolet laser, an excimer laser, and a YAG laser. Of these, excimer lasers and short-pulse carbon dioxide lasers are preferred.

As will be described later, the excimer laser can form a large number of via hole openings at once by using a mask or the like in which through light is formed in a portion where the via hole opening is formed. This is because the short-pulse carbon dioxide laser has less resin residue in the opening and less damage to the resin around the opening.

Further, among the excimer lasers, it is desirable to use a hologram type excimer laser. The hologram method is a method of irradiating a laser beam to a target object through a hologram, a condensing lens, a laser mask, a transfer lens, and the like. The opening can be formed efficiently.

When a 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. The through-hole of the mask in which the through-hole is formed in the portion where the opening for via-hole is formed needs to be 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 0.1
About 2 mm is desirable.

When the opening is formed by a laser beam, particularly when a carbon dioxide gas laser is used, desmearing is preferably performed. The desmear treatment can be performed using an oxidizing agent composed of an aqueous solution such as chromic acid and permanganate. Alternatively, the treatment may be performed using oxygen plasma, a mixed plasma of CF ₄ and oxygen, corona discharge, or the like. The surface can also be modified by irradiating ultraviolet rays using a low-pressure mercury lamp.

(5) Next, if necessary, the surface of the interlayer resin insulating layer provided with the via hole opening is roughened. When the interlayer resin insulating layer is formed using the roughened surface forming resin composition, the interlayer resin insulating layer is roughened by removing heat-resistant resin particles and the like existing on the surface of the roughened surface forming resin composition layer. Alternatively, it is carried out by dissolving and removing with an oxidizing agent. The height of the roughened surface formed by acid treatment or the like is desirably Rmax = 0.01 to 20 μm. 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 metal layer can be removed while ensuring adhesion.

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, when the roughening process is performed, the metal conductor layer exposed from the via hole is hardly corroded. The oxidation treatment is performed using chromic acid,
It is desirable to use permanganate (such as potassium permanganate).

(6) Next, a thin film conductor layer made of a metal such as Cu, Ni, P, Pd, Co and W is formed on the surface of the interlayer resin insulating layer and the opening of the via hole. The thin film conductor layer may be composed of a single metal,
It may be made of more than one kind of metal. Further, the thin film conductor layer may be a single layer, or may be two or more layers. The thickness of this thin-film conductor layer is preferably from 0.1 to 5 μm, more preferably from 0.5 to 2 μm. Further, it is desirable that the thin film conductor layer is formed by performing sputtering, plating, or sputtering and plating.

(7) Next, a roughened surface or the like is formed on the surface of the thin film conductor layer. The roughened surface or the like is formed by performing an etching process, a blackening-reduction process, an electroless plating process, or the like as described above. (8) Subsequently, a plating resist is formed on the thin-film conductor layer including the roughened surface and the like formed in (7). This plating resist is formed by applying a photosensitive dry film on a thin film conductor layer including a roughened surface and the like, and then performing exposure and development treatments.

(9) Next, electroplating is performed using the thin-film conductor layer including the roughened surface and the like formed on the interlayer resin insulating layer as a plating lead to thicken the conductor circuit. The thickness of the electroplated film is preferably 5 to 30 μm. It is desirable to use copper plating as the electroplating. At this time, the via hole opening may be filled with electroplating to form a filled via structure.

(10) After forming the electroplating film, the plating resist is peeled off, and the thin film conductor layer including the roughened surface and the like existing under the plating resist is removed by etching to form an independent conductor circuit. . Examples of the etchant include a sulfuric acid-hydrogen peroxide aqueous solution, ammonium persulfate, sodium persulfate, a persulfate aqueous solution such as potassium persulfate,
An aqueous solution of ferric chloride and cupric chloride, hydrochloric acid, nitric acid, hot dilute sulfuric acid and the like can be mentioned. 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.

(11) If necessary, repeat the steps (3) to (10).
Electroless plating, etching, or the like is performed under the same conditions as in step (3) to form a roughened layer or a roughened surface on the uppermost conductive circuit.

Next, a solder resist resin composition is applied to the substrate surface including the uppermost conductive circuit by a roll coater method or the like, and an opening process such as a laser process, an exposure process, and a developing process is performed, and a curing process or the like is performed. Thus, a solder resist layer is formed. Then, after this, the manufacture of the printed wiring board is completed by forming solder bumps in the openings of the solder resist layer.

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

[0076]

The present invention will be described in more detail below.

Example 1 A. Preparation of resin film made of polyolefin resin composition (i) 104 g of styrene in 500 ml of n-heptane
And 10.8 g of butyllithium were dissolved and heated at 70 ° C. for 3 hours. (ii) 70 ° C. while blowing a mixed gas having a volume ratio of ethylene: butadiene of 3: 1 into the solution subjected to the above treatment.
For 5 hours.

(Iii) Thereafter, I ₂ was further added, and 10
The n-heptane was removed by leaving at 0 ° C. for 1 hour. (iv) The remaining product was washed with acetone to remove unreacted substances and LiI. Thereafter, spherical melanin having a particle size of 0.1 μm and spherical melanin having a particle size of 0.05 μm were mixed at a ratio of 2: 1 and mixed so as to be dispersed without aggregation.

(V) Of the mixture obtained in the step (iv),
After dissolving 50 g again in 500 ml of n-heptane and further dissolving 1 g of benzoyl peroxide, the solution was spread thinly on a polyethylene terephthalate film, and the film was heated to 50 ° C. and further heated at 1 ° C. /
After slowly heating for 100 minutes and reaching 100 ° C., the solvent was removed by allowing to stand for 30 minutes. Thus, 4
A resin film made of a semi-cured polyolefin oligomer having a thickness of 0 μm was obtained.

B. 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 (manufactured by Admatechs, CRS 11)
01-CE) 170 parts by weight and 1.5 parts by weight of a leveling agent (Perenol S4 manufactured by San Nopco) are placed in a container and mixed by stirring to obtain a resin filler having a viscosity of 23 ± 1 ° C. and 40 to 50 Pa · s. Prepared. As a curing agent, an imidazole curing agent (2E, manufactured by Shikoku Chemicals Co., Ltd.)
4MZ-CN) 6.5 parts by weight.

C. Manufacturing method of printed wiring board (1) Glass epoxy resin or BT with a thickness of 0.8 mm
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 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 the above B, within 24 hours after the preparation by the following method, the inside of the through hole 9 and the conductive circuit non-molded portion on one side of the substrate 1 and the conductive circuit 4 A layer of the resin filler 10 was formed on the outer edge.
That is, first, the resin filler was pressed 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 concave conductive circuit non-forming portion using a squeegee, It was dried at 100 ° C. for 20 minutes (FIG. 2).
(C)).

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

In this way, the surface portion of the resin filler 10 formed in the through-hole 9 and the portion where the conductor circuit is not formed and the surface of the lower conductor circuit 4 are flattened, and the resin filler 10 and the side surfaces of the lower conductor circuit 4 are flattened. 4a is firmly adhered through the roughened surface, and the inner wall surface 9a of the through hole 9 and the resin filler 10
Was firmly adhered through the roughened surface to obtain an insulating substrate (see FIG. 2D).

(5) Next, an etching solution is sprayed on both surfaces of the substrate after the treatment of (4), and the surface of the lower-layer conductor circuit 4 once flattened and the land surface of the through hole 9 are Is etched to form the lower conductor circuit 4
The roughened surfaces 4a and 9a were formed on the entire surface of (2) (see FIG. 3A). As an etching solution, 10 parts by weight of an imidazole copper (II) complex, 7 parts by weight of glycolic acid, 5 parts by weight of potassium chloride
An etching solution consisting of parts by weight (Mec etch bond, manufactured by Mec) was used.

(6) Next, the film made of the polyolefin resin composition having a thickness of 40 μm prepared in the above A was pressure-bonded to both surfaces of the substrate at a temperature of 160 ° C. and a pressure of 1 MPa.
The layers were laminated to form an interlayer resin insulating layer 2 made of the above polyolefin-based resin composition (see FIG. 3B). The thickness of the formed interlayer resin insulating layer was 30 μm.

(7) Next, a via hole opening 6 having a diameter of 80 μm was formed in the interlayer resin insulating layer 2 made of a polyolefin resin composition by an excimer laser having a wavelength of 0.248 μm (see FIG. 3C). ). Thereafter, a desmear treatment was performed using oxygen plasma.

(8) Next, SV manufactured by Japan Vacuum Engineering Co., Ltd.
Using −4540, sputtering with Ni as the target was performed at a pressure of 0.6 Pa, a temperature of 80 ° C., a power of 200 W,
This was performed under the conditions of a time of 5 minutes to form the Ni metal layer 12a on the surface of the interlayer resin insulating layer 2 (see FIG. 3D). At this time, the thickness of the formed Ni metal layer 12a was 0.1 μm.

(9) Next, using the above SV-4540,
Sputtering with Cu as the target is performed at a pressure of 0.6.
Pa, a temperature of 80 ° C., a power of 200 W, and a time of 5 minutes, and a 0.5 μm-thick Cu
The metal layer 12b was formed. (See FIG. 4A).

(10) Subsequently, on the surface of the Cu metal layer 12b, a roughened surface having an average roughness Ra of 0.3 μm (shown in FIG. 5) using an etching solution similar to the etching solution used in the above (5). Was formed. The average roughness Ra was measured using a surface roughness profile measuring instrument (Surfcom 130A / Tokyo Seimitsu Co., Ltd.).
480A).

(11) A commercially available photosensitive dry film is stuck on the roughened surface, a mask is placed, exposed at 100 mJ / cm ² , and developed with a 0.8% aqueous sodium carbonate solution. A plating resist 3 having a thickness of 15 μm was provided (see FIG. 4B).

(12) Then, an electro-copper plating film was formed on the non-resist-formed portion under the following conditions to form an electro-copper plating film 13 having a thickness of 15 μm (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 off with a 5% KOH aqueous solution, the Cu metal layer 12b and the Ni metal layer 12a including the roughened surface under the plating resist are plated with sulfuric acid and hydrogen peroxide. The mixture was dissolved and removed by etching to obtain an independent upper-layer conductor circuit 5 (including the via hole 7) (see FIG. 4D).

(14) Subsequently, the above steps (5) to (13) were repeated to form a further upper layer conductor circuit (see FIGS. 5 (a) to 6 (a)). In addition, the steps described above
The surface of the conductor circuit (including the via hole 7) 5 is etched by using the same etching solution as that used in (5) to roughen the surface of the conductor circuit (including the via hole 7). Was formed (see FIG. 6B).

(15) 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 property (molecular weight: 4000), 15 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 15 parts by weight of an imidazole curing agent ( (Shikoku Chemicals, trade name: 2E4MZ-CN)
6 parts by weight, 3 parts by weight of a polyfunctional acrylic monomer (trade name: R604, manufactured by Nippon Kayaku Co., Ltd.), which is a photosensitive monomer, and polyvalent acrylic monomer (trade name: DP, manufactured by Kyoei Chemical Co., Ltd.)
E6A) 1.5 parts by weight and 0.71 part by weight of a dispersion antifoaming agent (manufactured by San Nopco, trade name: S-65) in a container,
A mixed composition was prepared by stirring and mixing, and 2.0 parts by weight of benzophenone (manufactured by Kanto Kagaku) as a photopolymerization initiator and Michler's ketone (manufactured by Kanto Kagaku) as a photosensitizer were added to the mixed composition. Add 0.2 parts by weight and adjust viscosity to 25 ° C
To obtain a solder resist resin composition adjusted to 2.0 Pa · s. 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.

(16) Next, the above-mentioned solder resist composition is applied to both sides of the multilayer wiring board in a thickness of 20 μm,
After performing a drying process under the conditions of 20 ° C. for 20 minutes and 70 ° C. for 30 minutes, a 5 mm-thick photomask on which a pattern of the opening of the solder resist is drawn is brought into close contact with the solder resist layer, and an ultraviolet ray of 1000 mJ / cm ² is applied. Exposure with DM
Development was performed with a TG solution to form an opening having a diameter of 200 μm. Then, at 80 ° C. for 1 hour, and at 100 ° C. for 1 hour.
The solder resist layer is cured by performing heat treatment under the conditions of 120 ° C. for 1 hour and 150 ° C. for 3 hours, and the solder pad portion is opened, and the solder resist layer having a thickness of 20 μm (organic interlayer resin insulation) Layer 14 was formed.

(17) Next, the substrate having the solder resist layer (organic interlayer resin insulating layer) 14 formed thereon was treated with nickel chloride (2.3 × 10 ^-1 mol / l) and sodium hypophosphite (2.8). × 10 ^-1 mol / l) and an electroless nickel plating solution of pH = 4.5 containing sodium citrate (1.6 × 10 ^-1 mol / l) for 20 minutes, and a thickness of 5 μm at the opening. Was formed. further,
The substrate was washed with potassium cyanide (7.6 × 10 ⁻³ mol)
/ L), ammonium chloride (1.9 × 10 ^-1 mol /
l), sodium citrate (1.2 × 10 ⁻¹ mol /
l), sodium hypophosphite (1.7 × 10 ⁻¹ mol /
1) is immersed for 7.5 minutes at 80 ° C. in an electroless plating solution containing
m of the gold plating layer 16 was formed.

(18) Thereafter, a solder paste is printed on the opening of the solder resist layer 14 and reflowed at 200 ° C. to form solder bumps 17, thereby manufacturing a multilayer printed wiring board having the solder bumps 17. FIG. 6C).

(Example 2) In step (10), a roughened surface was formed using an etching solution comprising hydrogen peroxide, sulfuric acid, and tetrazole instead of Mech etch bond manufactured by Mec Corporation. A multilayer printed wiring board was manufactured in the same manner as in Example 1.

Example 3 Instead of the steps (6) to (10), the following steps (1) to (6) are used to form an interlayer resin insulating layer having a via hole opening, A multilayer printed wiring board was manufactured in the same manner as in Example 1 except that a thin film conductor layer having a roughened surface was formed. (1) While increasing the temperature of the resin film for forming a roughened surface formed by the following method to a temperature of 50 to 150 ° C, 0.5MP
a. Vacuum-compression lamination was performed and affixed to form a resin film layer.

Preparation of Roughened Surface Forming Resin Film Bisphenol A type epoxy resin (epoxy equivalent 46
9. Yuka Shell Epoxy Epicoat 1001) 30
Parts by weight, 40 parts by weight of a cresol novolak type epoxy resin (epoxy equivalent: 215, Epicron N-673 manufactured by Dainippon Ink and Chemicals, Inc.) Light KA-705
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, and an epoxy resin composition is added. Was prepared. After applying the obtained epoxy resin composition on a 38 μm-thick PET film using a roll coater so that the thickness after drying becomes 50 μm, the resin film is dried at 80 to 120 ° C. for 10 minutes. Was prepared.

(2) Next, on the resin film layer, a thickness of 1.
Through a mask having a through-hole of 2 mm, a wavelength of 1
With a CO ₂ gas laser of 0.4 μm, the beam diameter is 4.0 m
m, top hat mode, pulse width 8.0 μsec, diameter of the through hole of the mask 1.0 mm, 1-shot, a via hole opening of 80 μm was formed in the resin film layer as an interlayer resin insulation layer. .

(3) The substrate in which the opening for the via hole was formed was placed in a solution at 80 ° C. containing 60 g / l of permanganate.
By immersing for 0 minutes to dissolve and remove the epoxy resin particles present on the surface of the interlayer resin insulating layer, a roughened surface was formed on the surface including the inner wall surface of the via hole opening.

(4) 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 to the surface of the substrate subjected to the surface roughening treatment (roughening depth: 3 μm), catalyst nuclei adhere to the surface of the interlayer resin insulating layer (including the inner wall surface of the via hole opening). I let it. That is, the substrate was immersed in a catalyst solution containing palladium chloride (PbCl ₂ ) and stannous chloride (SnCl ₂ ) to deposit a palladium metal to provide a catalyst.

(5) Next, the substrate is immersed in an electroless copper plating aqueous solution having the following composition to form an electroless copper plating film having a thickness of 0.6 to 3.0 μm on the surface of the interlayer resin insulating layer. did. [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 100 mg / l Polyethylene glycol (PEG) 0.10 g / l [Electroless plating conditions] 40 minutes at a liquid temperature of 34 ° C

(6) Subsequently, the surface of the electroless copper plating film is
Using a Mec etch bond manufactured by Mec Co., Ltd., the average roughness R
a formed a roughened surface of 0.3 μm.

(Example 4) In step (6), a roughened surface was formed by using an etching solution consisting of aqueous hydrogen peroxide, sulfuric acid, and tetrazole instead of Mech etch bond manufactured by Mec Corporation. A multilayer printed wiring board was manufactured in the same manner as in Example 3.

Comparative Example 1 A multilayer printed wiring board was manufactured in the same manner as in Example 1 except that the roughened surface was not formed in the step (10). After the photosensitive dry film was exposed and developed, the cross section of the substrate provided with the plating resist 3 was observed with a microscope. As a result, the shape of the plating resist was an undercut shape having a void at the bottom.

With respect to the multilayer printed wiring boards obtained in Examples 1 to 4 and Comparative Example 1, the multilayer printed wiring boards were cut with a cutter, and their cross sections were observed with a microscope.
In the multilayer printed wiring boards of Examples 1 to 4, no conductive circuit having a trapezoidal cross section was found, whereas in the multilayer printed wiring board of Comparative Example 1, a conductive circuit having a partially widened bottom was seen. Was done.

Further, with respect to the multilayer printed wiring boards obtained in Examples 1 to 4 and Comparative Example 1, a heat cycle in which a heat cycle of holding at −55 ° C. for 30 minutes and then holding at 125 ° C. for 30 minutes is repeated 1,000 times. Was performed, the multilayer printed wiring board was cut with a cutter, and the cross section was observed with a microscope. As a result, in the multilayer printed wiring boards of Examples 1 to 4, there was no peeling of the conductor circuit and no crack was observed in the interlayer resin insulating layer, whereas in the multilayer printed wiring board of Comparative Example 1, some of A peeled conductor circuit was observed, and cracks were observed in a part of the interlayer resin insulating layer.

Further, the multilayer printed wiring boards obtained in Examples 1 to 4 and Comparative Example 1 were subjected to a heat cycle test and then to a conduction test.
In the multilayer printed wiring board of Comparative Example 1, the conduction failure did not occur in the multilayer printed wiring board of Comparative Example 1.
In some cases, conduction failure occurred.

[0113]

As described above, according to the method for manufacturing a multilayer printed wiring board of the present invention, since the roughened surface or the like is formed on the surface of the thin film conductor layer, the physical properties of the surface of the thin film conductor layer become uniform. When the photosensitive dry film is pressed on the thin film conductor layer, the contact area between the thin film conductor layer and the photosensitive dry film is improved by increasing the contact area between the two,
When a photosensitive dry film is attached on the thin film conductor layer, the photosensitive dry film does not swell or the like, and a rectangular plating resist excellent in adhesion to the thin film conductor layer can be formed. . Therefore, when a conductor circuit is formed in the plating resist non-formed portion after the plating resist is formed, a conductor circuit having a rectangular cross section can be formed, and there is no possibility that a short circuit occurs between adjacent conductor circuits. A multilayer printed wiring board with excellent connection reliability can be manufactured under heat cycle conditions or under high temperature and high humidity without signal delay or signal error.

[Brief description of the drawings]

FIGS. 1A to 1D are cross-sectional views showing a part of a manufacturing process of a multilayer printed wiring board using the manufacturing method of the present invention.

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

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

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

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

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

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

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Substrate 2, 102 Interlayer resin insulation layer 3 Plating resist 4 Lower conductor circuit 4a Roughened surface 5 Upper layer conductor circuit 6 Via hole opening 7 Via hole 8 Copper foil 9 Through hole 9a Roughened surface 10 Resin filler 12a Ni metal layer 12b Cu metal layer 13 electroplating film 14 solder resist layer 15 nickel plating film 16 gold plating film 17 solder bump 18 photosensitive dry film 21 mask 22 roughening layer 105 conductor circuit 112 thin film conductor layer 113 electroplating layer

 ──────────────────────────────────────────────────続 き Continued on the front page F-term (reference) 5E343 AA02 AA12 AA15 AA17 AA36 AA37 BB16 BB21 BB71 CC33 CC43 CC50 CC62 DD33 DD43 DD76 EE17 EE52 ER16 ER18 GG04 5E346 AA05 AA06 AA12 AA15 AA32 BB01 CC04 CC33 DD33 EE38 GG17 GG22 GG23 GG27 HH11

Claims (2)

[Claims] A step of attaching a photosensitive dry film on the interlayer resin insulating layer on which the thin film conductor layer is formed, a step of exposing and developing the photosensitive dry film to form a plating resist, and A method of manufacturing a multilayer printed wiring board including a step of forming a conductor circuit in a plating resist non-formed portion, wherein, after forming a roughened surface or a roughened layer on the surface of the thin film conductor layer, A method for manufacturing a multilayer printed wiring board, comprising attaching a dry film. 2. An average roughness Ra of the roughened surface or the roughened layer.
The method for manufacturing a multilayer printed wiring board according to claim 1, wherein is 0.01 to 1 µm.