JP2000022334A - Multilayer printed wiring board and its manufacture - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a multilayer printed wiring board which does not cause a damage to a covering plated layer and besides is excellent in crack resistance under conditions of heat cycle or the like. SOLUTION: In a multilayer printed wiring board which has such a structure that a conductor circuit is made through an interlayer resin insulating layer on a board, that the substrate is provided with a through hole, and that the through hole is charged with a filler, a conductor layer to cover the exposed face from the through hole of filling material is made right above the through hole, and a roughened layer is made all over the surface including the side face, in the conductor circuit positioned in the same layer as this conductor layer, and an interlayer resin insulating layer which fills the recess between the conductors and whose surface is flat is made at the surface of the roughened layer.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a multilayer printed wiring board and a method of manufacturing the same, and more particularly to a multilayer printed wiring board which can easily realize high density wiring and through holes and has excellent heat cycle resistance. suggest.

[0002]

2. Description of the Related Art Generally, a through hole for electrically connecting a front surface and a back surface is formed in a core substrate of a double-sided multilayer printed wiring board. However, this through hole becomes a dead space, and the increase in wiring density is significantly impaired.

The connection between the via hole and the via hole formed in the core substrate is performed by providing a pad for connecting the via hole on a land of the through hole. However, this pad hinders the pitch of the through-holes from being reduced, and the density of the through-holes is significantly impaired.

[0004] In order to improve the formation density of wiring and through holes, the applicant has first formed a conductor circuit on a substrate via an interlayer resin insulating layer, and provided the substrate with through holes. In a multilayer printed wiring board having a structure in which a filler is filled in the through hole, a conductor layer is formed immediately above the through hole to cover an exposed surface of the filler from the through hole. Above, we proposed a multilayer printed wiring board with via holes connected.

[0005] In the multilayer printed wiring board according to this proposal, first, a through hole is formed in a core substrate, the surface is roughened by an oxidation-reduction treatment or the like, and then a filler is filled in the through hole to make it flat. , Plating (lid plating) and etching to form a conductor layer (hereinafter simply referred to as a “lid plating layer”) and a conductor circuit that cover the exposed surface of the filler from the through-hole, and furthermore, these conductors After forming a roughened layer on the surface by redox treatment or the like, filling the recesses between the conductors with a filler, polishing the filler surface and flattening the surface, then using an interplate (Cu-Ni-P of Ebara Uzilite) After roughening plating such as alloy roughening plating made of an alloy, an interlayer resin insulating layer is formed thereon (see FIG. 1).

[0006]

However, in this method, there is a problem that the lid plating layer is damaged by the polishing treatment for planarization performed after the filling material is embedded. Further, in the multilayer printed wiring board manufactured by this method, when the roughened layer on the surface of the conductor circuit is composed of a roughened alloy plating layer by an interplate, and the roughened layer on the side surface of the conductor circuit is composed of a blackening reduction layer, The interlayer resin insulating layer joined to the conductor via the roughened layer has a problem that cracks are generated by a heat cycle test or the like because the form of the roughened layer is different.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problems, and a main object of the present invention is to provide a multilayer print capable of realizing a high density of wirings and through holes without causing loss of a lid plating layer. It is to propose a method for manufacturing a wiring board. Another object of the present invention is to provide a multilayer printed wiring board having excellent crack resistance under conditions such as a heat cycle.

[0008]

Means for Solving the Problems The inventors of the present invention have made intensive studies for realizing the above-mentioned object, and as a result, have completed the present invention having the following constitution as a summary. (1) The multilayer printed wiring board of the present invention is formed by forming a conductor circuit on a substrate via an interlayer resin insulating layer, the substrate is provided with through holes, and the through holes are filled with a filler. In the multilayer printed wiring board having the structure described above, a conductor layer covering the exposed surface of the filler from the through hole is formed immediately above the through hole, and the conductor layer and a conductor circuit located on the same layer as the conductor layer are formed on the conductor layer. Is characterized in that a roughened layer is formed on the entire surface including the side surfaces, and the surface of the roughened layer is filled with concave portions between conductors, and an interlayer resin insulating layer having a flat surface is formed. I do.

(2) The method for producing a multilayer printed wiring board of the present invention comprises at least the following steps: Forming a through hole in the substrate; Providing a roughened layer on the inner wall of the through hole; Filling the through hole with a filler; Forming a conductor layer directly above the through hole so as to cover an exposed surface of the filler from the through hole; Providing a roughened layer on the entire surface including the side of the conductor layer and the conductor circuit located on the same layer; Providing a layer of an uncured interlayer resin insulating agent, heat-pressing the layer of the interlayer resin insulating agent to flatten its surface, and then performing a curing process to form an interlayer resin insulating layer; Forming a conductor circuit on the interlayer resin insulation layer,
It is characterized by including.

In the manufacturing method described in the above (2), the roughened layer in the step is preferably an oxidation-reduction treated layer. In the above step, when a photosensitive interlayer resin insulating layer is formed, a light-transmitting film is attached to a layer surface of the interlayer resin insulating material before hot pressing, and the interlayer resin insulating material is interposed through the light-transmitting film. It is preferred that the surface of the layer is flattened by a heat press, cured by exposure, and then the light-transmitting film is removed and developed. The heating press in the above step is preferably performed by pressing a metal plate or a metal roll while heating the layer of the interlayer resin insulating material. In the step, the heating press of the layer of the interlayer resin insulating material containing an epoxy resin as a main component is performed at a temperature of 40 to 60.
° C., a pressure 3.5~6.5kgf / cm ^2, it is preferable to carry out under conditions of press time 30 to 90 seconds. Further, it is preferable that an opening is provided in the interlayer resin insulating layer at a portion located immediately above the through hole to form a conductor circuit and a via hole. Further, as the filler, it is preferable to use a filler composed of metal particles, a thermosetting or thermoplastic resin and a curing agent.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention is characterized in that an interlayer resin insulation layer is formed directly on the surface of a substrate having irregularities by a method such as coating without filling a recess between conductors with a filler. . Further, in the present invention, after forming a layer of an uncured interlayer resin insulating agent on the surface of the substrate having irregularities, heat pressing with a metal plate or a metal roll or the like is performed to flatten the surface of the obtained interlayer resin insulating layer. There is a feature in the point. More preferably, on a surface of a substrate having irregularities, a photosensitive interlayer insulating resin containing an epoxy resin as a main component is applied, and then a light-transmitting film such as a PET film is laminated, and the temperature is 40 to
The surface is flattened by pressing under the conditions of 60 ° C., a pressure of 3.5 to 6.5 kgf / cm ² , and a pressing time of 30 to 90 seconds.

Thus, the polishing step for flattening the substrate surface can be omitted, and the problem that the lid plating layer is lost can be solved. In addition, it is possible to prevent dust and foreign matter from being mixed by polishing. Further, according to the present invention, due to the unevenness of the surface of the interlayer resin insulating layer, the formation of the opening for forming the via hole due to the exposure and the development does not occur, and the mounting failure such as the mounting failure of the IC chip or the like does not occur. Furthermore, since the light-transmitting film is attached to the interlayer resin insulating layer and exposed and cured, the inhibition of the curing reaction by oxygen is prevented, so that the film can be prevented from being reduced even after the development processing. Even if the roughening treatment is performed to form a shallow roughened layer, the peel strength does not decrease.

Another feature of the present invention resides in that the interface between the conductor circuit and the interlayer resin insulating layer is all constituted by the same roughened layer. This can prevent cracks at the interface between the conductor circuit and the interlayer resin insulation layer due to the difference in the roughened form of the surface and side surfaces of the conductor.

As described above, according to the present invention, since the surface of the conductor is roughened in one step without filling the recess between the conductors with the filler, the manufacturing process is greatly reduced.
Thereby, the manufacturing cost of the multilayer printed wiring board can be reduced.

Here, the reason why the surface of the interlayer resin insulating layer of the substrate is flattened by pressing is as follows. That is, when an uncured interlayer resin insulating layer is directly applied to the uneven surface of the substrate by a roll coater or the like, the formed interlayer resin insulating layer also has surface unevenness. For example, as shown in FIG. 2, an interlayer resin insulating layer formed in a region where the area of the conductor circuit is large is formed in a region where the thickness of the conductor circuit is relatively large and the area of the conductor circuit is small (conductor circuit pattern region). The interlayer resin insulating layer becomes thin because the interlayer resin insulating agent enters between the patterns. That is, the thickness of the interlayer resin insulation layer changes due to the surface irregularities of the inner conductor circuit, and irregularities occur on the surface.

The pressing conditions in this flattening treatment are as follows: temperature: 40 to 60 ° C., pressure: 3.5 to 6.5 kgf / cm ² , and time: 30 to 90 seconds. That is,
The press conditions are less than 40 ° C, pressure less than 3.5Kgf / cm ² ,
If the pressing time is less than 30 seconds, sufficient flatness cannot be obtained. On the other hand, if the pressing temperature exceeds 60 ° C., the curing of the interlayer resin insulating agent may proceed before exposure and development,
If the pressing pressure exceeds 6.5 kgf / cm ² , the interlayer insulating resin may flow out of the substrate, and the pressing
If the time exceeds 2 seconds, the productivity is expected to decrease in consideration of the conventional exposure time and post-bake time.

In the present invention, it is preferable that a roughened layer, more preferably, a roughened layer formed by an oxidation-reduction treatment is formed on the conductor surface of the inner wall of the through hole. The reason for this is that the filler and the through-hole are in close contact with each other via the roughened layer, and no gap is generated. If there is a gap between the filler and the through hole, the conductor layer formed by electrolytic plating directly above it will not be flat, or the air in the gap will thermally expand, causing cracks and peeling. Or cause water to accumulate in the voids, causing migration or cracks. In this regard, the formation of the roughened layer can prevent such defects from occurring.

For example, the roughened layer formed by the oxidation-reduction treatment may be used as an oxidation bath such as NaOH (20 g / l), NaClO ₂ (50 g / l),
Na ₃ PO ₄ (15.0 g / l) aqueous solution, NaOH
(2.7 g / l), formed using an aqueous solution of NaBH ₄ (1.0 g / l).

In the present invention, the surface of the conductor layer (lid plating layer) covering the exposed surface of the filler in the through-hole and the surface of another conductor circuit located on the same layer as the conductor layer are provided with Cu-Ni-
A roughened layer of alloy plating made of P (for example, Ebara Uzilite Interplate), a roughened layer formed by oxidation-reduction treatment, or a roughened layer formed by processing with an etching solution called “Mech etch bond” manufactured by Mec Co., Ltd. Is formed.
The reason is that the roughened layer can improve the adhesion to the interlayer resin insulating layer and the via hole.
In particular, in the present invention, the same roughened layer is also formed on the side surface of the conductor. Thereby, cracks that are generated perpendicularly toward the interlayer resin insulating layer from these interfaces due to insufficient adhesion to the interlayer resin insulating layer due to the difference between the roughened layer on the surface and the side surface of the conductor can be suppressed. .

Among these roughened layers, the roughened alloy plating layer made of Cu-Ni-P is a needle-shaped alloy layer, for example, 1 to 40 g / l of copper sulfate and 0.1 to 6.0 g / l of nickel sulfate. ,
Citric acid 10-20 g / l, hypophosphite 10-100 g / l,
It is formed using a plating bath having a liquid composition of an aqueous solution of boric acid 10 to 40 g / l and an acetylene-containing polyoxyethylene surfactant of 0.01 to 10 g / l.

The roughened layer may be covered with a layer of a metal or a noble metal whose ionization tendency is larger than copper and equal to or less than titanium. This is because these metal or noble metal layers cover the roughened layer and can prevent the conductor circuit from dissolving due to a local electrode reaction that occurs when the interlayer resin insulating layer is roughened. The thickness of the layer is preferably 0.1 to 2 μm. Examples of such a metal include at least one selected from titanium, aluminum, zinc, iron, indium, thallium, cobalt, nickel, tin, lead, and bismuth. Noble metals include gold, silver, platinum and palladium. Of these, tin is particularly preferred. Tin is advantageous because it can form a thin layer by electroless displacement plating and can follow the roughened layer. In the case of tin, tin borofluoride-thiourea or tin chloride-thiourea liquid is used. Then, a Sn layer having a thickness of about 0.1 to 2 μm is formed by the substitution reaction of Cu—Sn. In the case of a noble metal, a method such as sputtering or vapor deposition can be adopted.

In the present invention, the filler is preferably composed of metal particles, a thermosetting or thermoplastic resin and a curing agent, and a solvent may be added as necessary. Metal particles include copper, gold, silver, aluminum, nickel,
Titanium, chromium, tin / lead, palladium, platinum and the like can be used. The metal particles have a particle size of 0.1 to
50 μm is preferred. The reason is that if the thickness is less than 0.1 μm, the copper surface is oxidized and the wettability to the resin is deteriorated.
If the thickness exceeds μm, printability deteriorates. Also,
The compounding amount of the metal particles is preferably 30 to 90% by weight based on the total amount. The reason for this is that if the amount is less than 30% by weight, the adhesion of the lid plating deteriorates, while if it exceeds 90% by weight, the printability deteriorates. Examples of the resin used include epoxy resin, phenol resin, polyimide resin, fluorine resin such as polytetrafluoroethylene (PTFE), bismaleimide triazine (BT) resin, FEP, PFA, PP
S, PEN, PES, nylon, aramid, PEEK,
PEKK, PET, etc. can be used. As a curing agent,
Curing agents such as imidazole, phenol and amine curing agents can be used. As the solvent, NMP (normal methylpyrrolidone), DMDG (diethylene glycol dimethyl ether), glycerin, water, 1- or 2- or 3-
, Cyclohexanol, cyclohexanone, methyl cellosolve, methyl cellosolve acetate, methanol, ethanol, butanol, propanol, bisphenol A type epoxy and the like can be used.

It is desirable to use a filler containing inorganic ultrafine particles as the filler. The reason is that sedimentation of the metal particles can be prevented. As the inorganic ultrafine particles, it is desirable to use silica, alumina, silicon carbide, and mullite, and among them, silica is most suitable.
The average particle diameter of the inorganic ultrafine particles is desirably 1 to 1000 nm, preferably 2 to 100 nm. The reason for this is
This is because, since the particle diameter is fine, a bond presumed to be a hydrogen bond can be formed in a network without impairing the filling property of the through-hole, and the particulate matter can be trapped. The blending amount of the inorganic ultrafine particles is desirably 0.1 to 5% by weight based on the total solid content of the resin composition. The reason is that the sedimentation of the metal particles can be prevented without impairing the filling property. It is desirable that this filler be non-conductive (specific resistance of 1.48 Ω · cm or more).
This is because the non-conductive material has a smaller curing shrinkage and is less likely to peel off from the conductor layer (lid plating layer) or via hole.

In the present invention, as the interlayer resin insulating layer, a thermosetting resin (including one obtained by sensitizing a part or all of the thermosetting group), a thermoplastic resin, or a thermosetting resin (including a thermosetting group). (Including those partially or entirely sensitized) and a thermoplastic resin. As thermosetting resin, epoxy resin, polyimide resin,
Phenol resin, thermosetting polyphenylene ether (P
PE) can be used. In particular, as the epoxy resin, a novolak-type epoxy resin, an alicyclic epoxy resin, or the like can be used. In addition, this thermosetting resin,
It is preferable to impart a photosensitivity by substituting a part of the thermosetting functional group with a photosensitive group. The reason for this is that if a resin insulating agent containing a thermosetting resin with photosensitivity as a resin component is used, an opening for a via hole can be easily formed in the interlayer resin insulating layer by exposure and development. is there. When sensitizing a part or all of the thermosetting group, a part or all of the thermosetting group is reacted with methacrylic acid, acrylic acid, or the like to be acrylated. Of these, epoxy resin acrylate is most suitable. As the thermoplastic resin, a fluorine resin such as polytetrafluoroethylene (PTFE),
Polyethylene terephthalate (PET), polysulfone (PSF), polyphenylene sulfide (PPS),
Thermoplastic polyphenylene ether (PPE), polyether sulfone (PES), polyetherimide (PE
I), polyphenylene sulfone (PPES), tetrafluoroethylene hexafluoropropylene copolymer (FEP),
Fluorinated ethylene perfluoroalkoxy copolymer (PF
A), polyethylene naphthalate (PEN), polyetheretherketone (PEEK), polyolefin-based resin and the like can be used. As a composite of a thermosetting resin and a thermoplastic resin, epoxy resin-PES, epoxy resin-
PSF, epoxy resin-PPS, epoxy resin-PPE
S or the like can be used.

In the present invention, a glass cloth impregnated resin composite can be used as the interlayer resin insulating layer. As the glass cloth impregnated resin composite, glass cloth impregnated epoxy, glass cloth impregnated bismaleimide triazine,
Glass cloth impregnated PTFE, glass cloth impregnated PPE,
Examples include glass cloth impregnated polyimide.

In the present invention, an adhesive for electroless plating can be used as the interlayer resin insulating layer. As the adhesive for electroless plating, heat-resistant resin particles that are soluble in a cured acid or oxidizing agent are dispersed in an uncured heat-resistant resin that becomes hardly soluble in an acid or an oxidizing agent by the curing treatment. Is best. The reason for this is that 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, the heat-resistant resin particles which have been particularly hardened include a heat-resistant resin powder having an average particle diameter of 10 μm or less, and an average particle diameter of 2 μm.
Aggregated particles obtained by aggregating the following heat-resistant resin powder, a mixture of a heat-resistant resin powder having an average particle size of 2 to 10 μm and a heat-resistant resin powder having an average particle size of 2 μm or less, and an average particle size of 2 to 10 μm
m, a pseudo particle obtained by adhering at least one of a heat-resistant resin powder or an inorganic powder having an average particle diameter of 2 μm or less to the surface of the heat-resistant resin powder having an average particle diameter of 0.1 to 0.8 μm.
m heat resistant resin powder and average particle size exceeding 0.8 μm and 2 μm
Mixture with heat-resistant resin powder of less than 0.1, average particle size 0.1 ~
It is desirable to use at least one selected from heat-resistant resin powder of 1.0 μm. This is because they can form more complex anchors. As the heat-resistant resin used in the adhesive for electroless plating, the above-mentioned thermosetting resin, thermoplastic resin, or a composite of the thermosetting resin and the thermoplastic resin can be used.

In the present invention, it is desirable that the lid plating layer formed on the substrate and the conductor circuit formed on the interlayer resin insulating layer be connected by via holes. In this case, the via hole is preferably filled with a plating film or a conductive paste.

Hereinafter, the method for producing the multilayer printed wiring board of the present invention will be specifically described by way of an example. The method described below relates to a method of manufacturing a multilayer printed wiring board by a semi-additive method, but the method of manufacturing a multilayer printed wiring board in the present invention employs a full additive method, a multi-lamination method, and a pin lamination method. can do.

(1) Formation of through hole First, a through hole is drilled in a substrate, and electroless plating is applied to the wall surface of the through hole and the surface of the substrate to form a through hole. As the substrate, a resin substrate such as a glass epoxy substrate, a polyimide substrate, a bismaleimide-triazine resin substrate, a fluororesin substrate, or a copper-clad laminate of these resin substrates, a ceramic substrate, a metal substrate, or the like can be used. In particular, when the dielectric constant is considered, it is preferable to use a double-sided copper-clad fluororesin substrate. This substrate is obtained by thermocompression bonding a copper foil having one surface roughened to a fluororesin substrate such as polytetrafluoroethylene. Copper plating is preferred as the electroless plating. In the case of a substrate with poor plating coverage, such as a fluororesin substrate, surface modification such as treatment with a pretreatment agent made of organometallic sodium (trade name: Junko, Tetra-etch), plasma treatment, or the like is performed.

[0031] Next, electrolytic plating is performed for thickening. Copper plating is preferable as the electrolytic plating. . Further, a roughening layer is provided by roughening the inner wall of the through hole and the surface of the electrolytic plating film. The roughened layer is formed by an oxidation-reduction treatment.

(2) Filling of filler The filler having the above-described component composition is filled in the through holes formed in (1). Specifically, the filler is filled in the through-hole by applying by a printing method onto a substrate on which a mask having an opening provided in the through-hole is placed, and then the filler is dried and cured.

A metal surface modifier such as a silane coupling agent may be added to the filler to increase the adhesion between the metal particles and the resin. In addition, as other additives, an antifoaming agent such as an acrylic antifoaming agent or a silicon-based antifoaming agent, or an inorganic filler such as silica, alumina, or talc may be added. Further, a silane coupling agent may be attached to the surface of the metal particles.

Such a filler is printed, for example, under the following conditions. That is, using a printing mask plate of a Tetron mesh plate and a square squeegee at 45 ° C., the viscosity of the Cu paste: 1
Printing is performed under the conditions of 20 Pa · s, squeegee speed: 13 mm / min, and squeegee pushing amount: 1 mm.

[0035] The filler protruding from the through hole and the roughened layer on the surface of the electrolytic plating film on the substrate are removed by polishing to flatten the substrate surface. Polishing is preferably performed using a belt sander or buffing.

(3) Formation of conductor layer After applying catalyst nuclei to the surface of the substrate planarized in the above (2), electroless plating and electrolytic plating are performed, an etching resist is further formed, and the resist non-formed portion is etched, so that the conductor circuit portion and the lid are formed. A plating layer portion is formed. As the etchant, an aqueous solution of sulfuric acid-hydrogen peroxide, an aqueous solution of persulfate such as ammonium persulfate, sodium persulfate, or potassium persulfate, or an aqueous solution of ferric chloride or cupric chloride is preferable.

[0037] Then, after removing the etching resist to form an independent conductor circuit and a lid plating layer, a roughened layer is formed on the surface of the conductor circuit and the lid plating layer by needle-like alloy plating using an interplate. When a roughened layer is formed on the surface of the conductor circuit and the lid plating layer,
Since the conductor has excellent adhesion to the interlayer resin insulation layer,
Cracks originating from the interface between the side surface or surface of the conductor circuit and the lid plating layer and the resin insulating layer do not occur. On the other hand, the adhesion of the lid plating layer to via holes that are electrically connected is improved.

The following steps can be adopted as a method for forming the conductor layer. That is, a plating resist is formed on the substrate after the steps (1) and (2), and then a portion where no resist is formed is subjected to electrolytic plating to form a conductor circuit and a lid plating layer portion. Then, after forming a solder plating film using an electrolytic solder plating solution composed of tin borofluoride, lead borofluoride, borofluoric acid, and peptone, the plating resist is removed, and the electroless plating film and copper under the plating resist are removed. The foil is etched away to form an independent pattern, and the solder plating film is dissolved and removed with a borofluoric acid aqueous solution to form a conductor layer.

(4) Formation of interlayer resin insulation layer. A layer of an interlayer resin insulating agent is formed on the wiring board thus manufactured. As the interlayer resin insulating agent, a thermosetting resin, a thermoplastic resin, or a composite of a thermosetting resin and a thermoplastic resin can be used. In the present invention, the above-described adhesive for electroless plating can be used as the interlayer resin insulating material. The interlayer resin insulating layer is formed by applying an uncured liquid of these resins, or by laminating a film-shaped resin by thermocompression bonding.

[0040] Next, when an uncured interlayer resin insulating agent (adhesive for electroless plating) is applied, the layer of the interlayer resin insulating agent is dried. At the end of this process, since the interlayer resin insulating layer provided on the conductor circuit of the substrate is not filled with resin between the conductor circuits, the thickness of the interlayer resin insulating layer on the conductor circuit pattern area is reduced. Is thin, and the thickness of the interlayer resin insulating layer on the region where the area of the conductor circuit is large is large, and unevenness is generated (see FIG. 4D).

[0041] Next, the layer of the interlayer resin insulating material in the uneven state is pressed (heat-pressed) while heating using a metal plate or a metal roll, and the surface thereof is flattened (see FIG. 4E). The metal plate and metal roll used here are preferably made of stainless steel. The reason is that it has excellent corrosion resistance. The heating press is performed by sandwiching a substrate provided with a layer of an interlayer resin insulating material with a metal plate or a metal roll and pressing in a heating atmosphere. By this heating press, the resin of the interlayer insulating material flows, and the layer surface of the interlayer resin insulating material becomes flat. The heating temperature, pressure and time in this heating press differ depending on the resin used for the interlayer resin insulating agent. For example, when a composite of epoxy resin acrylate and polyether sulfone is used as a resin matrix, and an adhesive for electroless plating using epoxy resin particles as heat-resistant resin particles is used as an interlayer resin insulating agent, the heating temperature is 60 to 70. It is preferable that the temperature is 15 ° C., the pressure is 15 to 25 kgf / cm ² , and the time is 15 to 25 minutes.

When a metal roll is used, it can be heated and pressed while being conveyed, which is advantageous from the viewpoint of mass productivity. In particular, it is advantageous to use a combination of an elastic roll such as rubber and a metal roll. For example,
First, hot pressing is performed with a rubber roll, and then hot pressing is performed with a metal roll. In this case, the substrate provided with the interlayer resin insulating layer is preheated by the first rubber roll, and the preheated substrate is flattened by the metal roll.

In the present invention, if the interlayer resin insulating material is photosensitive, a light-transmitting film can be attached on the layer of the interlayer resin insulating material before hot pressing, if necessary. This translucent film is used to prevent oxygen from hindering the reaction during the photopolymerization reaction, resulting in a decrease in film thickness during development and a decrease in peel strength. Therefore, even at a shallow anchor depth, no decrease in peel strength is observed. The translucent film is desirably a thermoplastic resin film, such as polyethylene terephthalate (PET) or polyethylene (P).
E), a film of polyvinyl alcohol (PVA), polyetheretherketone (PEEK), polyethersulfone (PES), polypropylene (PP), polyvinyl chloride (PVC) and the like are preferable.

It is desirable that these films have an adhesive applied to the surface on the sticking side. The reason is that adhesion to the interlayer resin insulating layer can be ensured.
This pressure-sensitive adhesive is not particularly limited, but "Satoshi Ibouchi,
Komatsu Koei, Kitazaki Yasuaki, edited by the Industrial Research Council, Adhesive Utilization Note "can be used. For example, natural rubber-based, styrene-butadiene-based, polyisobutylene-based, isoprene-based, acrylic-based, acrylic emulsion-based, silicone-based, and natural rubber-butadiene latex-based pressure-sensitive adhesives can be used. Specifically, an adhesive having the following composition can be used.・ Natural rubber 100 parts by weight Natural rubber tackifier resin 150 to 120 parts by weight Zinc flower 25 to 50 parts by weight Calcium carbonate 35 to 60 parts by weight Carbon black 部 15 parts by weight Antioxidant 1.51.5 parts by weight Sulfur 0.5 to 2.25 parts by weight Parts ・ Styrene-butadiene rubber latex 100 parts by weight High melting point tackifier 89 parts by weight Soap-forming resin acid 5.6 parts by weight Antioxidant 4.8 parts by weight Ammonia water 0.7 parts by weight Water 151 parts by weight ・ Polyisobutylene-based polyisobutylene 100 parts by weight Polybutene 10 parts by weight White oil 20 parts by weight ・ Isoprene-based Kuraray, trade name: Kuraprene IR-10 ・ Acrylics 2-ethylhexyne acrylate 78 parts by weight Methyl acrylate 20 parts by weight Maleic anhydride 2 parts by weight Hexamethylenediamine 0.5 parts by weight Parts ・ Acrylic emulsion 2-ethylhexyl acrylate 70 parts by weight Vinyl acetate 30 parts by weight Acrylic acid 2 parts by weight ・ Silicone silicone rubber 100 parts by weight Silicone resin 80-120 parts by weight Condensation catalyst 0.01-0.5 parts by weight Solvent 100-150 parts by weight

In the present invention, the light-transmitting film may be adhered to the interlayer resin insulating layer in the uneven state, and this may be heated and pressed (see FIG. 4E). A light-transmitting film may be attached after flattening the layer of the resin insulating material by hot pressing. Adhering a light-transmitting film before flattening is advantageous because the resin does not adhere to the metal plate.

[0046] Then, the interlayer resin insulating layer is cured to form an interlayer resin insulating layer, and an opening for forming a via hole is formed in the interlayer resin insulating layer in order to secure electrical connection between the upper conductor circuit and the through hole. Is provided. The opening for forming the via hole is formed by exposure and development when the interlayer resin insulating material is made of a photosensitive resin, and is formed by laser light when the interlayer resin insulating material is made of a thermosetting resin or a thermoplastic resin. At this time, the laser light used includes a carbon dioxide laser, an ultraviolet laser, an excimer laser, and the like. If holes are formed by laser light, desmearing may be performed. This desmear treatment can be performed using an oxidizing agent composed of an aqueous solution such as chromic acid or permanganate, or may be performed using oxygen plasma or the like.

[0047] The surface of the interlayer resin insulating layer provided with the opening for forming the via hole is roughened as necessary. When the above-described adhesive for electroless plating is used as an interlayer resin insulating layer, the surface is treated with an acid or an oxidizing agent to selectively dissolve or decompose only the heat-resistant resin particles present on the surface of the adhesive layer. Remove and roughen. Further, even when a thermosetting resin or a thermoplastic resin is used, a surface roughening treatment using an oxidizing agent selected from aqueous solutions such as chromic acid and permanganate is effective. In the case of a resin such as a fluororesin (such as polytetrafluoroethylene) which is not roughened by an oxidizing agent, the surface can be roughened by plasma treatment or tetraetch. At this time, the depth of the roughened surface is 1 to 5
About μm is good. Here, examples of the acid include phosphoric acid, hydrochloric acid, sulfuric acid, and organic acids such as formic acid and acetic acid.
In particular, it is desirable 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. On the other hand, as the oxidizing agent, it is desirable to use an aqueous solution of chromic acid or permanganate (such as potassium permanganate).

(5) Formation of conductor circuit A catalyst nucleus for electroless plating is applied to a wiring board having a roughened surface of the interlayer resin insulating layer. Generally, the catalyst core is a palladium-tin colloid, and the substrate is immersed in this solution,
The catalyst core is fixed on the resin surface by drying and heating. Further, a metal nucleus can be used as a catalyst nucleus by being driven into the resin surface by CVD, sputtering, or plasma. in this case,
A metal nucleus is embedded in the resin surface, and plating is deposited around the metal nucleus to form a conductive circuit. Therefore, the resin is hard to be roughened, and a resin such as a fluororesin (polytetrafluoroethylene) is used. Even if the resin has poor adhesion to the conductor circuit, adhesion can be ensured. As this metal nucleus,
At least one selected from palladium, silver, gold, platinum, titanium, copper and nickel is preferred. The amount of metal nuclei is preferably 20 μg / cm ² or less. If the amount exceeds this amount, metal nuclei must be removed.

[0049] Next, electroless plating is performed on the surface of the interlayer resin insulating layer, and a thin electroless plated film having irregularities along the rough surface is formed on the entire roughened surface. At this time, the thickness of the electroless plating film is 0.1 to 5 μm, more desirably.
0.5 to 3 μm.

[0050] Next, a plating resist is formed on the electroless plating film. As a plating resist composition,
In particular, it is desirable to use a composition composed of an acrylate of a cresol novolak type epoxy resin or an acrylate of a phenol novolak type epoxy resin and an imidazole curing agent. Alternatively, a commercially available dry film may be used.

[0051] Next, the substrate on which the electroless plating film is formed is washed with water at 10 to 35 ° C, preferably 15 to 30 ° C. The reason is that when the washing temperature exceeds 35 ° C., water evaporates, the surface of the electroless plating film is dried and oxidized, and the electrolytic plating film does not deposit. For this reason, the electroless plating film is dissolved by the etching process, and a portion where no conductor exists is generated. On the other hand, if the temperature is lower than 10 ° C., the solubility of the contaminant in water decreases, and the cleaning power decreases. In particular, the diameter of the via hole land
When the thickness is 200 μm or less, the plating resist repels water, so that water is easily volatilized, and the problem of non-precipitation of electrolytic plating is likely to occur. In addition, various surfactants, acids, and alkalis may be added to the washing water. After the cleaning, the substrate may be washed with an acid such as sulfuric acid.

[0052] Next, the plating resist non-formed portion is subjected to electrolytic plating to provide a conductor circuit and a conductor portion serving as a via hole. Here, it is desirable to use copper plating as the electrolytic plating, and its thickness is 10 to 20 μm.
m is good.

[0053] Furthermore, after removing the plating resist, the electroless plating film under the plating resist is dissolved and removed with an etching solution comprising a mixed solution of sulfuric acid and hydrogen peroxide or an aqueous solution of sodium persulfate, ammonium persulfate, etc. An independent conductor circuit composed of two layers of electrolytic plating films and via holes are obtained.

(6) Multilayering of Wiring Board After forming a roughened layer on the surface of the conductor circuit formed in (5), the steps (4) and (5) are repeated to form a further upper layer conductor circuit. By providing, a predetermined multilayer printed wiring board is manufactured.

[0055]

Example (Example 1) A. Preparation of adhesive for electroless plating of upper layer. 35 parts by weight of a resin solution prepared by dissolving a 25% acrylated cresol novolak type epoxy resin (manufactured by Nippon Kayaku Co., Ltd., molecular weight 2500) in DMDG at a concentration of 80 wt%, 35 parts by weight, and 3.15 parts by weight of a photosensitive monomer (Toa Gosei Co., Aronix M315) Part, antifoaming agent (manufactured by San Nopco, S-65) 0.5 part by weight, NMP
3.6 parts by weight were mixed with stirring. . After mixing 12 parts by weight of polyethersulfone (PES), 7.2 parts by weight of an epoxy resin particle (manufactured by Sanyo Chemical Industries, 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, Further, 30 parts by weight of NMP was added and mixed by stirring with a bead mill. . 2 parts by weight of an imidazole curing agent (2E4MZ-CN, manufactured by Shikoku Chemicals), a photoinitiator (Irgacure I-, manufactured by Ciba-Geigy)
907) 2 parts by weight, photosensitizer (DETX-S, manufactured by Nippon Kayaku) 0.2
Parts by weight and 1.5 parts by weight of NMP were mixed with stirring. These were mixed to prepare an adhesive for electroless plating used as an upper adhesive layer constituting a two-layer interlayer resin insulating layer.

B. Preparation of lower interlayer resin insulation agent 35 parts by weight of a resin solution prepared by dissolving a 25% acrylate of cresol novolac type epoxy resin (manufactured by Nippon Kayaku Co., Ltd., molecular weight: 2500) at a concentration of 80 wt% in DMDG, and 4 parts by weight of a photosensitive monomer (Toa Gosei Co., Aronix M315) Parts, defoamer (manufactured by San Nopco, S-65) 0.5 parts by weight, NMP 3.6 parts
The parts by weight were mixed with stirring. . After mixing 12 parts by weight of polyether sulfone (PES) and 14.49 parts by weight of an epoxy resin particle (manufactured by Sanyo Kasei Co., Ltd., polymer pole) having an average particle diameter of 0.5 μm, 30 parts by weight of NMP was further added and stirred with a bead mill. Mixed. . 2 parts by weight of an imidazole curing agent (2E4MZ-CN, manufactured by Shikoku Chemicals), a photoinitiator (Irgacure I-, manufactured by Ciba-Geigy)
907) 2 parts by weight, photosensitizer (DETX-S, manufactured by Nippon Kayaku) 0.2
Parts by weight and 1.5 parts by weight of NMP were mixed with stirring. These were mixed to prepare a resin composition to be used as a lower insulating layer constituting a two-layer interlayer resin insulating layer.

C. Preparation of Resin Composition for Filling Through Holes Cresol novolak type epoxy resin (manufactured by Yuka Shell,
Epicoat 152) 3.5 parts by weight, bisphenol F type epoxy resin (manufactured by Yuka Shell, Epicoat 807) 14.1 parts by weight, ultrafine silica particles having an average particle diameter of 14 nm (Aerosil R20)
2) 1.0 part by weight, imidazole curing agent (Shikoku Chemicals, 2E
4MZ-CN) 1.2 parts by weight, 100 parts by weight of copper powder having an average particle diameter of 15 μm are kneaded with three rolls, and the viscosity of the mixture is 22 ± 1.
The temperature was adjusted to 200 to 300 Pa · s at ℃ to prepare a resin composition (resin filler) 5 for filling through holes.

D. Manufacturing method of printed wiring board (1) 18 μm on both sides of substrate 1 made of glass epoxy resin or BT (bismaleimide triazine) resin having a thickness of 1 mm
A copper-clad laminate on which m copper foils 2 were laminated was used as a starting material (see FIG. 3A). First, the copper-clad laminate was drilled (see FIG. 3B).

Next, a palladium-tin colloid is adhered, and electroless plating is performed with the following composition, and 2 μm is applied to the entire surface of the substrate.
m of electroless plating film was formed. [Electroless plating aqueous solution] EDTA 150 g / l Copper sulfate 20 g / l HCHO 30 ml / l NaOH 40 g / l α, α'-bipyridyl 80 mg / l PEG 0.1 g / l [Electroless plating conditions] 70 ° C. 30 minutes at liquid temperature

Further, electrolytic copper plating was performed under the following conditions to form an electrolytic copper plating film having a thickness of 15 μm (FIG. 3C).
reference). [Electroplating aqueous solution] Sulfuric acid 180 g / l Copper sulfate 80 g / l Additive (manufactured by Atotech Japan, trade name: Capparaside GL) 1 ml / l [Electroplating conditions] Current density 1 A / dm ² hours 30 minutes Temperature Room temperature

(2) The substrate on which the conductor (including the through hole 3) composed of the electroless copper plating film and the electrolytic copper plating film is formed on the entire surface is washed with water, dried, and then used as an oxidation bath using NaOH.
(20 g / l), NaClO ₂ (50 g / l), Na ₃ PO ₄ (15.0 g / l)
1) aqueous solution of NaOH (2.7 g /
1), subjected to an oxidation-reduction treatment using an aqueous solution of NaBH ₄ (1.0 g / l) to provide a roughened layer 4 on the entire surface of the conductor including the through hole 3 (see FIG. 3D).

(3) The resin filler 5 prepared in the above C was filled into the through hole 3 by screen printing, dried and cured. Then, the filler 5 protruding from the roughened layer 4 and the through hole 3 on the upper surface of the conductor is removed by belt sanding using # 600 belt abrasive paper (manufactured by Sankyo Rikagaku Co., Ltd.). The substrate surface was flattened by buffing to remove it (see FIG. 3 (e)).

(4) An electroless copper plating film having a thickness of 0.6 μm is formed by applying a palladium catalyst (manufactured by Atotech) to the substrate surface flattened in the above (3) and performing electroless copper plating according to a conventional method. 6 was formed (see FIG. 3 (f)).

(5) Next, electrolytic copper plating is performed under the following conditions to form an electrolytic copper plating film 7 having a thickness of 15 μm, thickening a portion to be a conductor circuit 9, and filling the through hole 3. A portion to be a conductor layer (lid plating layer) 10 covering the material 5 was formed. [Electroplating aqueous solution] Sulfuric acid 180 g / l Copper sulfate 80 g / l Additive (manufactured by Atotech Japan, trade name: Capparaside GL) 1 ml / l [Electroplating conditions] Current density 1 A / dm ² hours 30 minutes Temperature Room temperature

(6) A commercially available photosensitive dry film is stuck on both sides of the substrate on which the portions to be the conductor circuits 9 and the conductor layers 10 are formed, and a mask is placed on the substrate, and exposure is performed at 100 mJ / cm ² .
The resist was developed with 8% sodium carbonate to form an etching resist 8 having a thickness of 15 μm (see FIG. 4A).

(7) Then, the plating film in the portion where the etching resist 8 is not formed is dissolved and removed by etching using a mixed solution of sulfuric acid and hydrogen peroxide, and the etching resist 8 is further washed with a 5% KOH aqueous solution. By peeling and removing, a conductor layer (lid plating layer) 10 covering the independent conductor circuit 9 and the filler 5 was formed (see FIG. 4 (b)).

(8) Next, the entire surface including the side surface of the conductor layer (lid plating layer) 10 covering the conductor circuit 9 and the filler 5 is coated with Cu-
2.5-μm-thick roughened layer (rough layer) made of Ni-P alloy
Is formed on the surface of the roughened layer 11 and has a thickness of 0.3 μm.
An Sn layer was formed (see FIG. 4C, the Sn layer is not shown). The formation method is as follows. That is, the substrate was acid-degreased and soft-etched, then treated with a catalyst solution comprising palladium chloride and an organic acid to provide a Pd catalyst, and after activating the catalyst, copper sulfate 8 g / l,
It consists of an aqueous solution of nickel sulfate 0.6 g / l, citric acid 15 g / l, sodium hypophosphite 29 g / l, boric acid 31 g / l, and surfactant (Nissin Chemical Industries, Surfynol 465) 0.1 g / l. Plating was performed in an electroless plating bath of pH = 9, and a roughened layer 11 of a Cu—Ni—P alloy was provided on the surface of the conductor layer 10 covering the conductor circuit 9 and the filler 5. Then, using 0.1 mol / l of tin borofluoride and 1.0 mol / l of thiourea,
A Cu-Sn substitution reaction was performed at a temperature of 50 ° C. and a pH of 1.2 to provide a 0.3 μm thick Sn layer on the surface of the roughened layer 11 (the Sn layer is not shown).

(9) An interlayer resin insulating material of B (viscosity 15 Pa · s) is applied on both sides of the substrate by a roll coater, and
After standing for 20 minutes, drying was performed at 60 ° C. for 30 minutes to form an insulating agent layer. Further, an adhesive for electroless plating of A (viscosity: 8 Pa · s) is applied on the insulating layer using a roll coater, and dried at 55 ° C. for 40 minutes to form an adhesive layer.
An interlayer resin insulating layer 12 was formed (see FIG. 4 (d)). At this time, the surface of the interlayer resin insulating layer 12 was not flat due to unevenness between the conductors.

(10) A polyethylene terephthalate film (translucent film) 18 is adhered to the surface of the interlayer resin insulating layer 12 formed in the above (9), and then sandwiched by a stainless steel plate 20 to obtain 20 kgf / cm ² , And hot-pressed for 20 minutes while heating at 65 ° C. in a heating furnace (see FIG. 4 (e)). The surface of the interlayer resin insulating agent layer 12 was flattened by this heating press.

(11) On both surfaces of the substrate flattened in the above (10),
A photomask film on which a black circle of 85 μmφ was printed was brought into close contact with the photomask film, and exposed at 500 mJ / cm ² using an ultra-high pressure mercury lamp.
This was spray-developed with a DMDG solution to form an opening serving as a 85 μmφ via hole in the interlayer resin insulating layer 12. Further, the substrate was exposed to 3000 mJ / cm ² using an ultra-high pressure mercury lamp, and was exposed at 100 ° C. for 1 hour.
By performing a heat treatment at 50 ° C. for 5 hours, an interlayer resin insulating layer 12 having a thickness of 35 μm and having an opening (opening 13 for forming a via hole) having excellent dimensional accuracy corresponding to a photomask film was formed (FIG. 4). (f)). Note that the tin plating layer was partially exposed in the opening serving as the via hole.

(12) The substrate in which the opening for forming the via hole was formed was immersed in an 800 g / l chromic acid aqueous solution at 70 ° C. for 19 minutes, and the epoxy resin particles existing on the surface of the adhesive layer of the interlayer resin insulating layer 12 were removed. Was dissolved and removed to make the surface of the interlayer resin insulating layer 12 rough (3 μm in depth), and then immersed in a neutralizing solution (manufactured by Shipley) and then washed with water. Further, by applying a palladium catalyst (manufactured by Atotech) to the surface of the substrate subjected to the surface roughening treatment, a catalyst nucleus was attached to the surface of the interlayer resin insulating layer 12 and the inner wall surface of the via hole opening 13.

(13) The substrate was immersed in an aqueous electroless copper plating solution having the following composition to form an electroless copper plating film 14 having a thickness of 0.6 μm on the entire rough surface (see FIG. 5A). At this time, since the plating film was thin, irregularities were observed on the surface of the electroless plating film. [Electroless plating aqueous solution] EDTA 150 g / l Copper sulfate 20 g / l HCHO 30 ml / l NaOH 40 g / l α, α'-bipyridyl 80 mg / l PEG 0.1 g / l [Electroless plating conditions] 70 ° C. 30 minutes at liquid temperature

(14) Electroless plating film 14 formed in (13)
A commercially available photosensitive dry film was stuck thereon, a mask was placed, exposed at 100 mJ / cm ² , developed with 0.8% sodium carbonate, and a plating resist 16 having a thickness of 15 μm was provided (FIG. 5 (b) )).

(15) Then, the substrate is washed with water at 50 ° C., degreased, washed with water at 25 ° C., and further washed with sulfuric acid.
Electrolytic copper plating was performed under the following conditions to form an electrolytic copper plating film 15 having a thickness of 15 μm (see FIG. 5C). [Electroplating aqueous solution] Copper sulfate 180 g / l Copper sulfate 80 g / l Additive (Captec SideGL, manufactured by Adtec Japan) 1 ml / l [Electroplating conditions] Current density 1 A / dm ² hours 30 minutes Temperature Room temperature

(16) After the plating resist 16 is peeled and removed with a 5% KOH aqueous solution, the electroless plating film 14 under the plating resist 16 is dissolved and removed by etching with a mixed solution of sulfuric acid and hydrogen peroxide. Electrolytic copper plating film 14 and electrolytic copper plating film
A conductor circuit (including the via hole 17) 9 made of 15 and having a thickness of 18 μm was formed (see FIG. 5D). In addition, 80 at 70 ° C
The surface of the adhesive layer for electroless plating between the conductor circuits located in the portion where the conductor circuit is not formed is etched by 1 μm by immersing the substrate in a 0 g / l chromic acid aqueous solution for 3 minutes to remove the palladium catalyst remaining on the surface. did.

(17) The substrate on which the conductor circuit 9 was formed was coated with copper sulfate 8 g / l, nickel sulfate 0.6 g / l, and citric acid 15 g / l.
1, sodium hypophosphite 29 g / l, boric acid 31 g / l,
Surfactant (Nissin Chemical Industries, Surfynol 465)
It was immersed in an electroless plating solution having a pH of 9 consisting of 0.1 g / l, and a 3 μm-thick copper-nickel
A roughened layer 11 made of phosphorus was formed. At this time, when the formed roughened layer 11 was analyzed by EPMA (X-ray fluorescence spectrometer), Cu: 98 mol%, Ni: 1.5 mol%, P: 0.5 mol%
Was the composition ratio. In addition, tin borofluoride 0.1 mol /
1, using 1.0 mol / l aqueous solution of thiourea at a temperature of 50 ° C.
The Cu-Sn substitution reaction was performed under the condition of pH = 1.2,
A Sn layer having a thickness of 0.3 μm was provided on the surface of No. 11 (the Sn layer is not shown).

(18) By repeating the above steps (9) to (17), a conductor circuit of an upper layer was further formed to obtain a multilayer wiring board. However, Sn substitution was not performed (see FIG. 6 (a)).

(19) On the other hand, 46.67 parts by weight of a photosensitizing oligomer (molecular weight 4000) in which 60% by weight of a cresol novolak type epoxy resin (manufactured by Nippon Kayaku) dissolved in DMDG was acrylated with 50% of epoxy groups, 15.0 parts by weight of bisphenol A type epoxy resin (Eicoat 1001, manufactured by Yuka Shell) dissolved in methyl ethyl ketone, 15.0 parts by weight, imidazole curing agent (2E4MZ-CN, Shikoku Chemicals) 1.6 parts by weight, photosensitive monomer polyvalent acrylic 3 parts by weight of a monomer (R604, manufactured by Nippon Kayaku), 1.5 parts by weight of a polyvalent acrylic monomer (DPE6A, manufactured by Kyoeisha Chemical Co., Ltd.) and 0.71 part by weight of a defoaming agent (S-65, manufactured by San Nopco) were mixed. Further, 2 parts by weight of benzophenone (Kanto Chemical) as a photoinitiator and 0.2 parts by weight of Michler's ketone (Kanto Chemical) as a photosensitizer were added to this mixture, and To obtain a strike composition.

(20) The solder resist composition was applied to both sides of the multilayer wiring board obtained in the above (18) in a thickness of 20 μm. Next, after performing a drying process at 70 ° C. for 20 minutes and at 70 ° C. for 30 minutes, a circular pattern (mask pattern) of the solder resist opening portion drawn by the chromium layer is 5 mm thick.
The soda lime glass substrate was exposed to ultraviolet light of 1000 mJ / cm ² with the chromium layer formed side in close contact with the solder resist layer, and subjected to DMTG development treatment. Further, heat treatment was performed 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 open the upper surface, via holes and lands of the solder pads (opening diameter: 200 μm). A solder resist pattern layer 19 (thickness: 20 μm) was formed.

(21) Next, the solder resist pattern layer 18
The substrate on which was formed was immersed in an electroless nickel plating solution having a pH of 5 consisting of an aqueous solution of nickel chloride 30 g / l, sodium hypophosphite 10 g / l, and sodium citrate 10 g / l for 20 minutes. Nickel plating layer 21 of 5 μm thickness
Was formed. Further, the substrate was placed in an electroless gold plating solution comprising an aqueous solution of potassium cyanide 2 g / l, ammonium chloride 75 g / l, sodium citrate 50 g / l, and sodium hypophosphite 10 g / l at 93 ° C. Immerse for 23 seconds and apply a 0.03μm thick gold plating layer on the nickel plating layer 21
22 formed.

(22) Solder resist pattern layer
Solder paste was printed in the opening 19 and reflowed at 200 ° C. to form a solder bump (solder body) 23, and a multilayer printed wiring board having the solder bump 23 was manufactured (see FIG. 6 (b)). .

Comparative Example 1 (1) (1) to (8) of Example 1 were performed. (2) Preparation of resin filler. 100 parts by weight of bisphenol F type epoxy monomer (manufactured by Yuka Shell, molecular weight 310, YL983U), Si coated with a silane coupling agent on the surface and having an average particle size of 1.6 μm
O ₂ spherical particles (manufactured by Admatech, CRS 1101-CE, where the maximum particle size is not more than the thickness (15 μm) of the inner layer copper pattern described later) 170 parts by weight, leveling agent (manufactured by San Nopco, Perenol S4) 1.5 The weight of the mixture is kneaded with three rolls and the viscosity of the mixture is 45,000 ~ at 23 ± 1 ° C.
Adjusted to 49,000cps. . Imidazole curing agent (2E4MZ-CN, manufactured by Shikoku Chemicals) 6.5
Parts by weight. These were mixed to prepare a resin filler. (3) This resin filler is filled between the conductor circuits by applying to both surfaces of the substrate using a roll coater, and then,
1 hour at 100 ° C, 3 hours at 120 ° C, 1 hour at 150 ° C, 1
The composition was cured by performing a heat treatment at 80 ° C. for 7 hours. (4) One surface of the substrate after the treatment of (3) is filled with resin on the surface of the inner layer copper pattern and the land surface of the through hole by belt sander polishing using # 600 belt polishing paper (manufactured by Sankyo Rikagaku). Polish so that no material remains, 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. However, the lid plating peeled off during this polishing. In this regard, according to the method of the first embodiment according to the present invention, it is possible to realize a high density of wirings and through holes without causing a defect in the lid plating layer.

Comparative Example 2 (1) 18 μm on both sides of a 1 mm thick glass epoxy resin or BT (bismaleimide triazine) resin substrate
A copper-clad laminate on which m copper foils were laminated was used as a starting material. First, this copper clad laminate is drilled, a plating resist is formed, and then an electroless plating process is performed to form a through-hole. Further, the copper foil is etched in a pattern according to a conventional method to form a substrate. Inner layer copper patterns were formed on both sides. (2) The substrate on which the inner layer copper pattern was formed was washed with water and dried, and then NaOH (10 g / l), NaClO ₂ (40 g / l), Na ₃ P
An aqueous solution of O ₄ (6 g / l) was oxidized with NaOH (10 g / l).
1) An aqueous solution of NaBH ₄ (6 g / l) was used as a reducing bath, and a roughened layer was provided on the entire surface of the conductor circuit and the through hole. (3) Preparation of resin filler. 100 parts by weight of bisphenol F type epoxy monomer (manufactured by Yuka Shell, molecular weight 310, YL983U), Si coated with a silane coupling agent on the surface and having an average particle size of 1.6 μm
O ₂ spherical particles (manufactured by Admatech, CRS 1101-CE, where the maximum particle size is not more than the thickness (15 μm) of the inner layer copper pattern described later) 170 parts by weight, leveling agent (manufactured by San Nopco, Perenol S4) 1.5 The weight of the mixture is kneaded with three rolls and the viscosity of the mixture is 45,000 ~ at 23 ± 1 ° C.
Adjusted to 49,000cps. . Imidazole curing agent (2E4MZ-CN, manufactured by Shikoku Chemicals) 6.5
Parts by weight. These were mixed to prepare a resin filler. (4) This resin filler is applied to both sides of the substrate using a roll coater to fill the space between the conductor circuits or into the through holes, and then at 100 ° C for 1 hour, at 120 ° C for 3 hours, at 150 ° C. Heat treatment was performed for 1 hour at 180 ° C. for 7 hours to cure. That is, in this step, the resin filler is filled between the inner layer copper patterns or in the through holes. (5) One surface of the substrate after the treatment in (4) is filled with resin on the surface of the inner layer copper pattern and the land surface of the through hole by belt sanding using # 600 belt polishing paper (manufactured by Sankyo Rikagaku). Polish so that no material remains, 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. In this way, the surface layer of the resin filler filled in the through-holes and the roughened layer on the upper surface of the inner conductor circuit are removed to smooth both surfaces of the substrate, and the resin filler and the side surface of the conductor circuit are roughened. To obtain a wiring board in which the inner wall surfaces of the through holes and the resin filler are firmly adhered to each other through the roughened layer. That is, by this step, the surface of the resin filler and the surface of the inner layer copper pattern are flush with each other. Here, the Tg point of the filled cured resin is
The thermal expansion coefficient was 154.5 ° C. and the linear thermal expansion coefficient was 44.5 × 10 ⁻⁵ / ° C. (6) Further, a Cu—Ni—P alloy coating layer having a thickness of 5 μm is formed on the exposed conductor circuit and the land upper surface of the through hole, and a thickness of 2 μm.
A Cu-Ni-P needle-like alloy roughened layer having a thickness of μm and a Sn metal coating layer having a thickness of 0.3 μm were provided on the surface of the roughened layer. The method for forming these layers is as follows. That is, the substrate was acid-degreased and soft-etched, and then treated with a catalyst solution comprising palladium chloride and an organic acid to provide a Pd catalyst. After activating this catalyst, copper sulfate 8 g / l, nickel sulfate 0.6g
/ L, citric acid 15g / l, sodium hypophosphite 29g /
pH of an aqueous solution containing 0.1 g / l of boric acid, 31 g / l of boric acid and 0.1 g / l of a surfactant (Surfynol 104, manufactured by Nissin Chemical Co., Ltd.)
The substrate was immersed in the electroless copper plating bath of No. 9 and the substrate was vibrated in the vertical direction at a rate of once every four seconds. After plating was deposited, air was bubbled three minutes after the plating deposition to form a copper conductor circuit and a through hole. A coating layer of a non-needle alloy of Cu-Ni-P was first deposited on the surface, and then a needle-like alloy of Cu-Ni-P was deposited to provide a roughened layer. 30 minutes at 100 ° C, 120 ° C
And heat treatment at 150 ° C. for 2 hours with a 10% by volume aqueous solution of sulfuric acid and a 0.2 mol / l aqueous solution of borofluoric acid, and then 0.1 mol / l of tin borofluoride and 1.0 mol of thiourea.
Using a mol / l aqueous solution, a Cu-Sn substitution reaction was performed at a temperature of 50 ° C and a pH of 1.2, and a 0.3 µm thick
A Sn metal coating layer was provided. (7) Then, (9) to (22) of Example 1 were performed to manufacture a multilayer printed wiring board having solder bumps.

The multilayer printed wiring board thus manufactured was subjected to a heat cycle test at −55 ° C. to 125 ° C. for 1000 times, and the presence or absence of cracks in the interlayer resin insulating layer was confirmed by an optical microscope. Table 1 shows the results. Also,
The mountability of electronic components was evaluated.

As is clear from the results shown in Table 1, the printed wiring board of the present invention has excellent crack resistance under heat cycle conditions. There was no problem with the mountability of electronic components.

[0086]

[Table 1]

[0087]

As described above, according to the present invention, it is possible to manufacture a multilayer printed wiring board having a high density of wirings and through holes without causing a defect in the lid plating layer. Moreover, the multilayer printed wiring board of the present invention
Excellent crack resistance under conditions such as heat cycle.

[Brief description of the drawings]

FIG. 1 is a schematic view showing a process of manufacturing a multilayer printed wiring board according to a conventional technique.

FIG. 2 is a diagram showing surface irregularities of an interlayer resin insulating layer caused by an inner conductor circuit.

FIGS. 3A to 3F are views showing a part of a manufacturing process of a multilayer printed wiring board according to the present invention.

FIGS. 4A to 4F are views showing a part of a manufacturing process of a multilayer printed wiring board according to the present invention.

5 (a) to 5 (d) are views showing a part of the manufacturing process of the multilayer printed wiring board according to the present invention.

FIGS. 6A and 6B are diagrams showing a part of a manufacturing process of a multilayer printed wiring board according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Substrate 2 Copper foil 3 Through hole 4,11 Roughened layer 5 Filler 6,14 Electroless plating film 7,15 Electrolytic plating film 8 Etching resist 9 Conductor circuit 10 Conductor layer 12 Interlayer resin insulation layer (of interlayer resin insulation agent) Layer) 13 Via hole opening 16 Plating resist 17 Via hole 18 Transparent film 19 Solder resist layer 20 Metal plate (stainless steel plate) 21 Nickel plating layer 22 Gold plating layer 23 Solder bump

 ──────────────────────────────────────────────────続 き Continuing on the front page F term (reference) 5E346 AA12 AA32 AA43 AA54 CC02 CC04 CC09 CC10 CC14 CC32 CC33 CC34 CC38 CC39 CC52 CC55 CC57 DD02 DD12 DD16 DD17 DD23 DD32 DD33 EE03 EE04 EE06 EE09 EE13 EE19 EE33 EE38 GG17 GG17 GG17 GG17 FF17GG HH18 HH25 HH26

Claims (8)

[Claims] 1. A multilayer printed circuit having a structure in which a conductive circuit is formed on a substrate via an interlayer resin insulating layer, a through hole is provided in the substrate, and the through hole is filled with a filler. In the wiring board, immediately above the through-hole, a conductor layer is formed to cover the exposed surface of the filler from the through-hole, and the conductor layer and the conductor circuit located on the same layer have the entire surface including the side surface. A multilayer printed wiring board, characterized in that a roughened layer is formed on a surface of the roughened layer, and a concave portion between conductors is filled in a surface of the roughened layer, and an interlayer resin insulating layer having a flat surface is formed. 2. At least the following steps: Forming a through hole in the substrate; Providing a roughened layer on the inner wall of the through hole; Filling the through hole with a filler; Forming a conductor layer directly above the through hole so as to cover a surface of the filler exposed from the through hole; Providing a roughened layer on the entire surface including the side of the conductor layer and the conductor circuit located on the same layer; Providing a layer of an uncured interlayer resin insulating material, heat-pressing the layer of the interlayer resin insulating material to flatten its surface, and then performing a curing process to form an interlayer resin insulating layer; Forming a conductor circuit on the interlayer resin insulation layer,
A method for manufacturing a multilayer printed wiring board, comprising: 3. The method according to claim 2, wherein the roughened layer in the step is a redox treatment layer. 4. In the step of forming a photosensitive interlayer resin insulating layer, a light-transmitting film is attached to a surface of the interlayer resin insulating agent before hot pressing, and an interlayer is formed via the light-transmitting film. 3. The method according to claim 2, wherein the surface of the layer of the resin insulating material is flattened by a hot press, then hardened by exposure, and thereafter, the translucent film is removed and developed. 5. The method according to claim 2, wherein the heating press in the step is performed by pressing a metal plate or a metal roll while heating the layer of the interlayer resin insulating material. 6. The method according to claim 6, wherein the step of heating the layer of the interlayer resin insulating material containing an epoxy resin as a main component is performed at a temperature of 40 ° C.
3. The method according to claim 2, wherein the heating is performed under the conditions of −60 ° C., a pressure of 3.5 to 6.5 kgf / cm ² and a pressing time of 30 to 90 seconds. 7. The manufacturing method according to claim 2, wherein an opening is provided in a portion of the interlayer resin insulating layer immediately above the through hole to form a conductor circuit and a via hole. 8. The method according to claim 2, wherein the filler is made of metal particles, a thermosetting or thermoplastic resin, and a curing agent.